Space assembly ground test system and method based on air floatation simulation

Abstract

The invention provides a space assembly ground test system and method based on air floatation simulation, and relates to the field of air floatation simulation, flight control and trajectory planning. The system comprises an air floatation simulation device, a marble platform, a first simulation wall, a second simulation wall, a third simulation wall, a mechanical arm, a ground measurement device and a ground comprehensive console, horizontally laying the marble platform; the first simulation wall, the second simulation wall and the third simulation wall are perpendicular to one another in pairs and are fixedly connected to the marble platform; the air floatation simulation device is arranged on the marble platform and located in a space defined by the first simulation wall, the second simulation wall and the third simulation wall; the ground integrated console is arranged on the side, close to the third simulation wall, of the marble platform. The problems of high cost and high risk caused by satellite orbit deviation and attitude out-of-control in the space assembly process are solved, a real space assembly test does not need to be carried out, and the cost and risk of the space assembly test are remarkably reduced.

Description

Technical Field

[0001] This invention relates to the fields of air-bearing simulation, flight control and trajectory planning, and in particular to a space assembly ground test system and method based on air-bearing simulation. Background Technology

[0002] Against the backdrop of the rapid development of space technology, on-orbit assembly and component replacement of satellites have become key means to improve satellite functionality and lifespan, and are an important direction for the development of space operation technology. However, this field is facing severe technical bottlenecks: during the space assembly process, satellites are prone to problems such as orbital deviation and attitude loss, which leads to excessively high costs for conducting real space assembly tests, and is accompanied by huge risks, seriously restricting the feasibility and reliability of complex space operation missions.

[0003] Therefore, there is an urgent need to develop a low-cost ground-based simulation space assembly test system and method to overcome the dual limitations of cost and risk in space assembly testing, and to provide a safer, more economical, and reliable ground verification solution for on-orbit space operations. Summary of the Invention

[0004] The purpose of this invention is to provide a space assembly ground test system and method based on air-bearing simulation, which solves the high cost and high risk problems caused by satellite orbit deviation and attitude loss during space assembly. It eliminates the need for actual space assembly tests, reduces the cost and risk of space assembly tests, and provides a safe, reliable and low-cost ground verification solution for satellite assembly, maintenance and replacement.

[0005] To achieve the above objectives, the present invention provides a space assembly ground test system based on air flotation simulation, comprising an air flotation simulation device, a marble platform, a first simulation wall, a second simulation wall, a third simulation wall, a robotic arm, a ground measuring device, and a ground integrated control console; the marble platform is laid horizontally; the first simulation wall, the second simulation wall, and the third simulation wall are perpendicular to each other and fixedly connected to the marble platform; the air flotation simulation device is set on the marble platform and located within the space defined by the first simulation wall, the second simulation wall, and the third simulation wall; the ground integrated control console is set on the side of the marble platform adjacent to the third simulation wall.

[0006] Preferably, the robotic arm is fixedly mounted on the first simulation wall.

[0007] Preferably, the ground measuring device is fixedly installed on the first simulation wall, the second simulation wall, and the third simulation wall.

[0008] Preferably, the ground-based integrated control console receives the position and orientation information of the air-float simulation device from the ground-based measuring device; based on the position and orientation information, the ground-based integrated control console runs a three-degree-of-freedom simulator control algorithm, generates control commands and sends them to the air-float simulation device, driving the air-float simulation device to adjust its position and orientation; after the air-float simulation device is adjusted to the predetermined position, the ground-based integrated control console controls the robotic arm to perform auxiliary fine-tuning operations on the air-float simulation device to complete the docking.

[0009] Preferably, the core of the three-degree-of-freedom simulator control algorithm is a three-degree-of-freedom simulator controller, which is an improved discrete PID controller. The improvement lies in setting the control period of the discrete PID controller to 100ms and using the 5th-order finite difference method to calculate the differential term of the discrete PID controller; the specific expression is as follows: ; ; ; ; ; ; in, Indicates the sampling time; Indicates an index variable; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction.

