Evaluation of EMG, force and joystick as control interfaces for active arm supports

Evaluation of EMG, force and joystick as control interfaces for active arm supports

Lobo-Prat, J.
Keemink, A.Q.L.
Stienen, A.H.A.
Schouten, A.C.
Veltink, P.H.
Koopman, B.F.J.M.

Mechanical, Maritime and Materials Engineering

Biomechanical Engineering

2014-04-19

Background: The performance capabilities and limitations of control interfaces for the operation of active movement-assistive devices remain unclear. Selecting an optimal interface for an application requires a thorough understanding of the performance of multiple control interfaces. Methods: In this study the performance of EMG-, force- and joystick-based control interfaces were assessed in healthy volunteers with a screen-based one-dimensional position-tracking task. The participants had to track a target that was moving according to a multisine signal with a bandwidth of 3 Hz. The velocity of the cursor was proportional to the interface signal. The performance of the control interfaces were evaluated in terms of tracking error, gain margin crossover frequency, information transmission rate and effort. Results: None of the evaluated interfaces was superior in all four performance descriptors. The EMG-based interface was superior in tracking error and gain margin crossover frequency compared to the force- and the joystick-based interfaces. The force-based interface provided higher information transmission rate and lower effort than the EMG-based interface. The joystick-based interface did not present any significant difference with the force-based interface for any of the four performance descriptors. We found that significant differences in terms of tracking error and information transmission rate were present beyond 0.9 and 1.4 Hz respectively. Conclusions: Despite the fact that the EMG-based interface is far from the natural way of interacting with the environment, while the force-based interface is closer, the EMG-based interface presented very similar and for some descriptors even a better performance than the force-based interface for frequencies below 1.4 Hz. The classical joystick presented a similar performance to the force-based interface and holds the advantage of being a well established interface for the control of many assistive devices. From these findings we concluded that all the control interfaces considered in this study can be regarded as a candidate interface for the control of an active arm support.

control interface
electromyography
force
joystick
performance evaluation
learning curve
human-operator
OA-Fund TU Delft

http://resolver.tudelft.nl/uuid:d2e38b97-1a2a-492a-ab60-e8403422adf5

BioMed Central

1743-0003

Journal of NeuroEngineering and Rehabilitation, 11, 2014

Institutional Repository

journal article

© 2014 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.