Practical techniques for optimal dual-rate digital redesign

This paper proposes optimal dual-rate digital redesign methods that can be applied to continuous-time and fast-rate discrete-time control systems. Given a continuous-time control system, or a fast discrete-time control system, the paper presents techniques relying on the solution of a dual-rate H/sub 2/ discrete-time control problem to convert such systems to either a slow-rate or a dual-rate sampled-data control system while guaranteeing closed-loop stability and performance in the discrete-time H/sub 2/ sense. The proposed techniques result in sampled-data control systems having satisfactory performances over an extended range of sampling rates, when compared with other widely used methods of digital redesign. Furthermore, the proposed digital redesign techniques are useful in practice since they allow the designer to constrain the complexity of the digital controllers. Numerical examples demonstrate the performance of the proposed digital redesign techniques and provide a comparison with well-known approaches.