Interactive Force-Impedance Control

TL;DR

This paper introduces a unified Interactive Force-Impedance Control framework that guarantees passivity and safety during contact-rich human-robot interactions, enabling stable collaboration and reducing impact forces.

Contribution

It presents a novel port-Hamiltonian based control architecture that ensures passivity and stability in hybrid force-impedance control scenarios with humans.

Findings

Ensures stable collaboration in contact-rich environments.

Reduces contact impact forces and force oscillations.

Guarantees autonomous system passivity during interaction.

Abstract

Human collaboration with robots requires flexible role adaptation, enabling the robot to switch between an active leader and a passive follower. Effective role switching depends on accurately estimating human intentions, which is typically achieved through external force analysis, nominal robot dynamics, or data-driven approaches. However, these methods are primarily effective in contact-sparse environments. When robots under hybrid or unified force-impedance control physically interact with active humans or non-passive environments, the robotic system may lose passivity and thus compromise safety. To address this challenge, this paper proposes a unified Interactive Force-Impedance Control (IFIC) framework that adapts to interaction power flow, ensuring safe and effortless interaction in contact-rich environments. The proposed control architecture is formulated within a port-Hamiltonian framework, incorporating both interaction and task control ports, thereby guaranteeing autonomous system passivity. Experiments in both rigid and soft contact scenarios demonstrate that IFIC ensures stable collaboration under active human interaction, reduces contact impact forces and interaction force oscillations.