Ground simulation test method for complex operation process of multi-space robot

Abstract

The present application relates to a kind of multi-space robot complex control process ground simulation test method, the gravity compensation method of test object in it, the obstacle avoidance algorithm used in gravity compensation method, and load dynamics simulation method are defined. Including the following steps: construct global spatial coordinate system, and carry out mechanical arm dynamics simulation based on global spatial coordinate system, plan the motion trajectory of mechanical arm, according to the motion trajectory of mechanical arm, ground simulation system test is carried out.The test method of the present application realizes the six-dimensional motion adaptability of hanging gravity balance and the accuracy of air float gravity balance, and standardizes comprehensive function implementation algorithm. Thus, in the test of multi-space robot complex control process, the self gravity balance problem in the process of multi-degree-of-freedom motion of space robot is solved, and the trajectory motion problem of the mass inertia simulation gravity balance and control object is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spacecraft ground simulation test, in particular to a ground test method for complex operation process of docking mechanism, hand-eye camera, binocular camera, capture tool and multiple space manipulators with load dynamics and kinematics full physical simulation, ground cable suspension gravity balance of multiple or single space manipulators. BACKGROUND

[0002] Space manipulation is a process of capturing the target by using multiple or single space manipulator, cooperating with camera, docking mechanism and other space products, and then performing a series of operations. Large torque fluctuation of space manipulator may cause unstable control, and even lead to mission failure. It is a meaningful problem to verify the space manipulator motion combined with the dynamics characteristics of spacecraft on the ground, so as to improve the success rate of space manipulator task execution. Commonly used spacecraft ground simulation test methods include air floating test platform, water floating test platform, free fall or parabolic motion test platform, hanging tension control platform and semi-physical test platform. Air floating method uses gas pressure to float the test target spacecraft by air film, which is a high-precision microgravity environment simulation method. Its advantages are: short construction period, low cost, high precision, easy to implement and maintain; through the design of the size of the flat thrust bearing, microgravity simulation test of several tons of spacecraft can be realized, and the experimental time is not limited, through the replacement of the interface components, it can be reused, with high reliability and strong adaptability, and there is no limitation to the structure size of the spacecraft. The disadvantage is that the application of air floating in two-dimensional plane is the most common way, three-dimensional rotation air floating can be realized by using air floating ball, and vertical air floating can be realized by using air floating guide column combined with air floating pulley, but it is difficult to design six-degree-of-freedom full air floating mechanism. The advantages of water floating method are: it can realize three-dimensional space microgravity test, and the test time is not limited. Its disadvantages are: the influence of water resistance and turbulence will change the dynamics characteristics of space robot, affecting the simulation accuracy, the space robot prototype is difficult to test directly on the water floating system, and must be specially waterproofed to avoid the influence of underwater environment, and the maintenance cost is very high, and the sealing performance during the test period is required to be very good. The advantages of falling tower method are: high simulation accuracy of space microgravity environment, safety and reliability, reusability, and three-dimensional space microgravity experiment can be carried out. The disadvantages are: not only expensive, but also the size of space vehicle is limited, and the universality is poor, and more importantly, the single microgravity experiment time is too short, which cannot well evaluate the performance indicators of various devices of the spacecraft, so that its application in space robot is greatly limited. The main principle of suspension method is to use counterweight to offset the gravity of spacecraft or active gravity compensation through rope mechanism and pulley group. The advantages of suspension method are: three-dimensional space simulation can be carried out, the structure is relatively simple, easy to implement, and the experimental time is not limited, so it is widely used at present. Its defects are: the truss mechanism supporting the rope is complex, occupies a large space, and can only be used to test light spacecraft. Semi-physical simulation combines mechanical system with digital to simulate real docking motion, which has the flexibility of digital simulation and the reality of physical simulation. The disadvantage is that due to the measurement delay of force measurement sensor and the response delay of motion simulator, semi-physical simulation system will produce time lag, which will lead to instability and distortion of the system, and even divergence, which needs to be compensated by algorithm. SUMMARY

[0003] The present application aims to provide a multi-space robot complex operation process ground simulation test method, which specifies the space manipulator active gravity compensation and the manipulator air floating load rudder wheel driving algorithm. The present application designs the active hanging form for the space manipulator gravity compensation, the air floating method for the manipulator load dynamics simulation, and the active hanging algorithm and the simulation driving algorithm used in the form of the rudder wheel driving of the air floating platform simulation piece.

[0004] The technical scheme adopted by the present application to achieve the above-mentioned purpose is:

[0005] The multi-space robot complex operation process ground simulation test method comprises the following steps:

[0006] A global space coordinate system is constructed, and the manipulator dynamics simulation is carried out based on the global space coordinate system, the motion trajectory of the manipulator is planned, and the ground test is carried out according to the motion trajectory of the manipulator.

[0007] The global space coordinate system is constructed, specifically:

[0008] The observable point in the support unit is taken as the origin of the absolute coordinate system, the vertical direction is the y direction, the horizontal direction is the x direction along the main motion direction, and the secondary motion direction is the z direction.

[0009] The ground test according to the motion trajectory of the manipulator comprises the following steps:

[0010] The suspended gravity balance unit is moved to the y direction of the global space coordinate system by the manipulator, and the gravity balance test of the ground simulation system is carried out;

[0011] The suspended gravity balance unit is moved to the zx direction of the global space coordinate system by the manipulator, and the zx direction obstacle avoidance test of the ground simulation system is carried out;

[0012] The rudder turning angle, turning speed and driving speed of the air floating simulation piece composed of the target star simulation unit and the control satellite simulation unit are tested;

[0013] After the test is completed, the suspended gravity balance unit is reset and the ground simulation system is removed.

