Modeling and Fuzzy PID Control of the VVVF Based Pressure Control System of Man-Made Diamond Hydraulic Force Machine

The man-made diamond hydraulic force machine using VVVF motor as pressure regulation is introduced. Through detailed analysis of its pressure control system (PCS), the PCS´ mathematical and simulation model are established. PCS is a strongly nonlinear and large time-variable system; conventional PID control can not achieve satisfactory control properties due to its bad adaptability. To handle this problem, a fuzzy PID (FPID) controller is proposed in this paper. Making full use of the human control experience acquired from practice and simulation, this FPID controller can on-line adjust the PID parameters smartly thus can achieve a better control effects. The simulation results indicate that this FPID controller has characteristics of high control precision, better dynamic and static behaviors, favorable self-adaptive capability as well as easier realization. Therefore, the proposed FPID is so adequate in practical applications that it can provide an effective ways to solve the present problem of unstable quality of the man-made diamond caused by imprecise pressure control of the synthetic machine.