A Soft, Distributed, Digital 3-axis Skin Sensor Employing a Hybrid Permanent-Adjustable Magnetic Field

In this letter, we present a new iteration of a prototype sensor module that can be used as a skin sensor for robots. The sensor uses a hybrid arrangement that consists in a small permanent magnet and an electromagnet working together above a 3-axis magnetic sensor. Both layers are separated by a flexible material that provides compliance to the sensor module. The sensitivity of the sensor can be adjusted by changing the flow of current on the electromagnet, while the permanent magnet increases the intensity of the overall magnetic field to optimize the utilization of the bandwidth of the sensor. Each sensor module includes a microcontroller with digital output that offers multimodal and distributed sensing capabilities. Problem areas of the previous version are indicated, the magnet array idea is presented and tested, and finally experiments are performed on different shapes of a flexible material to be used as middle layer.