A self-powered magnetoelectric 3D tactile sensor with adjustable sensitivity for robot arms

With the rapid development of robot arms in various industries, the interactions between the tip ends of robot arms and the target surfaces or objects play an important role. Tactile sensors, particularly for force measurement, are widely used at the tip ends of robot arms for information exchange. Currently, most of the tactile sensors used at the tip ends of robot arms are with one planar or arc sensing surface (2D sensing area), which can only measure the contact force when the surfaces or objects are facing the sensing surface (around 180 degrees working space range). However, contact forces may come from any direction (360 degrees working space range), which needs tactile sensors with 3D sensing area to measure multi-direction contact forces. To tackle this problem, a selfpowered magnetoelectric 3D tactile sensor (SM3D-TS) is proposed in this paper. Firstly, the design and fabrication of the SM3D-TS are described in detail. Secondly, the mechanical properties of the SM3D-TS are tested. Thirdly, the voltage-force relationship of the SM3D-TS is calibrated in single direction. Then, the force measuring and random points positioning performances are validated. Without power input, the SM3D-TS can measure contact forces from multiple directions with speed-dependent sensitivity. The experimental results show that the SM3D-TS can not only accurately measure the contact forces at given speed by independently using the induced voltages in the three axes, but also can position random points at given contact speed with high accuracy.