Multi-degree-of-freedom robotic arm low-stress assembly system and method based on multi-point support force feedback

Abstract

The invention discloses a low-stress assembly method for a multi-degree-of-freedom manipulator based on multi-point support force feedback, which belongs to the field of aerospace technology and includes an air-floating support device, a force monitoring system, an air-floating platform and an air distribution device; the air-floating support device is placed on the air-floating platform, and the air distribution device is used to supply air to the plane air foot of each air-floating support device so that the air-floating support device floats; the air-floating support device is used to simulate the zero-gravity state of the multi-degree-of-freedom space manipulator on the ground, reduce or eliminate the assembly stress of the product, and reduce the influence of gravity on the function and performance of the space manipulator product; the force monitoring system includes a plurality of force sensors arranged on the air-floating support device, which are used to monitor the stress state of each movable part before and after assembly, and realize the three-dimensional full physical movement of the multi-degree-of-freedom manipulator based on the air-floating platform.

Description

Technical Field

[0001] The invention relates to a low-stress assembly method for a multi-freedom mechanical arm based on multi-point support force feedback, and belongs to the field of aerospace technology. Background Art

[0002] The space robotic arm is in a microgravity state in orbit. The product is not affected by gravity, there is no assembly stress between the moving parts, and it has high life and high reliability requirements. During the ground assembly and testing stage, due to the influence of gravity, the product is subject to additional assembly stress, which causes the force sensor data of the moving parts themselves to be distorted and the performance test results to be distorted. In severe cases, it may lead to invalid test results or even product damage. Therefore, a low-stress assembly method is required during the ground assembly and testing stage to offset the impact of gravity on product functions and performance, reduce the assembly stress of the product, and ensure the accuracy of product test data during assembly and movement. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a low-stress assembly method for a multi-degree-of-freedom robotic arm based on multi-point support force feedback, for the 3+1+3 configuration of the robotic arm, the three pitch joint movements are designed to be planar movements, the shoulder / wrist yaw and slew joints utilize a support + suspension method, and the overall air floating support method is adopted to independently support each movable component, and the motion trajectory of the support device is maintained, the motion correlation between products is decoupled, and force sensor measurement is used to achieve the purpose of accurately adjusting the related forces between products, thereby achieving the low assembly stress goal of the space robotic arm and supporting the three-dimensional physical movement of the space robotic arm on the air floating platform.

[0004] The technical solution of the present invention is: an air-floating support system for low-stress assembly of a multi-degree-of-freedom robotic arm, comprising an air-floating support device, a force monitoring system, an air-floating platform and an air distribution device;

[0005] The air-floating support device is placed on the air-floating platform, and the air distribution device supplies air to each plane of the air-floating support device to make the air-floating support device float; the air-floating support device is used to simulate the zero-gravity state of the multi-degree-of-freedom space robot arm on the ground, reduce or eliminate the assembly stress of the product, and reduce the influence of gravity on the function and performance of the space robot arm product;

[0006] The force monitoring system includes a plurality of force sensors arranged on the air-floating support device, which are used to monitor the force state of each movable part before and after assembly.

[0007] Furthermore, the air floating support device comprises:

[0008] Shoulder pitch brackets for low-stress mounting of the shoulder end and shoulder swivel joint; and

[0009] Shoulder translation mounts for low-stress mounting of shoulder yaw and shoulder pitch joints; and

[0010] Two first arm brackets are provided, used for supporting and fixing the first arm of the space manipulator; and

[0011] Elbow translation bracket, used for low-stress assembly of the space robot elbow pitch joint and the space robot center control assembly; and

[0012] A second arm bracket, used for supporting and fixing the second arm of the space manipulator; and

[0013] The wrist bracket is used for low-stress assembly of the pitch joint of the space manipulator wrist, the yaw joint of the space manipulator wrist, the extension of the space manipulator wrist joint, the swivel joint assembly of the space manipulator wrist, and the end effector of the space manipulator wrist.

[0014] Furthermore, the shoulder pitch support comprises:

[0015] The shoulder pitch air-floating support trolley mechanism provides an operating platform for assembly, including four shoulder pitch support plane air feet, a trolley, rollers, bearing seats, roller seats, and bearings; the shoulder pitch support plane air feet are connected to the bottom of the trolley through connecting screws to provide air buoyancy for the trolley; a support frame is provided on each side of the trolley, a bearing is fixed on the top of one support frame, a roller seat is fixed on the top of the other support frame, two bearing seats are provided on the roller seats, and the roller ring on the trolley is tangent to the two rollers; the shoulder swivel joint posture adjustment mechanism and four height adjustment mechanisms are provided on the shipboard; and

[0016] A ship plate is located above the frame vehicle, one side of the ship plate is rotatably connected to the bearing through the pitch axis, and the other side of the ship plate is fixedly connected to the roller ring; and

[0017] The small roller ring at the end of the shoulder and the large roller ring at the end of the shoulder are connected to the end effector of the shoulder of the space robot arm, and there is a preset range of coaxiality between the three, so that the end effector of the shoulder of the space robot arm can rotate freely around its own rotation axis after being installed on the end posture adjustment mechanism.

[0018] Further, the shoulder translation support includes four shoulder translation support plane air feet, a shoulder translation support body, a fixing plate, three double-threaded adjustment rods, an adjustment plate, four shoulder yaw joint attitude fine-tuning mechanisms, a shoulder yaw joint support frame, an upper hanging plate, a bearing, a rotating hanging plate, and four shoulder pitch joint attitude fine-tuning mechanisms;

[0019] The plane air foot of the shoulder translation support is connected to the bottom of the shoulder translation frame body through a connecting screw, which is used to provide air buoyancy for the shoulder translation frame body; the fixed plate is fixed on the shoulder translation frame body, and the height and attitude of the adjustment plate are roughly adjusted by three double-threaded adjustment rods; four shoulder yaw joint attitude fine-tuning mechanisms are installed on the adjustment plate, and a force sensor is connected in series in each shoulder yaw joint attitude fine-tuning mechanism; the shoulder yaw joint support frame is installed on the frame body, and an upper hanging plate is assembled on it, and the rotating hanging plate is connected to the upper hanging plate through a bearing.

[0020] Further, the elbow translation support includes four elbow translation support plane air feet, an elbow translation support body, four elbow pitch joint posture adjustment mechanisms, three double-threaded adjustment rods, a screw support ring, an air floating support plate, an air floating plate, three central control assembly posture adjustment mechanisms, a first central control assembly mounting bracket, and a second central control assembly mounting bracket;

[0021] The plane air foot of the elbow translation support is connected to the bottom of the elbow translation support body through a connecting screw, and is used to provide air buoyancy for the elbow translation support body;

[0022] A force sensor is connected in series in each elbow pitch joint posture adjustment mechanism, for a total of four;

[0023] The air-floating support plate is installed on the elbow translation support body through three double-threaded adjustment rods and a screw support ring, serving as a floating base of the air-floating plate; after the first central control assembly mounting bracket, the second central control assembly mounting bracket and the space manipulator central control assembly are installed, they are fixed to the air-floating plate through each central control assembly posture adjustment mechanism, and each central control assembly posture adjustment mechanism is connected in series with a force sensor, for a total of three; ventilation is formed between the air-floating plate and the air-floating support plate to form an air film, so that the air-floating plate floats, thereby offsetting gravity and reducing motion friction;

[0024] The elbow translation bracket is used for low-stress assembly of the elbow pitch joint of the space manipulator and the central control assembly of the space manipulator.

[0025] Further, the wrist support includes eight wrist support plane gas feet, a wrist support body, four wrist pitch joint posture adjustment mechanisms, a wrist yaw joint suspension, a column support, a fixed column, a rotary column, a sliding sleeve, a fixed pulley, a wire rope, a movable pulley, a U-shaped suspension, an upper crossbeam, an upper crossbeam counterweight, a wrist rotary joint similar mechanism suspension, and a wrist end effector similar suspension;

[0026] The wrist support body is the main part of the wrist support, which is used for integration, installation, connection, support and rigidity maintenance of various components;

[0027] A force sensor is connected in series in each wrist pitch joint posture adjustment mechanism;

[0028] The wrist yaw joint suspension includes a pull rod and a slewing bearing; a force sensor is connected in series between the pull rod and the slewing bearing;

[0029] The column bracket is installed above the wrist bracket body;

[0030] The fixed column is fixed on the column bracket, and the swivel column is installed in coordination with the fixed column and can rotate freely in the fixed column;

[0031] The sliding sleeve adapts to the position deviation of the U-shaped suspension and the upper beam during assembly, and slides freely on the horizontal axis of the rotary column;

[0032] Pulleys for wire rope routing are installed in the column bracket, fixed column and slewing column, wherein the fixed pulley is installed at the bottom of the sliding sleeve, the upper end of the U-shaped hanging is connected to the movable pulley, and the lower end is connected to the upper crossbeam; the wire rope passes through the fixed pulley, movable pulley and the pulleys in the slewing column, fixed column and column bracket in turn, and is connected to the counterweight so that the counterweight offsets the gravity of the wrist slewing assembly;

[0033] The upper beam counterweight is installed on the upper beam, and the wrist rotation assembly is assisted to achieve balance in any situation by adjusting the mass and position of the counterweight;

[0034] The wrist swivel joint similar mechanism suspension is connected to the space manipulator wrist joint extension and the space manipulator wrist swivel joint assembly to achieve static balance of the assembly. By adjusting the wrist swivel joint similar mechanism counterweight and the wrist swivel joint counterweight, the center of mass of the assembly is adjusted to the axis of the suspension rod on the wrist swivel joint to achieve random balance.

