Industrial robot pose error dual compensation method and device

Abstract

The invention provides an industrial robot pose error dual compensation method, which comprises the following steps of: controlling each joint of an industrial robot to respectively perform independent rotary motion so as to measure arc track fixed-point motion of a tracking target, and recording to obtain a plurality of actual position points; fitting a motion plane and a motion curve of the rotary motion by using the actual position point based on the zero point; acquiring an actual point of the normal projection of the actual position point on the motion curve, and acquiring an angular position error of the joint according to the actual point and the theoretical position point of the rotary motion; obtaining a normal offset error of the joint according to the actual position point and the motion plane; and on the basis of the angle position error and the normal offset error, pose error dual compensation is carried out on the industrial robot. By measuring the angle motion error of each joint of the industrial robot, the defect of inaccurate kinematics parameter identification of a traditional industrial robot can be overcome, and the motion precision of the industrial robot can be further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial robots, and in particular relates to a method and a device for double compensation of position and posture errors of an industrial robot end. Background Art

[0002] Industrial robots have become an important means of liberating production due to their advantages of high production efficiency, high safety, and cost savings. Their reliable spatial motion accuracy is an important condition for ensuring efficient production. Due to factors such as manufacturing errors, installation errors, and encoder measurement errors of industrial robot parts, the end position accuracy is low, so it is necessary to use high-precision and efficient methods to compensate for the position error of industrial robots.

[0003] At present, the traditional kinematic parameter correction method is mostly used for the measurement and compensation of the posture error of industrial robots at home and abroad. This method is based on the kinematic model to identify and correct the kinematic parameters of the industrial robot (such as joint angle, connecting rod length, joint offset, connecting rod torsion angle, etc.) to improve the precision and accuracy of the motion of the industrial robot system, and plays a key role in the motion control and trajectory planning of the industrial robot. However, this method attributes all factors that affect the posture error of the end of the industrial robot (such as joint angle rotation motion error, deformation caused by temperature, etc.) to kinematic parameter errors, ignoring the compensation of motion errors during joint rotation, especially angular motion errors (angular position errors and tilt motion errors in two directions). The influence of this error on the posture of the end of the industrial robot under the action of the Abbe arm cannot be ignored. Summary of the invention

[0004] In view of the above problems, the present invention combines the traditional kinematic parameter correction method and proposes a dual compensation method for the terminal position and posture error of an industrial robot based on pre-compensation of the joint rotation angle motion error, including: placing the industrial robot at zero position, measuring the current position of the tracking target on the industrial robot, and recording it as the zero point; manipulating each joint of the industrial robot to perform independent rotational motion to measure the circular arc trajectory fixed-point motion of the tracking target, and recording multiple actual position points; based on the zero point, fitting the motion plane and motion curve of the rotational motion with the actual position point; obtaining the actual point of the normal projection of the actual position point on the motion curve, and obtaining the angle position error of the joint with the actual point and the theoretical position point of the rotational motion; obtaining the normal offset error of the joint with the actual position point and the motion plane; based on the angle position error and the normal offset error, compensating the rotation angle motion error of the joint. On this basis, the DH parameters of the industrial robot are identified and corrected to achieve dual compensation of the position and posture error of the industrial robot.

[0005] The dual compensation method for the posture error of an industrial robot of the present invention comprises the following steps: for any joint, the industrial robot is manipulated to move the joint at a zero point P 0 As the reference, the measurement interval is Δθ, the range of motion is -Δθ·n~Δθ·n, and the actual position point P' is measured. i (i=1,2,…,2n) spatial position coordinates; take the actual position point P' i (i=1,2,…,2n), use the least square method to fit the plane equation of the motion plane Ω1 and the spherical equation of the sphere where the motion curve is located.

