Study On High Precise Machinery Bearing Turntable Friction Compensation

With the rapid progress of aeronautic and astronautic techniques, the performance and accuracy of inertial navigation and guidance system need to be further improved. As testing equipment of inertial navigation and guidance system, it corresponds to improve the performance and accuracy of the turntable. The angular vibration table and the servo turntable are two familiar testing devices.As we all know, the shafting friction torque is the uppermost factor that influence the high precise machinery bearing turntable control system's performance and accuracy. And the decrease of friction torque is limited by technological level and experimental funds. It just presents a new topic for holistic study manufacture level of the turntable. Therefore, designing control laws to eliminate or restrain friction influence from the viewpoint of control and thereby achieving high precision control by designing logical control algorithm are of great theoretical significance and important application value to develop a high precise machinery bearing turntable with simple structure and high performance.The thesis applies the machinery bearing angular vibration table control system and servo turntable control system as the thesis's study background, and it has a deep study on the bad influence of the shafting friction torque to the corresponding control system. Futhermore, it better improves the performance and precision of the control system by inducing the repetitive control algorithm into the friction compensation method of the system. Meanwhile, it has a computer simulation on the presented control method respectively and validates the correctness of the corresponding control method.The thesis has a basis of the deep study on friction compensation problem in angular vibration table control system, and it sets up the block diagram of the linear transfer function to control system with friction torque; furthermore, it sets up simplified dynamic equation of control system. Against abnormal variety phenomena of the wave happens when the velocity direction of system changes; furthermore, in order to reduce the THD of angular vibration table control system it presents the corresponding control method. And it supplies the guidance for using repetitive control method to settle with friction compensation problem. Against the influence of the dynamic friction torque in the angular vibration table control system, the thesis induces repetitive control algorithm into the friction compensation methods of the control system in two cases respectively. In order to reduce the THD of the system; furthermore, it presents a repetitive adaptive control method. The first case is that considering the dynamic friction torque parameters change non-uniformly. And the second case is that considering the dynamic friction torque parameters change uniformly. In each case, the convergence of friction parameters estimate and global asymptotic stability of the closed-loop system were proved via a Lyapunov-like argument.Against the influence of the friction torque with uncertainty term in the angular vibration table control system considering the uncertainty in friction model, in order to reduce the THD of the system, the thesis considers two cases. The first case is that considering the parameterize friction model's uncertainty term is unknown but constant. And the second case is that considering the parameterize friction model's uncertainty term is variable. Furthermore, it presents a modified friction control method based on decomposition control idea. In each case, the global asymptotic stability of the closed-loop system is proved via a Lyapunov-like argument.Against the low velocity creeping problem made by the friction torque in servo turntable control system, the thesis theoretically analyzes the bad influence of the friction torque to servo system; meanwhile, it supplies corresponding ameliorative measures. Furthermore, the thesis presents repetitive adaptive friction compensation control method and modified friction compensation control method based on decomposition control to analyse and study servo turntable control system respectively.