[0035] The wrist end effector similar suspension is connected to the wrist end effector of the space manipulator, and is used to achieve the static balance of the wrist end effector of the space manipulator. By adjusting the counterweight of the wrist end effector similar mechanism and the wrist end effector counterweight, the center of mass of the wrist end effector of the space manipulator is adjusted to the axis of the suspension rod on the wrist end effector, so as to achieve the balance in any situation.

[0036] The upper crossbeam, the wrist swivel joint-like mechanism suspension, and the wrist end effector-like suspension form a large parallelogram-like mechanism. By adjusting the counterweight position of the upper crossbeam, as well as the installation positions of the wrist swivel joint-like mechanism suspension and the wrist end effector-like suspension on the upper crossbeam, the center of mass of the large assembly of the space manipulator wrist joint extension, the space manipulator wrist swivel joint, and the wrist end effector is adjusted to the U-shaped suspension axis to achieve the random balance of the large assembly.

[0037] Further, the force monitoring system includes at least thirty force sensors; wherein

[0038] The first group of force sensors includes at least four force sensors for monitoring the force of the end effector of the shoulder of the space robot arm;

[0039] The second group of force sensors includes at least four force sensors, which are used to monitor the forces of the shoulder swivel joint and the shoulder joint extension assembly of the space robot arm;

[0040] The third group of force sensors includes at least four force sensors for monitoring the force of the shoulder yaw joint of the space manipulator;

[0041] The fourth group of force sensors includes at least four force sensors for monitoring the forces of the pitch joints of the shoulders of the space manipulator;

[0042] The fifth group of force sensors includes at least four force sensors for monitoring the forces of the pitch joints of the elbows of the space manipulator;

[0043] The sixth group of force sensors includes at least three force sensors for monitoring the forces on the central control assembly of the space manipulator;

[0044] The seventh group of force sensors includes at least four force sensors for monitoring the forces of the pitch joints of the wrist of the space manipulator;

[0045] The eighth set of force sensors is used to monitor the force on the yaw joint of the space manipulator wrist;

[0046] The ninth group of force sensors is used to monitor the force of the space manipulator wrist joint extension and the space manipulator wrist rotation joint assembly;

[0047] The tenth group of force sensors is used to monitor the forces on the space manipulator wrist joint extension, the space manipulator wrist swivel joint, and the space manipulator wrist end effector assembly.

[0048] Furthermore, the multi-degree-of-freedom spatial robot is divided into degrees of freedom according to the configuration and layout status, and the air floating support device is divided into four components: shoulder pitch motion component, shoulder translation motion component, elbow translation motion component, and wrist motion component. The shoulder, elbow, and wrist are selected as needed for grouping and fixing to realize the movement of each motion joint of the spatial multi-degree-of-freedom robot.

[0049] Furthermore, the air-floating support device is used for low-stress assembly between each unit during the assembly phase, while taking into account the motion test requirements of the robotic arm, to achieve the morphological transformation of the robotic arm's assembly configuration, test configuration, and folded configuration, as well as the low-stress state of each moving joint during three-dimensional movement.

[0050] A multi-degree-of-freedom robotic arm low-stress assembly method based on multi-point support force feedback includes:

[0051] Step 1: Level the shoulder pitch air-floating support frame mechanism; install the shipboard on the shoulder pitch air-floating support frame mechanism, one side of the shipboard is rotatably connected to the bearing through the pitch axis, and the other side of the shipboard is fixedly connected to the roller ring; by adjusting the positions of the two rollers and the installation position of the roller ring on the shipboard, ensure the parallelism between the axis of the roller ring and the plane of the air-floating platform;

[0052] Step 2: Install the space manipulator shoulder swivel joint and the space manipulator shoulder joint extension assembly on the shoulder swivel joint posture adjustment mechanism and connect it to the shipboard. Adjust the axis of the space manipulator shoulder joint extension through four height adjustment mechanisms to ensure that the axis of the space manipulator joint extension is coaxial with the roller ring; record the force of the second group of force sensors;

[0053] Step 3: Connect the end effector of the shoulder of the space robot arm with the small roller ring at the end of the shoulder and the large roller ring at the end of the shoulder, measure and adjust the coaxiality of the small roller ring at the end of the shoulder, the large roller ring at the end of the shoulder and the end effector of the shoulder of the space robot arm, and weigh and calculate and adjust the center of mass of the assembly to ensure that the center of mass of the assembly is located on the axis of the end effector of the shoulder of the space robot arm;

[0054] Step 4: Install the end effector of the shoulder of the space robot arm on the end posture adjustment mechanism, measure and adjust the coaxiality of the end effector of the shoulder of the space robot arm and the output shaft of the shoulder rotary joint of the space robot arm, and record the force of the first group of force sensors;

[0055] Step 5: docking the space manipulator shoulder end effector and the space manipulator shoulder swivel joint on the shipboard;

[0056] Step 6: Adjust the counterweight on the shipboard so that the center of mass of the equipment and tooling assembly on the shipboard is located on the axis of the space robot arm joint extension to achieve the random balance of the assembly;

[0057] Step 7: Install the shoulder yaw joint of the space manipulator on the shoulder translation bracket, lower the shoulder yaw joint of the space manipulator to the lowest point through three double-threaded adjustment rods, and adjust the posture of the shoulder yaw joint of the space manipulator through four shoulder yaw joint posture fine-tuning mechanisms to ensure the parallelism of the output shaft axis of the shoulder yaw joint of the space manipulator and the ground, and the verticality of the fixed shaft axis and the ground;

[0058] Step 8: Connect the shoulder pitch joint of the space manipulator to the four shoulder pitch joint attitude fine-tuning mechanisms, measure and adjust the parallelism between the axis of the shoulder pitch joint fixer of the space manipulator and the ground, and the verticality between the axis of the output shaft and the ground; record the force of the fourth group of force sensors;

[0059] Step 9: Raise the yaw joint of the shoulder of the space manipulator through three double-threaded adjustment rods and dock it with the pitch joint of the shoulder of the space manipulator; adjust the posture of the yaw joint of the shoulder of the space manipulator through four fine-tuning mechanisms of the yaw joint, control the force changes of the third group of force sensors and the fourth group of force sensors within the preset range, and ensure the height difference between the yaw joint of the shoulder of the space manipulator and the axis of the shoulder joint extension of the space manipulator; re-measure the coaxiality of the pitch joint of the shoulder of the space manipulator and the yaw joint of the shoulder of the space manipulator, and the height of the axis to the ground;

[0060] Step 10: dock the yaw joint of the space manipulator shoulder with the space manipulator shoulder joint extension; control the force changes of the first to fourth groups of force sensors within a preset range by adjusting the terminal posture adjustment mechanism, the shoulder swivel joint posture adjustment mechanism, the shoulder yaw joint posture fine-tuning mechanism, and the shoulder pitch joint posture fine-tuning mechanism; re-measure the coaxiality and axis height between the single machines;

[0061] Step 11: Use the ground inspection equipment to carry out the dynamic balance test of the space manipulator shoulder swivel joint, the dynamic balance test of the space manipulator shoulder yaw joint, and the dynamic balance test of the space manipulator shoulder pitch joint in sequence; confirm that the force changes of the first to fourth groups of force sensors are controlled within the preset range; otherwise, perform iterative measurement and adjustment;

[0062] Step 12: Fix the end effector of the space robot shoulder to the assembly support vehicle as the fixed end of the space robot assembly, and start the subsequent assembly work;

[0063] Step 13: The first arm of the space robot is installed on two first arm brackets, and the axis height of the first arm of the space robot and the coaxiality with the pitch joint of the shoulder of the space robot are adjusted by four threaded rods;

[0064] Step 14: Install the elbow pitch joint of the space manipulator on the elbow translation bracket, and adjust the posture of the elbow pitch joint of the space manipulator through four elbow pitch joint posture adjustment mechanisms to ensure the parallelism of the fixed axis of the elbow pitch joint of the space manipulator and the ground, the verticality of the output axis and the ground, and the coaxiality with the first arm of the space manipulator; record the force of the fifth group of force sensors; first raise the air floating support plate to the highest point through three double-threaded adjustment rods;

[0065] Step 15: Assemble the space robot arm central control assembly, the first central control assembly mounting bracket, the second central control assembly mounting bracket, the three central control assembly posture adjustment mechanisms, and the air floating plate, and adjust the verticality of the axis of the space robot arm central control assembly and the air floating plane of the air floating plate through the central control assembly posture adjustment mechanism; record the force of the sixth group of force sensors;

[0066] Step 16: dock the large assembly formed by the space robot arm central control assembly and the mounting bracket with the air floating support plate, and at the same time lower the large assembly through three double-threaded adjustment rods to dock with the space robot arm elbow pitch joint, and control the force changes of the fifth group of force sensors and the sixth group of force sensors within the preset range; measure the coaxiality and axis height of the space robot arm elbow pitch joint and the space robot arm central control assembly;

[0067] Step 17: Assemble and dock the first arm of the space manipulator with the shoulder pitch joint of the space manipulator and the elbow pitch joint of the space manipulator to form a front half arm; control the force changes of the first to sixth groups of force sensors within a preset range; measure the axis size of the front half arm and the coaxiality between the single machines;

[0068] Step 18: Install the second arm of the space robot arm on the second arm bracket, and adjust the axis height of the second arm of the space robot arm and the coaxiality with the central control assembly of the space robot arm through four threaded rods;

