A new nonlinear sliding mode controller is presented for a second-order nonlinear dynamic system with mismatch parameter uncertainty and external disturbance. Firstly, this paper proposes a new nonlinear sliding mode with an arctan function on which the system states are stable asymptotically. Secondly, a nonlinear silding mode controller is developed to guarantee that the system states can reach the sliding mode surface from any initial system state in finite time and stay the domain of the equilibrium point. Finally, an illustrative example shows that the controller is robust to parameter uncertainty and eliminate external disturbance caused by chattering nearby the sliding mode surface. Also, consume energy of this method is the least than that of the linear sliding mode controller and terminal sliding mode controller.

A new nonlinear sliding mode control system design

With respect to a kind of missile with deflectable nose, six-degree-of-freedom dynamics mathematical model including deflectable nose dynamic was established using momentum principle, and guidance system model was presented, at the same time the whole attitude control system with deflectable nose was designed based on variable structure control theory. In order to prove the correctness of the validity of the altitude control strategy, under the environment of MATLAB6.5/SIMULINK, the six-degree-of-freedom digital simulation system was studied and developed for missile with deflectable nose. Finally simulation about non-maneuverable target and the snake-shape maneuverable target were conducted; the results validate the strong maneuverability and intercepting capability of the supersonic missile with deflectable nose, and show the designed control method was effective to the attitude control system.

Modeling and simulation research of missile with deflectable nose

Variable structure control of general multivariable nonlinear systems and its implementation by use of observers are studied in this paper. The necessary condition and sufficient condition for the existence of sliding modes arc given. It is shown that the states of the controlled systems will approach asymptotically the sliding sub-space (or submanifold)globally (or locally, respectively) for linear systems (or a class of nonlinear systems, respectively) if the variable structure control laws arc implemented with state observers.

Gao Weibing

Papers

On Variable Structure Control of Nonlinear Systems and Its Implementation