Table 2 Symbol list of the simple-joint muscular arrangement

\(\hat{i}=1, 2, 3, 4\)

The number of the simple-joint muscle

\({\varvec{l}}_{\hat{i}}\), \({\varvec{r}}_{\hat{i}}\)

The vectors from the rotational center of the driven joint to the muscular fixed points

\(l_{\hat{i}}\), \(r_{\hat{i}}\)

The lengths of the vector \({\varvec{l}}_{\hat{i}}\) and \({\varvec{r}}_{\hat{i}}\)

\(\phi _{\hat{i}}\), \(\psi _{\hat{i}}\)

The angles between the base/link and the vectors \({\varvec{l_{\hat{i}}}}\) or \({\varvec{r_{\hat{i}}}}\)

\(\hat{\theta }_{\hat{i}}\)

The angles between \({\varvec{l}}_{\hat{i}}\) and \({\varvec{r}}_{\hat{i}}\)