[0014] The gravity balance test comprises the following steps:

[0015] In the y freedom direction, the wire rope tension is detected by the force sensor arranged in the hanging mechanism, the difference between the set value and the wire rope tension is controlled by the force feedback, and the wire rope tension is set to the set value.

[0016] When the suspension gravity balance unit moves along the zx direction, the wire rope inclination angle of the suspension gravity balance unit is controlled by respectively arranging the Z direction and X direction drivers on the suspension gravity balance unit, so that the wire rope is always kept vertical to the ground.

[0017] The zx direction obstacle avoidance test is specifically:

[0018] The distance between the cross beams and the moving frame in the suspension gravity balance unit is acquired in real time, and when the distance between the cross beams meets the moving frame collision condition, the logical protection boundary is obtained based on the minimum distance between the moving frames, and the cross beam collision prediction result is obtained according to the logical protection boundary.

[0019] The test of the rudder wheel steering angle, steering speed and driving speed in the air float simulation piece is specifically:

[0020] The air float simulation piece respectively performs the operations of lifting the rudder wheel, rotating the rudder wheel, lowering the rudder wheel and lifting the brake, so as to capture the target; the motion trajectory of the simulation piece is planned in real time, the trajectory is calculated as the rudder wheel motion trajectory of the simulation piece, the steering angle, steering speed and driving speed of the two rudder wheels are calculated in real time, and the rudder wheel is driven to steer and move by the motor, so as to drive the simulation piece to perform according to the motion trajectory.

[0021] The space control full physical test system is tested, and the space control full physical test system can adopt the following technical scheme, which comprises a target satellite simulation unit, a control satellite simulation unit and a space mechanical arm, and the control satellite simulation unit is provided with a space mechanical arm on one side, comprises a frame body, a suspension balance gravity unit and a supporting unit, wherein the supporting unit is arranged in the frame body, a smooth platform is arranged in the middle of the supporting unit, the lower ends of the target satellite simulation unit and the control satellite simulation unit are respectively supported by corresponding air float units, the air float units are movably arranged on the smooth platform, the suspension balance gravity unit is movably arranged on the upper side of the frame body, a moving frame is arranged on the lower side of the suspension balance gravity unit, a movable hanging mechanism is arranged on the lower side of the moving frame, and the hanging mechanism is connected with the space mechanical arm through a lifting wire rope.

[0022] The hanging mechanism comprises a hanging moving seat, a winch, an electric cylinder, a fixed pulley, a movable pulley and a wire rope, wherein the upper end of the hanging moving seat is slidably connected with the moving frame, the winch, the electric cylinder, the fixed pulley and the movable pulley are arranged in the hanging moving seat, the fixed pulley is fixedly arranged in the hanging moving seat, the movable pulley is vertically moved by the electric cylinder, one end of the wire rope is wound on the winch after passing through the fixed pulley and the movable pulley in sequence, and the other end of the wire rope is connected with the space mechanical arm after extending out of the hanging moving seat.

[0023] The suspension counterweight gravity unit is provided with a cross beam, the upper side of the moving frame is in sliding connection with the cross beam, the cross beam is provided with a moving frame driving rack, the upper side of the moving frame is provided with a moving frame driving motor, and the output shaft of the moving frame driving motor is provided with a moving frame gear in engagement with the moving frame driving rack.

[0024] The two ends of the cross beam are provided with cross beam moving seats in sliding connection with the side beams of the corresponding sides of the frame body, the side beams of the frame body are provided with cross beam moving racks, the cross beam moving seats are provided with cross beam driving motors, and the output shafts of the cross beam driving motors are provided with cross beam driving gears in engagement with the cross beam moving racks.

[0025] The lower side of the air floating unit is provided with a driving wheel rolling along the smooth platform, the upper side of the air floating unit is provided with a laser ranging sensor, the periphery of the supporting unit is provided with a raised plate, and the inner side of the raised plate is provided with a reflecting plate, the signal emitted by the laser ranging sensor is reflected by the reflecting plate and returned to the system sensor.

[0026] The lower side of the supporting unit is provided with an adjustable supporting device for adjusting the level.

[0027] The adjustable supporting device comprises a base, a screw rod, a locking nut and a top block, the lower end of the screw rod is in threaded connection with the upper end of the base and is locked by the locking nut, and the upper end of the screw rod is provided with the top block.

[0028] The air floating unit is provided with an air floating assembly, and an air film is formed between the air floating assembly and the smooth platform.

[0029] The air floating assembly comprises a bottom plate, a top plate, an air foot screw rod and an air foot spring, the air foot screw rod is arranged between the bottom plate and the top plate, the air foot spring is sleeved on the air foot screw rod, the bottom of the bottom plate is provided with an air hole, and the upper side of the bottom plate is connected with compressed air.

[0030] The air floating unit comprises an air floating base, a driving wheel arranged on the lower side of the air floating base, an air floating assembly and a braking chuck.

[0031] The present application has the following advantages and benefits:

[0032] 1. The test method of the present application realizes the six-dimensional motion adaptability of the hanging gravity balance and the accuracy of the air floating gravity balance, and standardizes the comprehensive function implementation algorithm.

[0033] 2, The application utilizes the quick response of vertical movement to realize high-precision gravity balance control of the space robot under the condition of having a vertical movement speed component. The movement characteristics of the two execution mechanisms are fully utilized, the electric cylinder has quick response capability, but does not have large-stroke movement characteristics; the winch mechanism can realize large-stroke movement, and has weak quick response capability. The algorithm of the application fully combines the advantages of the winch mechanism and the electric cylinder, and realizes large-range fast dynamic gravity balance.

