Multi-degree-of-freedom intelligent attitude adjustment control system for spacecraft assembly

Abstract

A multi-degree-of-freedom intelligent attitude adjustment control system for spacecraft assembly comprises an external overall control unit, an assembly mechanism, a rotation control unit, a dumping control unit, a four-point fine adjustment unit and an omni-directional moving unit, and the rotation control unit is responsible for 0-360-degree rotation control of the assembly mechanism around a Z axis; the dumping control unit is responsible for controlling the overturning of the general assembly mechanism when the included angle between the horizontal direction and the vertical direction is 0-90 degrees; the four-point fine adjustment unit is responsible for single-point and four-point linkage lifting adjustment in the Z direction of the final assembly mechanism; the omni-directional moving unit is responsible for walking and moving of the final assembly mechanism; the final assembly mechanism is used for bearing and fixing a spacecraft; the external overall control unit is used for controlling the actions of the rotation control unit, the dumping control unit, the four-point fine adjustment unit and the omni-directional moving unit; according to the invention, high-precision and high-reliability multi-degree-of-freedom attitude adjustment and transfer integrated control of the spacecraft is realized.

Description

Technical Field

[0001] This invention relates to a multi-degree-of-freedom intelligent attitude control system for spacecraft assembly, belonging to the field of spacecraft control. Background Technology

[0002] With the steady progress of my country's space station construction, the demand for spacecraft development capabilities has increased more than tenfold. The original assembly-based development model can no longer meet the needs of the situation. It is necessary to fundamentally solve the huge gap between development capabilities and demands, and transform from the traditional manual, single-machine offline assembly model to a multi-agent collaborative model to achieve a high-precision and efficient assembly model with online real-time monitoring, dynamic adjustment, and collaborative clustering.

[0003] Existing multi-degree-of-freedom intelligent attitude control systems for spacecraft assembly rely on decentralized equipment systems. Each unit operates independently, with attitude adjustment, transportation, and fine-tuning lifting completed by different mechanisms. Each operation is independent of the others, and there are situations where hoisting is required during assembly. Frequent action switching and process fragmentation result in low assembly efficiency and difficulty in guaranteeing accuracy. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a multi-degree-of-freedom intelligent attitude control system for spacecraft assembly, so as to realize high-precision and high-reliability attitude adjustment and transportation integrated control of spacecraft.

[0005] The technical solution of this invention is: a multi-degree-of-freedom intelligent attitude control system for spacecraft assembly, comprising: The external overall control unit, the assembly mechanism, and the slewing control unit, tilting control unit, four-point fine-tuning unit, and omnidirectional movement unit mounted on the assembly mechanism, wherein: The assembly mechanism is used to support and secure spacecraft. The slewing control unit is responsible for controlling the rotation of the assembly mechanism around the Z-axis from 0 to 360 degrees. The tilt control unit is responsible for controlling the tilting of the assembly mechanism within the range of 0° to 90° between the horizontal and vertical angles. The four-point fine-tuning unit is responsible for the single-point and four-point linkage lifting and lowering adjustment of the assembly mechanism in the Z direction; The omnidirectional mobile unit is responsible for the movement and travel of the final assembly mechanism; The external overall control unit controls the movements of the slewing control unit, tilting control unit, four-point fine-tuning unit, and omnidirectional movement unit; The Z direction is the vertical direction.

[0006] Preferably, the rotary control unit has two working modes: continuous rotary and jog rotary. Continuous rotary is divided into open-loop continuous rotary and position closed-loop continuous rotary, while jog rotary is a fixed angle micro-adjustment. The slewing control unit includes: a motion controller, a slewing motor, and a slewing driver, an absolute encoder, and an angle encoder mounted on the slewing motor, wherein: The motion controller receives instructions from the external overall control unit, calculates the motion parameters of the rotary motor, and sends them to the rotary driver via the TWINCAT interface to complete the driving of the rotary motor. The rotary motor is equipped with a 24-bit absolute encoder, which feeds back the motor speed data to the rotary driver, which completes the speed closed loop. The angle encoder is installed on the angle measuring gear of the assembly mechanism and feeds back the angle data to the motion controller to complete the position closed loop.

