The design of a representation and analysis method for modular self-reconfigurable robots
"The Design of a Representation and Analysis Method for Modular Self-Reconfigurable Robots"
Albert W.Y. Ko
Submitted to the
Department of Industrial and Manufacturing Systems Engineering in partial fulfilment of the requirements for
the Degree of Master of Philosophy
at The University of Hong Kong
in November 2003
For modular self-reconfigurable (MSR) robots to successfully reconfigure from one shape into another, the control system (whether centralized or distributed) must have a clear idea of the robot's topological structure in order to perform motion planning. For this reason, the modules' docking status must be correctly ascertained before a self-reconfiguration. Although the type of information required to visualize the structure of a MSR robot differs with the physical design of the module, certain types of information, such as the docking orientation between two neighbouring modules and the availability of docking ports in the robot, will always be required.
This thesis presents a representation method, based on Graph Theory, which uniquely represents the topological structure of a group of connected modules using labelled planar graphs and incidence matrices. The graph contains essential information for distributed reconfiguration analysis and motion planning, and information such as the orientations of the docked joints and docking ports involved in each joint can be obtained intuitively from the labelled graph. The
incidence matrix takes the information from the planar graph and represents it in a systematic manner which can be understood by the computers.
This thesis also presents an innovative Hardware Orientation Detecting System (HODS) for detecting the orientation of a docked joint formed from two docking ports. The HODS uses a minimum number of simple tactile sensors to detect multi-orientation dockings. The method can be applied to all multi-orientation docking systems with a finite number of possible docking orientations. An analytical method is also suggested, in which simple matrix operations are used to extract and transform essential information (such as the docking ports involved in each docked joint) out of the incidence matrix into a more concise matrix. The reduced matrix contains information defining the number of docked joints within the structure and the docking ports involved in each joint. With the aid of basic kinematics or CAD analysis, the reduced matrix can be used to determine whether a structure has enough degree-of-freedom in-line to facilitate the selfreconfiguration process of the MSR robot.
Primary Supervisor: Dr. T. L. Lau
Title: Associate Professor of Industrial and Manufacturing Systems Engineering, HKU
Co- Supervisor: Dr. Henry Y. K. Lau
Title: Assistant Professor of Industrial and Manufacturing Systems Engineering, HKU
School:The University of Hong Kong
School Location:China - Hong Kong SAR
Source Type:Master's Thesis
Keywords:robots kinematics control systems design and construction motion
Date of Publication:01/01/2004