Figure 4.

Cost function ablations

We show several ablations of our cost function and plot the average match with experimental human data, as well as the average muscle activity. A natural gait is generally characterized by a large experimental match as well as minimal muscle activity. Different ablations are shown: The adaptive effort term is zero $\left(\alpha \left(t\right)=0\right)$: no-adapt. The entire effort cost term is zero $\left(c_{\text{effort}}=0\right)$ and we deactivate the action clipping: no-effort. We only reward with the velocity reward term ($c_{\text{effort}}=0$ & $c_{\text{pain}}=0$): only-vel. Only the combined cost function achieves a close resemblance to natural gait with low muscle activity. Leaving out the pain-related costs leads to the worst gait trajectories, while a combination of the effort cost terms and the adaptive cost term is needed to achieve the lowest muscle activity. All experiments report mean $\pm$ SD over 10 random seeds.