An event-controlled online trajectory generator based on the human-robot interaction force processing
Abstract
Purpose
The problem of robotic co-manipulation is often addressed using impedance control based methods where the authors seek to establish a mathematical relation between the velocity of the human-robot interaction point and the force applied by the human operator (HO) at this point. This paper aims to address the problem of co-manipulation for handling tasks seen as a constrained optimal control problem.
Design/methodology/approach
The proposed point of view relies on the implementation of a specific online trajectory generator (OTG) associated with a kinematic feedback loop. This OTG is designed so as to translate the HO intentions to ideal trajectories that the robot must follow. It works as an automaton with two states of motion whose transitions are controlled by comparing the magnitude of the force to an adjustable threshold, in order to enable the operator to keep authority over the robot's states of motion.
Findings
To ensure the smoothness of the interaction, the authors propose to generate a velocity profile collinear to the force applied at the interaction point. The feedback control loop is then used to satisfy the requirements of stability and of trajectory tracking to guarantee assistance and operator security. The overall strategy is applied to the penducobot problem.
Originality/value
The approach stands out for the nature of the problem to be tackled (heavy load handling tasks) and for its vision on the co-manipulation. It is based on the implementation of two main ingredients. The first one lies in the online generation of an appropriate trajectory of the interaction point located at the end-effector and describing the HO intention. The other consists in the design of a control structure allowing a good tracking of the generated trajectory.
Keywords
Acknowledgements
Erratum - It has been brought to the attention of Emerald Group Publishing that the article “An event-controlled online trajectory generator based on the human-robot interaction force processing”, published in Industrial Robot, Volume 41, Issue 1, contained a number of errors introduced in the submission and production process.
These included the following:
The authors' affiliations should have been listed as ‘Univ Paris-Sud, Orsay, France and CNRS and SUPELEC, LSS, UMR8506, Gif-sur-Yvette, France’.
The following acknowledgement should have been included:
This work is supported by CNRS, Région I^le-de-France and DIGITEO via grant #2009-042D “ROBOTEO HANDLING”. Sarra Jlassi also received a scholarship from the Islamic Development Bank for science and technology.
The corresponding author's email address should have been: Sami Tliba, sami.tliba@lss.supelec.fr
Additionally, a number of figures were placed in the wrong order and labelled incorrectly.
Emerald, its typesetters and the authors apologise to the readers for any inconvenience caused. The online version of the article has been corrected.
This work is supported by CNRS, Région I^le-de-France and DIGITEO via grant #2009-042D “ROBOTEO HANDLING”. Sarra Jlassi also received a scholarship from the Islamic Development Bank for science and technology.
Citation
Jlassi, S., Tliba, S. and Chitour, Y. (2014), "An event-controlled online trajectory generator based on the human-robot interaction force processing", Industrial Robot, Vol. 41 No. 1, pp. 15-25. https://doi.org/10.1108/IR-01-2013-317
Publisher
:Emerald Group Publishing Limited
Copyright © 2014, Emerald Group Publishing Limited