[0007] Preferably, the tilt control unit has two working modes: continuous tilting and inching fine adjustment. Continuous tilting is divided into open-loop continuous tilting and position closed-loop continuous tilting. The tilt control unit includes: an action controller, a tilt driver, a tilt motor, a tilt encoder, a proximity switch, and a limit switch; wherein: The motion controller receives instructions from the external overall control unit, calculates the motion parameters of the tilting motor, and sends them to the tilting motor driver. The tilting motor driver sends control signals to the tilting motor according to the speed and direction information contained in the control instructions, controlling the tilting mechanism to move to the target angle. The tilt encoder is a feedback element that measures the tilt angle and sends the tilt position to the motion controller; When the assembly mechanism is rotated into position, the proximity switch is triggered, and the tilting control unit stops the rotation. When the assembly mechanism is rotated to the limit position, the limit switch is triggered, and the tilting control unit is de-energized, stops the movement, and remains in that position. At the same time, mechanical limit measures are set at the extreme positions. If both the proximity switch and the limit switch are damaged, the mechanical limit can restrict the flipping action.

[0008] Preferably, the four-point fine-tuning unit includes: a fine-tuning controller, a pressure sensor, a tilt sensor, a leg motor driver, and a leg motor; wherein: During the leveling process, the fine-tuning controller receives instructions from the external overall control unit, calculates the motion parameters of each outrigger motor based on the data feedback from the pressure sensor and tilt sensor installed on the assembly mechanism, and sends them to each outrigger motor driver to drive the outrigger motor to rotate and complete the automatic leveling. Inductive proximity switches are installed at the upper and lower limit positions of the assembly mechanism to realize electrical limit of the lifting position, and mechanical limit blocks are installed at the limit positions to provide double limit protection for the four-point fine adjustment unit.

[0009] Preferably, the omnidirectional mobility unit includes: a walking controller, a laser scanning sensor, a wheel motor, a wheel motor driver, and an energy module; wherein: The energy module uses an inverter to convert the 48V DC power from the battery into 380V AC power to power the omnidirectional mobile unit. When the energy module fails, it uses the mains power to directly power the walking operation. After receiving the control command from the external overall control unit, the walking controller calculates the motion parameters of each wheel motor. The wheel motor driver provides control signals to the wheel motor based on the speed and steering information contained in the control command, driving the wheel motor to rotate. During omnidirectional movement, the laser scanning sensor scans for obstacles in the surrounding area. When an obstacle is detected in the set stop area, the travel controller sends an emergency stop command to the wheel motor driver, controlling the wheel motor to stop urgently and simultaneously cutting off the power to the wheel motor driver. When the omnidirectional moving unit malfunctions and cannot move autonomously, the braking mode can be released electronically or the mechanical brake can be unlocked, allowing the assembly mechanism to be moved by external force.

[0010] Preferably, the slewing control unit and the tilting control unit share the same motion controller; The motion controller uses a PLC programmed based on TwinCat3, which can support hardware scanning and parameter configuration, control program writing and function implementation, variable establishment and management, and axis parameter setting. Hardware scanning and parameter configuration mainly completes the scanning of all hardware, including: angle encoder, tilt encoder, rotary driver and tilt driver; the hardware is connected to the PLC in series via EtherCat bus and RS232 bus, the PLC connects the hardware with the control program by scanning the devices on the bus, and configures the parameters of the scanned hardware according to the specific hardware situation; The program writing and function implementation module establishes three main functions, including: encoder data reading and processing, tilting and rotation function implementation, and external communication establishment and data transmission. Variable creation and management involves the creation and management of all variables used in the entire control program, including global variables, I / O variables, and axis variables; The shaft parameter settings include: shaft rotation direction setting, shaft limit setting, shaft reduction ratio setting, as well as the shaft's maximum speed, acceleration, and whether it is a modal shaft.

[0011] Preferably, the walking controller and the fine-tuning controller use a combination of an ARM data analysis subunit and an FPGA motion control subunit as the hardware platform for the controller, wherein: The ARM data analysis subunit receives control commands sent by the external overall control unit, parses and processes them, and then transmits the signals to the FPGA motion control subunit. It also completes data interaction with the external overall control unit and motion controller, realizes status monitoring of the energy module and laser scanning sensor, and can output alarm control signals.

