Mechanical arm static rigidity testing device and testing method

Abstract

The invention discloses a mechanical arm static rigidity testing device and method. The mechanical arm static rigidity testing device comprises a testing tool, a contact device, a laser tracker and an information processing and control device. The testing tool comprises a supporting device, a pressurizing device and a force collecting device. The supporting device is used for fixing the tested mechanical arm, the laser tracker and the pressurizing device; the pressurizing device is used for providing loads in six directions, so that the mechanical arm deforms; the force acquisition device is used for measuring a load value acting on the mechanical arm; the contact device is used for enabling the stress direction of the mechanical arm to be consistent with the measurement direction of the force acquisition device; the laser tracker is used for measuring the deformation quantity of the mechanical arm; and the information processing and control device is used for controlling the pressurizing device to apply a load to the mechanical arm and processing measurement information of the force acquisition device and the laser tracker to obtain static stiffness data of the mechanical arm. Rigidity tests in six directions can be carried out only through one-time reversing, operation is easy, and multi-direction tests are met.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical property detection, and particularly relates to a static stiffness test device and test method for a robotic arm. Background Art

[0002] The static stiffness of a robotic arm describes the relationship between the position change of its end effector and the external force when the robotic arm is subjected to an external force. Static stiffness is an important parameter in the design and performance evaluation of a robotic arm. The static stiffness of a robotic arm is an important indicator to measure its static performance. A robotic arm with high static stiffness has less deformation when subjected to an external force, so it can maintain high positioning accuracy and repeatability; a robotic arm with high static stiffness can better control vibration and displacement during rapid movement, thereby improving dynamic response and control accuracy; this is crucial for application scenarios such as high-precision and micro-operation. Therefore, it is necessary to accurately measure the static stiffness of the robotic arm joints and the whole machine during the design verification stage to verify the simulation results, so as to guide the design and improvement of the robotic arm and improve its overall performance. Chinese Patent CN 116242599 A discloses a test method and system for the static stiffness of a robotic arm. The disadvantages of this patented method are: this test method and device can only perform one-way stiffness testing. When performing multi-directional stiffness testing, it needs to be repeatedly disassembled and assembled, and the posture adjustment is complex, with low efficiency; moreover, the accuracy of the test tooling is low, and the static stiffness data of the robotic arm cannot be accurately measured. Summary of the Invention

[0003] To solve the above problems, the present invention provides a static stiffness test device and test method for a robotic arm.

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

[0005] A static stiffness test device for a robotic arm includes a test tooling, a contact device, a laser tracker, and an information processing and control device;

[0006] The test tooling includes a support device, a pressurizing device, and a force acquisition device;

[0007] The support device is used to fix the robotic arm to be tested, the laser tracker, and the pressurizing device;

[0008] The pressurizing device is used to provide loads in six directions of X+, X-, Y+, Y-, Z+, and Z- to deform the robotic arm;

[0009] The force acquisition device is installed on the pressurizing device and is used to measure the load values in six directions of X+, X-, Y+, Y-, Z+, and Z- acting on the robotic arm;

[0010] The contact device is installed at the end of the robotic arm to be tested and is connected to the force acquisition device, and is used to make the force direction of the robotic arm consistent with the measurement direction of the force acquisition device;

[0011] A laser tracker is used to measure the deformation of the robotic arm.

[0012] The information processing and control device is used to control the pressurizing device to apply a load to the robotic arm, and process the measurement information of the force acquisition device and the laser tracker to obtain the static stiffness data of the robotic arm.

[0013] Furthermore, the pressurizing device includes a rectangular pressurizing frame, electric push rods, first X-direction chutes, Y-direction chutes, first locking sliders, a tooling table, and electric lifting columns; the electric lifting columns are vertically fixed on the supporting device, and their telescopic ends are connected to the tooling table; two first X-direction chutes and two Y-direction chutes are respectively and parallelly fixed on the four sides of the tooling table along the X-axis direction and the Y-axis direction; the rectangular pressurizing frame is slidably and lockingly connected to the first X-direction chutes or Y-direction chutes respectively through the first locking sliders; the telescopic ends of two electric push rods are opposite and symmetrically installed inside the rectangular pressurizing frame, and the telescopic ends of the two electric push rods and the upper and lower inner sides of the rectangular pressurizing frame are all connected to the force acquisition device. It realizes the function of performing stiffness tests in six directions of X+, X-, Y+, Y-, Z+, and Z- with only a single commutation; and by setting the chutes and locking sliders, the front and back positions of the rectangular pressurizing frame can also be adjusted to make the spherical surface of the spherical part of the robotic arm to be measured in radial contact with the test planes of the four pressure sensors, improving the measurement accuracy and precision.

