Biped Robot Walking on Uneven Terrain Using Impedance Control and Terrain Recognition Algorithm

This paper proposes a control method for biped robot locomotion on uneven and uncertain terrain based on the impedance control with impedance modulation at the ankle joints and terrain recognition using force sensors at the soles. The impedance parameters are changed depending on unexpected contact forces. To reduce the size of the peak ground reaction force and to guarantee soft footing on the ground, the stiffness coefficient of the impedance of the landing foot is drastically reduced. Also, the orientation of landing foot is updated for the next phase of walking trajectory. A series of computer simulations of a 12-degree-of-freedom (DOF) biped robot with an uneven and uncertain terrain showed the effectiveness of the proposed control method.