Gravity balance test system combining air floatation and active follow-up suspension

Abstract

The application discloses a gravity balance test system combining air floating and active follow-up hanging, and belongs to the field of space robot simulation test technology.The gravity balance test system comprises an air floating table, a portal frame, a follow-up gravity unloading hanging point, an absolute positioning measurement system and a space robot satellite simulator, wherein the follow-up gravity unloading hanging point is arranged on the portal frame, the space robot satellite simulator is suspended on the air floating table, a mechanical arm of the space robot satellite simulator is connected with the follow-up gravity unloading hanging point, a laser radar sensor of the absolute positioning measurement system is arranged on the top of the space robot satellite simulator, and a multi-point laser reflection target array of the absolute positioning measurement system is arranged on the portal frame; and the absolute positioning measurement system measures the absolute position and attitude of the space robot satellite simulator relative to the portal frame in real time.The application can effectively carry out six-degree-of-freedom control test in a three-dimensional space under a ground gravity environment for space large antenna assembly, satellite maintenance and rescue, space remote operation and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of satellite ground test, and particularly relates to a gravity balance test system combining air floatation and active follow-up hanging. BACKGROUND

[0002] With the development of space technology, future satellites will have the ability to be repaired and maintained on orbit. At the same time, various service-type space robot satellites will emerge as the times require to carry out on-orbit control services on the fault satellites already on orbit.

[0003] Therefore, ground tests are needed to solve satellite approaching capture, repair operation, propellant supplement and the like. With the increasing mass and inertia of satellites and the increasing complexity of on-orbit tasks, larger satellite simulators and more degrees of freedom of gravity unloading are needed for corresponding ground test verification. For service-type space robot satellites equipped with multiple mechanical arms, in addition to the unloading of the satellite body, real-time gravity unloading of the mechanical arms in space motion is needed to carry out space control tests in the ground gravity environment. The traditional air floatation table can only realize in-plane motion and cannot provide more degrees of freedom of gravity unloading simulation in addition to the unloading of the satellite body. The active follow-up hanging is mainly used for local gravity unloading of small-range motion of the antenna and the joints of the mechanical arm in the past. Due to the influence of the design scheme and the motion control accuracy, a large-scale active follow-up hanging gravity balance design application has not been seen at present. Therefore, the three-dimensional six-degree-of-freedom control test of space large antenna assembly, satellite repair rescue, space remote operation and the like in the ground gravity environment lacks effective verification means. SUMMARY

[0004] The application solves the technical problem of overcoming the deficiencies of the prior art and providing a gravity balance test system combining air floatation and active follow-up hanging, which can effectively carry out the three-dimensional six-degree-of-freedom control test of space large antenna assembly, satellite repair rescue, space remote operation and the like in the ground gravity environment.

[0005] The application is achieved by the technical solutions below: a gravity balance test system combining air floatation and active follow-up hanging, comprising: an air floatation table, a gantry, a follow-up gravity unloading hanging point, an absolute positioning measurement system and a space robot satellite simulator; wherein, the follow-up gravity unloading hanging point is arranged on the gantry; the space robot satellite simulator is suspended on the air floatation table; a mechanical arm of the space robot satellite simulator is connected with the follow-up gravity unloading hanging point; a laser radar sensor of the absolute positioning measurement system is arranged on the top of the space robot satellite simulator, and a multi-point laser reflection target array of the absolute positioning measurement system is arranged on the gantry; the absolute positioning measurement system measures the absolute position and attitude of the space robot satellite simulator relative to the gantry in real time.

[0006] In the gravity balance test system combining air floatation and active follow-up hanging, the gantry comprises six support columns, a circumferential cross beam, lateral diagonal braces, a maintenance platform and two beam parallel rails; wherein, the six support columns are arranged on both sides of the air floatation table; the circumferential cross beam is connected with the top of the support columns; adjacent two support columns on the same side of the air floatation table are connected through lateral diagonal braces.

[0007] The two beam parallel rails are arranged on the upper part of the circumferential cross beam and are opposite to each other; the follow-up gravity unloading hanging point is connected with the beam parallel rails, and the follow-up gravity unloading hanging point can move along the length direction of the beam parallel rails; the maintenance platform is arranged on the side of the circumferential cross beam.

