High-order Iterative Learning Fault-tolerant Control For Batch Processes With Iteration-varying Faults

Batch process can satisfy the characteristics and requirements of modern industrial processes with various superiorities such as small production,more varieties,seriation,complex synthetic steps,and intense technology.With the development of both the theory and technology,batch process plays an increasingly important role in the modern society.However,due to the high quality of the product and the complexity of the equipment,components fault happens in batch processes.Fault tolerant control for batch process has becoming one of the most important issues in the late decades.In this paper,fault tolerant control was investigated for batch processes with iteration-varying sensor faults.The batch process with sensor fault is transformed into an equivalent high-order two-dimensional model,then the high-order iterative learning control(ILC)law is designed upon the idea of feedforward-feedback ILC.The main contributions of the paper are:(1)A class of iteration-varying sensor faults described by a high-order internal model was studied.The paper shows the general methods of transforming the system model into the equivalent high-order two-dimensional Roesser model and FM model.These two high-order models make it easy to use more history information in the iteration axis,which can improve the control performance.(2)According to the high-order internal model of the sensor faults,a special high-order iteration learning fault tolerant control law was investigated.The design of a robust ILC for a batch process is transformed to a robust stabilization problem of the high-order 2D model.Then a HOIM-based iterative learning fault-tolerant control design criterion is presented to achieve the asymptotic stability.(3)The system model with iteration-varying sensor faults was transformed into an equivalent high-order 2D FM model.Similarly,a HOIM-based iterative learning fault-tolerant control law is designed.The reliable control scheme is to guarantee control performance not only when all components are operational but also in case of admissible faults.In addition,the closed loop system has good robust H? performances to unknown disturbances.(4)Application to a numerical example show that the proposed schemes can achieve the design objectives well.