Method and system for calibrating torque sensor of robot joint

Abstract

The present invention provides a method and system for calibrating a torque sensor of a robot joint, the method comprising the following steps: controlling a target arm corresponding to a target joint to move at a constant speed along a preset direction, and recording the position of the target arm and the measured value of the torque sensor corresponding to the target joint after each movement cycle; extracting a first position data set of the target arm corresponding to the maximum or minimum measured value, and obtaining the target position of the target arm according to the first position data set; controlling the target arm to move to a second position where the force arm is equal to zero according to the target position; and obtaining the bias of the torque sensor according to the second position. Thus, the calibration of the torque sensor can be achieved by controlling the robot's mechanical arm to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and the complexity of the operation, and improving the calibration efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of sensor calibration, and in particular to a torque sensor calibration method for a robot joint and a torque sensor calibration system for a robot joint. Background Art

[0002] In the related art, when calibrating the torque sensor, an additional load needs to be added for calibration, which not only complicates the operation, but also greatly increases the calibration time and reduces the calibration efficiency. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for calibrating a torque sensor of a robot joint. The torque sensor can be calibrated by controlling the robot's mechanical arm to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and operation complexity and improving the calibration efficiency.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A method for calibrating a torque sensor of a robot joint, characterized in that it includes the following steps: controlling a target arm corresponding to the target joint to move at a constant speed along a preset direction, and recording the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each movement cycle; extracting a first position data set of the target arm corresponding to when the measurement value is maximum or minimum, and obtaining a target position of the target arm based on the first position data set; controlling the target arm to move to a second position where the force arm is equal to zero based on the target position; and obtaining the bias of the torque sensor based on the second position.

[0006] Before controlling the target arm corresponding to the target joint to move at a uniform speed along the preset direction, the method further includes: adjusting the posture of the target joint to a target posture so that the axis of the target joint is perpendicular to the gravity direction of the target arm.

[0007] Before controlling the target arm corresponding to the target joint to move at a uniform speed along the preset direction, the method further includes: mounting the robot on a horizontal base for calibration of the joints connecting the robot and the base.

[0008] Acquiring the target position of the target arm according to the first position data set includes: calculating an average value of each first position data in the first position data set to acquire the target position of the target arm.

[0009] Controlling the target arm to move to a second position where the force arm is equal to zero according to the target position includes: controlling the target arm to rotate 90° counterclockwise or clockwise at the target position to move the target arm to the second position where the force arm is equal to zero.

[0010] The torque sensor calibration method for a robot joint also includes: calculating the first-order gravity moment of the target joint according to the bias of the torque sensor, and performing gravity compensation on the target joint according to the first-order gravity moment.

[0011] Before controlling the target arm corresponding to the target joint to move at a uniform speed along the preset direction, the method further includes: performing zero position calibration on each joint of the robot.

[0012] The speed of the uniform motion is within a range of 5 degrees / s to 10 degrees / s.

[0013] A torque sensor calibration system for a robot joint, characterized by: a first control module, wherein the first control module is used to control a target arm corresponding to the target joint to move at a constant speed along a preset direction, and to record the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each movement cycle; a first acquisition module, wherein the first acquisition module is used to extract a first position data set of the target arm corresponding to when the measurement value is maximum or minimum, and to acquire a target position of the target arm based on the first position data set; a second control module, wherein the second control module is used to control the target arm to move to a second position where the force arm is equal to zero based on the target position; and a second acquisition module, wherein the second acquisition module is used to acquire the bias of the torque sensor based on the second position.

[0014] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the torque sensor calibration method of the robot joint is implemented.

[0015] Beneficial effects of the present invention:

[0016] The present invention can realize the calibration of the torque sensor by controlling the mechanical arm of the robot to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and the complexity of the operation and improving the calibration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a method for calibrating a torque sensor of a robot joint according to an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of adjusting the posture of a target joint of a collaborative robot according to a specific embodiment of the present invention;

[0019] Figure 3 Schematic diagram of a torque sensor calibration system for a robot joint according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Figure 1 is a flow chart of a method for calibrating a torque sensor of a robot joint according to an embodiment of the present invention.

[0022] like Figure 1 As shown, the torque sensor calibration method of the robot joint according to the embodiment of the present invention may include the following steps:

[0023] S1, controlling the target arm corresponding to the target joint to move at a constant speed along a preset direction, and recording the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each movement cycle.

