Modeling and Parameters Identification for an Active Suspension System

• Main Authors: ChienCheng-Chia, 簡政嘉
• Other Authors: Shang-Chen Wu
• Format: Others
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/85946352050569097286

碩士 === 崑山科技大學 === 機械工程研究所 === 93 === ABC (Active Body Control) suspension system is used in the Mercedes- Benz vehicles. The major design of ABC suspension system links a hydraulic actuator located in the zenith of coil spring to generate a force to resist the body shock generated from the road and also maintain the body height. From the vehicle dynamic state signals receiving from each sensor, the spring coefficient and damping rations can be changed to adapt every kind of road condition and drivers’ need through the calculating and control of computers. This design increases the comfort of the riding the vehicle, decreases the body pitch and roll angle when accelerating, decelerating and turning around, and speed-dependent reduction in the body height also improves aerodynamics. By using the free-body diagram method and force balance concept, this paper has derived the car body and wheel force balance equations and state equations of the system frame for the quarter-car model of ABC suspension system. By using the flow equation and force balance concept, this paper also derives the mathematic modeling of the actuating elements of the hydraulic system including the solenoid force, orifice flow equation, the force balance equations of the armature for the 3/3 servo valve and the dynamic equation of the hydraulic cylinder. These models combined can be used to simulate and analyze the pressure variation of the suspension system and the dynamic responses and characteristics of the actuating elements. The parameters of this model will be obtained by experiments on the test rig in Vehicle Control Lab with Response Surface Methodology of Experimental Design Method and Multi-objective Optimization. The advantages of Model-Based approach are timesaving. By deriving the mathematic model, running computer simulation and validating by experiments, this Model-Based Diagnostics approach would make easy adjustments with new parameters for different suspension system.