[0008] In the gravity balance test system combining air floatation and active follow-up hanging, the follow-up gravity unloading hanging point comprises a beam driving motor, a beam driving controller, a beam truss, a hanging point rail, a hanging point driving controller and a gravity balance servo mechanism; wherein, one end of the beam truss is connected with one beam parallel rail, and the other end of the beam truss is connected with the other beam parallel rail; the beam driving motor and the beam driving controller are arranged on one end of the beam truss, the beam driving motor and the beam driving controller are connected, the beam driving controller controls the beam driving motor to drive the beam truss to move along the length direction of the beam parallel rail; the hanging point rail is arranged on the upper part of the beam truss, the gravity balance servo mechanism is connected with the hanging point rail, the hanging point driving controller is connected with the gravity balance servo mechanism, and the hanging point driving controller controls the gravity balance servo mechanism to move along the length direction of the hanging point rail; wherein, the length direction of the hanging point rail is parallel to the length direction of the beam truss.

[0009] In the gravity balance test system combining air floating and active follow-up hanging, the hoisting point driving controller decomposes the angle value of the two-axis swing angle measurement sensor of the steel wire rope of the hoisting point of the mechanical arm into linear motion in two directions in a plane, controls the gravity balance servo mechanism to move in two perpendicular linear directions along the length direction of the hoisting point guide rail and along the length direction of the girder truss, so as to ensure that the steel wire rope of the hoisting point of the mechanical arm is always vertical to the air floating table; the hoisting point driving controller also controls the gravity balance servo mechanism to realize steel wire rope tension keeping according to the steel wire rope tension value measured by the tension sensor, so as to realize follow-up gravity unloading with the mechanical arm required to balance gravity.

[0010] In the gravity balance test system combining air floating and active follow-up hanging, the absolute positioning measurement system comprises a laser radar sensor and a multi-point laser reflection target array; wherein the laser radar sensor is arranged on the top of the space robot satellite simulator, and the multi-point laser reflection target array is arranged on the gantry.

[0011] In the gravity balance test system combining air floating and active follow-up hanging, the laser radar sensor rotates at a set angular velocity, continuously scans the multi-point laser reflection target array on the gantry, and obtains a measurement matrix described by polar coordinates of the space robot satellite simulator relative to the multi-point laser reflection target array; the polar coordinates of the space robot satellite simulator relative to the multi-point laser reflection target array are converted into a rectangular coordinate array described under the air floating table layout coordinate system, and the optimal estimated coordinates of the space robot satellite simulator under the air floating table layout coordinate system are obtained through least square fitting of the rectangular coordinates.

[0012] In the gravity balance test system combining air floating and active follow-up hanging, the measurement matrix described by polar coordinates of the space robot satellite simulator relative to the multi-point laser reflection target array is obtained through the following formula:

[0013]

[0014] Wherein, S is a distance array from the laser radar sensor to the laser reflection target array; A is an angle value with the initial angle of laser radar scanning as a starting point and laser scanning rate and frequency as increments; s i is the distance from the laser radar sensor installed under the body coordinate system of the space robot satellite simulator to the laser reflection target No. i; θ i is the rotation angle of the laser radar sensor scanning device when receiving the signal emitted by the laser reflection target No. i, i=0, 1, 2, …, n.

[0015] In the gravity balance test system combining air floating and active follow-up hanging, the rectangular coordinate array described under the air floating table layout coordinate system is obtained through the following formula:

[0016]

[0017] wherein, x i is the x-axis direction rectangular coordinate of the space robot satellite simulator body coordinate system origin described under the air floating table layout coordinate system, y i is the y-axis direction rectangular coordinate of the space robot satellite simulator body coordinate system origin described under the air floating table layout coordinate system, s i is the distance from the laser radar sensor installed under the space robot satellite simulator body coordinate system to the No. i laser reflection target, θ i is the rotation angle when the No. i laser reflection target emits a signal received by the laser radar sensor scanning device, i = 0, 1, 2, … n.

[0018] In the gravity balance test system combining air floating and active follow-up hanging, the space robot satellite simulator comprises a simulator body, an air floating chassis, a mechanical arm and a monitoring system; wherein the air floating chassis is arranged at the bottom of the simulator body; the mechanical arm is connected with the simulator body; the shoulder part, the elbow part and the wrist part of the mechanical arm are all provided with a hanging point protection tool corresponding to the follow-up gravity unloading hanging point, the follow-up gravity unloading hanging point is connected with the hanging point protection tool through a steel wire rope, and the hanging point protection tool realizes rolling, pitching and yawing movements according to the movement degrees of freedom of the mechanical arm; the monitoring system is arranged at the boundary position on the top of the simulator body, and the monitoring system can shoot images of the test process.

