Fig. 11
![Fig. 11](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40648-016-0046-2/MediaObjects/40648_2016_46_Fig11_HTML.gif)
Time response of the resultant forces of the experiment on the simple slope. Each leg applies normal reaction over \(R_\mathrm{{ref}}\) in the leg-grope movement as marked with the black circles. Aside from that, each normal reaction is less than \(R_\mathrm{{ref}}\). The red line, the blue line and the green line represent the \(z_{i\mathrm{S}}\), \(y_{i\mathrm{S}}\) and \(x_{i\mathrm{S}}\) elements of the resultant force with respect to \(\Sigma _{i\mathrm{S}}\), respectively. Each dotted horizontal line represents \(R_\mathrm{ref}\)