Delay-dependent state-derivative feedback with an α -stability constraint for time delay systems

This paper concerns the problem of state-derivative feedback with exponential convergence rate for a linear system with a constant time-delay. This is promising for better applicability in practical systems where the state-derivative signals are easier to obtain than the state ones. Based on a system state transformation and appropriate Lyapunov functions, a sufficient condition for the design of the state-derivative feedback controller is derived in terms of delay-dependent linear matrix inequalities (LMIs). Two practical application examples are included to illustrate the effectiveness of the proposed method.