Lunar surface mobile general GNC semi-physical test system and method based on real-time simulation

Abstract

The invention discloses a lunar surface mobile general GNC semi-physical test system and method based on real-time simulation. Comprising a lunar surface dynamics simulation subsystem for modeling a mobile platform, a sensor, a lunar surface terrain, a wheel-land action relationship and the like, performing movement control according to a control instruction, and outputting real movement responses such as poses and the like; the lunar surface scene rendering subsystem is used for modeling lunar surface meteorite craters, sloping fields, stones and the like, rendering typical lunar surface scenes and outputting images and point cloud information; and the GNC control subsystem is used for performing GNC closed-loop simulation according to the input movement response and the image point cloud information, realizing functional simulation such as navigation positioning and attitude determination, obstacle perception and the like, and resolving and outputting a control instruction through a control law. Information interaction is carried out among the subsystems through a serial port or the Ethernet, through clock synchronization and modular design, the sub-modules are independent and replaceable, universality and high precision are considered, the problem that a lunar surface test is not feasible is effectively solved, and a reliable lunar surface GNC verification means is provided.

Description

Technical Field

[0001] This invention relates to a general-purpose GNC semi-physical test system and method for lunar surface movement based on real-time simulation, belonging to the field of semi-physical simulation technology. Background Technology

[0002] The lunar mobile platform, as the carrier for lunar surface exploration, is crucial to the successful implementation of lunar exploration missions and must possess safe, stable, and long-term operating capabilities. The GNC control system, as the sole survivability guarantee for lunar surface movement, is of paramount importance.

[0003] However, the lunar environment differs significantly from the Earth's. The low gravity and soft, low-adhesion lunar soil of the Moon make tires highly susceptible to slippage, causing tire force to easily reach saturation. During high-speed travel on the bumpy lunar surface, the mobile platform frequently experiences wheel lift-off, resulting in sudden changes in vehicle status. Furthermore, the lunar surface is an unstructured environment with poor texture and intense lighting, offering limited scene features and texture variations. The interaction between the wheels and the Earth significantly impacts the control performance of the mobile platform, and scene features are crucial inputs for environmental perception, navigation, positioning, and attitude determination. The vast differences between the Earth and lunar environments present new challenges to validating the effectiveness of the GNC control algorithm.

[0004] Currently, a common ground-based verification method involves constructing a simulated lunar environment and conducting multiple real-vehicle tests. To simulate the effects of low gravity, mobile platform suspension tests or equivalent test vehicles under ground gravity conditions are often used. However, neither suspension tests nor equivalent test vehicles can simulate the wheel-soil interaction under low gravity conditions, resulting in high testing costs, long preparation times, and limited simulation accuracy. Given the inability to conduct real-vehicle tests on the lunar surface, building a high-fidelity hardware-in-the-loop simulation system for closed-loop testing has become the optimal solution among feasible options. Currently, ground-based mobile system GNC simulation systems are mostly used in the field of autonomous driving, primarily focusing on GNC control of vehicles on urban roads. They lack real lunar surface data, and more importantly, the soil models are hard road surface models, unable to simulate the mechanical properties of soft lunar soil. While using discrete element methods to model lunar soil can ensure model accuracy, it suffers from poor simulation real-time performance and cannot achieve GNC closed-loop simulation. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art, provide a semi-physical test system and method for lunar surface movement general GNC based on real-time simulation, and provide a reliable means for dynamic closed-loop verification of lunar surface GNC.

[0006] The technical solution of this invention is: This invention discloses a general-purpose GNC semi-physical experimental system for lunar surface movement based on real-time simulation, comprising: The lunar dynamics simulation subsystem includes models of the mobile platform, sensors, lunar terrain, and wheel-to-ground interaction; it performs movement manipulation based on control commands sent by the GNC control subsystem, outputs the movement response of the lunar mobile platform, and provides data to the GNC control subsystem and the lunar scene rendering subsystem. The lunar scene rendering subsystem renders the lunar scene based on the movement response of the lunar mobile platform, outputs the image and point cloud information under the current vision, and sends it to the GNC control subsystem. The GNC control subsystem performs GNC closed-loop simulation based on the lunar surface mobile platform's movement response, images, and point cloud information. This simulation enables navigation, positioning, attitude determination, and obstacle perception functions. Through control law calculation, it outputs control commands to the lunar surface dynamics simulation subsystem.

