A robotic arm for a six-degree-of-freedom visual grasping system and a self-calibration method thereof

Abstract

The present invention discloses a mechanical arm of a six-degree-of-freedom visual grasping system and a self-calibration method thereof, wherein the mechanical arm comprises a first rotation axis, a lifting axis, a telescopic axis, a second rotation axis, a roll axis, a pitch axis and an end effector connected in sequence, and the end effector has six degrees of freedom in space; the mechanical arm self-calibration method comprises: constructing a local coordinate system of the end effector, and performing axis zero position calibration on the roll axis and the pitch axis at the end of the mechanical arm; constructing a spatial coordinate system of the mechanical arm, and performing axis zero position calibration on the first rotation axis, the lifting axis, the telescopic axis and the second rotation axis of the mechanical arm. The present invention relies on its own sensors to complete the self-calibration process, without the need to use external professional measuring devices, thereby reducing the cost of zero position calibration of the mechanical arm.

Description

Technical Field

[0001] The present invention relates to the technical field of robot error calibration, and in particular to a robot arm of a six-degree-of-freedom visual grasping system and a self-calibration method thereof. Background Art

[0002] The mainstream calibration methods of visual grasping systems have the following main problems.

[0003] 1. Dependence on additional equipment and professional engineers. Among the current zero-position calibration methods, some require the use of professional calibration equipment, such as laser trackers, motion capture systems, etc. These devices are expensive and require professional engineers to operate and maintain them.

[0004] 2. The operation is complicated and consumes a lot of manpower and material resources. The zero calibration method using calibration equipment usually needs to be carried out on-site, which is complicated and consumes a lot of manpower and material resources. This increases the operating costs of the enterprise and reduces production efficiency. Summary of the invention

[0005] Technical purpose: In view of the defects in the prior art, the present invention discloses a robotic arm of a six-degree-of-freedom visual grasping system and a self-calibration method thereof.

[0006] Technical solution: In order to achieve the above technical objectives, the present invention adopts the following technical solution.

[0007] A method for self-calibration of a manipulator of a six-degree-of-freedom visual grasping system, wherein the manipulator comprises a first rotation axis, a lifting axis, a telescopic axis, a second rotation axis, a rolling axis, a pitching axis and an end effector connected in sequence, and the end effector has six degrees of freedom in space; the manipulator moves to a working platform and realizes zero-position self-calibration through a calibration plate on a calibration area;

[0008] The robot arm self-calibration method includes the following steps:

[0009] S1. Construct the local coordinate system frame_end of the end effector. The position of the end effector is O end , the forward direction of the robot arm is X end , the vertical downward direction is Z end , the Y axis follows the right-hand rule, where the plane where the end effector is located is plane_end; the roll axis and pitch axis at the end of the robot arm are calibrated to zero position;

[0010] S2. Construct the spatial coordinate system of the robot arm. The spatial coordinate system of the robot arm follows the right-hand coordinate system principle. The coordinate origin is the center of the first rotation axis, the Z axis is the direction of the lifting axis, the X axis is the forward direction of the first rotation axis, and the Y axis follows the right-hand rule; calibrate the first rotation axis, lifting axis, telescopic axis, and second rotation axis of the robot arm.

[0011] Preferably, S1 comprises the following steps:

[0012] S1.1, control the end effector to move to the calibration area, collect the distance information between the end effector and the calibration plate through the distance sensor, obtain the data d1, d2, and d3 of the three distance sensors in turn, construct the plane plane_end where the end effector is located, and thus obtain the position relationship between the plane plane_end where the end effector is located and the plane plane_base of the calibration plate;

[0013] S1.2. Get the normal vector of the calibration plate plane plane_base Get the normal vector Projection n_base on the YOZ plane YOZ The angle with the Y axis is taken as the roll angle deviation Δroll; get the normal vector Projection n_base on the XOZ plane XOZ The angle with the X axis is taken as the pitch angle deviation Δpitch;

[0014] S1.3. According to the calculated angular deviation Δroll and angular deviation Δpitch, the motors of the roll axis and the pitch axis are adjusted through the servo control algorithm so that the angular deviation between the plane plane_end where the end effector is located and the plane plane_base of the calibration plate is less than the threshold. The motor value corresponding to the current position of the calibration is the actual zero position of the roll axis and the pitch axis.

