Investigation of bipedal robot locomotion using pneumatic muscle actuators

Bipedal locomotion and particularly the human gait is a highly automated and complex process involving large numbers of actuators. Unfortunately actuator technology is an area of robotics with many conflicting requirements such as: high power density, high power to weight ratio, rapid response, accurate repeatable control, cleanliness, high efficiency, and low cost, which make selection complex. Pneumatic muscle actuators (PMA) based on the McKibben Muscle which can provide position and force control better than 1% have been applied to upper limbs with some success and with contractile forces in excess of 1000N (in units weighing less than 50g) there is considerable potential for use in bipedal locomotion. This paper will explore the design of a bipedal robot to take advantage of the potential of these actuators. Muscle co-ordination and control sequences will be considered for striding and standing activities and it will be shown that in terms of the energy requirements PMAs are very capable of providing a reliable bipedal drive source with linear actuation, low mass, fast response, compliant energy storage and simple construction.