[0034] 3, The application utilizes inclination detection to realize vertical retention of the steel wire rope, thereby realizing horizontal movement following of the space robot. The method of combining the cross beam and the moving frame is utilized to realize large-range movement while meeting the fine movement between different suspension points. For the collision problem in the large-range movement process, logical collision prediction and autonomous obstacle avoidance strategy are realized. The automatic tracking of the space robot movement of the suspension point in the test process can be met, the operator does not need to plan the trajectory in advance, and the operation convenience is greatly improved.

[0035] 4, The application realizes switching of trajectory movement and free movement of the large-range air-floating mass inertia simulation piece with autonomous power. The cooperative and non-cooperative movement of the air-floating simulation piece as the operation target is realized. Rich space control movement simulation movement is realized. Flexible setting of the space control movement is realized. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a three-dimensional schematic view of the application;

[0037] Figure 2 It is a front view of the application;

[0038] Figure 3 It is a suspension balance gravity unit structure schematic view in Figure 1

[0039] Figure 4 It is a hanging mechanism structure schematic view in Figure 3

[0040] Figure 5 It is a hanging mechanism side view in Figure 4

[0041] Figure 6 It is a support unit structure schematic view in Figure 1

[0042] Figure 7 It is an adjustable support device structure schematic view in Figure 6

[0043] Figure 8 It is a control satellite simulation unit structure schematic view in Figure 1

[0044] ​​​​​​Figure 9 is a schematic view of the air floating unit structure in Figure 8

[0045] Figure 10 is a schematic view of the air floating assembly structure in Figure 9

[0046] Figure 11 is a schematic view of the space mechanical arm structure in Figure 2

[0047] Figure 12 is a schematic view of the target satellite simulation unit structure in Figure 1

[0048] Figure 13 is a simulation interest coordinate system of the application

[0049] Figure 14 is a vertical gravity balance diagram of the application

[0050] Figure 15 is an algorithm block diagram

[0051] Figure 16 is a steering wheel schematic diagram of the air floating system drive of the application

[0052] Figure 17 is a test step block diagram of the application

[0053] Figure 18 is a function block diagram of the application

[0054] Wherein, 1 is a suspension balance gravity unit, 101 is a hanging mechanism, 1011 is a hanging moving seat, 1012 is a winch, 1013 is an electric cylinder, 1014 is a fixed pulley, 1015 is a movable pulley, 1016 is a steel wire rope, 1017 is a hanging drive motor, 102 is a moving frame, 1021 is a moving frame drive motor, 1022 is a gear, 1023 is a moving frame sliding block, 1024 is an upper mounting plate, 1025 is a lower mounting plate, 1026 is a control box, 103 is a cross beam, 104 is a cross beam moving seat, 2 is a support unit, 201 is an adjustable support device, 2011 is a base, 2012 is a locking nut, 2013 is a screw rod, 2014 is a top block, 202 is a smooth platform, 203 is a reflector, 3 is a space mechanical arm, 4 is a target satellite simulation unit, 401 is a second stand, 5 is a control satellite simulation unit, 501 is a first stand, 502 is a mechanical arm support frame, 6 is a frame body, 7 is an air floating unit, 701 is a support plate, 702 is an air floating base, 703 is a laser ranging sensor, 704 is an air floating assembly, 7041 is a top plate, 7042 is an air foot screw rod, 7043 is an air foot spring, 7044 is a bottom plate, 705 is a buffer spring, 706 is a drive wheel, and 707 is a brake suction cup. ​​​​DETAILED DESCRIPTION

[0055] The application will be further described in detail below in combination with the drawings and examples.

[0056] As shown in the drawings, Figures 1 to 12 The application includes a frame 6, a suspended balanced gravity unit 1, a support unit 2, a target satellite simulation unit 4, a satellite simulation unit 5, and a space mechanical arm 3, wherein the support unit 2 is arranged inside the frame 6, and as shown in the drawings, Figure 6 The middle part of the support unit 2 is provided with a smooth platform 202, and the periphery is provided with a light-reflecting plate 203, as shown in the drawings, Figure 8 And Figure 12 The lower end of the target satellite simulation unit 4 and the lower end of the satellite simulation unit 5 are respectively supported by corresponding air floating units 7, and the air floating units 7 are movably arranged on the smooth platform 202, as shown in the drawings, Figure 2 One side of the satellite simulation unit 5 is provided with a space mechanical arm 3, the suspended balanced gravity unit 1 is movably arranged on the upper side of the frame 6, and as shown in the drawings, Figures 3 to 4 The lower side of the suspended balanced gravity unit 1 is provided with a moving frame 102, the lower side of the moving frame 102 is provided with a movable hanging mechanism 101, and the hanging mechanism 101 is connected with the space mechanical arm 3 through a liftable steel wire rope 1016.

[0057] When the application works, the satellite simulation unit 5 on the smooth platform 202 in the middle part of the support unit 2 simulates a stable target in a space weightlessness environment, while the target satellite simulation unit 4 simulates an unstable target in a space weightlessness environment, the satellite simulation unit 5 uses the space mechanical arm 3 to control the target satellite simulation unit 4, and then completes the space task, and the suspended balanced gravity unit 1 and the air floating unit 7 realize the simulation of the space microgravity environment of the satellite simulation unit 5, the target satellite simulation unit 4, and the space mechanical arm 3.

[0058] As shown in the drawings, Figure 3 The suspended balanced gravity unit 1 is provided with a crossbeam 103, and the two ends of the crossbeam 103 are provided with crossbeam moving seats 104 which are respectively slidably connected with the side beams on the corresponding sides of the frame 6, in this embodiment, a crossbeam driving motor is arranged on the crossbeam moving seat 104, a crossbeam driving gear is arranged on the output shaft of the crossbeam driving motor, a crossbeam moving slide rail and a crossbeam moving rack are arranged on the side beams of the frame 6, a crossbeam moving slide block is arranged on the lower side of the crossbeam moving seat 104 and matched with the crossbeam moving slide rail, and the crossbeam driving gear is engaged with the crossbeam moving rack. The crossbeam driving motor drives the crossbeam 103 to move through the crossbeam moving gear and the crossbeam moving rack.

