Complex Task Completion with Redundant Serial Manipulators

Presently, advanced (redundant) manipulators are used sparingly and inefficiently to complete complex tasks despite the many advantages they have when compared to their non-redundant counterparts. Attempts by the Department of Energy to apply the potential advantages of redundancy to decontamination and dismantling processes have met with numerous complications. Yet, the decision to use them extensively and immediately in a variety of applications has already been made. Robonaut, a hybrid serial/parallel redundant robot (with 18+ DOF) being developed by NASA, has a scheduled launch date within the decade, and will be used to perform complex tasks in space. Industrial use of intelligent automation for complex task completion is virtually non-existent, and where it does exist, redundant chains are not used. It is the goal of this research effort to develop and demonstrate a complex task completion methodology using the redundant test bed available at the University of Texas. A traditional engineering design approach has been applied to the problem. First the nature of the problem is extensively described. Issues include those associated with redundant manipulators, their control, and the characterization of the task (tool) space. Summaries of the mathematical background, system model and demonstration testbed are also presented. The technical objectives of this research are analyzed and a particular solution is determined to tackle each of the ascertained issues. These decisions are made based on metrics used by any engineer: safety, correctness, application of existing technologies, time constraints, cost, and dependability of existing or proposed solutions. Solutions to the three fundamental problems are presented. These are redundancy resolution, force/motion control, and criteria/task characterization and matching. An attempt is made to segregate these aspects of the problem so that each may be improved without forcing a complete reanalysis of the problem.