A model of bipedal walking in unpredictably changing environment

Recent physiological studies of neural architecture of the motion control have clarified how the basal ganglia-brainstem system controls muscle tone and locomotion. The descending two major pathways from a basal ganglia-brainstem-midbrain control the activity of muscle tone and the locomotion executing system. So we have modeled an automatic control system of locomotion of a biped with these two pathways, which operates in conjunction with voluntary control processes. The locomotion executing system activates the locomotor central pattern generator, whose output alternatively generates the locomotor rhythmic patterns. Another descending pathway from a basal ganglia-brainstem-midbrain controls postural muscle tone to sustain the locomotion. We have demonstrated that the bipedal locomotion is flexibly organized by integrating the two pathways, which is more adaptable to the changes of the environment than the CPG models proposed so far.