[0015] Preferably, the calculation formulas for the roll angle deviation Δroll and the pitch angle deviation Δpitch include:

[0016]

[0017] in, is the normal vector of the YOZ plane in the frame_end coordinate system, is the normal vector of the XOZ plane of the frame_end coordinate system, is the normal vector of the calibration plate plane plane_base.

[0018] Preferably, S2 comprises the following steps:

[0019] S2.1. The end effector moves to the theoretical target point position according to the issued command, and obtains the theoretical control quantities of the first rotation axis, lifting axis, telescopic axis, and second rotation axis according to the inverse kinematics model of the manipulator;

[0020] S2.2, after obtaining the control to control the end effector to move to the new space value, the lifting axis calibration zero position is solved in combination with the theoretical target point position;

[0021] S2.3, after obtaining the center of the end effector and the center of the calibration plate through visual image recognition technology, solve the calibration zero position of the first rotation axis, the telescopic axis, and the second rotation axis;

[0022] S2.4, respectively control the first rotation axis, telescopic axis, and second rotation axis to move to the calibration zero position, and set the current position as the calibration zero position of the first rotation axis, lifting axis, telescopic axis, second rotation axis, roll axis, and pitch axis.

[0023] Preferably, after obtaining the control to control the end effector to move to a new spatial value in S2.2, solving the zero position of the lifting axis calibration in combination with the theoretical target point position and posture includes:

[0024] Get the distance sensor data d1, d2, d3, the actual distance d between the current end effector and the calibration plate a The calculation formula is:

[0025]

[0026] Then the control deviation of lifting axis 2 is Δd=d a -d0; Control the end effector to move to the new space value P′ z , P′ z =P z +Δd, record the current control amount of lifting axis 2 as l 2_c ; Then the calibration zero position of lifting axis 2 is:

[0027] l 2_zero = l 2_c -l 2_0 .

[0028] Preferably, in S2.3, after obtaining the center of the end effector and the center of the calibration plate by visual image recognition technology, solving the calibration zero position of the first rotation axis, the telescopic axis, and the second rotation axis includes:

[0029] The visual camera takes a picture and calculates the deviation value Δv={Δx, Δy, Δyaw} between the center of the end effector and the center of the calibration plate through visual image recognition technology. The visual servo technology is used to control the movement of the end effector according to the deviation value. When Δv is less than the set threshold, the actual control amount of the current first rotation axis, telescopic axis, and second rotation axis is obtained as (θ 1_c , l 3_c ,θ 4_c ) T ; Solve the calibration zero position of the first rotation axis, telescopic axis, and second rotation axis as:

[0030] (θ 1_zero , l 3_zero ,θ 4_zero )=(θ 1_c , l3_c ,θ 4_c )-(θ 1_0 , l 3_0 ,θ 4_0 ).

[0031] A robotic arm of a six-degree-of-freedom visual grasping system is used for zero-position calibration according to any of the above-mentioned robotic arm self-calibration methods for a six-degree-of-freedom visual grasping system, wherein the robotic arm comprises a first rotation axis, a lifting axis, a telescopic axis, a second rotation axis, a roll axis, a pitch axis and an end effector connected in sequence, and the end effector has six degrees of freedom in space; the robotic arm moves to a working platform and realizes zero-position self-calibration through a calibration plate on a calibration area; a local coordinate system of the end effector is constructed to realize zero-position calibration of the roll axis and the pitch axis at the end of the robotic arm; a spatial coordinate system of the robotic arm is constructed, and the spatial coordinate system of the robotic arm follows the right-hand coordinate system principle to realize zero-position calibration of the first rotation axis, lifting axis, telescopic axis and second rotation axis of the robotic arm.