[0059] The lower side of the crossbeam 103 is provided with a moving frame slide rail and a moving frame driving rack, as shown in the drawings, Figure 4As shown, the mobile frame 102 is provided with a mobile frame driving motor 1021 and a mobile frame slider 1023 on the upper side, wherein the mobile frame slider 1023 is hung and matched with the mobile frame slide rail on the corresponding side to realize the sliding connection of the mobile frame 102 and the cross beam 102, and the output shaft of the mobile frame driving motor 1021 is provided with a mobile frame driving gear matched with the mobile frame driving rack, and the mobile frame driving motor 1021 drives the mobile frame 102 to move through the transmission of torque by the mobile frame driving gear and the mobile frame driving rack.

[0060] As shown in Figure 4 , the mobile frame 102 is provided with an upper mounting plate 1024, and the mobile frame driving motor 1021 and the mobile frame slider 1023 are arranged on the upper mounting plate 1024, and the mobile frame 102 is provided with a lower mounting plate 1025 on the lower side, and the hanging mechanism 101 is movably arranged on the lower mounting plate 1025, as shown in Figure 5 , one side of the mobile frame 102 is provided with a control box 1026 accommodating a control system module.

[0061] As shown in Figure 4 , the hanging mechanism 101 includes a hanging mobile seat 1011, a winch 1012, an electric cylinder 1013, a fixed pulley 1014, a movable pulley 1015 and a steel wire rope 1016, wherein the upper end of the hanging mobile seat 1011 is in sliding connection with the lower mounting plate 1025 of the mobile frame 102, the winch 1012, the electric cylinder 1013, the fixed pulley 1014 and the movable pulley 1015 are arranged in the hanging mobile seat 1011, wherein the fixed pulley 1014 is fixedly arranged in the hanging mobile seat 1011, and the movable pulley 1015 is driven to move vertically by the electric cylinder 1013, one end of the steel wire rope 1016 is wound on the winch 1012 after passing through the fixed pulley 1014 and the movable pulley 1015 in sequence, and the other end of the steel wire rope 1016 extends out of the hanging mobile seat 1011 and is connected with the space mechanical arm 3. The present application realizes the accurate balance of the steel wire rope 1016 to the gravity of the space mechanical arm 3 by adjusting the rotation of the winch 1012 and the extension of the electric cylinder 1013, the fixed pulley 1014 is installed on a force sensor, the tension of the steel wire rope 1016 can be obtained in real time, the system controls the extension of the steel wire rope 1016 according to the force value measured by the force sensor, so as to improve the gravity balance accuracy of the space mechanical arm 3. The force sensor is a commercially available product.

[0062] As shown in Figures 4 to 5As shown, the lower mounting plate 1025 of the movable frame 102 is provided with a hanging sliding rail and a hanging drive rack on its lower side. The upper end of the hanging moving seat 1011 is provided with a hanging slider that cooperates with the corresponding hanging sliding rail to achieve a sliding connection between the hanging moving seat 1011 and the lower mounting plate 1025. A hanging drive motor 1017 is provided on one side of the hanging moving seat 1011, and a hanging drive gear is provided on the output shaft of the hanging drive motor 1017 that cooperates with the hanging drive rack. This invention enables the movement of the crossbeam 103, the movable frame 102, and the hanging moving seat 1011, as well as the up-and-down movement of the wire rope 1016, to move with the space robotic arm 3. Through the designed motion control strategy, the tension of the wire rope 1016 is always equal to the weight of the space robotic arm 3, that is, the weight of the space robotic arm 3 is balanced.

[0063] like Figure 6 As shown, in this embodiment, the smooth platform 202 is made of seamless granite, such as... Figures 8 to 9 and Figure 12 As shown, the air-bearing unit 7 is equipped with drive wheels 706 that can roll along the smooth platform 202, thereby enabling the target satellite simulation unit 4 and the control satellite simulation unit 5 to move on the smooth platform 202. The air-bearing unit 7 is equipped with a laser rangefinder 703. The support unit 2 has raised plates around its perimeter, and a reflector 203 is located on the inner side of each raised plate. The signal emitted by the laser rangefinder 703 is reflected back to the system sensor via the reflector 203, thereby determining the position information of each satellite simulation unit. The laser rangefinder 703 is a commercially available product.

[0064] like Figures 6 to 7 As shown, the lower side of the support unit 2 is provided with an adjustable support device 201 to ensure that the smooth platform 202 is level. In this embodiment, the adjustable support device 201 includes a base 2011, a screw 2013, a locking nut 2012 and a top block 2014. The lower end of the screw 2013 is threadedly connected to the upper end of the base 2011 and locked by the locking nut 2012. The upper end of the screw 2013 is provided with a top block 2014 to support the support unit 2. The screw 2013 can be rotated to raise and lower to achieve leveling of the support unit 2.

[0065] like Figure 9As shown in the figure, the air floating unit 7 comprises an air floating base 702, a driving wheel 706, an air floating assembly 704 and a brake suction disc 707, wherein the air floating base 702 is provided with a support plate 701 on the upper side and is connected with the corresponding satellite simulation unit, the air floating base 702 is provided with a laser ranging sensor 703 around, the air floating base 702 is provided with the driving wheel 706, the air floating assembly 704 and the brake suction disc 707 on the lower side, wherein the wheel frame of the driving wheel 706 is connected with the upper beam of the air floating base 702 through a connecting shaft, the connecting shaft is provided with a buffer spring 705, the driving wheel 706 is provided with a motor drive rotation, so as to realize the movement of the corresponding simulation unit, and the brake suction disc is connected with a vacuum device arranged in the air floating base 702 to realize adsorption on the smooth platform 202 and positioning.

