Fig. 2

Controller flowchart: the sensor input data for the control is shank angular velocity \(\dot{\theta }_{shank}\) and shank acceleration \(\ddot{x}_{shank}\) and \(\ddot{y}_{shank}\). Five main steps of data processing are required to define the motor trajectory output signal for the Walk-Run ankle. The Raw Signal Processing, the Gait Cycle Detection, the Gait Determination, the Gait Percent Determination, and the Motor Trajectory Generation. Three lookup tables from experimental gait studies of able-bodied subjects are required to run the control. One is including data similar to the sensor input as reference for determining the gait, one is including reference stride times to determine gait percent, and one is including the reference of the speed and gait dependent motor trajectories calculated in advance using the methods published in [31, 32]. If intermediate speeds are performed trajectories are interpolated