[0014] Furthermore, the rectangular pressurizing frame includes a fixed upper plate, a fixed bottom plate, and fixed side plates. The fixed upper plate and the fixed bottom plate are connected by two fixed side plates to form the rectangular pressurizing frame. The structure is simple and meets the multi-directional test requirements.

[0015] Furthermore, the force acquisition device includes four pressure sensors, where two pressure sensors are respectively fixedly connected to the telescopic ends of the two electric push rods of the pressurizing device, and the other two pressure sensors are respectively fixedly connected to the upper inner side and the lower inner side of the rectangular pressurizing frame of the pressurizing device. The operation is simple and meets the multi-directional test requirements.

[0016] Furthermore, the contact device includes a spherical part. One end of the spherical part is fixed on the robotic arm, and the spherical surface at the other end is in radial contact with the test planes of the four pressure sensors. It can make the force loading direction and the deformation measurement direction consistent, improving the load accuracy.

[0017] Furthermore, the spherical part includes a spherical part and a round rod part. One end of the round rod part is axially fixed at the end of the robotic arm to be measured, and the other end is fixedly connected to the spherical part. When the electric push rod applies a load, the robotic arm deforms, and the spherical surface of the spherical part rotates relative to the plane of the pressure sensor, which can make the force loading direction and the deformation measurement direction consistent, improving the load accuracy.

[0018] Further, the support device includes a base plate, two second X-direction chutes fixed on the base plate along the X-axis direction, a second locking slider, and a fixing column; the bottom of the fixing column is slidably and lockingly connected to the two second X-direction chutes through the second locking slider, and the top of the fixing column is used to fix the robotic arm to be tested. The distance between the robotic arm to be tested and the test fixture can be initially adjusted through the second X-direction chutes and the second locking slider, and then finely adjusted through the Y-direction chute or the first X-direction chute, improving the working efficiency of the test.

[0019] A method for testing the static stiffness of a robotic arm, using the above-mentioned device for testing the static stiffness of a robotic arm, specifically includes the following steps:

[0020] (1) Fix the robotic arm to be tested on the test fixture, place the laser tracker on one side of the test fixture, fix the spherical part on the robotic arm to be tested, and fix the target ball of the laser tracker on the spherical part.

[0021] (2) Make the rectangular pressurizing frame be slidably and lockingly connected to the first X-direction chute through the first locking slider; adjust the height of the tooling table through the electric lifting column, adjust the front and rear positions of the rectangular pressurizing frame through the first X-direction chute, so that the spherical surface of the spherical part of the robotic arm to be tested is in radial contact with the test planes of the four pressure sensors, and then lock the first locking slider; the information processing and control device controls the two electric push rods to extend, applying loads in the X+ and X- directions to the robotic arm to be tested, and the information processing and control device calculates the static stiffness data of the robotic arm to be tested in the X+ and X- directions according to the load values measured by the pressure sensors and the deformation amounts measured by the laser tracker.

[0022] (3) The information processing and control device controls the electric push rods to retract and the electric lifting column to rise, applying loads in the Z+ and Z- directions to the robotic arm to be tested, and the information processing and control device calculates the static stiffness data of the robotic arm to be tested in the Z+ and Z- directions according to the load values measured by the pressure sensors and the deformation amounts measured by the laser tracker.

[0023] (4) The information processing and control device controls the electric lifting column to descend, so that the rectangular pressurizing frame slides out of the first X-direction chute through the first locking slider and is slidably and lockingly connected to the Y-direction chute; adjust the height of the tooling table through the electric lifting column, adjust the front and rear positions of the rectangular pressurizing frame through the Y-direction chute, so that the spherical surface of the spherical part of the robotic arm to be tested is in radial contact with the test planes of the four pressure sensors, and then lock the first locking slider; the information processing and control device controls the two electric push rods to extend, applying loads in the Y+ and Y- directions to the robotic arm to be tested, and the information processing and control device calculates the static stiffness data of the robotic arm to be tested in the Y+ and Y- directions according to the load values measured by the pressure sensors and the deformation amounts measured by the laser tracker.

