Development of 6-axis Force/Moment Sensor for Humanoid Robot Foot

Abstract

This article presents a newly designed 6-axis force/moment sensor. It is designed for humanoid robot foot to measure forces and moments during walking. The sensor uses elastic body with attached strain gages to measure force. Different from the traditional ones, the elastic body of the sensor is not integral structure but composed of two connected parts. The size of the sensor elastic body is ∅50mm × 12mm which is smaller than most of other sensors used on humanoid robot foot. With small size, it is capable of 1000N vertical force, 400N horizontal forces, 20Nm moments about the horizontal axes and 10Nm moment about the vertical axis. Cheap elastic body materials, simple structure and inexpensive strain gages make the sensor low cost. Static analysis of the sensor using FEM method and analytical method both indicated that the sensor has good sensitives, small coupling error and good structural isotropy. Dynamic analysis of the sensor under periodic ground reaction force by FEM method showed that the sensor can be used safely under humanoid robot foot. Finally, the sensor system was built and the characteristics tests were performed. The results showed that, the sensor has adequate properties for the proposed application.