[0010] Preferably, the air flotation simulator is a three-degree-of-freedom simulator; the actuator of the air flotation simulator consists of eight cold jet propulsion units, which provide reaction thrust to control the position of the air flotation simulator and provide torque to control the attitude of the air flotation simulator.

[0011] Preferably, the eight cold jet thrusters are grouped into four groups of two, with each group consisting of two cold jet thrusters with opposite thrust directions. At the same time, an actuator thrust distribution strategy is adopted to treat the two cold jet thrusters in the same group as a resultant force unit for control quantity distribution, and to ensure that the two cold jet thrusters in the same group cannot work at the same time.

[0012] Preferably, the nozzle of the cold jet propulsion uses nitrogen as the working fluid, and the flow of the working fluid in the nozzle is theoretically designed based on the assumptions of steady, one-dimensional, isentropic flow; the nozzle of the cold jet propulsion adopts a supersonic nozzle design.

[0013] The present invention also provides a space assembly ground test method for the above-mentioned space assembly ground test system based on air-bearing simulation, comprising the following steps: Step S1: Obtain the position and attitude information of the air-float simulation device in real time through the ground measuring device; Step S2: The ground integrated control console receives the position and orientation information of the air-float simulation device. Based on the deviation between the position and orientation information of the air-float simulation device and the predetermined docking position, it runs the three-degree-of-freedom simulator control algorithm to calculate the control quantity required to control the movement of the air-float simulation device, and converts the control quantity into control commands and sends them to the air-float simulation device. Step S3: The air flotation simulation device drives the cold jet propulsion unit to work according to the control command, adjusts its own posture, and moves towards the predetermined docking position. Step S4: After the air flotation simulator moves to the predetermined docking position, the ground integrated control console controls the robotic arm to start and perform auxiliary fine-tuning operations on the air flotation simulator to finally complete the precision docking.

[0014] Therefore, the present invention employs the above-described space assembly ground test system and method based on air flotation simulation, and the beneficial technical effects are as follows: (1) This invention combines an air-floating simulation device with a marble platform to accurately simulate a three-degree-of-freedom microgravity motion environment in space. It adopts a three-degree-of-freedom simulator control algorithm with an improved discrete PID controller as the core, which significantly improves the calculation accuracy of the position deviation differential, effectively overcomes the accuracy challenge brought by the long control cycle in ground simulation, and realizes high stability control of the position and attitude of the air-floating simulation device.

[0015] (2) The present invention adopts an innovative actuator thrust distribution strategy to manage eight cold jet thrusters in groups and prohibits cold jet thrusters in opposite directions in the same group from working at the same time, which significantly reduces fuel consumption and avoids thrust loss.

[0016] (3) The present invention relies on the ground measuring device to monitor the position and posture information in real time, and the ground integrated control console centrally receives, processes and coordinates the operation of the air-floating simulation device and the robotic arm, realizing the fully automated operation from coarse positioning to fine docking.

[0017] (4) This invention does not require conducting real space assembly tests. It can fully verify the feasibility of space satellite parts assembly and replacement processes on the ground, fundamentally avoiding the risk of orbital deviation, greatly reducing test costs and technical risks, and providing a safe and reliable ground verification solution for space on-orbit operations. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a space assembly ground test system based on air flotation simulation; Figure 2 This is a flowchart illustrating a space assembly ground test method for a space assembly ground test system based on air-bearing simulation. Figure 3 This is a schematic diagram of the thrust of a cold jet propulsion system.

[0019] Figure Labels 1. Air flotation simulation device; 2. Marble platform; 3. First simulation wall; 4. Second simulation wall; 5. Third simulation wall; 6. Robotic arm; 7. Ground measuring device; 8. Ground integrated control console. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0022] Example 1 like Figure 1As shown, a space assembly ground test system based on air-float simulation includes an air-float simulation device 1, a marble platform 2, a first simulation wall 3, a second simulation wall 4, a third simulation wall 5, a robotic arm 6, a ground measuring device 7, and a ground integrated control console 8. The marble platform 2 is laid horizontally. The first simulation wall 3, the second simulation wall 4, and the third simulation wall 5 are perpendicular to each other and fixedly connected to the marble platform 2. The robotic arm 6 is fixedly installed on the first simulation wall 3. The ground measuring device 7 is fixedly installed on the first simulation wall 3, the second simulation wall 4, and the third simulation wall 5.

