Figure 3

Joint angles of a four-segment pendulum in series. (A) The base link was a floating base. Coordinated motor patterns resulted in a synchronized frequency over all the joints. In the floating-base case, traveling wave coordination could be observed. (B) The base link was fixed. Here, in-phase coordination could be observed. The learning controller found synergetic coordination while adapting to the environment, without relying on neither the model information nor the coupled oscillator. Movie S4 shows the detailed process of how the limit cycle was formed. When the environmental situation allows, neural intergrator solution was converged into simple in-phase synergetic coordination with the same amplitude as in the fixed base result. The amplitude, frequency, and phase modulation then appear in the moving base to sustain the oscillation as the total system oscillation can not be managed when the oscillation amplitude is same over the segments.