The Simulation Modeling And Implementation Of Closed-loop Shockcontrol System Used In Pind

Particle Impact Noise Detection(PIND) test is an effective means to detect remainders, which has important significance to improve the reliability of aerospace system. Closed-loop shock control system is an important part in PIND system, it can imitate impulse excitation of the real environment to activate and dissociate particles, which are tied on the inside cavity of the test piece. Therefore, it can effectively enhance the detection capabilities of PIND system. Aiming at the issues of shock acceleration intensity keeping low level, the peak of impact wave conserving poor stability, the shock calibration having weak and slow convergence in PIND system, this dissertation conducts in-depth research of closed-loop shock control system used in PIND equipment.Firstly, the overall concept design of the closed-loop shock control system comes up. Based on the test specification of PIND, impact test conditions are proposed; based on automatic control theory, the overall scheme of the closed-loop shock control system is proposed, which includes hardware design and software design; according to characteristics of transient state and steady state, the performance index of impact of the closed-loop shock control system is proposed.Secondly, the electrodynamics shaker model is established and its parameters are identified. By analyzing the mechanical structure and working principle of electrodynamic shaker, the model of impact process is built, based on the mass-spring mechanical system, to ascertain the relationship between the peak of impact acceleration and the movement velocity of working table; based on electromagnetic theory and kinetic theory, the electrodynamics shaker model is presented, whose model parameters are estimated by the method for system identification, to ascertain the relationship between the voltage of shaker input and the acceleration of working table. According to the calculus relationship between velocity and acceleration of working table, the relationship between the voltage of shaker input and the peak of impact acceleration is established.Thirdly, the simulation model of closed-loop shock control system is established based on theory of PID control and the model parameters are optimized. According to the principles and performance indicators of PID control, a PID controller is designed; the simulation model of closed-loop shock control system is built applying Simulink tools; according to transient response characteristics of the system, the PID controller model parameters are ascertained; the feedback signal model is established to analyze the impact factors of the system deviation, find the optimal control strategy, study the relationship between the amplitude of system given input and the velocity of working table. The simulation results show that the closed-loop shock control system accurately control the velocity of working table, control error remaining within 5%.Finally, the experimental platform of closed-loop shock control system is constructed, which includes hardware and software. Aiming to completing hardware environment, the closed-loop shock circuit, acceleration acquisition circuit, main control circuit and power amplification circuit are designed; aiming to solve problems of the shock calibration having weak and slow convergence, a calibration control method based on iterative learning control algorithm is proposed. Experimental results show that the closed-loop shock control system achieves the goal of accurately controlling the change of acceleration peak value, the peak ranging from 200 g to 2500 g, the peak error kept within 5 percent, the capacity of carrying load reaching 0.1Kg; the shock calibration converges to a stable state, with the convergence times kept less than 10 times.