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Control Theory and Technology

, Volume 14, Issue 2, pp 97–112 | Cite as

Robot impedance control and passivity analysis with inner torque and velocity feedback loops

  • Michele FocchiEmail author
  • Gustavo A. Medrano-Cerda
  • Thiago Boaventura
  • Marco Frigerio
  • Claudio Semini
  • Jonas Buchli
  • Darwin G. Caldwell
Article

Abstract

Impedance control is a well-established technique to control interaction forces in robotics. However, real implementations of impedance control with an inner loop may suffer from several limitations. In particular, the viable range of stable stiffness and damping values can be strongly affected by the bandwidth of the inner control loops (e.g., a torque loop) as well as by the filtering and sampling frequency. This paper provides an extensive analysis on how these aspects influence the stability region of impedance parameters as well as the passivity of the system. This will be supported by both simulations and experimental data. Moreover, a methodology for designing joint impedance controllers based on an inner torque loop and a positive velocity feedback loop will be presented. The goal of the velocity feedback is to increase (given the constraints to preserve stability) the bandwidth of the torque loop without the need of a complex controller.

Keywords

Impedance control torque control passivity and stability analysis 

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Copyright information

© South China University of Technology, Academy of Mathematics and Systems Science, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Michele Focchi
    • 1
    Email author
  • Gustavo A. Medrano-Cerda
    • 1
  • Thiago Boaventura
    • 2
  • Marco Frigerio
    • 1
  • Claudio Semini
    • 1
  • Jonas Buchli
    • 2
  • Darwin G. Caldwell
    • 1
  1. 1.Department of Advanced RoboticsIstituto Italiano di Tecnologia (IIT)GenovaItaly
  2. 2.Agile & Dexterous Robotics Lab, ETH ZürichZürichSwitzerland

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