A three degree of freedom force/torque sensor to measure foot forces

Wearable sensors are attracting wide interests. This paper describes design of a new high strength device that is capable of support the whole weight of human or the humanoid robots when the subjects are standing or walking. This device was modeled via the application of flexure cantilever in parallel configuration to support the large force and implement the measurement. It has three degrees of freedom τ_x, τ_y and f_z which are conventionally used to validate the ground reaction force (GRF) and center of pressure (CoP) and control the humanoid robots. Furthermore, the dimension of the sensor in vertical direction is as small as 10 mm which makes it convenient to be attached to the shoes or humanoid robot foot. All these contents are contained in this paper. Firstly, the sensing principle and the structure design of this sensor are described. Next, after analyzing the structure, simulation of usual force applying cases is presented. Subsequently, acquisition system for the sensor is described. Finally, the original design of the sensor system to measure foot forces using two this sensor is mentioned.