Limiting Kinetic Energy through Control Barrier Functions: Analysis and Experimental Validation

TL;DR

This paper introduces a control method using barrier functions to limit the kinetic energy of robots, ensuring safety while minimally altering the original control commands, validated through extensive experiments on a 7-DoF robot.

Contribution

The paper presents a novel approach to enforce kinetic energy limits via control barrier functions, with a damping-based modification method that is easy to implement and robust in practice.

Findings

Effective kinetic energy limitation demonstrated on a 7-DoF robot.

Minimal invasiveness of the safety control preserves nominal control performance.

Robustness of the approach confirmed through extensive real-world experiments.

Abstract

In the context of safety-critical control, we propose and analyse the use of Control Barrier Functions (CBFs) to limit the kinetic energy of torque-controlled robots. The proposed scheme is able to modify a nominal control action in a minimally invasive manner to achieve the desired kinetic energy limit. We show how this safety condition is achieved by appropriately injecting damping in the underlying robot dynamics independently of the nominal controller structure. We present an extensive experimental validation of the approach on a 7-Degree of Freedom (DoF) Franka Emika Panda robot. The results demonstrate that this approach provides an effective, minimally invasive safety layer that is straightforward to implement and is robust in real experiments.