Table 1 Experimental conditions

Set-up conditions

 Weight (handle mass)

3.2 kg

 Spring constant

72.5 N/m

 \(\tilde{x}_{1d}\)

200 mm

  \(\omega _c\)

\(2\pi\)rad/s (1 HZ)

 \(\Delta \omega\)

\(\pi\)rad/s (0.5 HZ)

 Sampling time

10 ms

Experimental conditions

 Subjects

5 subjects

 Trials

5 times each pattern

 Trial time

30 s

(60 s resting interval between trials)

 Conditions

4 conditions

1 : No assist without weight

2 : No assist with weight

3 : Only power assist

\((\psi =0)\)

4 : Power assist with skill assist

\((\psi =\psi (\Delta E))\)