Research On Electro-Hydraulic Automatic Level Control System Of Automible Body Of Aerial Work Platform

The main objective of this dissertation is to develop a valve-controlled cylinder electro-hydraulic positioning closed-loop control system with four-channel actuators through automatic control principle study,theoretical modeling, simulated analysis and experiment practice about leveling system. Taking Hangzhou Aichi engineering vehicle Co.Ltd SN15B series aerial work platform as background, mono-direction supporting level-strategy will be applied to electro-hydraulic automatic control system for platform of automobile body; the valved-controlled cylinder electro-hydraulic position closed-loop control system has features of a higher precision and automatic level acting on the automobile body of aerial work platform.Firstly, according to the actual require of leveling device,an electro-hydraulic automatic control system has be finished; a sequence of actions for level and vertical legs designed; the stability of parking on hill demonstrated;the automobile body of aerial work platform manually leveled.Secondly, proceed from optimal computation of drive parameters for valve-controlled cylinder, a method of hydraulic power system has been used to match the electro-hydraulic leveling system and select the key components.Then, electro-hydraulic proportional valve-controlled cylinder system mathematical model is built according to classical transfer function based on electro-hydraulic proportional control theory, which starts from hydro-dynamics flow equation, continuity equation and force equilibrium equation. In virtue of Matlab software, the system is proven to be stable using frequently analysis. Besides, electro-hydraulic closed-loop control is built under the condition of Simulink, which makes it dynamic simulation and analysis come true.Finally, performance test platform of automobile body of aerial work vehicle is designed and built for functional test and experimental study.Test results show that mono-direction supporting level-strategy is feasible for the level system of automobile body of aerial work platform, in which the leveling precision is within the range of0.3degrees,the leveling time is less than one minute, and it maintains a stable state more than8hours, which lays a solid foundation for the four-point electro-hydraulic automatic level control.