[0019] In the gravity balance test system combining air floating and active follow-up hanging, the space robot satellite simulator further comprises a main control system; wherein the main control system is connected with the follow-up gravity unloading hanging point, the absolute positioning measurement system and the space robot satellite simulator respectively; the main control system collects the angle value of the two-axis swing angle measurement sensor of the steel wire rope of the follow-up gravity unloading hanging point and the tension value of the steel wire rope measured by the tension sensor as the input of the control system, decomposes and plans the movement distance of the follow-up gravity unloading hanging point along the length direction of the beam parallel guide rail, so as to ensure that the steel wire rope always keeps vertical with the air floating table; the main control system receives the absolute position and attitude of the space robot satellite simulator relative to the gantry, plans the movement trajectory and movement speed of the space robot satellite simulator under the air floating table layout coordinate system, and sends the driving instruction to the air floating chassis of the space robot satellite simulator; the main control system receives the images of the test process shot by the monitoring system, and can also remotely adjust the focus, exposure time and camera holder movement of the monitoring camera of the monitoring system to realize follow shooting and angle adjustment.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] (1) The present application combines the air floating mode of the satellite simulator to overcome the ground gravity test with the follow-up hanging mode of the mechanical arm to overcome the ground gravity to achieve the ability of the space robot satellite with the mechanical arm to carry out the in-orbit assembly, in-orbit module replacement, in-orbit maintenance and other control tests on the ground under the ground gravity environment;

[0022] (2) The present application arranges the laser radar sensor on the satellite simulator, installs the laser reflection target array on the gantry fixed on the air floating table after calibration, and builds the absolute positioning measurement system of the satellite simulator in the test area. The absolute positioning measurement system can realize the measurement of the position, attitude, speed and angular velocity of the satellite simulator in the air floating table plane. When applied to multiple satellite simulators running on the air floating table, the relative position and attitude, relative speed measurement and control can be realized. The in-orbit two-satellite rendezvous docking, approaching parking and formation flight test can be simulated with high relative control accuracy on the ground;

[0023] (3) The present application unloads the mechanical arm by arranging the follow-up gravity unloading hanging point which can realize real-time closed-loop force control and large-range closed-loop motion control on the air floating table, so as to achieve the 6-DOF gravity balance in a three-dimensional space of dozens of meters, which overcomes the deficiency that the air floating test cannot realize 6-DOF gravity balance. BRIEF DESCRIPTION OF DRAWINGS

[0024] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the application. Moreover, the same reference numerals are used throughout the same figures. In the drawings:

[0025] Figure 1 is a gravity balance test system composition diagram provided by the air floating and active follow-up hanging combination of the embodiment of the present application;

[0026] Fig. 2(a) is a perspective view of the air floating table provided by the embodiment of the present application;

[0027] Fig. 2(b) is a bottom view of the air floating table provided by the embodiment of the present application;

[0028] Figure 3 is a three-view diagram of the gantry provided by the embodiment of the present application;

[0029] Figure 4 is a schematic diagram of the follow-up gravity unloading hanging point provided by the embodiment of the present application;

[0030] Figure 5 is a schematic diagram of the hanging point driving controller and the gravity balance hanging point provided by the embodiment of the present application;

[0031] Figure 6 is a schematic diagram of a space robot satellite simulator provided by an embodiment of the present application. DETAILED DESCRIPTION

[0032] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood, and the scope of the present disclosure can be accurately conveyed to those skilled in the art. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0033] Figure 1 is a composition diagram of a gravity balance test system combining air flotation and active follow-up suspension provided by an embodiment of the present application. As shown in Figure 1 the gravity balance test system combining air flotation and active follow-up suspension includes an air flotation table 1, a gantry 2, a follow-up gravity unloading suspension point 3, an absolute positioning measurement system 4, and a space robot satellite simulator 5. The follow-up gravity unloading suspension point 3 is arranged on the gantry 2. The space robot satellite simulator 5 is suspended on the air flotation table 1. The mechanical arm of the space robot satellite simulator 5 is connected with the follow-up gravity unloading suspension point 3. The laser radar sensor 401 of the absolute positioning measurement system 4 is arranged on the top of the space robot satellite simulator 5, and the multi-point laser reflection target array 402 of the absolute positioning measurement system 4 is arranged on the gantry 2. The absolute positioning measurement system 4 measures the absolute position and attitude of the space robot satellite simulator 5 relative to the gantry 2 in real time.

[0034] Through the combination of the air flotation of the space robot satellite simulator 5 and the follow-up gravity unloading of the mechanical arm on the satellite, and the cooperation of the absolute position and attitude measurement in the test area, the full-size several-ton satellite simulator can complete controllable three-dimensional space motion in the ground gravity environment.

[0035] As shown in FIGS. 2(a) and 2(b), the air flotation table 1 is spliced by high-strength and high-flatness granite slabs, and is arranged on the anti-settlement and anti-vibration cement foundation through adjustable supports. In order to improve the installation flatness and splicing accuracy of the air flotation table 1, the support of the air flotation table 1 is fine-adjusted by measuring the plane data through a laser level, and the height of the support of the air flotation table 1 is adjusted by raising / lowering through a wheeled adjustment mechanism. The chassis of the space robot satellite simulator 5 is suspended on the air flotation table 1 by filling the air flotation pad with high-pressure air. The mechanical arm of the space robot satellite simulator 5 overcomes gravity through the three follow-up gravity unloading suspension points 3 of the wrist, elbow, and shoulder.

