An Efficient Closed-Form Method for Optimal Hybrid Force-Velocity Control

TL;DR

This paper introduces a fast, closed-form approach for hybrid force-velocity control that optimizes system conditioning, outperforming previous methods in speed and robustness, and is validated through extensive testing and manipulation experiments.

Contribution

It presents a novel closed-form method for optimal hybrid force-velocity control that is more efficient and robust than prior iterative techniques.

Findings

Method is 7 to 40 times faster than previous search-based techniques.

It consistently produces more robust solutions near kinematic singularities.

Validated on 78,000 test cases and real manipulation experiments.

Abstract

This paper derives a closed-form method for computing hybrid force-velocity control. The key idea is to maximize the kinematic conditioning of the mechanical system, which includes a robot, free objects, a rigid environment and contact constraints. The method is complete, in that it always produces an optimal/near optimal solution when a solution exists. It is efficient, since it is in closed form, avoiding the iterative search of previous work. We test the method on 78,000 randomly generated test cases. The method outperforms our previous search-based technique by being from 7 to 40 times faster, while consistently producing better solutions in the sense of robustness to kinematic singularity. We also test the method in several representative manipulation experiments.