[0006] The dual compensation method for the posture error of an industrial robot disclosed in the present invention obtains the spatial position coordinates of the actual position point projected on the theoretical curve based on the plane equation and the spherical equation, obtains the in-plane distance between the actual position point and the theoretical position point in combination with the spatial position coordinates of the theoretical position point on the curve, and converts the in-plane distance into an in-plane angular error; based on the in-plane angular errors of all the actual points, obtains the angular position error of each measuring point when the joint of the industrial robot rotates; based on the linear interpolation method, the data of the angular position error of each measuring point is processed to obtain the angular position error of any point of the joint of the industrial robot within the measurement range; based on the plane equation, the projection distance of the actual position point relative to the motion plane is obtained to obtain the normal offset error of each actual position point when the joint rotates; based on the linear interpolation method, the data of the normal offset error of each actual position point is processed to obtain the normal offset error of any point of the joint within the measurement range.

[0007] The present invention also proposes a dual compensation device for the posture error of an industrial robot, comprising: an initialization module, used to place the industrial robot at zero position, measure the current position of the tracking target on the industrial robot, and record it as the zero point; a measurement module, used to manipulate the joints of the industrial robot to perform independent rotational motions respectively, to measure the circular arc trajectory fixed-point motion of the tracking target, and record a plurality of actual position points; a fitting module, used to fit the motion plane and motion curve of the rotational motion with the actual position point based on the zero point; an error acquisition module, used to obtain the actual point of the normal projection of the actual position point on the motion curve, and obtain the angle position error of the joint with the actual point and the theoretical position point of the rotational motion; and obtain the normal offset error of the joint with the actual position point and the motion plane; a compensation module, used to compensate for the rotation angle motion error of the joint based on the angle position error and the normal offset error. On this basis, the DH parameters of the industrial robot are identified and corrected to achieve dual compensation of the posture error of the industrial robot.

[0008] The dual compensation device for the posture error of an industrial robot of the present invention, wherein the measurement module comprises: for any joint, manipulating the industrial robot to perform a position error with the joint at a zero point P 0 As the reference, the measurement interval is Δθ, the range of motion is -Δθ·n~Δθ·n, and the actual position point P' is measured. i (i=1,2,…,2n) spatial position coordinates; take the actual position point P' i (i=1,2,…,2n), use the least square method to fit the plane equation of the motion plane Ω1 and the spherical equation of the sphere where the motion curve is located.

[0009] The dual compensation device for the posture error of an industrial robot described in the present invention comprises an error acquisition module including an angle position error acquisition module and a normal offset error acquisition module. The angle position error acquisition module is used to acquire the spatial position coordinates of the actual position point projected on the theoretical curve based on the plane equation and the spherical equation, and acquire the in-plane distance between the actual position point and the theoretical position point in combination with the spatial position coordinates of the theoretical position point on the curve, and convert it into an in-plane angle error. Based on the in-plane angle errors of all the actual points, the angle position error of each measuring point when the joint of the industrial robot rotates is obtained, and the angle position error of any point of the joint of the industrial robot within the measurement range is obtained by data processing of the angle position error of each measuring point based on a linear interpolation method; the normal offset error acquisition module is used to acquire the projection distance of the actual position point relative to the motion plane based on the plane equation, and obtain the normal offset error of each actual position point when the joint rotates. Based on the data processing of the normal offset error of each actual position point based on a linear interpolation method, the normal offset error of any point of the joint within the measurement range is obtained.

[0010] The present invention also provides an electronic device, comprising the industrial robot posture error dual compensation device as described above.

[0011] The present invention also proposes a computer-readable storage medium storing computer-executable instructions, characterized in that when the computer-executable instructions are executed, the dual compensation method for the posture error of the industrial robot as described above is implemented.

[0012] The dual compensation method for the industrial robot's posture error proposed in the present invention can make up for the defect of inaccurate identification of the kinematic parameters of the traditional industrial robot by measuring and compensating the motion errors of each joint angle of the industrial robot in advance, and can further improve the motion accuracy of the industrial robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the laser tracker's measurement process of the industrial robot's joint rotation angle motion error.

[0014] Figure 2 It is a flow chart of the dual compensation method for the posture error of an industrial robot of the present invention.

