Concepedia

Design and Control of a Variable Stiffness Actuator for Safe and Fast Physical Human/Robot Interaction

Giovanni Tonietti, Riccardo Schiavi, Antonio Bicchi

2006 · 536 citations · 12 references

TL;DR

The paper addresses the design and control of actuators for human‑robot interaction, extending prior work on optimal mechanical‑control co‑design for intrinsically safe yet high‑performance machines, and introduces a Variable Impedance Actuation approach that jointly controls position and impedance in real time to optimize performance while guaranteeing safety. The authors aim to implement this VIA concept through a novel electromechanical Variable Stiffness Actuation motor. They describe the VSA motor’s design, dynamic behavior, and a new feedback control scheme. Experiments with a one‑link arm show that the VSA motor, under the proposed control, delivers both high performance and intrinsic safety.

Abstract

This paper is concerned with the design and control of actuators for machines and robots physically interacting with humans, implementing criteria established in our previous work [1] on optimal mechanical-control co-design for intrinsically safe, yet performant machines. In our Variable Impedance Actuation (VIA) approach, actuators control in real-time both the reference position and the mechanical impedance of the moving parts in the machine in such a way to optimize performance while intrinsically guaranteeing safety. In this paper we describe an implementation of such concepts, consisting of a novel electromechanical Variable Stiffness Actuation (VSA) motor. The design and the functioning principle of the VSA are reported, along with the analysis of its dynamic behavior. A novel scheme for feedback control of this device is presented, along with experimental results showing performance and safety of a one-link arm actuated by the VSA motor.