[0007] Furthermore, in the above system, the lunar surface dynamics simulation subsystem includes a lunar surface moving platform simulation module, a wheel-soil dynamics simulation module, a sensor simulation module, a terrain simulation module, and an obstacle simulation module; The lunar surface moving platform simulation module models the moving platform's external parameters, mass characteristics, suspension characteristics, actuator characteristics, and tire characteristics respectively. Based on the actual motor selection and drive controller control algorithm, it introduces execution rate of change saturation constraints, actuation delay, second-order inertial response simulation of the motor, and execution amplitude limiting in the actuator response simulation. The wheel-soil dynamics simulation module models the soft characteristics of lunar soil, reflects the real tread deformation and lunar soil pressure during the movement of the mobile platform, and simulates tire slippage and sinking phenomena. The sensor simulation module models the inertial measurement unit and supports the output of acceleration and angular velocity data. The terrain simulation module builds a three-dimensional terrain model of the lunar surface based on real lunar surface terrain data. The obstacle simulation module models obstacles and simulates the dynamic changes in attitude and velocity of the mobile platform after it comes into contact with an obstacle by adding contact collisions.

[0008] Furthermore, in the aforementioned system, the lunar scene rendering subsystem includes a terrain simulation module, an obstacle simulation module, a lighting simulation module, and a sensor simulation module. The terrain simulation module builds a three-dimensional lunar terrain scene model based on real lunar terrain data. The obstacle simulation module models lunar craters, slopes, and rocks. The lighting simulation module adaptively updates lighting parameters based on changes in the solar altitude angle, simulating extreme lunar lighting and reproducing the contrast between light and dark areas, shadow details, and changes in lighting direction on the lunar surface. The sensor simulation module acquires actual images and point cloud data by setting sensor field of view, line count, and focal length parameters based on the actual installation positions and angles of the camera and lidar on the lunar moving platform.

[0009] Furthermore, in the above system, the lunar surface dynamics simulation subsystem and the lunar surface scene rendering subsystem are configured with the same terrain file; the lunar surface dynamics simulation subsystem and the lunar surface scene rendering subsystem exchange information via Ethernet; the lunar surface dynamics simulation subsystem and the GNC control subsystem communicate via serial port; and the lunar surface scene rendering subsystem and the GNC control subsystem communicate via Ethernet.

[0010] Furthermore, in the above system, the GNC control subsystem includes a mode selection module, an operation interaction module, a trajectory planning module, an obstacle recognition module, a navigation module, a tracking control module, and an ESP module.

[0011] Furthermore, in the above system, the operation interaction module converts the operator's operational intentions into operational instructions for the lunar mobile platform through the operation tools; in remote operation mode, it converts the control actions into motion control instructions for the entire mobile platform; and in manned lunar mode, it converts the driver's joystick operation into quantifiable human driving intentions. The obstacle recognition module uses image and point cloud information to identify objects that affect driving, including lunar craters, slopes, and rocks. The trajectory planning module, in lunar autonomous driving mode, plans feasible trajectories in real time based on preset target points and surrounding environmental information, and obtains trajectory planning results. The navigation module uses image, point cloud and inertial group data to perform fusion navigation and positioning to determine the position, attitude, orientation and velocity information of the lunar moving platform; The tracking control module tracks the desired position, speed, and heading of the mobile platform based on the trajectory planning results. The ESP module applies stabilization control to the mobile platform based on its current driving status to prevent instability on the soft lunar surface.

[0012] Furthermore, the system also includes an inertial measurement unit, a camera, and a lidar; among which, The lunar dynamics simulation subsystem outputs acceleration and angular velocity information, which is then injected into the ground measurement port of the inertial measurement unit via serial communication. The inertial measurement unit (IMU) acquires acceleration and angular velocity information from the ground measuring port and then sends the IMU measurement information to the GNC control subsystem via serial communication. The lunar scene rendering subsystem outputs images and point cloud information, which are then converted to LVDS via Ethernet and then transmitted to the camera and LiDAR via LVDS respectively. The camera and lidar send the received images and point cloud information to the GNC control subsystem via LVDS. Furthermore, in the above system, the GNC control subsystem outputs control commands for driving, steering, and braking of each actuator to the lunar dynamics simulation subsystem; the mobile platform in the lunar dynamics simulation subsystem moves and steers according to the control commands.

