DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
and
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. TITLE OF THE INVENTION
SYSTEM AND METHOD FOR ROBOTIC PATH CORRECTION
2. APPLICANTS
(a) Name : GRIFFYN ROBOTECH PVT. LTD.
(b) Nationality : The Indian Company
(c) Address : Shewale Centre, MIDC, Pimpri Colony, Pimpri-Chinchwad, Maharashtra 411019, India

3.PREAMBLE TO THE DESCRIPTION
PROVISIONAL
The following specification describes the invention COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

SYSTEM AND METHOD FOR ROBOTIC PATH CORRECTION
FIELD OF THE INVENTION
The present invention generally relates to robotics and particularly to a system and method for correcting robotic path when a robotic arm is used to automate building of a product.
BACKGROUND OF THE INVENTION
A typical manufacturing part/component comes with inherent inaccuracies. There are multiple factors that contribute to the anomalies viz.:
1. Variations in size, shape, and geometry of child parts due to previous manufacturing steps, such as the metal forming, forging, sand casting.
2. Variation in the positioning of parts in the assembly fixture or jig
3. Variation due to the joining process such as welding, bolting etc.
When a robotic arm is used to automate building of a product that goes through any one or all the processes mentioned, it is handicapped by its limitation to achieve the same pose throughout every cycle. Considering an application wherein, a robot is supposed to dispense a viscous liquid or a weld two components, if the robot interpolates to achieve the same pure encoder-based pose on which it’s teaching is based on, there are chances that the robot’s end-effector collides with the job.
A prior art technique available today includes a seam tracking systems incorporated with robotic arm for said corrections. A laser profiler sensor is mounted on the robot’s end of arm tooling (EOAT) and programmed in such a way that it leads the dispensing/welding tool on the path of interest thus sending real-time offsets to the robot for correcting the path traced. Normally, such techniques work well for straight rungs, however, they fail to give accurate result when the orientation of the tool needs to change, in case of circular or spherical rungs for instance. These tool re-orientation changes have no effect on the proposed system. Hence the system does not work well for circular/ spherical rungs. Moreover, the system spoils the job when the dispenser or weld is interrupted due to noise it receives from the sensor, considering there are interrupts to handle it.
Another prior art technique of similar purpose is configured with image capturing devices such as camera and laser distance sensors-based system for BIW dispensing or welding application. Here the BIW is scanned using the camera system and the corresponding tactical distances are measured using multiple laser sensors. This helps in correcting all the dispensing or welding rungs in the application. However, this means that there must be certain datum on which the whole body will be corrected. Further, it may not account for geometric variations of child parts or their previous machining processes. Hence a well-designed intelligence through sensor perception in correcting the robot’s trajectory becomes quite vital in proving a successful automation.
Accordingly, there exists a need to provide a system and method for correcting the robot’s trajectory that would eliminate the deficiencies of the conventional techniques.
OBJECTS OF THE INVENTION
An object of the present invention is to control the position of the robotic arm and correct the robotic path depending upon the actual position of the rung.
Another object of the present invention is to provide a pre-process scan over specific strategic points on the rung and send the data to Robots Controller to store master readings.
Still another object of the present invention is to eliminate the need of sensor beam alignment with the work piece, in robotic path correction.
Yet another object of the present invention is to provide a system and method for robotic path correction that will automatically account for both geometric and process variations of the child parts.
Yet another object of the present invention is to provide a system and method for robotic path correction, with minimal effect on cycle time, reduced consumables and increased efficiency.
Yet another object of the present invention is to provide a system and method for path correction for a plurality of robots are present in a same working space at a plant, and the individual robots are not specifically defined for any movements.
Yet another object of the present invention is to provide a system and method for robotic path correction, when several work objects are to be processed or handled by a robot.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
Figure 1 shows a system for correcting robotic path, in accordance with an embodiment of the present invention;
Figure 2A illustrates a base coordinate system linked to a mounting base and a stationary base of a robot in accordance with an embodiment of the present invention;
Figure 2B illustrates a world coordinate system concurrent with the base coordinate system of a robot in accordance with an embodiment of the present invention;
Figure 2C illustrates a user coordinate system related to essential points of the technological process of robotic automation when the robot is configured such that it can work with different fixtures or work pieces having different positions and orientations in accordance with an embodiment of the present invention;
Figure 2D illustrates an objects coordinate system that is targeted to an object on which a robot can work with different fixtures or working surfaces having different positions and orientations;
Figure 3A, 3B, 3C and 3D illustrate method for correcting robotic path, in accordance with an embodiment of the present invention; and
Figure 4 illustrates a method for correcting robotic path, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques, and approaches are overcome by the present invention as described below in the preferred embodiments.
