An optimal open-loop strategy for handling a flexible beam with a robot manipulator

TL;DR

This paper introduces a simple, model-based open-loop control method for fast, vibration-free manipulation of flexible beams with robots, outperforming traditional input shaping without extra sensors.

Contribution

It presents a novel open-loop optimal control approach using a pendulum-like model that significantly reduces vibrations without additional instrumentation.

Findings

Reduces residual vibrations by at least 90%

Outperforms input shaping in speed and vibration suppression

Enables faster manipulation with minimal vibration

Abstract

Fast and safe manipulation of flexible objects with a robot manipulator necessitates measures to cope with vibrations. Existing approaches either increase the task execution time or require complex models and/or additional instrumentation to measure vibrations. This paper develops a model-based method that overcomes these limitations. It relies on a simple pendulum-like model for modeling the beam, open-loop optimal control for suppressing vibrations, and does not require any exteroceptive sensors. We experimentally show that the proposed method drastically reduces residual vibrations -- at least 90% -- and outperforms the commonly used input shaping (IS) for the same execution time. Besides, our method can also execute the task faster than IS with a minor reduction in vibration suppression performance. The proposed method facilitates the development of new solutions to a wide range of tasks that involve dynamic manipulation of flexible objects.