A soft multi-axis force sensor

Thin, highly compliant sensing skins could provide valuable information for a host of grasping and locomotion tasks with minimal impact on the host system. We describe the design, fabrication and characterization of a novel soft multi-axis force sensor made of highly deformable materials. The sensor is capable of not only measuring normal force and but also 2D in-plane forces. This soft sensor is composed of an elastomer (modulus: 69 kPa) embedded with microchannels filled with conductive liquid. Depending on the intensity and the direction of an applied force, the cross-section of some of the channels will be compressed, changing its electrical resistance. The channel dimensions of the current prototype are 200 μm × 200 μm and the overall size of the sensor is 50 mm × 60 mm × 7 mm. Characterization results showed sensitivities in the two principal in-plane directions of 37.0 mV/N and -28.6 mV/N, respectively.