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Theory and Applications of Modular Reconfigurable Robotic Systems


Chen, I-Ming (1994) Theory and Applications of Modular Reconfigurable Robotic Systems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/2AAA-RY45.


A modular reconfigurable robotic system consists of various link and joint units with standardized connecting interfaces that can be easily separated and reassembled into different configurations. Compared to a fixed configuration robot, which is usually a compromised design for a limited set of tasks, a modular robot can accomplish a large class of tasks through reconfiguration of a small inventory of modules. This thesis studies how to find an optimal module assembly configuration constructed from a given inventory of module components for a specific task. A set of generalized module models that bear features found in many real implementations is introduced. The modular robot assembly configuration is represented by a novel Assembly Incidence Matrix (AIM). Equivalence relations based on module geometry symmetries and graph isomorphisms are defined on the AIMs. An enumeration algorithm to generate non-isomorphic assembly configurations based on this equivalence relation is proposed. Examples demonstrate that this method is a significant improvement over a brute force enumeration process. Configuration independent kinematic models for modular robots are developed, and they are essential for solving the task-optimal configuration problem. A task-oriented objective function is defined on the set of non-isomorphic module assembly configurations. Task requirements and kinematic constraints on the robot assembly are treated as parameters to this objective function. The task-optimal configuration problem is formulated as a combinatorial optimization problem to which genetic algorithms are employed for solutions. Examples of finding task-optimal serial revolute-jointed robot configurations are demonstrated. In addition, the applications of modular robots to planning multifinger grasping and manipulation are developed. Planning two-finger grasps is done through finding antipodal point grasps on smooth shaped objects. Planning n-finger grasps is achieved by defining a qualitative force-closure test function on the n-finger grasps on an object. Applications of this test function to manipulation task and finger gaiting are illustrated.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:configuration design; nonemodular robots; reconfigurable robots; Task-based optimization; (Mechanical Engineering)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Mechanical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Burdick, Joel Wakeman
Thesis Committee:
  • Burdick, Joel Wakeman (chair)
  • Antonsson, Erik K.
  • Culick, Fred E. C.
  • Rodriguez, Guillermo
  • Murray, Richard M.
Defense Date:14 March 1994
Non-Caltech Author Email:michen (AT)
Record Number:CaltechETD:etd-10202005-090745
Persistent URL:
Chen, I-Ming0000-0002-4831-3781
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4189
Deposited By: Imported from ETD-db
Deposited On:20 Oct 2005
Last Modified:30 Aug 2022 21:22

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