A Multiaxis Force Sensor Based on Pre-Strained Piezoresistive Film Strips

Soft multi-axis force sensors are essential in automation and robotic manipulations for dexterous applications. Carbon-based composites are quality candidates for sensing elements of soft multi-axis force sensors due to its piezoresistivity originated from electron tunneling effect. However, low cost and fast-prototyped soft multi-axis force sensors based on tunneling effect of carbon-based composites are still in their infant. This work investigated a soft multi-axis forces sensor utilizing Velostat film strips as the core sensing elements. A unique serpentine structure of Velostat strips has been designed and implemented as piezoresistors for the soft force sensor. The sensitivity of the proposed multi-axis force sensor has been characterized in x, y and z directions. Experimental results show that the sensor can achieve 2.1%/N and 2.2%/N in x and y axis, and 4.2%/N in z axis, respectively. The force sensor has been implemented in dexterous manipulations with a robotic gripper as the proof-of-concept, which demonstrates great potential for multi-axis force sensing applications.