Three Tank Water Level Control Based On Model Free Adaptive Control Theory

Level is one of the main object of modern industrial process control parameters,liquid level control in the iron and steel metallurgy, petrochemical and food processingindustry are very common. The three tanks system is a typical nonlinear and large lagobject,the traditional PID control methods are very difficult to achieve good control effectfor such complex liquid level system, it is severely restricting further of the productquality and economic efficiency; Modern control theory solved the system controllability,observability, stability and control problems of complex systems. But the modern controltheory to design the controller depend on the accurate mathematical of the object model,exacerbating the difficulty of controller design. Three-tank system is a good simulation ofa complex industrial level control objects,so this paper choose three tank water system asthe research object, study the control performance of model-free adaptive control (MFAC)for complex liquid level system, and put forward the improvement method.First the article introduced the basic theory of the model free adaptive control, andcompare the ablility of tracking, adapt, anti-lag and anti-interference between MFAC andPID by simulate on the mathematical model of three tanks system, so verifying theeffectiveness of the MFAC algorithm. Secondly, In accordance with the lag nonlineardiscrete time system, take a differential feedback compensation according to the lag time τand given the anti-lag MFAC control program; Finally, because the model-free adaptivecontrol parameter tuning is complex,according to the characteristics of the learning step ρand penalty factor λ,putting forward a parameter self-tuning model control program basedon Fuzzy and Genetic algorithms,and verify its effectiveness by Simulink simulation. Theresults show that, the model-free adaptive control algorithm adaptive to complex system isbetter than the traditional PID control algorithm; The control performance of the improvedMFAC control algorithm to lag system has been improved obviously;the parameterself-tuning control combine of genetic algorithm and fuzzy algorithm has convenientoperation, high stability and good application prospects.