Stability and Variable Admittance Control in the Physical Interaction with a Mobile Robot

Hongbo Wang, Federico Patota, Gabriele Buondonno, Markus Haendl, Alessandro De Luca, Kazuhiro Kosuge

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Admittance controllers have been widely implemented in physical human/robot interaction (pHRI). The stability criteria and the parameter adaptation methods for admittance control have been well-studied. However, the established methods have mainly focused on human/manipulator interaction, and cannot be directly extended to mobile robot-based pHRI, in which the nonlinearity cannot be cancelled by feedback linearizations and the measurements of the relative human/robot position and orientation are usually lacking. In this paper, we study the pHRI between a human user and a mobile robot under admittance control. We develop a robotic system which can measure the relative chest/ankle positions of the human user with respect to the robot. Using the measured human position, a human frame admittance controller is proposed to remove the nonlinearity in the system dynamics. Based on the human-frame admittance control, a stability criterion is derived. By using a human arm stiffness estimator along with the derived stability criterion, a stiffness-based variable admittance controller is designed. The effectiveness of the proposed methods in improving the pHRI performance is tested and supported by simulations and experimental results.

Original languageEnglish
Article number61313
JournalInternational Journal of Advanced Robotic Systems
Issue number12
Publication statusPublished - 2015 Dec 8
Externally publishedYes


  • Admittance Control
  • Mobile Robot
  • Physical Human/Robot Interaction
  • Stiffness Estimation

ASJC Scopus subject areas

  • Software
  • Computer Science Applications
  • Artificial Intelligence


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