Muscle contraction leads to proportional changing in electric impedance components. This is reflected in anti-phase impedance signals behavior from antagonist muscles during wrist grasp process.
Experimentally established difference between “grasp” and “rotation” signals. Impedance signals are in-phase during wrist rotation process. This difference makes it possible to determine wrist grasp and rotation in real time.
OTWorld 2016 International Trade Show and World Congress 3 - 6 May 2016 Leipzig, Germany
Proportional neuromuscular interface for anthropomorphic bioelectric prosthesis control View presentation
The signals of the active resistance are sensitive to other movements performed by the hand, for example, bending at the elbow and leading to a false determination of the rotation. Therefore, a three-axis accelerometer needs to include into the control system to completely block the prosthesis actuators in the case of the forearm activity appearance, not related to natural rotation or grasp.