CN112520077A

CN112520077A - Space manipulator suspension microgravity simulation method

Info

Publication number: CN112520077A
Application number: CN202011223903.8A
Authority: CN
Inventors: 齐放; 吴跃民; 李博; 朱朝晖
Original assignee: Tianjin Aerospace Electromechanical Equipment Research Institute
Current assignee: Tianjin Aerospace Electromechanical Equipment Research Institute
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-03-19
Anticipated expiration: 2040-11-05
Also published as: CN112520077B

Abstract

The invention provides a space manipulator suspension microgravity simulation method, which belongs to the field of simulation experiments and comprises S1, mounting a space manipulator, and controlling a six-degree-of-freedom platform to move to a test starting position on an air floatation platform; s2, adjusting the alignment position according to the six-degree-of-freedom table target point; s3, controlling the mechanical swing arm to move, and connecting the suspension assembly with the suspension point; s4, controlling the omnidirectional moving platform to move along with the six-degree-of-freedom platform; s5, controlling the space manipulator to unfold; s6, after the space manipulator completes the test, controlling the space manipulator to move to the original folding state; s7, after the six-degree-of-freedom platform moves to the parking position, closing the air source, and supporting and fixing the six-degree-of-freedom platform; and S8, finishing the test of detaching the suspension assembly. The invention eliminates the effect of self gravity on the attitude of the spacecraft when the mechanical arm is unfolded, simultaneously reserves more freedom degrees and motion ranges of the mechanical arm, and adapts to the unfolding range of the space mechanical arm in a larger range.

Description

Space manipulator suspension microgravity simulation method

Technical Field

The invention belongs to the field of simulation experiments, and relates to a space manipulator suspension microgravity simulation method.

Background

The method is a common method in the aerospace field and is a strategy for considering both economy and timeliness in the development process.

In recent years, space manipulators or space robots undertake more and more important tasks in space exploration and development, and can replace astronauts to complete various tasks such as target capture, fault maintenance, garbage cleaning, star catalogue sampling and the like in severe space environments. The space mechanical arm developed based on the space micro-low gravity environment and the application background mostly has the characteristics of long arm rods, multiple degrees of freedom, small motor power and the like, cannot be directly unfolded to work in the ground gravity environment, and needs a micro-gravity simulation device to unload the gravity of the mechanical arm for test verification. The spacecraft which carries out tasks such as capturing, maintaining and detecting adopts two mechanical arms with multiple degrees of freedom and large motion range to work cooperatively, so that the ground simulation verification is more difficult, and a more complex and accurate microgravity simulation device and method need to be designed.

In the prior art, the mechanical arm ground microgravity simulation environment development test is mostly carried out by adopting an air floatation method or a suspension method, and the mechanical arm is arranged on a fixed simulation wall or a support vehicle. During the test, the degree of freedom and the range of the unfolding motion of the mechanical arm are greatly limited. And because the influence of the acting force and the moment of the mechanical arm on the fixed mounting position is not considered, the gravity unloading is carried out on the main arm rod of the mechanical arm by a plurality of needles, the whole mechanical arm adopts double lifting points or single lifting point, and although the gravity of the whole mechanical arm is unloaded, the moment of the joint has larger deviation.

When the mechanical arm for the spacecraft is used for carrying out tests such as target capture, the mechanical arm is arranged on an air bearing table or a parallel mechanism with six-degree-of-freedom activity capability, moment deviation at the root part of the mechanical arm can greatly influence the posture of the spacecraft, and a capture simulation test fails. Sometimes, the state of the spacecraft in a capturing test and other tests is verified for more real simulation, so that the motion of the mechanical arm is limited.

Disclosure of Invention

The invention aims to solve the problem of providing a space manipulator suspension microgravity simulation method, by adopting the method, the simulation state is closer to the actual application state and is more accurate and reliable, the positions of each lifting point of the space manipulator are controlled to move along with a target by constructing a set of mechanical swing arm system capable of actively controlling and rapidly responding, the gravity of the space manipulator and the gravity of a plurality of manipulator joints are fully unloaded by a specially designed multipoint suspension structure, the action of the gravity of the space manipulator on the posture of a spacecraft when the manipulator is unfolded is eliminated, more motion freedom degrees and motion ranges of the manipulator are reserved, and the expansion range of the space manipulator is adapted in a larger range.

In order to solve the technical problems, the invention adopts the technical scheme that: the space manipulator suspension microgravity simulation method comprises the following steps,

s1, mounting the space manipulator on the six-degree-of-freedom platform in a folded state, and controlling the six-degree-of-freedom platform to move to a test starting position on the air floatation platform;

s2, controlling the omnidirectional moving platform to move to enable the microgravity simulation device to move to a position near the six-degree-of-freedom platform, and adjusting the alignment position according to the six-degree-of-freedom platform target point;

s3, controlling the mechanical swing arm to move, enabling the suspension component of the mechanical swing arm to move to the corresponding lifting point position of the space manipulator, and connecting the suspension component with the lifting point;

s4, controlling the six-degree-of-freedom platform to move to a corresponding position close to a capture target on the air floatation platform, and controlling the omnidirectional moving platform to move along with the six-degree-of-freedom platform;

s5, controlling the space manipulator to unfold, namely unfolding the small arm rod outwards, controlling the large arm rod and the small arm rod to be linked to enable the tail end execution joint to be close to a capture target, and controlling the mechanical swing arm to move along with the space manipulator to enable the suspension assembly to be kept above the suspension point at any time;

s6, after the space manipulator completes the test, controlling the space manipulator to move to the original furled state, and controlling the mechanical swing arm to move along with the space manipulator so that the suspension assembly is kept above the suspension point all the time;

s7, after the six-degree-of-freedom platform moves to the parking position, closing the air source, and supporting and fixing the six-degree-of-freedom platform;

and S8, disassembling the suspension assembly, moving the omnidirectional moving platform to a parking position away from the position of the six-degree-of-freedom platform, turning off an air source power supply, and ending the test.

Further, in step S1, simplifying the space manipulator that needs to unload gravity into a joint and arm rod structure with uniform mass, where the space manipulator includes a shoulder deflection joint, a large arm rod, an elbow joint, a small arm rod, a wrist deflection joint, a wrist rolling joint and a tail end execution joint that are sequentially arranged and move;

the shoulder rolling joint, the shoulder pitching joint and the shoulder deflecting joint of the space manipulator form a root joint;

setting the following parameter definitions, wherein the mass of a root joint, an elbow joint and a wrist deflection joint is m1kg, the weight of a small arm tail end deflection joint and a tail end execution joint is m2kg, the weight of a large arm and a small arm are m3kg, the distance between the root joint and the elbow joint is D1mm, the distance between the elbow joint and the wrist deflection joint is D2mm, the distance between the wrist execution joint and the tail end execution joint is D3mm, the root lifting point force of a large arm rod is F1, and the root deflection joint is positioned at the position D6mm away from the root joint; elbow suspension point force F2; the lifting point force at the tail end of the forearm is F3 and is positioned at a position D4mm away from the elbow joint; the wrist suspension point force is F4; the tail end execution joint lifting point force is F5, the balance weight is far away from the wrist lifting point D5mm, the gravity is G1, and the wrist lifting point and tail end lifting point converging lifting point force Fa is F4+ F5+ G1 and is positioned above the center of the wrist deflection joint; the hoisting points F3 at the tail ends of the small arms and Fa are converged into a hoisting point Fb through a special-shaped transverse link mechanism, the Fb hoisting point is correspondingly connected with the hoisting point of the small swing arm B of the mechanical swing arm, and the torque output by each hoisting point is balanced; f3 is a distance Fb of x, Fa is a distance Fb of y, and the sum of the values of x and y is a fixed number.

