A frequency-increasing wheel control system based on 20 Hz interruption

Abstract

The application discloses a frequency-increasing wheel control system based on 20Hz interruption, which comprises a main process wheel control system and a high-frequency task wheel control system; the frequency-increasing wheel control system based on 20Hz interruption can start or stop the high-frequency task mode according to actual on-orbit task requirements; if the high-frequency task mode is not started at present, only the main process wheel control system software is run, and the running frequency of the main process wheel control system software is 4hz; if the high-frequency task mode is started at present, 20hz timing interruption is started, and at this time, the high-frequency task wheel control system software is run in the form of interruption in the main process wheel control system software. Through software design, the control frequency of the control system is greatly improved, the control precision is greatly improved, the hardware cost of the control system is greatly reduced, and the hardware use efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of commercial aerospace technology, specifically to a frequency-enhanced wheel control system based on a 20Hz interruption. Background Technology

[0002] Commercial spaceflight is developing rapidly in China, presenting both opportunities and challenges, while competition is becoming increasingly fierce. To meet commercial demands, satellite platforms need to achieve high efficiency, high performance, and high reliability while maintaining miniaturization and low cost. For commercial remote sensing satellite control systems, innovative software design—which deeply explores the potential of hardware through control software, fully and efficiently utilizes the hardware system, and significantly improves the system's control performance without increasing hardware performance or cost—is particularly important.

[0003] On July 27, 2022, the world's first quantum micro-nano satellite, "Jinan-1," was successfully launched from the Jiuquan Satellite Launch Center in China. This satellite utilizes a frequency-enhanced wheel control system software design based on a 20Hz interruption. By significantly increasing the control frequency of the wheel control system during the mission, high-precision tracking of stationary ground targets was achieved. With a maximum tracking angular velocity not exceeding 0.8° / s, the control deviation of the satellite's pointing axis relative to the stationary ground target was less than 0.04°.

[0004] This software design maximizes the computing power of the satellite platform and the control performance of the attitude control system, which is of great significance for commercial remote sensing satellites with requirements for high dynamics, high precision, and high stability. Summary of the Invention

[0005] This invention provides a frequency-increased wheel control system based on a 20Hz interrupt. Through software design, the control frequency of the control system is significantly increased, the control accuracy is greatly improved, the hardware cost of the control system is reduced to the greatest extent, and the hardware utilization efficiency is maximized.

[0006] The technical solution of the present invention is: an enhanced frequency rotation control system based on a 20Hz interrupt, comprising a main process rotation control system and a high-frequency task rotation control system;

[0007] The frequency-enhanced rotation control system based on 20Hz interrupts can enable or disable the high-frequency task mode according to the actual on-orbit task requirements. If the high-frequency task mode is not currently enabled, only the main process rotation control system software runs, and the main process rotation control system software runs at a frequency of 4Hz. If the high-frequency task mode is currently enabled, a 20Hz timer interrupt is enabled, and the high-frequency task rotation control system software runs interspersed in the main process rotation control system software in the form of interrupts.

[0008] Furthermore, the specific workflow of the main process rotation system is as follows:

[0009] Step 1: Initialize the main process software;

[0010] Step 2: Read external module information;

[0011] Step 3: Remote control command processing;

[0012] Step 4: Reaction wheel processing and status determination. Is the current high-frequency task mode? If yes, read the data in the high-frequency task and start the 20Hz timer interrupt to enter the high-frequency task wheel control system. After the high-frequency task wheel control system finishes running, proceed to step 10; otherwise, proceed to step 5.

[0013] Step 5: Select the attitude control working mode;

[0014] Step Six: Control the selection of guidance law mode and the processing of guidance law;

[0015] Step 7: Select control mode and calculate control torque;

[0016] Step 8: Control instruction allocation and instruction output;

[0017] Step 9: Initialize after the high-frequency task ends;

[0018] Step 10: Write high-frequency task data;

[0019] Step 11: Process the telemetry packet and return to Step 2;

[0020] The specific workflow of the high-frequency task rotation system is as follows:

[0021] Step 1: Read the high-frequency task attitude determination and guidance law data;

[0022] Step 2: Read data from the main process control software;

[0023] Step 3: Select control mode, calculate control torque, assign control commands, and output commands;

[0024] Step 4: Write high-frequency task rotation data.