[0024] It should be noted that before controlling the target arm corresponding to the target joint to move at a constant speed along the preset direction, the posture of the target joint of the robot can be adjusted so that the axis of the target joint is perpendicular to the gravity direction of the target arm, so that the target arm becomes the load of the target joint.

[0025] Take collaborative robots as an example. Figure 2 As shown, in one embodiment of the present invention, the target joint may be an elbow joint, and its zero position is defined as the vertical upward position of the robot arm, that is, Figure 2 In this state, the forearm with unknown parameters is the load of the elbow joint. When the forearm moves to different positions, different torques will be generated at the elbow joint. The torque sensor of the elbow joint can measure this torque value.

[0026] In another embodiment of the present invention, Figure 2 As shown, the target joint can be the first joint, and its zero position is defined as the position where both the robot arm and the forearm are kept vertically upward, that is, Figure 2 In this state, the upper arm and all joints above the upper arm and the forearm with unknown parameters are the load of the first joint. When the upper arm moves to different positions, different values ​​of torque will be generated at the first joint. The torque sensor of the first joint can measure this torque value.

[0027] It should be noted that the robot in the present invention may include but is not limited to a six-axis robot, and may also be other robots, for example, an eight-axis robot.

[0028] Among them, for the joints connecting the robot and the base, the joint axes cannot be adjusted to be perpendicular to the direction of gravity by changing the robot's posture. Therefore, the robot can be installed on a horizontal base for calibration.

[0029] Furthermore, before controlling the target arm corresponding to the target joint to move at a constant speed along the preset direction, each joint of the robot can be zero-calibrated, and specifically, each joint of the robot can be zero-calibrated by conventional means (e.g., customized tooling, laser tracker, etc.), and after calibration, the difference between the command position and the actual position of each joint of the robot is within the error tolerance range. Therefore, before calibrating the torque sensor of the robot joint, each joint of the robot can be zero-calibrated to ensure the subsequent accurate control of the target arm corresponding to the target joint, thereby ensuring the accuracy of the calibration.

[0030] Furthermore, when controlling the target arm corresponding to the target joint to move at a constant speed along a preset direction (for example, counterclockwise), the movement speed can be within 5 degrees / s to 10 degrees / s. Taking a two-stage robotic arm as an example, the joint connected to the first-stage robotic arm and the second-stage robotic arm is the target joint, and the second-stage robotic arm can be controlled to rotate at a constant speed counterclockwise with the target joint as the center. At this time, the position of the target arm and the measured value of the torque sensor corresponding to the target joint can be recorded every time a motion cycle (the motion cycle can be within 30 to 50 ms). More recorded data is obtained in a short period to ensure the accuracy of subsequent position calculations. Thus, the position information of the target arm can be accurately recorded.

[0031] S2, extracting a first position data set of the target arm corresponding to when the measured value is maximum or minimum, and acquiring the target position of the target arm according to the first position data set.

[0032] Specifically, after recording the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each motion cycle, the first position data set of the target arm corresponding to the maximum or minimum measurement value can be extracted from the recorded data, and the target position of the target arm can be obtained based on the first position data set.

[0033] Specifically, when the gravity is directed downward, the gravity generated by the target arm is a vector passing through the center of mass of the forearm and pointing vertically downward. During the movement of the forearm, the center of mass of the forearm moves in a circular motion. The horizontal distance between the center of mass of the forearm and the axis of the target joint, i.e., the force arm, changes with the position and can be expressed by the following formula:

[0034] T r =mg*l(q), (1)

[0035] Among them, T r is the true torque value, m is the load mass, and l(q) is the lever arm. When the distance between the center of mass of the forearm and the axis of the target joint is the farthest, that is, when the lever arm l(q) is the largest, the torque generated at the target joint is the largest, that is, T r The absolute value of is the largest. Among them, the actual torque value and the measured value of the torque sensor satisfy the following formula:

[0036] T-T0=T r , (2)

[0037] Wherein, T is the measured value of the torque sensor, and T0 is the offset of the torque sensor.

