Design Of The Torque Compensation Mechanism Based On Ultrasonic Motor

When the satellite is running in space,it will be affected by a lot of torque,and the torque will seriously affect the posture and accuracy of the satellite.So in this paper a torque compensating device is designed,the ultrasonic motor has small size,large torque,quick response,and high control precision.Therefore,this paper selects the type of the trum-60 circular travelling wave ultrasonic motor as the driving source of the device.The main contents of this paper are as follows:Firstly,the development and status of ultrasonic motor and its control technology are introduced.This paper introduces the mechanical structure of the torque compensation device,according to the form of disturbance torque,the speed tracking curve is designed.Using the method of system identifiation,the approximate model is established in the condition of specific frequency by observing and analysing the experimental data.A second-order transfer function is chosen as its equivalent mathematical model.The parameters of the mathematical model is extracted from those speed response curves which is tested in the condition of specific frequency.By comparing the actual response and simulation results the feasibility of the model is verified,it can be used for simulation.Secondly,This paper introduces the design of drive control circuit,TMS320F2812 is selected as the main control chip,push-pull circuit is used in driving circuit,and LLCC matching circuit is designed to improve the efficiency of driving circuit.Communication circuit and current protection circuit are also designed.Furthermore,software of the whole system is designed,which is divided into two parts,upper and lower,speed curvecan be drawn by using Labview.In this paper,the driver signal is generated by the method of CPLD,and the signal resolution is up to 5Hz,which fully meets the need of the control.Finally,the speed control characteristics of torque compensation device are studied on the above platform,proportional control is used to study the first step response characteristic of system,the PI control to track sine curve and the "expectations constant between zones" algorithm is proposed,then the fuzzy proportional control is used,the interpolation algorithm is adopted to improve the control accuracy.The experimental results show that the speed error can be controlled within 4r/min in the whole speed range.