[0012] Compared with the prior art, the present invention has the following advantages: The multi-degree-of-freedom intelligent attitude adjustment control system of this invention integrates the functions of rotation, tilting, fine adjustment, and omnidirectional movement required in the spacecraft assembly process, reducing the hoisting requirements caused by functional separation. It offers diversified operation modes, supporting multi-dimensional human-machine interaction via host computer, handheld device, and control box panel, meeting control requirements under various working conditions. Interlocking measures are implemented at both the hardware power supply and software control levels for each operation mode and function selection to prevent malfunctions of actuators during spacecraft assembly. The rotation control unit, tilting control unit, and fine adjustment control unit are equipped with electrical and mechanical limit safety redundancy protection measures, and redundant drive emergency unlocking mechanisms are set in each functional unit, achieving high-precision, high-efficiency, and high-reliability integrated control of multi-degree-of-freedom attitude adjustment and transport of the spacecraft. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the control system architecture of the present invention; Figure 2 This is the power supply and distribution diagram for the present invention; Figure 3 This is a layout diagram of the control cabinet panel of the present invention; Figure 4 This is a layout diagram of the handheld controller of the present invention; Figure 5 This is a schematic diagram of the omnidirectional mobile interface of the host computer in this invention. Detailed Implementation

[0014] This invention discloses a multi-degree-of-freedom attitude adjustment control system for spacecraft assembly, the control system architecture of which is as follows: Figure 1 As shown. The control system consists of an external overall control unit, a slewing control unit, a tilting control unit, a four-point fine-tuning unit, and an omnidirectional movement unit. The power supply and distribution methods of each unit are as follows: Figure 2 As shown. The control system adopts a distributed control architecture, with three controllers—an action controller, a walking controller, and a fine-tuning controller—collaborating to complete the functions of the four units. Data transmission between the controllers is completed via RS232 and CAN bus, and all controllers support multi-dimensional human-machine interaction operations via host computer, handheld device, and control box panel, thereby realizing high-precision and high-reliability integrated control of spacecraft attitude adjustment and transportation.

[0015] The technical solution of the present invention is as follows: To achieve the above objectives, a multi-degree-of-freedom attitude adjustment and control system for large spacecraft is proposed. The control system includes a rotation control unit, a tilt control unit, a four-point fine-tuning unit, and an omnidirectional movement unit.

[0016] The external overall control unit includes a control cabinet operation panel, a handheld controller, and a host computer. All three control methods are interlocked at the hardware power supply and software control levels. The control cabinet operation panel layout is as follows: Figure 3 As shown, the functional layout of the handheld controller is as follows: Figure 4 As shown, the host computer has multiple operating interfaces. Taking the omnidirectional mobile interface as an example, such as... Figure 5 As shown.

[0017] The aforementioned slewing control unit, controlled by an action controller, manages the mechanism's rotation from 0° to 360° along the Z-axis. The main structure of the slewing unit comprises a drive unit, a transmission unit, and an angle encoder. It operates in two modes: continuous slewing and inching slewing. Continuous slewing is further divided into open-loop continuous slewing and closed-loop position continuous slewing, while inching slewing involves a fixed 0.1° micro-adjustment. The action controller communicates with the slewing motor driver via a TwinCAT interface to drive the slewing motor. The slewing motor is internally equipped with a 24-bit absolute encoder, whose data is fed back to the slewing motor driver, enabling the driver to complete the speed closed loop. An angle encoder is mounted on the angle measuring gear on the assembly mechanism, and its angle data is fed back to the action function controller to complete the position closed loop.

[0018] The tilting control unit, controlled by an action controller, controls the horizontal and vertical tilting of the mechanism from 0 to 90 degrees. It features two operating modes: continuous tilting and inching fine-tuning. Continuous tilting is divided into open-loop continuous tilting and closed-loop continuous tilting, while inching fine-tuning provides a fixed 0.1° micro-adjustment. The tilting control unit uses a tilt encoder as the feedback element for measuring the tilting angle. Proximity switches and limit switches are installed on the tilting mechanism's base frame. Upon reaching the tilting position, the proximity switch triggers, stopping the tilting module's tilting motion. Limit switches are located at extreme positions; triggering them de-energizes the mechanism, stopping the movement and maintaining the position. Simultaneously, mechanical limit measures are implemented at the extreme positions. If both the proximity switch and the limit switch are damaged, the mechanical limit restricts the tilting action.