[0015] Figure 3 It is a flow chart for obtaining the angular position error and the normal offset error.

[0016] Figure 4 It is a schematic diagram of the geometric relationship of the separation of angular motion errors during the rotational motion of the industrial robot joint 1.

[0017] Figure 5 It is the flow chart of angle motion error compensation.

[0018] Figure 6 It is a schematic diagram of the process of measuring and compensating the angular motion error during the rotational motion of the joint 1 of the industrial robot.

[0019] Figure 7 It is a schematic diagram of the process of measuring and compensating the angular motion error during the rotational motion of the industrial robot joint 2.

[0020] Figure 8 It is a schematic diagram of the process of measuring and compensating the angular motion error of the industrial robot joint during 3 rotational motion.

[0021] Fig. 9 It is a schematic diagram of the process of measuring and compensating the angular motion error of an industrial robot joint during 4 rotations.

[0022] Fig.10 It is a schematic diagram of the dual compensation device for the posture error of an industrial robot of the present invention.

[0023] Fig.11 It is a schematic diagram of the error acquisition module.

[0024] Fig.12 It is a schematic diagram of an electronic device of the present invention.

[0025] Fig.13 It is a schematic diagram of the hardware structure of an electronic device of the present invention.

[0026] Wherein, the accompanying drawings are marked as follows:

[0027] 1, 2, 3, 4, 5, 6: Joints

[0028] 7, 9, 10: Movement trajectory

[0029] 8: Tracking Target

[0030] 11: measuring laser;

[0031] 12: Laser tracker.

[0032] 13: Industrial Robots

[0033] 14: Adapter board

[0034] 100: Electronic device 20: Dual compensation device for industrial robot posture error

[0035] 21: Initialization module 22: Measurement module

[0036] 23: Fitting module 24: Error acquisition module

[0037] 241: Angle position error acquisition module 242: Normal offset error acquisition module

[0038] 25: Compensation module

[0039] S1, S2, S3, S4, S41, S42, S5, S51, S52, S6: Steps DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation method described herein is only used to explain the present invention and is not used to limit the present invention.

[0041] It should be noted that, in this application, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0042] In view of the defects of the prior art, the present invention provides a dual compensation method for the posture error of an industrial robot, which can further improve the posture accuracy of the industrial robot terminal on the basis of traditional kinematic parameter correction, and provides a reliable solution for compensating the spatial posture error of the industrial robot.

[0043] Figure 1 This is a schematic diagram of the laser tracker measuring the motion error of the industrial robot joint rotation angle. Figure 1As shown, the measuring instrument is a laser tracker 12, and the tracking target 8 of the laser tracker 12 is installed at the end of the industrial robot 13; then the joints of the industrial robot are controlled to perform single-joint rotational motion, driving the tracking target 8 to perform circular trajectory fixed-point motion; the laser tracker 12 is used to record the circular trajectory fixed-point position coordinates, and the rotation angle motion error of each joint is separated in combination with the established identification model.

[0044] Figure 2 : is a flow chart of the dual compensation method for the posture error of an industrial robot of the present invention. Figure 2 As shown, in the first embodiment of the present invention, a dual compensation method for the posture error of an industrial robot is proposed. The following takes the dual compensation for the angular motion error of joint 1 as an example to specifically illustrate the dual compensation method for the posture error of an industrial robot:

[0045] Step S1: put the industrial robot 13 at zero position, measure the current position of the tracking target 8 on the industrial robot 13 by the laser tracker 12, and record it as zero point P 0 , its spatial position coordinate is (x 0 ,y 0 ,z 0 ).

