Study And Realization On Key Technology For Improve Velocity Stability

The stability of velocity is one of key indexes of servo system, e.g. opti-cal-electrical tracking system, test turntable call for high level of this index. Espe-cially when the servo system working in the low velocity, servo system face to the problems such as limitation of resolution and kinds of disturbance of transmission. So, the rate of velocity stability degrades. This paper mainly focus to improve the stability of velocity. The context and main conclusion are in the below:The mathematical model is established based on the dynamic characteristic. Mechanism analysis and experiment result are used to establish mathematical model of disturbance.The source of low velocity estimation errors and the shortcomings of the single period difference were analyzed. The state observer and Kalman filter are proposed to estimate the velocity. These methods are based on the dynamic and kinematics char-acteristic of servo system. Experiment results show that, when the input is 1°/s, these methods reduce the estimation error nearly 30%. With the method of Newton predic-tor, the conflict between bandwidth and phase lag are solved.The pattern of how friction and force ripple influence the stability of velocity is analyzed. Friction may cause the servo system has steady state error. when the servo system run near Stribeck velocity, the friction may induce limit cycle. Because the friction influences the stability of closed loop system. Force ripple may cause the ve-locity of servo system has some cycle fluctuation. The adaptive robust control strategy is used to design the compensation to the disturbance. As to the force ripple, the RLS method is used to identify the certain parameters of disturbance. The compensation part is calculated based on the parameter and math model. As to the friction, beside compensate friction on line, the sliding model control is used to improve the robust-ness to some unmodeled dynamic and fluctuation of parameter.At last, from the aspect of engineering application, some methods are verified in turntable. These methods include: the improved lead-lag with the integrator, the lead-lag control with acceleration and integrator, the adaptive robust control with force ripple compensation. Compared to lead-lag method which velocity fluctuation is 2.92%(RMS), the first method reduce to 0.9%, the second method reduce to 0.47%, the third method reduce to 0.39%.