A Prototype Tactile Sensor Array.

Although there are many potential applications for a tactile sensor array, very few practical implementations of such a sensor have been demonstrated. A practical tactile array sensor needs to be very durable, have a high resolution, have a small physical size, be relatively insensitive to noise, and have a compliant surface. In addition there is both physical and electrical coupling between elements of the array which should be eliminated or reduced as much as possible. In order to investigate some of these problems, a prototype tactile sensor was constructed. The sensor was made of a sheet of conductive foam sandwiched between layers of conductors. When the foam is compressed at some point, the resistance through the foam decreases. By selecting the appropriate conductor on each side of the foam, the resistance at any one of 256 points could be measured. The spatial resolution of the sensor was 14 inch. As a sample application, an object recognition system was implemented using the sensor. There are many questions involved in how to build a recognition system using a tactile sensor array. These includes how to separate the object from the background, what features to use, and forms of preprocessing to perform on the tactile image. The system implemented was a first step at answering the first two questions. When an object was presented to the sensor array, the resulting data was thresholded in order to separate the background from the object.