[0019] The slewing control unit and the tilting control unit can share a single motion controller.

[0020] The four-point fine-tuning unit consists of a fine-tuning controller, a pressure sensor, a tilt sensor, a leg motor driver, and leg motors. The fine-tuning controller performs single-point and four-point linkage lifting and lowering adjustments in the Z-direction of the height of the fine-tuning mechanism. During the leveling process, the fine-tuning controller calculates the motion parameters of each leg motor based on data feedback from the pressure and tilt sensors and sends them to each leg motor driver. Inductive proximity switches are installed at the upper and lower limit positions of each mechanism in the four-point fine-tuning unit to achieve electrical limits on the lifting and lowering positions, and mechanical limit blocks are installed at the corresponding positions to achieve mechanical limits on the lifting and lowering fine-tuning positions, thereby achieving dual limit protection for the four-point fine-tuning unit.

[0021] The omnidirectional mobility unit consists of a walking controller, a laser scanning sensor, wheel train motors, wheel train motor drivers, and an energy module. The omnidirectional mobility unit is powered by a 48V DC battery converted to 380V AC via an inverter. In case of energy system failure, it can be powered directly from the mains to complete the movement operation. After receiving control commands from the host computer or handheld device, the walking controller calculates the motion parameters of each wheel train. The wheel train motor drivers provide control signals to the wheel train motors based on the speed and steering information contained in the control commands to drive the motors to rotate. The laser scanning sensor is used to scan for obstacles around the omnidirectional movement. When an obstacle is detected in the designated stop zone, the walking controller sends an emergency stop command to the wheel train motor drivers, controlling the wheel train to stop urgently. Simultaneously, the sensor outputs an I / O signal to power off the wheel train motor drivers, employing a hardware and software dual backup method to achieve device shutdown. When the omnidirectional mobility unit malfunctions and cannot move autonomously, the braking mode can be released electronically or the mechanical brakes can be unlocked, allowing the device to be moved by external force.

[0022] The motion controller uses a PLC programmed based on TwinCat3 to implement rotation and tilt control. The underlying control system architecture includes hardware scanning and parameter configuration, program writing and function implementation, variable establishment and management, and axis parameter setting. The hardware scanning and parameter configuration module mainly completes the scanning of all hardware, including angle encoders, tilt encoders, rotation drivers, and tilt drivers. Each piece of hardware is connected to the PLC via EtherCat and RS232 buses. The PLC connects the hardware and software by scanning the devices on the bus and configures the parameters of the scanned hardware according to the specific hardware requirements. The program writing and function implementation module establishes three main functions: encoder data reading and processing, tilt and rotation function implementation, and external communication establishment and data transmission. The variable establishment and management module mainly involves the establishment and management of all variables used in the entire control program, including global variables, I / O variables, and axis variables. Axis parameter setting includes setting the axis rotation direction, axis limit settings, axis reduction ratio settings, and other parameters such as maximum speed, acceleration, and whether it is a modal axis.

[0023] Both the walking controller and the fine-tuning controller use an ARM data analysis subunit and an FPGA motion control unit as the hardware platform for the controller. The ARM receives the control commands sent by the host computer, parses and processes them, and then transmits the signals to the FPGA motion control. It also completes data interaction with the host computer and the motion controller to realize the status monitoring of the energy system and the laser scanning sensor, as well as the output of alarm control signals.

[0024] Example: The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: A multi-degree-of-freedom attitude adjustment control system for a large spacecraft features interlocked motions in its rotation control unit, tilt control unit, fine-tuning control unit, and omnidirectional movement unit. The specific workflow is as follows: (1) Turn the charging / power off / power on switch in the vehicle body function control area on the control cabinet to the power on position to start the omnidirectional moving unit. At this time, the host computer will be powered on and the walking controller will send information such as control mode, fault code, battery power, and communication status to the host computer.

[0025] (2) Turn the control cabinet function selection area switch to the moving position and the controller selection area switch to the host computer or handheld device position to complete the control mode selection.