[0046] Step S2: The joint 1 of the industrial robot 13 is manipulated to perform independent rotational motion along the motion trajectory 9, and the laser tracker 12 measures and tracks the circular arc trajectory fixed-point motion of the target 8, and records and obtains a plurality of actual position points P' i (i=1,2,…,2n);

[0047] like Figure 3 As shown, the arc trajectory fixed-point motion of joint 1 is based on the zero point P 0 As a reference, the measurement interval is Δθ, and the range of motion is -Δθ·n~Δθ·n. 2n actual position points P' can be obtained. 1 , P' 2 ,……,P' i ,……,P' 2n ; Among them, P' i The spatial position coordinates of (i=1,2,…,2n) are (x' i ,y' i ,z' i );

[0048] When joint 1 moves, in the absence of motion error, the tracking target 8 at the end of the industrial robot will move along the arc trajectory 9 in the plane Ω1, and the ideal point position is (P 0 ~P 2n); When considering the angular motion error (angular position error and tilt motion error in two directions), under the action of the Abbe principle, the actual measurement point will deviate from the ideal point and become (P' 1 ~P' 2n ), which results in the end position error of the industrial robot. This error can be approximately divided into two parts: the error in plane Ω1 (caused by the angular position error) and the normal offset error of plane Ω1 (caused by the tilt motion error).

[0049] Step S3: Based on zero point P 0 , with the actual position point P' i Fitting the motion plane and motion curve of the circular trajectory fixed-point motion of joint 1; specifically including:

[0050] The actual position points should theoretically be within the spatial plane Ω1, so the least squares fitting is performed on these points to minimize the distance between all actual position points and plane Ω1, and the plane equation of plane Ω1 is obtained as follows:

[0051] a 1 x+b 1 y+c 1 z+d 1 =0

[0052] Among them, a 1 、b 1 、c 1 is the element of the plane normal vector, d 1 is the distance constant of the plane.

[0053] Because zero point P 0 (x 0 ,y 0 ,z 0 ) is used as the reference point, and there is no error in its position, so:

[0054] c 1 =(-d 1 -a 1 x 0 -b 1 y 0 ) / z 0

[0055] Combine the above formulas to solve for any spatial point P' i (x' i ,y' i ,z' i ) to the distance Δ from the plane Ω1 i :

[0056]

[0057] make

[0058] According to the least squares method The minimum, then the plane equation parameter (a 1 ,b 1 ,c 1 ,d 1 ), and the plane normal vector can also be obtained

[0059] Then, the actual position point should theoretically be on the motion trajectory 9, and the spherical equation of the space sphere where it is located is:

[0060] (xO x ) 2 +(yO y ) 2 +(zO z ) 2 =R 2

[0061] Among them (O x ,O y ,O z ) is the center of the spatial sphere, and R is the radius of the spatial sphere.

[0062] Combined with the motion trajectory 9, it must pass through the zero point P 0 (x 0 ,y 0 ,z 0 ), further construct any spatial point P' i (x' i ,y' i ,z' i )’s constraint equations:

[0063]

[0064] At the same time, the motion trajectory 9 must be on the above-mentioned fitting plane, from which we can get:

[0065] z' i =(-d 1 -a 1 x' i -b 1 y' i ) / c 1

[0066] z' i Substitute the above constraint equation and combine it with the least squares method to make The minimum value can be used to find the center of the sphere (O x ,O y ,O z ) and radius R.

[0067] Step S4, obtain the actual point of the normal projection of the actual position point on the motion curve, and obtain the angular position error of joint 1 with the actual point and the theoretical position point of the rotational motion; obtain the normal offset error of joint 1 with the actual position point and the motion plane; Figure 3 As shown, specifically including:

[0068] Step S41: Measure the angle position error of joint 1

[0069] Plane Ω 1 After the equation of the circular trajectory intersecting the spatial sphere is obtained, the angle position error will be solved. Figure 4 As shown, P 1 and P n+1 Taking the angle position error of point as an example, P 0 , P 1 , P n+1 is the theoretical position point of the industrial robot during its motion. Theoretically, this theoretical position point should be on the plane Ω 1 On the circular trajectory intersecting the space sphere, the theoretical chord lengths corresponding to the equal-interval rotation Δθ are P 0 P 1 and P 0 P n+1 However, the actual position point P' 1 and P' n+1 There is a deviation from the theoretical position point. The actual position point is projected onto the fitted circular trajectory. The projected point is Q 1 and Q n+1 , the corresponding actual chord length is P 0 Q 1 and P 0 Q n+1 According to this chord length, the actual rotation angle θ can be solved 1 and θ n+1 .