[0023] The air-bearing simulation device 1 is set on the marble platform 2 and located within the space defined by the first simulation wall 3, the second simulation wall 4, and the third simulation wall 5. The air-bearing simulation device 1 is a three-degree-of-freedom simulator; the actuator of the air-bearing simulation device 1 consists of eight cold jet thrusters, which are used to provide reaction thrust to control the position of the air-bearing simulation device 1 and to provide torque to control the attitude of the air-bearing simulation device 1.

[0024] The eight cold jet thrusters are divided into four groups of two, each group consisting of two cold jet thrusters with opposite thrust directions. At the same time, an actuator thrust distribution strategy is adopted to treat the two cold jet thrusters in the same group as a resultant force unit for control distribution, and to ensure that the two cold jet thrusters in the same group cannot work at the same time.

[0025] A schematic diagram of the thrust of a cold jet propulsion system is shown below. Figure 3 As shown. In this embodiment, cold jet thrusters 7 and 8, a group of thrusters with opposite thrust directions, are used as an example. The specific details of the actuator thrust distribution strategy are as follows: The thrust generated by cold jet thrusters 7 and 8 is in opposite directions. If cold jet thrusters 7 and 8 eject gas simultaneously, their thrust effects cancel each other out. From a fuel-saving perspective, cold jet thrusters 7 and 8 should not eject gas simultaneously. Treating cold jet thrusters 7 and 8 as a single resultant force unit, the specific expression is as follows: ; ; in, This represents the thrust vector of cold jet thrusters 7 and 8. This indicates the angle between the predetermined docking position and the current pose of the air flotation simulator 1; This indicates the maximum thrust that a cold jet propulsion system can provide. This indicates the thrust of cold jet thrusters 7 and 8.

[0026] when When the cold jet thruster 7 generates thrust, the cold jet thruster 8 shuts down; when When the value is 0, the cold jet thruster 8 generates thrust by jetting air, and the cold jet thruster 7 is turned off; when the value is 0, both the cold jet thruster 7 and the cold jet thruster 8 remain off.

[0027] The actuator thrust distribution strategy also applies to the three sets of cold jet thrusters: cold jet thrusters 9 and 10, cold jet thrusters 11 and 12, and cold jet thrusters 13 and 14, which will not be elaborated further.

[0028] To achieve position and attitude control of the satellite simulator, this embodiment is equipped with an actuator capable of generating control force and control torque, namely, a cold jet thruster to simulate the attitude and orbit control thruster of a real satellite. In the theoretical calculations of the cold jet thruster, for the nozzle of the cold jet thruster under actual conditions, to address the unsteady and multidimensional complexity of the fluid flow inside the nozzle, this embodiment idealizes the fluid flow inside the nozzle as a steady, one-dimensional, adiabatic, frictionless isentropic flow process, using nitrogen as a uniform ideal working gas. Furthermore, if the nozzle is to be designed for supersonic operation, the necessary condition of "the ratio of nozzle inlet pressure to nozzle outlet pressure exceeding a critical value" must be met, specifically expressed as: ; in, This represents the ratio of specific isobaric heat capacity to specific isocapacitance heat capacity; Indicates the nozzle inlet pressure; This indicates the nozzle exit pressure.

[0029] In this embodiment, the working fluid in the nozzle is nitrogen. Nitrogen's thermodynamic properties are similar to those of air, therefore... Calculations yielded .