[0024] Further, the supporting device includes a base plate, two second X-direction chutes fixed on the base plate along the X-axis direction, a second locking slider, and a fixing column; the bottom of the fixing column is slidably and lockingly connected to the two second X-direction chutes through the second locking slider, and the top of the fixing column is used to fix the robotic arm to be measured.

[0025] In steps (2), (3), and (4), first, the distance between the robotic arm to be measured and the pressurizing device is preliminarily adjusted by adjusting the position of the fixing column on the second X-direction chute, and then the front-back position of the rectangular pressurizing frame is adjusted through the Y-direction chute or the first X-direction chute.

[0026] Further, the information processing and control device calculates the static stiffness data according to the following formula:

[0027] Ks = (F1 - F2) / (D1 - D2)

[0028] where,

[0029] Ks: static stiffness, kN / mm;

[0030] F1: the minimum load applied to the robotic arm to be measured, kN;

[0031] F2: the maximum load applied to the robotic arm to be measured, kN;

[0032] D1: the displacement of the robotic arm to be measured when the load is applied to F1, mm;

[0033] D2: the displacement of the robotic arm to be measured when the load is applied to F2, mm.

[0034] Advantages of the present invention:

[0035] 1. By adopting the test tooling, the stiffness tests in six directions of X+, X-, Y+, Y-, Z+, and Z- can be carried out with only a single commutation, and the operation is simple, meeting the multi-directional test requirements.

[0036] 2. By using a laser tracker for displacement measurement, the laser tracker is divided into two parts: a reflector (target ball) and a tracking head. The laser emitted by the tracking head hits the reflector and then reflects back to the tracking head. When the target moves, the tracking head adjusts the beam direction to align with the target, and at the same time, the detection system in the tracking head receives the returned beam to calculate the spatial position of the target. The moving distance is obtained through coordinate transformation without directly contacting the robot to be measured, reducing the error sources; the laser tracking instrument has high precision, fast measurement, and high test efficiency.

[0037] 3. By adopting the supporting device to rigidly connect the robot to be measured and the pressurizing device, the generation of relative displacement can be avoided, and the measurement error can be reduced.

[0038] 4. The force acquisition device is connected to the robotic arm to be measured through a contact device, ensuring that the direction of the applied load is along the measurement direction of the force sensor, improving the measurement accuracy and reducing the measurement error.

[0039] 5. This device can test the whole machine and also test the stiffness of components, with strong practicability. Description of the Drawings

[0040] Figure 1 It is a structural diagram of a robotic arm static stiffness testing device of the present invention.

[0041] Figure 2 It is a structural diagram of the test tooling of the present invention and a state diagram of the testing device performing X-direction testing.

[0042] Figure 3 It is a state diagram of the testing device of the present invention performing Y-direction testing.

[0043] Figure 4 It is a connection structural diagram of the force acquisition device and the pressurizing device of the present invention.

[0044] Figure 5 It is a flowchart of a robotic arm static stiffness testing method of the present invention. Detailed Embodiments

[0045] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings and preferred embodiments.

[0046] Embodiment 1

[0047] Refer to Figures 1-4 , this embodiment provides a robotic arm static stiffness testing device, including a test tooling 2, a contact device, a laser tracker 3 and an information processing and control device 4.

[0048] The test tooling includes a support device, a pressurizing device and a force acquisition device; the support device includes a base plate 16, second X-direction sliding grooves 11-3, second locking sliders 13-2 and fixing columns 5; the two second X-direction sliding grooves 11-3 are horizontally fixed on the left and right sides at the rear end of the base plate 16 along the X-axis direction by screws, and the fixing columns 5 are vertically fixed on the second locking sliders 13-2 by screws for fixedly connecting the robotic arm to be measured; the second locking sliders 13-2 slide in the second X-direction sliding grooves 11-3, and their relative movement and fixation with the base plate 16 can be achieved through manual locking to adjust the robotic arm or component to the measured posture, and it is compatible with the robotic arms or components to be measured with different lengths and arm spans. After adjusting to the appropriate position, lock the second locking sliders 13-2 to keep the robotic arm or component to be measured relatively fixed with the base plate 16, reducing the error caused by relative displacement during the test.