[0036] As shown in Figure 3As shown, the gantry 2 includes 6 support columns 201, a circumferential cross beam 202, lateral diagonal braces 203, an inspection platform 204, and two girder parallel rails 205; wherein the 6 support columns 201 are arranged on both sides of the air floating platform 1; the circumferential cross beam 202 is connected to the top of the support columns 201; the adjacent two support columns 201 on the same side of the air floating platform 1 are connected through the lateral diagonal braces 203; the two girder parallel rails 205 are arranged on the upper part of the circumferential cross beam 202, and the two girder parallel rails 205 are opposite to each other; the follow-up gravity unloading lifting point 3 is connected to the girder parallel rails 205, and the follow-up gravity unloading lifting point 3 can move along the length direction of the girder parallel rails 205; the inspection platform 204 is arranged on the side of the circumferential cross beam 202.

[0037] The gantry 2 is used as the installation base of the follow-up gravity unloading lifting point 3 and the absolute positioning measurement system 4, adopts a large-span cage-shaped steel truss structure, and covers the air floating platform 1 directly above. The gantry 2 is composed of 6 support columns 201, a circumferential cross beam 202, lateral diagonal braces 203, an inspection platform 204, and girder parallel rails 205. Among them, the support columns 201 are arranged on both sides of the air floating platform 1 and are fixed through foundation screws. The support columns 201 are the main bearing structures of the entire gantry 2, and the circumferential cross beam 202 is arranged on the support columns 201. The circumferential cross beam 202 and the support columns 201 are improved in structural rigidity through the lateral diagonal braces 203. At the same time, the support columns 201, the circumferential cross beam 202, and the lateral diagonal braces 203 are arranged with a calibrated multi-point laser reflection target array 402 of the absolute positioning measurement system 4, so as to provide an absolute position reference for the space robot satellite simulator 5 moving on the air floating platform 1.

[0038] Above the circumferential cross beam 202, the girder parallel rails 205 of the follow-up gravity unloading lifting point 3 in motion are arranged. The girder parallel rails 205 include a sliding rail, a rack, a grating ruler, a cable routing groove, and a drag chain, etc. The girder driving motor 301 of the follow-up gravity unloading lifting point 3 drives the meshing gear to realize the motion of the follow-up gravity unloading lifting point 3 relative to the sliding rail and the rack of the girder parallel rails 205. The grating ruler of the girder parallel rails 205 gives an accurate motion stroke, and the cable routing groove and the drag chain provide a power supply cable for the follow-up.

[0039] Near the outside of the circumferential cross beam 202, the inspection platform 204 of the follow-up gravity unloading lifting point 3 is installed. It is convenient to maintain and repair the laser reflection target 402 of the absolute positioning measurement system 4 and the follow-up gravity unloading lifting point 3.

[0040] As shown in FIG. 1, the air floating platform 1 is arranged on the ground 100, and the follow-up gravity unloading lifting point 3 is arranged on the air floating platform 1. The follow-up gravity unloading lifting point 3 is connected to the absolute positioning measurement system 4, and the absolute positioning measurement system 4 is connected to the space robot satellite simulator 5. Figure 4 and Figure 5As shown, the follow-up gravity unloading lifting point 3 comprises a beam driving motor 301, a beam driving controller 302, a beam truss 303, a lifting point guide rail 304, a lifting point driving controller 305 and a gravity balance servo mechanism 306; one end of the beam truss 303 is connected with one beam parallel guide rail 205, and the other end of the beam truss 303 is connected with another beam parallel guide rail 205; the beam driving motor 301 and the beam driving controller 302 are arranged at one end of the beam truss 303, the beam driving motor 301 is connected with the beam driving controller 302, and the beam driving controller 302 controls the beam driving motor 301 to drive the beam truss 303 to move along the length direction of the beam parallel guide rail 205;

[0041] The lifting point guide rail 304 is arranged at the upper part of the beam truss 303, the gravity balance servo mechanism 306 is connected with the lifting point guide rail 304, the lifting point driving controller 305 is connected with the gravity balance servo mechanism 306, and the lifting point driving controller 305 controls the gravity balance servo mechanism 306 to move along the length direction of the lifting point guide rail 304; the length direction of the lifting point guide rail 304 is parallel to the length direction of the beam truss 303.

