Observer-controller design for cranes via Lyapunov equivalence

We consider a linearized parameter-varying model of a planar crane and show how a controller can be designed, following the state-feedback stabilizati on technique for time-varying systems proposed by Wolovich. The resulting c losed-loop system is equivalent, via a Lyapunov transformation, to a stable time-invariant system of assigned eigenvalues. We also show that an observ er can be designed applying Wolovich procedure to the dual system of the pl ant. The proposed procedure leads to the computation of the desired time-va rying gains for controller and observer in a parameterized form. The result s of several simulations with data taken from a real container crane, are a lso shown. (C) 1999 Elsevier Science Ltd. All rights reserved.