Furthermore, a shoulder rolling joint and a shoulder pitching joint of the space manipulator are fixed on the six-degree-of-freedom platform, the position and the posture of the space manipulator do not change relative to the six-degree-of-freedom platform in the test process, the gravity of the space manipulator is adjusted and balanced by a balance weight on the six-degree-of-freedom platform, and the suspension gravity unloading is not carried out.

Further, F5 ═ m2kgf, F4 ═ m1 kgf;

the moment at Fa is balanced and,

Fa＝F4+F5+G1＝13.78kgf；

f3: the small arm and the small arm tail end joint unload the gravity, the moment balance of the elbow is considered,

calculating and determining the value of F3, wherein Fb is F3+ Fa;

moment balance at Fb, if F3 is x away from Fb and Fa is y away from Fb, then:

calculating the values of x and y to determine the position of Fb;

f1+ F2+ F3, which is the sum of the weights of the root joint, the big arm, the elbow joint, the small arm and the small arm tail end deflection joint, and the root moment is 0, then:

calculating to obtain values of F1 and F2;

substituting the calculated F1, F2 and F3 values into the calculation of the moment at the elbow joint, wherein the moment at the elbow joint comprises the following steps:

the numerical values on the two sides meet, and the gravity at all positions of the space manipulator is unloaded.

Further, when the small arm rod of the mechanical arm rotates to form a certain angle with the large arm rod, the root joint is set as an original point, the direction of the large arm is an x axis, the vertical direction is a z axis, and the angle between the small arm and the large arm is alpha;

the x-axis moment is:

the y-axis moment is:

the moment of the space mechanical arm on the root in the y-axis direction is irrelevant to the rotation angle of the small arm lever, and the value of My is calculated after the moment is substituted into F1, F2 and F3, so that the moment on the y-axis is determined.

Further, the microgravity simulation device comprises 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 the air bearing platform;

the camera measures a target point on the six-degree-of-freedom platform in real time to obtain the position and posture change of the six-degree-of-freedom platform, and then controls the mechanical swing arm mounting platform to move along with the six-degree-of-freedom platform through the control system;

the mechanical swing arm mounting platform comprises an omnidirectional moving platform, a balance weight and a mechanical swing arm support, and the omnidirectional moving platform moves omnidirectionally in a plane; the counterweight; the mass center of the whole body of the omnidirectional moving platform and the mechanical swing arm is balanced; the mechanical swing arm support moves to compensate the motion precision of the full-moving platform;

the camera is installed on the mechanical swing arm support, and the mechanical swing arm support guarantees that the space manipulator at the lower end moves accurately relative to the six-freedom-table through gravity unloading and the follow-up assembly.

Furthermore, the gravity unloading and follow-up assembly comprises 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 arranged on a mechanical swing arm support, is positioned between the two mechanical swing arms B and is used for controlling the follow-up movement of the root lifting point of the large arm of the space manipulator;

the mechanical swing arms B are symmetrically arranged on the mechanical swing arm support in the left-right direction and respectively correspond to one space mechanical arm. The device is used for controlling the following movement of elbow joint hanging points and small arm tail end hanging points of the space manipulator;

the constant tension assembly actively controls winding and unwinding of the winding wire and controls the suspension force to be relatively constant by adopting a motor, so that the suspension point can adapt to position change in the vertical direction in the unfolding process of the space manipulator, and the suspension assembly is connected below the suspension point;

and the suspension assembly is used for unloading gravity of all parts of the space mechanical arm in the motion process and eliminating additional disturbance moment generated by suspension force.

Furthermore, the following motion control of the mechanical swing arm A is divided into three stages, and the overall position of the first stage is controlled by the omnidirectional moving platform to follow the motion of the six-degree-of-freedom platform; the second stage is that the rotary arm, the linear module A and the beam form two-dimensional motion consisting of rotary motion and linear motion, and a lifting point two-dimensional control mechanism at the tail end of the swing arm A is controlled to more quickly and accurately follow the six-degree-of-freedom platform to move, so that the following motion error of the omnidirectional mobile platform is eliminated; in the third stage, the linear driving module B and the linear driving module C form a left two-dimensional motion mechanism and a right two-dimensional motion mechanism, and the two lifting points of the mechanical swing arm A are respectively controlled to move along with the lifting points of the large arm roots of the two space mechanical arms on the six-degree-of-freedom platform;

mechanical swing arm A includes fixed cantilever, the rotary joint, the gyration is directly driven the motor, the revolving arm, linear drive module A, the crossbeam, the side direction gyro wheel, linear drive module B, linear drive module C and the adaptor A that suspends in midair, mechanical swing arm A wholly removes with omnidirectional movement platform is together, fixed cantilever passes through the rotary joint with the revolving arm and is connected, the revolving axle is through directly driving motor drive, linear drive module A is installed to the revolving arm below, linear motion pair is constituteed by ball linear guide and lead screw to linear drive module A, linear module A slip table connects the crossbeam, the crossbeam is symmetrical structure, two sets of gyro wheels are installed to the crossbeam in the centre, the gyro wheel contacts and has certain pretightning force with the revolving arm both sides face, two sets of linear drive module B are installed to crossbeam lower extreme bilateral symmetry, linear drive module C is installed to every. The linear die set B, C is mounted in a normal orientation.

Furthermore, the suspension assemblies are three groups, are suspension members at the root part of the large arm rod respectively and correspond to the suspension points a of the space manipulator; the elbow suspension piece corresponds to a space manipulator suspension point b; the suspension parts at the tail ends of the small arms correspond to suspension points c, d and e of the space manipulator, three groups of suspension components jointly form a multi-point suspension system, the gravity of each part of the space manipulator from the root joint of the large arm rod to the execution joint part at the tail end of the manipulator is fully unloaded in the motion process, and the additional interference moment generated by the suspension force is eliminated; the large arm rod root suspension piece comprises a rolling connecting ring A; a pitching connecting shaft; an L-shaped long boom; a pin shaft A; a deflection connecting shaft A; the pin B and the lifting rope form a A, wherein the rolling connecting ring A is connected with the space manipulator and rolls and rotates around the space manipulator,

the rolling connecting ring, the pitching connecting shaft and the deflection connecting shaft form three orthogonal rotating shafts, and the suspension piece at the root part of the large arm rod and the space manipulator form a universal connecting mechanism;

the L-shaped long suspender enables the suspension part at the root part of the large arm rod to avoid other mechanisms when the space manipulator is in a furled state, and enables a suspension point to be always positioned at the middle shaft position of the arm rod; the rolling connecting ring A comprises a roller, an outer rolling ring and an inner fixing ring, the inner side ring surface of the inner fixing ring is tightly held by the space mechanical arm to be connected and fixed, the outer side ring surface is provided with a rolling groove of the roller, the outer rolling ring is assembled into a whole ring by two semi-rings and is uniformly provided with a plurality of rollers, and the assembled roller can roll and rotate in the annular groove of the inner fixing ring;

the elbow suspension piece comprises a rolling connecting ring B, a pitching connecting shaft B, U type lifting claw, a short rod, a pin shaft C, a transverse connecting rod, a pin shaft D, a deflection connecting shaft B and a lifting rope assembly B; the elbow suspension piece enables the suspension point to be located at the position of the rotation axis of the elbow joint, two symmetrically arranged rolling connecting rings are fixed on two sides of the elbow joint, a parallel four-bar mechanism is formed by the U-shaped suspension claws, the transverse connecting bar, the pin shaft D and the like, and the suspension point located in the middle of the transverse connecting bar is always located at the center of the rotation axis of the elbow joint.

