Space manipulator suspends microgravity simulation device

Abstract

The present invention provides a space manipulator suspension microgravity simulation device, which belongs to the field of simulation experiments, and includes a mechanical swing arm installation platform, a six-degree-of-freedom platform and a camera. The target point on the six-degree-of-freedom platform is measured in real time, the position and attitude change of the six-degree-of-freedom platform are obtained, and the mechanical swing arm installation platform is controlled to follow the movement of the six-degree-of-freedom platform; the mechanical swing arm installation platform includes an omnidirectional mobile platform, a counterweight and a mechanical swing arm bracket, and the omnidirectional mobile platform moves omnidirectionally in a plane; the counterweight is used to balance the overall center of mass of the omnidirectional mobile platform and the mechanical swing arm; the mechanical swing arm bracket, the movement of which is used to compensate for the movement accuracy of the full mobile platform. The present invention eliminates the effect of the self-gravity of the mechanical arm on the attitude of the spacecraft when the mechanical arm is deployed, while retaining more degrees of freedom and range of motion of the mechanical arm, and adapting to the deployment range of the space manipulator in a larger range.

Description

Technical Field

[0001] The invention belongs to the field of simulation experiments and relates to a space manipulator suspension microgravity simulation device. Background Art

[0002] Using ground equipment to simulate the special working environment of a spacecraft to conduct tests and experiments in order to verify the structural performance of the spacecraft on the ground is a commonly used method in the aerospace field. It is also a strategy that takes into account both economy and timeliness in the development process.

[0003] In recent years, space manipulators or space robots have assumed increasingly important tasks in space exploration and development. They can replace astronauts in harsh space environments to complete a variety of tasks such as target capture, fault repair, garbage cleaning, and star catalog sampling. Space manipulators developed based on the micro-low gravity environment and application background of space often have characteristics such as long arm rods, multiple degrees of freedom, and low motor power. They cannot work directly in the ground gravity environment, and a microgravity simulation device is required to unload the gravity of the manipulator for experimental verification. Spacecraft that perform capture, maintenance, and detection tasks now mostly use dual manipulators with multiple degrees of freedom and a large range of motion to work together, which makes ground simulation verification more difficult and requires the design of more complex and accurate microgravity simulation devices and methods.

[0004] In the past, the deployment test of the robot arm in the microgravity simulation environment on the ground mostly adopted the air flotation method or the suspension method, and the robot arm was installed on a fixed simulation wall or a support vehicle. During the test, the freedom and range of the robot arm's deployment movement were greatly limited. In addition, since there was no need to consider the influence of the robot arm's force and torque on the fixed installation point, the main arm of the robot arm was mostly gravity unloaded, and the whole arm adopted double or single suspension points. Although the overall gravity of the robot arm was unloaded, the torque at the joint had a large deviation.

[0005] When the spacecraft uses a manipulator to perform target capture tests, the manipulator is installed on an air-floating platform or parallel mechanism with six degrees of freedom. The torque deviation at the root of the manipulator will have a great impact on the attitude of the spacecraft, causing the capture simulation test to fail. Sometimes, in order to more realistically simulate and verify the state of the spacecraft in the capture test, the movement of the manipulator is restricted. Summary of the invention

[0006] The problem to be solved by the present invention is to provide a space manipulator arm suspension microgravity simulation device, by constructing a set of mechanical swing arm systems that can actively control and respond quickly to control the positions of various suspension points of the space manipulator arm to follow the movement of the target, and by using a specially designed multi-point suspension structure to fully unload the gravity of the space manipulator arm and the gravity of multiple manipulator arm joints, thereby eliminating the effect of the manipulator arm's own gravity on the spacecraft's posture when the manipulator arm is deployed, while retaining more degrees of freedom and range of motion of the manipulator arm, and adapting to a larger range of deployment of the space manipulator arm.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a space manipulator suspension microgravity simulation device, comprising a mechanical swing arm mounting platform, a six-degree-of-freedom platform and a camera, wherein the six-degree-of-freedom platform is arranged on an air-floating platform;

[0008] The camera measures the target point on the six-degree-of-freedom table in real time, obtains the position and posture change of the six-degree-of-freedom table, and then controls the mechanical swing arm mounting platform to follow the movement of the six-degree-of-freedom table through the control system;

[0009] The mechanical swing arm mounting platform includes an omnidirectional mobile platform, a counterweight and a mechanical swing arm bracket. The omnidirectional mobile platform moves omnidirectionally in a plane; the counterweight is used to balance the overall center of mass of the omnidirectional mobile platform and the mechanical swing arm; the mechanical swing arm bracket, whose movement is used to compensate for the movement accuracy of the omnidirectional mobile platform;

[0010] The camera is mounted on the mechanical swing arm bracket, and the mechanical swing arm bracket ensures the precision movement of the space mechanical arm at the lower end relative to the six-free platform through gravity unloading and a follow-up component.

[0011] Furthermore, the gravity unloading and following assembly includes a mechanical swing arm A, a mechanical swing arm B, a constant tension assembly and a suspension assembly, wherein the mechanical swing arm A is mounted on a mechanical swing arm bracket and is located between two mechanical swing arms B, and is used to control the following movement of the suspension point at the root of the space robot arm;

[0012] The mechanical swing arm B is symmetrically installed on the mechanical swing arm bracket, corresponding to a space robot arm respectively. It is used to control the follow-up movement of the elbow joint suspension point of the space robot arm and the end suspension point of the forearm;

[0013] The constant tension component uses a motor to actively control the reeling and unreeling and to control the suspension force to be relatively constant, so that the suspension point can adapt to the position change in the vertical direction during the deployment of the space robot arm, and the suspension component is connected below;

[0014] The suspension assembly unloads the gravity of each part of the space robot arm during movement and eliminates the additional interference torque generated by the suspension force.

[0015] Furthermore, the following motion control of the mechanical swing arm A is divided into three levels. In the first level, the overall position is controlled by the omnidirectional mobile platform to follow the movement of the six-degree-of-freedom table; the second level is a two-dimensional motion composed of rotation and linear motion formed by the rotary arm, linear module A and beam, and the two-dimensional control mechanism of the hanging point at the end of the swing arm A controls the movement of the six-degree-of-freedom table more quickly and accurately, eliminating the following motion error of the omnidirectional mobile platform; in the third level, the linear drive module B and the linear drive module C form two groups of two-dimensional motion mechanisms on the left and right, each controlling the two hanging points of the mechanical swing arm A to follow the movement of the root hanging points of the two spatial robotic arms on the six-degree-of-freedom table.

[0016] Furthermore, the mechanical swing arm A includes a fixed cantilever, a slewing joint, a slewing direct drive motor, a slewing arm, a linear drive module A, a crossbeam, a lateral roller, a linear drive module B, a linear drive module C and a suspension adapter A. The mechanical swing arm A moves as a whole with the omnidirectional mobile platform. The fixed cantilever is connected to the slewing arm through a slewing joint. The slewing shaft is driven by a direct drive motor. A linear drive module A is installed under the slewing arm. The linear module A is composed of a ball linear guide and a lead screw to form a linear motion pair. The linear module A slide is connected to the crossbeam. The crossbeam has a symmetrical structure. Two sets of rollers are installed in the middle of the crossbeam. The rollers are in contact with the two sides of the slewing arm and have a certain preload force. Two sets of linear drive modules B are symmetrically installed at the lower end of the crossbeam. The slide of each linear drive module B is installed with a linear drive module C. The linear modules B and C are installed in a normal direction.

