Analysis And Improvement Of Turntable For Low Rate Performance

With the development of aerospace and aviation, higher requirements forsimulation turntables are raised while the low-rate performance is becoming thebottleneck for improving the turntable’s performance. There are many factors affectingthe low-rate performance of turntable servo system, analyzing these factors and puttingforward methods to improve has important theoretical significance and engineeringapplication value.In the paper, the servo system is firstly described, and the object model isdetermined after mechanism modeling, then the model parameters are identified withthe frequency domain response data. Based on these steps, the factors that block theimprovement of turntable servo system low-rate performance are analyzed and theinfluence of friction torque, ripple torque and measurement noise are discussed.Then proceeding from the most important factor that has an impact on theturntable’s low-rate performance, the common dynamic friction model is given. Withthe help of LuGre friction model, the adverse effects on the system are deducedtheoretically, and it is pointed out that friction will result in the delay of the starting time,undermine the stability of the system and cause the "stick-slip" phenomenon in the lowrate.Lastly, the low-rate performance is improved with the high-gain observer, andseparation law is applied to design the controller and observer. It is shown in theanalysis that the high-gain observer can restrain the friction torque, ripple torque, andsome constraining factors when designing high-gain observer are discussed. Onextension of high-gain observer, the system disturbance torque can be obtained so as torealize friction compensation. It is verified that expanding high-gain observer canestimate the disturbance quickly which has a good compensation effect and effectivelyimprove the low-rate performance of the system.