Furthermore, the small arm tail end suspension piece comprises three suspension points, a rolling connecting ring C, a pitching connecting shaft C, U type long suspension claw, a deflection pin shaft and a short rod form a small arm suspension mechanism, namely the suspension mechanism of the suspension point C, and the suspension mechanism has 3 degrees of freedom of rolling, pitching and deflection, so that the small arm suspension mechanism is subjected to constant vertical suspension force equal to the required unloading gravity;

the wrist joint suspension mechanism is composed of a deflection connecting shaft D, a pin shaft H, a long transverse connecting rod 4, a pin shaft I, a short rod, a U-shaped suspension claw, a pitching connecting pin shaft and a rolling connecting ring D, namely a suspension mechanism at a suspension point D, the suspension force is the gravity of a wrist joint, and the parallel four-connecting-rod mechanism is composed of two groups of rolling connecting rings, U-shaped suspension claws and the like and the transverse connecting rod, so that the suspension point is ensured to be always positioned in the center of a rotating shaft of the wrist joint and is connected with a special-shaped transverse connecting rod through a pin shaft G;

the L-shaped short suspender, a pin shaft K, a connecting plate, a rolling connecting ring E, a long transverse connecting rod and a balancing block form a tail end execution joint suspension mechanism, namely a suspension mechanism with a suspension point E, the suspension force is the gravity of the tail end execution joint, two groups of rolling connecting rings are symmetrically connected and fixed on two sides of a tail end execution joint rotating shaft and are connected into a whole by the connecting plate, the center of the connecting plate is connected with the L-shaped short suspender through the pin shaft, the upper end of the L-shaped short suspender is connected with the long transverse connecting rod through the pin shaft J, the suspension force is located at one end of the pin shaft J of the long transverse connecting rod and is located above the center of the tail end execution joint, and the suspension force is balanced through the.

Compared with the prior art, the invention has the following advantages and positive effects.

1. The invention designs an active following type mechanical swing arm and multipoint suspension assembly, which is characterized in that a mechanical swing arm system capable of actively controlling and rapidly responding is constructed to control the positions of each lifting point of a space mechanical arm to move along with a target, the gravity of the space mechanical arm and the gravity of a plurality of mechanical arm joints are fully unloaded through a specially designed multipoint suspension structure, the effect of the gravity of the space mechanical arm on the attitude of a spacecraft when the mechanical arm is unfolded is eliminated, and meanwhile, more motion freedom degrees and motion ranges of the mechanical arm are reserved, and the expansion range of the space mechanical arm is adapted in a larger range;

2. the space manipulator is arranged on the six-degree-of-freedom simulation platform, the space manipulator is unfolded to perform actions such as target capture and the like, and the six-degree-of-freedom platform simulates the motion attitude of the spacecraft in real time in the capture experiment process of the space manipulator; the omnidirectional moving platform, the balance weight and the mechanical swing arm support in the device form a mechanical swing arm mounting platform which actively follows the six-freedom-degree platform to move, a camera on the mechanical swing arm support is used for measuring a target point on the six-freedom-degree platform in real time, the position and the posture of the six-freedom-degree platform are obtained, the omnidirectional moving platform is further controlled to follow the six-freedom-degree platform to move, the fixed relative position of the omnidirectional moving platform which always follows the rear part of the six-freedom-degree platform is kept, and the mechanical swing arm and the space manipulator can keep a constant relative position. In consideration of the reasons of large load, large control difficulty and the like of the omnidirectional mobile platform, in order to improve the real-time following dynamic characteristic of the omnidirectional mobile platform and allow the following motion of the omnidirectional mobile platform to have a certain error range, the error is corrected and compensated through the motion of a mechanical swing arm with higher motion precision and dynamic motion performance, and the motion precision is ensured;

3. compared with the previous experiments, the microgravity simulation device for the space target capture, despin and other experiments on the ground is used for unloading the gravity of a plurality of lifting points on the space manipulator, so that the space manipulator can be allowed to move in a larger range in the test process, the influence of the gravity on the spacecraft attitude simulation is eliminated, and the test process is more real and accurate;

4. the mechanical swing arm has high dynamic response capability and motion position precision by selecting a high-performance direct drive motor, a high-precision transmission system, and accurate position feedback and lightweight structural design, so that the precise dynamic control of the position of a lifting point is realized.

5. The suspension assembly realizes gravity unloading and large-range space motion of the space manipulator, the constant force device is adopted to control suspension force of each suspension point to be constant, and in the motion process of the space manipulator, the motor in the constant force device controls the retraction of the suspension rope and keeps the stability of the required suspension force.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1-A is a side view of a space manipulator suspension microgravity simulation method of the present invention;

FIG. 1-B is a top view of a space manipulator suspension microgravity simulation method of the present invention;

FIG. 2 is a schematic structural diagram of a swing arm A of the present invention;

FIG. 3-A is a side view of the swing arm B of the present invention;

FIG. 3-B is a schematic structural diagram of the mechanical swing arm B of the present invention viewed from above;

FIG. 3-C is a cross-sectional view of a mechanical swing arm B of the present invention;

FIG. 4-A is a side view of the suspension assembly of the present invention and the corresponding spatial robotic arm suspension location;

FIG. 4-B is a schematic diagram of the suspension assembly of the present invention and the corresponding spatial robotic arm suspension position;

FIG. 5-A is a view of the boom root suspension of the present invention;

FIG. 5-B is an enlarged view of a portion of the lower end of the boom root suspension of the present invention;

FIG. 6 is a view of an elbow suspension of the present invention;

FIG. 7 is a view of a lower arm end suspension of the present invention;

FIG. 8 is a force analysis diagram of the space manipulator of the present invention;

FIG. 9 is a schematic view of the space manipulator arm rotated at an angle to the boom arm of the present invention;

FIG. 10 is a schematic view of the construction of the space robot of the present invention;

fig. 11 is a schematic structural diagram of a space manipulator suspension microgravity simulation method according to the invention.