[0049] The pressurizing device includes a rectangular pressurizing frame, an electric push rod 9, a first X-direction chute 11-1, a Y-direction chute 11-2, a first locking slider 13-1, a tooling table 14, and an electric lifting column 15; the electric lifting column 15 is vertically fixed on the base plate 16 by screws, and its telescopic end faces upward and is fixedly connected to the tooling table 14 by screws; the tabletop of the tooling table 14 is set as a horizontal plane, and two first X-direction chutes 11-1 are fixedly parallel to the left and right sides of the tooling tabletop along the X-axis direction by screws, and two Y-direction chutes 11-2 are fixedly parallel to the front and back sides of the tooling tabletop along the Y-axis direction by screws.

[0050] The rectangular pressurizing frame is composed of a fixed upper plate 6, a fixed bottom plate 10, and two fixed side plates 12. The fixed upper plate 6 and the fixed bottom plate 10 are connected into a rectangular pressurizing frame through the two fixed side plates 12. The plate surfaces of the fixed upper plate 6 and the fixed bottom plate 10 are parallel to each other, the plate surfaces of the two fixed side plates 12 are parallel to each other, and the fixed upper plate 6, the fixed bottom plate 10, and the fixed side plates 12 can be connected by welding or screws, and the strength and stiffness need to meet the test requirements. The two fixed side plates 12 are fixedly connected to the first locking slider 13-1 by screws, and the first locking slider 13-1 can be slidably and lockingly connected to the first X-direction chute 11-1 or the Y-direction chute 11-2. The bottoms of the two electric push rods 9 are respectively fixed on the inner side surfaces of the two fixed side plates 12 by screws, and the telescopic ends of the two electric push rods 9 face each other and are symmetrically arranged inside the rectangular pressurizing frame.

[0051] In this embodiment, the force acquisition device is a pressure sensor 8. A total of 4 pressure sensors 8 are provided, and preferably its model is ZNLBM-IIX (Zhongnuo Transmitting Force). The test surfaces of two of the pressure sensors face each other and are respectively fixed on the telescopic ends of the two electric push rods 9, and the test surfaces of the other two pressure sensors face each other and are respectively fixed on the inner side surfaces of the fixed upper plate 6 and the fixed bottom plate 10.

[0052] In this embodiment, the contact device is a spherical part 7. The spherical part 7 is composed of a spherical ball and a round rod. One end of the round rod is axially fixed to the end of the mechanical arm to be measured through screws and an end flange, and the other end is threadedly connected to the spherical ball. The strength and stiffness of the spherical part 7 are greater than those of the mechanical arm to be measured to ensure that it only plays a role in transmitting the test load and does not affect the test accuracy.

[0053] Embodiment 2

[0054] Refer to Figure 5 , this embodiment provides a method for testing the stiffness of a robotic arm using the robotic arm static stiffness testing device described in Embodiment 1, which specifically includes the following steps:

[0055] (1) Fix the robotic arm 1 to be measured on the fixed column 5, fix the laser tracker 3 (not shown in the figure) on the base plate 16, fix the spherical part 7 on the robotic arm 1 to be measured, and bond and fix the target ball of the laser tracker to the spherical part 7 with hot melt adhesive; Slide and lock the rectangular pressing frame to the first X-direction chute 11-1 through the first locking slider 13-1;

[0056] (2) Adjust the position of the fixed column 5 on the second X-direction chute 11-3 through the second locking slider 13-2, initially adjust the distance between the robotic arm 1 to be measured and the test fixture, and then adjust the front and back position of the rectangular pressing frame in the first X-direction chute through the first locking slider 13-1; Then adjust the height of the tooling table 14 through the electric lifting column 15, so that the spherical surface of the spherical part 7 of the robotic arm to be measured is in radial contact with the test planes of the four pressure sensors, and then lock the first locking slider 13-1;

[0057] (3) The information processing and control device 4 controls the two electric push rods 9 to extend, applying loads in the X+ and X- directions to the robotic arm to be measured. The information processing and control device calculates the static stiffness data of the robotic arm to be measured in the X+ and X- directions according to the load values measured by the pressure sensors and the deformation amounts measured by the laser tracker;

