Adaptive Impedance Control with Setpoint Force Tracking for Unknown Soft Environment Interactions

Trevor K. Stephens, Chaitanya Awasthi, Timothy M. Kowalewski

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


Robots are often required to interact with surrounding environments to complete specific tasks. In these scenarios the robot must behave in a stable manner in both free-space motion as well as constrained motion during the interaction. Additionally, for many of these cases it is important to track a setpoint force to complete a task or provide safe interaction in the absence of typically expensive force sensors. This force tracking is fairly straightforward using impedance control if the environment is known exactly a priori. However, in practice the environment is unlikely to be known and force tracking becomes inaccurate. To overcome this problem we present an adaptive impedance controller with adaptation laws for the environment parameters derived directly from Lyapunov-based stability analysis. This work focuses on interactions with soft environments which are represented using a non-linear, viscoelastic Hunt-Crossley model. After derivation and stability analysis of the controller, we present simulations of a 1 degree of freedom (DOF) robot interacting with two distinct soft environments to demonstrate the efficacy of the controller.

Original languageEnglish (US)
Title of host publication2019 IEEE 58th Conference on Decision and Control, CDC 2019
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages8
ISBN (Electronic)9781728113982
StatePublished - Dec 2019
Event58th IEEE Conference on Decision and Control, CDC 2019 - Nice, France
Duration: Dec 11 2019Dec 13 2019

Publication series

NameProceedings of the IEEE Conference on Decision and Control
ISSN (Print)0743-1546
ISSN (Electronic)2576-2370


Conference58th IEEE Conference on Decision and Control, CDC 2019

Bibliographical note

Funding Information:
This material is based upon work supported in part by the National Science Foundation Graduate Research Fellowship under Grant No. 00039202. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. (T. Stephens and C. Awasthi contributed equally to this work.) (Corresponding Author: C. Awasthi) T. Stephens, C. Awasthi, and T. Kowalewski are with the Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455 USA e-mail: (,,

Publisher Copyright:
© 2019 IEEE.


Dive into the research topics of 'Adaptive Impedance Control with Setpoint Force Tracking for Unknown Soft Environment Interactions'. Together they form a unique fingerprint.

Cite this