Sliding Mode Control of Electro-Hydraulic Servo System Based on Optimization of Quantum Particle Swarm Algorithm

This paper investigates a sliding mode controller based on quantum particle swarm optimization algorithm (QPSO) to solve the nonlinearity of electro-hydraulic servo systems, external disturbance problems, and jitter of sliding mode controller. The electro-hydraulic servo system state space equations are established, constructing the sliding surface according to the tracking error and obtaining the output of the sliding mode controller. The ITAE metric is used as an adaptation function of the QPSO algorithm to evaluate the parameters in the sliding mode controller, which has good engineering utility and parameter selectivity. The QPSO algorithm is used to increase the randomicity of the search and to expand the search space, which can effectively prevent falling into a local optimum solution. Finally, a comparative simulation is presented to illustrate global search performance of QPSO algorithm and the effectiveness and applicability of the proposed control method.

Research on Feedback-Linearized Sliding Mode Control of Direct-Drive Volume Control Electro-Hydraulic Servo System

In this paper, a control strategy combining the feedback linearization theory and sliding mode variable structure theory is proposed to solve various nonlinear factors, uncertainty of external disturbance and high-precision pressure control problems in the Direct-Drive Volume Control (DDVC) electro-hydraulic servo system. The nonlinear mathematical model of the DDVC electro-hydraulic servo system is established, and the nonlinear factors in the system are accurately linearized by the feedback linearization theory. The uncertainty of external disturbance in the system is compensated by the sliding mode control variable structure theory. The feedback-linearized sliding mode control algorithm proposed in this paper is verified using the DDVC electro-hydraulic servo system experimental platform. The experimental results show that, compared with the classical PID control, the proposed control algorithm can effectively improve the pressure output precision, as well as the dynamic response characteristics, of the DDVC system.

Finite Time Control of a Fractional Order Hydro-Turbine Governing System With Load Rejection

This study focuses on the finite time control of a fractional order hydro-turbine governing system (HGS) with load rejection. First, the hydraulic servo system has significant historical reliance. Since it is a powerful advantage for fractional calculus to describe the function which has significant historical reliance, the fractional order hydraulic servo system is adopted and the more actual fractional order hydro-turbine governing system is presented. Second, some definitions and properties are given, and the state trajectories of HGS with load rejection is observed. The simulation results show that the state trajectory of the system is not stable, so it is necessary to design a controller with better control effect. Third, based on the frequency distribution model, the equivalent transformation model of HGS is presented. A new finite time sliding mode control scheme is proposed for the stability control of the HGS with load rejection. Furthermore, the no chattering sliding mode controller and its detailed mathematical derivation are given. The system stability is proved, and the upper limit of HGS finite time stability is given. Finally, numerical simulations have verified the theoretical results. The controller can make the state trajectories of the HGS converge to zero in a finite time, and the control time is very short.