[0032] Beneficial effects: The present invention only relies on its own sensors to complete the self-calibration process, does not require the use of external professional measuring devices, does not require professional engineering personnel, is simple to operate, and has a fast calibration process, which reduces the financial, material and time costs of calibrating the zero position of the robotic arm, and has multiple calibration parameters, thereby improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The mechanical arm structure of the present invention is schematically shown in FIG. Figure 1 ;

[0034] Figure 2 The mechanical arm structure of the present invention is schematically shown in FIG. Figure 2 ;

[0035] Figure 3 is a schematic diagram of a local coordinate system of an end effector of the present invention;

[0036] Figure 4 It is a schematic plan view of the calibration plate of the present invention;

[0037] Figure 5 is a flow chart of a method according to an embodiment of the present invention;

[0038] Figure 6 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] As attached Figure 6 As shown, a method for self-calibration of a robot arm of a six-degree-of-freedom visual grasping system of the present invention comprises:

[0041] S1. Construct the local coordinate system frame_end of the end effector. The position of the end effector is O end , the forward direction of the robot arm is X end , the vertical downward direction is Z end , the Y axis follows the right-hand rule, where the plane where the end effector is located is plane_end; the roll axis and pitch axis at the end of the robot arm are calibrated to zero position;

[0042] S2. Construct the spatial coordinate system of the robot arm. The spatial coordinate system of the robot arm follows the right-hand coordinate system principle. The coordinate origin is the center of the first rotation axis, the Z axis is the direction of the lifting axis, the X axis is the forward direction of the first rotation axis, and the Y axis follows the right-hand rule; calibrate the first rotation axis, lifting axis, telescopic axis, and second rotation axis of the robot arm.

[0043] The present invention is further described below with reference to the embodiments.

[0044] Example:

[0045] As attached Figure 5 As shown, a self-calibration method for a robotic arm of a six-degree-of-freedom visual grasping system of the present invention is provided, wherein the robotic arm comprises a first rotation axis 1, a lifting axis 2, a telescopic axis 3, a second rotation axis 4, a roll axis 5, a pitch axis 6 and an end effector connected in sequence, and the end effector has six degrees of freedom in space (x, y, z, roll, pitch, yaw), corresponding to the coordinates of the three directions of xyz in the spatial coordinate system of the robotic arm and the roll angle, pitch angle and heading angle; the spatial coordinate system of the robotic arm is constructed, and the spatial coordinate system of the robotic arm follows the right-hand coordinate system principle, such as Figure 1As shown, the coordinate origin is the center of the first rotating axis 1, the Z axis is the direction of the lifting axis 2, the X axis is the forward direction of the first rotating axis 1, and the Y axis follows the right-hand rule; the robot moves to the working platform and realizes zero-position self-calibration through the calibration plate on the calibration area; the calibration area is set on the working platform, and the reference point P is a fixed position in the coordinate system; the end effector is located at the end of the robot arm, and a visual camera and three distance sensors are installed on the end effector, and the end effector, the visual camera, and the three distance sensors are on the same plane; wherein, the first rotating axis 1 realizes rotation in the Z-axis direction, the lifting axis 2 realizes the lifting amount in the Z-axis direction, the telescopic axis 3 realizes the movement amount in the X and Y directions, the second rotating axis 4 realizes rotation in the Z-axis direction, the roll axis 5 realizes rotation in the X-axis direction, and the pitch axis 6 realizes rotation in the Y-axis direction;

[0046] The robot arm self-calibration method includes the following steps:

[0047] S1. Construct the local coordinate system frame_end of the end effector. The position of the end effector is O end , the forward direction of the robot arm is X end , the vertical downward direction is Z end , the Y axis follows the right-hand rule, where the plane where the end effector is located is plane_end; the roll axis 5 and the pitch axis 6 at the end of the robot arm are calibrated to zero position; the following steps are included:

[0048] S1.1, as attached Figure 3 As shown, the end effector is controlled to move to the calibration area, the distance information between the end effector and the calibration plate is collected through the distance sensor, the data d1, d2, and d3 of the three distance sensors are obtained in sequence, and the plane plane_end where the end effector is located is constructed, so as to obtain the position relationship between the plane plane_end where the end effector is located and the plane plane_base of the calibration plate;

[0049] Among them, the local coordinate system frame_end is established based on the plane plane_end where the end effector is located, such as Figure 4 As shown, the distance sensor on the plane plane_end where the end effector is located is known. Then the spot of the distance sensor on the calibration plate plane plane_base, that is, when the distance sensor is emitted from the end effector plane to the calibration plate plane, the coordinates in the end effector coordinate system frame_end are: D1 = (x1, y1, d1), D2 = (x2, y2, d2), D3 = (x3, y3, d3), where (x1, y1), (x2, y2), (x3, y3) are the installation coordinates of the three distance sensors on the end effector respectively; construct the plane plane_end where the end effector is located according to D1, D2, D3;

