Tactile sensors and the gripping challenge: Increasing the performance of sensors over a wide range of force is a first step toward robotry that can hold and manipulate objects as humans do

The three major types of tactile sensors currently available, namely optical sensors, conductive elastomer sensors, and silicon strain gauges, are discussed. Attention is also given to the new tactile sensing possibilities that are opening up as more data on the human skin become available. The principles of ultrasonic sensing are discussed.