[0042] The follow-up gravity unloading lifting point 3 is installed on the gantry 2 and has two vertical guide rails parallel to the plane of the air floating table 1. The movement range of the follow-up gravity unloading lifting point 3 covers the entire air floating table 1. The end of the follow-up gravity unloading lifting point 3 is connected to the lifting point protection tool of the mechanical arm 503 through a steel wire rope, and the lifting point protection tool can realize rolling, pitching and yawing movable hinges according to the movement degrees of freedom of the mechanical arm 503, so as to adapt to the spatial movement of the mechanical arm 503. Multiple sets of follow-up gravity unloading lifting points 3 can be arranged on the gantry 2 according to the task requirements, so as to realize multi-point unloading.

[0043] The follow-up gravity unloading lifting point 3 is composed of the beam driving motor 301, the beam driving controller 302, the beam truss 303, the lifting point guide rail 304, the lifting point driving controller 305 and the gravity balance servo mechanism 306.

[0044] The beam driving motor 301 and the beam driving controller 302 are installed at one end of the beam truss 303. Under the control of the beam driving controller 302, the beam driving motor 301 drives the end gear to rotate, and the gear meshes with the rack arranged on the beam parallel guide rail 205 to move. The position information of the grating ruler on the beam parallel guide rail 205 is collected to form a closed-loop motion control.

[0045] The lifting point guide rail 304 of the follow-up gravity unloading lifting point 3, the lifting point drive controller 305 and the gravity balance servo mechanism 306 each correspond to one, and form an independent gravity unloading lifting point. The lifting point guide rail 304 is connected with the girder truss 303 through a sliding rail and can move linearly on the girder truss 303. The gravity balance servo mechanism 306 can move along the lifting point guide rail 304 under the control of the lifting point drive controller 305. The lifting point drive controller 305 is fixed on the support structure of the lifting point guide rail 304 and has no relative movement.

[0046] The lifting point drive controller 305 decomposes the angle value of the two-axis swing angle measurement sensor of the steel wire rope of the mechanical arm lifting point into linear motion in two directions in the plane, controls the gravity balance servo mechanism 306 to move along the two mutually perpendicular linear directions of the lifting point guide rail 304 and the girder truss 303, and thus ensures that the steel wire rope of the lifting point is always vertical to the air floating table 1. At the same time, the lifting point drive controller 305 also controls the gravity balance servo mechanism 306 to realize the steel wire rope tension keeping according to the steel wire rope tension value measured by the tension sensor, and realizes the follow-up gravity unloading with the mechanical arm 503 required to balance the gravity.

[0047] As shown in Figure 3 and Figure 6 , the absolute positioning measurement system 4 includes a laser radar sensor 401 and a multi-point laser reflection target array 402; wherein the laser radar sensor 401 is arranged on the top of the space robot satellite simulator 5, and the multi-point laser reflection target array 402 is arranged on the gantry 2.

[0048] The absolute positioning measurement system 4 is composed of the laser radar sensor 401 installed on the top of the space robot satellite simulator 5 and the calibrated multi-point laser reflection target array 402 installed on the frame / pillar of the gantry 2. The absolute position and attitude of the space robot satellite simulator 5 relative to the gantry 2 are measured in real time. Since the position of the gantry 2 relative to the air floating table 1 can be calibrated, the arrangement of various types of absolute positioning measurement system 4 combinations (such as laser range finder, binocular visible light measurement, etc.) on the space robot satellite simulator 5 can realize the three-dimensional space absolute position and attitude measurement of the space robot satellite simulator 5 in the test site. When applied to multiple space robot satellite simulators 5 at the same time, the relative position and attitude between multiple satellite simulators can be obtained accordingly.

[0049] The working principle of the absolute positioning measurement system 4 is as follows:

[0050] 1) The laser radar sensor 401 installed on the top of the space robot satellite simulator 5 scans the surrounding environment through 360° omnidirectional scanning, and obtains the sequence distance information relative to the laser reflection target array 402.

[0051] 2) Establish a reference coordinate system with the LIDAR sensor 401 on the space robot satellite simulator 5;

[0052] 3) The LIDAR sensor 401 rotates at a set angular velocity, continuously scans the laser reflection target array 402 on the gantry 2, and obtains a measurement matrix described in polar coordinates:

[0053]

[0054] In the formula: S is the distance array of the LIDAR sensor to the laser reflection target; A is the angle value with the initial angle of the LIDAR scan as the starting point and the laser scan rate and frequency as the increments. i is the distance of the LIDAR sensor installed in the space robot satellite simulator body coordinate system to the i-th laser reflection target; θ i is the rotation angle of the LIDAR sensor scanning device when receiving the signal emitted by the i-th laser reflection target, i = 0, 1, 2, …, n.