[0069] Step 19: Install the pitch joint of the wrist of the space manipulator on the wrist bracket, and adjust the posture of the pitch joint of the wrist of the space manipulator through four wrist pitch joint posture adjustment mechanisms to ensure the parallelism of the fixed axis of the wrist pitch joint of the space manipulator and the ground, the verticality of the output axis and the ground, and the coaxiality with the second arm of the space manipulator; record the force of the seventh group of force sensors;

[0070] Step 20: Connect the wrist yaw joint of the space manipulator and the wrist yaw joint suspension, adjust the mass center of the assembly to the axis of the fixed axis of the wrist yaw joint of the space manipulator, and achieve the dynamic balance state of the wrist yaw joint of the space manipulator; adjust the double-threaded adjustment rod to adjust the wrist yaw joint suspension to the shortest state;

[0071] Step 21: Connect the yaw joint of the wrist of the space manipulator and the wrist yaw joint suspension assembly to the wrist bracket, and make the fixed axis of the yaw joint of the wrist of the space manipulator coaxial with the output axis of the pitch joint of the wrist of the space manipulator by adjusting the transverse adjustment block and the longitudinal adjustment block; record the force of the eighth group of force sensors;

[0072] Step 22: Adjust the double-threaded adjustment rod to dock the yaw joint of the wrist of the space manipulator with the pitch joint of the wrist of the space manipulator, and control the force changes of the seventh group of force sensors and the eighth group of force sensors within a preset range through fine-tuning of the four wrist pitch joint posture adjustment mechanisms; measure the axis height of the fixed axis of the pitch joint of the wrist of the space manipulator and its coaxiality with the second arm, the axis height of the output axis of the yaw joint of the wrist of the space manipulator, and the coaxiality of the fixed axis and the output axis of the pitch joint of the wrist of the space manipulator;

[0073] Step 23: Use ground inspection equipment to perform motion test on the pitch joint of the wrist of the space manipulator to confirm that within the allowable angle range, the force changes of the seventh group of force sensors and the eighth group of force sensors are controlled within the preset range; otherwise, continue to adjust according to step 22 until the requirements are met;

[0074] Step 24: docking and weighing the wrist joint extension of the space manipulator and the wrist swivel joint of the space manipulator to form a first assembly; assembling the first assembly and the wrist swivel joint similar mechanism to form a second assembly, forming a parallelogram similar mechanism, and adjusting the counterweight of the wrist swivel joint similar mechanism and the wrist swivel joint counterweight to adjust the center of mass of the middle assembly to the axis of the suspension rod on the wrist swivel joint, and achieve random balance; recording the force of the ninth group of force sensors;

[0075] Step 25: Assemble the space manipulator wrist end effector and the wrist end effector similar suspension to form a third assembly, forming a parallelogram similar mechanism, and adjust the center of mass of the space manipulator wrist end effector to the axis of the suspension rod on the wrist end effector by adjusting the counterweight of the wrist end effector similar mechanism and the wrist end effector counterweight to achieve random balance;

[0076] Step 26: Install the second assembly and the third assembly with the upper beam to form a fourth assembly, forming a parallelogram-like mechanism, and adjust the center of mass of the fourth assembly to the U-shaped hanging axis by adjusting the counterweight position of the upper beam, the wrist swivel joint-like mechanism hanging, and the installation position of the wrist end effector hanging on the upper beam, so as to achieve the random balance of the fourth assembly around the U-shaped hanging axis; record the force of the tenth group of force sensors;

[0077] Step 27: Use ground inspection equipment to perform motion test on the wrist swivel joint of the space manipulator to confirm that within the allowable angle range, the force change of the ninth group of force sensors is controlled within the preset range; otherwise, continue to adjust according to steps 25 and 26 until the requirements are met;

[0078] Step 28: Confirm the routing of the wire rope; prepare the counterweight, and take half of the force of the tenth group of force sensors before peeling as the standard value for the counterweight preparation; connect the fourth assembly formed in step 26 with the wire rope on the wrist bracket to form a complete wrist assembly, and adaptively adjust the counterweight so that the force changes of the seventh to tenth groups of force sensors are controlled within the preset range; measure the axis height and coaxiality of each single machine;

[0079] Step 29: Use ground inspection equipment to perform motion tests on the pitch joint, yaw joint, and swivel joint of the space manipulator wrist to confirm that within the allowable angle range, the force changes of the seventh to tenth groups of force sensors are controlled within the preset range; otherwise, continue to adjust according to steps 22 to 26 until the requirements are met;

[0080] Step 30: dock the second arm of the space manipulator with the central control assembly of the space manipulator and the pitch joint of the wrist of the space manipulator to form a complete arm; monitor the state of the force sensor and control the force changes of all force sensors within a preset range; measure the axis size of the manipulator, the coaxiality between the single machines, and all DH parameters;

[0081] Step 31: Perform single joint motion tests on seven joints of the space robot arm to confirm the low-stress assembly state of the robot arm.

[0082] The advantages of the present invention compared with the prior art are:

[0083] 1) The present invention proposes an air-floating support system, which is composed of an air-floating support device, a force monitoring system, an air-floating platform and an air distribution device; it realizes the three-dimensional full physical movement of a multi-degree-of-freedom manipulator based on the air-floating platform;

[0084] 2) The present invention provides an air-floating support device according to the distribution of the degrees of freedom of the space manipulator. The air-floating support device is divided into four components by dividing the degrees of freedom of motion: a shoulder pitch motion component, a shoulder translation motion component, an elbow translation motion component, and a wrist motion component. Through the reasonable design of the air-floating support device, a large range of motion of each motion joint of the space multi-degree-of-freedom manipulator is supported, and the folding state of the manipulator can be realized;

[0085] 3) The present invention proposes an assembly method based on multi-point support force feedback. By designing force sensors for movable parts, the force state of each movable part can be monitored. According to the change of the support force measured by the force sensor before and after docking, the interaction force between the assembly interfaces can be determined;

[0086] 4) The present invention decouples the interrelationships of various motion joints by decomposing the assembly process, realizes the functional and motion decomposition of small parts, and finally the complete docking of the whole arm, and realizes the independent segmentation of multi-degree-of-freedom robot arm motion;

[0087] 5) The present invention provides a low-stress assembly method for a spatial multi-degree-of-freedom robotic arm. In the assembly stage of individual moving parts, precision control is mainly used, supplemented by force control. In the docking assembly stage between moving parts, the assembly accuracy is first adjusted to meet the coaxiality and other deviations before docking. The docking process is mainly force control, supplemented by precision control. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 It is a schematic diagram of the composition of the air floating support device and the space manipulator of the present invention;

[0089] Figure 2 is a schematic diagram of the shoulder pitch support;

[0090] Figure 3 It is a schematic diagram of the shoulder pitch air-floating support vehicle frame mechanism;

[0091] Figure 4 It is a schematic diagram of the ship's plank;

[0092] Figure 5 is a schematic diagram of the shoulder translation support;

[0093] Figure 6 is a schematic diagram of the primary boom bracket;

[0094] Figure 7 is a schematic diagram of the elbow translation support;

[0095] Figure 8 is a schematic diagram of the second boom bracket;

[0096] Fig. 9 is a schematic diagram of a wrist brace;

[0097] Fig.10 It is a schematic diagram of the wrist yaw joint suspension;

[0098] Fig.11 It is a schematic diagram of the similar mechanism hanging of the wrist swivel joint;

[0099] Fig.12 is a schematic diagram of a similar hanging of the wrist end effector;

[0100] Fig.13 It is a schematic diagram of the wrist support wire rope routing;

[0101] Fig.14 It is a schematic diagram of the distribution of force sensors of the air-floating support device;

[0102] Fig.15 This is a schematic diagram of the principle of a similar mechanism. DETAILED DESCRIPTION

[0103] In order to better understand the above technical scheme, the technical scheme of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical scheme of the present application, rather than limitations on the technical scheme of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0104] The following is a further detailed description of the multi-degree-of-freedom mechanical arm low-stress assembly method based on multi-point support force feedback provided by the embodiment of the present application in conjunction with the accompanying drawings of the specification. The specific implementation method may include (such as Figures 1 to 15 As shown): The assembly method is implemented based on an air floating support system, including an air floating support device, a force monitoring system, an air floating platform and an air distribution device; the air floating support device includes a shoulder pitch support, a shoulder translation support, an elbow translation support, a wrist support and an arm support.

[0105] The assembly method comprises: an air foot is arranged at the bottom of each air-floating support device and placed on an air-floating platform; each movable part of the space robot arm is sequentially installed on each air-floating support device, a force sensor is connected in series with the connection part of each bracket with the robot arm product, and the force sensor is used to monitor the stress state of the connection part; after the accuracy of the axis deviation and coaxiality of adjacent products meets the requirements, assembly and docking are carried out, and air is supplied to the air foot of each bracket through the air distribution device to realize the low-friction movement of each bracket on the air-floating platform; the interaction force of the brackets of adjacent products is judged according to the force change before and after assembly, and the position and posture of the assembled products are adjusted through the assembly adjustment link until the stress state of the adjacent products meets the error allowance requirements.