[0070] Then P n+1 Take the actual chord length corresponding to the point as an example. 1 P' n+1 , whose direction vector is Will and The cross product gives ΔO 1 P' n+1 Q n+1 The plane ω n+1 The normal vector This plane equation can be established:

[0071] a 3 (xO x )+b 3 (yO y )+c3 (zO z )=0

[0072] Joint ω n+1 The plane equation and the circle trajectory equation can be solved for the actual point Q n+1 The corresponding coordinates are:

[0073]

[0074] Similarly, point P' 1 ,P' 2 ,P' 3 ,…,P' 2n Corresponding to the actual point Q on the circular trajectory 1 ,Q 2 ,Q 3 ,…,Q 2n All can be solved. Calculate the actual rotation angle θ based on the chord length adjacent to the actual point 1 ,θ 2 ,…,θ 2n By comparing the actual rotation angle with the theoretical rotation angle, the angular position error Δθ corresponding to each position is obtained. 1 ,Δθ 2 ,…,Δθ 2n As shown in the following formula, P 1 , P n+1 The angular position error corresponding to the point can be solved.

[0075]

[0076] Step S42: measuring the normal offset error of the rotation plane of joint 1

[0077] The normal offset error can be calculated based on the actual position point to plane Ω 1 Distance calculation, such as Figure 4 Medium P' n+1 With P n+1 Deviation in Z direction Δz 1 This deviation can be measured at point P' i (x' i ,y' i ,z' i ) to plane Ω 1 The distance is expressed as:

[0078]

[0079] Step S5: Based on the angular position error and normal offset error obtained in step S4, the angle motion error of joint 1 is compensated; Figure 5 As shown, specifically including:

[0080] Step S51, performing angle position compensation on joint 1 based on the angle position error;

[0081] Step S52, performing normal offset compensation on joint 1 based on the normal offset error; comprising:

[0082] After the normal offset error is solved, it is compensated in the form of angle. Figure 6 As shown in the figure, joint 1 and joint 2 are two adjacent orthogonal rotation axes, and their distances from the tracking target are r 1 and r 2 The normal offset error of the rotation plane caused by the movement of joint 1 can be approximately transferred to joint 2 for compensation based on the Abbe principle. The compensation value is shown in the following formula:

[0083]

[0084] in, is the rotation angle of joint 1.

[0085] The plane normal offset error generated during the movement of joints 2 and 3 is expressed using the same method as above. Figure 7 and Figure 8 As shown, this normal offset error Δx 2 and Δx 3 They are approximately compensated by the rotation angle of orthogonal joint 1. The angle to be compensated is and The Abbe arm L y-p0 As the rotation of joint 1 changes, this value can be read from the industrial robot control program interface.

[0086]

[0087] is the rotation angle of joint 2 and joint 3.

[0088] For joint 4, it is relatively special. When joint 4 has no angle change and the tool coordinate origin is located at the center line of the end flange, the angle position error and plane normal offset error of joint 4 have no effect on the end error. In this case, in order to identify the rotation angle motion error of joint 4, an adapter plate 14 needs to be added to the end of the industrial robot 13. Fig. 9 As shown, the tracking target 8 of the laser tracker 12 is placed at one end of the adapter plate 14. By rotating the joint 4, the angle position error and the plane normal offset error can be measured. The plane normal offset error Δy during the rotation of the joint 4 4 The influence produced can be approximately compensated by the rotation angle of joint 5, as shown in the following formula.

[0089]

[0090] is the rotation angle of joint 4.

[0091] For the remaining joints of the industrial robot (such as joints 5 and 6), since the effective Abbe arm at the end of the industrial robot is small during movement, the influence of the angle error on the end can be ignored. Therefore, the errors of joints 5 and 6 will not be considered in the present invention.