[0066] As shown in the figure, Figure 10 As shown in the figure, the air floating assembly 704 comprises a bottom plate 7044, a top plate 7041, an air foot screw 7042 and an air foot spring 7043, wherein the air foot screw 7042 is arranged between the bottom plate 7044 and the top plate 7041, the air foot spring 7043 is sleeved on the air foot screw 7042 and abuts against the bottom plate 7044 and the top plate 7041 at both ends, the bottom plate 7044 is provided with a plurality of small air holes at the bottom, and the bottom plate 7044 is provided with an air pipe at the upper side for inputting compressed air, and the compressed air is sprayed out from the small air holes at the lower side of the bottom plate 7044, the reaction force of the gas is utilized to form a gas gap of about 0.03mm between the air floating assembly 704 and the smooth platform 202, so as to realize the floating of the satellite simulation unit, and at this time, the driving wheel 706 is separated from the smooth platform 202. The air floating base 702 is provided with a compressed air generating device, which is a commonly known technology in the art and a commercially available product.

[0067] As shown in the figure, Figure 11 As shown in the figure, the space mechanical arm 3 of the embodiment adopts a 7-degree-of-freedom mechanical arm, which comprises a shoulder joint, an elbow joint, a wrist joint and the like, and the space mechanical arm 3 is a commonly known technology in the art.

[0068] As shown in the figure, Figure 8 As shown in the figure, the control satellite simulation unit 5 is provided with a first stand 501 installed on the corresponding air floating unit 7, and the outer side of the shell of the control satellite simulation unit 5 is provided with a mechanical arm support frame 502 for installing the space mechanical arm 3. The control satellite simulation unit 5 is a commonly known technology in the art.

[0069] As shown in the figure, Figure 12 As shown in the figure, the target satellite simulation unit 4 is provided with a second stand 401 installed on the corresponding air floating unit 7, and the outer side of the second stand 401 is provided with a cover plate to make the appearance same as the real satellite. The target satellite simulation unit 4 is a commonly known technology in the art, which can realize six-degree-of-freedom movement.

[0070] The working principle of the application is as follows:

[0071] When the system is running, the suspension gravity balance unit 1 balances the gravity of the space manipulator 3, and the air floating unit 7 balances the gravity of the target satellite simulation unit 5 and the operating satellite simulation unit 4 in cooperation with the smooth platform 202 of the support unit 2, so as to realize the purpose of simulating the microgravity environment. In the above microgravity environment, the operating satellite simulation unit 5 operates the target satellite simulation unit 4 through the 7-degree-of-freedom space manipulator 3, including cooperative target capture, positioning and parking, double-arm cooperative fine operation, unstable target single / double-arm capture braking, stable target nozzle capture and other experiments, so as to verify the kinematics and dynamics characteristics of the operating satellite simulation unit 5, the target satellite simulation unit 4 and the space manipulator 3, as well as the control algorithm of the 7-degree-of-freedom space manipulator 3 and the relative navigation and image recognition algorithm.

[0072] Specifically as follows:

[0073] Step one: kinematics and dynamics analysis is performed on the multi-body system composed of the target satellite simulation unit 5, the operating satellite simulation unit 4 and the space manipulator 3, so as to obtain the motion trajectory of the space manipulator 3 when completing cooperative target capture, positioning and parking, double-arm cooperative fine operation, unstable target single / double-arm capture braking, stable target nozzle capture and other tasks.

[0074] Step two: the three-dimensional motion trajectory of the hanging mechanism 101 connected with the space manipulator 3 and the motion trajectory of the operating satellite simulation unit 4 and the target satellite simulation unit 5 on the support unit 2 are obtained through the motion trajectory of the space manipulator 3 obtained in step one.

[0075] Step three: according to the trajectory obtained in step two, the motion strategy design is performed on the cross beam 103, the moving frame 102 in the suspension gravity balance unit 1 and the hanging moving seat 1011 in the hanging mechanism 101, so that the hanging mechanism 101 cooperates with the motion of the space manipulator 3 and does not interfere with each other, and the target satellite simulation unit 5 is controlled to complete the space six-degree-of-freedom motion.

[0076] Step four: the control strategy of the cross beam 103 and the hanging mechanism 101 and the following strategy of the target satellite simulation unit 5 are debugged, so as to realize the interference avoidance optimization among objects.

[0077] In the above process, according to the kinematics and dynamics analysis of the space manipulator 3, the present application realizes the precise balance of the gravity of the space manipulator 3 by the control of the winch 1012 and the electric cylinder 1013 in the hanging mechanism 101, and realizes the balance of the gravity of the corresponding satellite simulation unit by the air film formed between the air floating assembly 704 and the smooth platform 202 of the support unit 2, and the smooth platform 202 needs to be ensured to be horizontal to realize air floating, once the simulation unit is air floated, the simulation unit moves to one side due to the loss of friction between the simulation unit and the smooth platform 202 when the smooth platform 202 is inclined, and the experimental purpose cannot be achieved, therefore, the present application sets the adjustable support device 201 on the lower side of the support unit 2 to ensure the horizontal of the support unit 2, and meets the experimental requirements.

[0078] The present application utilizes the steel wire rope of the hanging mechanism and the space manipulator to balance the gravity of the space manipulator, and utilizes the air film formed between the air floating assembly in the air floating unit and the smooth platform of the support unit to balance the gravity of the satellite simulator, so that the space weightlessness environment is simulated, and the technical innovation of the space robot is verified.

