Wu Dengyun

Design of SGCMG and long life rotor bearing system technology in Tiangong-1

Single-gimbal control moment gyroscope (SGCMG) is a key attitude control actuator of Tiaqngong-1 target spacecraft. Since the successful launch of Tiangong-1 in September, 2011, the SGCMGs in it have been working smoothly in-orbit with excellent performance, which have accomplished the mission of attitude control of Tiangong-1 as well as the rendezvous docking. Now, the SGCMGs are working in the extension mission phase. In this paper, the mission requirement, design proposal, and the key technology-design of long life rotor bearing system and its test result are introduced. The SGCMGs in Tiangong-1 are developed independently by our country and utilized in-orbit for the first time. The design of long life rotor bearing system provides an important reference for SGCMGs in other spacecraft.

A low speed servo system of CMG gimbal based on adaptive sliding mode control and iterative learning compensation

In this paper, an adaptive sliding mode controller combined with iterative learning compensation strategy is proposed for the low speed servo system of control moment gyro (CMG) gimbal. The iterative learning compensation strategy is utilized to meet the requirement of speed stability, meanwhile, the adaptive sliding mode technique is used to guarantee fast response and strong robustness. This proposed method has been verified on an DSP based experimental platform, and the experimental results show that the proposed controller performs is better than conventional PID controller in speed stability, response speed and robustness.

A novel suspended method based on flux density feedback for AMB system without position sensors

A novel suspended method based on flux density feedback for AMB system without position sensors is presented in this paper. Ultra-thin Hall sensor is a part of the flux density feedback control with the function of detecting the flux density. According to the model of AMB rotor, position control-loop is realized with rotor position resolved from magnetic flux density and winding current. Flux density feedback control eliminates the model error caused by the inconsistencies between sensor target and AMB. With the novel approach, position sensors and detection target are not required; besides, size and weight of AMB system are reduced. It is of great benefit to miniaturization and integration for the space AMB system.

Research on high accuracy, long life, and high reliability technique of control moment gyroscope

The control moment gyroscope (CMG), which has the capability to produce large, continuously adjustable torques, is a key attitude control actuator for a spacecraft. The rotor spins at a constant rate about the rotor axis. Any rotation of the gimbal causes a change in the angular momentum of the spacecraft, which produces the gyroscopic moment for attitude control. On September, 2011, 200Nms CMGs were carried in orbit onboard Tiangong target spacecraft of China, which was the first inorbit application of independently developed CMG of China. 200Nms CMGs are designed for the attitude control of middle size spacecraft. Since then, even larger CMGs were under development to meet the demand of the attitude control for even larger spacecraft, such as the space station of China. In this research, three techniques are developed: System redundancy technique, for all electrical components and control electronics; Long life flywheel shafting lubrication technique, with screw cap shaped oil reservoir for 15 years long life lubrication; High stiffness gimbal drive and high accurate control technology, with harmonic reducer, and disturbance observer based terminal sliding mode control. The prototype of 1000Nms CMG was developed, and has successfully passed the qualification level environmental test.