[0038] According to formula (2), T r The absolute value of T is the largest and r >0, T takes the maximum value, T r The absolute value of T is the largest and r When <0, T takes the minimum value. At the same time, since the position of the target arm and the measured value of the torque sensor are recorded simultaneously, when T takes the maximum or minimum value, the corresponding first position data set of the target arm can be directly extracted. For example, the first position data set of the target arm corresponding to when T takes the maximum value can be extracted, wherein the first position data set can be composed of a plurality of first position data, and the first position data can be the angle (between 0° and 360°) of rotation of the target arm from the initial position to the position of the target arm corresponding to when T takes the maximum value, or the angle (between 0° and 360°) of rotation of the target arm from the initial position to the position of the target arm corresponding to when T takes the minimum value.

[0039] Furthermore, the first data set is processed to calculate the accurate target arm position. The target position of the target arm can be obtained by, but not limited to, calculating the average value of each first position data in the first position data set. A single data value has a large error and cannot guarantee the accuracy of the data. The average value of multiple sets of data is taken to reduce the error, thereby accurately obtaining the position of the target arm.

[0040] S3, controlling the target arm to move to a second position where the lever arm is equal to zero according to the target position.

[0041] S4, obtaining an offset of the torque sensor according to the second position.

[0042] Specifically, when the target arm is at the target position, the target arm can be controlled to rotate 90° counterclockwise or clockwise at the target position so that the target arm moves to the second position where the force arm is equal to zero. At this time, according to formula (1), since the force arm l(q) is equal to 0, the true torque value T r= 0, then, combined with formula (2), we know that T = T0. That is, after the target arm is controlled to rotate 90° counterclockwise or clockwise at the target position, the measured value of the torque sensor corresponding to the second position of the target arm is the offset of the torque sensor.

[0043] In one embodiment of the present invention, after obtaining the bias of the torque sensor, when the forearm of the robot is controlled to move to the third position, the first-order gravity torque of the corresponding load can be calculated according to the bias of the torque sensor by the following formula:

[0044] mgl(q i )=T-T0 (3)

[0045] Among them, l(qi) is the force arm corresponding to the robot's forearm in the third position.

[0046] Therefore, the present invention can calibrate the torque sensor by controlling the robot's mechanical arm to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and operation complexity and improving the calibration efficiency.

[0047] In summary, according to the torque sensor calibration method of the robot joint of the embodiment of the present invention, the target arm corresponding to the target joint is controlled to move at a constant speed along the preset direction, and the position of the target arm and the measured value of the torque sensor corresponding to the target joint are recorded after each movement cycle, and the first position data set of the target arm corresponding to the maximum or minimum measured value is extracted, and the target position of the target arm is obtained according to the first position data set, and the target arm is controlled to move to the second position where the force arm is equal to zero according to the target position, and the bias of the torque sensor is obtained according to the second position. Therefore, the calibration of the torque sensor can be achieved by controlling the robot's mechanical arm to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and the complexity of the operation, and improving the calibration efficiency.

[0048] Corresponding to the robot joint torque sensor calibration method of the above embodiment, the present invention also proposes a robot joint torque sensor calibration system.

[0049] like Figure 3 As shown, the torque sensor calibration system for a robot joint according to an embodiment of the present invention may include: a first control module 100 , a first acquisition module 200 , a second control module 300 and a second acquisition module 400 .

[0050] Among them, the first control module 100 is used to control the target arm corresponding to the target joint to move at a constant speed along a preset direction, and record the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each movement cycle; the first acquisition module 200 is used to extract the first position data set of the target arm corresponding to the maximum or minimum measurement value, and obtain the target position of the target arm according to the first position data set; the second control module 300 is used to control the target arm to move to a second position where the force arm is equal to zero according to the target position; the second acquisition module 400 is used to obtain the bias of the torque sensor according to the second position.

[0051] According to one embodiment of the present invention, before controlling the target arm corresponding to the target joint to move at a uniform speed along the preset direction, the first control module 100 is also used to: perform zero-position calibration on each joint of the robot; and adjust the posture of the target joint of the robot so that the axis of the target joint is perpendicular to the direction of gravity.

[0052] It should be noted that before controlling the target arm corresponding to the target joint to move at a constant speed along the preset direction, the joints of the robot can be zero-calibrated and / or the posture of the target joint of the robot can be adjusted so that the axis of the target joint is perpendicular to the direction of gravity. Specifically, conventional means (for example, customized tooling, laser tracker, etc.) can be used to zero-calibrate the joints of the robot. After the calibration, the difference between the command position and the actual position of each joint of the robot is within the allowable error range. At the same time, the joint posture can be adjusted so that the axis of the joint to be tested (target joint) is perpendicular to the direction of gravity. For the joints connected to the base, the joint axis cannot be adjusted to be perpendicular to the direction of gravity by changing the robot posture. The robot can be mounted on a horizontal base for calibration.