The present invention described provides a system and method for correcting the path of a robot. This is achieved by incorporating a sensor module equipped with a 2D laser profiler that scans specific strategic points on a rung. The data collected by the sensor module serves as input for correcting the robot's path. The purpose of this correction is to accurately determine the actual position of the rung. By knowing the precise location of the rung, the robot can make adjustments to its path. This is particularly useful when the robot is tasked with automating functions such as dispensing materials or welding two metal parts together. Thus the invention involves using a sensor module with a 2D laser profiler to scan key points on a rung, allowing the robot to correct its path based on the actual position of the rung. This ensures more precise and reliable automation of various tasks such as dispensing and welding.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in brackets in the following description.
In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
Throughout this application, with respect to all reasonable derivatives of such terms, and unless otherwise specified (and/or unless the particular context clearly dictates otherwise), each usage of:
“a” or “an” is meant to read as “at least one.”
“the” is meant to be read as “the at least one.”
References in the present invention to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one of the embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
Embodiments of the present invention include various steps, which will be described below. The steps may be performed by hardware components and may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special purpose processor programmed with the instructions to perform the steps. Alternatively, steps may be performed by a combination of hardware, software, firmware and a combination thereof.
Various methods described herein may be practiced by combining one or more machine-readable storage media containing the code according to the present invention with appropriate standard processing modules to execute the code contained therein. A system and a method for practicing various embodiments of the present invention may involve one or more processors and storage systems containing to computer program(s) coded in accordance with various methods described herein, and the method steps of the invention could be accomplished by modules, routines, subroutines, or subparts of a computer program product.
If the specification states a component or feature "may' can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
As used in the description herein and throughout the claims that follow, the meaning of "a, an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this invention will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
Parts of the description may be presented in terms of operations performed by at least one electrical / electronic circuit, a processing unit, using terms such as data, state, link, fault, packet, and the like, consistent with the manner commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. As is well understood by those skilled in the art, these quantities take the form of data stored/transferred in the form of no transitory, computer-readable electrical, magnetic, or optical signals capable of being stored, transferred, combined, and otherwise manipulated through mechanical and electrical components of the computer system; and the term computer system includes general purpose as well as special purpose data processing machines, switches, and the like, that are standalone, adjunct or embedded. For instance, some embodiments may be implemented by a processing unit that executes program instructions so as to cause the processing unit to perform operations involved in one or more of the methods described herein.
The program instructions may be computer-readable code, such as compiled or non-compiled program logic and/or machine code, stored in a data storage unit that takes the form of a non-transitory computer-readable medium, such as a magnetic, optical, and/or flash data storage unit.
While embodiments of the present invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the scope of the invention, as described in the claim.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.
In an aspect of the present invention, a system for correcting robotic path is disclosed, the system comprises a robot, a controller, and a communication module, wherein the robot communicates with a controller through a communication module. The controller is equipped with a storage module, a calculator module, and a comparator module. Additionally, the robot includes a sensor module for scanning strategic points on the rung, and the collected data is transmitted to the controller for further processing using the storage, calculator, and comparator modules. The controller is adapted to calculate and store master readings from the scanner module, compares realtime observed readings with the master readings, generates offsets based on the differences, and utilizes these offsets to correct the robot's path according to the desired trajectory.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in brackets in the following description.
Referring to figures 1 a system (100) for correcting robotic path (hereinafter referred as “the system (100)” in accordance with an embodiment of the preset invention is shown. The system (100) consists of a robot (20) and a controller (70) in communication with the robot (20) through a communication module (90).
The robot (20) in the system is equipped with multiple manipulator joints to facilitate movements and a sensor module (60) that is mounted at specific strategic points on the rung. In the disclosure, term "rung" may be referring to a particular point or position on the path or trajectory traced by the robot that is being corrected. The purpose of the sensor module (60) is to collect data related to the robot's surroundings and transmit the observed data to the controller (70) through a communication interface (80). The communication interface (80) is provided to ensure effective communication and data transmission, between the robot (20) and the controller (70).
