Biped blind walking on changing slope with reflex control system

This paper presents a novel reflex control system for passive biped walking on unknown slope varying terrains by extension of previous work in the fields of CPG. The algorithm takes advantage of the passive dynamics of walking, assisting only when necessary with an intermittent oscillator driving the hip joint. We analyze inherent reasons of falling for a biped system based on dynamic principles and assume that human walking relies more on instinct actions within the spinal cord rather than brain. Corresponding falling tendency function is proposed, based on which a reflex controller adjusting output of oscillator is designed. An auxiliary span angle controller is put forward to provide secondary actuations for compensation to improve landing performance. The proposed reflex system requires no prior knowledge of the terrain or tens of hundreds of experiments, which are necessary for machine learning methods. Results of simulations indicate that our reflex controllers are capable of ensuring stable passive blind walking on slope varying terrains without ankle torque.