Research On Rate Smoothness Of High Precise Turntalbes

High precision testing tables are the main testing and calibration equipments for inertial navigation systems and the instruments, and the quality performance of the high precision turn tables can directly have influence on the reliability and confidence level of the test experiments. The rate smoothness is an important performance index for turntables, which need run precisely and smoothly to satisfy the test experiments. However, the rate performances are influenced by the electromagnetic torque fluctuation and friction, so it has important theoretical and practical value to overcome the impact of these factors by control methods.Firstly, the present domestic and overseas development situation of turntables is introduced. The electromagnetic torque fluctuation and friction, which are the main two factors that influence the rate smoothness are analyzed, and the compensation methods are studied sequentiallyThe mechanism and the influence on tables of the electromagnetic torque fluctuations are analyzed deeply. A method of modified PTRC eliminating torque fluctuation is proposed which is composed with the traditional PID controllers based on the characteristic of the internal model principle that can effectively restrain the periodical disturbance. The method of optimal seletion of the repetitive control gain is proposed to improve the performance according to the pole distribution principle of control systems.According to the friction disturbance, the mechanism is analyzed. According to the Coulomb model and the LuGre model, two adaptive compensation control methods which called Model reference adaptive and self correction are proposed, that can identify the friction model parameters on-line and make a real-time compensation. Finally, the stability of the control method is proved by Lyapunov theory.According to the requirement for real time, it is known that the precision degree of RTX interruption is connected to rate characteristics of turntable. Firstly, demonstrating the point in theory that either the deviation or fluctuation would influence the rate characteristics of turntable. And then the level of influence by the deviation and fluctuation is analysed through the data of actual system.Based on researching of turntable which the laboratory has, Butterworth digital trapped filter and dither are porposed from the aspect of engineering. At last, the realization and experiment of control software based on the Windows+RTX is completed.