Fuzzy PID Electro - Hydraulic Control Steering System Analysis Of 9 - Axis All - Ground Crane

All-terrain-crane, as an necessary engineering vehicle, is widespreadly used in many large projects, and its market demand is increasing. At present, the research of kiloton-crane is still in groping in domestic. The steering system is changing from the pure mechanical mode to electronically-hydraulic control.And the handling and stability test is relatively imperfection, so the deep research on the multi-axle-steering technology is great significant.The steering system of kiloton-crane is often used mechanical mode for the front five axles and electric-hydraulic control for the rear four axles. In this paper, the electric-hydraulic proportional steering control system for the rear four axles of nine-axle all-terrain-crane was studied.Firstly, the two freedom degree model of nine-axle all-terrain-crane was established, and the dynamic characteristics on vehicle were analyzed. The relationship between speed, lateral stiffness and every axle to the steering center distance, and the relationship between angle ratio and speed were researched.Secondly, the zero-mass-center slip-angle control strategy was deduced.And the mathematical model of electric-hydraulic proportional steering actuator was established. Dynamic response characteristics of rear four axle electric-hydraulic steering system were simulated and analyzed.Finally, fuzzy PID steering system of rear four axle electric-hydraulic steering mode of nine-axle all-terrain-crane was designed. Simulation results show that the well performance of crane operation flexibility in low speed and stability in high speed can be achieved. It can give a hand for multi-axle-steering research.