[0079] The crossbeam, the moving frame in the suspension gravity balance unit and the hanging moving seat in the hanging mechanism can realize the multiple free movement of the steel wire rope, can follow the movement of the space manipulator, and the winch and the electric cylinder in the hanging mechanism control the expansion and contraction of the steel wire rope, so that the tension of the steel wire rope can accurately balance the gravity of the space manipulator.

[0080] The air floating unit is provided with a driving wheel and a brake suction cup, so that the satellite simulation unit is convenient to move and fixedly brake.

[0081] The smooth platform 202 of the support unit needs to be ensured to be horizontal to realize the air floating of the satellite simulation unit, therefore, the present application sets the adjustable support device on the lower side of the support unit 2 to ensure the horizontal of the support unit 2, and meets the experimental requirements.

[0082] A global space coordinate system is established: the observable point in the support unit is selected as the origin of the absolute coordinate system, the vertical direction is the y direction, the horizontal direction is the x direction along the main movement direction, and the secondary movement direction is the z direction. All discussions are based on the absolute coordinate system. The discussions include the hanging point movement of the hanging gravity balance system, the movement of the space robot, the attitude of the space robot load-air floating mass inertia simulation piece, the trajectory movement of the air floating simulation piece, the discussion of the space operation cooperative target and the non-cooperative target. The space global absolute coordinate system of the suspension gravity balance unit is memorized by the absolute encoder in the hardware, the global coordinate system of the air floating system is memorized by the laser radar and the fixed target, and the attitude of the cooperative and non-cooperative target is obtained by the laser radar coordinate folding of the air floating system.

[0083] Mechanical arm dynamics simulation: Before the establishment of the test system, the dynamics of the tested mechanical arm and the tested load satellite are simulated. The simulation purpose is to plan the motion trajectory of the space mechanical arm operation process, theoretically check whether the trajectory exists interference, theoretically check whether the mechanical arm output is sufficient, provide the required hanging force for the mechanical arm gravity unloading, and verify whether the suspension gravity balance unit has sufficient working range. According to the kinematic examples of some tasks in the operation test, some problems existing in the operation of the space mechanical arm are focused on the ability of the mechanical arm to overcome the disturbance of environmental changes, the fluctuation of the desired torque of the joint, and whether the motion is smooth and other factors. The kinematic model of the task is constructed, and then the trajectory suitable for the current task is obtained according to the current environment regression. This strategy can quickly generate the current task trajectory and avoid the control instability phenomenon caused by large torque fluctuation of the space mechanical arm. After the simulation system is successfully built, for other types of tasks, only the corresponding kinematic examples need to be input to perform simulation operation, which greatly simplifies the operation.

[0084] Suspension gravity balance unit y degree of freedom direction driving algorithm: The y degree of freedom direction motion is vertical direction motion, and the significance of vertical direction motion is to maintain the hanging force at a set value while following the vertical motion of the mechanical arm. The specific method is that the steel wire rope retraction and release works in position mode, and the retraction and release of the steel wire rope is controlled through force feedback algorithm to maintain the steel wire rope tension at a set value. The retraction and release of the steel wire rope has two sets of actuators, which are connected in series. Any movement of the two actuators can cause the retraction and release of the steel wire rope, and the movement of the two actuators can be superimposed. Therefore, the coordination of the two actuators in the vertical direction needs to be considered in the gravity balance algorithm.

[0085] Suspension gravity balance unit ZX direction degree of freedom driving algorithm: Z direction and X direction are in the horizontal plane, and a steel wire rope inclination feedback controller is designed to maintain the steel wire rope vertical. When the steel wire rope has an angle with the vertical direction due to the movement of the mechanical arm, the Z and X direction drivers of the suspension gravity balance unit are driven according to the balance algorithm to maintain the steel wire rope vertical.

[0086] Suspension gravity balance unit ZX direction obstacle avoidance strategy: Due to the design of the mechanism, the suspension gravity balance unit itself is prone to collision. The X degree of freedom direction of the suspension gravity balance unit has two sets of actuators, which are the crossbeam and the moving frame. The crossbeam can drive the suspension point to realize large-range motion in the whole stroke, and the moving frame can realize the close proximity between the suspension points. The moving frame is bound to move in the Z direction, so when the two adjacent crossbeams are close to a certain distance, the moving frame has the risk of collision. The autonomous avoidance strategy needs to calculate the distance between the crossbeams in real time, and when the distance between the crossbeams meets the moving frame collision condition, the boundary condition is combined with the distance between the moving frames to judge the boundary condition. The boundary condition is calculated through logical operation to obtain the crossbeam collision prediction result. Dynamic boundary condition calculation is also needed during collision prediction. The calculation result of the dynamic boundary condition is also involved in the logical operation to generate the collision condition.

[0087] Air float simulation piece radar positioning algorithm: This method uses a laser radar fixed above the air float simulation piece to scan the reflective targets fixed around the test device, calculates the distance between the current position and multiple targets, solves the attitude equation, and obtains the three degrees of freedom attitude in the plane of the current radar. The process of applying radar positioning first needs to be calibrated. Although the radar calculation result only has three degrees of freedom attitude relationship in the horizontal plane, the calibration process still needs to calibrate the six degrees of freedom attitude relationship between the radar coordinate system and the target. Because in the process of large-scale positioning, the small attitude inclination of the radar will bring a large measurement error. The calibration process includes the solving parameters of the radar coordinate system and the global coordinate system, and the conversion relationship between the radar coordinate system and one or more interest coordinate systems fixed on the simulation piece. If there is a motion link between the interest coordinate system fixed on the simulation piece and the radar coordinate system, the motion link measurement zero point and the motion link measurement accuracy also need to be calibrated. After calibration, the radar is used to obtain the attitude of the radar coordinate system in the global coordinate system in real time, and then the attitude of the interest coordinate system in the global coordinate system is solved according to the conversion relationship between the radar coordinate system and the interest coordinate system.

