A Class Method And Experimental Study CMG Framework System

As Control Moment Gyroscope system has many notable advantages such as big output torque, fast response, low power consumption and so forth, it has been more and more widely used in attitude control system of spacecraft. Now, control of gimbal system of Control Moment Gyroscope with character of multi-variable, nonlinearities and coupling are still difficult to deal with. In this paper, a class of Control Moment Gyroscope with multi degree of freedom, nonlinearities, coupling are studied with the ECP Model750Control Moment Gyroscope experiment system. Several problems such as uncertain factor, coupling and friction which come up in the control of practical system are analyzed and the corresponding solving approaches are followed. The main contents of this paper are concluded as follows.1) According to the kinematics and dynamics mechanism, a full-order nonlinear mathematical model of the ECP Model750Control Moment Gyroscope system are built. Besides, by linearization around the operating point, the linearized model with three different configurations and control modes including reaction torque control, gyroscopic torque control and reaction and gyroscopic torque control are obtained respectively.2) Based linear model, PD controller is designed under reaction control mode; pole placement controller and robust H∞state feedback controller with pole restriction is designed under gyroscopic torque control mode, results of simulation and experiment demonstrate the robust H∞state feedback controller has better disturbance rejection capacity and robust performance with parameter perturbations; for reaction and gyroscopic torque control, firstly two controllers against each single variable system in different mode is simultaneously acted. For the problem of coupling, MIMO full state feedback LQR controller is designed, results of simulation and experiment demonstrate the controller has reduced the coupling and has better dynamic performance and tracking ability.3) Based on nonlinear model, input-output decoupling linearization method is adopted and a fuzzy PID intelligent controller is designed. For the problem that the friction effects in practical system can’t be eliminated, a LuGre friction model for the Control Moment Gyroscope system is built on the base of genetic algorithm and then the friction effects can be compensated to some satisfied extent, results of simulation and experiment verifies the effectiveness of the method. Furthermore, aimed at improving the tracking performance, based on Caplygin model of nonholonomic systems, backstepping tracking controller and tracking trajectory is designed for multi-axis tracking control, the simulation results show that it has good stability and dynamic tracking performance, which verifies the effectiveness of the tracking controller.