[0053] Further, after zero-calibrating each joint of the robot and adjusting the posture of the target joint of the robot so that the axis of the target joint is perpendicular to the direction of gravity, the target arm corresponding to the target joint is controlled to move uniformly along a preset direction (for example, counterclockwise) (the speed of uniform motion can be within 5 degrees / s to 10 degrees / s). Taking a two-stage robotic arm as an example, the joint connected to the first-stage robotic arm and the second-stage robotic arm is the target joint, and the second-stage robotic arm can be controlled to rotate uniformly in the counterclockwise direction with the target joint as the center. At this time, the position of the target arm and the measurement value of the torque sensor corresponding to the target joint can be recorded every time a motion cycle (the motion cycle can be within 30 to 50ms).

[0054] After recording the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each movement cycle, the first position data set of the target arm corresponding to the maximum or minimum measurement value can be extracted from the recorded data, and the target position of the target arm can be obtained based on the first position data set.

[0055] Specifically, when the gravity is directed downward, the gravity generated by the target arm is a vector passing through the center of mass of the forearm and pointing vertically downward. During the movement of the forearm, the center of mass of the forearm moves in a circular motion. The horizontal distance between the center of mass of the forearm and the axis of the target joint, i.e., the force arm, changes with the position and can be expressed by the following formula:

[0056] T r =mg*l(q), (1)

[0057] Among them, T r is the true torque value, m is the load mass, and l(q) is the lever arm. When the distance between the center of mass of the forearm and the axis of the target joint is the farthest, that is, when the lever arm l(q) is the largest, the torque generated at the target joint is the largest, that is, T r The absolute value of is the largest. Among them, the actual torque value and the measured value of the torque sensor satisfy the following formula:

[0058] T-T0=T r , (2)

[0059] Wherein, T is the measured value of the torque sensor, and T0 is the offset of the torque sensor.

[0060] According to formula (2), T r The absolute value of T is the largest and r >0, T takes the maximum value, T r The absolute value of T is the largest and r When <0, T takes the minimum value. At the same time, since the position of the target arm and the measured value of the torque sensor are recorded simultaneously, when T takes the maximum or minimum value, the corresponding first position data set of the target arm can be directly extracted. For example, the first position data set of the target arm corresponding to when T takes the maximum value can be extracted, wherein the first position data set can be composed of a plurality of first position data, and the first position data can be the angle (between 0° and 360°) of rotation of the target arm from the initial position to the position of the target arm corresponding to when T takes the maximum value, or the angle (between 0° and 360°) of rotation of the target arm from the initial position to the position of the target arm corresponding to when T takes the minimum value.

[0061] Further, an average is taken for each first position data in the first position data set to obtain the target position of the target arm.

[0062] According to an embodiment of the present invention, the second control module 300 is specifically used to control the target arm to rotate 90° counterclockwise or clockwise at the target position, so that the target arm moves to a second position where the force arm is equal to zero.

[0063] When the target arm is at the target position, the target arm can be controlled to rotate 90° counterclockwise or clockwise at the target position to move the target arm to the second position where the force arm is equal to zero. At this time, according to formula (1), since the force arm l(q) is equal to 0, the true torque value T r = 0, then, combined with formula (2), we know that T = T0. That is, after the target arm is controlled to rotate 90° counterclockwise or clockwise at the target position, the measured value of the torque sensor corresponding to the second position of the target arm is the offset of the torque sensor.

[0064] In one embodiment of the present invention, after obtaining the bias of the torque sensor, when the forearm of the robot is controlled to move to the third position, the first-order gravity torque of the corresponding load can be calculated according to the bias of the torque sensor by the following formula:

[0065] mgl(q i )=T-T0 (3)

[0066] Among them, l(q i ) is the force arm corresponding to the robot's forearm in the third position.

[0067] Therefore, the present invention can calibrate the torque sensor by controlling the robot's mechanical arm to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and operation complexity and improving the calibration efficiency.

