We have developed a new unilateral master-slave hand system. The master system consists of a master arm which has a 3-DOF parallel link mechanism and a 3-DOF wrist mechanism, and a dataglove that is usually used for a virtual reality system. The slave system has a 6-DOF arm and a 16-DOF four-fingered hand. In general, a slave system is controlled by position with reference to a master system position. In this system, when an operator makes the slave system work on a complicated task, he must look at the slave carefully and let his arm and hand manipulate discretely. In the new master-slave system, each finger of the slave hand has a fingertip tactile sensor, and it is controlled by position and force. When an operator has knowledge of a task and handling objects and sets the slave fingertip stiffness, the operation can be performed easily by handling the master arm and hand to a rough position.

The authors are developing a multifingered robot hand which is modeled on a human hand. The aim is to identify the technologies necessary for this type of robot hand. The hand consists of 4 fingers, each with 4 joints actuated by DC motors via wires. The hand is attached to the tip of a 6-degree-of-freedom arm. The fingers and the arm are controlled by 6 32-bit microprocessor boards. Each finger has a tactile sensor on the fingertip. This consisting of a silicone rubber cap with a cavity filled with an incompressible fluid. Using these sensors and potentiometers mounted at one side of each joint, contact forces and positions of the fingertips are controlled. Three or four fingers grasp an object cooperatively when each finger is force-controlled using the tactile sensors independently. Evaluation tests of the position and the force control were executed, and experiments requiring the robot hand to pick up a pen and write characters were conducted.