Description of the drawings:

1. an omnidirectional mobile platform; 2. balancing weight; 3. a mechanical swing arm support; 4. a camera; 5. a mechanical swing arm A; 6. a mechanical swing arm B; 7. a constant tension assembly; 8. a suspension assembly; 9. a space manipulator; 10. a six degree of freedom platform; 5-1, fixing the cantilever; 5-2, a revolute joint; 5-3, rotating a direct drive motor; 5-4, a revolving arm; 5-5, a linear driving module A; 5-6, a cross beam; 5-7, lateral rollers; 5-8, a linear driving module B; 5-9, a linear driving module C; 5-10, a suspension adapter A; 6-1, fixing seats; 6-2, a large swing arm rotary direct drive motor; 6-3, a large swing arm rotary joint; 6-4, a large swing arm; 6-5, a large-pendulum linear motor; 6-6, a large pendulum straight line module; 6-7, a small pendulum rotary direct drive motor; 6-8, a small pendulum rotary joint; 6-9 parts of a small swing arm; 6-10, a small pendulum straight line module; 6-11, a small pendulum linear motor; 6-12, a suspension adapter B; 8-1, hanging parts at the root parts of the large arm levers; 8-2, an elbow suspension; 8-3, a small arm end suspension piece; 8-1-1, rolling the connecting ring A; 8-1-2, a pitching connecting shaft A; 8-1-3, L-shaped long hanger rod; 8-1-4, pin shaft A; 8-1-5, a deflection connecting shaft A; 8-1-6 and a pin B; 8-1-7, and a lifting rope to form A; 8-1-1a, a roller; 8-1-1b, an outer rolling ring; 8-1-1c, an inner fixing ring; 8-2-1, rolling the connecting ring B; 8-2-2 and a pitching connecting shaft B; 8-2-3, U-shaped lifting claws; 8-2-4, short rod; 8-2-5, and a pin shaft C; 8-2-6, a transverse connecting rod; 8-2-7 and a pin shaft D; 8-2-8, a deflection connecting shaft B; 8-2-9 and a lifting rope form B; 8-3-1, rolling the connecting ring C; 8-3-2, a pitching connecting shaft C; 8-3-3, U-shaped long hanging claws; 8-3-4, deflecting pin shafts; 8-3-5, short rod; 8-3-6, pin E; 8-3-7 of a special-shaped transverse connecting rod; 8-3-8, and a pin shaft F; 8-3-9, a deflection connecting shaft C; 8-3-10, pin shaft G; 8-3-11, a deflection connecting shaft D; 8-3-12, pin shaft H; 8-3-13 parts of long transverse connecting rod; 8-3-14, pin I; 8-3-15, short rod; 8-3-16, U-shaped lifting claws; 8-3-17, a pitching connecting pin shaft; 8-3-18, rolling the connecting ring D; 8-3-19 and a pin shaft J; 8-3-20 of L-shaped short hanger rods; 8-3-21, pin roll K; 8-3-22, connecting plates; 8-3-23, rolling the connecting ring E; 8-3-24, balance weight; 8-3-25 and a lifting rope form C; 9-1, shoulder rolling joints; 9-2, shoulder pitch joint; 9-3 shoulder yaw joints; 9-4, a large arm rod; 9-5, elbow joint; 9-6, a small arm rod; 9-7, wrist deflection joint; 9-8, wrist rolling joint; 9-9, the end effector joint.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in relative terms of orientation or position to facilitate describing the invention and to simplify the description, but do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be considered limiting of the invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The following is a detailed description of specific embodiments of the invention.

The principle of the invention for solving the technical problem is as follows:

aiming at the mechanical arm microgravity simulation of a space target capture test, the space mechanical arm has the following technical problems: (1) the space manipulator generates position and attitude changes along with the motion and attitude changes of the six-degree-of-freedom simulation platform; (2) the space manipulator has more moving joints and a large expansion range; (3) in a space manipulator capture test, the influence of the moment generated by the motion of the manipulator in the mechanical arm unfolding process on the six-degree-of-freedom platform is simulated as truly as possible, and the influence of the self gravity of the space manipulator on the six-degree-of-freedom platform is fully unloaded.

As shown in fig. 1-a and fig. 1-B, the space manipulator suspension microgravity simulation method includes an omnidirectional mobile platform 1, a counterweight 2, a mechanical swing arm support 3, a camera 4, a mechanical swing arm a5, a mechanical swing arm B6, a constant tension assembly 7, a suspension assembly 8 and a six-degree-of-freedom platform 10, and is used for microgravity simulation test of a space manipulator 9, and the six-degree-of-freedom platform is arranged on an air bearing platform; the camera 4 measures a target point on the six-degree-of-freedom platform in real time to obtain the position and posture change of the six-degree-of-freedom platform, and then controls the mechanical swing arm mounting platform to move along with the six-degree-of-freedom platform through the control system; the mechanical swing arm mounting platform comprises an omnidirectional moving platform 1, a balance weight 2 and a mechanical swing arm support 3, and the omnidirectional moving platform 1 moves omnidirectionally in a plane; a counterweight 2; the device is used for balancing the integral mass center of the omnidirectional moving platform 1 and the mechanical swing arm; the mechanical swing arm support 3 is used for compensating the motion precision of the full-moving platform through the motion of the mechanical swing arm support; the camera 4 is installed on the mechanical swing arm support 3, and the lower end of the mechanical swing arm support 3 is provided with a space mechanical arm 9.

Preferably, the omni-directional mobile platform 1: the main part is the AGV car, realizes through 4 mecanum wheels that the AGV car is at plane omnidirectional movement. In order to realize large load and faster response capability, an air cushion is adopted to support the AGV, and 4 Mecanum wheels keep a certain supporting force with an air floating platform through suspension. In the experimental process, because most weight is supported by the air cushion, the AGV car can more steady motion. The top end of the AGV car is a load table board, and an interface is processed on the load table board and connected with a mechanical swing arm support 3.

Preferably, the weight 2: the counter weight 2 is stacked on the bottom frame of the mechanical swing arm support 3 in a multi-layer mode through steel plates and is used for balancing the whole mass center of the omnidirectional moving platform 1 and the whole mass center of the mechanical swing arm, so that the whole motion is stable, and overturning is prevented.

Preferably, the mechanical swing arm support 3: mechanical swing arm support 3 is three-layer frame spiro union and constitutes, from upwards being the bottom frame down, highly adapted frame and swing arm linking bridge, the bottom frame bottom is through the bolt, the adjustment parallels is connected with 1 mesa of omnidirectional movement platform, the adjustment parallels is used for the leveling of mechanical swing arm support 3, highly adapted frame is connected to bottom frame top surface anterior segment, rear end installation counter weight 2 board, swing arm linking bridge installs at highly adapted frame top surface, it is connected with mechanical swing arm and gets the installation and hang out the certain distance forward to the face, make mechanical swing arm mounted position as far as possible be close to space arm 9, connect the face lower extreme installation two cameras 4 in the swing arm and be used for measuring the position and the gesture of six degree of freedom platforms.

Preferably, the camera 4: the cameras 4 are used for measuring the pose of a target point, two cameras 4 are mounted at the lower end of the connecting surface of the swing arm in the mechanical swing arm support 3 and used for measuring the position and the pose of the omnidirectional moving platform 1 relative to the six-degree-of-freedom platform, and the cameras 4 are mounted on the mechanical swing arm and used for measuring the position and the pose of the space manipulator 9 relative to the mechanical swing arm.

Preferably, the mechanical swing arm a 5: the mechanical swing arm A5 is installed on the mechanical swing arm support 3, is located between the two mechanical swing arms B6, and is used for controlling the following movement of the root hoisting point of the large arm lever of the space manipulator 9. As shown in fig. 2, the mechanical swing arm a5 basically comprises: the device comprises a fixed cantilever 5-1, a rotary joint 5-2, a rotary direct drive motor 5-3, a rotary arm 5-4, a linear driving module A5-5, a cross beam 5-6, a lateral roller 5-7, a linear driving module B5-8, a linear driving module C5-9 and a suspension adapter A5-10.

