Development and evaluation of a compact 6-axis force/moment sensor with a serial structure for the humanoid robot foot

• A 6-axis force/moment sensor for humanoid robot foot is proposed.
• The sensor is composed of two serially connected cross-beams and strain gages.
• The developed sensor is thin, small and inexpensive.
• It has adjustable and independent sensitivities for different force components.
• The sensor has been proved to be adequate for the proposed application.

In order to walk safely, forces and moments exerted on humanoid robot foot should be measured and used for controlling the robot. This paper describes the development and evaluation of a six-axis force/moment sensor used under humanoid robot foot. The developed sensor is capable of measuring 400 N horizontal force, 1000 N vertical force, 20 N·m moment about the horizontal axis and 10 N·m moment about the vertical axis using rectangular cross-sectional beams. The structure of the sensor is newly modeled, and the sensing elements are simulated by using finite element method (FEM). Then the sensor is fabricated by attaching strain gages onto the beams. Finally, a characteristic test of the developed sensor is carried out, and the output from FEM analysis agrees with those from the characteristic test.