Pattern recognition of myoelectric signals in
upper-limb prosthesis control has been subject to intense
research for several years. However, few systems have yet
been successfully clinically implemented. One possible explanation
for this discrepancy is that published reports mostly
focus on classification accuracy of myoelectric signals recorded
under laboratory conditions as the metric for the system’s
performance. These data are usually acquired only during the
static state of the contraction in a fixed seated position. This
supports the test subject in performing repeatable contractions
throughout the experiment and generally results in an unrealistically
high classification accuracy. In clinical testing however,
subjects have to perform various activities of daily living,
causing the limb to move in different positions. These variations
in limb positions can significantly decrease robustness and
usability of myoelectric control systems. Recent reports have
shown that the so-called limb position effect can be resolved
for the static state of the signal by adding accelerometer
data to the feature vector. Including data from the transient
state of the signals for classifier training generally significantly
increases the classification error so it is mostly not considered in
published reports. In this paper, we investigate the classification
accuracy of transient EMG data, taking into account the limb
position effect. We demonstrate that a classifier trained with
features from EMG, accelerometer and gyroscope outperforms
classifiers using only EMG or EMG and accelerometer data
when classifying transient EMG data.