Magnetostrictive Tactile Sensor Array for Force and Stiffness Detection

The sense of touch, also known as tactile perception, enables enhanced ambient environment awareness for modern robots. Fe-Ga alloys have demonstrated great potential in tactile sensor applications due to their significant inverse magnetostrictive effect. This study first develops a magnetostrictive sensor unit, consisting of permanent magnets, Fe-Ga wires, and Hall sensors to detect static and dynamic forces, as well as sample stiffness. Numerical models for individual sensor units are derived for force and stiffness detection, respectively. The force measurement range of tactile sensor unit is 0 to 3 N, and the sensitivity is 126 mV/N. A tactile sensor array is then developed and validated on a commercial robotic hand. Parametric studies investigating sensor interference and sensor arrangement are completed using finite element modeling. The tactile sensor array is able to detect stiffness of both monolithic and composite samples with a measurement error less than 8.3%. The magnetostrictive tactile sensor array developed in this study can facilitate precise grasping and intelligent control for future robots.