Design, Control, and Reconfiguration Planning for Octagonal Modular Robot
Date Issued
2011
Date
2011
Author(s)
Shiu, Ming-Chiuan
Abstract
A reconfigurable robot is made of a set of robotic modules with the ability to change the shape by having cooperation among the multiple robot modules. In this thesis, we address the issues about module’s design and control and about the problem with reconfiguration planning of the reconfigurable robot in particular with octagonal modules.
First, we introduce the module’s design of the reconfigurable robot with octagonal modules. The design concept, mechanical structure, electrical processing unit, actuator dissection and reconfiguration examples of the proposed robotic modules are presented in detail. It is noteworthy that the key actuation of the robotic modules and, in turn, robotic reconfiguration is driven only by the E-type electromagnets, and modules with different shapes are implemented for versatile applications. The feasibility of the proposed robotic modules has been extensively tested.
Second, we also introduce module-on-module rotation model, and derive the dynamics of a reconfigurable robot in Hamiltonian formulation. Using this approach we have implemented nonlinear control techniques including feedback linearization and stability analysis are applied successfully. The simulations are provided to validate the proposed method, and its advantages are also discussed.
Third, this thesis presents a new approach to the problem with reconfiguration planning. We first propose a representation of the relative orientation between a module and its connected neighbors, from which an orientation adjacency matrix incorporating the concept of depth first search (DFS) and fixed coordinate setting is derived. Next, the distance measurement between any two configurations of the robot based on weighted graph matching problem (WGMP) method is introduced so that the lower bound on the number of motion steps from one configuration to another can be explicitly assessed. An A* search algorithm based on the above lower bound estimate for reconfiguration planning is developed to generate the optimal reconfiguration motion. To validate the proposed new approach, it has been demonstrated in simulations for two kinds of robots with two different types of modules, namely Octamods and hexagonal modules. Several simulation results and experiments are provided, which have shown promising results with impressive effectiveness.
Overall, this thesis represents significant progress in design, control and reconfiguration planning algorithm of the reconfigurable robot with octagonal modules.
Subjects
Electromagnet
modular robot
reconfigurable robot
feedback linearization
reconfiguration planning algorithm
Type
thesis
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