Stable Contact Guaranteeing Motion/Force Control for an Aerial Manipulator on an Arbitrarily Tilted Surface

TL;DR

This paper presents a novel motion/force controller for aerial manipulators that guarantees stable contact and accurate tracking on arbitrarily tilted surfaces, validated through experiments with different approach speeds and orientations.

Contribution

It introduces a Kelvin-Voigt model-based force estimation and a disturbance-observer controller designed for stability during contact transitions.

Findings

Successful tracking of time-varying motion/force trajectories.

Stable contact maintained on arbitrarily tilted surfaces.

Effective handling of model uncertainties and switching conditions.

Abstract

This study aims to design a motion/force controller for an aerial manipulator which guarantees the tracking of time-varying motion/force trajectories as well as the stability during the transition between free and contact motions. To this end, we model the force exerted on the end-effector as the Kelvin-Voigt linear model and estimate its parameters by recursive least-squares estimator. Then, the gains of the disturbance-observer (DOB)-based motion/force controller are calculated based on the stability conditions considering both the model uncertainties in the dynamic equation and switching between the free and contact motions. To validate the proposed controller, we conducted the time-varying motion/force tracking experiments with different approach speeds and orientations of the surface. The results show that our controller enables the aerial manipulator to track the time-varying motion/force trajectories.