In an embodiment, the sensor module (60) incorporates a laser profiler and a sensor pair for scanning the robot's surroundings. The laser profiler is responsible for generating a detailed profile of the environment, while the scanner detects the edges of the workspace (40). By detecting these edges, the robot (20) can accurately determine the boundaries and constraints of its working area.
The sensor module (60) is configured to perceive the actual position of the rung that corrects the robot trajectory to provide a successful automation of a work using the robot (20). In the embodiment, the sensor module (60) facilitates a pre-process scan at specific points, using the 2D laser profiler that in turn help the robot (20) to correct its path on which it is supposed to work on an object or a job such as dispensing of fluid or welding of two metal parts and like. The sensor module (60) transmits the observed readings to the controller (70) for further processing that instructs a driver for correcting the robot path in accordance with the processed data.
The controller (70) is equipped with at least one processing unit, which works in conjunction with a driver containing electromechanical units necessary for interfacing with the robot (20). The processing unit comprises at least one processor that communicates with a machine-readable storage medium and is configured to execute an application module stored within the storage medium. This application module contains a set of instructions that guide the controller operations. Within the processing unit, the storage medium includes various modules such as a calculator module and a comparator module, among others. These modules are designed to perform specific functions related to data processing and analysis. The calculator module handles calculations required for various tasks, while the comparator module compares different values for decision-making purposes.
The controller (70) is configured for performing several functions. Firstly, the controller receives the sensor module (60) output data and calculates and stores the first observed reading as a master readings for a particular work piece (40). These master readings serve as reference points for comparison. Next, the controller (70) compares the realtime observed readings obtained from the scanner module with the stored master readings. By analyzing the differences between the realtime observed reading and the master readings, the controller (70) generates offsets. These offsets represent the necessary adjustments that need to be made to correct the path traced by the robot (20). These generated offsets are specifically used to guide the robot (20) towards the required path. By applying the calculated corrections based on the offsets, the robot (20) can navigate accurately and perform the intended tasks.
Referring to the figure 2A to 2D, a plurality of co-ordinate systems used for the realization of control functions of the robot (20) is shown in accordance with an embodiment of the present invention. In an implementation of an embodiment, the controller (70) is configured for controlling the path and movements of the robot (20) manipulator joints or gripper by means of the driver. The motion of manipulator joints of the robot (20), the tool or the gripper in a preferred embodiment is described with respect to a plurality of coordinate systems. The path traced by the robot is based on coordinates of a plurality of coordinate systems (110, 120, 130 and 140) and is used for the realization of several control functions thereof. Different coordinates of the coordinate system (110, 120, 130 and 140) are used for the realization of several control functions.
Referring to figures 2A, a base coordinate system (110) linked to the mounting base and stationary base of the robot (20) is portrayed. The processing unit is configured for modelling a function based on the base coordinate system (110) of a point on the rung where the z-axis coincide with axis 1 of the robot (20).
Further, referring to the figure 2B, the processing unit is configured for modelling a function based on a world coordinate system (120) concurrent with the base coordinate system (110) of the robot (20). The world coordinate system (120) is configured for normal conditions such as if the robot (20) is not specifically defined for any movements and a plurality of robots (20) are present in a same working space at a plant, a common world coordinate system (120) is adopted to enable individual modules for a specific robot (20) in the programming unit to communicate with one another and therefore the robots (20).
Further, referring to the figure 2C, the processing unit is configured for modelling a function based on a user coordinate system (130) related to the essential points of the technological process of the robotic automation. The robot (20) is configured such that it can work with different fixtures or work pieces having different positions and orientations. The user coordinate system (130) is used to get different coordinate systems for different fixtures/ work pieces (40). A fixture, however, may include several work objects (42) that are to be processed or handled by the robot (20). If all the positions are stored in the object coordinates, reprogram is not needed if a fixture must be moved or turned. By moving (translating or turning) the user coordinate system (130) as much as the fixture/ work piece (40) has been translated or turned, all programmed positions will follow the fixture/ work piece (40) and no reprogramming will be required.
Furthermore, processing unit is configured for modelling a function on an objects coordinate system (140) targeted to an object (42) as shown in figure 2D. As discussed, a robot (20) can work with different fixtures or working surfaces having different positions and orientations and the user coordinate system (130) is different coordinate systems for different fixtures or working surfaces. A fixture/work piece (40), however, may include several work objects (42) that are to be processed or handled by the robot (20). Thus, it often helps to define a coordinate system for each object (42) to make it easier to adjust the program if the object is moved or if a new object, the same as the previous one, is to be programmed at a different location.
