Fig. 2
From: Polymer-based flexible and multi-directional tactile sensor with multiple NiCr piezoresistors
Sensing mechanism of the proposed multi-directional tactile sensor. a Change in electrical resistance of piezoresistor with respect to applied stress. Compressive and tensile stresses cause decrease and increase in the resistance of the piezoresistor, respectively. b Operating principle for normal and shear force detections. The resistances of the four piezoresistors change identically under a normal force. In contrast, when a shear force is applied, the resistance of each piezoresistor changes differently