[0026] (3) The walking controller of the omnidirectional mobile unit receives the control signal sent by the host computer or handheld device, and sends the calculated motion parameters of each wheel system to the 8 wheel system motor drivers. The wheel system motor drivers send the control signal to the corresponding wheel system motor according to the speed and direction information contained in the control command, so as to drive the motor to rotate and control the device to move to the target position.

[0027] (4) After the equipment is moved to the target position, turn the charging / shutdown / power-on switch in the vehicle body function control area on the control cabinet to the power off position, shut down the omnidirectional movement unit, connect the mains power supply cable to the control cabinet, turn on the power switch in the turntable power control area, and press the turntable power-on button. The system rotation control unit, tilt control unit and fine adjustment control unit will start, the motion controller, walking controller and fine adjustment controller will start, and the host computer will be powered on.

[0028] (5) Turn the control cabinet function selection area switch to the fine adjustment position and turn the controller selection area switch to the host computer, panel or handheld device position to complete the control mode selection.

[0029] (6) When fine-tuning control is performed using a host computer or handheld device, the walking controller of the omnidirectional movement unit receives the control signal sent by the control terminal and sends the signal to the fine-tuning controller. The fine-tuning controller calculates the motion parameters of each outrigger motor and sends them to the four outrigger motor drivers. The outrigger motor drivers send control signals to the corresponding outrigger motors according to the speed and direction information contained in the control command, so as to drive the motors to rotate and control the fine-tuning mechanism to rise to the target height.

[0030] (7) When the chassis panel is used for fine-tuning control, the fine-tuning controller directly receives the speed, direction and start / stop I / O signals controlled by the panel buttons, calculates the motion parameters of each outrigger motor, and sends them to the four outrigger motor drivers. The outrigger motor drivers send control signals to the corresponding outrigger motors according to the speed and direction information contained in the control instructions, so as to drive the motors to rotate and control the fine-tuning mechanism to rise to the target height.

[0031] (8) The tilt sensor of the fine-tuning control unit collects the angle information of the bearing plane of the equipment in the X, Y and Z directions and sends the information to the fine-tuning controller. The fine-tuning controller analyzes the motion parameters of each outrigger motor according to the angle information sent by the tilt sensor and the pressure information of each outrigger sent by the pressure sensor, and sends them to the four outrigger motor drivers. The outrigger motor drivers send control signals to the corresponding outrigger motors according to the speed and direction information contained in the control command, drive the motors to rotate, and control the fine-tuning mechanism to complete the automatic leveling.

[0032] (9) After the spacecraft and equipment docking is completed, turn the control cabinet function selection area switch to the tilt position and turn the controller selection area switch to the host computer, panel or handheld device position to complete the control mode selection.

[0033] (10) When the host computer is used for control, the motion controller receives the target speed and target position control instructions sent by the host computer, calculates the motion parameters of the tilting motor, and sends them to the tilting motor driver. The tilting motor driver sends the control signal to the tilting motor according to the speed and direction information contained in the control instructions. The tilting angle information is collected in real time by the tilting encoder and sent to the motion controller to complete the position closed-loop control of the tilting motion and control the tilting mechanism to move precisely to the target angle.

[0034] (11) When using handheld device control, the walking controller of the omnidirectional motion control unit receives the target speed and tilting direction command sent by the handheld device, sends the command to the motion controller, the motion controller calculates the motion parameters of the tilting motor and sends them to the tilting motor driver, the tilting motor driver sends the control signal to the tilting motor according to the speed and direction information contained in the control command, completes the open-loop speed control of the tilting motion, and controls the tilting mechanism to move to the target angle.

[0035] (12) When the tilting control is performed using the chassis panel, the motion controller directly receives the speed, direction and start / stop I / O signals controlled by the panel buttons, calculates the tilting motor motion parameters, and sends them to the tilting motor driver. The tilting motor driver sends the control signal to the tilting motor according to the speed and direction information contained in the control command, completes the open-loop speed control of the tilting motion, and controls the tilting mechanism to move to the target angle.

[0036] (13) After completing the tilting control operation, turn the control cabinet function selection area switch to the rotary position and turn the controller selection area switch to the host computer, panel or handheld device position to complete the control mode selection.