[0106] In the solution provided in the embodiment of the present application, the assembly method is implemented based on an air floating support system, including an air floating support device, a force monitoring system, an air floating platform and an air distribution device; the air floating support device includes a shoulder pitch support 1, a shoulder translation support 2, a first arm support 3, an elbow translation support 4, a second arm support 5, and a wrist support 6; the space robot arm is composed of a shoulder end effector 7, a shoulder swivel joint 8, a shoulder joint extension 9, a shoulder yaw joint 10, a shoulder pitch joint 11, a first arm 12, an elbow pitch joint 13, a central control assembly 14, a second arm 15, a wrist pitch joint 16, a wrist yaw joint 17, a wrist joint extension 18, a wrist swivel joint 19, and a wrist end effector 20.

[0107] The shoulder pitch bracket 1 consists of a shoulder pitch air-floating support frame mechanism 21, a shoulder swivel joint position adjustment mechanism 22, four height adjustment mechanisms 23, a shipboard 24, a small roller ring 25 at the shoulder end, a large roller ring 26 at the shoulder end, and an end position adjustment mechanism 27, which is used for low-stress assembly of the shoulder end and the shoulder swivel joint.

[0108] The low-stress assembly is achieved by designing and implementing means to reduce and eliminate the assembly stress between products. It can be characterized by the changes in the force sensors supporting the components before and after the components are assembled and docked, so as to simulate the weightless and non-interactive state between the components of the space robot arm in orbit during the ground assembly and testing phase.

[0109] The shoulder pitch air-floating support frame mechanism 21 includes four plane air feet 28, a frame 29, rollers 30, a bearing seat 31, a roller seat 32, and a bearing 33. The plane air feet 28 are connected to the bottom of the frame 29 through a connecting screw 34 to provide air buoyancy for the frame 29. A support frame is provided on each side of the frame 29, a bearing 33 is fixed on the top of one support frame, and a roller seat 32 is fixed on the top of the other support frame. Two bearing seats 31 are provided on the roller seat 32, and a roller ring 35 on the frame 29 is tangent to the two rollers 30.

[0110] The shipboard 24 is located above the frame vehicle 29, one side of the shipboard 24 is rotatably connected to the bearing 33 via the pitch axis 36, and the other side of the shipboard 24 is fixedly connected to the roller ring 35;

[0111] The shoulder swivel joint posture adjustment mechanism 22 and four height adjustment mechanisms 23 are arranged on the shipboard 24;

[0112] The shoulder pitch air-floating support frame mechanism 21 provides a basic operating platform for assembly, and the shoulder swivel joint posture adjustment mechanism 22 and four height adjustment mechanisms 23. Four plane air feet 28 are installed on its bottom surface. Before assembly, the entire air-floating support frame mechanism 21 needs to be leveled; a force sensor is connected in series in each height adjustment mechanism 23, a total of four; two force sensors are arranged in each end posture adjustment mechanism 27, a total of four.

[0113] The shoulder translation support 2 is composed of four planar air feet 28, a shoulder translation support body 38, a fixing plate 39, three double-threaded adjustment rods 40, an adjustment plate 41, four shoulder yaw joint attitude fine-tuning mechanisms 42, a shoulder yaw joint support frame 43, an upper hanging plate 44, a bearing 45, a rotating hanging plate 46, and four shoulder pitch joint attitude fine-tuning mechanisms 47; it is used to achieve low-stress assembly of the shoulder yaw joint and the shoulder pitch joint.

[0114] The plane air foot 28 is connected to the bottom of the shoulder translation carriage body 38 through the connecting screw 34, which is used to provide air buoyancy for the shoulder translation carriage body 38; the fixing plate 39 is fixed on the shoulder translation carriage body 38, and the height and posture of the adjustment plate 41 are roughly adjusted through three double-threaded adjustment rods 40; four shoulder yaw joint posture fine-tuning mechanisms 42 are installed on the adjustment plate 41, and each shoulder yaw joint posture fine-tuning mechanism 42 is connected in series with a force sensor, a total of four; the shoulder yaw joint support frame 43 is installed on the carriage body 38, and an upper hanging plate 44 is assembled thereon, and a rotating hanging plate 46 is connected to the upper hanging plate through a bearing 45;

[0115] The first arm support 3 is composed of four plane gas feet 28, a first arm support body 48, four threaded rods 49, a first arm adjustment plate 50, and two support blocks 51; the two first arm supports 3 are used to realize the support and fixation of the first arm 12;

[0116] The elbow translation bracket 4 is composed of four plane air feet 28, an elbow translation bracket body 52, four elbow pitch joint posture adjustment mechanisms 53, three double-threaded adjustment rods 54, a screw support ring 55, an air floating support plate 56, an air floating plate 57, three central control assembly posture adjustment mechanisms 58, a first central control assembly mounting bracket 59, and a first central control assembly mounting bracket 60; a force sensor is connected in series in each elbow pitch joint posture adjustment mechanism 53, for a total of four; a force sensor is connected in series in each central control assembly posture adjustment mechanism 58, for a total of three; the elbow translation bracket 4 is used to achieve low-stress assembly of the elbow pitch joint 13 and the central control assembly 14;

[0117] The second arm support 5 is composed of four plane gas feet 28, a second arm support body 61, four threaded rods 62, a second arm adjustment plate 63, and four support blocks 64; the second arm support 5 is used to support and fix the second arm 15;

[0118] The wrist support 6 is composed of 8 plane air feet 28, a wrist support body 65, four wrist pitch joint posture adjustment mechanisms 66, a wrist yaw joint suspension 67, a column support 68, a fixed column 69, a swivel column 70, a sleeve 71, a fixed pulley 72, a wire rope 73, a movable pulley 74, a U-shaped suspension 75, an upper crossbeam 76, an upper crossbeam counterweight 77, a wrist swivel joint similar mechanism suspension 78, and a wrist end effector similar suspension 79; a force sensor is connected in series in each wrist pitch joint posture adjustment mechanism 66, for a total of four; the wrist support is used to realize low-stress assembly of the wrist pitch joint 16, the wrist yaw joint 17, the wrist joint extension 18 and the wrist swivel joint 19 combination, and the wrist end effector 20;

[0119] The wrist yaw joint suspension 67 is composed of a transverse adjustment block 80, a longitudinal adjustment block 81, a pull rod 82, a slewing bearing 83, a double-threaded adjustment rod 84, a screw sleeve 85, a yaw joint suspension plate slewing shaft 86, a yaw joint suspension plate 87, a wrist yaw joint adapter block 88, and a wrist yaw joint adjustment counterweight 89; a force sensor is connected in series between the pull rod 82 and the slewing bearing 83;

[0120] The wrist swivel joint similar mechanism suspension 78 is composed of an upper lifting ear 90, a double-threaded adjustment rod 91, a wrist swivel joint upper suspension rod 92, a wrist swivel joint similar triangular plate 93, an upper suspension rod rotation axis 94, a swivel joint tie rod 1 95, a tie rod 1 rotation axis 96, a swivel joint tie rod 2 97, a tie rod 2 rotation axis 98, a wrist swivel joint similar mechanism counterweight 99, a swivel joint roller ring 1100, a roller ring bearing 101, a bearing inner ring 102, a swivel joint roller ring 2 103, a wrist swivel joint mounting bracket 104, and a wrist swivel joint counterweight 105; a force sensor is connected in series between the lifting ear 90 and the double-threaded adjustment rod 91; the wrist swivel joint similar mechanism suspension 78 is connected to the wrist joint extension 18 and the wrist swivel joint 19 assembly to achieve static balance of the assembly, and the center of mass of the assembly is adjusted to the axis of the wrist swivel joint upper suspension rod 92 by adjusting the wrist swivel joint similar mechanism counterweight 99 and the wrist swivel joint counterweight 105 to achieve random balance;

[0121] The wrist end effector similar suspension 79 is composed of the wrist end effector upper suspension rod 106, the wrist end effector similar triangle plate 107, the upper suspension rod rotation axis 108, the wrist end effector pull rod 1 109, the pull rod 1 rotation axis 110, the wrist end effector pull rod 2 111, the pull rod 1 rotation axis 112, the wrist end effector similar mechanism counterweight 113, the wrist end effector roller ring 1114, the roller ring bearing 101, the bearing inner ring 102, the wrist end effector roller ring 2 115, a wrist end effector mounting bracket 116, and a wrist end effector counterweight 117; the wrist end effector similar mechanism suspension 79 is connected to the wrist end effector 20, and is used to achieve static balance of the wrist end effector 20, and the center of mass of the wrist end effector 20 is adjusted to the axis of the wrist end effector upper suspension rod 106 by adjusting the wrist end effector similar mechanism counterweight 113 and the wrist end effector counterweight 117 to achieve random balance;

[0122] The upper crossbeam 76, the wrist swivel joint similar mechanism suspension 78, and the wrist end effector similar suspension 79 form a large parallelogram-like mechanism. By adjusting the position of the upper crossbeam counterweight 77, as well as the installation positions of the wrist swivel joint similar mechanism suspension 78 and the wrist end effector similar suspension 79 on the upper crossbeam 76, the center of mass of the large assembly of the wrist joint extension 18, the wrist swivel joint 19, and the wrist end effector is adjusted to the axis of the U-shaped suspension 75 to achieve the arbitrary balance of the large assembly.

