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Table 1 Summary of the technical characteristics of the eWrist

From: Characterization and wearability evaluation of a fully portable wrist exoskeleton for unsupervised training after stroke

Performance metrics

Obtained values

Forearm module weight [g]

238

Upper arm module weight [g]

224

Myo armband weight [g]

94

Total weight [g]

556

Forearm module dimensions1 [mm]

200 ×120×802

Upper arm module dimensions1 [mm]

120 ×1603×1253

Output max. torque [Nm]

3.7

Output max. velocity [deg/s]

5304/5205

Output max. acceleration [deg/s2]

6’5104/7’5705

Force/torque range6 [N]/[Nm]

0-50/0-4

Force/torque resolution [mN]/[mNm]

7.3/0.58

Angular position resolution [deg]

0.058

Angular velocity resolution [rpm]

configurable

Restrained RoM [deg] (cf. Fig. 1d)

±77

Static friction7 [Nm]

<∣±0.1∣

Dynamic friction8 [Nm]

\(0.00198\dot {\theta }\pm 0.0135\)

Position control bandwidth [Hz]

1.74

PD steady-state error [deg]

<0.12

Autonomy9 [min]

125

Battery capacity [Wh]

11.1

  1. 1for a 1m83 tall user
  2. 2with palm support and fastening cable
  3. 3with module fingers fully extended
  4. 4in extension and in restrained RoM
  5. 5in flexion and in restrained RoM
  6. 6measurable by the load cell in both directions
  7. 7in restrained RoM
  8. 8for \(\dot {\theta }\) up to 250 deg/s, R2=0.995
  9. 9in normal use