Fig. 7

Time response of the force distributions on \(\Sigma _{i\mathrm{S}}\) of the simulation. Each leg applies normal reaction \(R_\mathrm{{ref}}\) 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 force with respect to \(\Sigma _{i\mathrm{S}}\), respectively. Each dotted horizontal line represents \(R_\mathrm{ref}\)