[0092] Combined with the above joint rotation angle motion error measurement results, the linear interpolation fitting method is used to estimate and compensate the error of any angle position. Assuming that N angle positions are measured, each position Corresponding to an angle measurement error Using piecewise linear interpolation, Under the condition of , the following function model is fitted:

[0093]

[0094] in, and is the error of the corresponding angle position. For any spatial point P of the industrial robot, the angle of the corresponding theoretical joints 1 to 6 is When the angle position errors and plane normal offset errors of joints 1 to 4 are compensated, the actual angles of joints 1 to 6 are:

[0095]

[0096] Step S6: The above error compensation formula is used to compensate in the controller of the industrial robot; then the DH parameters of the industrial robot are identified using a traditional kinematic parameter identification model, and compensation correction is performed in the controller, thereby achieving double compensation of the terminal posture error of the industrial robot.

[0097] It should be noted that, in various embodiments of the present invention, the sequence numbers of the above steps do not mean the order of execution. The order of execution of the steps should be determined by their functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0098] The following is a system embodiment corresponding to the above method embodiment. This embodiment can be implemented in conjunction with the above embodiment. The relevant technical details mentioned in the above embodiment are still valid in this embodiment. In order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the above embodiment.

[0099] Fig.10 Schematic diagram of the dual compensation device for the posture error of an industrial robot according to the present invention. Fig.10As shown, in the second embodiment of the present invention, a dual compensation device 20 for posture errors of an industrial robot is proposed, which specifically includes:

[0100] An initialization module 21 is used to place the industrial robot at a zero position, measure the current position of the tracking target on the industrial robot, and record it as the zero point;

[0101] The measuring module 22 is used to manipulate the joints of the industrial robot to perform independent rotational motions respectively, so as to measure the circular arc trajectory fixed-point motion of the tracking target, and record a plurality of actual position points;

[0102] The measurement module 22 specifically includes: for any joint, manipulating the industrial robot to measure the joint with a zero point P 0 As the reference, the measurement interval is Δθ, the range of motion is -Δθ·n~Δθ·n, and the actual position point P' is measured. i (i=1,2,…,2n) spatial position coordinates; take the actual position point P' i (i=1,2,…,2n), use the least square method to fit the plane equation of the motion plane Ω1 and the spherical equation of the sphere where the motion curve is located.

[0103] A fitting module 23, for fitting the motion plane and motion curve of the rotary motion with the actual position point based on the zero point;

[0104] The error acquisition module 24 is used to obtain the actual point of the normal projection of the actual position point on the motion curve, and obtain the angle position error of the joint with the actual point and the theoretical position point of the rotary motion; and obtain the normal offset error of the joint with the actual position point and the motion plane;

[0105] The error acquisition module 24 includes an angle position error acquisition module 241 and a normal offset error acquisition module 242. Fig.11As shown; wherein, the angular position error acquisition module 241 obtains the spatial position coordinates of the actual position point projected on the theoretical curve based on the plane equation and the spherical equation, and obtains the in-plane distance between the actual position point and the theoretical position point in combination with the spatial position coordinates of the theoretical position point on the curve, and converts it into an in-plane angular error, and obtains the angular position error of each measuring point when the joint of the industrial robot rotates based on the in-plane angular errors of all the actual points, and obtains the angular position error of any point of the joint of the industrial robot within the measurement range by data processing of the angular position error of each measuring point based on the linear interpolation method; the normal offset error acquisition module 242 is used to obtain the projection distance of the actual position point relative to the motion plane based on the plane equation, obtain the normal offset error of each actual position point when the joint rotates, perform data processing on the normal offset errors of all actual position points based on the linear interpolation method, and obtain the normal offset error of any point of the joint on the motion curve.

[0106] The compensation module 25 is used to pre-compensate the angle motion error of the joint based on the angle position error and the normal offset error, and to perform DH parameter compensation on the industrial robot.

