The Research And Realization Of Control System For Underwater Vehicle Based On CMGs

To improve the low velocity control performance of Autonomous Underwater Vehicle(AUV), a single gimbal Control Moment Gyro(CMG) is introduced as the attitude control system. The attitude control program based on Digital Signal Processing(DSP) of AUV is presented in this paper. And the problems of principle, model, feedback control algorithm, software and hardware design, experimental analysis are also researched thoroughly.The attitude control system is mainly composed by AUV, CMG, drive motor and host controller, based on TMS320F2812 DSP as a control core, the drive system consists of four brushless DC motors and four reducer motors. Introducing the torque output characteristics of CMGs and closed-loop operational principle of the AUV, and finally finish the design assignment of overall scheme.Six-degree-of-freedom dynamic equation of AUV is complicated and nonlinear, on this foundation, the state-space mathematical model can be established based on small disturbance theory. Then, from the view of modern control theory, consisting of dynamic characteristics, controllability and observability of the AUV’s attitude control system based on CMGs have been discussed. On the base of state-space mathematical modeling and dynamic analysis of the underwater vehicle, LQR optimal control theory has been used on feedback control algorithm, simulations on attitude maneuver also have been done. The matlab simulation results show that the LQR controller has satisfactory control effect and rapid dynamic response.Considering of building the hardware platform, a steady-speed control system has been presented, in which the brushless DC motors and worm gear reducer motors are based on TMS320F2812. The DSP controller module, PWM photoelectric buffer module, drive module, JTAG interface module and the RS-232 SCI module are included. Making the peripheral PCB circuit board, only employ a single DSP chip to control the starting or stopping and measure the working statement of four brushless DC motors are realized, the positive or inversion response speed of worm gear reducer motors can also be accepted.According to the scheduled hardware circuit and control strategy, the software program of this system can be designed. Based on integrated development environment CCS, the control program of starting or stopping, direction changing and speed setting can be written by C language. Functions of accepting instructions and transferring data are also realized through serial communication activities.Finally, experimental research on attitude control effectiveness of the AUV based on CMGs has been done. The experimental results indicate that the brushless DC motors can start-up in high stability and stable with expected speed, the worm gear reducer motors havethe characteristics of large output torque and rapid dynamic response. This DSP control system of CMGs has stable performance, and the obvious attitude maneuver effects of AUV illustrate that the attitude control system based on CMGs is powerful and feasible.