The Mechatronic System Conceptual Design Method Based On RRDOF

The essence of the concept design is to define the design issues as desired functions,and to solve the solution of the physical program of the functions. The design work in thestage has the greatest innovation space as well as huge uncertainty and ambiguity. Theexisting theory and methods of concept design provide general guidance for designers, but thewhole concept design is also mysterious. Thus, regardless of any conceptual design method,conceptual design mostly depends on the designer’s experience and inspiration rather thanknowledge.Functions are always involved in the whole design concept process, so―function‖is acritical term. In this paper, through on the in-depth research of functions, we proposed aRefined and Rigorous Definition of Function (RRDOF) and then provided a comprehensivedesign method for conceptual design of mechatronic systems according to the basic process ofconcept design and based on the definition. With the new method, designers can carry out thedesign work with definite targets and based on physical knowledge. The whole contents aresummarized as follows:(1) The function definition was studied. According to system theory and engineeringpoints, we comprehensively explore the meanings of the function. Based on the functiondefinition by Pahl&Beitz,"flow change", we proposed the refined and rigorous definition(RRDOF). Then we introduced the features of RRDOF and analyzed its difference with thefunction definition by Pahl&Beitz. In addition, we proposed the function representationmethod,"Structural descriptions with symbols plus flows".(2) The function of reasoning method was studied. The three functional reasoningpriority rules were proposed based on RRDOF. According to Rule1, we proposed the cubemodel of functional reasoning and the description method and establishing process of thecube model. Then we summarized the main features of the cube model and discussed itsapplication scope. According to Rule2and Rule3, we studied functional decompositionstrategies of the flows of materials, energy and information.(3) Concept solving method was studied. Based on the elements and description methodof the solution, we studied direct mapping solving approach (function→solution) based onexample reutilization and focused on RRDOF-based functionality search strategies andstructured design of example library. Then we studied the concept solving method based on physical principles and focused on solving strategies of physical principles based ondimensionality analysis.(4) Solution synthesizing and evaluation strategies were studied. Based on the newfeatures of RRDOF, we proposed that the essence of solution synthesizing was to addnon-functional components. Then we explored general evaluation indexes of technicalsystems to reflect the common requirements of customers and provided two synthesizing andevaluation methods respectively based on matching rule and matching functions.(5) We provided example study. The proposed conceptual design method was applied todesign the brand-new integrated road mending machine (IRMM) to gradually show the wholeprocess of the conceptual design. In contrast to the systematic model by Pahl&Beitz, theproposed method was feasible and advanced in functional reasoning.