Research On Fuzzy Adaptive Control Of Time-delay Molding System With Multiple Constraints

Molding technology is one of the core technologies of the manufacturing industry,and it has been widely used in the fields of precision molds,robotics and chemical industries.However,the molding system is a typical nonlinear system with constraints and delays.Its molding effect is affected by many factors.For example,the delay will reduce the stability of the system.If the state is not constrained,the system may be out of control.Control problems caused by nonlinear factors,the impact of external disturbances on system performance,and how to accurately model the mechanism of the system.Therefore,it is of great significance to study the adaptive control algorithm corresponding to the phase-forming system.Since the molding system is a typical unknown nonlinear system with constraints and time delays,this thesis uses the backstepping method and fuzzy logic system as the basis to solve the control problem of the unknown nonlinear system.The barrier Lyapunov function is used to realize the state constraint,and the Lyapunov-Krasovskii function is used to compensate the time delay problem.Finally,the control algorithm is designed by combining it.The validity of the algorithm is demonstrated by the experimental verification of the time-delay forming system with multiple constraints.The main contents of this paper are as follows:(1)For the mechanism modeling of the cooling molding system,the corresponding mathematical model is designed based on the laws of physics,and a certain reasonable simplification is carried out to obtain the state equation of the forming system.In addition,simulation experiments are carried out on the obtained mathematical model to analyze the influence of various parameters on the system.(2)For the tracking control problem of the cooling molding system with full state constraints and time delays,this thesis adopts the backstepping method and fuzzy logic system as the basis of the control algorithm.The adaptive control algorithm is designed according to the theoretical basis of the stability of the system.Secondly,for the system state constraint problem,the tan-type potential barrier Lyapunov function is used to realize the state constraint of the whole system.Finally,an exponential LyapunovKrasovskii function is used to compensate for the effects of time delay,and these are combined to form a fuzzy adaptive control method for time-delay nonlinear systems with full state constraints.(3)For the tracking control problem of the cooling molding system with asymmetric time-varying constraints and delays,the tan-barrier Lyapunov function is improved,and an asymmetric time-varying tan-barrier Lyapunov function is designed to constrain the system state;The dynamic surface control method of the first-order sliding mode differentiator is used to improve the backstepping method to obtain more control performance.It is combined to form a fuzzy adaptive dynamic surface control method for time-delay nonlinear systems with asymmetric time-varying full-state constraints.To sum up,according to the characteristic that the molding system is a typical nonlinear system with constraints and time delays,a corresponding control algorithm is designed to realize the tracking control,and the validity of the algorithm is finally verified by experiments.