Wherein, the fixed cantilever 5-1 is arranged on the mechanical swing arm bracket 3, and the mechanical swing arm A5 integrally moves together with the omnidirectional moving platform 1. The fixed cantilever 5-1 is connected with the rotary arm 5-4 through a rotary joint 5-2. The rotary joint 5-2 is formed by assembling a precisely machined shaft and a high-precision bearing, the mechanical precision of rotary motion is guaranteed, the rotary shaft is driven by a direct-drive motor, and the direct-drive motor is integrated with a high-precision encoder as feedback, so that the control precision of rotation is guaranteed. A linear driving module A5-5 is arranged below the rotary arm 5-4. The linear module A is a linear motion pair consisting of a ball linear guide rail and a lead screw, the lead screw is driven by a motor integrated with a high-precision absolute value encoder to realize linear motion of the linear module sliding table, and the linear transmission is calibrated and compensated to ensure enough transmission precision. The linear module A sliding table is connected with cross beams 5-6, the cross beams 5-6 are of a symmetrical structure, two groups of rollers are arranged in the middle of the cross beams 5-6, the rollers are in contact with two side faces of the rotary arm 5-4 and have certain pretightening force, and the rollers are used for roll protection when the cross beams 5-6 move linearly. Two groups of linear driving modules B5-8 are symmetrically arranged at the left and right of the lower end of the cross beam 5-6, and a linear driving module C5-9 is arranged on a sliding table of each linear driving module B5-8. The linear module B, C is installed in normal direction, the structure is similar to that of the linear driving module A5-5, a linear motion pair is formed by a ball linear guide rail and a lead screw, the lead screw is driven by a motor integrated with a high-precision absolute value encoder to realize linear motion of a linear module sliding table, and the linear transmission is calibrated and compensated to ensure enough transmission precision. A suspension adapter A5-10 is installed on a sliding table of the linear driving module C5-9, and the suspension adapter A5-10 is used for installing a constant force device and a suspension assembly 8, and the position of the suspension adapter A corresponds to the position of a suspension point at the root of a large arm rod of the space manipulator 9.

The following motion control of the mechanical swing arm A5 is divided into three stages, and the overall position of the first stage is controlled by the omnidirectional moving platform 1 to follow the motion of the six-degree-of-freedom platform; the second stage is that the rotary arm 5-4, the linear module A and the beam 5-6 form two-dimensional motion consisting of rotary motion and linear motion, a lifting point two-dimensional control mechanism at the tail end of the swing arm A is controlled to move along with the six-degree-of-freedom platform more quickly and accurately, and the following motion error of the omnidirectional moving platform 1 is eliminated; and in the third stage, the linear driving module B5-8 and the linear driving module C5-9 form a left two-dimensional motion mechanism and a right two-dimensional motion mechanism, and respectively control two suspension points of the mechanical swing arm A5 to move along with the suspension points at the root parts of the large arm levers of the two space mechanical arms 9 on the six-degree-of-freedom platform.

Preferably, mechanical swing arm B6: two sets of mechanical swing arms B6 are provided, and are symmetrical structures, and are symmetrically arranged on the mechanical swing arm bracket 3 left and right, and respectively correspond to one space manipulator 9. Used for controlling the following movement of the elbow joint hoisting point and the small arm tail end hoisting point of the space manipulator 9. As shown in fig. 3, the mechanical swing arm B6 basically comprises: the device comprises 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 drive motor and a suspension adapter B.

Wherein, the fixing base is installed on mechanical swing arm support 3, and mechanical swing arm B6 is whole to move with omnidirectional movement platform 1 together. The fixed seat is connected with the large swing arm through a rotary joint 5-2. The rotary joint 5-2 is formed by assembling a precisely machined shaft and a high-precision bearing, the mechanical precision of rotary motion is guaranteed, the rotary shaft is driven by a direct-drive motor, the direct-drive motor is integrated with a high-precision encoder as feedback, the control precision of rotary motion is guaranteed, a large-pendulum linear module is installed on the inner side of a large swing arm, a linear motion pair is formed by a ball linear guide rail and a lead screw, the motor integrated with a high-precision absolute value encoder drives the lead screw to achieve linear motion of a linear module sliding table, and the linear motion is calibrated and compensated to guarantee enough transmission precision. The large-pendulum linear module sliding table is connected with a small-pendulum rotary joint 5-2, the upper end of the rotary joint 5-2 is connected with a small-pendulum rotary direct-drive motor 5-3 for driving the rotary joint 5-2 to rotate, and an output shaft at the lower end of the rotary joint 5-2 is connected with a small swing arm. Two groups of small pendulum linear modules are mounted on the bottom surface of the lower swing arm and driven by a motor with a precision feedback encoder, a sliding table of each small pendulum linear module is provided with a suspension adapter B for mounting a constant force device and a suspension assembly 8, and the positions of the small pendulum linear modules correspond to the positions of elbow suspension points of the space manipulator 9 and tail suspension points of the small arm respectively.

Preferably, the constant tension assembly 7: the constant tension assembly 7 actively controls winding and unwinding of the coiled wire and controls the suspension force to be relatively constant by adopting a motor, so that the suspension point can adapt to the position change of the space manipulator 9 in the vertical direction in the unfolding process. The constant tension component 7 is arranged on the suspension adapter, and the suspension component 8 is connected below the constant tension component.

Preferably, the multipoint suspension assembly: the suspension components are connected with the space manipulator, three groups of suspension components are designed, as shown in fig. 4, the suspension components are suspension pieces at the root part of a large arm rod and correspond to a suspension point a of the space manipulator; the elbow suspension piece corresponds to a space manipulator suspension point b; the suspension pieces at the tail ends of the small arms correspond to suspension points c, d and e of the space manipulator, three groups of suspension components jointly form a multi-point suspension system, actually 5 suspension points are realized, and suspension force of each suspension point is calculated and distributed, so that gravity of each part of the space manipulator from a root joint of the large arm rod to an execution joint part at the tail end of the manipulator is fully unloaded in the motion process, and additional interference torque generated by the suspension force is eliminated.

The large arm stem root suspension 8-1 is shown in fig. 5, and comprises a rolling connection ring A8-1-1; a pitching connecting shaft A8-1-2; 8-1-3 of an L-shaped long suspender; a pin shaft A8-1-4; the deflection connecting shaft A8-1-5; the pin shaft B8-1-6 and the lifting rope form A8-1-7, wherein the rolling connecting ring is connected with the space manipulator and can roll and rotate around the manipulator arm rod, and the rolling connecting ring comprises a roller 8-1-1a, an outer rolling ring 8-1-1B and an inner fixing ring 8-1-1 c.

The multipoint suspension assembly and the space manipulator are connected by adopting the structure, the inner side ring surface of the inner fixing ring 8-1-1c tightly holds the space manipulator to be connected and fixed, the outer side ring surface is provided with a 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 is uniformly provided with 4 rollers 8-1-1a, and the roller 8-1-1a can roll and rotate in the ring groove of the inner fixing ring 8-1-1c after being assembled. The rolling connecting ring, the pitching connecting shaft and the deflecting connecting shaft form three orthogonal rotating shafts, so that the large arm rod root suspension part and the space mechanical arm form a universal connecting mechanism, the suspension assembly can adapt to various motions of deflection, pitching and rolling of the mechanical arm, the L-shaped long suspension rod 8-1-3 can enable the large arm rod root suspension part to avoid other mechanisms when the space mechanical arm is in a folded state, and a suspension point is always located at the position of a middle shaft of the arm rod.