[0017] Further, the mechanical swing arm B includes a fixed seat, a large swing arm rotary direct drive motor, a large swing arm rotary joint, a large swing arm, a large swing linear motor, a large swing linear module, a small swing rotary direct drive motor, a small swing rotary joint, a small swing arm, a small swing linear module, a small swing linear module drive motor and a suspension adapter B;

[0018] Among them, the fixed seat is installed on the mechanical swing arm bracket, and the mechanical swing arm B moves as a whole with the omnidirectional mobile platform. The fixed seat is connected to the large swing arm through a slewing joint, and the slewing axis is driven by a direct drive motor. A large pendulum linear module is installed on the inner side of the large swing arm, which is composed of a ball linear guide and a lead screw to form a linear motion pair. The large pendulum linear module slide is connected to the small pendulum slewing joint. The upper end of the slewing joint is connected to the small pendulum slewing direct drive motor for driving the slewing joint shaft to rotate. The output shaft at the lower end of the slewing joint is connected to the small swing arm. Two sets of small pendulum linear modules are installed on the bottom of the lower swing arm. The small pendulum linear module slide is installed with a suspension adapter B, which is used to install a constant force device and a suspension assembly. Its positions correspond to the positions of the elbow hanging point of the space robot arm and the end hanging point of the forearm.

[0019] Furthermore, the suspension components are divided into three groups, namely, the suspension at the root of the upper arm, corresponding to the suspension point a of the space manipulator; the suspension at the elbow, corresponding to the suspension point b of the space manipulator; the suspension at the end of the forearm, corresponding to the suspension points c, d, and e of the space manipulator. The three groups of suspension components together constitute a multi-point suspension system. The gravity of each part of the space manipulator from the root joint of the upper arm to the execution joint part of the end of the manipulator is fully unloaded during the movement, and the additional interference torque generated by the suspension force is eliminated.

[0020] Furthermore, the suspension part at the root of the big arm includes a roll connection ring A; a pitch connection axis; an L-shaped long suspension rod; a pin A; a yaw connection axis A; a pin B and a suspension rope composition A, wherein the roll connection ring A is connected to the space manipulator and rolls and rotates around the space manipulator.

[0021] The roll connection ring, the pitch connection axis, and the yaw connection axis form three orthogonal rotation axes, and the suspension at the root of the boom and the space manipulator form a universal connection mechanism;

[0022] The L-shaped long suspension rod allows the suspension parts at the root of the boom to avoid other mechanisms when the space robot arm is in a folded state, so that the suspension point is always located at the center axis of the boom.

[0023] Furthermore, the rolling connection ring A includes a roller, an outer rolling ring and an inner fixed ring. The inner ring surface of the inner fixed ring is tightly connected and fixed to the space robot arm, and the outer ring surface is processed with a rolling groove for the roller. The outer rolling ring is assembled into a whole ring by two half rings and is evenly installed with multiple rollers. After assembly, the roller can roll and rotate in the annular groove of the inner fixed ring.

[0024] Furthermore, the elbow suspension comprises a roll connection ring B, a pitch connection axis B, a U-shaped lifting claw, a short rod, a pin C, a transverse connecting rod, a pin D, a yaw connection axis B and a suspension rope component B; the elbow suspension makes the suspension point located at the center of the rotation axis of the elbow joint, and adopts two symmetrically arranged roll connection rings to be fixed on both sides of the elbow joint, and forms a parallel four-bar linkage mechanism with the U-shaped lifting claw, the transverse connecting rod and the pin D, and the suspension point located in the middle of the transverse connecting rod is always located at the center of the rotation axis of the elbow joint.

[0025] Furthermore, the suspension at the end of the jib includes three suspension points, and the roll connection ring C, the pitch connection axis C, the U-shaped long lifting claw, the deflection pin and the short rod constitute the jib suspension mechanism, that is, the suspension point c suspension mechanism, which has three degrees of freedom of roll, pitch and deflection, so that the jib suspension mechanism is subjected to a constant vertical suspension force equal to the required unloading gravity;

[0026] The deflection connecting shaft D, the pin shaft H, the long horizontal connecting rod 4, the pin shaft I, the short rod, the U-shaped hanging claw, the pitch connecting pin shaft and the rolling connecting ring D constitute the wrist joint suspension mechanism, that is, the suspension point d suspension mechanism, whose suspension force is the wrist joint gravity, and two sets of rolling connecting rings, U-shaped hanging claws and the horizontal connecting rods are used to form a parallel four-bar linkage mechanism to ensure that its suspension point is always located at the center of the wrist joint rotation axis, and is connected to the special-shaped horizontal connecting rod through the pin shaft G;

[0027] The L-shaped short suspension rod, pin K, connecting plate, roll connection ring E, long transverse connecting rod and balance block constitute the end actuator joint suspension mechanism, that is, the suspension point e suspension mechanism, whose suspension force is the gravity of the end actuator joint. Two sets of roll connection rings are symmetrically connected and fixed on both sides of the end actuator joint rotation axis, and are connected as a whole with a connecting plate. The center of the connecting plate is connected to the L-shaped short suspension rod through a pin, and the upper end of the L-shaped short suspension rod is connected to the long transverse connecting rod through a pin J. Its suspension force is located at one end of the long transverse connecting rod pin J, which is above the center of the end actuator joint. The suspension force is balanced by the balance block to ensure the torque balance at the pin H of the long transverse connecting rod.

[0028] Compared with the prior art, the present invention has the following advantages and positive effects.

[0029] 1. The present invention designs an active follow-up mechanical swing arm and multi-point suspension assembly, which controls the positions of the suspension points of the space manipulator to follow the target movement by constructing a set of mechanical swing arm systems that can actively control and respond quickly. The specially designed multi-point suspension structure is used to fully unload the gravity of the space manipulator and the gravity of multiple joints of the manipulator, thereby eliminating the effect of the manipulator's own gravity on the attitude of the spacecraft when the manipulator is deployed, while retaining more degrees of freedom and range of motion of the manipulator, and adapting to a larger range of deployment of the space manipulator;

[0030] 2. The space robot arm is installed on a six-degree-of-freedom simulation platform. The space robot arm is deployed to perform actions such as target capture. The six-degree-of-freedom platform simulates the motion posture of the spacecraft in real time during the space robot arm capture experiment. The omnidirectional mobile platform, counterweight and mechanical swing arm bracket in the device form a mechanical swing arm installation platform that actively follows the movement of the six-degree-of-freedom platform. The target point on the six-degree-of-freedom platform is measured in real time by the camera on the mechanical swing arm bracket to obtain the position and posture changes of the six-degree-of-freedom platform, and then the omnidirectional mobile platform is controlled to follow the movement of the six-degree-of-freedom platform, so that the omnidirectional mobile platform always follows a fixed relative position behind the six-degree-of-freedom platform, so that the mechanical swing arm can maintain a constant relative position with the space robot arm. Taking into account the large load and high control difficulty of the omnidirectional mobile platform, in order to improve the real-time following dynamic characteristics of the omnidirectional mobile platform, a certain error range is allowed for its following movement. This error is corrected and compensated by the movement of the mechanical swing arm with higher motion accuracy and dynamic motion performance to ensure motion accuracy.

