Flexible Hair Tactile Array Based on Micro Magnetic Particles

Tactile sensing is an essential modality for humans to perceive the external environment. With the increasing popularity of household robots, precise grasping and safe human-machine interaction have become increasingly important. A crucial way to solve these problems is to endow robots with large-area tactile perception capabilities. In recent years, tactile sensors based on various principles have been developed. Among them, tactile sensors based on magnetic principles have the advantages of high resolution, low mechanical hysteresis, and non-contact measurement. In addition to film and convex structures, tactile sensors with hair structures have also been developed, which can greatly increase device sensitivity[1-2]. However, these studies often use a single hair or a small amount of hairs to achieve single-point measurement[3]. Therefore, it is difficult to apply them in robot skin or other fields requiring large-area perception, and it is also difficult to achieve complex functions. 

In this paper, we propose a magnetic hair array with tactile sensing ability. Every hair in the array contains a large number of micro magnetic particles. When the external force acts on the hair array, multiple hairs will bend under the force. At this time, the size and direction of the stray magnetic field under the hair array will change. The magnitude and direction of the external force can be calculated by detecting this change through the magnetic sensor array under the hair array. The magnetic hair array is then applied to sliding tactile sensing and object recognition. It can realize precise detection of the size, direction, and sliding of external force and achieves a success rate of 97% in object recognition. In addition to recognizing the shape of objects, the magnetic hair array can identify whether the object has magnetism inside, which has great application potential in intelligent robots and rescue relief in the future.