[0050] S1.2. Get the normal vector of the calibration plate plane plane_base Get the normal vector Projection n_base on the YOZ plane YOZ The angle with the Y axis is taken as the roll angle deviation Δroll; get the normal vector Projection n_base on the XOZ plane XOZ The angle with the X axis is taken as the pitch angle deviation Δpitch;

[0051] Constructing space vectors and space vector Then the normal vector of the calibration plate plane plane_base

[0052] It is known that the normal vector of the YOZ plane in the frame_end coordinate system is The calculation formula of the roll angle deviation Δroll is:

[0053]

[0054] It is known that the normal vector of the XOZ plane of the frame_end coordinate system is The calculation formula of the pitch angle deviation Δpitch is:

[0055]

[0056] S1.3. According to the calculated angular deviation Δroll and angular deviation Δpitch, the motors of the roll axis and the pitch axis are adjusted by the servo control algorithm so that the angular deviation between the plane plane_end where the end effector is located and the plane plane_base of the calibration plate is less than the threshold value. The motor value corresponding to the current position is calibrated to be the actual zero position of the roll axis and the pitch axis; in some embodiments of the present invention, the servo calibration algorithm can be implemented by the PID control algorithm or the open-loop control algorithm in the prior art.

[0057] S2. Construct the spatial coordinate system of the robot arm. The spatial coordinate system of the robot arm follows the principle of the right-hand coordinate system. The origin of the coordinate is the center of the first rotating axis 1, the Z axis is the direction of the lifting axis 2, the X axis is the front direction of the first rotating axis 1, that is, the front direction of the robot arm, and the Y axis follows the right-hand rule; calibrate the first rotating axis 1, the lifting axis 2, the telescopic axis 3, and the second rotating axis 4 of the robot arm; including the following steps:

[0058] S2.1, as attached Figure 1 , Attachment Figure 2 and attached Figure 4As shown, the end effector sends instructions to the theoretical target point position, and obtains the theoretical control quantities of the first rotation axis, lifting axis, telescopic axis, and second rotation axis according to the inverse kinematics model of the manipulator;

[0059] The end effector moves to the theoretical target point position (theoretical coordinates of the center of the calibration plate) P according to the issued command. aim =(P x , P y , P z , P yaw ,0,0) T , corresponding to the coordinates of the three directions xyz in the space coordinate system of the robot arm and the roll angle, pitch angle and heading angle, P aim That is to say, Figure 4 The reference point P in the figure is: The theoretical control quantities of the first rotating axis 1, the lifting axis 2, the telescopic axis 3, and the second rotating axis 4 are:

[0060] (θ 1_0 , l 2_0 , l 3_0 ,θ 4_0 ) T =InverseKinematic(P aim )

[0061] Among them, InverseKinematic() represents the inverse kinematics model of the robot arm, which is used to describe the relationship between the end position and each joint of the robot arm. The theoretical control amount of the lifting axis 2 is l 2_0 It can be represented by the distance sensor data d0, that is, the lifting axis 2 is at l 2_0 When the position is 0, the theoretical reading of the distance sensor is d0; after the zero position of the roll axis and the pitch axis is calibrated in step S1, the values ​​of the three distance sensors are the same.

[0062] S2.2, obtain control After the end effector moves to the new spatial value, combine the theoretical target point position to solve the zero position of the lifting axis 2 calibration. Get the distance sensor data d1, d2, d3 at this time, and the actual distance d between the current end effector and the calibration plate a The calculation formula is:

[0063]

[0064] Then the control deviation of lifting axis 2 is Δd=d a -d0. The end effector is controlled by lifting axis 2 to move to the new spatial value P' z , that is, the end effector moves in the Z-axis direction Δd, P′ z =P z +Δd, record the current control amount of lifting axis 2 as l 2_c The calibration zero position of lifting axis 2 is:

