Development Of Closed-loop Simulation Equipment For Microsatellite

Having launched a satellite into space, it will be difficult to test and maintain the satellite, thus during the course of developing the satellite, it has become the primary task to test the reliability of various subsystems of the satellite. Closedloop testing of satellites has better stable and real-time performance comparing to open-loop test, helping control of the satellite’s attitude more effectively and timely. Comparing to physical simulation and digital simulation, HILS(Hardware-in-loop simulation) has both the advantage of them, with a closer test results to the real situation but also less risk and less cost of the test. This thesis presents a universial satellite closed-loop simulation device in miniaturization to simulate the electrical interface and working timing of certain key device on the satellite. The simulator device can be used to test the attitude control subsystem at the beginning of the development of satellite, and can also simulate a variety of errors occuring in the orbit, helping find the problems in the early time of development of satellite to avoid greater loss that may come up in the future, and it is of great significance to guarantee the safety of the satellite.Firstly, the thesis describe the working and testing pri nciple taking the satellite attitude control subsystem as an example. After refining the design requirements and technical specifications of small satellite closed-loop simulation device, this thesis analyse the overall and detailed demand of each module, proposing a overall plan for the device. Power sourse computer conduct the injection of the parameter, sensor simulator complete the figure model and transfer the environmental parameters to the on-board computer, and on-board computer issues a control signal to change the operation of the actuator simulator, the actuator collecting unit collect the current status of the actuator simulator to send feedback to the power sourse computer to compare and control dynamically, and that makes a closed-loop cycle. Sensor simulator can be designed as a universial circuit board with common interface, FPGA is resiponsible for logical and timing control, DSP that support 32-bit floating calculation complete the figure model, applying FPGA reconfigure to meet different needs of the simulator. Moreover, a separate part of a CAN to wireless converter is designed to replace the traditional wired CAN bus, meeting the requirement in the future. And this thesis describes the hardware and circuit board design of every part in details, describing the firmware and software of each part including firmware of parameter injection module and program of CAN to wireless signal module.The simulator device can simulate the sensor and actuator, with a charater in universial and miniaturization. After testing, in a closed-loop simulator period, the simulator device complete the parameter injection and model figure and meet the needs of closed-loop period of 10 ms. CAN to wireless converter implement the corresponding and meet the distance of communication and working time. The equipment work firmly and meet the design and test need, saving the cost and development time also with improving the safety and reliability.