A study on the zero moment point measurement for biped walking robots

The bipedal robot structure is highly suitable for working in human environments due to its advantages in obstacle avoidance and its ability to be employed as a human substitute. However, the complex dynamics involved make biped robot control a challenging task. The zero moment point (ZMP) trajectory in the robot foot support area is a significant criterion for the stability of the walk. In many studies, ZMP coordinates are computed using a model of the robot and information from the joint encoders. A more direct approach is to use measurement data from sensors mounted in the robot feet. In this paper, a foot-mounted ZMP sensor design based on force sensing resistors (FSR) is presented and experimental ZMP data obtained from the biped walking robots Mari-1 and Mari-2 and human subjects are compared in the context of reference gait generation for biped walking robots.