Control for a hydraulically actuated flexible-prismatic link robot

Many of the long-reach manipulators we are using for nuclear waste remediation have hydraulic actuation and flexible prismatic links. Unfortunately, most of the research related to flexible link manipulators to date focuses on single-link, fixed-length, single-plane-of-vibration test beds. In addition, many testbeds use electromagnetic drives for actuation. This manuscript describes a new test bed at Oak Ridge National Laboratory (ORNL) that has hydraulic actuation and a single flexible-prismatic link. Preliminary experiments and analysis show the effect many nonlinear characteristics have on the dynamics of commercial-grade hydraulic systems. Next, we show how these characteristics limit control design and impact flexure control strategies. Finally, a series of experiments show the performance of standard flexure control algorithms on our flexible-prismatic test bed.