In the embodiment, a fixture/work piece (40) refers to a device or mechanism used to securely hold and position a work piece or an object during the robotic operation. A fixture/work piece (40) is essential in automation processes to ensure stability and accuracy during tasks such as assembly, machining, welding, or inspection.
The user coordinate system (110) or object co-ordinate system (140) finds its application in the present invention when the robot (20) needs all the regions for the applications such as liquid dispense or welding. In such situations, the regions are defined as teach points in one of these co-ordinate systems.
In an another aspect of the present invention, referring to figure 3A to 3C, a method for correcting robotic path (150), is shown in accordance with the present invention. The method of operation (150) is a three step process as follows,
In the first step, referring to figure 3A, the sensor module (60) mounted along the robot arm and is configured to scan the surroundings of the robot (20). This allows a pre-scan over specific strategical points on the rung and send the data to the controller (70). The scanning process helps to detect the edges from the images of the work piece or fixture/work piece (40) captured. The controller (70) further calculates the exact co-ordinates of the point in the fixture/work piece (40) where it detected an edge in the region of interest. The sensor module (60) communicates two values corresponding to the edge point along the laser line denoted by X, and the distance of the edge point from the profiler face denoted by Z.
Referring to the figure 3B, in the second step, the co-ordinate system is applied/defined on the desired rung such that one of the co-ordinate axis of the object co-ordinate system (140) aligns with the rung. Here, Z axis is aligned normal to the XY plane of the object coordinate system.
Further, referring to figure 3C, the number of scans are decided on specific distances to get the appropriate corrections, depending on the expected variations. Here,
• the sensor module (60) scans for a distance of 1-Y to correct the object frame in Y and/or Z direction;
• the sensor module (60) scans for a distance of 2-X to correct the object frame in X and/or Z direction; and
• the sensor module (60) scans for a distance of 3-X to correct the object frame in rotation about Z axis (Yaw) and rotation about Y axis (Pitch) with respect to the rung.
The sensor module (60) scans along the object frame as described and communicates a first reading to the controller (70) and is stored as the master reading.
In the third step, the sensor module (60) continues to scans on the job and send the observed readings to the controller (70). The controller (70) then compares the realtime observed readings with the master readings and generate offsets that helps to correct to the required path traced by the robot (20). The master reading considered for the same job on the same work space (40) is taken as reference value on which the robot’s (20) physical teaching relies on. When, the robot (20) runs a routine to calculate the offsets by comparing realtime observed readings with the master readings thus forming a corrected object frame about which the robot (20) can function. The controller (70) accordingly provide control instructions for the driver to adjust the movements of the manipulators that works on an object (42) mounted on fixtures/ work pieces (40) and allow the manipulators to work on the objects (42) held by the fixture (40). The functionality of robot (20) includes but not limited to dispense the fluid, weld two metal components etc.
ADVANTAGES OF THE INVENTION
1. During robotic automation, the method leaves no effect of changes in robotic tool orientation along the path.
2. The system (100) eliminates the need of sensor beam alignment with the work piece, thus no effect of sensor inclination while scanning the part.
3. The system (100) automatically accounts for both geometric and process variations of the child parts.
4. By employing reduced number of consumables particularly up-to 40%, the system (100) performs increased efficiency in correcting the robotic path.
5. The system (100) functions with minimal effect on cycle-time.
6. The method (150) offers a powerful and modular programming software and integration.
7. The system (100) offers a rugged design in accordance with industrial standards.
8. Successfully proven the system with Yaskawa robotic arm and can be integrated with any other standard robots.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.
,CLAIMS:We claims:
1. A system (100) for correcting robotic path, having a robot (20) configured to cooperate with a plurality of manipulators that works on object (42) mounted on fixtures/ work pieces (40) having different positions and orientations, the system (100) comprising,
a sensor module (60) mounted at specific point on a position on trajectory followed by the robot (20), wherein the sensor module (60) is configured to scan along an object frame to detect exact co-ordinates of a point in the fixture/work piece (40) with respect to the actual position of the rung;
a controller (70) in communication with the robot (20) via a driver and the sensor module (70), the controller (70) includes a processing unit having at least one processor that communicates with a machine-readable storage medium and configured to execute an application module stored within the storage medium that guides the controller operations;
a communication module (90), the communication module (90) configured to communicatively couple the controller (70) with the sensor module (60) and with the robot (20);
wherein the controller (70) is configured to receive the observed readings from the sensor module (60), calculates the first value corresponding to an object frame as a master reading for a particular work piece (40), storing the master reading as a reference for comparison, generating offset values by comparing the master reading with a realtime reading from the sensor module (60), sending instructions to the driver for correcting the robot trajectory based on a plurality of coordinate systems (110,120,130,140) defined for robot base, fixtures/ work piece (40) and the objects (42) to provide a successful automation of work by means of the robot (20).