[0013] Furthermore, in the above system, the lunar scene rendering subsystem outputs the image and point cloud data acquired by the mobile platform in its current pose to the GNC control subsystem; The GNC control subsystem sends clock synchronization signals to the lunar dynamics simulation subsystem via a serial port; it connects to the operating joystick via a USB serial port and converts the operator's intentions into operating commands for the lunar moving platform through the operation interaction module; and it communicates with the inertial measurement unit, camera, and lidar via serial port, LVDS, and other means to acquire the necessary sensor data.

[0014] This invention discloses a control method for a real-time simulation-based general-purpose GNC semi-physical experimental system for lunar surface movement, characterized by comprising: The GNC control subsystem selects the operating mode to be executed. Depending on the operating mode, inertial navigation data, image data, and point cloud data are acquired from external interfaces. The GNC control subsystem converts the operation signals output by the joystick into joystick operation commands. The GNC control subsystem identifies obstacles affecting movement based on image and point cloud data, and obtains obstacle identification results. The GNC control subsystem performs navigation calculations based on the input inertial data, image data, and point cloud data to determine the current driving status of the mobile platform. The GNC control subsystem plans a feasible trajectory based on the obstacle recognition results and the current driving status of the mobile platform; The desired position, speed, and heading of the mobile platform are calculated for tracking control to obtain the tracking control results; Based on the joystick operation commands and tracking control results, and considering the current driving state of the mobile platform, control commands for the actuators are calculated. The GNC control subsystem sends a clock synchronization signal to the lunar dynamics simulation subsystem via a serial port. The lunar dynamics simulation subsystem synchronizes with the GNC control subsystem based on the clock synchronization signal. The mobile platform moves according to control commands to obtain the latest driving status; The lunar dynamics simulation subsystem outputs updated acceleration and angular velocity information to the GNC control subsystem based on the latest driving status, and outputs the position and attitude of the mobile platform to the lunar scene rendering subsystem. The lunar scene rendering subsystem updates the image and point cloud data from the current viewpoint based on position and orientation; The lunar dynamics simulation subsystem outputs the position, attitude, orientation, and velocity of the mobile platform, as well as the position and size information of obstacles, to the GNC control subsystem. The GNC control subsystem verifies the accuracy of the navigation and obstacle recognition modules based on the position, attitude, orientation, speed of the mobile platform, and the position and size information of obstacles.

[0015] The advantages of this invention over the prior art are as follows: (1) This invention provides a lunar surface mobile general-purpose GNC semi-physical test system based on real-time simulation. It fully considers the dynamic changes of the soil surface caused by the difference between the Earth and the Moon environment, as well as the characteristics of the texture-poor unstructured environment. In the simulation system, soil surface parameters, terrain structure, lighting conditions, sensor models, and mobile platform models are all modeled with real data. Through hardware-in-the-loop and human-computer interaction architecture design, it reproduces the characteristics of single-machine measurement error and human operation lag, and realizes the full-process closed-loop verification of the GNC algorithm in the dynamic scenario of the lunar surface. It has the characteristics of high simulation accuracy and strong real-time performance. Through modular design, it takes into account both versatility and high fidelity, ensuring the effectiveness of the experiment and the feasibility of lunar surface application, shortening the test cycle, and significantly reducing mission risks and costs.

