Design of a Tactile Sensor for Robot Hands

Grasping and manipulation of objects, as well as the capability interacting safely with the environment (possibly including also humans), is a fundamental task for a humanoid robot. In order to tackle these issues a great effort has been put for over two decades to develop robot hands or mechanisms emulating the grasping capabilities of a human hand (Salisbury & Mason 1985; Jacobsen et al. 1986; Melchiorri & Vassura 1992; Lotti et al. 2004; Butterfass et al. 2001; Carrozza et al. 2003; Kargov et al. 2005; Caffaz & Cannata 1998; Lane et al. 1997; Hashimoto 1995). However, grasping and manipulation control also rely the availability of suitable contact and force feedback. In this chapter we first present a survey of recent advances in the area of skin-like tactile sensors for both robot hand and for robot bodies. In the second part we will discuss the design of an embedded and modular tactile/force sensor to be installed on the phalanges of a robot hand. Each sensor consists of a distributed array of analog tactile elements and an integrated three-component force transducer with embedded analog and digital electronics. The tactile sensor consists of a matrix of electrodes etched on a flexible printed circuit board covered by pressure conductive rubber. The force sensor is instead an off-the-shelf integrated three components micro-joystick.