Design and evaluation of a three-axis force/torque sensor for humanoid robot balance control

For decades, popular culture has been enthralled with the possibility of robots that act and look like human. Walking, as one of the most important features of human, needs to be well implemented by humanoid robots. In order to perform stable robot gait, it is necessary to control the position of the Zero Moment Point (ZMP) of the robot. To calculate the ZMP, forces and moments under robot feet are important information to use. Thus, in this paper, we describe the development of a three-axis force/torque sensor to measure forces under robot feet in walking movement. The key point of this sensor is that it is very thin and light so as to not disturb the robots' gait. It also has sufficient stiffness to support heavy load. The simple structure and low cost of this sensor are also attractive points. Finite element analysis results of the sensor revealed that it is adequate to be used under robot feet.