| Establishing the mathematical model of electro-hydraulic servo system is the key to analyze and design control system and base of studying control means in effect. The modeling methods currently used are appropriate for linear systems based on block graph. The methods could neither describe the inherent non-linearity of electro-hydraulic servo system veraciously nor describe the system's power flow. The appearance of power bond graph affords powerful technical measure for establishing the model of hydraulic system veraciously, and provides possibility for analyzing hydraulic system's dynamic performance exactly.Based on numerous related literatures and reference materials at home and abroad, the thesis makes electro-hydraulic servo synchronization control system the research object, establishes the system's model and simulates with the method power bond graph. It studies the extraneous force in synchronization control system and synchronization control strategy according to structure invariance principle. Simulating and real results both indicate that the control strategy could effectively compensate the extraneous force from synchronization movement.According to the working characteristics of electro-hydraulic servo synchronization control system and considering the nonlinear factors on the servo valve, leakage of the cylinder and friction, the system's power bond graph is founded. Then the synchronization position and force load system's analysis in time-domain and frequency-domain is achieved. The thesis deeply analyzes the principle that extraneous force comes into being, studies its trait, and validates it by simulation in bond graph.Based on theoretic analysis and simulation calculation, the thesis according to structure invariance principle constructs flow compensation controller which adopts the velocity-estimate methods. At the same time synchronization control system's power bond graph based on flow compensation is founded. Then simulation research is accomplished. The results prove that the methods flow compensation could effectively compensate the extraneous force from synchronization movement. The experiment results also validate the conclusion. |
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