[0107] In the third embodiment of the present invention, a computer-readable storage medium is proposed. The dual compensation device for the posture error of an industrial robot of the present invention, if its function is implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a computer-readable storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. Therefore, in the third embodiment of the present invention, a computer-readable storage medium is provided for storing a computer program of a dual compensation method for the posture error of an industrial robot. It should be understood that the computer-readable storage medium in the embodiment of the present invention can be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of random access memory (RAM) are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous connection dynamic random access memory (SLDRAM) and direct rambus RAM (DRRAM).

[0108] Fig.12 Schematic diagram of an electronic device of the present invention. Fig.12As shown, in the fourth embodiment of the present invention, an electronic device 100 is proposed, including the dual compensation device for the posture error of an industrial robot as described above. A person of ordinary skill in the art can understand that all or part of the steps in the above method can be completed by instructing related hardware (such as a processor, FPGA, ASIC, etc.) through a program. All or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module in the above embodiment can be implemented in the form of hardware, such as implementing its corresponding functions through an integrated circuit, or in the form of a software function module, such as implementing its corresponding functions through a processor executing a program / instruction stored in a memory. The embodiments of the present invention are not limited to any specific form of combination of hardware and software.

[0109] It should be noted that the structure of the electronic device shown in the drawings of the present invention does not constitute a limitation thereto, and the actual knowledge structure recognition device may include more or fewer components than shown in the drawings, or a combination of certain components, or a different arrangement of components.

[0110] The electronic device of the present invention may be any device with data processing capability, and the device with data processing capability may be a device or apparatus such as a computer. The device embodiment may be implemented by software, or by hardware or a combination of software and hardware. Taking software implementation as an example, as a device in a logical sense, the processor of any device with data processing capability reads the corresponding computer program instructions in the non-volatile memory into the memory and runs the instructions. Fig.13 This is a schematic diagram of the hardware structure of an electronic device of the present invention. Fig.13 As shown, from the hardware level, it is a hardware structure diagram of any device with data processing capability where the dual compensation device for the posture error of the industrial robot of the present invention is located, except Fig.13 In addition to the processor, memory, network interface, and non-volatile memory shown, any device with data processing capabilities in which the apparatus in the embodiments is located may also include other hardware, generally based on the actual functions of the device with data processing capabilities, which will not be described in detail.

[0111] When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media sets. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium may be a solid-state hard disk.

[0112] The dual compensation method for the industrial robot's posture error proposed in the present invention can make up for the defect of inaccurate identification of the kinematic parameters of the traditional industrial robot by measuring and compensating the motion errors of each joint angle of the industrial robot in advance, and can further improve the motion accuracy of the industrial robot.

[0113] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A dual compensation method for posture error of an industrial robot, characterized in that: include: Place the industrial robot at zero position, measure the current position of the tracking target on the industrial robot, and record it as the zero point; The joints of the industrial robot are manipulated to perform independent rotational motions respectively to measure the circular arc trajectory fixed-point motion of the tracking target, and multiple actual position points are recorded; Based on the zero point, fitting the motion plane and motion curve of the rotary motion with the actual position point; Obtaining the actual point of the normal projection of the actual position point on the motion curve, and obtaining the angle position error of the joint by using the actual point and the theoretical position point of the rotary motion; Obtaining the normal offset error of the joint using the actual position point and the motion plane; Based on the angular position error and the normal offset error, the angular motion error of the joint is pre-compensated, and the DH parameter compensation is performed on the industrial robot.

2. The dual compensation method for the posture error of an industrial robot according to claim 1, characterized in that: For any joint, the industrial robot is operated to perform a rotation motion with the joint with a zero point P0 as a reference, a measurement interval of Δθ, and a motion range of -Δθ·n to Δθ·n, and 2n measurement points are obtained. The measurement point is taken as the actual position point P', and the spatial position coordinates of the actual position point are obtained; Based on the actual position point, the plane equation of the motion plane Ω1 and the spherical equation of the sphere where the motion curve is located are fitted using the least square method.