[0037] (14) When the host computer is used for control, the motion controller receives the target speed and target position control instructions sent by the host computer, calculates the motion parameters of the rotary motor, and sends them to the rotary motor driver. The rotary motor driver sends the control signal to the rotary motor according to the speed and direction information contained in the control instructions. The angle encoder configured by the angle measuring gear feeds back the real-time collected rotation angle data to the motion controller, completes the position closed-loop control of the rotation motion, and controls the rotary mechanism to rotate precisely to the target angle.

[0038] (15) When using handheld device control, the walking controller of the omnidirectional motion control unit receives the target speed and turning direction command sent by the handheld device, sends the command to the motion controller, the motion controller calculates the motion parameters of the rotary motor and sends them to the rotary motor driver, the rotary motor driver sends the control signal to the rotary motor according to the speed and direction information contained in the control command, completes the open-loop speed control of the rotary motion, and controls the rotary mechanism to move to the target angle.

[0039] (16) When the chassis panel is used for rotation control, the motion controller directly receives the speed, direction and start / stop I / O signals controlled by the panel buttons, calculates the motion parameters of the rotary motor, and sends them to the rotary motor driver. The rotary motor driver sends the control signal to the rotary motor according to the speed and direction information contained in the control command, completes the open-loop speed control of the rotation motion, and controls the rotary mechanism to move to the target angle.

[0040] In summary, this invention provides a multi-degree-of-freedom intelligent attitude control system for spacecraft assembly. The control system consists of an external overall control unit, a rotation control unit, a tilt control unit, a four-point fine-tuning unit, and an omnidirectional movement unit. The operation of each unit can be completed by the host computer, a handheld controller, and the buttons on the control box panel, realizing efficient and safe transportation and high-precision rapid adjustment of the spacecraft in the assembly process.

[0041] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A multi-degree-of-freedom intelligent attitude control system for spacecraft assembly, characterized in that... include: The external overall control unit, the assembly mechanism, and the slewing control unit, tilting control unit, four-point fine-tuning unit, and omnidirectional movement unit mounted on the assembly mechanism, wherein: The assembly mechanism is used to support and secure spacecraft. The slewing control unit is responsible for controlling the rotation of the assembly mechanism around the Z-axis from 0 to 360 degrees. The tilt control unit is responsible for controlling the tilting of the assembly mechanism within the range of 0° to 90° between the horizontal and vertical angles. The four-point fine-tuning unit is responsible for the single-point and four-point linkage lifting and lowering adjustment of the assembly mechanism in the Z direction; The omnidirectional mobile unit is responsible for the movement and travel of the final assembly mechanism; The external overall control unit controls the movements of the slewing control unit, tilting control unit, four-point fine-tuning unit, and omnidirectional movement unit; The Z direction is the vertical direction.

2. The multi-degree-of-freedom intelligent attitude control system for spacecraft assembly according to claim 1, characterized in that: The rotary control unit has two working modes: continuous rotary and jogging rotary. Continuous rotary is divided into open-loop continuous rotary and position closed-loop continuous rotary, while jogging rotary is a fixed angle micro-adjustment. The slewing control unit includes: a motion controller, a slewing motor, and a slewing driver, an absolute encoder, and an angle encoder mounted on the slewing motor, wherein: The motion controller receives instructions from the external overall control unit, calculates the motion parameters of the rotary motor, and sends them to the rotary driver via the TWINCAT interface to complete the driving of the rotary motor. The rotary motor is equipped with a 24-bit absolute encoder, which feeds back the motor speed data to the rotary driver, which completes the speed closed loop. The angle encoder is installed on the angle measuring gear of the assembly mechanism and feeds back the angle data to the motion controller to complete the position closed loop.

