Design and validation of a novel friction electro-hydraulic loading system

The conventional electro-hydraulic load simulator is subjected to motion disturbance of the tested equipment. To eliminate the disturbance, a novel friction electro-hydraulic loading system for testing actuators or servo drive systems is proposed to improve the accuracy of load simulation in the laboratory environment. The motion disturbance of the test equipment on conventional electro-hydraulic load simulator is analyzed. And an active electro hydraulic torque servo loading system based on friction loading is designed. According to the principle of loading, the mathematical model of the friction loading system is established. It shows that the friction loading scheme is not affected by motion of tested equipment. In view of the fact that there are many variable parameters in the actual process, especially time-varying and uncertain friction, simulations are made to analyze the loading performance of the friction electro-hydraulic loading system. Simulation results show that the conventional electro-hydraulic load simulator may be disturbed by motion of the tested equipment so greatly that Its loading performance is hard to be further promoted. Although the friction coefficient may be influenced by the relative motion, load pressure, temperature and other factors. the friction electro-hydraulic loading system can keep high precision torque simulation.