Creating Adroit Mechanisms by Using Large Numbers of Simple Homogeneous Structures

The project described in this paper investigates the idea that, in some circumstances, the functions of a complex mechanism can be performed by a large number of simpler units. There are example in nature that support this approach. In the case of locomotion this is seen in the starfish that walks on a large number of tube feet. The structure and control of starfish feet are both simpler than would be the case if the starfish had a small number of more complex legs. There are similar examples in the case of manipulation. Cilia, which line the bronchial passages, work together to transport foreign particles out of the lungs. Individual cilia are simple and their great numbers provide reliability through redundancy. In this paper the idea of creating a versatile system from many elementary units is developed in the context of a multi fingered gripper. The prototype gripper has eight simple, one degree-of-freedom fingers. It is found that this gripper provides excellent grasp stability for a wide range of object shapes and is able to translate, rotate and measure the surface profile of gripped objects. This paper outlines the gripper design together with algorithms for performing grasping, repositioning and object recognition. Experimental results are also presented which illustrate the performance of the gripper.