[0016] (2) This invention proposes a lunar surface mobile universal GNC semi-physical test system based on real-time simulation, including a lunar surface dynamics simulation subsystem, which models the soft and low-adhesion characteristics of lunar soil and drives the lunar surface mobile platform according to control input commands to simulate its real response; a lunar surface scene rendering subsystem, which models typical lunar surface scenes and three-dimensional terrain to improve the realism of the simulation scene; and a GNC control subsystem, which realizes guidance, navigation and control closed-loop simulation according to different working modes and outputs control commands. The lunar surface mobile universal GNC simulation system fully considers the characteristics of the lunar environment, the configuration design of the lunar surface mobile platform, data communication lag, sensor measurement accuracy, and actuator response capability, etc. It has high simulation accuracy and strong real-time performance. Through modular design, each sub-module is independent and replaceable, taking into account both universality and high fidelity. It effectively solves the problem of the infeasibility of lunar surface experiments, provides a reliable means of lunar surface GNC dynamic closed-loop verification, shortens the test cycle, and significantly reduces mission risks and costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the simulation system of the present invention; Figure 2 This is a schematic diagram of the workflow of the present invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1 As shown in this embodiment, the lunar surface movement general-purpose GNC semi-physical test system based on real-time simulation is designed to simulate the real response of the lunar surface movement platform during the lunar surface movement process and to verify the effectiveness of the GNC control algorithm. It comprehensively utilizes virtual simulation, semi-physical simulation and other technical means to simulate the dynamic response of lunar surface soil, the characteristics of the unstructured environment with poor texture under strong light, the execution accuracy of actuators, the measurement error of sensors and the hysteresis of human-computer interaction with high precision, so as to realize the full-process closed-loop verification of the GNC algorithm in the dynamic scenario of the lunar surface.

[0020] The lunar surface motion general-purpose GNC semi-physical test system based on real-time simulation is designed with a modular and universal approach. It consists of three subsystems: a lunar surface dynamics simulation subsystem, which models the mobile platform, sensors, lunar terrain, and wheel-ground interaction, performs motion manipulation according to control commands, and outputs realistic motion responses such as pose; a lunar surface scene rendering subsystem, which models lunar craters, slopes, rocks, etc., renders typical lunar scenes, and outputs images and point cloud information; and a GNC control subsystem, which performs GNC closed-loop simulation based on the input motion response and image point cloud information, realizing the simulation of functions such as navigation, positioning, attitude determination, and obstacle perception, and outputs control commands through control law calculation.

[0021] The lunar surface dynamics simulation subsystem includes a lunar surface moving platform simulation module. It generates a highly realistic simulation model of the lunar surface moving platform, modeling its external parameters, mass characteristics, suspension characteristics, actuator characteristics, and tire characteristics separately. The simulation model interface is open and adjustable, allowing for rapid replacement based on actual design parameters. To realistically simulate the actuator response capability, based on actual motor selection and drive controller control algorithms, it introduces elements such as actuation rate saturation constraints, actuation delay, second-order inertial response simulation of the motor, and actuation limiting in the actuator response simulation, improving the realism of the response.

[0022] The lunar dynamics simulation subsystem includes a wheel-soil dynamics simulation module. Unlike traditional modeling methods that simplify the soil model to a hard road surface, the lunar dynamics simulation subsystem supports real-time simulation of lunar wheel-soil dynamics, models the soft characteristics of lunar soil, reflects the real tread deformation and lunar soil pressure conditions during the movement of the mobile platform, and can realistically simulate movement phenomena such as tire slippage and sinking.

[0023] The lunar surface dynamics simulation subsystem includes a sensor simulation module. Simulated sensors are generated based on the performance parameters of real sensors, and their installation positions and angles on the lunar surface moving platform simulation model are adjustable according to actual conditions. The main function of the lunar surface dynamics simulation subsystem is to model the inertial measurement unit, supporting the output of acceleration and angular velocity data.

[0024] The lunar dynamics simulation subsystem includes a terrain simulation module, which builds a three-dimensional lunar terrain model based on real lunar terrain data.

[0025] The lunar dynamics simulation subsystem includes an obstacle simulation module, which models obstacles such as rocks and simulates dynamic changes in attitude and velocity caused by the mobile platform coming into contact with obstacles by adding contact collisions.

[0026] The lunar scene rendering subsystem includes sensor simulation, terrain simulation, obstacle simulation, and lighting simulation modules. Using software such as UE, it constructs a 3D lunar terrain scene model based on real lunar terrain data, modeling lunar craters, slopes, rocks, etc. It adaptively updates lighting parameters according to changes in the solar altitude angle, simulating extreme lunar lighting and accurately and clearly reproducing the contrast between light and shadow, shadow details, and changes in lighting direction on the lunar surface. The sensor simulation module mainly involves camera and LiDAR simulation. Based on their actual installation positions and angles on the lunar moving platform, it acquires actual images and point cloud data by setting parameters such as sensor field of view, line count, and focal length.