[0025] Furthermore, the specific procedures for control mode selection, control torque calculation, control command allocation, and command output in step 3 are as follows: Determine the control mode of the reaction wheel. If it is torque control, then perform the operation procedures for control torque calculation, wheel control torque allocation, and reaction wheel torque command transmission; if it is speed control, then perform the operation procedures for reading the remotely measured speed of the reaction wheel, control torque calculation, wheel control speed allocation, and reaction wheel speed command transmission.

[0026] Furthermore, the main process control system and the high-frequency task control system operate independently, and data exchange is asynchronous. They are required to read the final value of each other's data in a single loop.

[0027] Furthermore, it includes three data storage areas: a main process data storage area, a high-frequency polling control data storage area, and a data exchange storage area; the data in the main process data storage area and the high-frequency polling control data storage area are exchanged through the data exchange storage area.

[0028] The main process polling system uses only the data in the main process data storage area, and the high-frequency task polling system uses only the data in the high-frequency polling data storage area. These two data storage areas do not directly exchange data, thus achieving data isolation between the two processes. By setting up a data exchange storage area, all variables requiring data exchange can be strictly managed. By rationally arranging the execution positions of the read and write functions of the main process and the high-frequency polling process, secure and reliable data transfer can be achieved.

[0029] The beneficial effects of this invention are: through software design, the control frequency of the control system is greatly increased, the control accuracy is greatly improved, the hardware cost of the control system is reduced to the greatest extent, and the hardware utilization efficiency is improved to the greatest extent.

[0030] It highly inherits the original control system software design, realizes high-frequency operation through timed interrupt, and combines low-frequency control and high-frequency control through time-sharing operation design, which greatly improves the system development efficiency and enhances the system reliability. Attached Figure Description

[0031] Figure 1 For the software framework of the frequency-increased wheel control system;

[0032] Figure 2 Here is a basic flowchart of the wheel-controlled attitude control system;

[0033] Figure 3 Basic flowchart of the main process rotation control software;

[0034] Figure 4 This is a basic flowchart of a high-frequency task rotation control system;

[0035] Figure 5 Flowchart of data exchange between the main process and high-frequency polling interrupt;

[0036] Figure 6 This is a basic flowchart of a frequency-incremented wheel control system based on a 20Hz interrupt. Detailed Implementation

[0037] The present invention will now be further described with reference to the accompanying drawings.

[0038] The frequency-enhanced wheel control system based on a 20Hz interrupt is mainly divided into two parts, such as... Figure 6The diagram shows the main process control system software and the high-frequency task control software, respectively. The system can enable or disable the high-frequency task mode according to the actual on-orbit task requirements. If the high-frequency task mode is not currently enabled, only the main process control system software runs at a frequency of 4 Hz. If the high-frequency task mode is enabled, a 20 Hz timer interrupt is enabled, and the high-frequency task control software runs interspersed within the main process control system software as an interrupt.

[0039] The characteristics of this system can be summarized in the following four aspects in order;

[0040] Design of software framework for time-sharing frequency-increased wheel control system based on task requirements;

[0041] Detailed design of the main process rotation control system software based on the time-sharing framework;

[0042] Detailed design of high-frequency task rotation control software based on the principle of minimization;

[0043] Design of data exchange and isolation between the main process and the interrupt process.

[0044] 1. Software framework design of time-sharing frequency-increased wheel control system

[0045] To achieve the requirements of low cost and high efficiency, it is necessary to implement high-frequency control tasks solely through software without changing the existing hardware infrastructure. Since completely reconstructing the conventional low-frequency wheel control system framework would require significant time and manpower, the software framework for the frequency-enhanced wheel control system was chosen to involve limited modifications to the conventional wheel control system, adding timer interrupts to run the high-frequency task wheel control software, such as... Figure 1 As shown.

[0046] Both software programs possess complete wheel control attitude calculation capabilities. They employ a time-sharing method to schedule the two wheel control systems, enabling a significant increase in control frequency during high-precision control tasks. When a high-frequency task is not initiated, only the main wheel control software runs, while the entire high-frequency task wheel control software is stopped. When a high-frequency task begins, the modules for non-wheel control calculations and reaction wheel command transmission in the main wheel control software are run, and then the high-frequency task wheel control software is activated. At this point, the entire system retains functions other than conventional non-wheel control, such as telemetry and remote control, and stand-alone data processing. The 4Hz wheel control is stopped and replaced with 20Hz wheel control. Ultimately, this ensures that only two command frequencies are used to transmit commands to the reaction wheel: 4Hz and 20Hz.