3. A multi-degree-of-freedom intelligent attitude control system for spacecraft assembly according to claim 2, characterized in that: The tilt control unit has two working modes: continuous tilting and inching fine adjustment. Continuous tilting is divided into open-loop continuous tilting and position closed-loop continuous tilting. The tilt control unit includes: an action controller, a tilt driver, a tilt motor, a tilt encoder, a proximity switch, and a limit switch; wherein: The motion controller receives instructions from the external overall control unit, calculates the motion parameters of the tilting motor, and sends them to the tilting motor driver. The tilting motor driver sends control signals to the tilting motor according to the speed and direction information contained in the control instructions, controlling the tilting mechanism to move to the target angle. The tilt encoder is a feedback element that measures the tilt angle and sends the tilt position to the motion controller; When the assembly mechanism is rotated into position, the proximity switch is triggered, and the tilting control unit stops the rotation. When the assembly mechanism is rotated to the limit position, the limit switch is triggered, and the tilting control unit is de-energized, stops the movement, and remains in that position. At the same time, mechanical limit measures are set at the extreme positions. If both the proximity switch and the limit switch are damaged, the mechanical limit can restrict the flipping action.

4. A multi-degree-of-freedom intelligent attitude control system for spacecraft assembly according to claim 3, characterized in that: The four-point fine-tuning unit includes: a fine-tuning controller, a pressure sensor, a tilt sensor, a leg motor driver, and a leg motor; wherein: During the leveling process, the fine-tuning controller receives instructions from the external overall control unit, calculates the motion parameters of each outrigger motor based on the data feedback from the pressure sensor and tilt sensor installed on the assembly mechanism, and sends them to each outrigger motor driver to drive the outrigger motor to rotate and complete the automatic leveling. Inductive proximity switches are installed at the upper and lower limit positions of the assembly mechanism to realize electrical limit of the lifting position, and mechanical limit blocks are installed at the limit positions to provide double limit protection for the four-point fine adjustment unit.

5. A multi-degree-of-freedom intelligent attitude control system for spacecraft assembly according to claim 4, characterized in that: The omnidirectional mobility unit includes: a walking controller, a laser scanning sensor, a wheel motor, a wheel motor driver, and an energy module; wherein: The energy module uses an inverter to convert the 48V DC power from the battery into 380V AC power to power the omnidirectional mobile unit. When the energy module fails, it uses the mains power to directly power the walking operation. After receiving the control command from the external overall control unit, the walking controller calculates the motion parameters of each wheel motor. The wheel motor driver provides control signals to the wheel motor based on the speed and steering information contained in the control command, driving the wheel motor to rotate. During omnidirectional movement, the laser scanning sensor scans for obstacles in the surrounding area. When an obstacle is detected in the set stop area, the travel controller sends an emergency stop command to the wheel motor driver, controlling the wheel motor to stop urgently and simultaneously cutting off the power to the wheel motor driver. When the omnidirectional moving unit malfunctions and cannot move autonomously, the braking mode can be released electronically or the mechanical brake can be unlocked, allowing the assembly mechanism to be moved by external force.

6. A multi-degree-of-freedom intelligent attitude control system for spacecraft assembly according to claim 3, characterized in that: The slewing control unit and the tilting control unit share the same motion controller; The motion controller uses a PLC programmed based on TwinCat3, which can support hardware scanning and parameter configuration, control program writing and function implementation, variable establishment and management, and axis parameter setting. Hardware scanning and parameter configuration mainly completes the scanning of all hardware, including: angle encoder, tilt encoder, rotary driver and tilt driver; the hardware is connected to the PLC in series via EtherCat bus and RS232 bus, the PLC connects the hardware with the control program by scanning the devices on the bus, and configures the parameters of the scanned hardware according to the specific hardware situation; The program writing and function implementation module establishes three main functions, including: encoder data reading and processing, tilting and rotation function implementation, and external communication establishment and data transmission. Variable creation and management involves the creation and management of all variables used in the entire control program, including global variables, I / O variables, and axis variables; The shaft parameter settings include: shaft rotation direction setting, shaft limit setting, shaft reduction ratio setting, as well as the shaft's maximum speed, acceleration, and whether it is a modal shaft.

7. A multi-degree-of-freedom intelligent attitude control system for spacecraft assembly according to claim 5, characterized in that: The walking controller and fine-tuning controller use a combination of an ARM data analysis subunit and an FPGA motion control subunit as the hardware platform for the controller, wherein: The ARM data analysis subunit receives control commands sent by the external overall control unit, parses and processes them, and then transmits the signals to the FPGA motion control subunit. It also completes data interaction with the external overall control unit and motion controller, realizes status monitoring of the energy module and laser scanning sensor, and can output alarm control signals.

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