Fig. 9

Experimental results: for visibility of learning trends, moving average with 5 window size is applied; the proposed method successfully improved the straightness of the snaking motion by optimizing the stiffness; we found the skill transfer from the FB policy to the FF policy, as can be seen in the mixture ratio as well as Fig. 5; as a remarkable point, during this transfer (10–30 episodes), the score temporarily decreased probably due to the increased frequency of use of the non-optimal FF policy