Modular reconfigurable machines: theory and application

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Modular Reconfigurable Machines (MRMs) represent a paradigm shift in the history of machines, because they are able to rearrange their modules and change their structures according to environment and task requirements. Although a number of MRMs have been developed around the world, they are still controlled by methods previously developed for traditional machines, but recently adapted to MRMs on a case-by-case basis. When the MRM changes its configuration, all equations, including kinematics, dynamics, kinetostatics, and calibration, must be derived all over again. Therefore, new theory must be developed in order to deal with the varying topological nature of MRMs. In this proposed research, the objective is to develop a module-based theory for effective analysis and control of MRMs. This research includes five components. The first component is module modeling in which the modules of MRMs will be classified in terms of the number and combinations of motion axes, and then a method will be developed to model the connectivity between adjacent modules. The second component is kinematic modeling in which a module-fixed coordinate frame will be used for each type of modules, and a zero-reference plane method will be used to unify the kinematic representation of all modules with respect to the global coordinate frames. The third component is system modeling in which transformation functions will be developed between adjacent modules, including pose/twist (motion), wrench (force), deformation and error, and then these transformation functions will be embedded in the module function blocks, which will be created to automatically generate the system equations for various analyses and controls of MRMs. The fourth component is configuration optimization in which both an enumeration method and Generic Algorithms (GA)-based method will be developed to search for an optimal configuration of a MRM for given task requirements. The last component is industrial applications in which two types of MRMs will be studied, one being modular reconfigurable machine tools (MRMTs) and the other being modular reconfigurable robots (MRRs), with applications to manufacturing and aerospace.