[0055] 4) Since each laser reflection target 402 is fixed on the gantry, the gantry is fixed relative to the air floating table and has been calibrated, so the polar coordinates of the space robot satellite simulator 5 relative to the laser reflection target can be converted into rectangular coordinates described in the air floating table 1 layout coordinate system:

[0056]

[0057] In the formula, x i is the distance s i and the rotation angle θ i determined according to the i-th laser reflection target, and y i is the rectangular coordinate of the x-axis direction described in the air floating table layout coordinate system with the origin of the space robot satellite simulator body coordinate system, s i is the distance s i and the rotation angle θ i determined according to the i-th laser reflection target, and y i is the rectangular coordinate of the y-axis direction described in the air floating table layout coordinate system with the origin of the space robot satellite simulator body coordinate system.

[0058] 5) The LIDAR sensor 401 scans n laser reflection targets to obtain n rectangular coordinates. Through least squares fitting of the rectangular coordinates, the optimal estimated coordinates of the space robot satellite simulator 5 in the air floating table 1 layout coordinate system are obtained.

[0059] AsFigure 6 As shown, the space robot satellite simulator 5 comprises a simulator body 501, an air floating chassis 502, a mechanical arm 503 and a monitoring system 504; wherein the air floating chassis 502 is arranged at the bottom of the simulator body 501; the mechanical arm 503 is connected with the simulator body 501; the shoulder part, the elbow part and the wrist part of the mechanical arm 503 are all provided with a lifting point protection tool corresponding to the follow-up gravity unloading lifting point 3, the follow-up gravity unloading lifting point 3 is connected with the lifting point protection tool through a steel wire rope, and the lifting point protection tool realizes rolling, pitching and yawing movements according to the movement degrees of freedom of the mechanical arm 503; the monitoring system 504 is arranged at the boundary position on the top of the simulator body 501, and the monitoring system 504 can shoot images of the test process.

[0060] The simulator body 501 provides installation interfaces of the air floating chassis 502, the mechanical arm 503, the monitoring system 504 and the laser radar sensor 401, including mechanical interfaces, power supply and control information chain. The simulator body 501 provides wireless communication with the main control system 6.

[0061] The air floating chassis 502 supports the simulator body 501, and comprises frame structures, air floating pad groups, rudder wheels, suction disc brakes, lead-acid battery groups and other components. The space robot satellite simulator 5 realizes planar movement on the air floating platform 1.

[0062] The mechanical arm 503 is installed in the forward direction of the simulator body 501, and the lifting point protection tool of the follow-up gravity unloading lifting point 3 is fixed on the shoulder part, the elbow part and the wrist part of the mechanical arm 503 respectively, and the lifting point protection tool can realize rolling, pitching and yawing movable hinges according to the movement degrees of freedom of the mechanical arm 503, and adapt to the space movement of the mechanical arm 503. The power supply and driving control of the mechanical arm 503 are realized by the driving computer on the simulator body 501.

[0063] The monitoring system 504 is installed on the periphery of the simulator body 501, shoots images of the test process, and transmits the images to the main control system 6 in real time through the wireless communication computer of the simulator body 501.

[0064] The gravity balance test system combining air floating and active follow-up hanging further comprises a main control system 6; wherein the main control system 6 collects and processes data such as tension, swing angle, position, angle, speed, angular velocity and driving current of the follow-up gravity unloading lifting point 3, the absolute positioning measurement system 4 and the space robot satellite simulator 5, plans and controls the movement trajectory of the space robot satellite simulator 5 on the air floating platform 1 and the space movement of the follow-up gravity unloading lifting point 3 through a multi-channel wireless local area network.

[0065] Specifically, the main control system 6 collects the angle value of the two-axis swing angle measurement sensor of the follow-up gravity unloading lifting point 3 of the steel wire rope and the tension value of the tension sensor of the steel wire rope as the input of the control system, decomposes and plans the movement distance of the follow-up gravity unloading lifting point 3 of the satellite along the length direction of the parallel guide rail 205 of the beam, so as to ensure that the steel wire rope is always kept vertical with the air floating table 1; the main control system 6 receives the absolute position and attitude of the space robot satellite simulator 5 relative to the gantry 2, plans the movement trajectory and movement speed of the space robot satellite simulator 5 in the layout coordinate system of the air floating table 1, and sends a driving instruction to the air floating chassis 502 of the space robot satellite simulator 5; the main control system 6 receives the image of the test process shot by the monitoring system 504, and can also remotely adjust the focus, exposure time and camera holder movement of the monitoring camera of the monitoring system 504 to realize follow-up shooting and angle adjustment.