[0027] The GNC control subsystem includes a mode selection module, an operation interaction module, a trajectory planning module, an obstacle recognition module, a navigation module, a tracking control module, an ESP module, etc. Each module is independent of the others, and more functional modules can be added according to simulation requirements.

[0028] The lunar surface motion GNC simulation system, as a general-purpose simulation system, supports GNC simulation under different operating modes, such as the commonly used ground remote operation mode, lunar surface autopilot mode, and lunar surface manned operation mode. The operation inputs for different operating modes are independent of each other. In the GNC control subsystem, the mode selection module determines the operating mode to be executed and obtains the operation intention as the control input from different interfaces according to the operating mode.

[0029] The operation interaction module converts the operator's intentions into operation commands for the lunar mobile platform through operation tools. For example, in remote operation mode, it converts the actions of ground personnel into motion control commands for the entire mobile platform, and in manned lunar operation mode, it converts the driver's joystick operation into quantifiable human driving intentions.

[0030] The obstacle recognition module uses image and point cloud information to identify objects on the lunar surface that may affect driving, such as craters, slopes, and rocks.

[0031] The trajectory planning module plans feasible trajectories in real time based on preset target points and surrounding environmental information in lunar autonomous driving mode.

[0032] The navigation module uses image, point cloud, and inertial navigation data to perform fusion navigation and positioning, determining the position, attitude, orientation, velocity, and other information of the lunar surface moving platform.

[0033] The tracking and control module tracks the desired position, speed, and heading of the mobile platform based on the trajectory planning results.

[0034] The ESP module applies stability control to the mobile platform based on its current driving status to prevent it from experiencing instability such as sideslip or brake lock-up on the soft lunar surface.

[0035] The lunar dynamics simulation subsystem and the lunar scene rendering subsystem share the same terrain file and communicate via Ethernet. The lunar dynamics simulation system outputs the position and attitude of the lunar moving platform to the lunar scene rendering subsystem, which then determines the image and point cloud data from the current viewpoint based on the position and attitude.

[0036] The lunar dynamics simulation subsystem communicates with the GNC control subsystem via a serial port (such as RS422). The lunar dynamics simulation subsystem outputs acceleration and angular velocity information measured by the inertial measurement unit to the GNC control subsystem for the navigation module to calculate. Simultaneously, it outputs information such as the position, attitude, azimuth, and velocity of the mobile platform, as well as the position and size of obstacles, to the GNC control subsystem as actual ground truth to verify the calculation accuracy of the navigation and obstacle recognition modules. The GNC control subsystem outputs control commands for driving, steering, and braking of various actuators to the lunar dynamics simulation subsystem, and the mobile platform in the lunar dynamics simulation subsystem moves and steers according to these commands.

[0037] The lunar scene rendering subsystem communicates with the GNC control subsystem via Ethernet. The lunar scene rendering subsystem outputs the images and point cloud data acquired by the mobile platform in its current pose to the GNC control subsystem for the navigation module to perform calculations.

[0038] The GNC control subsystem sends a clock synchronization signal to the lunar dynamics simulation subsystem via a serial port to ensure that the two subsystems operate in the same control cycle.

[0039] The GNC control subsystem supports access to the operating joystick via USB serial port and other methods, and converts the operator's operating intentions into operating commands for the lunar rover platform through the operation interaction module.

[0040] In addition to being generated via simulator as described above, the sensor data (including inertial measurement unit data, images, point clouds, etc.) required by the GNC control subsystem can also be communicated with the physical unit via serial port or LVDS to obtain the necessary sensor data from the unit's output port. The physical inertial measurement unit (IMU) receives acceleration and angular velocity information from the lunar dynamics simulation subsystem via serial communication and injects it into its ground measurement port. The IMU then sends the IMU measurement information back to the GNC control subsystem via serial communication for navigation and control calculations. Images and point cloud information output by the lunar scene rendering subsystem can also be converted from Ethernet to LVDS and then transmitted to the ground measurement ports of the camera and LiDAR respectively via LVDS. After receiving the ground measurement input, the camera and LiDAR send it back to the GNC control subsystem via LVDS for calculations by the navigation and obstacle recognition modules. The involvement of the physical unit introduces the measurement errors inherent in the unit itself, resulting in higher simulation accuracy.

