Limited Rolling Time Domain-Based Hybrid Tracking Control for Injection Molding Process

In this paper, a limited rolling time domain-based hybrid tracking control method for injection and packing-holding phase in the injection molding process is proposed. A more flexible controller is designed by adding the adjustable weighting coefficient. First, the input and output models in different phases are established based on the collected input and output data, then, the appropriate state variables are selected to establish a multi-phase state space model. In addition, then, the above model is transformed into an extended state space model containing state variables and output tracking errors, which is transformed into a switched system model. Meanwhile, the performance indicators including the terminal state are selected for different phases, and the optimal hybrid control law is obtained by combining the Riccati equation and the boundary condition. In order to find the minimum run time of each phase for different phases, the dwell time method that depends on the Lyapunov function is designed. The method is simple in design and can improve production efficiency. Finally, the feasibility and effectiveness of the proposed method are verified by modeling and simulating the injection molding process and comparing with the traditional methods.