[0068] According to the torque sensor calibration system of the robot joint of the embodiment of the present invention, the target arm corresponding to the target joint is controlled to move at a constant speed along the preset direction by the first control module, and the position of the target arm and the measurement value of the torque sensor corresponding to the target joint are recorded after each movement cycle, and the first position data set of the target arm corresponding to the maximum or minimum measurement value is extracted by the first acquisition module, and the target position of the target arm is obtained according to the first position data set, and the target arm is controlled to move to the second position where the force arm is equal to zero according to the target position by the second control module, and the bias of the torque sensor is obtained according to the second position by the second acquisition module. Therefore, the calibration of the torque sensor can be achieved by controlling the robot's mechanical arm to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and the complexity of the operation, and improving the calibration efficiency.

[0069] Corresponding to the above embodiment, the present invention also provides a computer device.

[0070] The computer device of the embodiment of the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned torque sensor calibration method for the robot joint is implemented.

[0071] According to the computer device of an embodiment of the present invention, when the processor executes the computer program stored in the memory, the torque sensor can be calibrated by controlling the robot's mechanical arm to perform corresponding movements without adding additional load, thereby greatly reducing the calibration time and operation complexity and improving the calibration efficiency.

[0072] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0075] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0076] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0077] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0078] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0079] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for calibrating a torque sensor of a robot joint, characterized in that: The following steps are involved: Controlling the target arm corresponding to the target joint to move at a constant speed along a preset direction, and recording the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each movement cycle; wherein, before controlling the target arm corresponding to the target joint to move at a constant speed along the preset direction, adjusting the posture of the target joint of the robot so that the axis of the target joint is perpendicular to the gravity direction of the target arm, so that the target arm becomes the load of the target joint; Extracting a first position data set of the target arm corresponding to when the measured value is maximum or minimum, and acquiring a target position of the target arm according to the first position data set; Controlling the target arm to move to a second position where the force arm is equal to zero according to the target position; wherein, controlling the target arm to move to the second position where the force arm is equal to zero according to the target position comprises: controlling the target arm to rotate 90° counterclockwise or clockwise at the target position so that the target arm moves to the second position where the force arm is equal to zero; An offset of the torque sensor is obtained according to the second position.

2. The method for calibrating a torque sensor of a robot joint according to claim 1, characterized in that: Before controlling the target arm corresponding to the target joint to move at a uniform speed along the preset direction, the method further includes: For the joints connecting the robot and the base, the robot is mounted on a horizontal base for calibration.

3. The method for calibrating a torque sensor of a robot joint according to any one of claims 1 and 2, characterized in that: Acquiring the target position of the target arm according to the first position data set includes: calculating an average value of each first position data in the first position data set to acquire the target position of the target arm.

4. The method for calibrating a torque sensor of a robot joint according to claim 1, characterized in that: Also includes: The first-order gravity moment of the target joint is calculated according to the bias of the torque sensor, and gravity compensation is performed on the target joint according to the first-order gravity moment.

5. The method for calibrating a torque sensor of a robot joint according to claim 4, characterized in that: Before controlling the target arm corresponding to the target joint to move at a uniform speed along the preset direction, the method further includes: performing zero position calibration on each joint of the robot.

6. The method for calibrating a torque sensor of a robot joint according to claim 5, characterized in that: The speed of the uniform motion is within a range of 5 degrees / s to 10 degrees / s.

7. A robot joint torque sensor calibration system, characterized in that: include: A first control module, wherein the first control module is used to control the target arm corresponding to the target joint to move at a constant speed along a preset direction, and to record the position of the target arm and the measurement value of the torque sensor corresponding to the target joint after each movement cycle; wherein, before controlling the target arm corresponding to the target joint to move at a constant speed along the preset direction, the first control module adjusts the posture of the target joint of the robot so that the axis of the target joint is perpendicular to the gravity direction of the target arm, so that the target arm becomes the load of the target joint; A first acquisition module, the first acquisition module is used to extract a first position data set of the target arm corresponding to when the measured value is maximum or minimum, and acquire the target position of the target arm according to the first position data set; a second control module, the second control module being used to control the target arm to move to a second position where the force arm is equal to zero according to the target position; wherein the second control module is specifically used to: control the target arm to rotate 90° counterclockwise or clockwise at the target position so that the target arm moves to the second position where the force arm is equal to zero; A second acquisition module, wherein the second acquisition module is used to acquire the bias of the torque sensor according to the second position.

8. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the torque sensor calibration method for the robot joint according to any one of claims 1-6 is implemented.

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