State dependent control of a robotic manipulator used for nuclear decommissioning activities

Abstract

This article considers pole assignment control of nonlinear dynamic systems described by State Dependent Parameter (SDP) models, with a particular focus on a Brokk 40 mobile robot and Hydro-Lek HLK-7W two-arm manipulator used for nuclear decommissioning tasks. The UK nuclear legacy comprises a number of facilities that are significantly contaminated by radioactivity and non-radiological toxins. Here, the use of remote and teleoperated robotic solutions provide an invaluable option for the safe retrieval and disposal of contaminated materials. Since the behaviour of hydraulically-driven manipulators is dominated by the nonlinear, lightly-damped dynamics of the actuators, existing systems can suffer from a relatively slow and imprecise control action. For this reason, the research utilises a non-minimal state variable feedback approach to control system design, in which the control gains are updated at each sampling instant.