The elbow suspension piece is shown in figure 6 and comprises a rolling connecting ring B8-2-1, a pitching connecting shaft B8-2-2, a U-shaped lifting claw 8-2-3, a short rod 8-2-4, a pin shaft C8-2-5, a transverse connecting rod 8-2-6, a pin shaft D8-2-7, a deflecting connecting shaft B8-2-8 and a lifting rope B8-2-9; the elbow suspension piece adopts two symmetrically arranged rolling connecting rings to be fixed at two sides of an elbow joint for enabling a suspension point to be positioned at the position of an elbow joint rotating axis, and a parallel four-bar mechanism is formed by the U-shaped suspension claws 8-2-3, the transverse connecting rods 8-2-6, pin shafts and the like, so that when the space manipulator generates deflection, pitching and other motions, the suspension point positioned in the middle of the transverse connecting rods 8-2-6 is always positioned at the elbow joint rotating axis center.

The suspension piece at the tail end of the forearm is complex and integrates three suspension points, as shown in fig. 7, a rolling connecting ring C8-3-1, a pitching connecting shaft C8-3-2, a U-shaped long suspension claw 8-3-3, a deflecting pin 8-3-4, a short rod 8-3-158-5, a pin E8-3-6, a special-shaped transverse connecting rod 8-3-7, a pin F8-3-8, a deflecting connecting shaft C8-3-9, a pin G8-3-10, a deflecting connecting shaft D8-3-11, a pin H8-3-12, a long transverse connecting rod 8-3-134, a pin I8-3-14, a short rod 8-3-158-5, a U-shaped suspension claw 8-3-16, a pin I8-12, a long transverse connecting rod 8-3-134, a pin I, 8-3-17 parts of pitching connecting pin shaft, 8-3-18 parts of rolling connecting ring D8-3-18 parts of pin shaft J8-3-19 parts of L-shaped short suspender 8-3-20 parts of pin shaft K8-3-21 parts of connecting plate 8-3-22 parts of rolling connecting ring E8-3-23 parts of balancing block 8-3-24 parts of lifting rope, and C8-3-25 parts of lifting rope.

Wherein: the roll connecting ring C8-3-1, the pitch connecting shaft C8-3-2, the U-shaped long hanging claw 8-3-3, the deflection pin shaft 8-3-4 and the short rod 8-3-158-3-5 form a small arm hanging mechanism, namely a hanging point C hanging mechanism which has 3 degrees of freedom of roll, pitch and deflection and is connected through a pin shaft E8-3-6 and a special-shaped transverse connecting rod 8-3-7, and the position of the pin shaft F8-3-8 on the special-shaped transverse connecting rod 8-3-7 is calculated and distributed, so that the small arm hanging mechanism is subjected to constant vertical hanging force equal to the required unloading gravity.

Wherein: the wrist joint suspension mechanism is composed of deflection connecting shafts D8-3-11, pin shafts H8-3-12, long transverse connecting rods 8-3-134, pin shafts I8-3-14, short rods 8-3-158-5, U-shaped suspension claws 8-3-16, pitching connecting pin shafts 8-3-17 and rolling connecting rings D8-3-18, namely a suspension mechanism at a suspension point D, the suspension force of the suspension mechanism is the weight of a wrist joint, the structure of the suspension mechanism is similar to that of an elbow suspension part, two groups of rolling connecting rings, U-shaped suspension claws 8-3-16 and the like are used for forming a parallel four-bar linkage mechanism with the transverse connecting rods, the suspension point is ensured to be always positioned at the center of a rotating shaft of the wrist joint, and the suspension mechanism is connected with special-shaped transverse connecting rods 8-3-7 through pin shafts G8-3-10.

Wherein: the L-shaped short suspender 8-3-20, the pin shaft K8-3-21, the connecting plate 8-3-22, the rolling connecting ring E8-3-23, the long transverse connecting rod 8-3-13 and the balancing block 8-3-24 form a tail end execution joint suspension mechanism, namely a suspension mechanism at a suspension point E, the suspension force is the tail end execution joint gravity, structurally, two groups of rolling connecting rings are symmetrically connected and fixed on two sides of a tail end execution joint rotating shaft and connected into a whole by the connecting plate 8-3-22, the center of the connecting plate 8-3-22 is connected with the L-shaped short suspender 8-3-20 through the pin shaft, and the upper end of the L-shaped short suspender 8-3-20 is connected with the long transverse connecting rod 8-3-13 through the pin shaft J8-3-19. The suspension force is positioned at one end of a pin shaft J8-3-19 of the long transverse connecting rod 8-3-13 and is always positioned above the center of the tail end execution joint, and the suspension force is balanced through a balance block 8-3-24, so that the moment at the pin shaft H8-3-12 of the long transverse connecting rod 8-3-13 is balanced.

Further, F5 ═ m2kgf, F4 ═ m1 kgf;

the moment at Fa is balanced and,

Fa＝F4+F5+G1＝13.78kgf；

calculating and determining the value of F3, wherein Fb is F3+ Fa;

moment balance at Fb, if F3 is x away from Fb and Fa is y away from Fb, then:

calculating the values of x and y to determine the position of Fb;

calculating to obtain values of F1 and F2;

the x-axis moment is:

the y-axis moment is:

the moment of the space mechanical arm on the root in the y-axis direction is irrelevant to the rotation angle of the small arm lever, the My value is calculated after the moment is substituted into F1, F2 and F3, and the moment of the space mechanical arm on the y-axis is determined to be 0, namely, the sufficient unloading is proved.

The specific embodiment is as follows: the space manipulator needing gravity unloading is simplified into a joint and arm rod structure with uniform mass as shown in fig. 8, wherein the mass of a root joint, an elbow joint and a wrist deflection joint is 6kg, the weight of a small arm tail end deflection joint and a small arm tail end execution joint is 3kg, and the weight of a large arm and a small arm is 10 kg. The root is 1060mm from the elbow, the elbow is 1060mm from the wrist-offset joint, and the wrist is 180mm from the end effector joint. The lifting point force of the root part of the large arm lever is F1 and is positioned at the position 100mm away from the root joint; elbow suspension point force F2; the lifting point force of the tail end of the forearm is F3 and is positioned 725mm away from the elbow joint; the wrist suspension point force is F4; the end effector joint suspension force is F5. The balance block is 113mm away from the wrist lifting point, the gravity is G1, and the joint lifting point force Fa of the wrist lifting point and the tail end lifting point is F4+ F5+ G1 and is positioned above the center of the wrist deflection joint; the lifting points F3 at the tail ends of the small arms and Fa are converged into a lifting point Fb through a special-shaped transverse link mechanism, and the Fb lifting point is correspondingly connected with the lifting point of the small swing arm B of the mechanical swing arm.

From the gravity unloading requirement, F5 ═ 3kgf, F4 ═ 6 kgf;

moment balance at Fa, including:

then there are: fa ═ F4+ F5+ G1 ═ 13.78 kgf;

f3 unload forearm and forearm end execution joint gravity, consider elbow moment balance, have:

calculating to obtain F3-11.697 kgf, and Fb-F3 + Fa-25.46 kgf;

to balance the moment at Fb, assuming that F3 is x away from Fb and y away from Fb, then:

the Fb position is determined by calculating x 181.2mm and y 153.8 mm.