[0058] (4) The information processing and control device controls the electric push rods 9 to retract and the electric lifting column 15 to rise, applying loads in the Z+ and Z- directions to the robotic arm to be measured. The information processing and control device calculates the static stiffness data of the robotic arm to be measured in the Z+ and Z- directions according to the load values measured by the pressure sensors and the deformation amounts measured by the laser tracker;

[0059] (5) The information processing and control device controls the electric lifting column 15 to descend, so that the rectangular pressing frame slides out of the first X-direction chute 11-1 through the first locking slider 13-1 and slides and locks to the Y-direction chute 11-2;

[0060] (6) Adjust the height of the tooling table 14 through the electric lifting column 15, and adjust the front and back position of the rectangular pressing frame through the Y-direction chute 11-2, so that the spherical surface of the spherical part 7 of the robotic arm to be measured is in radial contact with the test planes of the four pressure sensors, and then lock the first locking slider 13-1; The information processing and control device controls the two electric push rods 9 to extend, applying loads in the Y+ and Y- directions to the robotic arm to be measured. The information processing and control device calculates the static stiffness data of the robotic arm to be measured in the Y+ and Y- directions according to the load values measured by the pressure sensors and the deformation amounts measured by the laser tracker.

[0061] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also within the scope of protection of the present invention.

Claims

1. A mechanical arm static stiffness testing device, characterized in that: It includes a testing tool (2), a contact device, a laser tracker (3) and an information processing and control device (4); The test fixture (2) comprises a supporting device, a pressurizing device and a force collecting device; The supporting device is used to fix the mechanical arm to be measured, the laser tracker and the pressurizing device; The pressurizing device is used to provide loads in six directions: X+, X-, Y+, Y-, Z+, and Z-, so as to deform the robotic arm; The force acquisition device is installed on the pressurizing device to measure the load values ​​in the six directions of X+, X-, Y+, Y-, Z+, and Z- acting on the robotic arm; The contact device is installed at the end of the mechanical arm to be measured and is connected to the force acquisition device, so as to make the force direction of the mechanical arm consistent with the measurement direction of the force acquisition device; The laser tracker (3) is used to measure the deformation of the robot arm; The information processing and control device (4) is used to control the pressure device to apply load to the mechanical arm, and to process the measurement information of the force acquisition device and the laser tracker to obtain the static stiffness data of the mechanical arm.

2. A mechanical arm static stiffness testing device according to claim 1, characterized in that: The pressurizing device comprises a rectangular pressurizing frame, an electric push rod (9), a first X-direction slide groove (11-1), a Y-direction slide groove (11-2), a first locking slider (13-1), a tooling table (14) and an electric lifting column (15); the electric lifting column (15) is vertically fixed on the supporting device, and its telescopic end is connected to the tooling table (14); two first X-direction slide grooves (11-1) and two Y-direction slide grooves (11-2) are respectively fixed to four sides of the tooling table (14) in parallel along the X-axis direction and the Y-axis direction; the rectangular pressurizing frame is respectively connected to the first X-direction slide groove (11-1) or the Y-direction slide groove (11-2) by sliding and locking through the first locking slider (13-1); the telescopic ends of the two electric push rods (9) are relatively and symmetrically installed in the rectangular pressurizing frame, and the telescopic ends of the two electric push rods (9) and the upper and lower inner sides of the rectangular pressurizing frame are all connected to the force collection device.

3. A mechanical arm static stiffness testing device according to claim 2, characterized in that: The rectangular pressurizing frame comprises a fixed upper plate (6), a fixed bottom plate (10) and a fixed side plate (12); the fixed upper plate (6) and the fixed bottom plate (10) are connected via two fixed side plates (12) to form a rectangular pressurizing frame.

4. A mechanical arm static stiffness testing device according to claim 2, characterized in that: The force acquisition device comprises four pressure sensors, two of which are respectively fixedly connected to the telescopic ends of two electric push rods (9) of the pressurizing device, and the other two pressure sensors are respectively fixedly connected to the upper inner side surface and the lower inner side surface of the rectangular pressurizing frame of the pressurizing device.

5. A mechanical arm static stiffness testing device according to claim 4, characterized in that: The contact device comprises a spherical piece (7), one end of which is fixed on the mechanical arm, and the spherical surface of the other end is in radial contact with the test planes of four pressure sensors.

6. A mechanical arm static stiffness testing device according to claim 5, characterized in that: The spherical part (7) comprises a spherical part and a round rod part, one end of the round rod part is axially fixed on the end of the mechanical arm to be tested, and the other end is fixedly connected to the spherical part.

