Scheme Generation And Optimality Of Mechatronic Systems

The generation of system scheme requires high degree of creativity. Generally speaking, existing scheme generation of mechatronic systems relies largely on designer's empirical experience, without developing into scientific design methodology. Therefore, the key of generating creative schemes is to progress from present empiricism-based design to an approach guided by scientific theories and methodology.This dissertation studies the mechatronic system that realizes the function of working machine, unfolds a systematic and in-depth investigation into the theory and methodology of creative scheme generation of mechatronic systems, and is composed of the following sections.1) Constructing the function structure of mechatronic systemDiverse technology systems differ greatly in their interpretation and description of the term'function'concerning physical effect, material/energy/information transformation, as well as logical relations in statistical arithmetic. Chapter One constructs the function structure of mechatronic system, proposes and explicates basic characteristics of mechatronic system and the relations between these characteristics, and formulates fundamental principles in mechatronic system design, so as to lay a solid foundation for further attempts to propose a design model and methodology for mechatronic systems.2) Proposing logical structure of mechatronic system, and updating the tri-subsystem design methodA mechatronic system is essentially a mechanical system characteristic of modern technology. A mechatronic system, from the perspective of function, is divided into the two functional modules of control and execution. Moreover, the logical structure of mechatronic system is manifest as element layer and system layer.Chapter Two proposes the model of scheme design process of mechatronic system based on mechatronic element, and updates the design method of tri-subsystem. A swift, efficient, reliable and effective approach to mechatronic system design applies the element design theory, i.e., with distributed control functions and independent control loops, to mechatronic system design, so as to realize the scheme through selectively employing appropriate components.3) Presenting scheme generation reasoning and computer-aided solving strategyIn accordance with the layeredness of transformation function and the multi-element nature of purpose function (effect), we construct characteristics models of transformation function and purpose function (effect), and propose function space prolongation of creative scheme generation of mechatronic system as well as the reasoning trajectory. Furthermore, we present a computer-aided process model of scheme generation, in which transformation function, technology, purpose function and working principle realize circular solving. We then proceed to put forward the formal expression of'and'/'or'tree of scheme generation to be applied to computer processing, and probe into the corresponding solving arithmetic.4) Explicating information-content based optimality of mechatronic system schemeChapter Four applies the basic principles of axiom design (information axiom in particular) to the optimality process of mechatronic system scheme, and analyzes thoroughly the indeterminacies ubiquitous in the deign process. Taking into account the qualitative and quantitative attributes and the time-variable nature of the function and state of mechatronic system, we present a set of concepts, such as information-content based function, design parameter, mechatronic ratio and control efficiency. We also propose a series of principles for optimal scheme generation of mechatronic system, such as time-domain parameter control principle, maximum information optimality principle, and maximum control efficiency principle, so as to proffer a new design direction to effectively improve the performance of mechatronic systems.5) Elucidating scheme representation of object-oriented mechatronic systemIn response to the research status-quo that over-emphasizes physical structure and behavior while ignoring logical structure and behavior of the system, we apply object-based thinking to the scheme solving of structure, behavior and principle of mechatronic system.Logical structure of mechatronic system can be expressed as object-oriented reference model or UML-based class diagram (UML, Unified Modeling Language). In order to describe the interface (communication) behavior of object (as well as system and environment) and render interaction visible, we employ MSC (Message Sequence Charts) to express the logical behavior of mechatronic system. Furthermore, we apply UML and MSC to express the principle scheme solving of mechatronic system.6) InstantiationWe conduct a thorough investigation into the scheme design and optimality of such mechatronic systems as rapid prototyping systems (in particular, Slicing Solid Manufacturing System, and Melted Extrusion Molding System) and CD player, which serves to testify the theory and methodology proposed and developed in this dissertation.