F1+ F2+ F3 is 6+10+6+10+3(kgf), which is the sum of the weights of the root joint, the upper arm, the elbow joint, the lower arm and the tip deflection joint of the lower arm.

And the root moment is 0, then:

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

f1-12.146 kgf and F2-11.158 kgf were calculated.

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

therefore, at the moment, no additional moment generated by gravity and suspension force exists at the elbow joint of the space manipulator, and the gravity at each position of the space manipulator is unloaded sufficiently.

When the small arm of the mechanical arm rotates to form a certain angle with the large arm rod, as shown in fig. 9, the root joint is set as the origin, the direction of the large arm is the x axis, the vertical direction is the z axis, and the angle between the small arm and the large arm is alpha.

The easy-to-obtain moment to the x-axis is:

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

the moment to the y-axis is:

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

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

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

at this time, the moment of the space arm in the y-axis direction of the base is calculated to be 0 by substituting F1, F2, and F3, regardless of the rotation angle of the forearm.

In the motion process of the space mechanical arm, the suspension force and the gravity are always in a moment balance state on all parts of the mechanical arm, and no additional interference moment is generated.

More preferably, the space manipulator is a main execution device for performing experiments such as target capture, and two mechanical arms are symmetrically arranged on a simulation wall on a six-degree-of-freedom platform, and each mechanical arm comprises a shoulder rolling joint 9-1, a shoulder pitching joint 9-2, a shoulder deflecting joint 9-3, a big arm rod 9-4, an elbow joint 9-5, a small arm rod 9-6, a wrist deflecting joint 9-7, a wrist rolling joint 9-8 and an end execution joint 9-9 as shown in FIG. 10.

Gravity unloading performs joints 9-9 for the shoulder yaw joint 9-3, the big arm bar 9-4, the elbow joint 9-5, the small arm bar 9-6, the wrist yaw joint 9-7, the wrist roll joint 9-8, and the tip for the components in which motion occurs. In the microgravity system, the shoulder joint of the space manipulator can realize deflection and pitching actions during testing, the space manipulator can cover a required three-dimensional space for testing under the condition that no obstacle avoidance requirement exists in a test environment, the space manipulator is generally designed with redundant freedom degrees for obstacle avoidance and the like, the shoulder rolling joint 9-1 is limited during testing, the structural complexity of the microgravity suspension simulation device can be greatly reduced, and the test can be realized on engineering.

Under the state that the mechanical arm is unfolded forwards and straightened, the shoulder rolling joint 9-1 can be rolled for 90 degrees under the suspension state of the device, then the shoulder rolling joint 9-1 is fixed, the original yaw joint of the space mechanical arm is changed into a pitching joint, the original pitching joint is changed into a yaw joint, and at the moment, the space mechanical arm can perform pitching and yawing motion within a certain range under the posture. In this state, the space mechanical arm generates a certain deflection moment of the large arm rod 9-4 in the axial direction to the installation position on the six-degree-of-freedom platform, and the elbow hanging point needs to be adjusted or an air floatation follow-up supporting device of the elbow joint 9-5 needs to be added to balance the influence of the moment.

The shoulder rolling joint 9-1 and the shoulder pitching joint 9-2 of the space manipulator are fixed on the six-degree-of-freedom platform, the position and the posture of the space manipulator do not change relative to the six-degree-of-freedom platform in the test process, the gravity of the space manipulator is adjusted and balanced by a balance weight on the six-degree-of-freedom platform, and the suspension gravity unloading is not required.

More preferably, the six-degree-of-freedom stage 10 is a simulation platform for performing physical simulation on a service spacecraft, and simulates linear motion of 3 degrees of freedom through a lower planar air bearing and a vertical constant force cylinder, and simulates rotation of 3 degrees of freedom through an upper air-floating ball bearing, and simulates the mass characteristics of the spacecraft through structural design. And a power and control device for simulating spacecrafts such as a thruster and a gyroscope is arranged on the six-degree-of-freedom platform, so that the movement and attitude adjustment control of the six-degree-of-freedom platform in the test process is realized.

In the actual working process, the method comprises the following steps of S1, installing the space manipulator on the six-degree-of-freedom platform in a folded state, and controlling the six-degree-of-freedom platform to move to a test starting position on the air floatation platform; s2, controlling the omnidirectional moving platform to move to enable the microgravity simulation device to move to a position near the six-degree-of-freedom platform, and adjusting the alignment position according to the six-degree-of-freedom platform target point; s3, controlling the mechanical swing arm to move, enabling the suspension component of the mechanical swing arm to move to the corresponding lifting point position of the space manipulator, and connecting the suspension component with the lifting point; s4, controlling the six-degree-of-freedom platform to move to a corresponding position close to a capture target on the air floatation platform, and controlling the omnidirectional moving platform to move along with the six-degree-of-freedom platform; s5, controlling the space manipulator to unfold, namely unfolding the small arm outwards, controlling the large arm and the small arm to be linked to enable the tail end execution joint to be close to a capture target, and controlling the mechanical swing arm to move along with the space manipulator to enable the suspension assembly to be kept above the suspension point all the time; s6, after the space manipulator completes the test, controlling the space manipulator to move to the original furled state, and controlling the mechanical swing arm to move along with the space manipulator so that the suspension assembly is kept above the suspension point all the time; s7, after the six-degree-of-freedom platform moves to the parking position, closing the air source, and supporting and fixing the six-degree-of-freedom platform; and S8, disassembling the suspension assembly, moving the omnidirectional moving platform to a parking position away from the position of the six-degree-of-freedom platform, turning off an air source power supply, and ending the test.

The omnidirectional moving platform supported by the air cushion can stably and actively follow the six-degree-of-freedom platform to move, so that the microgravity simulation device can always integrally follow the relatively constant position of the space manipulator; the mechanical swing arm system capable of quickly responding to control through the sleeve actively follows the lifting point on the space manipulator to move, and the suspension assembly is controlled to accurately follow the lifting point all the time. The mechanical swing arm is divided into a front part and a rear part to be controlled in two stages, wherein the first part forms a polar coordinate system by the rotary motion of the large swing arm and the linear motion of the swing arm in the length direction, and the polar coordinate system can accurately and quickly follow the position change of the space mechanical arm on the six-degree-of-freedom platform to carry out small-range adjustment and eliminate the error followed by the omnidirectional mobile platform; the second stage is position following control of the suspension assembly, and the mechanical swing arm A adopts two-stage linear motion to form two-dimensional movement control space mechanical arm large arm rod root suspension assembly to move along with the suspension point; the mechanical swing arm B forms a polar coordinate motion control space manipulator elbow suspension assembly and a small arm tail end suspension assembly to move along with the suspension point through the rotary motion of the small swing arm and the linear motion of the small swing arm, each suspension assembly controls the vertical direction to move along with the suspension point through a constant force device for actively winding and unwinding the suspension rope, and therefore the multiple suspension points can follow the space manipulator to perform unfolding motion.