[0031] 3. This application is a brand-new microgravity simulation device for space target capture, derotation and other experiments on the ground. Compared with previous experiments of this type, this application performs gravity unloading of multiple suspension points on the space robot arm, so that during the test, the space robot arm can move in a larger range while eliminating the influence of its gravity on the spacecraft attitude simulation, making the test process more realistic and accurate;

[0032] 4. The mechanical swing arm adopts high-performance direct-drive motor, high-precision transmission system, accurate position feedback and lightweight structure design, so that the mechanical swing arm has high dynamic response capability and motion position accuracy, so as to achieve precise dynamic control of the lifting point position.

[0033] 5. The suspension assembly of the present application realizes gravity unloading of the space robot and a larger range of space movement, and adopts a constant force device to control the constant suspension force of each suspension point. During the movement of the space robot, the motor in the constant force device controls the retraction and release of the suspension rope and keeps the required suspension force stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0035] Figure 1-A It is a side view of the space manipulator suspension microgravity simulation device of the present invention;

[0036] Figure 1-B It is a top view of the space manipulator suspension microgravity simulation device of the present invention;

[0037] Figure 2 It is a schematic structural diagram of the mechanical swing arm A of the present invention;

[0038] Figure 3-A It is a schematic structural diagram of a side view of a mechanical swing arm B of the present invention;

[0039] Figure 3-B It is a schematic diagram of the structure of the mechanical swing arm B of the present invention when viewed from above;

[0040] Figure 3-C is a cross-sectional view of the mechanical swing arm B of the present invention;

[0041] Figure 4-A It is a side view of the suspension assembly of the present invention and the corresponding space robot arm suspension position;

[0042] Figure 4-B It is a structural schematic diagram of the suspension assembly of the present invention and the corresponding suspension position of the space robot arm;

[0043] Figure 5-A This is a diagram of the suspension member at the root of the boom of the present invention;

[0044] Figure 5-B It is a partial enlarged view of the lower end of the suspension member at the root of the boom of the present invention;

[0045] Figure 6 It is a diagram of the elbow suspension of the present invention;

[0046] Figure 7 It is a diagram of the suspension member at the end of the forearm of the present invention;

[0047] Figure 8 It is a force analysis diagram of the space manipulator of the present invention;

[0048] Fig. 9 It is a schematic diagram of the space robot arm of the present invention when the small arm rod rotates to form a certain angle with the large arm rod;

[0049] Fig.10 It is a schematic structural diagram of the space manipulator of the present invention;

[0050] Fig.11 It is a structural schematic diagram of the space manipulator suspension microgravity simulation method of the present invention. Description of the drawings:

[0052] 1. Omnidirectional mobile platform; 2. Counterweight; 3. Mechanical swing arm bracket; 4. Camera; 5. Mechanical swing arm A; 6. Mechanical swing arm B; 7. Constant tension component; 8. Suspension component; 9. Space robot arm; 10. Six-degree-of-freedom platform; 5-1. Fixed cantilever; 5-2. Rotary joint; 5-3. Rotary direct drive motor; 5-4. Rotary arm; 5-5. Linear drive module A; 5-6. Crossbeam; 5-7. Lateral roller; 5-8. Linear drive module B; 5-9. Linear drive module C; 5-10. Suspension adapter A; 6-1. Fixed seat; 6-2. Large swing arm rotary direct drive motor; 6-3. Large swing arm rotary joint; 6-4. Large swing arm; 6-5, large pendulum linear motor; 6-6, large pendulum linear module; 6-7, small pendulum rotary direct drive motor; 6-8, small pendulum rotary joint; 6-9, small pendulum arm; 6-10, small pendulum linear module; 6-11, small pendulum linear motor; 6-12, suspension adapter B; 8-1, large arm root suspension; 8-2, elbow suspension; 8-3, small arm end suspension; 8-1-1, rolling connection ring A; 8-1-2, pitch connection axis A; 8-1-3, L-shaped long suspension rod; 8-1-4, pin A; 8-1-5, yaw connection axis A; 8-1-6, pin B; 8-1-7, suspension rope assembly A; 8-1-1a, roller; 8-1-1b, outer rolling ring; 8-1-1c, inner fixed ring; 8-2-1, rolling connection ring B; 8-2-2, pitch connection axis B; 8-2-3, U-shaped lifting claw; 8-2-4, short rod; 8-2-5, pin C; 8-2-6, horizontal connecting rod; 8-2-7, pin D; 8-2-8, yaw connection axis B; 8-2-9, suspension rope assembly B; 8-3-1, rolling connection ring C; 8-3-2, pitch connection axis C; 8-3-3, U-shaped long lifting claw; 8-3-4, yaw pin; 8-3-5, short rod; 8-3-6, pin E; 8-3-7, special-shaped horizontal connecting rod; 8-3-8, pin F; 8-3-9, deflection connecting axis C; 8-3-10, pin G; 8-3-11, deflection connecting axis D; 8-3-12, pin H; 8-3-13, long horizontal connecting rod; 8-3-14, pin I; 8-3-15, short rod; 8-3-16, U-shaped lifting claw; 8-3-17, pitch connection pin; 8-3-18, roll connection ring D; 8-3-19, pin J; 8-3-20, L-shaped short lifting rod; 8-3-21, pin K; 8-3-22, connecting plate; 8-3-23, roll connection ring E; 8-3-24, balance block; 8-3-25, lifting rope component C; 9-1, shoulder roll joint; 9-2, shoulder pitch joint; 9-3 shoulder deflection joint; 9-4, upper arm rod; 9-5, elbow joint; 9-6, lower arm rod; 9-7, wrist deflection joint; 9-8, wrist roll joint; 9-9, terminal execution joint. DETAILED DESCRIPTION

[0053] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0054] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate relative positions or positional relationships, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0055] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0056] The specific embodiments of the present invention are described in detail below.

[0057] The principle on which the present invention solves the technical problem is:

[0058] Regarding the microgravity simulation of the robotic arm in the space target capture test, the space robotic arm has the following technical problems: (1) The space robotic arm changes its position and attitude as it follows the movement and attitude changes of the six-degree-of-freedom simulation platform; (2) The space robotic arm has many motion joints and a large deployment range; (3) In the space robotic arm capture test, it is necessary to simulate as realistically as possible the effect of the torque generated by the robotic arm movement during the deployment process on the six-degree-of-freedom platform, and to fully unload the effect of the space robotic arm's own gravity on the six-degree-of-freedom platform.

[0059] like Figure 1-A and Figure 1-BAs shown, the space robot arm suspension microgravity simulation device includes an omnidirectional mobile platform 1, a counterweight 2, a mechanical swing arm bracket 3, a camera 4, a mechanical swing arm A5, a mechanical swing arm B6, a constant tension component 7, a suspension component 8 and a six-degree-of-freedom platform 10, which is used for microgravity simulation test of a space robot arm 9, and the six-degree-of-freedom platform is arranged on an air floating platform; the camera 4 measures the target point on the six-degree-of-freedom platform in real time, obtains the position and posture change of the six-degree-of-freedom platform, and then controls the mechanical swing arm installation platform to follow the movement of the six-degree-of-freedom platform through the control system; the mechanical swing arm installation platform includes an omnidirectional mobile platform 1, a counterweight 2 and a mechanical swing arm bracket 3, and the omnidirectional mobile platform 1 moves omnidirectionally in a plane; the counterweight 2 is used to balance the overall center of mass of the omnidirectional mobile platform 1 and the mechanical swing arm; the mechanical swing arm bracket 3, whose movement is used to compensate for the movement accuracy of the full mobile platform; the camera 4 is installed on the mechanical swing arm bracket 3, and the space robot arm 9 is arranged at the lower end of the mechanical swing arm bracket 3.

