Research On The Theory And Method For Reconfigurable Machine Tool Design

The uniqueness of the Reconfigurable Manufacturing System (RMS) is that the structure of the system as well as its machines and controls can be rapidly and cost-effectively converted in response to the demand changes of market/custom. Reconfigurable Machine Tool (RMT) and its systemic design methodology are the cornerstones of RMS. The design of RMT is not just configuring the existing modules for a specific task, but rather a design of a new type of machine, which can illustrate the ideas of reconfiguration science. With financially supported by the Provincial Natural Science Foundation of Zhejiang province (NO: 598042), the theory and method for RMT design are systematically studied in this dissertation. The thesis aims to create the conditions for building the systematic theory of RMT, implementing and developing, as well as provide theoretical and methodological guidance for implementing RMS successfully. Based on the analysis of the requirement developments, design evolvements, and existent questions of the conventional machines, the challenges and requirements of RMT design are discussed. The research status and lacks of RMT design are analyzed in the detail. Based on it, the origin, objective and significance of the research in this dissertation are presented, as well as the main research contents. In allusion to establish the systematic architecture of RMT theory, the definition and intension of the RMT concept are expounded. In the view of the reconfiguration, the cost model of machine is established, and the essence of RMT is revealed. In the view of realizing the reconfiguration and customized flexibility & control of RMT, the basic principles and characteristics of RMT are discussed, and a RMT design methodology based concurrency of process planning and machine configuration building is proposed, as well as the architecture and steps of the design methodology. All of above established the scientific base for the subsequent research of this dissertation. As designing for an operation family is the essence of RMT design, so the method for identifying the operation family from the operation demands of part family is proposed, and the operation family must be machined on the same RMT. The tolerance-based and concurrency-based clustering principles and conditions for single part are given, and the pattern recognition issue for the similar special operation clustering in the concurrency-based clustering is discussed, and the mathematic model, category, and algorithm of the pattern recognition are proposed. The similarity measure between the single part operation clustering is presented, and the problem of multi-part operation clustering using modified k-means (k-modes) algorithm is studied. A method for groupingthe operation clustering (include single part and multi-parts) based on the fuzzy clustering analysis is given, so the set of operations required on the same RMT is decided, that is called operation family (because the set of operations are grouped from different parts in a part family). Using the rule-based method, the sequence of the operation clustering and the operation sequence in each operation clustering are obtained, thereby the feasibility of RMT designed is ensured.Aim at to realize the customized flexibility of RMT, a modular design method for mechanical system of RMT which based on the screw and graph is presented. Within this method, the kinematics modeling of RMT basic functions and machine tool modules are established using screw method. By comparing the twist between them, each function (kinetic and structure) is then mapped to a feasible set of modules (or named building block) in the module library. Using the graph theory, a set of feasible structural configurations of the RMT is designed, as well as the connectivity of each machine module is defined. A method for generating a series alternative RMT configuration and reconfiguration (graph) met the operation requirements is given. In order to realize the reconfiguration online of RMT and maximumly use the machine resources, a design method for reconfigurable machine module is developed using screw method. Employing such machine module, the functionality of an RMT can be changed without replacing modules.In order to realize the objective that synchronously reconfigure the control and machine of RMT, a modular design method for RMT controller is proposed. Within this method, both the entire controller and its individual control module are acted as a set consisting of a Finite State Machine (FSM) and input & output event set pairs, and each pair of input & output event set was defined as a port of the control module, and the input event set on a given port formed the port acceptable Language. Thus, when the mechanical modules are assembled, the control modules will be connected using port Language, and the entire controller is created or reconfigured. The definitions of control module with FSM and module combination are given. A design and construction principles of modular controller are proposed, and the principles correctness are proved. Once the control modules are properly designed and connected, the resulting controller is guaranteed to be controllable. When the demand is changed, the control module can be reused by redefining the port language without change the controllability.In order to minimize the redundancy capacity and functionality of machine, a configuration design method for configuration path of RMT in the early stage of configuration design is proposed, which is designed for changing requires scenario. By evaluating the configuration economics and reconfigurability over the lifetime of RMT, the method...