[0065] l 2_zero = l 2_c -l 2_0

[0066] S2.3. After obtaining the center of the end effector and the center P of the calibration plate through visual image recognition technology, solve the calibration zero position of the first rotation axis 1, telescopic axis 3, and second rotation axis 4. The visual camera takes a picture and calculates the deviation value Δv={Δx, Δy, Δyaw} between the center of the end effector and the center P of the calibration plate through visual image recognition technology. The movement of the end effector is controlled according to the deviation value using visual servo technology. Visual servo technology is an existing technology and will not be described in detail here. When Δv is less than the set threshold, the actual control amount of the current first rotation axis 1, telescopic axis 3, and second rotation axis 4 is obtained as (θ 1_c , l 3_c ,θ 4_c ) T The calibration zero position of the first rotating axis 1, the telescopic axis 3, and the second rotating axis 4 is solved as follows:

[0067] (θ 1_zero , l 3_zero ,θ 4_zero )=(θ 1_c , l 3_c ,θ 4_c )-(θ 1_0 , l 3_0 ,θ 4_0 )

[0068] S2.4, respectively control the first rotation axis 1, telescopic axis 3, and second rotation axis 4 to move to the calibration zero position, and set the current position as the calibration zero position of the first rotation axis 1, lifting axis 2, telescopic axis 3, second rotation axis 4, rolling axis 5, and pitch axis 6.

[0069] The present invention also discloses a robotic arm of a six-degree-of-freedom visual grasping system, which is used for zero-position calibration according to the robotic arm self-calibration method of a six-degree-of-freedom visual grasping system described above. The robotic arm includes a first rotation axis, a lifting axis, a telescopic axis, a second rotation axis, a roll axis, a pitch axis and an end effector connected in sequence, and the end effector has six degrees of freedom in space. The robotic arm moves to a working platform and realizes zero-position self-calibration through a calibration plate on a calibration area; a local coordinate system of the end effector is constructed to realize zero-position calibration of the roll axis 5 and the pitch axis 6 at the end of the robotic arm; and a spatial coordinate system of the robotic arm is constructed. The spatial coordinate system of the robotic arm follows the right-hand coordinate system principle and is used to realize zero-position calibration of the first rotation axis 1, lifting axis 2, telescopic axis 3, and second rotation axis 4 of the robotic arm.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for self-calibration of a robotic arm of a six-degree-of-freedom visual grasping system, characterized in that: The mechanical arm comprises a first rotating axis, a lifting axis, a telescopic axis, a second rotating axis, a rolling axis, a pitching axis and an end effector which are connected in sequence, and the end effector has six degrees of freedom in space; the mechanical arm moves to the working platform and realizes zero position self-calibration through the calibration plate on the calibration area; The robot arm self-calibration method includes the following steps: S1. Construct the local coordinate system frame_end of the end effector. The position of the end effector is O end , the forward direction of the robot arm is X end , the vertical downward direction is Z end , the Y axis follows the right-hand rule, where the plane where the end effector is located is plane_end; the roll axis and pitch axis at the end of the robot arm are calibrated to zero position; S1 includes the following steps: S1.1, control the end effector to move to the calibration area, collect the distance information between the end effector and the calibration plate through the distance sensor, obtain the data d1, d2, and d3 of the three distance sensors in turn, construct the plane plane_end where the end effector is located, and thus obtain the position relationship between the plane plane_end where the end effector is located and the plane plane_base of the calibration plate; S1.

2. Get the normal vector of the calibration plate plane plane_base Get the normal vector Projection n_base on the YOZ plane YOZ The angle with the Y axis is taken as the roll angle deviation Δroll; get the normal vector Projection n_base on the XOZ plane XOZ The angle with the X axis is taken as the pitch angle deviation Δpitch; S1.

3. According to the calculated angular deviation Δroll and angular deviation Δpitch, the motors of the roll axis and the pitch axis are adjusted through the servo control algorithm so that the angular deviation between the plane plane_end where the end effector is located and the plane plane_base of the calibration plate is less than the threshold value; the motor value corresponding to the current position is calibrated to be the actual zero position of the roll axis and the pitch axis; S2. Construct the spatial coordinate system of the robot arm. The spatial coordinate system of the robot arm follows the right-hand coordinate system principle. The origin of the coordinate is the center of the first rotation axis, the Z axis is the lifting axis direction, the X axis is the front direction of the first rotation axis, and the Y axis follows the right-hand rule; calibrate the first rotation axis, lifting axis, telescopic axis, and second rotation axis of the robot arm; S2 includes the following steps: S2.