[0066] The embodiment combines the characteristics of the air floating of the satellite body and the follow-up hanging of the mechanical arm, the air floating pad is installed at the lower end face of the satellite body, the movement in the air floating table plane can be realized. The mechanical arm is unloaded by the active follow-up hanging, and the follow-up tracking is performed by monitoring the swing angle of the hanging wire and the tension size in the gravity direction. Thus, the problem that the space satellite with the mechanical arm cannot carry out in-orbit assembly, in-orbit module replacement, in-orbit maintenance and other tests under the ground gravity environment is solved, and the embodiment can provide ground test conditions for the development of subsequent space control technology.

[0067] The embodiment combines the air floating mode of the satellite simulator overcoming the ground gravity test and the follow-up hanging mode of the mechanical arm overcoming the ground gravity to carry out control test. The ability of the space robot satellite with the mechanical arm to carry out in-orbit assembly, in-orbit module replacement, in-orbit maintenance and other control tests on the ground under the ground gravity environment is achieved. The laser radar sensor is arranged on the satellite simulator, the laser reflection target array is installed on the gantry fixed relative to the air floating table after calibration, and the absolute positioning measurement system of the satellite simulator in the test area is built. The position, attitude, speed and angular velocity of the satellite simulator in the air floating table plane can be measured by using the absolute positioning measurement system. When applied to multiple satellite simulators running on the air floating table, the relative position and attitude, relative speed measurement and control can be realized. The in-orbit two-satellite rendezvous docking, approaching parking and formation flight test under the ground environment can be simulated with high relative control precision. The mechanical arm is unloaded by the follow-up gravity unloading lifting point arranged on the air floating table which can realize real-time closed-loop force control and wide-range closed-loop motion control, so that the 6-degree-of-freedom gravity balance in a three-dimensional space of dozens of meters can be achieved, and the deficiency that the 6-degree-of-freedom gravity balance cannot be realized in the air floating test is overcome.

[0068] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application shall fall within the protection scope of the technical solutions of the present application.