[0047] 2. Detailed design of the main process rotation control system software based on the time-sharing framework

[0048] 2.1 Software Function Analysis During Non-High-Frequency Tasks

[0049] During non-high-frequency tasks, the main process wheel control system is similar to a conventional wheel control system. The software's control functions need to conform to the reaction wheel attitude control principle, such as... Figure 2 As shown. The guidance rate and current attitude are external inputs, provided by the attitude determination process and the mission process, respectively. The wheel control system software calculates the control deviation based on the attitude and guidance rate, and then calculates the control torque in the entire satellite coordinate system using the control algorithm and corresponding control parameters. After obtaining the control torque, the wheel control combination is selected based on the available status of the reaction wheels, thus obtaining the control commands for each flywheel. Since the availability status of the reaction wheels needs to be determined, stand-alone data processing and status judgment functions are required. In addition, it should also have functions for attitude control working mode processing, guidance mode processing, control mode processing, telemetry and remote control, etc.

[0050] Since the high-frequency task polling software is enabled based on timed interrupts, it cannot be guaranteed that the high-frequency task polling software will run after the main process polling software has finished. Therefore, regardless of whether there are high-frequency tasks, the flywheel data required by the high-frequency tasks is updated in the main program polling software. Furthermore, when the high-frequency tasks are terminated, the initial values ​​required by the high-frequency task polling software should be updated in each software cycle.

[0051] 2.2 Software Function Analysis During High-Frequency Tasks

[0052] According to the system framework, when a high-frequency task is started, since the wheel control calculations and reaction wheel command transmissions are all completed by the high-frequency task wheel control software, the main process wheel control system software needs to stop these functions, and there is no need to perform initialization operations on the high-frequency wheel control software. Furthermore, at this time, it is necessary to provide the high-frequency task wheel control software with reaction wheel status data during calculations, and also to package the calculated data in the high-frequency task wheel control software for telemetry. Therefore, a corresponding data read / write module is required at this stage.

[0053] 2.3 Detailed Design

[0054] Based on the above functional analysis, the processing flow of the main process control software is as follows: Figure 3 As shown. The main process software, which is required for both high-frequency and non-high-frequency tasks, is initialized, external module information is read, remote control commands are processed, reaction wheel processing and status checks are performed, high-frequency task data is written, and telemetry packet processing is handled outside the branch. The remaining main process flows run in the non-high-frequency task branch. In the high-frequency task, the basic wheel control attitude control flow is handled by the high-frequency task wheel control software, which only needs to read data from the high-frequency task. Wheel control commands are used for reaction wheel data processing, and other process data can be packetized and telemetry data used by the ground to confirm the software status.

[0055] As can be seen from the flowchart, the main program adds high-frequency task judgment and read / write processes to the conventional wheel control system. While meeting the requirements of short-term frequency increase, it maximizes development efficiency and saves development costs, while ensuring inheritance and reliability.

[0056] 3. Detailed Design of High-Frequency Task Rotation Control Software Based on Minimization Principle

[0057] The high-frequency mission software operates on a 20Hz cycle. Any redundant functions will significantly increase the computer load, reduce the idle time of the space mission software, and affect the reliability of the software system. Therefore, the software should be optimized as much as possible to reduce computation, retaining only the necessary data processing procedures.

[0058] Based on the basic flow of the wheel-controlled attitude control system, it can be seen that attitude data and guidance rate data, which are required for closed-loop control, need to be acquired in real time. Wheel control command calculation and output are also essential. The conventional process for determining the reaction wheel state often requires numerous logical checks to ensure reliability. Handling this in an interrupt would consume a significant amount of time. Instead, the reaction wheel state determined in the main process can be read; even in high-frequency tasks, failure to update in a timely manner will not lead to irreversible failures. Therefore, high-frequency task wheel control software must at least possess the functions of reading data from other modules in the high-frequency task, reading main process wheel control data, calculating wheel control commands, and outputting wheel control commands.

[0059] For reaction wheel control, there are two methods: flywheel torque control and speed control. When torque control is used, only the reaction wheel status data determined by the main process wheel control system needs to be read. When speed control is used, the flywheel speed also needs to be updated at 20Hz for control purposes. For example... Figure 4 As shown.