1. The end effector moves to the theoretical target point position according to the issued command, and obtains the theoretical control quantities of the first rotation axis, lifting axis, telescopic axis, and second rotation axis according to the inverse kinematics model of the manipulator; S2.2, after controlling the end effector to move to the new spatial value, the lifting axis calibration zero position is solved in combination with the theoretical target point position; S2.3, after obtaining the center of the end effector and the center of the calibration plate through visual image recognition technology, solve the calibration zero position of the first rotation axis, the telescopic axis, and the second rotation axis; S2.4, respectively control the first rotation axis, telescopic axis, and second rotation axis to move to the calibration zero position, and set the current position as the calibration zero position of the first rotation axis, lifting axis, telescopic axis, second rotation axis, roll axis, and pitch axis.

2. The method for self-calibration of a robotic arm of a six-degree-of-freedom visual grasping system according to claim 1, characterized in that: The calculation formulas for the roll angle deviation Δroll and the pitch angle deviation Δpitch include: in, is the normal vector of the YOZ plane in the frame_end coordinate system, is the normal vector of the XOZ plane of the frame_end coordinate system, is the normal vector of the calibration plate plane plane_base.

3. The method for self-calibration of a robotic arm of a six-degree-of-freedom visual grasping system according to claim 1, characterized in that: After the end effector is controlled to move to the new spatial value in S2.2, the zero position of the lifting axis calibration is solved in combination with the theoretical target point position, including: Get the distance sensor data d1, d2, d3, the actual distance d between the current end effector and the calibration plate a The calculation formula is: Then the control deviation of the lifting axis is Δd = d a -d0; Control the end effector to move to the new space value P′ z , P′ z =P z +Δd, record the current control amount of the lifting axis as l 2_c , P z is the z-axis coordinate in the theoretical target point position; then the zero position of the lifting axis is solved as: l 2_zero ＝l 2_c -l 2_0 Among them, l 2_0 is the theoretical control amount of the lifting axis. 2_0 When the position is , the distance sensor theoretically reads d0.

4. The method for self-calibration of a robot arm of a six-degree-of-freedom visual grasping system according to claim 1, characterized in that: In S2.3, the center of the end effector and the center of the calibration plate are obtained by visual image recognition technology, and then the calibration zero positions of the first rotation axis, the telescopic axis, and the second rotation axis are solved, including: The visual camera takes pictures and calculates the deviation value Δv between the end effector center and the calibration plate center P through visual image recognition technology. The visual servo technology is used to control the movement of the end effector according to the deviation value. When Δv is less than the set threshold, the actual control amount of the current first rotation axis, telescopic axis, and second rotation axis is obtained as (θ 1_c , l 3_c ,θ 4_c ) T ; Solve the calibration zero position of the first rotation axis, telescopic axis, and second rotation axis as: (i 1_zero ,l 3_zero ,the 4_zero )=(θ 1_c ,l 3_c ,the 4_c )-(θ 1_0 ,l 3_0 ,the 4_0 ) Among them, θ 1_0 , l 3_0 ,θ 4_0 They are the theoretical control quantities of the first rotation axis, telescopic axis, and second rotation axis respectively.

5. A robotic arm of a six-degree-of-freedom visual grasping system, used for zero-position calibration according to a robotic arm self-calibration method of a six-degree-of-freedom visual grasping system according to any one of claims 1 to 4, characterized in that: The robotic arm includes a first rotating axis, a lifting axis, a telescopic axis, a second rotating axis, a roll axis, a pitch axis and an end effector connected in sequence, and the end effector has six degrees of freedom in space; the robotic arm moves to a working platform and realizes zero-position self-calibration through a calibration plate on a calibration area; a local coordinate system of the end effector is constructed to realize zero-position calibration of the roll axis and the pitch axis at the end of the robotic arm; and a spatial coordinate system of the robotic arm is constructed, and the spatial coordinate system of the robotic arm follows the right-hand coordinate system principle, and is used to realize zero-position calibration of the first rotating axis, the lifting axis, the telescopic axis and the second rotating axis of the robotic arm.

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