Research On Three-axe Micro Flywheel System For PicoSat Attitude Control

For developing PicoSAT (its mass is less than 1 kilogram), improving performance, lightening mass, decreasing size and debasing cost, three-axis micro flywheel is used for PicoSAT attitude control including normal pointing control mode and large angle attitude maneuver mode. Then a design idea of a three-axis micro flywheel system for PicoSAT attitude control is presented in this paper. In this paper, the military application of PicoSAT is introduced and the development state of micro-satellite attitude control is summarized systematically, which clarifies the important purport of research in this subject. The merit of reaction wheels control system and its component are discussed. By preferring to the related documents and Combining with the project practice, sensorless penny micromotor is used to drive micro flywheel and three-axis micro flywheel system is designed. A test system based on DSP and PC is built to test the performance of the three-axis micro flywheel system and its adaptability of working in outer space is researched, which provides a platform for further researching work in the future. To improve the precision of its control system, the math model is built in different stage of speed by preferring to the ladder response curve under different speed range. To validate the performance of attitude control of the three-axis micro flywheel system, a demo system for three-axis attitude control is made. In this system, the digital compass module HMR3000 provides heading, pitch and roll output for attitude angle, which makes attitude angle closed-loop control accomplished; the speed of flywheel is estimated by detecting the back-EMF of the penny micromotor, which makes speed closed-loop control accomplished. DSP controller is chose as the system CPU and the attitude control demo experiment is achieved by generalized the incomplete integral PID control algorithm.