[0060] Preferably, the omnidirectional mobile platform 1: the main body is an AGV vehicle, and the AGV vehicle is omnidirectionally movable in a plane through four Mecanum wheels. In order to achieve large loads and faster response capabilities, an air cushion is used to support the AGV vehicle, and the four Mecanum wheels maintain a certain supporting force through suspension and the air-floating table. During the experiment, since most of the weight is supported by the air cushion, the AGV vehicle can move more smoothly. The top of the AGV vehicle is a load table, on which an interface is processed to connect with the mechanical swing arm bracket 3.

[0061] Preferably, the counterweight 2: The counterweight 2 is made of multiple layers of steel plates stacked on the bottom frame of the mechanical swing arm bracket 3, and is used to balance the overall center of mass of the omnidirectional mobile platform 1 and the mechanical swing arm to ensure smooth overall movement and prevent overturning.

[0062] Preferably, the mechanical swing arm bracket 3: the mechanical swing arm bracket 3 is composed of three-layer frames screwed together, from bottom to top, they are a bottom frame, a height adaptation frame and a swing arm connecting bracket, the bottom of the bottom frame is connected to the table top of the omnidirectional mobile platform 1 by bolts and adjustment washers, the adjustment washers are used for leveling the mechanical swing arm bracket 3, the front section of the top of the bottom frame is connected to the height adaptation frame, and a counterweight 2 plate is installed at the rear end, the swing arm connecting bracket is installed on the top surface of the height adaptation frame, and the installation surface connected to the mechanical swing arm is suspended forward a certain distance, so that the installation position of the mechanical swing arm is as close as possible to the space robot arm 9, and two cameras 4 are installed at the lower end of the swing arm connecting surface for measuring the position and posture of the six-degree-of-freedom platform.

[0063] Preferably, camera 4: camera 4 is used to measure the position and posture of the target point, wherein two cameras 4 are installed at the lower end of the swing arm connecting surface in the mechanical swing arm bracket 3 to measure the position and posture of the omnidirectional mobile platform 1 relative to the six-degree-of-freedom platform relative to the omnidirectional mobile platform 1, and the camera 4 is installed on the mechanical swing arm to measure the position and posture of the space robot arm 9 relative to the mechanical swing arm.

[0064] Preferably, the mechanical swing arm A5: the mechanical swing arm A5 is installed on the mechanical swing arm bracket 3, located between the two mechanical swing arms B6, and is used to control the follow-up movement of the suspension point at the root of the upper arm of the space robot 9. Figure 2 As shown, the basic components of the mechanical swing arm A5 include: a fixed cantilever 5-1, a swivel joint 5-2, a swivel direct drive motor 5-3, a swivel arm 5-4, a linear drive module A5-5, a crossbeam 5-6, a lateral roller 5-7, a linear drive module B5-8, a linear drive module C5-9 and a suspension adapter A5-10.

[0065] Among them, the fixed cantilever 5-1 is installed on the mechanical swing arm bracket 3, and the mechanical swing arm A5 moves as a whole with the omnidirectional mobile platform 1. The fixed cantilever 5-1 is connected to the slewing arm 5-4 through a slewing joint 5-2. The slewing joint 5-2 is composed of a precision-machined shaft and a high-precision bearing assembly to ensure the mechanical accuracy of the slewing motion. The slewing shaft is driven by a direct drive motor. The direct drive motor integrates a high-precision encoder as feedback to ensure the control accuracy of the rotation. A linear drive module A5-5 is installed under the slewing arm 5-4. The linear module A consists of a linear motion pair composed of a ball linear guide and a lead screw. The lead screw is driven by a motor with an integrated high-precision absolute encoder to realize the linear motion of the linear module slide. The linear transmission is calibrated and compensated to ensure sufficient transmission accuracy. The slide of linear module A is connected to beam 5-6. Beam 5-6 has a symmetrical structure. Two sets of rollers are installed in the middle of beam 5-6. The rollers are in contact with the two sides of the slewing arm 5-4 and have a certain preload force, which serves as a roll protection for beam 5-6 during linear motion. Two sets of linear drive modules B5-8 are symmetrically installed at the lower end of beam 5-6. Each slide of linear drive module B5-8 is installed with linear drive module C5-9. Linear modules B and C are installed in a normal direction. Their structure is similar to that of linear drive module A5-5. They are composed of a linear motion pair consisting of a ball linear guide and a lead screw. The lead screw is driven by a motor with an integrated high-precision absolute encoder to realize the linear motion of the linear module slide. The linear transmission is calibrated and compensated to ensure sufficient transmission accuracy. A suspension adapter A5-10 is installed on the slide of the linear drive module C5-9. The suspension adapter A5-10 is used to install the constant force device and the suspension assembly 8, and its position corresponds to the position of the suspension point at the root of the main arm of the space robot 9.

[0066] The following motion control of the mechanical swing arm A5 is divided into three levels. In the first level, the overall position is controlled by the omnidirectional mobile platform 1 to follow the movement of the six-degree-of-freedom platform; the second level is a two-dimensional motion composed of rotation and linear motion formed by the rotating arm 5-4, the linear module A and the beam 5-6, which controls the two-dimensional control mechanism of the suspension point at the end of the swing arm A to follow the movement of the six-degree-of-freedom platform more quickly and accurately, eliminating the following motion error of the omnidirectional mobile platform 1; in the third level, the linear drive module B5-8 and the linear drive module C5-9 form two groups of two-dimensional motion mechanisms on the left and right, respectively controlling the two suspension points of the mechanical swing arm A5 to follow the movement of the root suspension points of the two spatial mechanical arms 9 on the six-degree-of-freedom platform.

[0067] Preferably, mechanical swing arm B6: The mechanical swing arm B6 has two sets, which are symmetrical structures, and are symmetrically installed on the mechanical swing arm bracket 3 on the left and right, corresponding to a space robot arm 9 respectively. It is used to control the follow-up movement of the elbow joint suspension point and the end suspension point of the forearm of the space robot arm 9. As shown in Figure 3, the basic components of the mechanical swing arm B6 include: a fixed seat, a large swing arm rotary direct drive motor 5-3, a large swing arm rotary joint 5-2, a large swing arm, a large swing linear motor, a large swing linear module, a small swing rotary direct drive motor 5-3, a small swing rotary joint 5-2, a small swing arm, a small swing linear module, a small swing linear module drive motor and a suspension adapter B.

