CONTROL OF NONMINIMUM-PHASE SINGULARLY PERTURBED SYSTEMS WITH APPLICATION TO FLEXIBLE-LINK MANIPULATORS

The problem of controlling the top position of a flexible-link manipul ator is considered. A linear mathematical model of the flexible system is expressed in a standard singularly perturbed form. The concept of the integral manifold is utilized to design a dynamical composite cont rol strategy to guarantee a minimum phase closed-loop system restricte d to the manifold, resulting in controlling the tip position to an arb itrary degree of accuracy by just measuring the hub angle and the tip position. Numerical simulations for an approximation to the model of C anadarm (Shuttle arm) are included to demonstrate the advantages of th e proposed technique. The proposed control strategy is applied to both the linear and the nonlinear models of the Canadarm with very encoura ging results.