Design and Implementation of a Picosat Attitude Control Subsystem

• Main Authors: Shi-Hua Wu, 吳世驊
• Other Authors: Jyh-Ching Juang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/66046428380790694598

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 94 === In Taiwan, a three-axis stabilizing CubeSat, PACE (Platform for Attitude Control Experiment), is developed and manufactured by the students and staff at NCKU. PACE is unique in the sense that it is one of the first CubeSats to employ three-axis stabilization technique. The PACE requirement is to achieve 5 degree earth pointing accuracy at 650 km altitude, 98 degree inclination of sun-synchronous orbit. The thesis presents the system design and analysis of the PACE with emphasis on the design and implementation of the attitude control and determination subsystem (ADCS). After PACE is departed from the launcher, ADCS is required to stabilize the angular rate with the B-dot control law by using a three-axis magnetometer, magnetic coils, and sun sensors. Afterward, three-axis stabilization is achieved through a momentum-biased control with the use of gyro and momentum wheel. A domestically manufactured momentum wheel mounted on Y axis of body coordinate is employed to control the pitch angle and stabilize the roll/yaw dynamics. In addition, three orthogonal magnetic coils are used to eliminate nutation and precession phenomena, and prevent the momentum wheel from saturation. To assess the effectiveness of the ADCS design, a real time hardware in the loop (HWIL) system is set up to facilitate control parameter tuning and fight software development. It can enhance the simulation accuracy by using the rapid prototyping method to simulate the space environment and satellite’s movement and control the output of actuators.