Sliding Mode Control with Time-Varying Switching Hyperplane for Data Transmission Networks

Discrete time sliding mode control systems ensure a high degree of robustness with respect to disturbance by confining the system state to a specified vicinity of the switching hyperplane. However, quickly driving the state towards that vicinity often results in unfeasibly large values of the control signal. In order to ensure that robust quasi-sliding motion of the system begins immediately at the start of the control process while limiting the magnitude of the control signal and state variables, a new time-varying sliding hyperplane is proposed. An additional state variable not present in the original system is specified and the hyperplane is defined in the extended state space. The effect of this new variable on quasi-sliding motion of the system diminishes over time and eventually reaches zero. The strategy which drives the system representative point onto the time-varying hyperplane is applied to control the flow of data in connection-oriented communication networks. For such plants, it is demonstrated that the proposed approach allows one to impose bounds on the input and output of the system at all stages of the control process.