By the suspension assembly which can adapt to multi-joint motion of the mechanical arm and the calculation and distribution of the suspension force of each suspension point, the gravity of the motion part of the space mechanical arm is fully unloaded, and the influence of the gravity on the six-degree-of-freedom platform is eliminated. The invention discloses a suspension assembly for executing joint motion aiming at the tail end of a space manipulator, wherein 3 suspension points are integrated into one position, and the mechanical swing arm is used for controlling 3 groups of suspension assemblies to move along to realize gravity unloading of 5 suspension points.

In the test process, the space manipulator starts to control to be unfolded according to a motion instruction, the upper mechanical swing arm controls to swing along with the motion, so that the lifting point on the mechanical swing arm moves along with the motion track of the corresponding suspension point on the space manipulator, meanwhile, each joint encoder of the space manipulator feeds back the position and the moment change of the space manipulator in real time, and the positions of the lifting point of the mechanical swing arm and the lifting point on the space manipulator are kept consistent in control; in addition, the camera on the mechanical swing arm is used for measuring a target point on the space manipulator to calculate the actual lifting point position, the motion of the mechanical swing arm is corrected to eliminate the error of the lifting point position, and the error between the actual lifting point on the space manipulator and the lifting point position fed back by the space manipulator is generated due to two reasons: the position error between the omnidirectional moving platform and the six-degree-of-freedom platform is caused by the camera measurement error and the control precision of the movement of the omnidirectional moving platform following the six-degree-of-freedom platform, so that a certain deviation error is generated between the position coordinate of the space mechanical arm and the position coordinate of the mechanical swing arm; the error that space arm self flexibility produced can make and produce the error between space arm self feedback position and the actual position, and these errors finally reflect the position error between mechanical swing arm hanging point and the space arm hanging point.

In order to more fully unload the gravity of the space manipulator, through analysis, 3 lifting points are arranged on a mechanical swing arm aiming at each space manipulator, the root part of a large arm rod, an elbow joint and the tail end of a small arm of the space manipulator are respectively suspended through suspension components, wherein the tail end suspension component is provided with a multi-stage suspension component to enable two stages of joints at the tail end to be also suspended, so that the rest parts of the space manipulator except the root joint are suspended, the root joint is fixedly arranged on a simulation wall on a six-freedom-degree platform, and the gravity of the space manipulator is borne by the six-freedom-degree platform through balancing, so that the gravity of the whole space manipulator is unloaded. The joint of the suspension component and the space manipulator is designed into a multi-degree-of-freedom joint, so that the expansion motion of the manipulator can be adapted, and the suspension force is ensured to be upward.

The device that this device provided is the experimental microgravity analogue means such as space target capture, racemization is carried out on brand-new ground, compares with the experiment of going on in the past, and this application has carried out the gravity uninstallation of a plurality of hoisting points to the space manipulator for can allow the space manipulator to carry out motion on a relatively large scale in the testing process and eliminate the influence of its gravity to spacecraft attitude simulation simultaneously, make the testing process more true and accurate.

While one embodiment of the present invention has been described in detail, the description is only a preferred embodiment of the present invention and should not be taken as limiting the scope of the invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.

Claims

1. The space manipulator suspension microgravity simulation method is characterized by comprising the following steps: comprises the following steps of (a) carrying out,

2. The space manipulator suspension microgravity simulation method of claim 1, wherein: in step S1, simplifying the space manipulator that needs to unload gravity into a joint and arm rod structure of uniform mass, the space manipulator including a shoulder deflection joint, a large arm rod, an elbow joint, a small arm rod, a wrist deflection joint, a wrist rolling joint, and a tail end execution joint that are sequentially arranged and move;

3. The space manipulator suspension microgravity simulation method of claim 2, wherein: the shoulder rolling joint and the shoulder pitching joint of the space manipulator are fixed on the six-degree-of-freedom platform, the position and the posture of the space manipulator do not change relative to the six-degree-of-freedom platform in the test process, the gravity of the space manipulator is adjusted and balanced by a balance weight on the six-degree-of-freedom platform, and the suspension gravity unloading is not carried out.

4. The space manipulator suspension microgravity simulation method of claim 2, wherein: f5 ═ m2kgf, F4 ═ m1 kgf;

the moment at Fa is balanced and,

Fa＝F4+F5+G1＝13.78kgf；

calculating and determining the value of F3, wherein Fb is F3+ Fa;

moment balance at Fb, if F3 is x away from Fb and Fa is y away from Fb, then:

calculating the values of x and y to determine the position of Fb;

calculating to obtain values of F1 and F2;

5. The space manipulator suspension microgravity simulation method of claim 4, wherein: when the small arm rod of the mechanical arm rotates to form a certain angle with the large arm rod, the root joint is set as an original point, the direction of the large arm is an x axis, the vertical direction is a z axis, and the angle between the small arm and the large arm is alpha;

the x-axis moment is:

the y-axis moment is:

6. The space manipulator suspension microgravity simulation method of claim 1, wherein: the microgravity simulation device comprises 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 the air bearing platform;

7. The space manipulator suspension microgravity simulation method of claim 6, wherein: the gravity unloading and following assembly comprises 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 arranged on a mechanical swing arm support, is positioned between the two mechanical swing arms B and is used for controlling the following movement of the root lifting point of the large arm of the space manipulator;

8. The space manipulator suspension microgravity simulation method of claim 6, wherein: the following motion control of the mechanical swing arm A is divided into three stages, and the overall position of the first stage is controlled by the omnidirectional moving platform to follow the motion of the six-degree-of-freedom platform; the second stage is that the rotary arm, the linear module A and the beam form two-dimensional motion consisting of rotary motion and linear motion, and a lifting point two-dimensional control mechanism at the tail end of the swing arm A is controlled to more quickly and accurately follow the six-degree-of-freedom platform to move, so that the following motion error of the omnidirectional mobile platform is eliminated; in the third stage, the linear driving module B and the linear driving module C form a left two-dimensional motion mechanism and a right two-dimensional motion mechanism, and the two lifting points of the mechanical swing arm A are respectively controlled to move along with the lifting points of the large arm roots of the two space mechanical arms on the six-degree-of-freedom platform;

9. The space manipulator suspension microgravity simulation method of claim 6, wherein: the suspension components are three groups, are suspension components at the root part of the large arm rod and correspond to suspension points a of the space manipulator; the elbow suspension piece corresponds to a space manipulator suspension point b; the suspension parts at the tail ends of the small arms correspond to suspension points c, d and e of the space manipulator, three groups of suspension components jointly form a multi-point suspension system, the gravity of each part of the space manipulator from the root joint of the large arm rod to the execution joint part at the tail end of the manipulator is fully unloaded in the motion process, and the additional interference moment generated by the suspension force is eliminated; the large arm rod root suspension piece comprises a rolling connecting ring A; a pitching connecting shaft; an L-shaped long boom; a pin shaft A; a deflection connecting shaft A; the pin B and the lifting rope form a A, wherein the rolling connecting ring A is connected with the space manipulator and rolls and rotates around the space manipulator,

10. The space manipulator suspension microgravity simulation method of claim 9, wherein: the small arm tail end suspension piece comprises three suspension points, a rolling connecting ring C, a pitching connecting shaft C, U type long suspension claw, a deflection pin shaft and a short rod form a small arm suspension mechanism, namely a suspension point C suspension mechanism, and the suspension point C suspension mechanism has 3 degrees of freedom of rolling, pitching and deflecting, so that the small arm suspension mechanism is subjected to constant vertical suspension force equal to the required unloading gravity;