Hybrid passive/adaptive control of a single flexible link manipulator with a payload

In this paper, issues in the design of a hybrid passive/adaptive controller for a single flexible link robot with a payload mass are discussed. It is well known that collocated control of a single flexible link can be accomplished with PD control. It has already been shown that, with an appropriate choice of output variable (for example, the reflected tip position), a simple noncollocated "PD-like" controller, henceforth referred to as a passive controller, can provide good performance when the nominal physical parameters of the manipulator are known and do not vary significantly with time. In practical applications, a flexible link robot must be able to pick up and move unknown payloads. A fixed passive controller may not provide adequate tracking performance. In this paper, an adaptive control strategy is augmented to the passive controller introduced in to improve the tracking performance.