[0123] A total of 30 force sensors are arranged in the air-floating support device to form a force monitoring system for monitoring the stress state of each movable component before and after assembly; among them, force sensors 201-204 are used to monitor the stress of the shoulder end effector 7 (the small roller ring 25 and the large roller ring 26 at the shoulder end are weighed and peeled in advance); force sensors 205-208 are used to monitor the stress of the shoulder swivel joint 8 and the shoulder joint extension 9 assembly (the weight of the shoulder swivel joint posture adjustment mechanism 22 and the four height adjustment mechanisms 23 are weighed and peeled in advance); force sensors 209-212 are used to monitor the stress of the shoulder yaw joint 10 (the weight of the four shoulder yaw joint posture fine-tuning mechanisms 42 are weighed and peeled in advance); force sensors 213-216 are used to monitor the stress of the shoulder pitch joint 11; force sensors 217-220 are used to monitor the stress of the elbow pitch joint 13 (the weight of the four elbow pitch joint posture adjustment mechanisms 53 are weighed and peeled in advance); force sensors Force sensors 221-223 are used to monitor the force of the central control assembly 14 (the weights of the three central control assembly posture adjustment mechanisms 58, the first central control assembly mounting bracket 59, and the first central control assembly mounting bracket 60 are weighed and peeled in advance); force sensors 224-227 are used to monitor the force of the wrist pitch joint 16 (the weights of the four wrist pitch joint posture adjustment mechanisms 66 are weighed and peeled in advance); force sensor 228 is used to monitor the force of the wrist yaw joint 17 (the weights of the wrist yaw joint The weight of the wrist joint suspension 67 is weighed and peeled off in advance); the force sensor 229 is used to monitor the force of the wrist joint extension 18 and the wrist swivel joint 19 combination (the weight of the wrist swivel joint similar mechanism suspension 78 is weighed and peeled off); the force sensor 230 is used to monitor the force of the wrist joint extension 18, the wrist swivel joint 19, and the wrist end effector 20 combination (the weight of the wrist swivel joint similar mechanism suspension 78 and the wrist end effector similar suspension 79 are weighed and peeled off).

[0124] The air-floating support device is placed on the air-floating platform, and the air distribution device supplies air to the plane air foot 28 of each air-floating support device, and the air pressure is 0.6MPa, so that the air-floating support device floats, and the air film is used to reduce the friction of movement; through the division of the degrees of freedom of movement, the air-floating support device is divided into four components: the shoulder pitch motion component, the shoulder translation motion component, the elbow translation motion component, and the wrist motion component. Through the reasonable design of the air-floating support device, the large-range movement of each motion joint of the space multi-degree-of-freedom manipulator is supported, and the folding state of the manipulator can be realized;

[0125] The low-stress assembly method of a multi-degree-of-freedom robotic arm based on multi-point support described in this article is as follows:

[0126] Step 1: Level the shoulder pitch air-floating support frame mechanism 21; install the shipboard 24 on the shoulder pitch air-floating support frame mechanism 21, one side of the shipboard 24 is rotatably connected to the bearing 33 through the pitch shaft 36, and the other side of the shipboard 24 is fixedly connected to the roller ring 35; by adjusting the positions of the two rollers 30 and the installation position of the roller ring 35 on the shipboard 24, ensure the parallelism of the axis of the roller ring 35 and the plane of the air-floating platform;

[0127] Step 2: Install the shoulder swivel joint 8 and the shoulder joint extension 9 assembly on the shoulder swivel joint posture adjustment mechanism 22 and connect it to the shipboard 24, adjust the axis of the shoulder joint extension 9 through four height adjustment mechanisms 23 to ensure that the axis of the joint extension 9 is coaxial with the roller ring 35; record the forces of the force sensors 205-208;

[0128] Step 3: Connect the shoulder end effector 7 with the small roller ring 25 and the large roller ring 26 at the shoulder end, measure and adjust the coaxiality of the small roller ring 25 and the large roller ring 26 at the shoulder end effector 7, and weigh and calculate and adjust the center of mass of the assembly to ensure that the center of mass of the assembly is located on the axis of the shoulder end effector 7;

[0129] Step 4: Install the shoulder end effector 7 on the end position adjustment mechanism 27, measure and adjust the coaxiality of the shoulder end effector 7 and the output shaft of the shoulder rotary joint 8, and record the forces of the sensors 201 to 204;

[0130] Step 5: dock the shoulder end effector 7 and the shoulder swivel joint 8 on the shipboard 24; since there is still an adjustment error in the docking, additional stress will still be generated during the docking and assembly of the two parts. Through the visualization of the force sensors 201-208, the degree of freedom that needs to be adjusted is determined, and the force change of the force sensors 201-208 is controlled within 5%; until the docking and assembly are completed; re-measure the coaxiality between the two;

[0131] Step 6: Adjust the counterweight 37 on the shipboard 24 so that the center of mass of the equipment and tooling assembly on the shipboard 24 is located on the axis of the joint extension 9 to achieve the random balance of the assembly;

[0132] Step 7: Install the shoulder yaw joint 10 on the shoulder translation bracket 2, lower the shoulder yaw joint 10 to the lowest point through three double-threaded adjustment rods 40, and adjust the posture of the shoulder yaw joint 10 through four shoulder yaw joint posture fine-tuning mechanisms 42 to ensure the parallelism of the output shaft axis of the shoulder yaw joint 10 and the ground, and the verticality of the fixed shaft axis and the ground;

[0133] Step 8: Connect the shoulder pitch joint 11 to the four shoulder pitch joint posture fine-tuning mechanisms 47, measure and adjust the parallelism between the axis of the shoulder pitch joint 11 fixture and the ground, and the verticality between the axis of the output shaft and the ground; record the forces of the force sensors 213-216;

[0134] Step nine: lift the shoulder yaw joint 10 through three double-threaded adjustment rods 40 and dock it with the shoulder pitch joint 11; adjust the posture of the shoulder yaw joint 10 through four shoulder yaw joint posture fine-tuning mechanisms 42, control the force change of the force sensors 209-216 within 5%, and ensure the height difference between the axis of the shoulder yaw joint 10 and the shoulder joint extension 9; re-measure the coaxiality of the shoulder pitch joint 11 and the shoulder yaw joint 10, and the height of the axis to the ground;

[0135] Step 10: dock the shoulder yaw joint 10 with the shoulder joint extension 9; control the force change of the force sensors 201-216 within 5% by adjusting the terminal posture adjustment mechanism 27, the shoulder swivel joint posture adjustment mechanism 22, the shoulder yaw joint posture fine-tuning mechanism 42, and the shoulder pitch joint posture fine-tuning mechanism 47; re-measure the coaxiality and axis height between the single machines;

[0136] Step 11: Conduct dynamic balance tests of the shoulder swivel joint 8, the shoulder yaw joint 10, and the shoulder pitch joint 11 in sequence through the ground inspection equipment; confirm that the force change of the force sensors 201-216 is controlled within 5%; otherwise, perform iterative measurement and adjustment;

[0137] Step 12: Fix the shoulder end effector 7 to the assembly support vehicle as the fixed end of the space robot arm assembly, and start the subsequent assembly work;

[0138] Step 13: The first arm 12 is mounted on the two first arm brackets 3, and the axis height of the first arm 12 and the coaxiality with the shoulder pitch joint 11 are adjusted by four threaded rods 49;

[0139] Step 14: Install the elbow pitch joint 13 on the elbow translation bracket 4, and adjust the posture of the elbow pitch joint 13 through the four elbow pitch joint posture adjustment mechanisms 53 to ensure the parallelism of the fixed axis of the elbow pitch joint 13 and the ground, the verticality of the output axis and the ground, and the coaxiality with the first arm 12; record the forces of the force sensors 217-220; first raise the air floating support plate 56 to the highest point through the three double-threaded adjustment rods 54;

[0140] Step 15: Assemble the central control assembly 14, the first central control assembly mounting bracket 59, the first central control assembly mounting bracket 60, the three central control assembly posture adjustment mechanisms 58, and the air floating plate 57, and adjust the verticality between the axis of the central control assembly 14 and the air floating plane of the air floating plate 57 through the central control assembly posture adjustment mechanism 58; record the forces of the force sensors 221-223;

[0141] Step 16: dock the large assembly formed by the central control assembly 14 and the mounting bracket with the air floating support plate, and lower the large assembly through three double-threaded adjustment rods 54 to dock with the elbow pitch joint 13, and control the force change of the force sensors 217-223 within 5%; precisely measure the coaxiality and axis height of the elbow pitch joint 13 and the central control assembly 14;

[0142] Step 17: Assemble and dock the first arm 12 with the shoulder pitch joint 11 and the elbow pitch joint 13 to form a front half arm; monitor the state of the force sensor and control the force change of the force sensors 201-223 within 5%; accurately measure the axis size of the front half arm and the coaxiality between the single machines;

[0143] Step 18: Install the second arm 15 on the second arm bracket 5, and adjust the axis height of the second arm 15 and the coaxiality with the central control assembly 14 through the four threaded rods 62;

[0144] Step 19: Install the wrist pitch joint 16 on the wrist bracket 6, and adjust the posture of the wrist pitch joint 16 through the four wrist pitch joint posture adjustment mechanisms 66 to ensure the parallelism of the fixed axis of the wrist pitch joint 16 and the ground, the verticality of the output axis and the ground, and the coaxiality with the second arm 15; record the forces of the force sensors 224-227;

[0145] Step 20: Connect the wrist yaw joint 17 to the wrist yaw joint suspension 67, adjust the center of mass of the assembly to the axis of the fixed axis of the wrist yaw joint 17, and achieve a dynamic balance state of the wrist yaw joint 17; adjust the double-threaded adjustment rod 84 to adjust the wrist yaw joint suspension 67 to the shortest state;