[0068] Among them, the fixed seat is installed on the mechanical swing arm bracket 3, and the mechanical swing arm B6 moves as a whole with the omnidirectional mobile platform 1. The fixed seat is connected to the large swing arm through a slewing joint 5-2. The slewing joint 5-2 is composed of a precision-machined shaft and a high-precision bearing assembly to ensure the mechanical accuracy of the slewing motion. The slewing shaft is driven by a direct drive motor. The direct drive motor integrates a high-precision encoder as feedback to ensure the control accuracy of the rotation. A large pendulum linear module is installed on the inside of the large swing arm. The linear motion pair is composed of a ball linear guide and a lead screw. The lead screw is driven by a motor with an integrated high-precision absolute encoder to realize the linear motion of the linear module slide. The linear transmission is calibrated and compensated to ensure sufficient transmission accuracy. The large pendulum linear module slide is connected to the small pendulum slewing joint 5-2. The upper end of the slewing joint 5-2 is connected to the small pendulum slewing direct drive motor 5-3 for driving the slewing joint 5-2 axis to rotate. The output shaft at the lower end of the slewing joint 5-2 is connected to the small swing arm. Two sets of small pendulum linear modules are installed on the bottom surface of the lower swing arm, which are driven by a motor with a precision feedback encoder. The small pendulum linear module slide is installed with a suspension adapter B, which is used to install the constant force device and the suspension assembly 8, and its position corresponds to the elbow suspension point of the space robot arm 9 and the end suspension point of the forearm.

[0069] Preferably, the constant tension component 7: the constant tension component 7 uses a motor to actively control the winding and unwinding of the winding wire and control the suspension force to be relatively constant, so that the suspension point can adapt to the position change in the vertical direction during the deployment of the space robot 9. The constant tension component 7 is installed on the suspension adapter and is connected to the suspension component 8 at the bottom.

[0070] Preferably, a multi-point suspension component: the suspension component is connected to the space manipulator. Three groups of suspension components are designed in this paper, as shown in Figure 4, namely the suspension at the root of the upper arm, corresponding to the suspension point a of the space manipulator; the elbow suspension, corresponding to the suspension point b of the space manipulator; the suspension at the end of the forearm, corresponding to the suspension points c, d, and e of the space manipulator. The three groups of suspension components together constitute a multi-point suspension system, which actually realizes 5 suspension points. After calculating and distributing the suspension force of each suspension point, the gravity of the space manipulator from the root joint of the upper arm to the execution joint part of the end of the manipulator is fully unloaded during the movement, and the additional interference torque generated by the suspension force is eliminated.

[0071] The suspension part 8-1 at the root of the boom is shown in Figure 5, including a roll connection ring A8-1-1; a pitch connection axis A8-1-2; an L-shaped long suspension rod 8-1-3; a pin A8-1-4; a yaw connection axis A8-1-5; a pin B8-1-6 and a suspension rope composition A8-1-7, wherein the roll connection ring is connected to the space robot arm and can roll and rotate around the arm of the robot arm, and its composition includes a roller 8-1-1a, an outer roll ring 8-1-1b and an inner fixed ring 8-1-1c.

[0072] The connection between the multi-point suspension assembly and the space manipulator adopts this structure. The inner ring surface of the inner fixed ring 8-1-1c holds the space manipulator tightly and connects and fixes it. The outer ring surface is processed with the rolling groove of the roller 8-1-1a. The outer rolling ring 8-1-1b is assembled into a whole ring by two half rings and evenly installed with four rollers 8-1-1a. After assembly, the roller 8-1-1a can roll and rotate in the annular groove of the inner fixed ring 8-1-1c. The rolling connection ring and the pitch connection axis and the deflection connection axis form three orthogonal rotation axes, so that the suspension part at the root of the boom and the space manipulator form a universal connection mechanism, so that the suspension assembly can adapt to the deflection, pitch, and roll of the manipulator. The L-shaped long suspension rod 8-1-3 can make the suspension part at the root of the boom avoid other mechanisms when the space manipulator is in the folded state, so that the suspension point is always located at the center axis position of the arm.

[0073] Elbow suspension Figure 6 As shown, it includes a roll connection ring B8-2-1, a pitch connection axis B8-2-2, a U-shaped lifting claw 8-2-3, a short rod 8-2-4, a pin C8-2-5, a transverse connecting rod 8-2-6, a pin D8-2-7, a deflection connection axis B8-2-8 and a suspension rope B8-2-9; in order to make the suspension point located at the center of the rotation axis of the elbow joint, the elbow suspension adopts two symmetrically arranged roll connection rings fixed on both sides of the elbow joint, and together with the U-shaped lifting claw 8-2-3, the transverse connecting rod 8-2-6 and the pin, a parallel four-bar linkage is formed, so that when the space manipulator undergoes deflection, pitch and other movements, the suspension point located in the middle of the transverse connecting rod 8-2-6 is always located at the center of the rotation axis of the elbow joint.

[0074] The suspension at the end of the forearm is relatively complex, integrating three suspension points, such as Figure 7 As shown, rolling connecting ring C8-3-1, pitch connecting axis C8-3-2, U-shaped long lifting claw 8-3-3, deflection pin 8-3-4, short rod 8-3-158-3-5, pin E8-3-6, special-shaped transverse connecting rod 8-3-7, pin F8-3-8, deflection connecting axis C8-3-9, pin G8-3-10, deflection connecting axis D8-3-11, pin H8-3-12, long transverse connecting rod 8-3 -134, pin I8-3-14, short rod 8-3-158-3-5, U-shaped lifting claw 8-3-16, pitch connecting pin 8-3-17, roll connecting ring D8-3-18, pin J8-3-19, L-shaped short lifting rod 8-3-20, pin K8-3-21, connecting plate 8-3-22, roll connecting ring E8-3-23, balance block 8-3-24 and lifting rope composition C8-3-25.

[0075] Among them: the roll connecting ring C8-3-1, the pitch connecting axis C8-3-2, the U-shaped long lifting claw 8-3-3, the deflection pin 8-3-4 and the short rod 8-3-158-3-5 constitute the forearm suspension mechanism, that is, the suspension point c suspension mechanism, which has three degrees of freedom of roll, pitch and deflection, and is connected through the pin E8-3-6 and the special-shaped cross link 8-3-7. By calculating and distributing the position of the pin F8-3-8 on the special-shaped cross link 8-3-7, the forearm suspension mechanism is subjected to a constant vertical suspension force equal to the required unloading gravity.

[0076] Among them: the deflection connecting axis D8-3-11, the pin H8-3-12, the long transverse connecting rod 8-3-134, the pin I8-3-14, the short rod 8-3-158-3-5, the U-shaped lifting claw 8-3-16, the pitch connecting pin 8-3-17 and the rolling connecting ring D8-3-18 constitute the wrist joint suspension mechanism, that is, the suspension point d suspension mechanism, whose suspension force is the wrist joint gravity, and its structure is similar to the elbow suspension. Two sets of rolling connecting rings, U-shaped lifting claws 8-3-16 and the transverse connecting rods are used to form a parallel four-bar linkage mechanism to ensure that its suspension point is always located at the center of the wrist joint rotation axis, and is connected to the special-shaped transverse connecting rod 8-3-7 through the pin G8-3-10.

[0077] Among them: L-shaped short suspension rod 8-3-20, pin K8-3-21, connecting plate 8-3-22, rolling connecting ring E8-3-23, long horizontal connecting rod 8-3-13 and balancing block 8-3-24 constitute the end actuator joint suspension mechanism, that is, the suspension point e suspension mechanism, whose suspension force is the gravity of the end actuator joint, and the structure uses two sets of rolling connecting rings symmetrically connected and fixed on both sides of the end actuator joint shaft, and connected as a whole with connecting plate 8-3-22, the center of connecting plate 8-3-22 is connected to L-shaped short suspension rod 8-3-20 through pin, and the upper end of L-shaped short suspension rod 8-3-20 is connected to long horizontal connecting rod 8-3-13 through pin J8-3-19. The suspension force is located at one end of the pin J8-3-19 of the long horizontal link 8-3-13, and is always above the center of the end actuator joint. The suspension force is balanced by the balance block 8-3-24, so that the torque at the pin H8-3-12 of the long horizontal link 8-3-13 is balanced.