[0030] The above calculation results show that when the nozzle inlet pressure is set to four atmospheres and the nozzle outlet pressure is one atmosphere in this embodiment, the necessary conditions for a supersonic nozzle are met. Therefore, the nozzle in this embodiment can be designed as a supersonic nozzle. The relevant expression is: ; ; in, This indicates the mass flow rate of the supersonic nozzle; This indicates the thrust of a supersonic nozzle; This represents the ratio of specific isobaric heat capacity to specific isocapacitance heat capacity. ; Indicates the nozzle inlet pressure; Indicates the nozzle outlet pressure; Indicates the cross-sectional area of ​​the throttling orifice; Represents the gas constant. ; Indicates the inlet temperature. .

[0031] Through the above theoretical design and formulas, this embodiment achieves accurate design and performance prediction of the cold jet propulsion system, thereby ensuring high-precision attitude control of the air-bearing simulation device.

[0032] The ground-based integrated control console 8 is located on one side of the marble platform adjacent to the third simulation wall 5. The ground-based integrated control console 8 receives the position and orientation information of the air-float simulation device 1 from the ground-based measuring device 7; based on the position and orientation information, the ground-based integrated control console 8 runs a three-degree-of-freedom simulator control algorithm, generates control commands and sends them to the air-float simulation device 1 to drive the air-float simulation device 1 to perform position and orientation adjustments; after the air-float simulation device 1 is adjusted to the predetermined position, the ground-based integrated control console 8 controls the robotic arm 6 to perform auxiliary fine-tuning operations.

[0033] The core of the three-degree-of-freedom simulator control algorithm is the three-degree-of-freedom simulator controller, which is an improved discrete PID controller.

[0034] In traditional discrete PID control, when the sampling period... When the value is extremely small, a conventional form of a discrete PID controller can be used, with the specific expression as follows: ; in, Indicates the first The controller calculates the output value at each sampling time. Indicates proportional gain; Indicates the first The systematic error at each sampling time; Indicates integral gain; Indicates the sampling time; Indicates from the first From 0 sampling time points to the 1st The sum of all systematic errors at each sampling time; Indicates an index variable; Represents differential gain; Indicates the first The systematic error at each sampling time.

[0035] However, the control cycle of the three-degree-of-freedom simulator controller in this embodiment is 100ms, which is relatively long. If the conventional differential term calculation method is used, the calculation accuracy will decrease. To solve this problem, this embodiment uses the fifth-order finite difference method to calculate the differential term of the discrete PID controller, thereby improving the calculation accuracy of the pose deviation differential.

[0036] The specific expression for the improved discrete PID controller is as follows: ; ; ; ; ; ; in, Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction.

[0037] like Figure 2 As shown, a space assembly ground test method for the aforementioned air-bearing simulation-based space assembly ground test system includes the following steps: Step S1: Obtain the position and orientation information of the air-float simulation device 1 in real time through the ground measuring device 7.

[0038] Step S2: The ground integrated control console 8 receives the position and orientation information of the air-float simulation device 1. Based on the deviation between the position and orientation information of the air-float simulation device 1 and the predetermined docking position, it runs a three-degree-of-freedom simulator control algorithm to calculate the control quantity required to control the movement of the air-float simulation device 1, and converts the control quantity into a control command and sends it to the air-float simulation device 1.

[0039] Step S3: The air flotation simulation device 1 drives the cold jet propulsion unit to work according to the control command, adjusts its own posture, and moves towards the predetermined docking position.

[0040] Step S4: After the air flotation simulation device 1 moves to the predetermined docking position, the ground integrated control console 8 controls the robotic arm 6 to start and perform auxiliary fine-tuning operations on the air flotation simulation device 1, and finally completes the precision docking.

[0041] Therefore, the present invention adopts the above-mentioned space assembly ground test system and method based on air buoyancy simulation, which solves the high cost and high risk problems caused by satellite orbit deviation and attitude loss during space assembly. It eliminates the need for actual space assembly tests, significantly reduces the cost and risk of space assembly tests, and provides a safe, reliable and low-cost ground verification solution for satellite assembly, maintenance and replacement.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A space assembly ground test system based on air-bearing simulation, characterized in that, It includes an air flotation simulation device, a marble platform, a first simulation wall, a second simulation wall, a third simulation wall, a robotic arm, a ground measuring device, and a ground integrated control console; the marble platform is laid horizontally; the first, second, and third simulation walls are perpendicular to each other and fixedly connected to the marble platform; the air flotation simulation device is set on the marble platform and located within the space defined by the first, second, and third simulation walls; the ground integrated control console is set on the side of the marble platform adjacent to the third simulation wall.

