Feedback Linearization Sliding Mode Controller Design for a High-Order Electro-Hydraulic Servo System Model

This paper presents a design of a feedback-linearization sliding-mode controller for a high-order electro-hydraulic servo (EHS) system model. The nonlinear state-space model of the EHS, including the servo valve and hydraulic cylinder, is first derived. Known nonlinearities in this model are exactly canceled via feedback linearization, yielding an equivalent linear system. A sliding surface is then designed, and a robust sliding-mode control law is derived to handle model uncertainties and external disturbances. MATLAB/Simulink simulations compare the proposed control scheme with a conventional PID controller under typical step and sinusoidal inputs. The results demonstrate that the feedback-linearized sliding-mode controller achieves faster settling and smaller steady-state error than PID control, validating its effectiveness for precision position control of electro-hydraulic servo systems.