[0060] 4. Data exchange and isolation design between the main process and the interrupt process

[0061] The main process and the interrupt process run in relatively independent sequences, exchange data asynchronously, and are required to read the final value of each other's data in a single loop. Therefore, it is necessary to isolate the variables used by the two processes and then design the data exchange method based on data streams.

[0062] Data isolation between the main process and the interrupt process means that neither directly uses the other's variables, minimizing the possibility of a variable being read and used in the calculation by the other process during the intermediate calculation due to timing issues. Furthermore, data exchange between the two processes is handled by dedicated read / write functions. This ensures that variables are transmitted at the final value of a single loop, and centralized variable interaction also facilitates data management and code debugging for developers.

[0063] This system primarily uses three data storage areas: a main process data storage area, a high-frequency polling control data storage area, and a data exchange storage area. Figure 5 As shown, the main process processing function only uses data from the main process data storage area, and the high-frequency polling control processing function only uses data from the high-frequency task data storage area. These two data storage areas do not directly exchange data, thus achieving data isolation between the two processes. By setting up a data exchange storage area, all variables requiring data exchange can be strictly managed. By rationally arranging the execution positions of the read and write functions of the main process and the high-frequency polling control process, secure and reliable data transfer can be achieved.

[0064] Through software design, the control frequency and accuracy of the control system have been significantly increased, minimizing the hardware cost of the control system and maximizing hardware utilization efficiency.

[0065] It highly inherits the original control system software design, realizes high-frequency operation through timed interrupt, and combines low-frequency control and high-frequency control through time-sharing operation design, which greatly improves the system development efficiency and enhances the system reliability.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A frequency-increased wheel control system based on a 20Hz interrupt, characterized in that: This includes a main process rotation control system and a high-frequency task rotation control system; The frequency-enhanced rotation control system based on 20Hz interrupts can enable or disable the high-frequency task mode according to the actual on-orbit task requirements. If the high-frequency task mode is not currently enabled, only the main process rotation control system software runs, and the main process rotation control system software runs at a frequency of 4Hz. If the high-frequency task mode is currently enabled, the 20Hz timer interrupt is enabled, and the high-frequency task rotation control system software runs interspersed in the main process rotation control system software in the form of interrupts. The specific workflow of the main process rotation system is as follows: Step 1: Initialize the main process software; Step 2: Read external module information; Step 3: Remote control command processing; Step 4: Reaction wheel processing and status determination. Is the current high-frequency task mode? If yes, read the data in the high-frequency task and start the 20Hz timer interrupt to enter the high-frequency task wheel control system. After the high-frequency task wheel control system finishes running, proceed to step 10; otherwise, proceed to step 5. Step 5: Select the attitude control working mode; Step Six: Control the selection of guidance law mode and the processing of guidance law; Step 7: Select control mode and calculate control torque; Step 8: Control instruction allocation and instruction output; Step 9: Initialize after the high-frequency task ends; Step 10: Write high-frequency task data; Step 11: Process the telemetry packet and return to Step 2; The specific workflow of the high-frequency task rotation system is as follows: Step 1: Read the high-frequency task attitude determination and guidance law data; Step 2: Read data from the main process control software; Step 3: Select control mode, calculate control torque, assign control commands, and output commands; Step 4: Write high-frequency task rotation control data; The specific process for control mode selection, control torque calculation, control command allocation, and command output in step 3 is as follows: Determine the control mode of the reaction wheel. If it is torque control, then perform the operation process of control torque calculation, wheel control torque allocation, and reaction wheel torque command sending; if it is speed control, then perform the operation process of reading the remotely measured speed of the reaction wheel, control torque calculation, wheel control speed allocation, and reaction wheel speed command sending.

2. The frequency-increased rotation control system based on a 20Hz interrupt according to claim 1, characterized in that: The main process control system and the high-frequency task control system operate independently, and data exchange is asynchronous. They are required to read the final value of each other's data in a single loop.

3. The frequency-increased rotation control system based on a 20Hz interrupt according to claim 2, characterized in that: It includes three data storage areas: a main process data storage area, a high-frequency polling control data storage area, and a data exchange storage area; the data in the main process data storage area and the high-frequency polling control data storage area are exchanged through the data exchange storage area. The main process rotation control system uses only the data in the main process data storage area, and the high-frequency task rotation control system uses only the data in the high-frequency rotation control data storage area. The main process data storage area and the high-frequency rotation control data storage area do not directly exchange data, thereby achieving data isolation between the two processes.

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