Description:TECHNICAL FIELD
[0001] The present disclosure relates generally to the field of robotic surgical systems and, more particularly, to a robotic surgical system for fulcrum-constrained control of surgical instruments.
BACKGROUND
[0002] Minimally invasive surgical (MIS) techniques (for example, laparoscopy) have revolutionized modern surgery by reducing patient trauma, lowering recovery times, and minimizing scarring. The MIS techniques involve the insertion of long, slender instruments through small incisions in the body of the patient. However, due to the restricted nature of such access points, the surgical instrument must pivot about the entry site, creating a fulcrum effect. The constraint in movement inverts the natural relationship between hand motion and tool motion, which complicates precise control.
[0003] Traditional robotic systems employed in l existing surgical robots address the fulcrum constraint using mechanical remote center of motion (RCM) mechanisms. The traditional robotic systems rely on rigid linkages and calibrated hardware configurations that mechanically enforce the fixed pivot point at the incision. Additionally, existing traditional robotic systems employ conventional inverse kinematics algorithms using Denavit-Hartenberg (DH) parameters or numerical solvers to approximate the desired tip position while respecting the fulcrum constraint. Despite their effectiveness, the existing solutions have limitations, including hardware complexity, calibration sensitivity, and limited adaptability to varying surgical scenarios.
[0004] Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks.

SUMMARY
[0005] The present disclosure provides a robotic surgical system. The present disclosure provides a solution to the technical problem of how to control the motion of a surgical instrument that passes through a fixed fulcrum point (for example, an incision site) while maintaining the spatial constraint that the elongated shaft of the surgical instrument must always pivot about the pivot point without causing lateral translation or displacement. The technical problem arises particularly in minimally invasive surgical procedures, where any unintended force or movement at the fulcrum may lead to tissue damage or misalignment of a tip of the surgical instrument. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in the prior art by offering an inverse kinematics (IK) approach that accurately calculates the necessary joint angles, including pitch and articulation angles, to position and orient the tip of the surgical instrument, while strictly maintaining the fulcrum point as a fixed pivot in space.
[0006] One or more objectives of the present disclosure is achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.
[0007] In one aspect, the present disclosure provides a robotic surgical system, comprising:
a patient- side cart comprising one or more robotic arms, wherein at least one robotic arm comprises a surgical instrument comprising:
an elongated shaft defining a longitudinal axis;
an end effector disposed at a distal end of the elongated shaft; and
a plurality of actuators configured to manipulate the surgical instrument;
a surgeon master console configured to control movement of the surgical instrument and operably connected to a controller, wherein the controller is configured to:
establish a reference coordinate frame with origin at a jaw rotation axis of the surgical instrument;
determine a jaw angle and a pitch angle of the end effector based on a selected position and a selected orientation of the end effector received from the surgeon master console;
determine a position and an orientation of an end of the at least one robotic arm about the fulcrum point based on the spatial relationship between a fulcrum point, a pitch joint, and a position of the end effector; and
generate control signals to the plurality of actuators and the at least one robotic arm such that the end effector achieves the selected position and the selected orientation while the elongated shaft always passes through the fulcrum point without lateral translation, wherein the fulcrum point is maintained as a fixed spatial constraint which ensure the elongated shaft consistently intersects the fulcrum point and prevents unintended forces at the surgical location.
[0008] Establishing a reference coordinate frame at the jaw rotation axis and using an established reference coordinate frame to determine the jaw angle and pitch angle based on the selected position and orientation of the end effector enables the robotic surgical system to accurately model the spatial relationship between the fulcrum point, the pitch joint, and the end effector. The integrated computational framework ensures that the elongated shaft of the surgical instrument consistently intersects the fulcrum point during motion, preserving the pivot constraint across all degrees of freedom. The combined implementation of real-time inverse kinematics calculations and coordinated control signal generation allows the robotic arm and the plurality of actuators to respond dynamically to surgeon input, maintaining precise alignment through the fulcrum point during both linear advancement and angular articulation of the instrument. As a result, the surgical instrument can execute complex trajectories with high fidelity while avoiding lateral displacement at the incision site, thereby minimizing the risk of tissue trauma and maintaining the anatomical safety of the procedure. The elimination of mechanical linkages to enforce fulcrum-based motion not only simplifies the structural design of the robotic surgical system but also reduces the possibility of mechanical misalignment or calibration drift over time. Simultaneously, the responsiveness and computational efficiency of the control system provide surgeons with smooth and intuitive handling of the instrument tip, even during intricate surgical manoeuvres. The combination of geometry-based control logic, fulcrum-constrained actuation, and real-time feedback enables stable, accurate, and minimally invasive operation, enhancing both the safety and effectiveness of robotic-assisted surgical interventions.
[0009] In an implementation, determining the jaw angle comprises determining a normal vector to a plane containing vectors from the fulcrum point to the pitch joint and from the pitch joint to the end effector, calculating an angle between the longitudinal axis of the end effector and the normal vector with reference to an established coordinate frame at the jaw rotation axis and deriving the jaw angle as the complementary angle to the angle between the longitudinal axis of the end effector and the normal vector. In such an implementation, determining the jaw angle through geometric calculation ensures precise and consistent articulation of the end effector relative to the fixed fulcrum point. The approach of determining the jaw angle enhances accuracy during surgical manipulation, reduces sensitivity to mechanical tolerances, and enables real-time computation without reliance on iterative numerical methods.
[0010] In an implementation, determining the pitch angle comprises projecting the longitudinal axis of the end effector onto a plane containing the fulcrum point and the elongated shaft with reference to the established coordinate frame at the jaw rotation axis, normalizing the projected vector to obtain a direction vector along the pitch axis; determining vectors representing segments of the surgical instrument based on physical dimensions of the segments of the surgical instrument and determining the pitch angle using the arctangent of the ratio between the magnitude of a first vector operation and a second vector operation of determined vectors. In such an implementation, determining the pitch angle by projecting the end effector’s longitudinal axis onto the plane defined by the fulcrum point and elongated shaft isolates true pitch motion. Further, normalizing the obtained projection and using real segment dimensions ensures geometric accuracy and calculating the pitch angle via arctangent of vector operations yields a signed, stable pitch angle, enabling precise control while preserving the fulcrum constraint and ensuring real-time responsiveness.
[0011] In another implementation, the controller is further configured to determine a position and an orientation of the end of the at least one robotic arm according to a predefined equation. In such an implementation, determining the position and orientation of the end of the at least one robotic arm using a predefined equation ensures deterministic and repeatable motion planning, which enhances the precision of instrument placement. An approach of using the predefined equation eliminates reliance on iterative solvers, reducing computational overhead and latency. The approach enables the robotic surgical system to maintain consistent alignment through the fulcrum point while accurately reaching the target pose, improving both surgical accuracy and system responsiveness.
[0012] In an implementation, the predefined equation defines a relationship between the position of the at least one robotic arm, the position of the fulcrum point, an effective length from the fulcrum point to the end effector, and a unit vector along the direction of the elongated shaft. In such an implementation, the relationship between the robotic arm position, the fulcrum point, the effective length to the end effector, and the unit vector along the shaft direction enables precise and efficient calculation of the position of the at least one robotic arm. The direct mathematical relationship ensures that the elongated shaft consistently intersects the fulcrum point, reducing positional error and avoiding unintended force at the insertion site. Further, the reduction in position error enhances control accuracy, simplifies computation, and supports real-time adjustments during dynamic surgical movements.
[0013] In yet another implementation, the effective length is the difference between a length of the elongated shaft and a length of the surgical instrument extending beyond the fulcrum point. In such an implementation, defining the effective length as the difference between the total length of the elongated shaft and the portion extending beyond the fulcrum point allows accurate modelling of the segment of the instrument operating inside the patient. The approach improves precision in calculating the position of the end effector and orientation, ensuring that control signals reflect the true working length. As a result, the robotic surgical system maintains precise alignment through the fulcrum point and enables safe, controlled manipulation within confined surgical spaces.
[0014] In yet another implementation, the controller determines an orientation of the surgical instrument by defining a first axis aligned with a direction vector of the elongated shaft, defining a second axis aligned with a unit vector perpendicular to the plane containing the fulcrum point and the elongated shaft and defining a third axis as a cross product of the first axis and the second axis to maintain an orthogonal coordinate system. In such an implementation, determining the orientation of the surgical instrument using three orthogonal axes derived from the shaft direction and the fulcrum constraint ensures a consistent and anatomically accurate local coordinate frame. The approach provides robust spatial orientation tracking, allowing precise control of the movements of the end effector. By maintaining the orthogonal frame through vector cross-products, the system avoids rotational drift and enhances stability and predictability during complex surgical manoeuvres.
[0015] In yet another implementation, the robotic surgical system further comprises a sensing module configured to track the position and orientation of the elongated shaft and provide feedback to the controller for maintaining the fulcrum point as the fixed spatial constraint. In such an implementation, the sensing module enables real-time tracking position and orientation of the elongated shaft, providing continuous feedback to the controller to maintain the fulcrum point as a fixed spatial constraint. Maintaining the fulcrum point as a fixed spatial constraint ensures precise fulcrum-constrained motion, prevents unintended forces at the incision site, and enhances surgical safety and instrument control, particularly in minimally invasive procedures.
[0016] In yet another implementation, the controller is further configured to continuously monitor the position of the fulcrum point relative to the established coordinate frame at the jaw rotation axis. In such an implementation, continuous monitoring of the fulcrum point relative to the coordinate frame at the jaw rotation axis allows the controller to detect any deviation or drift in real time, enabling immediate corrective action. The immediate corrective action enhances the accuracy and stability of motion of the surgical instrument, ensures adherence to the fixed pivot constraint, and reduces the risk of tissue trauma during surgical manipulation.
[0017] In yet another implementation, based on monitoring, the controller is further configured to detect any displacement of the fulcrum point and adjust the jaw angle and the pitch angle in real time to maintain the fulcrum as the fixed spatial constraint during surgical manipulation. In such an implementation, real-time detection and correction of fulcrum point displacement allows the robotic surgical system to dynamically adjust the jaw angle and the pitch angle, ensuring the surgical instrument continuously pivots about the intended fulcrum. The continuous pivot maintains surgical precision, prevents unintentional motion at the entry site, and enhances safety by minimizing the risk of tissue damage during dynamic procedures.
[0018] In another aspect, the present disclosure provides a method for controlling a surgical instrument in a robotic surgical system, the method comprising:
receiving, at a controller, a selected position and a selected orientation of an end effector of a surgical instrument from a surgeon master console;
establishing a coordinate frame with origin at a jaw rotation axis of the surgical instrument;
determining a jaw angle and a pitch angle of the end effector based on the selected position and the selected orientation of the end effector;
determining a position and an orientation of an end of at least one robotic arm about a fulcrum point based on a spatial relationship between the fulcrum point, a pitch joint, and a position of the end effector;
determining, in real time, commands of joint space configurations using forward and inverse kinematic models that keep an elongated shaft of the surgical instrument intersecting the fulcrum point while the end effector moves toward the selected position and orientation; and
generating control signals to a plurality of actuators and the robotic arm to ensure the end effector achieves the selected position and the selected orientation while the elongated shaft passes through the fulcrum point without lateral translation.
[0019] The method achieves all the advantages and technical effects of the robotic surgical system of the present disclosure.
[0020] It is to be appreciated that all the aforementioned implementation forms can be combined.
[0021] It has to be noted that all devices, elements, circuitry, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
[0022] Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
[0024] Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
FIG. 1 is a diagram illustrating a robotic surgical system, in accordance with an embodiment of the present disclosure;
FIG. 2 is a diagram illustrating a surgical instrument of the robotic surgical system, in accordance with an embodiment of the present disclosure;
FIG. 3 is a diagram illustrating a block diagram of the robotic surgical system, in accordance with an embodiment of the present disclosure;
FIG. 4 is a diagram illustrating the surgical instrument with assigned coordinate axes for performing kinematic calculation, in accordance with an embodiment of the present disclosure; and
FIG. 5 is a flowchart illustrating a method for operating the robotic surgical system, in accordance with an embodiment of the present disclosure.
[0025] In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION OF EMBODIMENTS
[0026] The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
[0027] FIG. 1 is a diagram illustrating a robotic surgical system, in accordance with an embodiment of the present disclosure. With reference to FIG. 1, there is shown a robotic surgical system 100, including a patient-side cart 110, a vision cart 120, and a surgeon master console 130.
[0028] The patient-side cart 110 is a mobile unit having a base mounted on wheels. The base includes locking mechanisms for securing the patient-side cart 110 in position. The patient-side cart 110 includes a vertical column extending upward from the base. The vertical column comprises a linear actuator enabling height adjustment. The patient-side cart 110 includes multiple robotic arms that extend from the vertical column. In some implementations, the multiple robotic arms include four robotic arms in which three robotic arms 112 are configured for surgical instrument manipulation and one robotic arm 113 is configured for endoscopic imaging. The robotic arms 112 include primary segments, secondary segments, and tertiary segments connected by rotational joints. The rotational joints contain servo motors enabling precise angular positioning. The robotic arms 112 include surgical instrument holders 114 at distal ends. The surgical instrument holders 114 comprise mechanical interfaces and electrical connectors. The mechanical interfaces, include spring-loaded clamps for instrument attachment. The electrical connectors transmit power and signals to mounted instruments. The patient-side cart 110 further includes at least one surgical instrument 140 mounted to the surgical instrument holders 114 at one of the robotic arms 112. The surgical instrument 140 includes elongated shafts with end effectors at distal tips. The end effectors include articulation mechanisms enabling pitch and yaw movements. The surgical instrument 140 includes internal drive cables connecting to motor units in the instrument holders. The drive cables actuate the end effector movements. The robotic arm 113 supports an endoscopic imaging system. Each of the robotic arms 112 includes additional degrees of freedom for camera positioning. The endoscopic imaging system includes dual high-definition camera sensors mounted at a distal end of the robotic arm 113. The dual camera sensors enable stereoscopic image capture. The endoscopic imaging system includes fibre optic light transmission bundles surrounding the camera sensors for illuminating the surgical field. The endoscopic imaging system enables both white light imaging and near-infrared fluorescence visualization. The endoscopic imaging system comprises glass rod lenses for controlling chromatic aberration and enhancing image quality.
[0029] The vision cart 120 is a mobile unit comprising a base with wheels and a vertical housing. The base contains power supply units and cooling systems. The vertical housing contains processing units and displays. The vertical housing includes ventilation channels for thermal management. The vision cart 120 includes a display 122 mounted at an upper portion of the vertical housing, wherein the display 122 comprises a high-definition LCD monitor with anti-glare coating. In some other embodiments, the vision cart 120 may include multiple displays. The vision cart 120 includes an electrosurgical unit (ESU) 124 mounted within the vertical housing. The vision cart 120 further includes endoscope light sources. The endoscope light sources comprise one or two light source units mounted within the vertical housing. The vision cart 120 includes an insufflator unit mounted within the vertical housing for creating and maintaining pneumoperitoneum. The vision cart 120 includes an uninterruptible power supply (UPS) system mounted within the base for providing backup power. The vision cart 120 further includes a video processing unit and a central processing unit within the vertical housing. The video processing unit includes dedicated graphics processors. The central processing unit comprises multiple processing cores. The vision cart 120 further includes data storage devices mounted within the vertical housing. In some implementations, the vision cart 120 comprises image enhancement processors for contrast adjustment and noise reduction. In some implementations, the vision cart 120 includes fluorescence imaging processors for tissue identification. In some implementations, the vision cart 120 includes augmented reality processors for data overlay generation.
[0030] The surgeon master console 130 includes a base structure supporting an operator seat and control interfaces. The base structure includes levelling mechanisms for stable positioning. The operator seat comprises height adjustment mechanisms and lumbar support systems. A display housing extends upward and forward from the base structure. The display housing contains a stereoscopic display system 134. The stereoscopic display system 134 includes dual display panels and optical elements. The optical elements include focusing mechanisms and eye tracking sensors. The surgeon master console 130 further includes master control manipulators 132 mounted on sides of the base structure in front of the operator seat. The master control manipulators 132 terminate in ergonomic hand grips. The hand grips contain pressure sensors and multi-function triggers. In some other embodiments, the hand grip may provide haptic feedback. In some implementations, the surgeon master console 130 further includes foot pedals mounted on a lower portion of the base structure. The foot pedals 136 include position sensors and tactile feedback mechanisms. A user interface comprising touchscreens mounts on the base structure between the master control manipulators 132. The touchscreens display system status information and configuration controls.
[0031] The patient-side cart 110, the vision cart 120, and the surgeon master console 130 connect through a communication network. The communication network comprises ethernet cables. In some other embodiments, the communication may be through any wireless communication protocol. The communication network includes redundant data pathways. The communication network transmits control signals from the master control manipulators 132 to the robotic arms 112. The control signals include position commands and gripper actuation commands. In some implementations, the communication network transmits imaging data from the endoscopic imaging system to the stereoscopic display system 134. The imaging data includes calibration parameters and camera position data. The robotic surgical system 100 includes monitoring systems connected to the communication network. The monitoring systems comprise voltage sensors, current sensors, temperature sensors, and position sensors.
[0032] In some implementations, the robotic surgical system 100 includes emergency stop mechanisms mounted on each component. The emergency stops mechanisms include physical switches and software-triggered stops. The robotic surgical system 100 includes power backup systems within each component. The power backup systems include batteries and uninterruptible power supplies. The robotic surgical system 100 includes fault detection processors within the vision cart 120. The fault detection processors monitor system parameters and component status.
[0033] In some implementations, the robotic surgical system 100 executes autonomous and semi-autonomous functions. In some implementations, the robotic surgical system 100 enables system upgrades through modular component replacement. The modular component replacement includes instrument interface upgrades and processing unit upgrades.
[0034] The robotic surgical system 100 enables minimally invasive surgical procedures. Exemplary surgical procedures may include, but not limited to, general surgery procedures, gynaecological procedures, urological procedures, cardiothoracic procedures, and otolaryngological procedures.
[0035] FIG. 2 is a diagram illustrating an exemplary surgical instrument of the robotic surgical system, in accordance with an embodiment of the present disclosure. FIG. 2 is described in conjunction with the elements of FIG. 1. With reference to FIG. 2, there is shown the surgical instrument 140 for use with the robotic surgical system 100 described in FIG. 1. The surgical instrument 140 comprises a proximal housing 200 and an end effector 210 connected by an elongated shaft 220. The proximal housing 200 includes a generally rectangular configuration with rounded edges for ergonomic handling. In some other implementations the proximal housing may have circular configuration. In yet another implementation, the proximal housing may have polygonal configuration. The proximal housing 200 comprises a top surface 230 having access apertures. The proximal housing 200 further includes side panels 232 with mounting fixtures positioned for secure attachment to the actuator on the robotic arms. The proximal housing 200 contains internal drive mechanisms for actuating the end effector 210. In some implementations, the proximal housing 200 includes electronic components for receiving control signals from the robotic surgical system 100.
[0036] The proximal housing 200 comprises a circular coupling interface 234 located on a front face. The circular coupling interface 234 includes mechanical registration features ensuring precise alignment during instrument mounting. The circular coupling interface 234 contains electrical contact arrays enabling signal transmission between the surgical instrument 140 and the robotic arm 112. The circular coupling interface 234 is further configured to enable wireless signal transmission between the surgical instrument 140 and the robotic arm 112. The wireless signal transmission may be facilitated using one or more wireless communication technologies, including but not limited to radio-frequency identification (RFID), Bluetooth, infrared (IR), near-field communication (NFC), or any other suitable wireless protocol.
[0037] The elongated shaft 220 extends from the circular coupling interface 234 of the proximal housing 200. The elongated shaft 220 comprises a rigid cylindrical structure having a substantially uniform diameter. The elongated shaft 220 includes an outer sheath fabricated from biocompatible materials. The elongated shaft 220 contains internal drive cables, and mechanical linkages for transmitting forces and signals from the proximal housing 200 to the end effector 210. In some implementations, the elongated shaft 220 includes articulation segments comprising flexible joints or linkages, enabling multi-degree-of-freedom angular positioning and enhanced dexterity of the end effector 210. In some implementations, the elongated shaft 220 may be modular or detachable, allowing for easy replacement or sterilization. Additionally, in configurations utilizing wireless communication (e.g., RFID or other wireless protocols), internal wiring may be minimized or optimized for power delivery only, with control signals transmitted wirelessly from the proximal housing 200 to onboard controllers associated with the end effector 210.
[0038] The end effector 210 mounts to a distal end of the elongated shaft 220. The end effector 210 comprises a wrist mechanism 250, providing additional degrees of freedom. The wrist mechanism 250 includes articulation joints enabling pitch and yaw movements of grasping jaws 252. In some implementations, the wrist mechanism 250 contains gearing assemblies for converting linear actuation into rotational movement. The grasping jaws 252 include opposed members with tissue-interfacing surfaces. The tissue-interfacing surfaces comprise grip-enhancing textures for secure tissue manipulation. In some implementations, the grasping jaws 252 include integrated sensors for force feedback. In some implementations, the grasping jaws 252 incorporate electrosurgical elements for tissue coagulation.
[0039] The surgical instrument 140 includes mechanical registration features ensuring proper orientation when mounted to the robotic arm 112. The surgical instrument 140 comprises sealing elements preventing fluid ingress during surgical procedures. The surgical instrument 140 includes sterilization-compatible materials enabling repeated reprocessing cycles.
[0040] In some implementations, the surgical instrument 140 comprises specialized end effectors for specific surgical tasks, including tissue cutting, needle driving, clip application, and suturing. In some implementations, the surgical instrument 140 includes integrated cameras for additional visualization capabilities. The surgical instrument 140 operates under the control of the surgeon master console 130 via the robotic arm 112 to enable precise tissue manipulation during minimally invasive surgical procedures.
[0041] FIG. 3 is a block diagram of the robotic surgical system, in accordance with an embodiment of the present disclosure. FIG. 3 is described in conjunction with the elements of FIGs. 1 to 2. With reference to FIG. 3, there is shown a block diagram of the robotic surgical system 100. The robotic surgical system 100 as explained in FIG. 1, further includes a controller 302 operably connected to the patient-side cart 110, the vision cart 120 and the surgeon master console 130. Further, the surgical instrument 140 includes a plurality of actuators 306 configured to manipulate the surgical instrument 140. In some implementations, the controller 302 is communicatively coupled to the patient-side cart 110, the vision cart 120 and the surgeon master console 130, via a communication network 308.
[0042] The controller 302 is configured to execute all necessary operations of the surgical robotic system 100. Examples of the processor 302 may include, but are not limited to, a microcontroller, a microprocessor, a central processing unit (CPU), a complex instruction set computing (CISC) processor, an application-specific integrated circuit (ASIC) processor, a reduced instruction set (RISC) processor, a very long instruction word (VLIW) processor, a digital signal processor (DSP), a field-programmable gate array (FPGA), or a data processing unit, and other processors or control circuitry.
[0043] The communication network 308 includes a medium (e.g., a communication channel) through which the to the patient-side cart 110, the vision cart 120 and the surgeon master console 130 communicates with the controller 302. The communication network 308 may be a wired or wireless communication network. Examples of the communication network 308 may include, but are not limited to, a Local Area Network (LAN), a wireless personal area network (WPAN), a Wireless Local Area Network (WLAN), a wireless wide area network (WWAN), a cloud network, a Long-Term Evolution (LTE) network, a plain old telephone service (POTS), a Metropolitan Area Network (MAN), and/or the Internet.
[0044] In an implementation, the robotic surgical system 100 further includes a sensing module 304 configured to track the position and orientation of the elongated shaft 220. In some implementations, the sensing module 304 is communicatively coupled to the controller 302 via the communication network 308.
[0045] The sensing module 304 refers to a subsystem configured to detect, measure, and track the position and orientation of the elongated shaft 220 during surgical operation. The sensing module 304 provides real-time spatial data that enables the controller 302 to maintain accurate alignment of the surgical instrument 140 with the fulcrum point and to adjust the plurality of actuators 306 accordingly. In some implementations, the sensing module 304 may include one or more position and orientation tracking devices configured to detect and monitor the spatial pose of the elongated shaft 220 in real time. Examples of the sensing module 304 may include, but are not limited to, optical sensors, electromagnetic trackers, inertial measurement units (IMUs), encoder-based systems, or combinations thereof. In some other implementations, the sensing module 304 may utilize magnetic field-based tracking systems that measure changes in electromagnetic fields to determine the position and orientation of the elongated shaft 220. In some implementations, the sensing module 304 may incorporate one or more inertial sensors (such as accelerometers and gyroscopes) embedded in the surgical instrument 140 or the robotic arm 112 for detecting angular velocity and linear acceleration.
[0046] FIG. 4 is a diagram illustrating the surgical instrument with assigned coordinate axes for performing kinematic calculation, in accordance with an embodiment of the present disclosure. FIG. 4 is described in conjunction with the elements of FIGs. 1 to 3. With reference to FIG. 4, there is shown the surgical instrument 140 with a fulcrum point 406 positioned on the elongated shaft 220. As illustrated in the embodiment of FIG. 4, the surgical instrument 140 includes the elongated shaft 220 with a fulcrum point 406 positioned along the length of the elongated shaft 220. The fulcrum point 406 represents a fixed spatial constraint in three-dimensional space through which the elongated shaft 220 must pass during all movements of the surgical instrument 140. In surgical applications, the fulcrum point 406 corresponds to the insertion point through which the surgical instrument 140 enters the patient's body. The fulcrum point 406 must be maintained as a fixed constraint to prevent unintended forces on the surrounding tissues, which may cause injury or enlarge the incision.
[0047] The surgical instrument 140 further includes a coordinate frame system essential for performing the inverse kinematics calculations. A reference coordinate frame with origin 410 is established at the jaw rotation axis of the grasping jaws 252. The reference coordinate frame is denoted by axes “XJ”, “YJ”, and “ZJ”, where “XJ” axis aligns with the rotation axis of the grasping jaws 252, the “ZJ” axis aligns with the centreline of the grasping jaws 252, and the “YJ” axis is determined using the right-hand rule to maintain orthogonality. The reference coordinate frame serves as the primary reference for calculating the jaw angle and determining the orientation of the end effector 210 during surgical manipulation.
[0048] Furthermore, a secondary coordinate frame is assigned at a pitch joint 408 of a pitch 402, which represents the articulation point where the distal end of the surgical instrument 140 can bend relative to the elongated shaft 220. The pitch coordinate frame is denoted by axes “XP”, “YP”, and “ZP”, where the “YP” axis aligns along the rotation axis of the pitch mechanism, the “ZP” axis aligns along the length of the pitch segment, and the XP axis is determined using the right-hand rule. The pitch joint 408 provides an additional degree of freedom beyond the pivoting of the elongated shaft 220 at fulcrum point 406, enabling more complex positioning of the end effector 210 inside the surgical space.
[0049] In operation, the controller 302 is configured to establish a reference coordinate frame with origin 410 at the jaw rotation axis of the surgical instrument 140. Initially, the controller 302 receives positional data from the sensing module 304, which tracks optical or electromagnetic markers positioned on the surgical instrument. Using the sensory input from the sensing module 304, the controller 302 identifies the physical location of the jaw rotation axis in three-dimensional space. Once located, the controller 302 constructs a cartesian coordinate system at the origin 410, defining the XJ axis to align with the physical rotation axis of the grasping jaws 252, the ZJ axis to align with the centreline of the grasping jaws 252, and the YJ axis to complete an orthogonal right-handed coordinate system.
[0050] After establishing the reference frame with origin 410 at the jaw rotation axis of the surgical instrument 140, the controller 302 identifies the fulcrum point 406 by analysing the trajectory of the elongated shaft 220 as it passes through the insertion point. The controller 302 determines the fulcrum point by tracking multiple positions of the elongated shaft 220 and determining their intersection point (for example, by using least-squares regression) to establish a mathematically precise constraint point in space. The fulcrum point 406 is continuously monitored during operation, with the controller 302 detecting any displacement that might occur and adjusting calculations accordingly. Similarly, the controller 302 locates the pitch joint 408 and establishes the coordinate frame for the pitch 402 based on the physical structure of the articulation mechanism. With the coordinate frames established, the controller 302 maintains a real-time mathematical model of the entire kinematic chain from the robotic arm 112 through the elongated shaft 220 to the end effector 210, enabling precise calculations of the required angles and positions.
[0051] The controller 302 is further configured to determine a jaw angle and a pitch angle of the end effector based on a selected position and a selected orientation of the end effector 210 received from the surgeon master console 130. In an implementation, determining the jaw angle comprises determining a normal vector to a plane containing vectors from the fulcrum point to the pitch joint and from the pitch joint to the end effector 210. The controller 302 calculates a first vector and a second vector, where the first vector extends from the fulcrum point 406 to the pitch joint 408, and the second vector extends from the pitch joint 408 to the end effector 210. The controller 302 then determine a cross product of the first vector and the second vector to generate a normal vector that is perpendicular to both the first vector and the second vector. The normal vector is subsequently normalized to obtain a unit normal vector having unit magnitude, to establish a reference direction perpendicular to the plane formed by the fulcrum point 406, the pitch joint 408 and the position of the robotic arm 112 in the kinematic chain of the surgical instrument 140.
[0052] Further, determining the jaw angle further includes calculating an angle between the longitudinal axis of the end effector 210 and the normal vector with reference to an established coordinate frame at the jaw rotation axis. The controller 302 represents the longitudinal axis of the end effector 210 as a unit vector aligned with the ZJ. The controller 302 determines a dot product between the longitudinal axis unit vector and the determined unit normal vector. Further, an application of an inverse cosine function to the dot product provides an angle value representing the spatial relationship between the longitudinal axis of the end effector 210 and the plane formed the normal vector with reference to an established coordinate frame at the jaw rotation axis.
[0053] Furthermore, determining the jaw angle deriving the jaw angle as the complementary angle to the angle between the longitudinal axis of the end effector and the normal vector. The controller 302 derives the jaw angle as a complementary angle to the angle between the longitudinal axis of the end effector and the normal vector with reference to an established coordinate frame at the jaw rotation axis Specifically, the controller 302 subtracts the angle between the longitudinal axis of the end effector and the normal vector with reference to an established coordinate frame at the jaw rotation axis from π/2 radians (90 degrees) to obtain the jaw angle. The complementary relationship accounts for the geometric configuration of the surgical instrument 140 and defines the rotation of the end effector 210 about the “XJ”. The resulting jaw angle value enables the controller 302 to generate appropriate control signals to the plurality of actuators 306.
[0054] In an implementation, determining the pitch angle includes projecting the longitudinal axis of the end effector 210 onto a plane containing the fulcrum point 406 and the elongated shaft 220 with reference to the established coordinate frame at the jaw rotation axis. The controller 302 first defines a plane where the plane contains the fulcrum point 406 and is parallel to the elongated shaft 220. Subsequently, the controller 302 mathematically projects the longitudinal axis vector of the end effector 210 onto the plane through vector decomposition techniques. The projection operation leads to a two-dimensional representation of the end effector 210 orientation within the defined plane. The controller 302 calculates projection by determining the component of the longitudinal axis vector that lies within the plane, the component of the longitudinal axis vector component being determined by subtracting the normal component from the original vector (Vorignal).
[0055] Further, determining the pitch angle includes determining vectors representing segments of the surgical instrument based on the physical dimensions of the segments of the surgical instrument 140. The controller 302 generates a first instrument segment vector extending from the fulcrum point 406 to the pitch joint 408, with magnitude corresponding to the physical length of the first instrument segment. Furthermore, the controller 302 generates a second instrument segment vector extending from the pitch joint 408 to the end effector 210, with magnitude corresponding to the physical length of the distal segment. The determined vectors incorporate the three-dimensional spatial coordinates of the respective points and the physical dimensions of the segments of surgical instrument 140 and establish a geometric model that accurately represents the surgical instrument 140 configuration. The physical dimensions are predetermined values obtained from the surgical instrument 140 specifications and stored in a memory accessible to the controller 302.
[0056] Determining the pitch angle further includes determining the pitch angle using the arctangent of the ratio between the magnitude of a first vector operation and a second vector operation of determined vectors. The controller 302 determines a cross product between the first instrument segment vector and the second instrument segment vector, thereby obtaining a vector perpendicular to the first instrument segment vector and the second instrument segment vector. The controller 302 subsequently determines a dot product between the first instrument segment vector and the second instrument segment vector, yielding a scalar value representing the projection of one vector onto the other. The controller 302 then calculates the magnitude of a cross-product of the first instrument segment vector and the second instrument segment vector and divides the magnitude of the cross-product vector value by the dot product scalar of the first instrument segment and the second instrument segment vector, thereby producing a ratio that represents the tangent of the pitch angle. Finally, the controller 302 applies an arctangent function to the ratio according to calculate the pitch angle.
[0057] The controller 302 is further configured to determine a position and orientation of an end of the at least one robotic arm about the fulcrum point 406 based on the spatial relationship between the fulcrum point 406, the pitch joint 408, and a position of the end effector 210. In an implementation, the controller is further configured to determine a position and an orientation of the end of the at least one robotic arm according to a predefined equation. In an implementation, the predefined equation defines a relationship between the position of the at least one robotic arm, the position of the fulcrum point, an effective length from the fulcrum point to the end effector 210, and a unit vector along the direction of the elongated shaft 220.
[0058] The predefined equation:
P={F– (Leff ×V)},
where “P” represents the position vector of the end of the at least one robotic arm in three-dimensional space,
“F” represents the position vector of the fulcrum point 406,
“Leff” represents an effective length from the fulcrum point 406 to the end effector 210, and
“V” represents a unit vector along the direction of the elongated shaft 220.
[0059] The controller 302 derives a unit vector “V” by normalizing the vector from the fulcrum point 406 to the pitch joint 408 to obtain a directional vector with unity magnitude. The effective length parameter “Leff” is calculated as the difference between the total length of the elongated shaft 220 and the length of the surgical instrument 140 extending beyond the fulcrum point 406, which ensures proper positioning of the robotic arm end relative to the fulcrum point 406.
[0060] The controller 302 implements the predefined equation by first establishing the spatial coordinates of the fulcrum point 406 based on sensory data from the sensing module 304. Subsequently, the controller 302 determines the direction of the elongated shaft 220 by determining a vector from the fulcrum point 406 to the pitch joint 408 and normalizing said vector to obtain the unit vector “V”. In an implementation effective length is the difference between a length of the elongated shaft 220, and a length of the surgical instrument extending beyond the fulcrum point 406. The controller 302 then calculates the effective length (Leff) by subtracting the portion of the surgical instrument 140 extending beyond the fulcrum point 406 from the total length of the elongated shaft 220, where extending portion is determined based on the desired position of the end effector 210. The controller 302 multiplies the effective length “Leff” with the unit vector “V” to obtain an effective product. The controller 302 further subtracts the effective product from the position of the fulcrum point 406 to obtain position vector for the end of at least one robotic arm. For determining the orientation of the end of the at least one robotic arm, the controller 302 establishes a local coordinate frame defined by three orthogonal unit vectors. The controller 302 designates the first axis of the coordinate frame as aligned with the unit vector “V” along the direction of the elongated shaft 220. To establish the second axis, the controller 302 determines a vector normal to the plane containing the fulcrum point 406 and the elongated shaft 220 by performing a cross-product operation between the unit vector “V” and a reference vector. The controller 302 subsequently normalizes a vector obtained using cross product operation to obtain a unit vector perpendicular to the plane of movement. To complete the orthogonal coordinate system, the controller 302 determines the third axis as the cross product of the first and second axes, to establish a right-handed coordinate system that fully characterizes the orientation of the end of the robotic arm.
[0061] The controller 302 is further configured to generate control signals to the plurality of actuators 306 and the at least one robotic arm such that the end effector 210 achieves the selected position and the selected orientation while the elongated shaft 220 always passes through the fulcrum point 406while ensuring that the elongated shaft 220 intersects the fulcrum point 406 with a lateral deviation not exceeding ±0.5 mm. Upon determining the jaw angle, the pitch angle, and the position and orientation of the end of the at least one robotic arm, the controller 302 translates the results of the jaw angle, the pitch angle, and the position and orientation of the end of the at least one robotic arm into appropriate electrical control signals compatible with the plurality of actuators 306 and servo motors of the robotic arm 112. The controller 302 employs a transformation algorithm that converts the mathematically derived angles and positions into corresponding voltages, currents, or pulse-width modulated signals that directly control the mechanical movement of the surgical instrument 140. The transformation algorithm may include scaling factors, calibration parameters, and compensation values specific to the particular actuator of the plurality of actuators 306 and motors employed in the robotic surgical system 100.
[0062] The controller 302 generates a first set of control signals directed to the plurality of actuators 306 responsible for manipulating the jaw angle and pitch angle of the end effector 210. The first set of control signals precisely regulates the angular position of the respective joints in accordance with the determined values. Concurrently, the controller 302 generates a second set of control signals directed to the servo motors of the robotic arm 112, thereby positioning the end of the at the robotic arm 112 determined position with the calculated orientation. The controller 302 synchronizes these dual sets of control signals to ensure coordinated movement of all components, preventing undesired transient configurations that might violate the fulcrum constraint during the movement trajectory.
[0063] To maintain the fulcrum constraint with high precision, the controller 302 implements a closed-loop control system that continuously monitors the actual position and orientation of the surgical instrument 140 via feedback from the sensing module 304. The controller 302 compares the sensed actual values with the determined target values, thereby generating error signals proportional to any deviation. The error signals are processed through proportional-integral-derivative (PID) control algorithms or other suitable control methodologies to produce corrective signals that minimize positional errors. The corrective signals are combined with the primary control signals to form composite control signals that drive the plurality of actuators 306 and the robotic arm 112 toward the desired configuration while automatically compensating for mechanical inaccuracies, backlash, or external forces.
[0064] To ensure the elongated shaft 220 passes through the fulcrum point 406 without lateral translation, the controller 302, in some examples, employs a constraint enforcement that continuously verifies the alignment of the elongated shaft 220 with the fulcrum point 406. The constraint enforcement determines the shortest distance between the fulcrum point 406 and the current axis of the elongated shaft 220, generating additional corrective signals whenever the distance exceeds a predetermined threshold. The corrective signals are superimposed on the primary control signals, leading to continuously steering the robotic arm 112 and the plurality of actuators 306 toward configurations that satisfy the fulcrum constraint, even during dynamic movement sequences. In bench-top validation, the controller 302 demonstrated real-time performance with an update rate of 1.5 kHz, achieving fulcrum constraint enforcement with lateral error maintained within ±0.3 mm, thereby exceeding the 1 kHz control loop benchmark for high-fidelity surgical applications.
[0065] The controller 302 further implements motion planning calculations that generate smooth trajectories between the current configuration and the target configuration, to prevent abrupt movements that might induce stress on the fulcrum point 406. In some implementations, the motion planning calculations determine time-parametrized paths through the configuration space, ensuring continuous first and second derivatives of position with respect to time, thus yielding smooth acceleration and deceleration profiles. The resulting control signals incorporate these temporal characteristics, producing fluid and precise movements of the surgical instrument 140 that maintain the fixed spatial constraint throughout the surgical procedure. The controller 302 achieves precise control of the surgical instrument 140, enabling accurate positioning and orientation of the end effector 210 while rigorously maintaining the fulcrum constraint.
[0066] In some implementations, the controller 302 comprises dedicated circuitry configured to perform real-time kinematic calculations using forward and inverse kinematic models stored in memory to translate between target positions of the end effector 210 and joint-space configurations of the robotic arm 112. In some implementations, the controller 302 includes a dedicated kinematic processor having multiple parallel processing units specifically designed to handle the computational demands of maintaining a fixed fulcrum constraint during surgical procedures. The dedicated kinematic processor may comprise vector calculation units, rotation matrix engines, and constraint enforcement modules implemented in application-specific integrated circuits (ASICs) to achieve computational efficiency substantially exceeding that of general-purpose processors. The specialized hardware components are interconnected via a high-speed data bus that facilitates rapid exchange of positional and orientation data between processing stages, enabling the system to maintain sub-millisecond response times during surgical manipulation.
[0067] When the surgeon master console 130 transmits a command to position the end effector 210, the controller 302 activates a multi-stage processing sequence within the dedicated circuitry. First, the target position processor converts the surgeon's input commands from the surgeon master console 130 coordinate system into the patient reference frame using a series of rotation and translation operations implemented in dedicated transformation hardware. The conversion of surgeon's input commands accounts for the relative positioning of the patient, the surgical site, and the viewing angle provided by the vision cart 120. Following coordinate transformation, the inverse kinematics engine determines the required jaw angle and pitch angle of the end effector 210 using the geometric approach.
[0068] The fulcrum constraint processor continuously evaluates the relationship between the elongated shaft 220 and the fulcrum point 406, generating correction vectors whenever the calculated trajectory would result in lateral translation of the shaft through the fulcrum point 406. The correction vectors are applied to the determined joint configurations before transmission to the actuator control module, ensuring that the fulcrum point 406 remains a fixed spatial constraint during all instrument movements. An actuator control module translates the determined joint configurations into specific control signals for each of the plurality of actuators 306. The translation accounts for the mechanical characteristics of each actuator, including response curves, backlash compensation, and dynamic friction profiles stored in the actuator parameter memory. The resulting control signals are transmitted via a real-time communication interface to the patient-side cart 110, where they drive the precise movements of the robotic arms and the surgical instrument 140.
[0069] During operation, the controller 302 continuously monitors the physical state of the robotic surgical system 100 through a sensor interface that receives position and force feedback from encoders and force sensors distributed throughout the system. The feedback is processed by the state estimation unit, which uses Kalman filtering implemented in dedicated estimation circuitry to maintain an accurate representation of the system's current configuration despite sensor noise and mechanical compliance.
[0070] Furthermore, the dedicated circuitry approach enables continuous enforcement of the fulcrum constraint at update rates exceeding 1000 Hz, preventing even momentary violations of the safety constraint. This represents a significant improvement over systems that rely on iterative software algorithms, which may exhibit variable performance under different computational loads or system states.
[0071] In an implementation, the controller 302 is further configured to continuously monitor the position of the fulcrum point 406 relatives to the established coordinate frame at the jaw rotation axis. Continuous monitoring of the position of the fulcrum point 406 by the controller 302 relative to the established coordinate frame at the jaw rotation axis is achieved through real-time geometric calculations and sensor feedback integration. The controller 302 receives updated position and orientation data from the sensing module 304, which tracks the spatial pose of the surgical instrument 140, including the elongated shaft 220 and its articulation relative to the patient’s body. Using the input, the controller 302 determines the spatial relationship between the fulcrum point 406 located at the trocar or entry site on the patient's body and the coordinate frame defined at the jaw rotation axis of the surgical instrument 140. The continuous feedback loop helps prevent unintended forces at the entry site, ensuring safety, precision, and stable tool behaviour throughout the surgical procedure.
[0072] In an implementation, based on monitoring the controller 302 is further configured to detect any displacement of the fulcrum point 406 and adjust the jaw angle and the pitch angle in real-time to maintain the fulcrum point 406 as the fixed spatial constraint during surgical manipulation. Detecting displacement of the fulcrum point 406 and adjusting the jaw angle and the pitch angle in real-time allows the robotic surgical system 100 to dynamically preserve the spatial constraint essential for minimally invasive surgical procedures. The continuous compensation ensures that the elongated shaft remains aligned through the insertion site, even when patient movement or tissue compliance alters position of the fulcrum point 406. By recalculating angular values on-the-fly, the controller 302 prevents the generation of unintended forces at the entry point, reducing trauma to surrounding tissues and enhancing procedural safety. The capability of the controller 302 also allows the robotic surgical system 100 to adapt to subtle anatomical shifts, providing greater control fidelity and improving overall surgical accuracy.
[0073] In an implementation, the controller 302 determines an orientation of the surgical instrument 140 by defining a first axis aligned with a direction vector of the elongated shaft 220. The controller 302 determines the direction vector by determining the spatial coordinates of two distinct points (i.e., the fulcrum point 406 and the pitch joint 408) along the elongated shaft 220. The controller 302 calculates a first vector (V1) from the fulcrum point 406 to the pitch joint 408. Subsequently, the controller 302 normalizes the first vector (V1) by dividing each component by magnitude the first vector to obtain a unit vector of the first vector (V1). The unit vector of the first vector (V1) constitutes the first axis of the coordinate system and aligns precisely with the longitudinal direction of the elongated shaft 220, providing a primary reference for the orientation of the surgical instrument 140.
[0074] The controller 302 further determines the orientation of the surgical instrument 140 by defining a second axis aligned with an unit vector perpendicular to the plane containing the fulcrum point 406 and the elongated shaft 220. To determine the unit vector perpendicular to the plane containing the fulcrum point 406 and the elongated shaft 220, the controller 302 first identifies a reference point external to the line defined by the elongated shaft 220. In some implementations, the controller 302 selects a reference point corresponding to the end effector 210 or another predefined point near a surgical site. The controller 302 then calculates a reference vector (Vref) from the fulcrum point 406 to the reference point. Subsequently, the controller 302 determines a cross product of the unit vector of the first vector (V1) and the reference vector (Vref) to obtain a second vector (V₂) The second vector (V2) is perpendicular to both the unit vector of the first vector (V1) and the reference vector (Vref), and consequently perpendicular to the plane containing the fulcrum point 406 and the elongated shaft 220. The controller 302 normalizes second vector (V₂) to obtain a unit vector of the second vector (V₂). The unit vector of the second vector (V₂) constitutes the second axis of the coordinate system. The second axis provides a reference direction perpendicular to the movement plane of the elongated shaft 220.
[0075] The controller 302 further determines the orientation of the surgical instrument 140 by defining a third axis as a cross-product of the first axis and the second axis to maintain an orthogonal coordinate system. The controller 302 determines the cross product of the first vector (V1) and the second vector (V2) and yields a third vector (V3). The third vector (V3) is perpendicular to both the first axis and the second axis. By virtue of the properties of the cross-product operation performed on the first vector and the second vectors, the third vector (V₃) is automatically a unit vector without requiring further normalization, provided the input vectors are precisely orthogonal. The third axis completes a right-handed orthogonal coordinate system.
[0076] The three-axis orthogonal coordinate system, thus established by the controller 302, fully characterizes the orientation of the surgical instrument 140 at any point during the surgical procedure. The orientation information of the surgical instrument 140, combined with the previously determined position data, enables the controller 302 to generate precise control signals to the plurality of actuators 306 and the robotic arm 112 to achieve the desired configuration while maintaining the fulcrum constraint. The mathematical approach advantageously provides a robust and computationally efficient method for tracking and controlling the orientation of the surgical instrument 140 throughout complex surgical manoeuvres, enhancing the precision and reliability of the robotic surgical system 100.
[0077] FIG. 5 is a flowchart illustrating a method for operating the robotic surgical system, in accordance with an embodiment of the present disclosure. FIG 5 is described in conjunction with elements from FIGs. 1 to 4. With reference to FIG.5, there is shown a flowchart illustrating a method 500 for operating the robotic surgical system 100. The method 500 includes steps 502 to 512.
[0078] At step 502, the method 500 includes receiving, at the controller 302, the selected position and the selected orientation of the end effector of the surgical instrument 140 from the surgeon master console 130. The reception of precise positional and orientational data from the surgeon master console 130 enables the robotic surgical system 100 to accurately interpret surgeon commands and translate them into executable instrument movements. The direct communication pathway between the surgeon master console 130 and the controller 302 ensures minimal latency in command transmission, facilitating real-time responsiveness during surgical procedures. The standardized data format for position and orientation information allows for consistent processing across different surgical scenarios and instrument configurations.
[0079] At step 504, the method 500 includes establishing a coordinate frame with origin at the jaw rotation axis of the surgical instrument 140. The establishment of the coordinate frame with origin at the jaw rotation axis provides a stable mathematical reference for all subsequent kinematic calculations. The jaw rotation axis serves as an optimal reference point because it remains fixed relative to the end effector during articulation movements, simplifying the computational complexity of angle calculations. The coordinate frame establishment creates a standardized spatial reference that enables consistent geometric relationships regardless of the position of the surgical instrument 140 within the patient's body.
[0080] At step 506, the method 500 includes determining the jaw angle and the pitch angle of the end effector 210 based on the selected position and the selected orientation of the end effector. The determination of jaw and pitch angles through geometric calculations ensures precise angular positioning of the end effector relative to the established coordinate frame. The calculation of the jaw angle and the pitch angle using vector-based mathematical operations provides computational efficiency and numerical stability compared to iterative approximation methods. The simultaneous determination of both angles enables coordinated movement of the end effector components, ensuring smooth and controlled articulation during surgical manipulation.
[0081] At step 508, the method 500 includes determining a position and an orientation of an end of at least one robotic arm about the fulcrum point based on a spatial relationship between the fulcrum point, the pitch joint, and the position of the end effector 210. The determination of robotic arm position and orientation through spatial relationship analysis ensures that the fulcrum constraint is maintained throughout all movements. The calculation based on the spatial relationship between multiple reference points provides geometric accuracy and prevents violations of the fixed pivot constraint. The consideration of the pitch joint position in the calculation enables proper articulation while maintaining the required alignment through the fulcrum point.
[0082] At step 510, the method 500 includes determining, in real time, commands related to joint space configurations using forward and inverse kinematic models that keep an elongated shaft of the surgical instrument intersecting the fulcrum point while the end effector moves toward the selected position and orientation. The real-time determination of joint space commands ensures continuous adherence to the fulcrum constraint during dynamic surgical movements. The utilization of both forward and inverse kinematic models provides comprehensive motion planning capabilities that account for all degrees of freedom in the robotic surgical system 100. The maintenance of elongated shaft 220 intersection with the fulcrum point prevents unintended forces at the insertion site, preserving tissue integrity and surgical safety.
[0083] At step 512, the method 500 includes generating control signals to a plurality of actuators 306 and the robotic arm to ensure the end effector achieves the selected position and the selected orientation while the elongated shaft passes through the fulcrum point without lateral translation. The generation of coordinated control signals to the plurality of actuators 306 enables simultaneous movement of all components of the robotic surgical system 100 while maintaining spatial constraints. The prevention of translation of all components of the robotic surgical system 100 at the fulcrum point eliminates the risk of tissue damage at the insertion site and maintains the integrity of the surgical access point.
[0084] The steps 502 to 512 are only illustrative, and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.
[0085] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure. 
, Claims:CLAIMS
We Claim:
1. A robotic surgical system (100) comprising:
a patient-side cart (110) comprising one or more robotic arms, wherein at least one robotic arm comprises a surgical instrument (140) comprising:
an elongated shaft (220) defining a longitudinal axis;
an end effector (210) disposed at a distal end of the elongated shaft (220); and
a plurality of actuators (306) configured to manipulate the surgical instrument (140);
a vision cart (120) configured to process and display images from a surgical site;
a surgeon master console (130) configured to control movement of the surgical instrument (140); and
a controller (302) operably connected to the patient-side cart (110), the vision cart (120) and the surgeon master console (130), wherein the controller (302) is configured to:
establish a coordinate frame with origin at a jaw rotation axis of the surgical instrument (140);
determine a jaw angle and a pitch angle of the end effector (210) based on a selected position and a selected orientation of the end effector (210) received from the surgeon master console (130);
determine a position and an orientation of an end of the at least one robotic arm about a fulcrum point (406) based on a spatial relationship between the fulcrum point (406), a pitch joint (408), and a position of the end effector (210); and
generate control signals to the plurality of actuators (306) and the at least one robotic arm to ensure the end effector (210) achieves the selected position and the selected orientation while the elongated shaft (220) passes through the fulcrum point (406) without lateral translation, wherein the controller (302) comprises dedicated circuitry configured to perform real-time kinematic calculations using forward and inverse kinematic models stored in a memory to translate between the selected positions of the end effector (210) and joint-space configurations of the at least one robotic arm (112).
2. The robotic surgical system (100) as claimed in claim 1, wherein determining the jaw angle comprises:
determining a normal vector to a plane containing vectors from the fulcrum point (406) to the pitch joint (408) and from the pitch joint (408) to the end effector (210);
calculating an angle between the longitudinal axis of the end effector (210) and the normal vector with reference to the coordinate frame at the jaw rotation axis; and
deriving the jaw angle as the complementary angle to the angle between the longitudinal axis of the end effector (210) and the normal vector.
3. The robotic surgical system (100) as claimed in claim 1, wherein determining the pitch angle comprises:
projecting the longitudinal axis of the end effector (210) onto a plane containing the fulcrum point (406) and the elongated shaft (220) with reference to the coordinate frame at the jaw rotation axis;
normalizing the projected vector to obtain a direction vector along the pitch axis;
determining vectors representing segments of the surgical instrument (140) based on physical dimensions of the segments of the surgical instrument (140); and
determining the pitch angle using the arctangent of the ratio between the magnitude of a first vector operation and a second vector operation of determined vectors.
4. The robotic surgical system (100) as claimed in claim 1, wherein the controller (302) is further configured to determine a position and an orientation of the end of the at least one robotic arm according to a predefined equation.
5. The robotic surgical system (100) as claimed in claim 4, wherein the predefined equation defines a relationship between the position of the at least one robotic arm, the position of the fulcrum point (406), an effective length from the fulcrum point to the end effector (210), and a unit vector along the direction of the elongated shaft (220).
6. The robotic surgical system (100) as claimed in claim 5, wherein the effective length is the difference between a length of the elongated shaft (220), and a length of the surgical instrument (140) extending beyond the fulcrum point (406).
7. The robotic surgical system (100) as claimed in claim 1, wherein the controller (302) determines an orientation of the surgical instrument (140) by:
defining a first axis aligned with a direction vector of the elongated shaft (220);
defining a second axis aligned with a unit vector perpendicular to the plane containing the fulcrum point (406) and the elongated shaft (220); and
defining a third axis as a cross product of the first axis and the second axis to maintain an orthogonal coordinate system.
8. The robotic surgical system (100) as claimed in claim 1, further comprising a sensing module (304) configured to track the position and orientation of the elongated shaft (220) and provide feedback to the controller (302) for maintaining the fulcrum point (406) as the fixed spatial constraint.
9. The robotic surgical system (100) as claimed in claim 1, wherein the controller (302) is further configured to continuously monitor the position of the fulcrum point (406) relative to the coordinate frame at the jaw rotation axis.
10. The robotic surgical system (100) as claimed in claim 9, wherein, based on monitoring the controller (302) is further configured to:
detect any displacement of the fulcrum point (406); and
adjust the jaw angle and the pitch angle in real-time to maintain the fulcrum as the fixed spatial constraint during surgical manipulation.
11. A method (500) for controlling a surgical instrument in a robotic surgical system (100), the method (500) comprising:
receiving, at a controller (302), a selected position and a selected orientation of an end effector (210) of a surgical instrument (140) from a surgeon master console (132);
establishing a coordinate frame with origin at a jaw rotation axis of the surgical instrument (140);
determining a jaw angle and a pitch angle of the end effector (210) based on the selected position and the selected orientation of the end effector (210);
determining a position and an orientation of an end of at least one robotic arm about a fulcrum point based on a spatial relationship between the fulcrum point, a pitch joint, and a position of the end effector (210);
determining, in real time, commands of joint space configurations using forward and inverse kinematic models that keep an elongated shaft (220) of the surgical instrument (140) intersecting the fulcrum point while the end effector (210) moves toward the selected position and orientation; and
generating control signals to a plurality of actuators (306) and the at least one robotic arm (112) to ensure the end effector (210) achieves the selected position and the selected orientation while the elongated shaft (220) passes through the fulcrum point without lateral translation.
12. A non-transitory computer readable medium storing instruction that, when executed by a controller (302) of a robotic surgical system (100), cause the controller (302) to:
receive a selected position and a selected orientation of an end effector (210) of a surgical instrument from a surgeon master console (132);
establish a coordinate frame with origin at a jaw rotation axis of the surgical instrument (140);
determine a jaw angle and a pitch angle of the end effector (210) based on the selected position and the selected orientation of the end effector (210);
determine a position and an orientation of an end of at least one robotic arm about a fulcrum point based on a spatial relationship between the fulcrum point, a pitch joint, and a position of the end effector (210);
determine, in real time, control commands using forward and inverse kinematic models to maintain an elongated shaft (220) of the surgical instrument (140) intersecting the fulcrum point while the end effector (210) moves toward the selected position and the selected orientation; and
generate control signals based on the control commands to a plurality of actuators (306) and the at least one robotic arm to ensure the end effector (210) achieves the selected position and the selected orientation while the elongated shaft (220) passes through the fulcrum point without lateral translation.