Development of 6-axis force/moment sensor for a humanoid robot's foot

The development of a 6-axis force/moment sensor considering adult weight for an intelligent foot of humanoid robot is described. To walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy and Fz and moments Mx, My and Mz to itself and control itself using the forces and moments. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to the foot, which is composed of Fx, Fy, Fz, Mx, My and Mz sensors in a body. Each sensor has different rated loads because the applied forces and moments to foot in walking are different. Therefore one of the important tasks in developing the sensor is to design each sensor with the different rated loads and the same rated output. A 6-axis force/moment sensor for a humanoid robot's foot was developed using parallel plate-beams. The structure of the sensor was newly modelled, and the sensing elements (plate-beams) of the sensor were designed using theoretical analysis. Then, the 6-axis force/moment sensor was fabricated by attaching strain gauges on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from the theoretical analysis agree well with that from the characteristic test.