2. The space assembly ground test system based on air-bearing simulation according to claim 1, characterized in that, The robotic arm is fixedly mounted on the first simulation wall.

3. The space assembly ground test system based on air-bearing simulation according to claim 1, characterized in that, The ground measurement device is fixedly installed on the first simulation wall, the second simulation wall, and the third simulation wall.

4. The space assembly ground test system based on air-bearing simulation according to claim 1, characterized in that, The ground-based integrated control console receives the position and orientation information of the air-float simulation device from the ground-based measuring device. Based on the position and orientation information, the ground-based integrated control console runs a three-degree-of-freedom simulator control algorithm, generates control commands, and sends them to the air-float simulation device to drive it to adjust its position and orientation. After the air-float simulation device is adjusted to the predetermined position, the ground-based integrated control console controls the robotic arm to perform auxiliary fine-tuning operations on the air-float simulation device to complete the docking.

5. A space assembly ground test system based on air-bearing simulation according to claim 4, characterized in that, The core of the three-degree-of-freedom simulator control algorithm is the three-degree-of-freedom simulator controller, which is an improved discrete PID controller. The improvement lies in setting the control period of the discrete PID controller to 100ms and using the fifth-order finite difference method to calculate the differential term of the discrete PID controller; the specific expression is as follows: ； ； ； ； ； ； in, Indicates the sampling time; Indicates an index variable; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates in Directional control force calculation; express directional proportional gain; Indicates the first Each sampling time Error in direction; express Integral gain in the direction; Indicates from the first From 0 sampling time points to the 1st Each sampling time The cumulative sum of directional errors; express Differential gain in direction; Indicates the first Each sampling time point The differential term estimate of the direction error; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction; Indicates the first Each sampling time Error in direction.

6. The space assembly ground test system based on air-bearing simulation according to claim 1, characterized in that, The air-float simulation device is a three-degree-of-freedom simulator; the actuator of the air-float simulation device consists of eight cold jet propulsion units, which are used to provide reaction thrust to control the position of the air-float simulation device and to provide torque to control the attitude of the air-float simulation device.

7. A space assembly ground test system based on air-bearing simulation according to claim 6, characterized in that, The eight cold jet thrusters are divided into four groups of two, each group consisting of two cold jet thrusters with opposite thrust directions. At the same time, an actuator thrust distribution strategy is adopted to treat the two cold jet thrusters in the same group as a resultant force unit for control distribution, and to ensure that the two cold jet thrusters in the same group cannot work at the same time.

8. A space assembly ground test system based on air-bearing simulation according to claim 6, characterized in that, The nozzle of the cold jet propulsion uses nitrogen as the working fluid, and the flow of the working fluid in the nozzle is theoretically designed based on the assumptions of steady, one-dimensional, isentropic flow; the nozzle of the cold jet propulsion adopts a supersonic nozzle design.

9. A space assembly ground test method for a space assembly ground test system as described in any one of claims 1-8, characterized in that, Includes the following steps: Step S1: Obtain the position and attitude information of the air-float simulation device in real time through the ground measuring device; Step S2: The ground integrated control console receives the position and orientation information of the air-float simulation device. Based on the deviation between the position and orientation information of the air-float simulation device and the predetermined docking position, it runs the three-degree-of-freedom simulator control algorithm to calculate the control quantity required to control the movement of the air-float simulation device, and converts the control quantity into control commands and sends them to the air-float simulation device. Step S3: The air flotation simulation device drives the cold jet propulsion unit to work according to the control command, adjusts its own posture, and moves towards the predetermined docking position. Step S4: After the air flotation simulator moves to the predetermined docking position, the ground integrated control console controls the robotic arm to start and perform auxiliary fine-tuning operations on the air flotation simulator to finally complete the precision docking.

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