[0041] like Figure 2 As shown, the simulation system usage method in this embodiment includes a preparation phase and a simulation phase.

[0042] The main steps in the preparation phase are as follows: Step 1: Lunar Mobility Platform Model Construction. In the lunar dynamics simulation subsystem, the external structural parameters, mass characteristics, suspension characteristics, actuator characteristics, and tire characteristics of the mobility platform are modeled separately. The simulation model interface is open and adjustable, allowing for rapid replacement based on actual design parameters.

[0043] Step 2: Terrain Model Construction. Based on the actual exploration mission location, a terrain model within the mission area is built using the real 3D terrain of the lunar surface as input. After modeling, the models are loaded into the lunar surface dynamics simulation subsystem and the lunar surface scene rendering subsystem, respectively, ensuring that the terrain files used in both are consistent.

[0044] Step 3: Construction of the lunar regolith dynamics model. A lunar regolith dynamics model is constructed within the lunar surface dynamics simulation subsystem based on real lunar regolith parameters and tire characteristics.

[0045] Step 4: Obstacle Model Construction. Construct obstacles such as rocks in the lunar surface dynamics simulation subsystem, and construct rock models of the same size at the same locations in the lunar surface scene rendering subsystem.

[0046] Step 5: Sensor Model Construction. In the lunar surface dynamics simulation subsystem, an inertial measurement unit (INS) model is constructed based on its performance parameters. In the lunar surface scene rendering subsystem, corresponding simulation models are constructed based on the camera and lidar performance parameters, respectively. The installation positions and angles of the generated simulated sensors on the lunar surface moving platform model are adjustable according to actual conditions.

[0047] Step 6: Lighting Simulation. In the lunar scene rendering subsystem, the lighting conditions are adjusted in real time based on the lunar surface light intensity, sun altitude, and other factors.

[0048] Step 7: Interface Configuration. Determine the transmission protocols such as serial port, LVDS, and Ethernet, and configure the corresponding interfaces.

[0049] The main steps in the simulation phase are as follows: Step 1: Mode Selection. The GNC control subsystem uses the mode selection module to confirm the required operating mode, such as the commonly used ground remote operation mode, lunar autopilot mode, and lunar manned operation mode. Based on the operating mode, it obtains movement input from different interfaces. For example, in ground remote operation mode and lunar manned operation mode, it reads the joystick operation signal from the serial port. In lunar autopilot mode, the target position needs to be further input.

[0050] Step 2, Operation Input. If the current mission involves operator intervention (such as ground remote operation mode or lunar surface manual driving mode), the operator can perform actions by operating the joystick. The operation interaction module in the GNC control subsystem converts the operation signal output by the joystick into actual operation commands as control input.

[0051] Step 3: Obstacle Recognition. In the obstacle recognition module of the GNC control subsystem, obstacles affecting movement, such as rocks, meteorite craters, and steep slopes, are identified based on the input image and point cloud data.

[0052] Step 4: Navigation, Positioning, and Attitude Determination. In the navigation module of the GNC control subsystem, navigation calculations are performed based on the input inertial data, image data, and point cloud data to determine the current position, attitude, orientation, and velocity of the mobile platform.

[0053] Step 5: Trajectory Planning. If the current mode is autonomous driving, the trajectory planning module of the GNC control subsystem can plan a feasible trajectory based on the obstacle recognition results.

[0054] Step 6: Trajectory Tracking. If the current mode is autonomous driving, the tracking control module of the GNC control subsystem can perform tracking control calculations on the desired position, speed, and heading of the mobile platform.

[0055] Step 7, Stabilization Control. In the GNC control subsystem, based on the motion input (such as joystick operation commands, tracking control results), stabilization control is applied to the mobile platform based on its current driving state, and control commands for the actuators are calculated.

[0056] Step 8: Clock Synchronization. The GNC control subsystem sends a clock synchronization signal to the lunar dynamics simulation subsystem via serial port to ensure that the two subsystems operate in the same control cycle.