2. The system as claimed in claim 1, wherein the sensor module (60) comprises a laser profiler and a sensor pair configured to scan the surroundings of the robot (20) for detecting the edges of the fixture/work piece (40) from the observed readings.
3. The system (100) as claimed in claim 1, wherein the plurality of coordinate systems defined for robot base and the fixtures/ work piece include base coordinate system (110), world coordinate system (120), user coordinate system (130), and objects coordinate system (140).
4. The system (100) as claimed in claim 3, wherein the base coordinate system (110) is linked to the mounting base and stationary base of a robot (20) that the processing unit is configured for modelling a function based on the base coordinate system (110) of a point on the rung where the z-axis coincide with axis 1 of the robot (20).
5. The system (100) as claimed in claim 3, wherein the world coordinate system (120) is linked to a plurality of robots (20) work within the same working space upon no base coordinate system is defined for individual robots (20) that the processing unit is configured for modelling a function for the plurality of robots (20) based on the world coordinate system (120) to enable individual modules corresponding to one robot (20) communicate with one another.
6. The system (100) as claimed in claim 3, wherein the user coordinate system (130) is defined for a fixture/work piece (40) of robots (20) that the processing unit is configured for modelling a function based on the user coordinate systems (130) for a plurality of fixtures/work pieces (40) associated with a same robot (20) that each of a plurality of fixtures/ work pieces (40) may get different coordinate systems without remodeling of the coordinate system created in the processing unit.
7. The system (100) as claimed in claim 3, wherein the object coordinate system (140) is linked to each of the plurality of objects (42) supported by a fixture/work piece (40), that the processing unit is configured for modelling a function based on the object coordinate system (140) for each of the plurality of objects (42) processed or handled by the robot (20) such that the object positions are stored in the object coordinates, and no reprogram is needed in case of the object (42) is moved/turned.
8. A method (150) for correcting robotic path (150), having a robot (20) configured to cooperate with a plurality of manipulators that works on objects (42) mounted on fixtures/ work pieces (40) having different positions and orientations, the method (150) comprising steps of:
scanning, by the sensor module (60), specific strategical points on the rung and send the observed readings to the controller (70) for processing and detecting the edges of the fixture/work piece (40);
calculating, by the controller (70), the exact co-ordinates of the point in the work piece (40) where an edge in the region of interest is detected;
applying, by the controller (70), co-ordinate system on the rung in such a way that one of the co-ordinate axis of the object co-ordinate system (140) aligns with the rung;
deciding, by the controller (70), number of scans done by the sensor module (60) on specific distances to correct the position of the rung and directing sensor module (60) to scan along the object frame;
storing, by the controller (70), a observed readings from the first sensor module (60) as a master reading and calculating offsets by comparing realtime readings with the master reading; and
correcting, by the controller (70), the object frame and sending instructions to the robot (20) via driver to adjust the movements and position the robot (20) based on a plurality of coordinate systems (110,120,130,140) defined for robot base, fixture/work piece (40) and object (42) for successful automation of work.
9. The method (150) as claimed in claim 8, wherein the controller (70) applies co-ordinate system on the desired rung to align the co-ordinate axis of the object co-ordinate system (140) with the rung such that the Z axis is aligned normal to the XY plane of the object coordinate system.
10. The method (150) as claimed in claim 8, wherein the scanning of sensor module (60) on specific distances to correct the position of the rung includes the steps of:
scanning, by the sensor module (60), for a distance of 1-Y to correct the object frame in Y and/or Z direction;
scanning, by the sensor module (60), for a distance of 2-X to correct the object frame in X and/or Z direction; and
scanning, by the sensor module (60), for a distance of 3-X to correct the object frame in rotation about Z axis (Yaw) and rotation about Y axis (Pitch) with respect to the rung.
Dated this on 20th day of May, 2023

Ragitha. K
(Agent for Applicant)
IN-PA/2832