7. The mechanical arm static stiffness testing device according to claim 1, characterized in that: The supporting device comprises a base plate (16), two second X-direction slide grooves (11-3) fixed on the base plate (16) along the X-axis direction, a second locking slider (13-2) and a fixed column (5); the bottom of the fixed column (5) is slidably and lockingly connected with the two second X-direction slide grooves (11-3) via the second locking slider (13-2), and the top of the fixed column (5) is used to fix the mechanical arm to be tested.

8. A method for testing static stiffness of a robotic arm, characterized in that: Using the mechanical arm static stiffness testing device described in claim 5 specifically comprises the following steps: (1) fixing the mechanical arm to be tested on a test fixture, placing a laser tracker on one side of the test fixture, fixing a spherical piece (7) on the mechanical arm to be tested, and fixing a target ball of the laser tracker on the spherical piece (7); (2) the rectangular pressurizing frame is connected to the first X-direction slide groove (11-1) by sliding and locking through the first locking slider (13-1); the height of the workbench (14) is adjusted through the electric lifting column (15), and the front and rear positions of the rectangular pressurizing frame are adjusted through the first X-direction slide groove (11-1), so that the spherical surface of the spherical part (7) of the mechanical arm to be tested is in radial contact with the test planes of the four pressure sensors, and then the first locking slider (13-1) is locked; the information processing and control device controls the two electric push rods (9) to extend, and applies loads in the X+ and X- directions to the mechanical arm to be tested. The information processing and control device calculates the static stiffness data of the mechanical arm to be tested in the X+ and X- directions according to the load value measured by the pressure sensor and the deformation measured by the laser tracker; (3) The information processing and control device controls the electric push rod (9) to retract and the electric lifting column (15) to rise, and applies loads in the Z+ and Z- directions to the mechanical arm to be tested. The information processing and control device calculates the static stiffness data of the mechanical arm to be tested in the Z+ and Z- directions according to the load value measured by the pressure sensor and the deformation measured by the laser tracker; (4) The information processing and control device controls the electric lifting column (15) to descend, so that the rectangular pressurizing frame slides out of the first X-direction slide groove (11-1) through the first locking slide block (13-1) and is slidably and lockedly connected with the Y-direction slide groove (11-2); the height of the workbench (14) is adjusted through the electric lifting column (15), and the front and rear positions of the rectangular pressurizing frame are adjusted through the Y-direction slide groove (11-2), so that the spherical surface of the spherical part (7) of the mechanical arm to be tested is in radial contact with the test planes of the four pressure sensors, and then the first locking slide block (13-1) is locked; the information processing and control device controls the two electric push rods (9) to extend, and applies loads in the Y+ and Y- directions to the mechanical arm to be tested. The information processing and control device calculates the static stiffness data of the mechanical arm to be tested in the Y+ and Y- directions according to the load value measured by the pressure sensor and the deformation measured by the laser tracker.

9. A method for testing static stiffness of a mechanical arm according to claim 8, characterized in that: The supporting device comprises a base plate (16), two second X-direction slide grooves (11-3) fixed on the base plate (16) along the X-axis direction, a second locking slider (13-2) and a fixed column (5); the bottom of the fixed column (5) is slidably and lockingly connected with the two second X-direction slide grooves (11-3) via the second locking slider (13-2), and the top of the fixed column (5) is used to fix the mechanical arm to be tested; In steps (2), (3) and (4), the distance between the robot arm to be tested and the pressurizing device is preliminarily adjusted by adjusting the position of the fixed column (5) on the second X-direction slide groove (11-3), and then the front and rear positions of the rectangular pressurizing frame are adjusted through the Y-direction slide groove (11-2) or the first X-direction slide groove (11-1).

10. A method for testing static stiffness of a mechanical arm according to claim 8, characterized in that: The information processing and control device calculates the static stiffness data according to the following formula: Ks=(F1-F2) / (D1-D2) in, Ks: static stiffness, kN / mm; F1: minimum load applied to the robot arm to be tested, kN; F2: Maximum load applied to the robot arm to be tested, kN; D1: displacement of the robot arm under test when the load is applied to F1, mm; D2: Displacement of the robot arm under test when the load is applied to F2, mm.

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