Study On Neural Network Predictive Control And Its Application Based On Virtual Instrument

Nonlinear phenomena widely exist in the industry process and the linearpredictive control can't qualify the control of the nonlinear system. Thepredictive control based on neural network model can control the complicatednonlinear systems whose models are unknown. So this paper studies the theoryof predictive control based on neural network (NN) model, and simulates thepredictive control based on neural network (NN) scheme taking example for thepH control of the neutralization process. Matlab, Simulink and the Sfunctionmodule in Simulink are used to design the complicated advanced controlprogram. Firstly, neural network identification models based on BP network,RBF network and wavelet network are researched. The simulation results provethat these predictive models using NN identification are efficient. Secondly, thegradient descent method is adopted to solve the optimal problem in thenonlinear predictive control and the multisteppredictive controllers aredesigned based on the wavelet net and RBF predictive models. The simulationresults show that this control algorithm has good real time characteristics. It cancontrol well by adjusting the parameters.Virtual instrument represents the development direction and fashion of theinstrument. It is significant to make use of virtual instrument to implementadvanced process control. So this paper also studies how to implement the real time advanced control in process based on the virtual instrument. After thetheories of the virtual instrument technology, the LabVIEW software and thedata acquisition are researched, the predictive control based on NN is simulatedusing the hybrid programming method with LabVIEW and Matlab, takingexample for the control process of the pH in the neutralization. In the end, avirtual instrument is designed using a DAQ board, a signal processing board,LabVIEW and a temperature control stove. Through programming anddesigning of the interface in LabVIEW, the predictive control based on NN iscarried out for the temperature control stove whose model is unknown. Theresults of the control experiment show that the controller can provide goodperformance by adjusting its parameters.