Fig. 4
From: Comparison of vibrotactile and joint-torque feedback in a myoelectric upper-limb prosthesis
a Signal flow diagram of prosthesis control. Terms are described in Eqs. (1) and (2). b Signal flow diagram of haptic feedback. Terms are described in Eqs. (3) and (4). The matching function block refers to Eq. (4). c Sample time-series showing the terminal device aperture percent closed (PC), the normalized net EMG signal (Snet), the load cell signal (L), the exoskeleton output torque (T), the exoskeleton elbow angle (θE), and the vibrotactile skin displacement (V) for the hard (solid-blue), medium (red-dot), and soft (yellow-dash) blocks. Traces are truncated to a window after the initial start of object grasp to highlight the rate-limited ramp-up period of the feedback. Note that feedback is only turned on when PC ≥100 (Et, denoted by grey horizontal dashed line. Grey vertical dashed line identifies the time-point when Et is reached)