[0078] The space manipulator that needs to unload gravity is simplified as follows Figure 8 The joint and arm structure of uniform mass is shown. The mass of the root joint, elbow joint, and wrist deflection joint is 6kg, the weight of the forearm end deflection joint and the end execution joint is 3kg, and the weight of the upper arm and lower arm is 10kg. The distance between the root and the elbow is 1060mm, the distance between the elbow and the wrist deflection joint is 1060mm, and the distance between the wrist and the end execution joint is 180mm. The root suspension point force of the upper arm is F1, which is located 100mm away from the root joint; the elbow suspension point force is F2; ​​the forearm end suspension point force is F3, which is located 725mm away from the elbow joint; the wrist suspension point force is F4; and the end execution joint suspension point force is F5. The balance block is 113mm away from the wrist suspension point, and the gravity is G1. Then the wrist suspension point and the end suspension point have a combined suspension point force Fa=F4+F5+G1, which is located above the center of the wrist deflection joint; the forearm end suspension point F3 and Fa are combined into a suspension point Fb through a special-shaped horizontal connecting rod mechanism, and the Fb suspension point is correspondingly connected to the small swing arm suspension point of the mechanical swing arm B.

[0079] According to the gravity unloading requirements, it is easy to know that F5 = 3kgf, F4 = 6kgf;

[0080] According to the moment balance at Fa, we have:

[0081] Then: Fa = F4 + F5 + G1 = 13.78 kgf;

[0082] F3 unloads the forearm and the forearm end execution joint gravity, considering the elbow moment balance, we have:

[0083]

[0084] Calculated F3 = 11.697 kgf, then Fb = F3 + Fa = 25.46 kgf;

[0085] In order to balance the moment at Fb, let the distance between F3 and Fb be x, and the distance between Fa and Fb be y, then:

[0086]

[0087] By calculating x=181.2mm, y=153.8mm, the position of Fb can be determined.

[0088] And F1+F2+F3=6+10+6+10+3 (kgf), which is the sum of the gravity of the root joint, upper arm, elbow joint, forearm and the deflection joint at the end of the forearm.

[0089] And the root moment is 0, then:

[0090] F1×100+F2×1060+F3×(1060+725) =10×530+6×1060+10×(1060+530)+3×(1060+1060)

[0091] Calculation shows that F1=12.146kgf, F2=11.158kgf.

[0092] Substituting the calculated values ​​of F1, F2, and F3 into the calculated torque at the elbow joint, we have:

[0093] F1×960+10×530+3×1060=F3×725+10×530+6×1060=20140kgf·mm

[0094] It can be seen that at this time, there is no additional torque generated by gravity and suspension force at the elbow joint of the space manipulator, and the gravity at various parts of the space manipulator is relatively fully unloaded.

[0095] When the small arm of the robot arm rotates to form a certain angle with the large arm, such as Fig. 9 As shown in the figure, the root joint is taken as the origin, the direction of the upper arm is taken as the x-axis, the vertical direction is taken as the z-axis, and the angle between the forearm and the upper arm is α.

[0096] It is easy to get the torque about the x-axis:

[0097] Mx=F3×725×sinα-(10×530×sinα+3×1060×sinα) =sinα[F3×725-(10×530+3×1060)]=0

[0098] The torque about the y-axis is:

[0099] My=F1×100+F2×1060+F3×(1060+725×cosα) -[10×530+6×1060+10×(1060+530×cosα)+3 ×(1060+1060×cosα)]

[0100] =F1×100+F2×1060+F3×1060 -(10×530+6×1060+10×1060+3×1060)+cosα×[F3×725-(10×530+3×1060)]

[0101] =F1×100+F2×1060+F3×1060 -(10×530+6×1060+10×1060+3×1060)

[0102] It can be seen that at this time, the torque of the spatial robot arm in the y-axis direction of the root is independent of the rotation angle of the small arm rod. After substituting F1, F2, and F3, it is calculated that My=0.

[0103] During the movement of the space manipulator, the suspension force and gravity are always in a state of torque balance at all parts of the manipulator, and no additional interference torque will be generated.

[0104] More preferably, the space manipulator is the main execution device for the target capture test, and two manipulators are symmetrically mounted on the simulation wall of the six-degree-of-freedom platform. Fig.10 As shown, it includes a shoulder roll joint 9-1, a shoulder pitch joint 9-2, a shoulder deflection joint, an upper arm lever, an elbow joint, a lower arm lever, a wrist deflection joint, a wrist roll joint and an end execution joint, wherein the shoulder roll joint 9-1, the shoulder pitch joint 9-2 and the shoulder deflection joint stroke root joint.

[0105] Gravity unloading is for the moving parts, namely, the shoulder deflection joint 9-3, the upper arm bar 9-4, the elbow joint 9-5, the lower arm bar 9-6, the wrist deflection joint 9-7, the wrist roll joint 9-8 and the end execution joint 9-9. In this microgravity system, the shoulder joint of the space manipulator can realize deflection and pitching during the test. Under the condition that there is no obstacle avoidance requirement in the test environment, the space manipulator can cover the required three-dimensional space for the test. The space manipulator is generally designed with redundant degrees of freedom for obstacle avoidance, etc. During the test, limiting the shoulder roll joint 9-1 can greatly reduce the structural complexity of the microgravity suspension simulation device, so that the test can be realized in engineering.

[0106] When the robot arm is stretched forward, the shoulder roll joint 9-1 can be rolled 90 degrees in the state of the device being suspended, and then the shoulder roll joint 9-1 is fixed, and the original yaw joint of the space robot arm becomes a pitch joint, and the original pitch joint becomes a yaw joint. At this time, the space robot arm can perform a certain range of pitch and yaw movements in this posture. In this state, the space robot arm will generate a certain axial deflection torque of the big arm rod 9-4 at the installation point on the six-degree-of-freedom platform, and it is necessary to adjust the elbow suspension point or add an air-floating follow-up support device of the elbow joint 9-5 to balance the influence of this torque.

[0107] The shoulder roll joint 9-1 and shoulder pitch joint 9-2 of the space robot are fixed on the six-degree-of-freedom platform. During the test, their position and posture relative to the six-degree-of-freedom platform do not change. Their gravity is balanced by the counterweight on the six-degree-of-freedom platform, and there is no need for suspended gravity unloading.

[0108] More preferably, the six-degree-of-freedom platform 10 is a simulation platform for physically simulating the service spacecraft, simulating the linear motion of three degrees of freedom through the plane air bearing below and the constant force cylinder in the vertical direction, simulating the rotation of three degrees of freedom through the air-floating ball bearing above, and simulating the mass characteristics of the spacecraft through structural design. The six-degree-of-freedom platform is equipped with thrusters, gyroscopes and other power and control devices for simulating spacecraft, so as to realize the movement and attitude adjustment control of the six-degree-of-freedom platform during the test.

