Robust Task-Priority Impedance Control for Vehicle-Manipulator Systems

Abstract

Enabling vehicle-manipulator systems to perform complex and precise intervention operations requires a robust control framework capable of handling redundancy and interaction forces. In addition, it is desirable that the method allows completion of several tasks with a strict prioritization to keep safety critical tasks unaffected by other goals. In this paper, a control method is developed for a broad class of vehicle-manipulator systems, with the main use case being floating base underwater vehicle manipulator systems subject to hydrodynamic forces. In underwater applications, large model uncertainties will be present due to hydrodynamic and hydrostatic effects, unknown disturbances and modelling errors. This means that a viable solution must be robust to disturbances and modelling errors, while also satisfying strict task priorities and compliant contact behaviour. To achieve this, a robust impedance based task-priority control method is presented, and its stability and robustness properties are proven. The method is validated in a simulation of an articulated intervention autonomous underwater vehicle (AIAUV).