[0088] Air-floating simulator steering wheel drive algorithm: The air-floating simulator floats on an air-floating platform using air buoyancy. When the brake cylinder is lifted, the air-floating simulator can move freely on the air-floating platform. The air-floating simulator drive program includes steering wheel lifting control, steering wheel and air-floating platform positive pressure control, steering wheel steering control, and steering wheel drive control. Steering wheel lifting control drives the steering wheel up and down. When the simulator needs to operate in free motion mode, the steering wheel rises; when the simulator needs to operate in active motion mode, the steering wheel is lowered via a lifting device. Simultaneously, the steering wheel and air-floating platform positive pressure control maintains the positive pressure between the steering wheel and the air-floating platform within the required range, allowing the simulator to be driven by the steering wheel movement. Each air-floating simulator has two steering wheels capable of 360-degree rotation. When driving the simulator, the simulator's motion trajectory is planned in real time, calculated into the steering wheel motion trajectory, and driven by the motor to steer and move the steering wheels, thus causing the simulator to execute according to the motion trajectory.

[0089] Wireless Communication Algorithm: To reduce interference from cables on the air-float simulator, the simulator communicates with the ground-based main control computer wirelessly. Wireless communication is achieved through a wireless access point (AP), which transmits TCP protocol communication signals. These signals are then transmitted via a wireless network to the test equipment's local area network (LAN) to enable communication between devices. The wireless communication algorithm of this test platform specifies the content, data format, and communication cycle for each simulator's communication with the main control computer. The algorithm also specifies the data transmission between the test simulator and the aerospace products mounted on the simulator.

[0090] This invention provides a ground simulation test method for complex maneuvering processes of multi-space robots.

[0091] Step 1: Before conducting ground simulation tests of complex maneuvering processes of multi-space robots, a series of preparatory work needs to be done, including equipment status self-check, space robot gravity balance simulation, space robot maneuvering process simulation, space robot maneuvering object simulation, space robot maneuvering object trajectory planning, test fault handling plan, test job division, and test document preparation.

[0092] Step 1.1: The self-test of the test equipment needs to check whether the equipment can be powered on and started normally, and whether the equipment movement and display are consistent. Figure 2 The global coordinate system definition is shown. Check if the device software provides it. Figure 13 The pose of the interest coordinate system shown is in the global coordinate system.

[0093] Step 1.2: Before testing, determine the balancing forces of the space robot that need to be used in the test process through simulation.

[0094] Step 1.3: Before conducting spatial manipulation tests, determine the motion path of the space robot through simulation, such as...Figure 15 Observe whether there is interference between the space robot and the space robot itself, the space robot and the tool, the tool and the tool during the operation.

[0095] Step 1.4: Before the test, determine whether the mass inertia of the operation object can be within the load capacity range of the space robot by simulating the operation object. Ensure that the space robot does not have excessive joint torque during the operation verification.

[0096] Step 1.5: Before the test, plan the trajectory of the space robot operating the non-cooperative target, determine the target motion path, select the test area, and determine that the test bed stroke meets the test requirements.

[0097] Step 1.6: Formulate a fault handling plan for the test before the test, standardize the handling method for common faults during the test, such as the handling method for power failure and gas failure during the test; the handling method for excessive or insufficient pulling force caused by motor out of control during the test; how to continue the test after the test is paused, if the test needs to be paused overnight, how to protect at night; how to handle personnel casualties during the test, etc.

[0098] Step 1.7: The test post division should be determined before the test. Clearly define the test commander, responsible for issuing orders and overall control of the test; test operators are divided into test equipment operators and measured equipment operators, each post should have A and B positions; the test safety observer post is responsible for observing the fault points prone to occur during the test.

[0099] Step 1.8: Test document preparation should be done to specify each step of operation, all documents before the test should be signed, and all documents present in the test site should be controlled.

[0100] Step 2: Before the test starts, move the test system hanging device to the initial state; move the test measured equipment and simulation assembly to the initial state.

[0101] Step 2.1: Move the hanging device used in the test to the initial position given by the simulation, which is the initial position of the measured robot transferred from the air floating support to the hanging force balance.

[0102] Step 2.2: Move the unused hangers to an area that does not affect the test, and ensure that the unused hangers do not cause logical collisions when the cross beam approaches.

[0103] Step 2.3: The initial state of the lifting point used in each test contains the initial position of the five motors, which need to be moved to the coordinate points given by the absolute encoder, wherein the initial state of the electric cylinder is generally 0 point, the initial state of the X freedom moving frame is the theoretical position given by the simulation, and meets the X initial position given by the simulation by adding the position of the crossbeam. The rest of the motors are moved to the initial position given by the simulation.

[0104] Step 2.4: Move the air floatation simulation device to the initial attitude given by the simulation.

[0105] Step 3: Before the test starts, the space robot to be tested needs to be hung on the lifting device.

[0106] Step 3.1: Loosen the pressure seats in sequence, and install the wrist joint support tooling at the pressure seat installation position.

[0107] Step 3.2: Loosen the pressure seats in sequence, and install the elbow joint support tooling at the pressure seat installation position.

[0108] Step 3.3: Loosen the remaining pressure seats that need to be loosened, start the air floatation, and measure the levelness and parallelism of the space robot arm, if the height difference is greater than 0.1 mm, adjust the air floatation tooling to make the height difference less than 0.1 mm.

[0109] Step 3.4: Move the tested space robot according to the specified motion, and measure the height difference of the arm at each stop point.

[0110] Step 3.5: When the tested robot reaches the switching position, connect the lifting tooling with the lifting point. Apply the lifting force, and after reaching the simulation value, loosen the connection between the air floatation support tooling and the tested robot, and remove the tooling.