Claims

1. A gravity balance test system combining air floatation and active servo-hanging, characterized in that The air floating platform (1), the gantry (2), the follow-up gravity unloading lifting point (3), the absolute positioning measurement system (4) and the space robot satellite simulator (5); wherein, The follow-up gravity unloading lifting point (3) is arranged on the gantry (2); The space robot satellite simulator (5) is suspended on the air floating platform (1); The mechanical arm of the space robot satellite simulator (5) is connected with the follow-up gravity unloading lifting point (3); The laser radar sensor (401) of the absolute positioning measurement system (4) is arranged on the top of the space robot satellite simulator (5), and the multi-point laser reflection target array (402) of the absolute positioning measurement system (4) is arranged on the gantry (2); the absolute positioning measurement system (4) measures the absolute position and attitude of the space robot satellite simulator (5) relative to the gantry (2) in real time; The gantry (2) comprises six support columns (201), a circumferential cross beam (202), a lateral diagonal brace (203), a maintenance platform (204) and two girder parallel guide rails (205); wherein, The six support columns (201) are arranged on both sides of the air floating platform (1); The circumferential cross beam (202) is connected with the top of the support column (201); The adjacent two support columns (201) located on the same side of the air floating platform (1) are connected through the lateral diagonal brace (203); The two girder parallel guide rails (205) are arranged on the upper part of the circumferential cross beam (202), and the two girder parallel guide rails (205) are opposite to each other; The follow-up gravity unloading lifting point (3) is connected with the girder parallel guide rail (205), and the follow-up gravity unloading lifting point (3) can move along the length direction of the girder parallel guide rail (205); The maintenance platform (204) is arranged on the side of the circumferential cross beam (202); The follow-up gravity unloading lifting point (3) comprises a girder driving motor (301), a girder driving controller (302), a girder truss (303), a lifting point guide rail (304), a lifting point driving controller (305) and a gravity balance servo mechanism (306); wherein, One end of the girder truss (303) is connected with one girder parallel guide rail (205), and the other end of the girder truss (303) is connected with the other girder parallel guide rail (205); The girder driving motor (301) and the girder driving controller (302) are arranged at one end of the girder truss (303), the girder driving motor (301) and the girder driving controller (302) are connected, and the girder driving controller (302) controls the girder driving motor (301) to drive the girder truss (303) to move along the length direction of the girder parallel guide rail (205). ​ The hanging point guide rail (304) is arranged on the upper part of the girder truss (303), the gravity balance servo mechanism (306) is connected with the hanging point guide rail (304), the hanging point driving controller (305) is connected with the gravity balance servo mechanism (306), and the hanging point driving controller (305) controls the gravity balance servo mechanism (306) to move along the length direction of the hanging point guide rail (304); wherein the length direction of the hanging point guide rail (304) is parallel to the length direction of the girder truss (303); The hanging point driving controller (305) decomposes the angle value of the two-axis swing angle measurement sensor of the steel wire rope of the mechanical arm hanging point into the linear motion in two directions in the plane, controls the gravity balance servo mechanism (306) to move in two linear directions perpendicular to each other along the length direction of the hanging point guide rail (304) and the length direction of the girder truss (303), so as to ensure that the steel wire rope of the mechanical arm hanging point is always kept vertical with the air floating table (1); The hanging point driving controller (305) also controls the gravity balance servo mechanism (306) to realize the steel wire rope tension keeping according to the steel wire rope tension value measured by the tension sensor, so as to realize the follow-up gravity unloading with the mechanical arm required to balance the gravity; The absolute positioning measurement system (4) comprises a laser radar sensor (401) and a multi-point laser reflection target array (402); wherein, The laser radar sensor (401) is arranged on the top of the space robot satellite simulator (5), and the multi-point laser reflection target array (402) is arranged on the gantry (2); The laser radar sensor (401) rotates at a set angular velocity, continuously scans the multi-point laser reflection target array (402) on the gantry (2), and obtains a measurement matrix described in polar coordinates of the space robot satellite simulator (5) relative to the multi-point laser reflection target array (402); The polar coordinates of the space robot satellite simulator (5) relative to the multi-point laser reflection target array (402) are converted into a rectangular coordinate array described in the air floating table (1) layout coordinate system, and the optimal estimation coordinates of the space robot satellite simulator (5) in the air floating table (1) layout coordinate system are obtained through least square fitting of the rectangular coordinates; The measurement matrix described in polar coordinates of the space robot satellite simulator (5) relative to the multi-point laser reflection target array (402) is obtained through the following formula: Wherein, S is the distance array of the laser radar sensor to the laser reflection target array; A is the angle value with the initial angle of the laser radar scanning as the starting point, the laser scanning rate and frequency as the increment; s i is the distance from the laser radar sensor installed in the space robot satellite simulator body coordinate system to the i-th laser reflection target; θ i is the rotation angle when the i-th laser reflection target emits a signal and is received by the laser radar sensor scanning device, i=0, 1, 2, …, n. The rectangular coordinate array described in the air floating table (1) layout coordinate system is obtained through the following formula: wherein, x i is the x-axis direction rectangular coordinate described by the origin of the space robot satellite simulator body coordinate system in the air floating table layout coordinate system, y i is the y-axis direction rectangular coordinate described by the origin of the space robot satellite simulator body coordinate system in the air floating table layout coordinate system, s i is the distance from the laser radar sensor installed in the space robot satellite simulator body coordinate system to the laser reflection target numbered i, θ i is the rotation angle when the laser radar sensor scanning device receives the signal emitted by the laser reflection target numbered i, i=0, 1, 2, …, n. The space robot satellite simulator (5) comprises a simulator body (501), an air floating chassis (502), a mechanical arm (503) and a monitoring system (504); wherein, The air floating chassis (502) is arranged on the bottom of the simulator body (501); The mechanical arm (503) is connected with the simulator body (501); the shoulder, elbow and wrist of the mechanical arm (503) are all provided with a lifting point protection tool corresponding to the follow-up gravity unloading lifting point (3); the follow-up gravity unloading lifting point (3) is connected with the lifting point protection tool through a steel wire rope; and the lifting point protection tool realizes rolling, pitching and yawing movements according to the movement freedom degree of the mechanical arm (503); The monitoring system (504) is arranged at a boundary position on the top of the simulator body (501); and the monitoring system (504) can shoot images of the test process; Further comprising: a main control system (6); wherein, The main control system (6) is connected with the follow-up gravity unloading lifting point (3), the absolute positioning measurement system (4) and the space robot satellite simulator (5) respectively; The main control system (6) collects the two-axis swing angle measurement sensor angle value of the follow-up gravity unloading lifting point (3) and the steel wire rope tension value measured by the tension sensor as the input of the control system, decomposes and plans the movement distance of the follow-up gravity unloading lifting point (3) along the length direction of the beam parallel guide rail (205), so as to ensure that the steel wire rope always keeps plumb with the air floating table (1); The main control system (6) receives the absolute position and attitude of the space robot satellite simulator (5) relative to the gantry (2), plans the movement trajectory and movement speed of the space robot satellite simulator (5) in the air floating table (1) layout coordinate system, and sends a driving instruction to the air floating chassis (502) of the space robot satellite simulator (5); The main control system (6) receives the images of the test process shot by the monitoring system (504), and can also remotely adjust the focus, exposure time and camera holder movement of the monitoring camera of the monitoring system (504) to realize follow shooting and angle adjustment.

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