Motion planning of a bipedal walking robot with leg-mounted ultrasonic sensors — An experimental study

This paper presents motion planning of a biped robot using leg-mounted ultrasonic sensors. An inverted pendulum model was used for modeling and simulation of kinematics. The experiments were conducted using a biped prototype. Each leg of the biped consists of four active joints; two for the hip joint, and one each for the knee and ankle joints. Overall, eight joints are controlled to execute biped locomotion. We used PID controller for damping out initial oscillations and stabilize the initial motion while starting from rest, and a PD controller for joint controls to execute motion planning. Pattern generation schemes for single & double support phases and swing phase were used for walking. In addition to stability, and balance, the primary objective is to simulate and conduct experiments to measure the performance of the biped in achieving two basic locomotions: walking and turning. Two path planning problems were attempted: (i) walking in a straight line and (ii) in a zigzag path. The error between the actual and desired path is used as a performance metric. The biped could achieve the desired motions with reasonable accuracy without tip-off or collide on the fences.