Research On The Nonlinear Tempreture System With The Variable Structure Control Theory

Temperature control is very general no matter in the experimental system or in the project is employed.And the regulator is very important part in the control system.In order to obtain better speed control result,research on the control algorithm must be carried out.So,after analyzing,designing the electronic governor with the sliding variable structure control algorithm is presented and corresponding work has been done.According to course and operation principle of temperature control of course-control-experimental-provision,and silicon controlled rectifier,and hot flow produced,fit the linear relation between regulating valve degree and hot flow under the environment of MATLAB.According to the principle of,set up the whole pair of non-linear models which holds the control system of temperature.On the basis of non-linear model,resolve temperature systematic mathematical model into one two-order linear system and one single input nonlinear system.For single input nonlinear differential equation,the non-linear differential equation of speed control system is converted into a high-order differential equation,one imitative non-linear system,linear brief type and discrete-time system form separately.Firstly,the equal control and sliding mode movement equation are obtained.Secondly,to get sliding mode variable structural controller,a suitable convergence law is selected. Regard the whole nonlinear model of temperature system as one mul-input to research including two kinds of methods that nonlinear state varying and looks variable form.At last,get the sliding mode variable structural controller.Based on the non-linear model,MATLAB simulation of the non-linear approximate model is carried out.Finally,the simulation results of the sliding mode variable structural controller are analyzed.The question shaking appeared is analyzed. The conclusions are as follows:1.The non-linear model of the temperature system is correct;2.The control result of the sliding mode variable structural control algorithm to a non-linear system is good;3.It shows that the sliding mode variable structure control is able to respond quickly,robust against system parameters and external disturbances,and able to keep the system stable,obtain strong robustness.But shaking is a problem.On the basis of MATLAB Simulation,regarding DSP artificial device as the hardware,carry on the sliding mode variable structure control prototype code download of control system,which offered the basis for development of the products.Carrying on experiments of course control,analyze result of the solve coupling control experiment which utilizing traditional PID algorithm.Utilizing KINGVIEW software platform and C language software designing,carry on the sliding mode variable structure control of the water temperature.Comparing speed data gathered for the sliding mode variable structure control algorithm with data gathered for PID,it can be found out that for the sliding mode variable structure control, the steady state error is small and overshoot is smaller.But shaking exists.