[0146] Step 21: Connect the wrist yaw joint 17 and the wrist yaw joint suspension 67 assembly to the wrist bracket 6, and adjust the transverse adjustment block 80 and the longitudinal adjustment block 81 to make the fixed axis of the wrist yaw joint 17 coaxial with the output axis of the wrist pitch joint 16; record the force of the force sensor 228;

[0147] Step 22: Adjust the double-threaded adjustment rod 84 to dock the wrist yaw joint 17 with the wrist pitch joint 16, and control the force change of the force sensors 224-228 within 5% by fine-tuning the four wrist pitch joint posture adjustment mechanisms 66; precisely measure the axis height of the fixed axis of the wrist pitch joint 16 and its coaxiality with the second arm, the axis height of the output shaft of the wrist yaw joint 17, and the coaxiality of the fixed axis with the output shaft of the wrist pitch joint 16;

[0148] Step 23: Use ground inspection equipment to perform a motion test on the wrist pitch joint 16 to confirm that the force change of the force sensors 224-228 is controlled within 5% within the allowable angle range; otherwise, continue to adjust according to step 22 until the requirements are met;

[0149] Step 24: dock and weigh the wrist joint extension 18 and the wrist swivel joint 19 to form a small assembly; assemble the small assembly with the wrist swivel joint similar mechanism suspension 78 to form a medium assembly, forming a parallelogram similar mechanism, and adjust the center of mass of the medium assembly to the axis of the wrist swivel joint upper suspension rod 92 by adjusting the wrist swivel joint similar mechanism counterweight 99 and the wrist swivel joint counterweight 105, and achieve random balance; the principle of the similar mechanism is shown in the figure, and points A and B in the figure are the swivel joint roller ring 1100 and the swivel joint roller ring 2 installed on the product 103, A' and B' are the axes of the rotation axis 96 of the pull rod 1 and the rotation axis 98 of the pull rod 2. As long as the wrist wrist joint extension 18 and the center of mass of the wrist swivel joint 19 are adjusted to point C (located at the intersection of the axis of the output shaft of the wrist swivel joint 19 and the axis of the suspension rod 106) by adjusting the wrist swivel joint counterweight 105, and the center of mass of the wrist swivel joint upper suspension rod 92, the wrist swivel joint similar triangle plate 93, the swivel joint pull rod 1 95, and the swivel joint pull rod 2 97 combination is adjusted to point C' by adjusting the wrist swivel joint similar mechanism counterweight 99, the real-time zero gravity simulation of the combination in the wrist swivel joint can be realized; record the force of the force sensor 29;

[0150] Step 25: The principle is the same as step 24. The wrist end effector 20 and the wrist end effector similar suspension 79 are assembled to form a small assembly, forming a parallelogram-like mechanism. The center of mass of the wrist end effector 20 is adjusted to the axis of the wrist end effector upper suspension rod 106 by adjusting the wrist end effector similar mechanism counterweight 113 and the wrist end effector counterweight 117 to achieve random balance.

[0151] Step 26: The principle is the same as that of step 24. The assembly of step 24 and step 25 are installed with the upper beam 76 to form a large assembly, which forms a large parallelogram-like mechanism. By adjusting the position of the upper beam counterweight 77, the installation position of the wrist swivel joint-like mechanism suspension 78, and the wrist end effector-like suspension 79 on the upper beam 76, the center of mass of the large assembly is adjusted to the axis of the U-shaped suspension 75, so as to achieve the random balance of the large assembly around the axis of the U-shaped suspension 75; record the force of the force sensor 30;

[0152] Step 27: Use the ground inspection equipment to perform a motion test on the wrist swivel joint 19 to confirm that the force change of the force sensor 229 is controlled within 5% within the allowable angle range; otherwise, continue to adjust according to steps 25 and 26 until the requirements are met;

[0153] Step 28: Confirm the routing of the steel wire rope 73 according to the diagram; prepare the counterweight 118 in advance, and use half of the force of the force sensor 30 before peeling as the standard value for preparing the counterweight 118; connect the large assembly formed in step 26 with the steel wire rope 73 on the wrist bracket 6 to form a complete wrist assembly, and adaptively adjust the counterweight 118 to control the force change of the force sensors 224-230 within 5%; accurately measure the axis height and coaxiality of each single machine;

[0154] Step 29: Use ground inspection equipment to perform motion tests on the wrist pitch joint 16, the wrist yaw joint 17, and the wrist swivel joint 19 to confirm that the force change of the force sensors 224-230 is controlled within 5% within the allowable angle range; otherwise, continue to adjust according to steps 22-26 until the requirements are met;

[0155] Step 30: dock the second arm 15 with the central control assembly 14 and the wrist pitch joint 16 to form a complete arm; monitor the state of the force sensor and control the force change of the force sensors 201-230 within 5%; precisely measure the axis size of the robot arm and the coaxiality between the single machines and all DH parameters;

[0156] Step 31: Perform single-joint motion tests and multi-joint linkage tests on the seven joints of the space robot arm to confirm the low-stress assembly state of the robot arm.

[0157] In a possible implementation, through the combination of the above-mentioned air-floating support system, a low-stress ground assembly of a multi-degree-of-freedom motion mechanism can be achieved to realize the effect of ground simulation of the on-orbit gravity environment.

[0158] The present application provides a low-stress assembly method for a multi-degree-of-freedom robotic arm, which is implemented by relying on an air floating support device, a force monitoring system, an air floating platform and an air distribution device. When the multi-degree-of-freedom robotic arm is assembled by the method, the effect of low-stress assembly and movement based on the air floating platform can be achieved.