[0057] Step 9: Lunar Motion Platform Status Update. Control commands for the actuators output from the GNC control subsystem are transmitted to the lunar dynamics simulation subsystem via serial port, driving the lunar motion platform to move according to the commands and calculating the latest driving status. The lunar dynamics simulation subsystem outputs updated acceleration and angular velocity information to the GNC control subsystem for the navigation module to calculate. The lunar dynamics simulation subsystem outputs the position and attitude of the lunar motion platform to the lunar scene rendering subsystem, which updates the image and point cloud data from the current viewpoint based on the position and attitude. In addition, the lunar dynamics simulation subsystem outputs the position, attitude, orientation, and velocity of the motion platform, as well as the position and size of obstacles, to the GNC control subsystem as actual ground truth to verify the calculation accuracy of the navigation module and obstacle recognition module.

[0058] In addition, sensor data (including inertial navigation system data, images, point clouds, etc.) can be generated by the simulator mentioned above and sent directly to the GNC control subsystem, or it can communicate with the physical unit via serial port or LVDS, and then the physical unit outputs sensor data and sends it to the control subsystem.

[0059] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0060] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A general-purpose GNC semi-physical experimental system for lunar surface movement based on real-time simulation, characterized in that, include: The lunar dynamics simulation subsystem includes models of the mobile platform, sensors, lunar topography, and wheel-to-Earth interaction. Based on the control commands sent by the GNC control subsystem, the system performs movement manipulation and outputs the movement response of the lunar surface movement platform to the GNC control subsystem and the lunar surface scene rendering subsystem. The lunar scene rendering subsystem renders the lunar scene based on the movement response of the lunar mobile platform, outputs the image and point cloud information under the current vision, and sends it to the GNC control subsystem. The GNC control subsystem performs GNC closed-loop simulation based on the lunar surface mobile platform's movement response, images, and point cloud information. This simulation enables navigation, positioning, attitude determination, and obstacle perception functions. Through control law calculation, it outputs control commands to the lunar surface dynamics simulation subsystem.

2. The system of claim 1, wherein, The lunar surface dynamics simulation subsystem includes a lunar surface moving platform simulation module, a wheel-soil dynamics simulation module, a sensor simulation module, a terrain simulation module, and an obstacle simulation module; The lunar surface moving platform simulation module models the moving platform's external parameters, mass characteristics, suspension characteristics, actuator characteristics, and tire characteristics respectively. Based on the actual motor selection and drive controller control algorithm, the actuator response simulation incorporates execution rate of change saturation constraints, actuation delay, second-order inertial response simulation of the motor, and execution amplitude limiting. The wheel-soil dynamics simulation module models the soft characteristics of lunar soil, reflects the real tread deformation and lunar soil pressure during the movement of the mobile platform, and simulates tire slippage and sinking phenomena. The sensor simulation module models the inertial measurement unit and supports the output of acceleration and angular velocity data. The terrain simulation module builds a three-dimensional terrain model of the lunar surface based on real lunar surface terrain data. The obstacle simulation module models obstacles and simulates the dynamic changes in attitude and velocity of the mobile platform after it comes into contact with an obstacle by adding contact collisions.

3. The system of claim 1, wherein, The lunar scene rendering subsystem includes a terrain simulation module, an obstacle simulation module, a lighting simulation module, and a sensor simulation module. The terrain simulation module builds a 3D lunar terrain scene model based on real lunar terrain data. The obstacle simulation module models lunar craters, slopes, and rocks. The lighting simulation module adaptively updates lighting parameters based on changes in the solar altitude angle, simulating extreme lunar lighting and reproducing the contrast between light and shadow, shadow details, and changes in lighting direction on the lunar surface. The sensor simulation module acquires actual images and point cloud data by setting sensor field of view, line count, and focal length parameters based on the actual installation positions and angles of the camera and lidar on the lunar moving platform.

4. The system of claim 1, wherein, The lunar surface dynamics simulation subsystem and the lunar surface scene rendering subsystem use the same terrain file; the lunar surface dynamics simulation subsystem and the lunar surface scene rendering subsystem exchange information via Ethernet; the lunar surface dynamics simulation subsystem and the GNC control subsystem communicate via serial port. The lunar scene rendering subsystem and the GNC control subsystem communicate via Ethernet.

5. The system of claim 1, wherein, The GNC control subsystem includes a mode selection module, an operation interaction module, a trajectory planning module, an obstacle recognition module, a navigation module, a tracking control module, and an ESP module.

