Fig 1.
(a) Rendered exploded view and (b) bottom view.
Fig 2.
Illustration of the experimental setup used in the study.
The individual in this manuscript (as outlined in the PLOS consent form) has given written informed consent to publish these case details.
Fig 3.
(a) Position of voice coil tactors, and (b) vibrotactors on the forearm during experimentation.
The figure shows the motion limiting handle and placement of one of the sEMG electrodes.
Fig 4.
Feedback schematic presented to participants.
The green, blue, and red boxes to the left of the angle marking line show the positions of the tactors on the forearm. The boxes to the right of the line show the frequency amplitude (values in Table 1) of the tactors at a given virtual wrist position.
Table 1.
Feedback control characteristics.
Fig 5.
Visual display shown to participants at the beginning of an experiment.
A similar display was shown at the end of the trial except that the Starting Position annotation and line was replaced with a Result annotation and line.
Fig 6.
(a) Box plots of participants’ mean continuous targeting errors, (b) mean discretized targeting errors, (c) success in reaching the target and (d) near success in reaching the target for the No Feedback #1 (NF1), Voice Coil (VC) Feedback, Vibrotactile (VIB) Feedback, and No Feedback #2 (NF2) cases.
The solid line in the boxes shows the median and the edges of the boxes are the 25th and 75th percentiles. The whiskers extending from the boxes show the most extreme data not considered to be outliers (within ±2.7σ) and “+” markers denote outliers.
Fig 7.
(a) Bar chart of relative targeting error for all possible step sizes (distance between initial and target positions) for the NF1, Voice Coil (VC) Feedback, Vibrotactile (VIB) Feedback, and NF2 cases.
Legend shows the step sizes in discretized units (3–9 units = 45°–120°). (b) Bar chart of targeting error based on the ending (target) position for the Voice Coil (VC) and Vibrotactile (VIB) Feedback cases. Legend shows the ending position in terms of discretized units (1–9 units = 60° to -60° virtual wrist positions).