Mode Variable Structure Control Research Articles

Sliding Mode Control of Grid Chaotic Oscillation based on Immune Algorithm

The bifurcation and chaos phenomenon which exist in power grid are threats to the stable operation of power grid and the safety of people and equipment. In order to eliminate the chaos phenomena in power grid, a kind of non-singular terminal sliding mode (NTSM) variable structure control method based on immune algorithm is put forward. The second-order model of grid chaotic oscillation is built and to be controlled by non-singular terminal sliding mode va riable structure controller. Meanwhile, the immune algorithm is introduced to optimize the sliding mode controller parameters. By means of simulation, the effectiveness of this method in the grid chaos control is verified.

A time-fuel optimal control problem of a cruise missile

The inadequacy of the traditional sliding mode variable structure (SMVS) control method for cruise missiles is addressed. An improved SMVS control method is developed, in which the reaching mode segment of the SMVS control is decomposed into an acceleration accessing segment, a speed keeping segment, and a deceleration buffer segment. A time-fuel optimal control problem is formulated as an optimal control problem involving a switched system with unknown switching times and subject to a continuous state inequality constraint. The new design method is developed based on a control parametrization, a time scaling transform and the constraint transcription method. A sequence of approximate optimal parameter selection problems is obtained with fixed switching time points and a canonical state inequality constraint. Each approximate optimal parameter selection problem can be solved effectively by using existing gradient-based optimization techniques. The convergence of these approximate optimal solutions to the true optimal solution is assured. Simulation results show that the proposed method is highly effective. The response speed of the missile under the control law obtained by the proposed method is improved significantly, while the elevator of the missile is constrained to operate within its permitted range. doi:10.1017/S1446181110000088

A TIME-FUEL OPTIMAL CONTROL PROBLEM OF A CRUISE MISSILE BASED ON AN IMPROVED SLIDING MODE VARIABLE STRUCTURE MODEL

AbstractThe inadequacy of the traditional sliding mode variable structure (SMVS) control method for cruise missiles is addressed. An improved SMVS control method is developed, in which the reaching mode segment of the SMVS control is decomposed into an acceleration accessing segment, a speed keeping segment, and a deceleration buffer segment. A time-fuel optimal control problem is formulated as an optimal control problem involving a switched system with unknown switching times and subject to a continuous state inequality constraint. The new design method is developed based on a control parametrization, a time scaling transform and the constraint transcription method. A sequence of approximate optimal parameter selection problems is obtained with fixed switching time points and a canonical state inequality constraint. Each approximate optimal parameter selection problem can be solved effectively by using existing gradient-based optimization techniques. The convergence of these approximate optimal solutions to the true optimal solution is assured. Simulation results show that the proposed method is highly effective. The response speed of the missile under the control law obtained by the proposed method is improved significantly, while the elevator of the missile is constrained to operate within its permitted range.

Adaptive Control of Nonlinear Uncertain Dynamical Systems

In this paper an algorithm is implemented for the control of uncertain nonlinear dynamical systems. The control algorithm is adaptive and consists of two phases. First, a system identification phase is implemented to develop a predictive model of the system based on its observed behavior. Second, a controller is designed to steer the predicted system response into a desired configuration. The control strategy to be presented in this paper is related to the well-known concepts of sliding mode control and variable structure control. Furthermore, the implementation of this control strategy utilizing smart materials is also addressed. Numerical examples are presented for the trajectory tracking and stabilization of uncertain nonlinear dynamical systems. Control strategies based on externally powered actuators and adaptive components are considered.

Sliding mode control with adaptive vss observer

The conventional sliding mode control or variable structure control (VSC) of a nonlinear uncertain system is well known for its robust property and simplicity of control law. However, the use of either is permitted only on the assumption that the upper bound of parameter variation or nonlinearity is known and that the complete information about the state is available. Although the former has recently been solved with adaptive robust control theory, the latter does not appear to be solved. This paper attempted to solve this problem using the technique of VSS adaptive robust control theory. That is, a VSS adaptive observer and a sliding mode control incorporated with this observer was proposed. The robust stability of the closed system can be proved applying Lyapunov's second method.