Design and Characterization of Large-Range 3-D Force Tactile Sensor Based on Fe-Ga Alloy

Tactile sensors are among the essential components for human–robot interaction in robotics. The force applied to the robot hand is coupled with both normal force (in the ${z}$ -direction) and shear force (in the ${x}$ - and ${y}$ -directions). Additionally, the robot hand must withstand significant force while grasping the object. As a result, it is crucial to develop a sensor that can measure a wide range of 3-D forces. This article proposes a tactile sensor for 3-D force based on Fe-Ga alloy and hyperelastic material polydimethylsiloxane (PDMS). The output voltage model of the Fe-Ga alloy sensing unit has been established. The tunneling magnetoresistance sensor outputs a voltage signal that reflects changes in the magnetic field. We established a 3-D force simulation test platform to examine the static and dynamic characteristics of the sensor. The experimental results indicate that the sensing unit’s sensitivity is 310.15 mV/N between 0- and 5-N range, and the experimental output voltage matches the calculated value. The sensor measured the normal force between 0- and 25-N range with a sensitivity of 56.53 mV/N and the shear force between 0- and 12.5-N range with a sensitivity of 50.82 mV/N. The sensor’s response time and recovery time, which are less than the human skin response time, are 40 and 42 ms, respectively. The proposed sensor has potential applications in the fields of electronic skin, intelligent robotics, and prosthetics due to its high sensitivity and large force measurement range, which is based on the inverse magnetostrictive effect.