Forming complex dextrous manipulations from task primitives

This paper discusses the implementation of complex manipulation tasks with a dextrous hand. The approach used is to build a set of primitive manipulation functions and combine them to form complex tasks. Only fingertip, or precision, manipulations are considered. Each function performs a simple two-dimensional translation or rotation that can be generalized to work with objects of different sizes and using different grasping forces. Complex tasks are sequential combinations of the primitive functions. They are formed by analyzing the workspaces of the individual tasks and controlled by finite state machines. We present a number of examples, including a complex manipulation removing the top of a child-proof medicine bottle-that incorporates different hybrid position/force specifications of the primitive functions of which it is composed. The work has been implemented with a robot hand system using a Utah-MIT hand