Description:TECHNICAL FIELD
The present disclosure relates to rotary series elastic sensing actuators.
BACKGROUND
Elastic actuators use elastic elements for achieving compliance in motion control, particularly in safety-critical applications involving human-machine or robot interactions. Such elastic actuators play a dual role, serving not only as a means to control motion but also as torque sensors. In this regard, a series elastic actuator (SEA) has been developed, wherein an elastic element is strategically placed in series with the link (i.e., a shaft) transferring power from a prime mover to a load. Specifically, in rotary systems, the elastic element in the rotary series elastic actuator (rSEA) takes the form of a torsion spring of known stiffness, wherein the deflection of this spring is a measure of torque. The rSEA also has the added benefit of providing inherent mechanical compliance in safety-critical scenarios.
However, challenges persist in torque measurement accuracy of traditional rSEAs due to limitations such as non-linearity and hysteresis due to variations in the structure of the spring system and drift in its material properties. To address the non-linearity of traditional rSEAs , custom planar symmetric torsional spring designs have been proposed, offering improved linearity in their deflection as a measure of torque. Yet, these designs necessitate use of additional external sensors, such as encoders, to accurately measure deflection. Also, the use of external encoders as a deflection measure for rSEAs has limited torque measurement accuracy. Thus, existing rSEAs and planar rSEAs depend on external sensing, which introduces limitations in terms of deflection measurement accuracy and torque sensing linearity.
There are other ways to measure torque in a rotary system. These techniques however lack the inherent mechanical compliance offered by rSEAs. For example, a PCB based torque sensor has been proposed with a strain gauge torque sensor etched on a PCB disc. The PCB disc has no cutout pattern and its torsional stiffness is dictated only by its thickness, diameter and material choice. The PCB disc therefore has limited compliance/energy storage capability and is therefore a stiff torque sensor. Furthermore, a PCB-based bending force sensor employing strain gauges etched on the PCB substrate is employed as a torque sensor. However, this PCB-based bending force sensor is stationary and a non-rotary device which measures cantilever force along a single axis. Thus, the PCB-based bending force sensor is a stiff torque sensor. These stiff torque sensors when used in closed-loop controllers, lack shock tolerance and inherent mechanical compliance. Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks.
SUMMARY
The present disclosure seeks to provide rotary series elastic sensing actuators. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art.
In an aspect, an embodiment of the present disclosure provides a rotary series elastic sensing actuator comprising:
a printed circuit board (PCB) comprising:
a substrate;
spiral spring elements integral to the substrate to form a planar spring, the spiral spring elements arranged in a spaced apart and concentric manner;
one or more first sensors embedded on the substrate and adjacent to the spiral spring elements; and
a processor communicably coupled to the one or more first sensors, wherein when the rotary series elastic sensing actuator is in use, the processor is configured to:
receive a sensor data, from the one or more first sensors, indicative of a deflection experienced by the spiral spring elements, based on a distance between the spiral spring elements when the PCB is subjected to a rotary movement; and
process the sensor data to determine a measurement of torque transmitted from a prime mover to a load.
Optionally, the spiral spring elements are formed using a material forming the substrate.
Optionally, the material is any one of: a glass-reinforced epoxy substrate, an aluminium substrate, a copper substrate.
Optionally, a configuration of the spiral spring elements is based on one or more structural parameters associated with at least one of: a spiral angle between the spiral spring elements, a helical pitch, a spiral width of the spiral spring elements, a quantity of the spiral spring elements.
Optionally the PCB is one of a single layer PCB or a multi-layer PCB, and wherein when the PCB is the multi-layer PCB, a stiffness of the spiral spring elements is based on a number of layers and materials forming the multi-layer PCB.
Optionally, the rotary series elastic sensing actuator further comprising:
one or more second sensors embedded on the substrate in a spatially-distributed manner and operable to measure temperature values across the substrate; and
one or more third sensors embedded on the substrate and operable to measure an angular displacement of the PCB,
wherein when the rotary series elastic sensing actuator is in use, the processor is further configured to receive sensor data from at least one of the one or more second or third sensors to determine the measurement of torque that is compensated for at least one of: a change in stiffness of the substrate based on the temperature values across the substrate, a rotational angle of the PCB based on the angular displacement of the PCB.
Optionally, the processor is further configured to fuse sensor data received from the at least one of: the one or more second sensors, the one or more third sensors, with the sensor data received from the one or more first sensors, by employing a sensor data fusion algorithm, to determine a measurement of torque.
Optionally, the rotary series elastic sensing actuator further comprising a power delivery system embedded on the substrate, wherein the power delivery system is configured to deliver power to at least the one or more first sensors and the processor, when in use, and wherein the power delivery system comprises at least one of: a wireless means of delivering power, a wired means of delivering power.
Optionally, the rotary series elastic sensing actuator further comprising a communication interface embedded on the substrate, wherein the communication interface configured to receive the measurement of torque from the processor to communicate to a central processing unit operable to control operation of the rotary series elastic sensing actuator.
Optionally, the PCB further comprises a plurality of holes for enabling coupling of the PCB with the prime mover and the load.
BRIEF DESCRIPTION OF THE DRAWINGS
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 skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
FIG. 1A illustrates an architecture of a rotary series elastic sensing actuator, and referring to FIG. 1B, there is illustrated an architecture of a printed circuit board (PCB), in accordance with an embodiment of the present disclosure; and
FIG. 2 illustrates a packaging of the rotary series elastic sensing actuator of FIG. 1A, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION
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.
The rotary series elastic actuator comprises spiral spring elements that form a planar spring, which enables compliance in rotating joints for safe operation in robotic applications. Furthermore, one or more first sensors are integrated within a printed circuit board (PCB) of the rotary series elastic actuator, thereby eliminating a need for external sensors to measure distance between the spiral spring elements when the PCB is subjected to a rotary movement. A design of the rotary series elastic actuator is such that it allows deterministic stiffness control, collection of sensor data by the one or more first sensors in an integrated manner and/or a distributed manner, and also measures the torque accurately when compared to conventional rotary series elastic actuators. Furthermore, the arrangement of the spiral spring elements provides inherent mechanical compliance. The rotary series elastic actuator is connected in series between the prime mover and the load. Advantageously, such arrangement makes the rotary series elastic actuator ideal when high accuracy and/or repeatability is required. Furthermore, a processor comprised in the rotary series elastic actuator is configured in such a manner that said processor processes sensor data to determine measurement of torque for a full load, i.e., a full-load torque. Advantageously, the rotary series elastic actuator is packaged as a modular unit that can be connected between any prime mover (of rated specification) and the load, wherein such modular unit offers compliance and/or safety control when in use.
Referring to FIG. 1A, there is illustrated an architecture of a rotary series elastic sensing actuator 100, and referring to FIG. 1B, there is illustrated an architecture of a printed circuit board (PCB) 102, in accordance with an embodiment of the present disclosure. In FIG. 1A, the rotary series elastic sensing actuator 100 comprises the PCB 102 comprising a substrate and spiral spring elements 104 integral to the substrate to form a planar spring, one or more first sensors (depicted as a first sensor 106A) embedded on the substrate and adjacent to the spiral spring elements 104, and a processor 108 communicably coupled to the first sensor 106A. The processor 108 is configured to: receive a sensor data, from the first sensor 106A, indicative of a deflection experienced by the spiral spring elements 104, based on a distance between the spiral spring elements 104 when the PCB 102 is subjected to a rotary movement; and process the sensor data to determine a measurement of torque transmitted from a prime mover to a load. Optionally, the rotary series elastic sensing actuator 100 further comprises one or more second sensors (depicted as second sensora 106B) embedded on the substrate in a spatially-distributed manner and operable to measure temperature values across the substrate, and one or more third sensors (depicted as a third sensor 106C) embedded on the substrate and operable to measure an angular displacement of the PCB 102. Optionally, the rotary series elastic sensing actuator 100 further comprises a power delivery system 110 embedded on the substrate. Optionally, the rotary series elastic sensing actuator 100 further comprises a communication interface 112 embedded on the substrate. Optionally, the rotary series elastic sensing actuator 100 further comprises a plurality of holes (depicted as holes 114A, 114B, 114C, 114D) for enabling coupling of the PCB 102 with the prime mover and the load.
In FIG. 1B, the PCB 102 comprises the substrate 116 and the spiral spring elements 104 integral to the substrate 116 to form a planar spring, the spiral spring elements 104 arranged in a spaced apart and concentric manner.
Throughout the present disclosure, the term "rotary series elastic actuator" refers to a specialised type of actuator that incorporates an elastic element between the prime mover and the load. An elasticity of the elastic element facilitates measurement of torque which is produced by the prime mover. The elastic element stores and releases potential energy as the prime mover rotates. This allows the rotary series elastic actuator 100 to absorb shock or vibrations while measuring torque, thus improving safety in an event of overloading or power failure. The rotary series elastic actuator 100 is used for applications, not limited to, robotic manipulation, haptic feedback devices, and prosthetic limbs.
Throughout the present disclosure, the "printed circuit board" provides a platform for the arrangement and interconnection of electronic components. Such platform is compact and flexible, which integrates mechanical elements (i.e., the spiral spring elements) and the electronic components (i.e., the one or more first sensors 106A, the processor 108). Moreover, the PCB 102 facilitates seamless communication between the one or more first sensors 106A and the processor 108, enabling real-time torque measurement during rotary movement. Notably, the spiral spring elements 104 are embedded within the substrate 116 to form a planar spring. The spiral spring elements 104 are deposited on the substrate 116 in a protruding manner resembling walls. This makes the rotary series elastic sensing actuator 100 a planar rotary spring that is elastic by definition within operating conditions of said rotary series elastic sensing actuator 100.
Herein, forming the planar spring enables a uniform deflection across the PCB 102 during rotary movement. This uniform deflection is beneficial for consistent and predictable mechanical behaviour, thereby contributing to a precision of torque measurements. The spiral spring elements 104 are integral to the PCB 102, thereby forming a cohesive structure. Furthermore, arranging the spiral spring elements 104 in a spaced-apart and concentric manner enhances the mechanical characteristics of the planar spring, by distributing forces evenly and providing a balanced response to external stimuli, such as the rotary movement. Optionally, the spiral spring elements 104 could be directly fabricated onto the PCB 102 using manufacturing techniques, for example, such as laser ablation, chemical etching. Such manufacturing techniques are well-known in the art.
Optionally, the spiral spring elements 104 are formed using a material forming the substrate 116. In this regard, the material used for forming the substrate 116 provides a structural foundation for the PCB 102 while simultaneously being shaped into the spiral spring elements. Herein, the material for forming the substrate 116 is selected based on mechanical properties (for example, such as elasticity, flexibility, resilience, fatigue resistance, and density) of said material, which are also essential for a functionality of the spiral spring elements. The material forming the substrate 116 is processed and manipulated to create spiral shapes necessary for constructing the spiral spring elements. A technical effect of forming the spiral spring elements 104 using the material forming the substrate 116 is that it allows integrated sensing of angular deformation and hence the measurement of torque in a compact form factor. Beneficially, this enables multi-modal distributed measurement of the torque for robust safety critical applications.
Optionally, the material is any one of: a glass-reinforced epoxy substrate, an aluminium substrate, a copper substrate. Herein, each material offers distinct properties contributing to a performance of the rotary series elastic sensing actuator 100. The glass-reinforced epoxy substrate is a combination of epoxy resin with glass fibres, wherein the glass-reinforced epoxy substrate provides at least one of: electrical insulation, mechanical strength, dimensional stability, chemical resistance, to the PCB 102. Examples of the glass-reinforced epoxy substrate may include, but are not limited to, Flame Retardant 1 (FR1), FR2, FR3, FR4, and FR5. The aluminium substrate has a base material made of aluminium, wherein the aluminium substrate provides low density, high thermal conductivity, offers lightweight design, mechanically robust, and has efficient heat dissipation. The copper substrate has a base material made of copper, wherein the copper substrate provides high electrical conductivity, is ductile and malleable, and is corrosion resistant. The material is selected based on a particular at least one of: mechanical requirement (e.g. stiffness, torque measurement range), electrical requirement, thermal requirement of the rotary series elastic sensing actuator 100. Beneficially, the PCB 102 is manufactured based on requirement of a user, wherein the material used for manufacturing the substrate 116 as well as the spiral spring elements 104 facilitates optimization of an overall functionality and reliability of the rotary series elastic sensing actuator 100.
Optionally, a configuration of the spiral spring elements 104 is based on one or more structural parameters associated with at least one of: a spiral angle between the spiral spring elements 104, a helical pitch, a spiral width of the spiral spring elements 104, a quantity of the spiral spring elements 104. Herein, the one or more structural parameters influence the configuration of the spiral spring elements 104. When the one or more structural parameters are adjusted, mechanical properties of the rotary series elastic sensing actuator 100 can be customized. Herein, the term "spiral angle" refers to an angle at which the spiral spring elements 104 wind around a centre of the substrate 116. The spiral angle impacts at least one of: a flexibility, a torque sensitivity, of the spiral spring elements 104. Furthermore, the spiral angle influences an overall shape and behaviour of the spiral spring elements 104 during deflection. It will be appreciated that the spiral angle is directly related to the flexibility of the spiral spring elements 104, i.e., larger the spiral angle, more flexible are the spiral spring elements 104. It will also be appreciated that spiral angle is indirectly related to the torque sensitivity of the spiral spring elements 104, i.e., larger the spiral angle, less torque sensitivity of the spiral spring elements 104.
Moreover, the term "helical pitch" refers to a spacing between turns of the spiral spring elements 104, wherein such spacing influences how much the spiral spring elements 104 can any one of: stretch, compress, when subjected to torque. The helical pitch affects an axial displacement per revolution of the spiral spring elements 104. It will be appreciated that the helical pitch is inversely related to compression, i.e., larger the helical pitch, lesser will be the compression of the spiral spring elements 104. It will also be appreciated that the helical pitch is inversely related to stiffness of the spiral spring elements 104, i.e., larger the helical pitch, lower will be the stiffness of the spiral spring elements 104.
Moreover, the term "spiral width" refers to a thickness of the spiral spring elements 104, which directly affects an overall stiffness and strength of the spiral spring elements 104. It will be appreciated that when the spiral spring elements 104 are wide, the overall stiffness and strength of the spiral spring elements 104 is high. Furthermore, the phrase "quantity of the spiral spring elements" refers to a number of individual spiral spring elements 104 formed on the substrate 116 of the PCB 102. The quantity of the spiral spring elements 104 impacts an overall mechanical properties of the rotary series elastic sensing actuator 100.
A technical effect of configuring the spiral spring elements 104 based on the one or more structural parameters in such a manner is that the spiral spring elements 104 can be configured based on requirements of the user. In one exemplary scenario, when the rotary series elastic sensing actuator 100 may be implemented for high-torque applications, the spiral width is large while the helical pitch is small. In another exemplary scenario, when the rotary series elastic sensing actuator 100 may be implemented to be sensitive to small torque changes, the quantity of the spiral spring elements 104 may be increased, the spiral angle may be large, and the helical pitch may be large. In yet another exemplary scenario, when there is weight and space constraints, the quantity of the spiral spring elements 104 may be decreased.
Optionally, the PCB 102 is one of a single layer PCB or a multi-layer PCB, and wherein when the PCB 102 is the multi-layer PCB, a stiffness of the spiral spring elements 104 is based on a number of layers and materials forming the multi-layer PCB. In this regard, the stiffness of the spiral spring elements 104 is used to determine a resistance to deformation when torque is applied to the PCB 102. Herein, the single layer PCB comprises a single layer of the substrate 116, and the multi-layer PCB comprises multiple layers of the substrate 116. When the PCB 102 is the multi-layer PCB, the number of layers in said multi-layer PCB directly affects an overall thickness and a structural rigidity of the PCB 102. In this regard, a thickness and the stiffness of the multi-layer PCB increases as the number of layers is increased. Furthermore, the stiffness of the spiral spring elements 104 depends on a stiffness of the materials forming the multi-layer PCB. Herein, each layer has particular properties of the material, for example, such as Young's modulus, which directly affects the stiffness of the multi-layer PCB. A technical effect of the PCB 102 being one of the single layer PCB or the multi-layer PCB, the stiffness of the PCB 102 and the spiral spring elements 104 can be controlled to achieve the mechanical properties of the rotary series elastic sensing actuator 100 as per requirement.
Optionally, the PCB 102 further comprises a plurality of holes 114A-D for enabling coupling of the PCB 102 with the prime mover and the load. The plurality of holes 114A-D provides mechanical points of attachment for securing the rotary series elastic sensing actuator 100 to the prime mover and the load. Herein, the prime mover. The plurality of holes 114A-D comprises outer coupling holes in proximity to periphery of the PCB 102, and an inner coupling hole at a centre of the PCB 102. Herein the outer coupling holes couples the PCB 102 to the prime mover, and the inner coupling hole couples the PCB 102 to the load. The plurality of holes 114A-D are strategically positioned to align with corresponding mounting points on the prime mover and the load. A technical benefit of the PCB 102 comprising the plurality of holes 114A-D is that it ensures transmission of motion from the prime mover to the load through the actuator 100, in an efficient manner.
The one or more first sensors 106A are embedded on the substrate 116 and adjacent to the spiral spring elements 104. In this regard, the one or more first sensors 106A are in proximity to the spiral spring elements 104 to ensure a close and direct connection between the one or more first sensors 106A and the spiral spring elements 104 of the rotary series elastic sensing actuator 100. This enables the one or more first sensors 106A to detect and measure any deflection or changes in the spiral springs elements 104, and provide feedback on the mechanical behaviour of the rotary series elastic sensing actuator 100. This feedback is provided in real time or near-real time. Optionally, the one or more first sensors 106A takes form of at least one of: distributed circuit elements, etched surface patterns, strain gauges, proximity sensors, Micro Electro-Mechanical Systems (MEMS) sensors, Inertial Measurement Units (IMUs). Optionally, when the PCB 102 is the multi-layer PCB, the one or more first sensors 106A are embedded on top of a top-most layer of the multi-layer PCB, integrated between layers of the multi-layer PCB, and/or at bottom of a bottom-most layer of the multi-layer PCB.
The processor 108 is communicably coupled to the one or more first sensors 106A. The processor 108 could be implemented as any one of: a microprocessor, a microcontroller, or a controller. As an example, the processor 108 could be implemented as an application-specific integrated circuit (ASIC) chip or a reduced instruction set computer (RISC) chip.
The one or more first sensors 106A is configured to collect sensor data, and send the sensor data to the processor 108. The collection of the sensor data is based on an arrangement and movement of the spiral spring elements 104, when subjected to torque. In this regard, the one or more first sensors 106A is configured to detect changes in the distance between the spiral spring elements 104 as the PCB 102 undergoes rotary movement. In other words, when the PCB 102 undergoes the rotary movement and torque is applied, the spiral spring elements 104 deflect, i.e., said spiral spring elements 104 twist, which increases a gap between the spiral spring elements 104. Hence, this deflection causes a change in distance between the spiral spring elements 104, which is detected as the sensor data by the one or more first sensors 106A. The processor 108 is then configured to determine the deflection experienced by the spiral spring elements 104. Herein, the sensor data is any one of: an analog sensor data, a digital sensor data. In this regard, the analog sensor data comprises values of distance between the spiral spring elements 104 when the PCB 102 is subjected to a rotary movement, whereas the digital sensor data comprises discrete values of distance between the spiral spring elements 104.
Optionally, the one or more first sensors 106A is implemented as at least one of: a capacitive sensor, an optical sensor, a piezoresistive sensor, a strain gauge. When the one or more first sensors 106A is implemented as the capacitive sensor, a capacitance between the walls of the spiral spring elements 104 changes as the distance between the spiral spring elements 104 increases. When the one or more first sensors 106A is implemented as the optical sensor, the optical sensor emits a light beam. Herein, a path of the light beam could be altered due to the change in the distance between the spiral spring elements 104, thereby detecting a signal variation. When the one or more first sensors 106A is implemented as the piezoresistive sensor, the piezoresistive sensor experiences less pressure due to an increase in the distance between the spiral spring elements 104, thereby causing a change in the resistance of the piezoresistive sensor. When the one or more first sensors 106A is implemented as the strain gauge, due to a change in the distance between the spiral spring elements 104, the substrate 116 is deformed around said spiral spring elements 104, which results in a measurable strain reading.
The processor 108 is configured to determine a measurement of torque by processing the sensor data, wherein the torque is linear to the distance between the spring elements 104. Herein, the torque is transmitted from the prime mover to the load, wherein the prime mover initiates the rotary movement and the load experiences said rotary movement. The processor 108 could use any one of: a mathematical formula, a function, an algorithm to determine the measurement of torque, wherein the change in distance between the spiral spring elements 104 is translated to a force applied to the spiral spring elements 104. Optionally, the processor 108 is further configured to determine another distance from a location where the torque is applied to the spiral spring elements 104, and uses this information along with the force to determine the measurement of torque.
Optionally, the rotary series elastic sensing actuator 100 further comprises:
one or more second sensors 106B embedded on the substrate 116 in a spatially-distributed manner and operable to measure temperature values across the substrate 116; and
one or more third sensors 106C embedded on the substrate 116 and operable to measure an angular displacement of the PCB 102,
wherein when the rotary series elastic sensing actuator 100 is in use, the processor 108 is further configured to receive sensor data from at least one of the one or more second or third sensors 106C to determine the measurement of torque that is compensated for at least one of: a change in stiffness of the substrate 116 based on the temperature values across the substrate 116, a rotational angle of the PCB 102 based on the angular displacement of the PCB 102.
Herein, the one or more second sensors 106B are embedded in the spatially-distributed manner to capture variations in temperature values at different points on the substrate 116, effectively covering an entire surface of the substrate 116. In this regard, the substrate 116 may experience non-uniform temperature distribution due to at least one of: environmental conditions around the rotary series elastic sensing actuator 100, localized heating effects on the PCB 102. Such non-uniform temperature distribution influences the mechanical properties of the material of the substrate 116, thereby affecting the stiffness of the substrate 116. The processor 108 is configured to calculate an average temperature by considering the sensor data from the one or more second sensors 106B, to determine an overall temperature affecting the spiral spring elements 104. This facilitates the processor 108 to map the temperature values with the different points on the substrate 116, to determine how much the stiffness of the substrate 116 changes at the different points due to the variations in the temperature values. Subsequently, when determining the measurement of torque, the processor 108 is configured adjust the stiffness for each spiral spring element based on its location on the substrate 116 and corresponding temperature value. Such adjustment compensates for change in stiffness of the substrate 116 based on the temperature values. Examples of the one or more second sensors 106B may include, but are not limited to, thermistors, resistance temperature detectors (RTDs), and thermocouples.
Moreover, the one or more third sensors 106C are embedded in close proximity to the PCB 102 to measure the angular displacement of the PCB 102, when the PCB 102 is subjected to the rotary movement. The one or more third sensors 106C move along with the rotary movement of the PCB 102, hence said one or more third sensors 106C remain consistently aligned with the rotational movement of the PCB 102 and continuously measure the angular displacement of the PCB 102 during its rotation. The processor 108 is configured to compensate for a misalignment introduced due to the angular displacement of the PCB 102 by knowing the rotational angle of the PCB 102, and thereby determine the measurement of torque. Examples of the one or more third sensors 106C may include, but are not limited to, Piezoresistive sensors, Micro Electro-Mechanical Systems (MEMS) accelerometers, Magnetometers, and Inertial Measurement Unit (IMU).
Optionally, the processor 108 is further configured to fuse sensor data received from the at least one of: the one or more second sensors 106B, the one or more third sensors 106C, with the sensor data received from the one or more first sensors 106A, by employing a sensor data fusion algorithm, to determine a measurement of torque. Herein, the sensor data fusion algorithm combines information from any one of: the one or more first sensors 106A and the one or more second sensors 106B; the one or more first sensors 106A the one or more third sensors 106C; the one or more first sensors 106A, the one or more second sensors 106B and the one or more third sensors 106C, to create a comprehensive understanding of the rotary movement of the PCB 102. In this regard, the sensor data fusion algorithm assigns a weight to the sensor data received from each of the one or more first sensors 106A, the one or more second sensors 106B, and the one or more third sensors 106C. Subsequently, the sensor data fusion algorithm maps the sensor data with the deflection experienced by the spiral spring elements 104 and/or the rotary movement of the PCB 102. Consequently, the measurement of torque is determined which is a single value, since such measurement of torque incorporates the sensor data from all available sensors (i.e., the one or more first sensors 106A, the one or more second sensors 106B and the one or more third sensors 106C) and compensates for potential limitations.
Optionally, the rotary series elastic sensing actuator 100 further comprises a power delivery system 110 embedded on the substrate 116, wherein the power delivery system 110 is configured to deliver power to at least the one or more first sensors 106A and the processor 108, when in use, and wherein the power delivery system 110 comprises at least one of: a wireless means of delivering power, a wired means of delivering power. In this regard, the power delivery system 110 is configured to generate signals (namely, voltage signals and/or current signals) to deliver the power. Optionally, the wired means of delivering power comprises a combination of a pair of slip rings and mating tracks deposited on the substrate 116 in a concentric manner, wherein when the rotary series elastic sensing actuator 100 is in use, the pair of slip rings and mating tracks receives power from the prime mover which is delivered to at least the one or more first sensors 106A and the processor 108. When the power delivery system 110 comprises the wireless means of delivering power, the power is delivered via wireless technologies (for example, such as electromagnetic induction, radiofrequency energy transfer). Such wireless technologies are well-known in the art. When the power delivery system 110 comprises the wired means of delivering power, the power is delivered via physical connections (for example, such as cables, conductive pathways). Optionally, the power delivery system 110 is further configured to deliver power to the one or more second sensors 106B, one or more third sensors 106C, and the communication interface 112. A technical effect of configuring the power delivery system 110 in such a manner is that this allows adapting the rotary series elastic sensing actuator 100 based on different applications and preferences of the user. Optionally, the power delivery system 110 is further configured to deliver power to at least one of: the one or more second sensors 106B, and the one or more third sensors 106C.
Optionally, the power delivery system 110 employs a power conditioning circuitry to ensure a stable and reliable delivery of the power to at least the one or more first sensors 106A and the processor 108. The power conditioning circuitry is employed to at least one of: stabilize the voltage signal supplied to the one or more first sensors 106A and the processor 108, regulate the current signal supplied to the one or more first sensors 106A and the processor 108, filter electrical noise and interference from the power delivery system 110, safeguard against spikes or surges in the voltage signal.
Optionally, rotary series elastic sensing actuator 100 further comprises a communication interface 112 embedded on the substrate 116, wherein the communication interface 112 configured to receive the measurement of torque from the processor 108 to communicate to a central processing unit operable to control operation of the rotary series elastic sensing actuator 100. Herein, the term "communication interface" refers to an electronic circuit that provides a physical or virtual interface that is configured to facilitate data communication between at least the one or more first sensors 106A and the processor 108. The communication interface 112 is at least one of: a set of hardware components, a set of software components. The communication interface 112 comprises at least one of: a wired communication interface, a wireless communication interface. When the communication interface 112 comprises the wired communication interface, conductive pathways are embedded on the substrate 116 to transmit information. The communication interface 112 carries out communication via any number of known protocols, including, but not limited to, Internet Protocol (IP), Wireless Access Protocol (WAP), Frame Relay, or Asynchronous Transfer Mode (ATM). Examples of the wired communication interface may include, but are not limited to, Ethernet, Universal Serial Bus (USB), and serial ports. When the communication interface 112 comprises the wireless communication interface, to transmit data at least electromagnetically. Examples of the communication interface 112 may include, but are not limited to, Bluetooth®, Wi-Fi, and Near Field Communication (NFC).
Moreover, the communication interface 112 establishes a connection with the central processing unit using the chosen protocol. Herein, the central processing unit is of a system which is responsible for controlling an entire operation of the system, of which the rotary series elastic sensing actuator 100 is a part. The communication interface 112 communicates the measurement of torque to the central processing unit in real time or near-real time, to determine a current state of the rotary series elastic sensing actuator 100. Thereafter, the central processing unit makes decisions based on the measurement of torque regarding the operation of the rotary series elastic sensing actuator 100 and the system. For example, the central processing unit may adjust at least one of: a power, a speed, a direction of the rotary series elastic sensing actuator 100 based on the measurement of torque. A technical effect of communicating the measurement of torque to the central processing unit in such a manner is to synchronize the rotary series elastic sensing actuator 100 with constituents of the system, to promote a controlled operation of the system.
Referring to FIG. 2, there is illustrated packaging of the rotary series elastic sensing actuator 100 of FIG. 1A, in accordance with an embodiment of the present disclosure. The rotary series elastic sensing actuator 100 is packaged as a modular unit 200, wherein the modular unit 200 has a first end 202A and a second end 202B. The first end 202A is connected to the prime mover, and the second end 202B is connected to the load.
, Claims:CLAIMS
What is claimed is:
1. A rotary series elastic sensing actuator comprising:
a printed circuit board (PCB) comprising:
a substrate;
spiral spring elements integral to the substrate to form a planar spring, the spiral spring elements arranged in a spaced apart and concentric manner;
one or more first sensors embedded on the substrate and adjacent to the spiral spring elements; and
a processor communicably coupled to the one or more first sensors, wherein when the rotary series elastic sensing actuator is in use, the processor is configured to:
receive a sensor data, from the one or more first sensors, indicative of a deflection experienced by the spiral spring elements, based on a distance between the spiral spring elements when the PCB is subjected to a rotary movement; and
process the sensor data to determine a measurement of torque transmitted from a prime mover to a load.
2. The rotary series elastic sensing actuator as claimed in claim 1, wherein the spiral spring elements are formed using a material forming the substrate.
3. The rotary series elastic sensing actuator as claimed in claim 2, wherein the material is any one of: a glass-reinforced epoxy substrate, an aluminium substrate, a copper substrate.
4. The rotary series elastic sensing actuator as claimed in claim 1, wherein a configuration of the spiral spring elements is based on one or more structural parameters associated with at least one of: a spiral angle between the spiral spring elements, a helical pitch, a spiral width of the spiral spring elements, a quantity of the spiral spring elements.
5. The rotary series elastic sensing actuator as claimed in claim 2, wherein the PCB is one of a single layer PCB or a multi-layer PCB, and wherein when the PCB is the multi-layer PCB, a stiffness of the spiral spring elements is based on a number of layers and materials forming the multi-layer PCB.
6. The rotary series elastic sensing actuator as claimed in claim 1, further comprising:
one or more second sensors embedded on the substrate in a spatially-distributed manner and operable to measure temperature values across the substrate; and
one or more third sensors embedded on the substrate and operable to measure an angular displacement of the PCB,
wherein when the rotary series elastic sensing actuator is in use, the processor is further configured to receive sensor data from at least one of the one or more second or third sensors to determine the measurement of torque that is compensated for at least one of: a change in stiffness of the substrate based on the temperature values across the substrate, a rotational angle of the PCB based on the angular displacement of the PCB.
7. The rotary series elastic sensing actuator as claimed in claim 6, wherein the processor is further configured to fuse sensor data received from the at least one of: the one or more second sensors, the one or more third sensors, with the sensor data received from the one or more first sensors, by employing a sensor data fusion algorithm, to determine a measurement of torque.
8. The rotary series elastic sensing actuator as claimed in claim 1, further comprising a power delivery system embedded on the substrate, wherein the power delivery system is configured to deliver power to at least the one or more first sensors and the processor, when in use, and wherein the power delivery system comprises at least one of: a wireless means of delivering power, a wired means of delivering power.
9. The rotary series elastic sensing actuator as claimed in claim 1, further comprising a communication interface embedded on the substrate, wherein the communication interface configured to receive the measurement of torque from the processor to communicate to a central processing unit operable to control operation of the rotary series elastic sensing actuator.
10. The rotary series elastic sensing actuator as claimed in claim 1, wherein the PCB further comprises a plurality of holes for enabling coupling of the PCB with the prime mover and the load.