[0109] In the actual working process, the following steps are followed: S1. Install the space robot arm in a folded state on the six-degree-of-freedom platform, and control the six-degree-of-freedom platform to move to the test starting position on the air-floating platform; S2. Control the movement of the omnidirectional mobile platform to move the microgravity simulation device to a position near the six-degree-of-freedom platform, and adjust the position according to the target point of the six-degree-of-freedom platform; S3. Control the movement of the mechanical swing arm to move the suspension component of the mechanical swing arm to the corresponding suspension point position of the space robot arm, and connect the suspension component to the suspension point; S4. Control the six-degree-of-freedom platform to move to the corresponding position close to the capture target on the air-floating platform, and control the omnidirectional mobile platform to follow the movement of the six-degree-of-freedom platform; S5 , control the space robot to unfold, the order is to unfold the forearm outward first, and then control the linkage between the big arm rod and the small arm rod to make the end execution joint close to the capture target, and at the same time control the mechanical swing arm to follow the movement of the space robot arm, so that the suspension assembly is always kept above the hanging point; S6, after the space robot completes the test, control the movement to the original retracted state, control the mechanical swing arm to follow the movement of the space robot arm, so that the suspension assembly is always kept above the hanging point; S7, after the six-degree-of-freedom table moves to the parking position, turn off the air source and support the fixed six-degree-of-freedom table; S8, disassemble the suspension assembly, move the omnidirectional mobile platform away from the six-degree-of-freedom table to the parking position, turn off the air source power supply, and the test ends.

[0110] The omnidirectional mobile platform supported by an air cushion can actively and stably follow the movement of the six-degree-of-freedom table, ensuring that the microgravity simulation device can always follow the relatively constant position of the space robot arm as a whole; through a mechanical swing arm system that can respond quickly and control, it actively follows the movement of the hanging point on the space robot arm, and controls the suspension assembly to always accurately follow above the hanging point. The mechanical swing arm is divided into two parts, front and rear, for two-level control. The first part is a polar coordinate system composed of the rotational motion of the large swing arm and the linear motion in the length direction of the swing arm, which can more accurately and quickly follow the position changes of the spatial robot arm on the six-degree-of-freedom platform for small-range adjustment, eliminating the error of the omnidirectional mobile platform following; the second level is the position following control of the suspension component. The mechanical swing arm A adopts two-level linear motion to form a two-dimensional movement to control the suspension component at the root of the large arm of the space robot to follow the movement of the hanging point; the mechanical swing arm B uses the rotational motion of the small swing arm and the linear motion in the direction of the small swing arm to form a polar coordinate motion to control the elbow suspension component of the space robot and the end suspension component of the small arm to follow the movement of the hanging point. Each suspension component controls the vertical direction to follow the movement of the hanging point through a constant force device that actively retracts and releases the suspension rope, so that multiple suspension points can follow the space robot to expand.

[0111] By using a suspension component that can adapt to the multi-joint motion of the robotic arm and calculating and distributing the suspension force of each suspension point, the gravity of the moving part of the space robotic arm is fully unloaded, eliminating the influence of gravity on the six-degree-of-freedom platform. A suspension component for performing joint motion at the end of the space robotic arm was invented, which integrates three suspension points into one, and controls the three groups of suspension components to follow the motion through the mechanical swing arm to achieve gravity unloading of five suspension points.

[0112] During the test, the space manipulator began to unfold according to the motion command control, and the mechanical swing arm above was controlled to follow the swing, so that the suspension point on the mechanical swing arm followed the motion trajectory of the corresponding suspension point on the space manipulator. At the same time, the encoders of each joint of the space manipulator fed back the position and torque changes of the space manipulator in real time, and the control ensured that the position of the suspension point of the mechanical swing arm and the suspension point on the space manipulator remained consistent during movement. In addition, the actual suspension point position was calculated by measuring the target point on the space manipulator through the camera on the mechanical swing arm, and the movement of the mechanical swing arm was corrected to eliminate the error of the suspension point position. The error between the actual suspension point on the space manipulator and the suspension point position given by the feedback of the space manipulator itself was caused by two reasons: the position error between the omnidirectional mobile platform and the six-degree-of-freedom platform was caused by the camera measurement error and the motion control accuracy of the omnidirectional mobile platform following the six-degree-of-freedom platform, which would cause a certain deviation error between the position coordinates of the space manipulator and the position coordinates of the mechanical swing arm; the error caused by the flexibility of the space manipulator itself would cause an error between the feedback position of the space manipulator itself and the actual position, and these errors would eventually be reflected in the position error between the suspension point of the mechanical swing arm and the suspension point of the space manipulator.

[0113] In order to more fully unload the gravity of the space manipulator, after analysis, three suspension points are set for each space manipulator on the mechanical swing arm, and the root of the big arm, the elbow joint and the end of the forearm of the space manipulator are suspended by the suspension assembly. The end suspension assembly is designed with a multi-level suspension assembly to suspend the two-level joints at the end, so that the rest of the manipulator except the root joint is suspended, and the root joint is fixed on the simulation wall on the six-degree-of-freedom table. Its gravity is borne by the six-degree-of-freedom table through balancing, so that the gravity of the entire space manipulator is unloaded. The connection between the suspension assembly and the space manipulator is designed as a multi-degree-of-freedom joint, which can adapt to the deployment movement of the manipulator while ensuring the upward suspension force.

[0114] The device provided by this apparatus is a brand-new microgravity simulation device for conducting space target capture, derotation and other experiments on the ground. Compared with previous experiments of this type, this application performs gravity unloading of multiple suspension points on the space robot arm, so that during the test, the space robot arm can be allowed to move in a larger range while eliminating the influence of its gravity on the spacecraft attitude simulation, making the test process more realistic and accurate.

[0115] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A space manipulator suspension microgravity simulation device, characterized in that: It includes a mechanical swing arm mounting platform, a six-degree-of-freedom platform and a camera, wherein the six-degree-of-freedom platform is arranged on an air-floating platform; The camera measures the target point on the six-degree-of-freedom table in real time, obtains the position and posture change of the six-degree-of-freedom table, and then controls the mechanical swing arm mounting platform to follow the movement of the six-degree-of-freedom table through the control system; The mechanical swing arm installation platform includes an omnidirectional mobile platform, a counterweight and a mechanical swing arm bracket, the omnidirectional mobile platform moves omnidirectionally in a plane; the counterweight; Used to balance the overall center of mass of the omnidirectional mobile platform and the mechanical swing arm; the mechanical swing arm bracket, whose movement is used to compensate for the movement accuracy of the full mobile platform; The camera is mounted on the mechanical swing arm bracket, and the mechanical swing arm bracket ensures the precision movement of the space mechanical arm at the lower end relative to the six-free platform through gravity unloading and follow-up components; The gravity unloading and following assembly includes a mechanical swing arm A, a mechanical swing arm B, a constant tension assembly and a suspension assembly. The mechanical swing arm A is installed on the mechanical swing arm bracket and is located between the two mechanical swing arms B, and is used to control the following movement of the suspension point at the root of the space robot arm. The mechanical swing arms B are symmetrically installed on the mechanical swing arm bracket, corresponding to one space robot arm respectively, and are used to control the follow-up movement of the elbow joint suspension point of the space robot arm and the end suspension point of the forearm; The constant tension component uses a motor to actively control the reeling and unreeling and to control the suspension force to be relatively constant, so that the suspension point can adapt to the position change in the vertical direction during the deployment of the space robot arm, and the suspension component is connected below; The suspension assembly unloads the gravity of each part of the space robot arm during movement and eliminates the additional interference torque generated by the suspension force.

