Research On Vibrations In Permanent Servo Driver Control System

Permanent magnet servo driver system is widely used in various industrial production application.Compliant coupling is often applied in order to improve system flexibility.Thus, position or speed vibration will occur as these flexible connection may bring lags in actual servo system. Positioning vibration affects the accurate surface quality of the work-piece.To ensure the stability of control system,it should decrease the rapidity of system response. However this is contrary with the development of high-performance and high-precise servo control system.Therefore,it is important to research the vibration suppression for servo control system.Based on the previous studies,this paper proposed different vibration suppression methods according to different frequency range.The major focus in this paper are following:The reason of vibration according to the two-mass system model is analyzed. For the low frequency(<100Hz), we adapt position error zero-crossing to detect the vibration frequency and apply a novel torque feedforward strategy to suppress the vibtation.Coefficient diagram method is used to design the control parameters.We explain how the method works based on the bode of system control.The proposed method achieved the low-frequency vibration suppression.Then,we continue analyze the mid-frequency(100-1000Hz) vibration which is brought by increasing the speed-loop gain.Improving the speed-loop gain can speed up the system response directly,but too large gain can also bring mid-frequency vibration.We discuss the relationship between the vibration frequency and system parameters and propose a low-order speed observer method to estimate vibration signal.The estimated vibration signal is used as the compensation for feedback signal.For practical vibration frequency detecting, we use FFT spectrum identification method.According to the frequency,we design the observer parameters. By this approach, we solve the mid-frequency vibration suppression problem with high speed-loop gain.When the inertia on load side is small and the elasticity coefficient is large,vib ration frequency is always high(>400Hz).Under this condition, we adopt the method of double PEAK notch filters in series connection with self-tuning ability.The self-tu nin-g approach guarantees the effectiveness of the adaptive notch filter.Additionally,a low-order lunberger disturbance torque observer is present to improve the disturbance rejection ability of servo control system.Based on the transfer function,we obtain the parameter design specification;In conclusion,we propose different vibration suppression method for different vibration frequency range. The design of parameter is discussed in detail since it is important in practical application. At last,we use the simulation and experiments to proof the effectiveness of proposed methods.