Multiobjective control synthesis based on H_∞disturbance attenuation blended with robust eigenstructure assignment is considered for a class of systems containing linear fractional uncertainties.

Disturbance Rejection for Nonlinear Time-Delay Systems Affected by Persistent Disturbances;

Consequently the problem of disturbance rejection for zero steady-state error is transformed into the optimal control problem for systems without disturbances.

In addition,Sontag s formula is used to develop the design approaches for the finite-time stable,quasi-contractively stable and disturbance rejection controllers.

We then apply the passivity theory to studies of disturbance attenuation, and put forward concise conditions guaranteeing negative output feedback to solve disturbance attenuation problems.

On the basis of Lyapunov stability theory, nonlinear robust adaptive controllers and parameter adaptive laws for speed tracking and flux tracking with unknown load torque and equivalent bounded disturbances are developed by using adaptive backstepping algorithms, nonlinear damping and disturbance attenuation techniques, and guaranteed that the system is in the s.

Tracking control and disturbance attenuation is the basic control in actual project.

Relation between Lipschitz constant and disturbance suppression ratio in H_∞ technique is analyzed by designing the state observer for Lipschitz nonlinear system, and conclusion is derived that the nonlinear system with greater Lipschitz constant generally is of poor capability of disturbance suppression.