Nonlinear Control Techniques for Electro-Hydraulic Actuators in Robotics Engineering

초록

The general electro-hydraulic system model often includes four elements such as hydraulic cylinder, servo valve, mechatronics plant, and hydraulic parametric uncertainty. This chapter illustrates these model elements in detail. In EHS, the hydraulic cylinder is one type of motion actuator to realize the linear stretch of the plant. It often has two different styles, that is, symmetrical hydraulic cylinder and asymmetrical hydraulic cylinder. When the cylinder starts to move, the spring force and the viscous friction of hydraulic oil are two typical resistances of the electro-hydraulic system. Especially in load condition, the hydraulic pressure has to overcome the external load force to drive the plant motion. The servo valve model includes the load flow model and the spool position response model. In terms of the zero-opened four-way spool valve, the load flow of the valve can be described differently for symmetrical and asymmetrical cylinders, respectively.