[0159] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0160] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0161] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. An air-floating support system for low-stress assembly of a multi-degree-of-freedom manipulator with multi-point support force feedback, characterized in that: It includes air-floating support device, force monitoring system, air-floating platform and air distribution device; The air-floating support device is placed on the air-floating platform, and air is supplied to the plane of each air-floating support device through the air distribution device, so that the air-floating support device floats; The air-floating support device is used to simulate the zero-gravity state of the multi-degree-of-freedom space robot arm on the ground, reduce or eliminate the assembly stress of the product, and reduce the influence of gravity on the function and performance of the space robot arm product; The force monitoring system includes a plurality of force sensors arranged on the air-floating support device, which are used to monitor the force state of each movable part before and after assembly; The air-floating support device comprises: A shoulder pitch bracket (1) for low stress assembly of the shoulder end and shoulder swivel joint; and A shoulder translation bracket (2) for low-stress assembly of the shoulder yaw joint and the shoulder pitch joint; and Two first arm brackets (3) are provided, and are used for supporting and fixing the first arm (12) of the space robot arm; and An elbow translation bracket (4) is used for low-stress assembly of a space robot elbow pitch joint (13) and a space robot central control assembly (14); and A second arm support (5) is used for supporting and fixing the second arm (15) of the space robot arm; and A wrist bracket (6) is used for low-stress assembly of a space robot arm wrist pitch joint (16), a space robot arm wrist yaw joint (17), a space robot arm wrist joint extension (18), a space robot arm wrist swivel joint (19) assembly, and a space robot arm wrist end effector (20); The shoulder pitch support (1) comprises: The shoulder pitch air-floating support frame mechanism (21) provides an operating platform for assembly, and comprises four shoulder pitch support plane air feet, a frame (29), a roller (30), a bearing seat (31), a roller seat (32), and a bearing a (33); the shoulder pitch support plane air feet are connected to the bottom of the frame (29) through a connecting screw (34) to provide air buoyancy for the frame (29); a support frame is arranged on each side of the frame (29), a bearing a (33) is fixed on the top end of one of the support frames, a roller seat (32) is fixed on the top end of the other support frame, two bearing seats (31) are arranged on the roller seat (32), and a roller ring (35) on the frame (29) is tangent to the two rollers (30); the shoulder swivel joint posture adjustment mechanism (22) and four height adjustment mechanisms (23) are arranged on the shipboard (24); and A shipboard (24) is located above the frame vehicle (29), one side of the shipboard (24) is rotatably connected to the bearing a (33) via a pitch axis (36), and the other side of the shipboard (24) is fixedly connected to a roller ring (35); and The small roller ring (25) at the end of the shoulder and the large roller ring (26) at the end of the shoulder are connected to the end effector (7) of the shoulder of the space robot arm, and there is a preset range of coaxiality between the three, so that the end effector (7) of the shoulder of the space robot arm can rotate freely around its own rotation axis after being installed on the end position adjustment mechanism (27); The shoulder translation support (2) comprises four shoulder translation support plane air feet, a shoulder translation support body (38), a fixing plate (39), three double-threaded adjustment rods a (40), an adjustment plate (41), four shoulder yaw joint attitude fine-tuning mechanisms (42), a shoulder yaw joint support frame (43), an upper hanging plate (44), a bearing b (45), a rotating hanging plate (46), and four shoulder pitch joint attitude fine-tuning mechanisms (47); The shoulder translation support plane air foot is connected to the bottom of the shoulder translation support body (38) through a connecting screw (34) to provide air buoyancy for the shoulder translation support body (38); a fixing plate (39) is fixed on the shoulder translation support body (38), and the height and posture of the adjustment plate (41) are roughly adjusted through three double-threaded adjustment rods a (40); four shoulder yaw joint posture fine-adjustment mechanisms (42) are installed on the adjustment plate (41), and a force sensor is connected in series in each shoulder yaw joint posture fine-adjustment mechanism (42); a shoulder yaw joint support frame (43) is installed on the shoulder translation support body (38), and an upper hanging plate (44) is installed thereon, and a rotating hanging plate (46) is connected to the upper hanging plate through a bearing b (45); The elbow translation support (4) comprises four elbow translation support plane air feet, an elbow translation support body (52), four elbow pitch joint posture adjustment mechanisms (53), three double-threaded adjustment rods b (54), a screw support ring (55), an air floating support plate (56), an air floating plate (57), three central control assembly posture adjustment mechanisms (58), a first central control assembly mounting bracket (59), and a second central control assembly mounting bracket (60); The elbow translation support plane air foot is connected to the bottom of the elbow translation support body (52) through a connecting screw (34) and is used to provide air buoyancy for the elbow translation support body (52); A force sensor is connected in series in each elbow pitch joint posture adjustment mechanism (53), with a total of four; The air-floating support plate (56) is installed on the elbow translation support body (52) through three double-threaded adjustment rods b (54) and a screw support ring (55) to serve as a floating base of the air-floating plate (57); after the first central control assembly mounting bracket (59), the second central control assembly mounting bracket (60) and the space robot arm central control assembly (14) are installed, they are fixed on the air-floating plate (57) through each central control assembly posture adjustment mechanism (58), and each central control assembly posture adjustment mechanism (58) is connected in series with a force sensor, for a total of three; air is ventilated between the air-floating plate (57) and the air-floating support plate (56) to form an air film, so that the air-floating plate (57) floats, thereby offsetting gravity and reducing motion friction; The elbow translation bracket (4) is used for low-stress assembly of a space robot arm elbow pitch joint (13) and a space robot arm central control assembly (14); The wrist support (6) comprises eight wrist support plane air feet, a wrist support body (65), four wrist pitch joint posture adjustment mechanisms (66), a wrist yaw joint suspension (67), a column support (68), a fixed column (69), a rotary column (70), a sliding sleeve (71), a fixed pulley (72), a wire rope (73), a movable pulley (74), a U-shaped suspension (75), an upper crossbeam (76), an upper crossbeam counterweight (77), a wrist rotary joint similar mechanism suspension (78), and a wrist end effector similar suspension (79); The wrist support body (65) is the main part of the wrist support (6) and is used for integration, installation, connection, support and rigidity maintenance of various components; A force sensor is connected in series in each wrist pitch joint posture adjustment mechanism (66); The wrist yaw joint suspension (67) includes a pull rod (82) and a slewing bearing (83); a force sensor is connected in series between the pull rod (82) and the slewing bearing (83); The column support (68) is installed above the wrist support body (65); The fixed column (69) is fixed on the column bracket (68), and the rotary column (70) is installed in cooperation with the fixed column (69) and can rotate freely in the fixed column (69); The sliding sleeve (71) adapts to the position deviation of the U-shaped hanging (75) and the upper crossbeam (76) during assembly, and slides freely on the horizontal axis of the rotary column (70); Pulleys for routing the wire rope are installed in the column bracket (68), the fixed column (69) and the rotating column (70), wherein the fixed pulley (72) is installed at the bottom of the sliding sleeve (71), the upper end of the U-shaped hanging (75) is connected to the movable pulley (74), and the lower end is connected to the upper crossbeam (76); the wire rope (73) passes through the fixed pulley (72), the movable pulley (74) and the pulleys in the rotating column (70), the fixed column (69) and the column bracket (68) in sequence, and is connected to the counterweight a (118), so that the counterweight a (118) offsets the gravity of the wrist rotating assembly; The upper beam counterweight (77) is installed on the upper beam (76), and the wrist rotation assembly is assisted to achieve balance in any situation by adjusting the mass and position of the upper beam counterweight (77); The wrist swivel joint similar mechanism suspension (78) is connected to the space robot arm wrist joint extension (18) and the space robot arm wrist swivel joint (19) assembly to achieve static balance of the assembly. By adjusting the wrist swivel joint similar mechanism counterweight (99) and the wrist swivel joint counterweight (105), the center of mass of the assembly is adjusted to the axis of the wrist swivel joint upper suspension rod (92) to achieve random balance. The wrist end effector similar suspension (79) is connected to the space manipulator wrist end effector (20) and is used to achieve static balance of the space manipulator wrist end effector (20). The center of mass of the space manipulator wrist end effector (20) is adjusted to the axis of the wrist end effector upper suspension rod (106) by adjusting the wrist end effector similar mechanism counterweight (113) and the wrist end effector counterweight (117) to achieve random balance. The upper crossbeam (76), the wrist swivel joint similar mechanism suspension (78), and the wrist end effector similar suspension (79) form a large parallelogram-like mechanism. By adjusting the position of the upper crossbeam counterweight (77) and the installation positions of the wrist swivel joint similar mechanism suspension (78) and the wrist end effector similar suspension (79) on the upper crossbeam (76), the center of mass of the large assembly of the space robot wrist joint extension (18), the space robot wrist swivel joint (19), and the wrist end effector is adjusted to the axis of the U-shaped suspension (75) to achieve the random balance of the large assembly.

2. The air floating support system according to claim 1, characterized in that: The force monitoring system includes at least thirty force sensors; in The first group of force sensors includes at least four force sensors for monitoring the force of the end effector (7) at the shoulder of the space robot arm; The second group of force sensors includes at least four force sensors, which are used to monitor the force applied to the combination of the shoulder swivel joint (8) and the shoulder joint extension (9) of the space robot arm; The third group of force sensors includes at least four force sensors, which are used to monitor the force of the shoulder yaw joint (10) of the space robot arm; The fourth group of force sensors includes at least four force sensors, which are used to monitor the force of the pitch joint (11) of the shoulder of the space robot arm; The fifth group of force sensors includes at least four force sensors for monitoring the force of the elbow pitch joint (13) of the space manipulator; The sixth group of force sensors includes at least three force sensors, which are used to monitor the force applied to the central control assembly (14) of the space robot arm; The seventh group of force sensors includes at least four force sensors, which are used to monitor the force of the pitch joint (16) of the wrist of the space manipulator; The eighth group of force sensors is used to monitor the force of the yaw joint (17) of the wrist of the space robot arm; A ninth group of force sensors, used to monitor the force applied to the space robot arm wrist joint extension piece (18) and the space robot arm wrist swivel joint (19) assembly; The tenth group of force sensors is used to monitor the force applied to the assembly of the space robot arm wrist joint extension piece (18), the space robot arm wrist swivel joint (19), and the space robot arm wrist end effector (20).

3. The air floating support system according to claim 1, characterized in that: The multi-degree-of-freedom spatial robot is divided into degrees of freedom according to the configuration and layout status, and the air floating support device is divided into four components: shoulder pitch motion component, shoulder translation motion component, elbow translation motion component, and wrist motion component. The shoulder, elbow, and wrist are selected as needed for grouping and fixing to realize the movement of each motion joint of the spatial multi-degree-of-freedom robot.

4. The air floating support system according to claim 1, characterized in that: The air-floating support device is used for low-stress assembly between the individual machines during the assembly phase, while taking into account the motion test requirements of the robotic arm, to achieve the morphological transformation of the robotic arm's assembly configuration, test configuration, and folded configuration, as well as the low-stress state of each moving joint during three-dimensional motion.

