Improving backdrivability in geared rehabilitation robots |
| |
Authors: | Tobias Nef and Peter Lum |
| |
Institution: | (1) Department of Biomedical Engineering, The Catholic University of America, Washington DC, USA;(2) Center for Applied Biomechanics and Rehabilitation Research, National Rehabilitation Hospital, Washington DC, USA |
| |
Abstract: | Many rehabilitation robots use electric motors with gears. The backdrivability of geared drives is poor due to friction. While
it is common practice to use velocity measurements to compensate for kinetic friction, breakaway friction usually cannot be
compensated for without the use of an additional force sensor that directly measures the interaction force between the human
and the robot. Therefore, in robots without force sensors, subjects must overcome a large breakaway torque to initiate user-driven
movements, which are important for motor learning. In this technical note, a new methodology to compensate for both kinetic
and breakaway friction is presented. The basic strategy is to take advantage of the fact that, for rehabilitation exercises,
the direction of the desired motion is often known. By applying the new method to three implementation examples, including
drives with gear reduction ratios 100–435, the peak breakaway torque could be reduced by 60–80%. |
| |
Keywords: | Backdrivability Friction Breakaway friction Human– robot interaction Rehabilitation robotics |
本文献已被 SpringerLink 等数据库收录! |
|