Development Of Attitude Control System Device Simulators For Microsatellite

The microsatellite attitude control system is used to complete the satelliteattitude and pointing control. Its test is the primary task of a microsatellite groundtest. In the closed-loop simulation test, electric simulators are used to instead of theeach single component of attitude control system generally, to simulate its functionand interface. Cooperated with other satellite devices to complete the closed-loopsimulation test, it can shorten the development period and improve the reliability ofthe microsatellite. But the existing simulators’ shape volume is large generally, theyare not portable to use, and the universality is poor. According to those kinds ofpractical requirement, a set of attitude control system device simulators formicrosatellite were designed and developed. This device realized theminiaturization and generalization, and It could complete the technical solutionspre-feasibility studies, electrical testing, fault simulation, on-orbit fault groundemersion, etc. for the microsatellite attitude control system. It was very important tothe development, testing and maintenance of the attitude control system.This thesis analyzed the requirements and techical indicators of the attitudecontrol system device simulators for microsatellite firstly, and determined theoverall plan. The device self-defined some open backplane buses, designed anddeveloped an open bus backplane with18slots, and the slots can be in common use.The self-development backplane installed in the CPCI chassis which was4U heightand has been modified. The system used rear-panel I/O boards, and realizedminiaturization. According to the simulators’ requirements, the device divided into12modules, and the digital signal modules realized generalization design. Thesimulator modules select FPGA and DSP as the core microcontroller and arithmeticunit. FPGA was used to complete the control of the modules and DSP was used tocomplete the mathematical model calculating. The device also adopted a largenumber of isolation technology, including analog isolation, digital isolation andpower supply isolation. It was good to achieve the function of satellite signalisolation and guaranteed the satety of the testing. And the design analyzed theimplementation method of the mathematical model calculating, adopted fourthorder Runge-Kutta method to complete the mathematical model calculating andused LabWindows/CVI to simulate the mathematical model, verified the result’scorrectness of the mathematical model. The communication buses of the deviceused CAN, RS-422and RS-485which were commonly used on the satellite. This design make the simulators convenient to connect with the satellite device and otherground test device, it was improve the generalization and technical inheritance ofthe system.The attitude control system device simulators for microsatellite could completethe simulation of the attitude sensors and actuators, it realized the miniaturizationand had a good compatibility and extensibility. Now, the device has beensuccessfully applied to a microsatellite ground test, cooperated with other satellitedevices to complete the closed-loop simulation test and implements50ms periodicalreal-time monitoring and testing, the attitude orientation accuracy was up to0.01°and the attitude stability was up to10-4°/s. The test results show that the device isin good agreement with design requirements. It can reduce cost, shortendevelopment period, reduce risk and improve the reliability for the development ofmicrosatellite attitude control system.