with multifingered grippers or the hands have been developed all around the world. Many different approaches have been taken, anthropomorphic and non-anthropomorphic ones. Heavy industrial production often appears in the workpiece handling and frequent long-term, monotonous operation, if there is no robots that labor intensity of workers is very high, sometimes even with employees driving, speed greatly retard this situation, using manipulator is very effective. In addition, it can operate at high temperature, low temperature, deep water, space, reflection and other toxic and polluted environment. It shows its superiority, and has broad the  prospects for development.Not only the mechanical structure of such systems was investigated, but also the necessary control system. With the human hand as an exemplar, such robot systems use their hands to grasp perse objects without the need to change the gripper. The special kinematic abilities of such a robot hand, like small masses and inertia, make even complex manipulations and very fine manipulations of a grasped object within the own workspace of the hand possible. Such complex manipulations are for example regrasping operations needed for the rotation of a grasped object around arbitrary angles and axis without depositing the object and picking it up again. In this paper an overview on the design of such robot hands in general is given, as well as a presentation of an example of such a robot hand, the Karlsruhe Dexterous Hand II. The paper then ends with the presentation of some new ideas which will be used to build an entire new robot hand for a humanoid robot using fluidic actuators.

Keywords: Multifingered gripper, robot hand, fine manipulation, mechanical system, control system 

1 Introduction

The special research area 'Humanoid Robots' founded in Karlsruhe, Germany in July 2001 is aimed at the development of a robot system which cooperates and interacts physically with human beings in 'normal' environments like kitchen or living rooms. Such a robot system which is designed to support humans in non-specialized, non-industrial surroundings like these must, among many other things, be able to grasp objects of different size, shape and weight. And it must also be able to fine-manipulate a grasped object. Such great flexibility can only be reached with an adaptable robot gripper system, a so called multifingered gripper or robot hand.

The humanoid robot, which will be built in the above mentioned research project, will be equipped

with such a robot hand system. This new hand will be built by the cooperation of two institutes, the IPR (Institute for Process Control and Robotics) at the University of Karlsruhe and the IAI (Institute for Applied Computer Science) at the Karlsruhe Research Center. Both organizations already have experience in building such kind of systems, but from slightly different points of view.

The 'Karlsruhe Dexterous Hand II' (see figure 1:  Karlsruhe Dextrous Hand II from IP) built at the IPR, which is described here in detail, is a four fingered autonomous gripper. The hands built at the IAI (see figure 17: fluidic hands developed at the IAI) are built as prosthesis for handicapped people.

The approach taken so far will be presented and discussed in the following sections, as it founds the basis for the novel hand of the humanoid robot.

Figure 1:  Karlsruhe Dextrous Hand II from IP 

Proceedings of the IEEE-RAS International Conference on Humanoid Robots2001 

2 General structure of a robot hand

A robot hand can be split up in two major subsystems:

• The mechanical system

• The control system

The mechanical system, further described in section 3, can be subpided into: