Design And Analysis Of A Safe Six-Axis Force Sensor For Humanoid Robots

While the humanoid robot is walking, the force information between robot and external environment can be detected by the six-axis force sensor which is installed in the feet of robot. However, the problem of force coupling usually appears in existing technology during the measurement. This will decrease dynamic response characteristics and the measurement accuracy of the sensor directly. In addition, there are problems of insufficient bearing capacity and no safety protection. Considering the bearing capacity, structure rigidity and safety protection, this paper designed the structure of sensor's mechanical body, signal processing system and the scheme of calibration according to a kind of six-axis force sensor device for humanoid robot.The structure of sensor's mechanical body was designed. Three elastic beams and two cylindrical force-delivering poles were combined together in a special touching mode: point-touching mode and line-touching mode, which enabled that the deformation of the three beams did not affect each other and the three component forces independent from each other. Force coupling was eliminated directly from structure principle. The function of overload protection was obtained by setting safety block.Then the bearing capacity of sensor was increased by using reasonable beam material.According to the differences among the force modes of each beam when forcing, this paper ensured the pasting scheme of resistance strain gage and the force detection principle of sensor, and established the expressions between the output voltage of strain bridge and the force of beam.The signal processing system of six-axis force sensor was designed. This paper used DSP as main processor, and the peripheral circuit had the functions of signal amplifying, signal filtering and AD converting. The usage of RS-232 standard serial interface implemented the communication between sensor and computer.The manufacture of sensor's mechanical body and circuit board were finished. In addition, the calibration force scheme of sensor's beams was designed, which provided hardware foundation for the next development and experiment of sensor.