5. A multi-degree-of-freedom robotic arm low-stress assembly method based on multi-point support force feedback, characterized in that: include: Step 1: Leveling the shoulder pitch air-floating support frame mechanism (21); installing the shipboard (24) on the shoulder pitch air-floating support frame mechanism (21), one side of the shipboard (24) is rotatably connected to the bearing a (33) via the pitch shaft (36), and the other side of the shipboard (24) is fixedly connected to the roller ring (35); by adjusting the positions of the two rollers (30) and the installation position of the roller ring (35) on the shipboard (24), the parallelism between the axis of the roller ring (35) and the plane of the air-floating platform is ensured; Step 2: Install the assembly of the space robot shoulder swivel joint (8) and the space robot shoulder joint extension (9) on the shoulder swivel joint posture adjustment mechanism (22), and connect it to the shipboard (24); adjust the axis of the space robot shoulder joint extension (9) through four height adjustment mechanisms (23) to ensure that the axis of the space robot joint extension (9) is coaxial with the roller ring (35); record the force of the second group of force sensors; Step 3: Connect the space robot shoulder end effector (7) with the small roller ring (25) at the shoulder end and the large roller ring (26) at the shoulder end, measure and adjust the coaxiality of the small roller ring (25) at the shoulder end and the large roller ring (26) at the shoulder end and the space robot shoulder end effector (7), weigh and calculate and adjust the center of mass of the assembly to ensure that the center of mass of the assembly is located on the axis of the space robot shoulder end effector (7); Step 4: Install the end effector (7) of the shoulder of the space robot arm on the end position adjustment mechanism (27), measure and adjust the coaxiality of the output shaft of the end effector (7) of the shoulder of the space robot arm and the shoulder rotary joint (8) of the space robot arm, and record the force of the first group of force sensors; Step 5: docking the space robot shoulder end effector (7) and the space robot shoulder swivel joint (8) on the shipboard (24); Step 6: Adjust the counterweight b (37) on the shipboard (24) so ​​that the center of mass of the equipment and tooling assembly on the shipboard (24) is located on the axis of the space robot arm joint extension (9) to achieve the random balance of the assembly; Step 7: Install the shoulder yaw joint (10) of the space robot arm on the shoulder translation bracket (2), first lower the shoulder yaw joint (10) of the space robot arm to the lowest point through three double-threaded adjustment rods a (40), and adjust the posture of the shoulder yaw joint (10) of the space robot arm through four shoulder yaw joint posture fine-tuning mechanisms (42) to ensure the parallelism of the output shaft axis of the shoulder yaw joint (10) of the space robot arm and the ground, and the verticality of the fixed shaft axis and the ground; Step 8: Connect the shoulder pitch joint (11) of the space robot arm to the four shoulder pitch joint attitude fine-tuning mechanisms (47), measure and adjust the parallelism between the axis of the fixer of the shoulder pitch joint (11) of the space robot arm and the ground, and the verticality between the axis of the output shaft and the ground; record the force of the fourth group of force sensors; Step nine: lift the space robot arm shoulder yaw joint (10) through three double-threaded adjustment rods a (40) and dock it with the space robot arm shoulder pitch joint (11); adjust the posture of the space robot arm shoulder yaw joint (10) through four shoulder yaw joint posture fine-tuning mechanisms (42), control the force changes of the third group of force sensors and the fourth group of force sensors within a preset range, and ensure the height difference between the axis of the space robot arm shoulder yaw joint (10) and the space robot arm shoulder joint extension (9); re-measure the coaxiality of the space robot arm shoulder pitch joint (11) and the space robot arm shoulder yaw joint (10), and the height of the axis to the ground; Step 10: docking the space robot shoulder yaw joint (10) with the space robot shoulder joint extension (9); controlling the force changes of the first to fourth groups of force sensors within a preset range by adjusting the end position adjustment mechanism (27), the shoulder swivel joint position adjustment mechanism (22), the shoulder yaw joint attitude fine-tuning mechanism (42), and the shoulder pitch joint attitude fine-tuning mechanism (47); re-measuring the coaxiality and axis height between the single machines; Step 11: Perform a dynamic balance test of the space robot arm shoulder swivel joint (8), a dynamic balance test of the space robot arm shoulder yaw joint (10), and a dynamic balance test of the space robot arm shoulder pitch joint (11) in sequence through ground inspection equipment; confirm that the force changes of the first to fourth groups of force sensors are controlled within a preset range; otherwise, perform iterative measurement and adjustment; Step 12: Fix the space robot shoulder end effector (7) to the assembly support vehicle as the fixed end of the space robot assembly, and start the subsequent assembly work; Step 13: The first arm rod (12) of the space robot arm is mounted on two first arm rod brackets (3), and the axis height of the first arm rod (12) of the space robot arm and the coaxiality with the pitch joint (11) of the shoulder of the space robot arm are adjusted by four threaded rods a (49); Step 14: Install the elbow pitch joint (13) of the space robot arm on the elbow translation bracket (4), and adjust the posture of the elbow pitch joint (13) of the space robot arm through four elbow pitch joint posture adjustment mechanisms (53) to ensure the parallelism of the fixed axis of the elbow pitch joint (13) of the space robot arm and the ground, the verticality of the output axis and the ground, and the coaxiality with the first arm (12) of the space robot arm; record the force of the fifth group of force sensors; first raise the air floating support plate (56) to the highest point through three double-threaded adjustment rods b (54); Step 15: Assemble the space robot arm central control assembly (14), the first central control assembly mounting bracket (59), the second central control assembly mounting bracket (60), the three central control assembly posture adjustment mechanisms (58), and the air floating plate (57), and adjust the verticality of the axis of the space robot arm central control assembly (14) and the air floating plane of the air floating plate (57) through the central control assembly posture adjustment mechanism (58); Record the force of the sixth group of force sensors; Step 16: docking the large assembly formed by the space robot arm central control assembly (14) and the mounting bracket with the air floating support plate, and at the same time lowering the large assembly through three double-threaded adjustment rods b (54) to dock with the space robot arm elbow pitch joint (13), and controlling the force changes of the fifth group of force sensors and the sixth group of force sensors within a preset range; measuring the coaxiality and axis height of the space robot arm elbow pitch joint (13) and the space robot arm central control assembly (14); Step 17: Assemble and dock the first arm rod (12) of the space manipulator with the shoulder pitch joint (11) of the space manipulator and the elbow pitch joint (13) of the space manipulator to form a front half arm; control the force changes of the first to sixth groups of force sensors within a preset range; measure the axis size of the front half arm and the coaxiality between the single units; Step 18: Install the second arm rod (15) of the space robot arm on the second arm rod bracket (5), and adjust the axis height of the second arm rod (15) of the space robot arm and the coaxiality with the space robot arm central control assembly (14) through four threaded rods b (62); Step 19: Mount the wrist pitch joint (16) of the space manipulator on the wrist bracket (6), and adjust the posture of the wrist pitch joint (16) of the space manipulator through four wrist pitch joint posture adjustment mechanisms (66) to ensure the parallelism of the fixed axis of the wrist pitch joint (16) of the space manipulator and the ground, the verticality of the output axis and the ground, and the coaxiality with the second arm (15) of the space manipulator; Record the force of the seventh group of force sensors; Step 20: Connect the space robot arm wrist yaw joint (17) to the wrist yaw joint suspension (67), adjust the mass center of the assembly to the fixed axis of the space robot arm wrist yaw joint (17), and achieve a dynamic balance state of the space robot arm wrist yaw joint (17); adjust the double-threaded adjustment rod c (84) to adjust the wrist yaw joint suspension (67) to the shortest state; Step 21: Connect the space robot arm wrist yaw joint (17) and the wrist yaw joint suspension (67) assembly to the wrist bracket (6), and adjust the transverse adjustment block (80) and the longitudinal adjustment block (81) to make the fixed axis of the space robot arm wrist yaw joint (17) and the output axis of the space robot arm wrist pitch joint (16) coaxial; record the force of the eighth group of force sensors; Step 22: Adjust the double-threaded adjustment rod c (84) to dock the yaw joint (17) of the wrist of the space robot arm with the pitch joint (16) of the wrist of the space robot arm, and control the force changes of the seventh group of force sensors and the eighth group of force sensors within a preset range by fine-tuning the four wrist pitch joint posture adjustment mechanisms (66); measure the axis height of the fixed axis of the pitch joint (16) of the wrist of the space robot arm and its coaxiality with the second arm, the axis height of the output axis of the yaw joint (17) of the wrist of the space robot arm, and the coaxiality of the fixed axis with the output axis of the pitch joint (16) of the wrist of the space robot arm; Step 23: Use ground inspection equipment to perform a motion test on the pitch joint (16) of the wrist of the space manipulator to confirm that within the allowable angle range, the force changes of the seventh group of force sensors and the eighth group of force sensors are controlled within a preset range; otherwise, continue to adjust according to step 22 until the requirements are met; Step 24: docking and weighing the space manipulator wrist joint extension (18) and the space manipulator wrist swivel joint (19) to form a first assembly; assembling the first assembly and the wrist swivel joint similar mechanism suspension (78) to form a second assembly to form a parallelogram similar mechanism; adjusting the wrist swivel joint similar mechanism counterweight (99) and the wrist swivel joint counterweight (105) to adjust the center of mass of the middle assembly to the axis of the wrist swivel joint upper suspension rod (92) to achieve random balance; recording the force of the ninth group of force sensors; Step 25: Assemble the space manipulator wrist end effector (20) and the wrist end effector similar suspension (79) to form a third assembly, forming a parallelogram-like mechanism, and adjust the center of mass of the space manipulator wrist end effector (20) to the axis of the wrist end effector upper suspension rod (106) by adjusting the wrist end effector similar mechanism counterweight (113) and the wrist end effector counterweight (117) to achieve random balance; Step 26: The second assembly and the third assembly are mounted on the upper crossbeam (76) to form a fourth assembly, forming a parallelogram-like mechanism. By adjusting the position of the upper crossbeam counterweight (77), the installation position of the wrist swivel joint-like mechanism suspension (78) and the wrist end effector-like suspension (79) on the upper crossbeam (76), the center of mass of the fourth assembly is adjusted to the axis of the U-shaped suspension (75), so as to achieve the fourth assembly being in random balance around the axis of the U-shaped suspension (75); Record the forces of the tenth group of force sensors; Step 27: Use ground inspection equipment to perform a motion test on the wrist swivel joint (19) of the space robot arm to confirm that within the allowable angle range, the force change of the ninth group of force sensors is controlled within a preset range; otherwise, continue to adjust according to steps 25 and 26 until the requirements are met; Step 28: Confirm the routing of the steel wire rope (73); prepare the counterweight a (118), and use half of the force of the tenth group of force sensors before peeling as the standard value for preparing the counterweight a (118); connect the fourth assembly formed in step 26 with the steel wire rope (73) on the wrist bracket (6) to form a complete wrist assembly, and adaptively adjust the counterweight a (118) so that the force changes of the seventh to tenth groups of force sensors are controlled within a preset range; measure the axis height and coaxiality of each unit; Step 29: Use ground inspection equipment to perform motion tests on the pitch joint (16), the yaw joint (17), and the swivel joint (19) of the wrist of the space manipulator to confirm that within the allowable angle range, the force changes of the seventh to tenth groups of force sensors are controlled within a preset range; otherwise, continue to adjust according to steps 22 to 26 until the requirements are met; Step 30: docking the second arm rod (15) of the space robot arm with the central control assembly (14) of the space robot arm and the pitch joint (16) of the wrist of the space robot arm to form a complete arm; monitoring the state of the force sensors to control the force changes of all force sensors within a preset range; measuring the axis size of the robot arm and the coaxiality between the single units and all DH parameters; Step 31: Perform single joint motion tests on seven joints of the space robot arm to confirm the low-stress assembly state of the robot arm.

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