6. The system of claim 5, wherein, The operation interaction module converts the operator's intentions into operation commands for the lunar mobile platform through the operation tools; in remote operation mode, it converts the control actions into motion control commands for the entire mobile platform; and in manned lunar mode, it converts the driver's joystick operation into quantifiable human driving intentions. The obstacle recognition module uses image and point cloud information to identify objects that affect driving, including lunar craters, slopes, and rocks. The trajectory planning module, in lunar autonomous driving mode, plans feasible trajectories in real time based on preset target points and surrounding environmental information, and obtains trajectory planning results. The navigation module uses image, point cloud and inertial group data to perform fusion navigation and positioning, determine the position, attitude, orientation and speed information of the lunar surface mobile platform, and obtain the current driving status of the mobile platform; The tracking control module tracks the desired position, speed, and heading of the mobile platform based on the trajectory planning results. The ESP module applies stabilization control to the mobile platform based on its current driving status to prevent instability on the soft lunar surface.

7. The system of claim 5, wherein, It also includes an inertial measurement unit, a camera, and a lidar; among which, The lunar dynamics simulation subsystem outputs acceleration and angular velocity information, which is then injected into the ground measurement port of the inertial measurement unit via serial communication. After obtaining acceleration and angular velocity information from the ground measurement port, the inertial measurement unit sends the inertial measurement information to the GNC control subsystem via serial communication. The lunar scene rendering subsystem outputs images and point cloud information, which are then converted to LVDS via Ethernet and then transmitted to the camera and LiDAR via LVDS respectively. The camera and lidar send the received images and point cloud information to the GNC control subsystem via LVDS.

8. The system of claim 7, wherein, The GNC control subsystem outputs control commands for the drive, steering, and braking of each actuator to the lunar dynamics simulation subsystem; the mobile platform in the lunar dynamics simulation subsystem moves and steers according to the control commands.

9. The system according to claim 8, characterized in that, The lunar scene rendering subsystem outputs the images and point cloud data acquired by the mobile platform in its current pose to the GNC control subsystem. The GNC control subsystem sends clock synchronization signals to the lunar dynamics simulation subsystem via a serial port; it connects to the operating joystick via a USB serial port and converts the operator's intentions into operating commands for the lunar moving platform through the operation interaction module; and it communicates with the inertial measurement unit, camera, and lidar via serial port, LVDS, and other means to acquire the necessary sensor data.

10. The control method used in the lunar surface movement general-purpose GNC semi-physical test system based on real-time simulation as described in claim 1, characterized in that, include: The GNC control subsystem selects the operating mode to be executed. Depending on the operating mode, inertial navigation data, image data, and point cloud data are acquired from external interfaces. The GNC control subsystem converts the operation signals output by the joystick into joystick operation commands. The GNC control subsystem identifies obstacles affecting movement based on image and point cloud data, and obtains obstacle identification results. The GNC control subsystem performs navigation calculations based on the input inertial data, image data, and point cloud data to determine the current driving status of the mobile platform. The GNC control subsystem plans a feasible trajectory based on the obstacle recognition results and the current driving status of the mobile platform; The desired position, speed, and heading of the mobile platform are calculated for tracking control to obtain the tracking control results; Based on the joystick operation commands and tracking control results, and considering the current driving state of the mobile platform, control commands for the actuators are calculated. The GNC control subsystem sends a clock synchronization signal to the lunar dynamics simulation subsystem via a serial port. The lunar dynamics simulation subsystem synchronizes with the GNC control subsystem based on the clock synchronization signal. The mobile platform moves according to control commands to obtain the latest driving status; The lunar dynamics simulation subsystem outputs updated acceleration and angular velocity information to the GNC control subsystem based on the latest driving status, and outputs the position and attitude of the mobile platform to the lunar scene rendering subsystem. The lunar scene rendering subsystem updates the image and point cloud data from the current viewpoint based on position and orientation; The lunar dynamics simulation subsystem outputs the position, attitude, orientation, and velocity of the mobile platform, as well as the position and size information of obstacles, to the GNC control subsystem. The GNC control subsystem verifies the accuracy of the navigation and obstacle recognition modules based on the position, attitude, orientation, speed of the mobile platform, and the position and size information of obstacles.

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