[0111] Step 4: In the lifting state, move the space robot to the initial configuration of the capture operation, and start the control test.

[0112] Step 4.1: The lifting device is in a force balance state, at this time the vertical direction of the lifting device is in the working state as shown in Figure 14 The No. ① pulley has a force sensor to measure the tension of the steel wire rope, the No. ② pulley is a dynamic pulley that quickly executes a gravity balance algorithm, and the No. ③ pulley maintains the No. ② pulley near the balance position and executes an auxiliary gravity balance algorithm.

[0113] Step 4.2: Figure 16 The horizontal following function of the large range lifting device is started at the same time, and the steel wire rope is kept in a vertical state according to the inclination angle of the steel wire rope. During the movement, the lifting device may produce collisions as shown in Figure 17 These collisions are predicted according to the method shown in Figure 18 The avoidance request generated by the prediction algorithm is executed according toFigure 18 The calculated path is shown to the execution mechanism to execute active obstacle avoidance.

[0114] Step 4.3: The space manipulator performs target capture and positioning operations according to the established action during the test.

[0115] Step 5: After the space control test is completed, the device is reset.

[0116] Step 5.1: First, separate the tested space manipulator from the capture target.

[0117] Step 5.2: Move the manipulator to the conversion configuration with the help of the hanger.

[0118] Step 5.3: Drive the simulation piece to the parking position through the steering wheel, apply the brake after it is in place, raise the steering wheel, and close the air foot.

[0119] Step 5.4: Connect the air floating support tool to the manipulator at the conversion position, and after the connection is completed, gradually unload the hanger force.

[0120] Step 5.5: When the hanger force is unloaded to below 50N, the lifting point exits the force control mode, the drive motor releases the hanger tool, and the hanger tool is removed. The lifting point moves to the parking position.

[0121] Step 5.6: Drive the space manipulator to the compression state, install the compression seat in sequence, and gradually remove the air floating tool until all the compression seats are installed in place. The test is completed.

Claims

1. A ground simulation test method for complex manipulation processes of multi-space robots, characterized in that, Includes the following steps: Construct a global spatial coordinate system, perform dynamic simulation of the robotic arm based on the global spatial coordinate system, plan the motion trajectory of the robotic arm, and conduct ground tests based on the motion trajectory of the robotic arm; The ground test based on the movement trajectory of the robotic arm includes the following steps: The suspended gravity balance unit is moved in the y direction of the global spatial coordinate system by a robotic arm to perform a gravity balance test on the ground simulation system. The suspended gravity balance unit is moved in the zx direction of the global spatial coordinate system by a robotic arm to conduct obstacle avoidance test in the zx direction on the ground simulation system; The steering wheel angle, steering speed, and drive speed in the air-bearing simulator were tested using an air-bearing simulator consisting of a target star simulation unit and a control satellite simulation unit. The test is complete. The suspended gravity balance unit is reset and the ground simulation system is removed. The test method is used to test a space manipulation full-physics test system, which includes a target satellite simulation unit, a control satellite simulation unit, and a space robotic arm. The space robotic arm is located on one side of the control satellite simulation unit and includes a frame, a suspension and balancing gravity unit, and a support unit. The support unit is located inside the frame and has a smooth platform in the middle. The lower ends of the target satellite simulation unit and the control satellite simulation unit are supported by corresponding air-bearing units, and the air-bearing units are movably mounted on the smooth platform. The suspension and balancing gravity unit is movably mounted on the upper side of the frame and has a movable frame on the lower side. The movable frame has a movable hanging mechanism on the lower side, and the hanging mechanism has a liftable steel cable connected to the space robotic arm.

2. The ground simulation test method for complex manipulation processes of multi-space robots according to claim 1, characterized in that, The construction of the global spatial coordinate system specifically involves: The observable point in the support unit is taken as the origin of the absolute coordinate system, the vertical direction is the y direction, the horizontal direction along the main motion direction is the x direction, and the secondary motion direction is the z direction.

3. The ground simulation test method for complex control processes of multi-space robots according to claim 1, characterized in that, The gravity balance test includes the following steps: In the y-degree of freedom direction, the tension of the wire rope is detected by a force sensor installed in the suspension mechanism. The difference between the set value and the wire rope tension is used to control the winding and unwinding of the wire rope through force feedback, so that the tension of the wire rope is within the set value.

4. The ground simulation test method for complex control processes of multi-space robots according to claim 1, characterized in that, When the suspended gravity balancing unit moves along the zx direction, the inclination angle of the wire rope of the suspended gravity balancing unit is controlled by the actuators set in the Z and X directions of the suspended gravity balancing unit, so that the wire rope always remains perpendicular to the ground.

5. The ground simulation test method for complex control processes of multi-space robots according to claim 1, characterized in that, The obstacle avoidance test in the zx direction is specifically as follows: The distance between the crossbeam and the moving frame in the suspended gravity balance unit is obtained in real time. When the distance between the crossbeams meets the collision condition of the moving frame, the logical protection boundary is obtained based on the minimum spacing between the moving frames. The crossbeam collision prediction result is obtained based on the logical protection boundary.

6. The ground simulation test method for complex manipulation processes of multi-space robots according to claim 1, characterized in that, The steering angle, steering speed, and drive speed of the steering wheel in the test air-bearing simulator are specifically as follows: The air-floating simulator performs operations such as raising the steering wheel, rotating the steering wheel, lowering the steering wheel, and raising the braking mechanism to capture the target. The simulator's motion trajectory is planned in real time and calculated into the motion trajectory of the steering wheel. The steering angle, steering speed, and driving speed of the two steering wheels are calculated in real time. The steering wheel is driven by a motor to rotate and move, so that the simulator can perform the actions according to the motion trajectory.

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