2. The space manipulator suspension microgravity simulation device according to claim 1, characterized in that: The following motion control of the mechanical swing arm A is divided into three levels. In the first level, the overall position is controlled by the omnidirectional mobile platform to follow the movement of the six-degree-of-freedom table; the second level is a two-dimensional motion composed of rotation and linear motion formed by the rotary arm, linear module A and beam, and the two-dimensional control mechanism of the hanging point at the end of the swing arm A is controlled to follow the movement of the six-degree-of-freedom table more quickly and accurately, eliminating the following motion error of the omnidirectional mobile platform; in the third level, the linear drive module B and the linear drive module C form two groups of left and right two-dimensional motion mechanisms, each of which controls the two hanging points of the mechanical swing arm A to follow the movement of the root hanging points of the two spatial robotic arms on the six-degree-of-freedom table.

3. The space manipulator suspension microgravity simulation device according to claim 2, characterized in that: Mechanical swing arm A includes a fixed cantilever, a slewing joint, a slewing direct drive motor, a slewing arm, a linear drive module A, a crossbeam, lateral rollers, a linear drive module B, a linear drive module C and a suspension adapter A. The mechanical swing arm A moves as a whole together with the omnidirectional mobile platform. The fixed cantilever is connected to the slewing arm through a slewing joint. The slewing axis is driven by a direct drive motor. A linear drive module A is installed under the slewing arm. The linear module A consists of a ball linear guide and a lead screw to form a linear motion pair. The linear module A slide is connected to the crossbeam. The crossbeam has a symmetrical structure. Two sets of rollers are installed in the middle of the crossbeam. The rollers are in contact with the two sides of the slewing arm and have a certain preload. Two sets of linear drive modules B are symmetrically installed at the lower end of the beam. The slide of each linear drive module B is installed with a linear drive module C, and the linear modules B and C are installed in a normal direction.

4. The space manipulator suspension microgravity simulation device according to claim 1, characterized in that: The mechanical swing arm B includes a fixed seat, a large swing arm rotary direct drive motor, a large swing arm rotary joint, a large swing arm, a large swing linear motor, a large swing linear module, a small swing rotary direct drive motor, a small swing rotary joint, a small swing arm, a small swing linear module, a small swing linear module drive motor and a suspension adapter B; Among them, the fixed seat is installed on the mechanical swing arm bracket, and the mechanical swing arm B moves as a whole with the omnidirectional mobile platform. The fixed seat is connected to the large swing arm through a slewing joint, and the slewing axis is driven by a direct drive motor. A large pendulum linear module is installed on the inner side of the large swing arm, which is composed of a ball linear guide and a lead screw to form a linear motion pair. The large pendulum linear module slide is connected to the small pendulum slewing joint. The upper end of the slewing joint is connected to the small pendulum slewing direct drive motor for driving the slewing joint shaft to rotate. The output shaft at the lower end of the slewing joint is connected to the small swing arm. Two sets of small pendulum linear modules are installed on the bottom of the lower swing arm. The small pendulum linear module slide is installed with a suspension adapter B, which is used to install a constant force device and a suspension assembly. Its positions correspond to the positions of the elbow hanging point of the space robot arm and the end hanging point of the forearm.

5. The space manipulator suspension microgravity simulation device according to claim 1, characterized in that: There are three groups of suspension components, namely, the suspension at the root of the upper arm, which corresponds to the suspension point a of the space manipulator; the suspension at the elbow, which corresponds to the suspension point b of the space manipulator; and the suspension at the end of the forearm, which corresponds to the suspension points c, d, and e of the space manipulator. The three groups of suspension components together constitute a multi-point suspension system. The gravity of each part of the space manipulator from the root joint of the upper arm to the execution joint part of the end of the manipulator is fully unloaded during the movement, and the additional interference torque generated by the suspension force is eliminated.

6. The space manipulator suspension microgravity simulation device according to claim 5, characterized in that: The suspension parts at the root of the big arm include a roll connection ring A; a pitch connection axis; an L-shaped long suspension rod; a pin A; a yaw connection axis A; a pin B and a suspension rope A, wherein the roll connection ring A is connected to the space manipulator and rolls and rotates around the space manipulator. The roll connection ring, the pitch connection axis, and the yaw connection axis form three orthogonal rotation axes, and the suspension at the root of the boom and the space manipulator form a universal connection mechanism; The L-shaped long suspension rod allows the suspension parts at the root of the boom to avoid other mechanisms when the space robot arm is in a folded state, so that the suspension point is always located at the center axis of the boom.

7. The space manipulator suspension microgravity simulation device according to claim 6, characterized in that: The rolling connection ring A includes a roller, an outer rolling ring and an inner fixed ring. The inner ring surface of the inner fixed ring is tightly connected to the space robot arm, and the outer ring surface is processed with a rolling groove for the roller. The outer rolling ring is assembled into a whole ring by two half rings and is evenly installed with multiple rollers. After assembly, the roller can roll and rotate in the annular groove of the inner fixed ring.

8. The space manipulator suspension microgravity simulation device according to claim 7, characterized in that: The elbow suspension comprises a roll connection ring B, a pitch connection axis B, a U-shaped lifting claw, a short rod, a pin C, a transverse connecting rod, a pin D, a yaw connection axis B and a suspension rope component B; the elbow suspension makes the suspension point located at the center of the rotation axis of the elbow joint, and adopts two symmetrically arranged roll connection rings to be fixed on both sides of the elbow joint, and forms a parallel four-bar linkage mechanism with the U-shaped lifting claw, the transverse connecting rod and the pin D. The suspension point located in the middle of the transverse connecting rod is always located at the center of the rotation axis of the elbow joint.

9. The space manipulator suspension microgravity simulation device according to claim 6, characterized in that: The suspension at the end of the jib includes three suspension points. The roll connection ring C, the pitch connection axis C, the U-shaped long lifting claw, the deflection pin and the short rod constitute the jib suspension mechanism, namely the suspension point c suspension mechanism, which has three degrees of freedom of roll, pitch and deflection, so that the jib suspension mechanism is subjected to a constant vertical suspension force equal to the required unloading gravity. The deflection connecting axis D, the pin H, the long horizontal connecting rod, the pin I, the short rod, the U-shaped hanging claw, the pitch connecting pin and the rolling connecting ring D form a wrist joint suspension mechanism, that is, a suspension point d suspension mechanism, whose suspension force is the wrist joint gravity. Two sets of rolling connecting rings, U-shaped hanging claws and the horizontal connecting rod form a parallel four-bar linkage mechanism to ensure that its suspension point is always located at the center of the wrist joint rotation axis and is connected to the special-shaped horizontal connecting rod through the pin G. The L-shaped short suspension rod, pin K, connecting plate, roll connection ring E, long transverse connecting rod and balance block constitute the end actuator joint suspension mechanism, that is, the suspension point e suspension mechanism, whose suspension force is the gravity of the end actuator joint. Two sets of roll connection rings are symmetrically connected and fixed on both sides of the end actuator joint rotation axis, and are connected as a whole with a connecting plate. The center of the connecting plate is connected to the L-shaped short suspension rod through a pin, and the upper end of the L-shaped short suspension rod is connected to the long transverse connecting rod through a pin J. Its suspension force is located at one end of the long transverse connecting rod pin J, which is above the center of the end actuator joint. The suspension force is balanced by the balance block to ensure the torque balance at the pin H of the long transverse connecting rod.

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