3. The dual compensation method for the posture error of an industrial robot as claimed in claim 2, characterized in that: Based on the plane equation and the spherical equation, the spatial position coordinates of the actual position point projected on the theoretical curve of the circular arc trajectory fixed-point motion are obtained; combined with the spatial position coordinates of the theoretical position point, the in-plane distance between the actual position point and the theoretical position point is obtained, and converted into a plane angle error in the motion plane; based on the plane angle errors of all the actual position points, the angular position error of each actual position point when the joint rotates is obtained; data processing is performed on all the angular position errors based on the linear interpolation method to obtain the angular position error of the joint at any point on the motion curve.

4. The dual compensation method for posture error of an industrial robot as claimed in claim 2, characterized in that: Based on the plane equation, the projection distance of the actual position point relative to the motion plane is obtained to obtain the normal offset error of each actual position point when the joint rotates. The normal offset errors of all actual position points are processed based on the linear interpolation method to obtain the normal offset error of the joint at any point on the motion curve.

5. A dual compensation device for posture error of an industrial robot, characterized in that: include: An initialization module is used to place the industrial robot at zero position, measure the current position of the tracking target on the industrial robot, and record it as the zero point; A measuring module is used to manipulate the joints of the industrial robot to perform independent rotational motions respectively, so as to measure the circular arc trajectory fixed-point motion of the tracking target and record a plurality of actual position points; A fitting module, used for fitting the motion plane and motion curve of the rotary motion with the actual position point based on the zero point; An error acquisition module is used to acquire the actual point of the normal projection of the actual position point on the motion curve, and to acquire the angle position error of the joint by using the actual point and the theoretical position point of the rotary motion; and to acquire the normal offset error of the joint by using the actual position point and the motion plane; The compensation module is used for pre-compensating the angle motion error of the joint based on the angle position error and the normal offset error, and performing DH parameter compensation on the industrial robot.

6. The dual compensation device for posture error of an industrial robot as claimed in claim 5, characterized in that: The measurement module comprises: for any joint, the industrial robot is manipulated to perform a rotation motion with the joint with a zero point P0 as a reference, a measurement interval of Δθ, and a motion range of -Δθ·n to Δθ·n, 2n measurement points are obtained by measurement, the measurement point is taken as the actual position point P', and the spatial position coordinates of the actual position point are obtained; Based on the actual position point, the plane equation of the motion plane Ω1 and the spherical equation of the sphere where the motion curve is located are fitted using the least square method.

7. The dual compensation device for posture error of an industrial robot as claimed in claim 6, characterized in that: The error acquisition module includes an angle position error acquisition module, which is used to obtain the spatial position coordinates of the actual position point projected on the theoretical curve of the circular arc trajectory fixed-point motion based on the plane equation and the spherical equation; in combination with the spatial position coordinates of the theoretical position point, obtain the plane distance between the actual position point and the theoretical position point, and convert it into a plane angle error in the motion plane; based on the plane angle errors of all the actual position points, obtain the angle position error of each actual position point when the joint rotates; perform data processing on all the angle position errors based on the linear interpolation method to obtain the angle position error of any point of the joint on the motion curve.

8. The dual compensation device for posture error of an industrial robot as claimed in claim 6, characterized in that: The error acquisition module includes a normal offset error acquisition module, which is used to obtain the projection distance of the actual position point relative to the motion plane based on the plane equation, obtain the normal offset error of each actual position point when the joint rotates, perform data processing on the normal offset errors of all actual position points based on the linear interpolation method, and obtain the normal offset error of the joint at any point on the motion curve.

9. An electronic device comprising the dual compensation device for posture errors of an industrial robot as claimed in any one of claims 5 to 8.

10. A computer-readable storage medium storing computer-executable instructions, characterized in that: When the computer executable instructions are executed, the dual compensation method for posture errors of an industrial robot as claimed in any one of claims 1 to 4 is implemented.

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