Fig. 5: Comparison between animal and robot gait selection policy strategies during increasing linear velocity.

a, The bottom two plots of all robot data indicate the percentage of each gait utilized at that velocity. Magenta, purple and blue shaded regions indicate the transition phases of \({\pi }_{{\mathrm{G}}}^{{\rm{uni}}}\), \({\pi }_{{\mathrm{G}}}^{{W}_{{\rm{ext}}}}\) and animals, respectively. This study compares transition strategies of \({\pi }_{{\mathrm{G}}}^{{\rm{uni}}}\) and \({\pi }_{{\mathrm{G}}}^{{\rm{CoT}}}\) with data collected from dogs³⁵ and horses^33,46 in terms of CoT (top left), \({\pi }_{{\mathrm{G}}}^{{\rm{uni}}}\) and \({\pi }_{{\mathrm{G}}}^{{\tau }_{ \% }}\) with data collected from horses³⁷ in terms of foot ground reaction forces (top right), \({\pi }_{{\mathrm{G}}}^{{\rm{uni}}}\) and \({\pi }_{{\mathrm{G}}}^{{W}_{{\rm{ext}}}}\) with horses³³ in terms of external work (bottom left), and \({\pi }_{{\mathrm{G}}}^{{\rm{uni}}}\) and \({\pi }_{{\mathrm{G}}}^{{c}^{{\rm{err}}}}\) with opossums and dogs³⁵ (bottom right). b, Mapping the correlation between metrics and the average gait ID selected across velocities for terrains \({h}_{{\rm{terr}}}^{0}\) and \({h}_{{\rm{terr}}}^{3}\), with the dataset of each terrain consisting of 31 data points averaged over 1,000 samples.