Study on Sliding Mode Control with Gray Theory for Electro-Hydraulic Servo System

Uncertainties in the servo system may cause the deterioration of the control quality of the electro-hydraulic servo system, and even lead to its instability. To solve this problem, this paper proposes a sliding model control (SMC) strategy with gray prediction and compensation by making use of gray prediction to identify and compensate parameter perturbation and external disturbance. Given the quality and stability of servo system will be effected by the chartering phenomenon in the SMC, this paper proposes an approach to overcome the chattering a mixed reaching law approach. The proposed control strategy improves anti-disturbance, anti-parameters perturbation capability and reduces the chattering problem. Simulation and experiment indicated that: external disturbance and parameter perturbation of the servo system can be effectively predicted and compensated by the proposed control strategy, and the problem of chattering was also inhibited obviously; the anti-interference and anti-parameters perturbation ability, stability and control quality of the system were improved.