Research On Temperature Controller Of Thermal Tactile Device Based On Peltiers

The virtual reality technology has been widely used in medical treatment,aerospace and other fields.With the development of virtual reality technology,people are paying more attention to the research and application of thermal tactile.This paper focuses on this application domain of thermal tactile displays.This paper systemically expounds the basic principles of thermoelectric effects and thermoelectric cooler,and analyzes the basic theory of semiconductor refrigeration.A thermal network method based on an equivalent circuit is used for the thermal modeling.In practical application,on the one hand,there usually exist unknown disturbances in Peltier systems,including model parameter uncertainties,external disturbances,etc.In order to improve the disturbance rejection performance,the disturbance rejection technique is applied in the controller design.On the other hand,with the increase of the demand for temperature difference,single layer Peltier can not reach the larger temperature difference.Therefore,how to improve the control performance of double-layers Peltier systems is an important research issue for the larger temperature difference.On theory,major achievements include the following research:Firstly,for the stabilization problem of one-layer Peltier systems with disturbances,asymptotic composite control algorithm and finite-time composite control algorithm are designed respectively.First,in the case of with disturbance,a generalized proportional integral observer is designed to estimate the fast time-variant disturbances,and the stability analysis of the observer error system is presented.Then,for the tracking error system,based on disturbance feedforward compensation and feedback control,a asymptotic composite control algorithm and a finite-time composite control algorithm are developed respectively.The stability analysis of the closed-loop system is presented.Compared with asymptotic convergent control method,the proposed finite-time feedback control method provides a faster convergence velocity and a higher tracking accuracy.Secondly,for the stabilization problem of double-layers Peltier systems with disturbances,asymptotic composite control algorithm based on generalized proportional integral observer(DC+GPI)and finite-time composite control algorithm based on finite-time disturbance observer(FTC+FTDOB)are designed respectively.For DC+GPI,to estimate the system disturbances,a generalized proportional integral disturbance observer is constructed firstly.Then,based on the disturbance feedforward compensation and feedback control,by utilizing decentralized control theory,a composite controller(DC+GPI)is developed,which asymptotically stabilizes the disturbed system.For FTC+FTDOB,a generalized proportional integral disturbance observer is constructed firstly to estimate the system disturbances.Secondly,by compensating feedback control for disturbance estimation,a finite-time composite controller FTC+FTDOB is developed,which can stabilize the disturbed system in finite time.In experiment,major achievements include the following research:Firstly,this paper designs and builds the experimental station about thermal tactile.The device chooses OMAP-L138 produced by TI to be core controller.This chip consists of ARM9-AM1808 and DSP-C6748 and the main frequency is 456MHz.Secondly,many groups of experiments with the different situation have been finished,and verify the validity of the proposed methods.