Developing a quantitative intelligent system for implementing concurrent engineering design

North American undergraduate mechanical engineering design education has failed to meet the needs of industry in educating students in effective design philosophies typified by the concurrent engineering design philosophy. Current programmes emphasize traditional engineering analysis courses, leaving little room for truly educating the students in the fundamentals of mechanical engineering design. This paper uses the concurrent engineering design paradigm to design a programme for the education of students in mechanical engineering design. The basics of concurrent engineering design are outlined, the failings of typical design education stated, and an exploration of the required features of a new design curriculum presented.

This paper presents ongoing work to standardize model-based system engineering as a complement to point design development in the conceptual design phase of deep space missions. It summarizes two first steps towards practical application of this capability within the framework of concurrent engineering design teams and their customers. The first step is standard generation of system sensitivities models as the output of concurrent engineering design sessions, representing the local trade space around a point design. A review of the chosen model development process, and the results of three case study examples, demonstrate that a simple update to the concurrent engineering design process can easily capture sensitivities to key requirements. It can serve as a valuable tool to analyze design drivers and uncover breakpoints in the design. The second step is development of rough-order- of-magnitude, broad-range-of-validity design models for rapid exploration of the trade space, before selection of a point design. At least one case study demonstrated the feasibility to generate such models in a concurrent engineering session. The experiment indicated that such a capability could yield valid system-level conclusions for a trade space composed of understood elements. Ongoing efforts are assessing the practicality of developing end-to-end system-level design models for use before even convening the first concurrent engineering session, starting with modeling an end-to-end Mars architecture.

As products become ever more diversified, their life cycles are becoming shorter. To reduce production costs, increased process automation and concurrent design are priorities. Therefore, a collaborative integrated design system is crucial in the mold design and manufacturing process. This research develops a collaborative navigation system for concurrent mold design within the computer-aided design (CAD) browser, using Pro/Web.Link as the core tool. Providing both concurrent engineering and collaborative design functions, the navigation system is capable of assisting designers in accomplishing 3D mold development efficiently and accurately with the help of the standard component library and design decision-making system. The results show significant time savings over other mold design process methodologies.

Concurrent engineering: Automation, tools, and techniques

An integrated graphical user interface (GUI) for concurrent engineering design of mechanical parts

An Internet-enabled integrated system for co-design and concurrent engineering

In this paper, we apply Taguchi Methods in the framework of concurrent engineering design for robot-based manufacturing sys tems to obtain higher accuracy and repeatability for robot end-effectors. It is well known that the configurations of robot end-effectors in workspace will affect the accuracy and repeatability Taguchi Methods are employed to find the configuration and location within which the accuracy and repeatability are the best. The optimal position with higher accuracy and repeatability is determined by using the signal-to- noise ratios (S/N ratios), which are defined according to the "smaller-the-better" characteristics of Taguchi Methods to measure the accu racy and repeatability The results match well with the theoretical analysis of the repeatability and accuracy of the end-effector based on the kinematic relationship. In addition, we also study the random and systematic errors due to joint uncertainties and examine their effects on the accuracy and repeatability. The analysis using S/N ratios yields results that are consistent with expectation. The results demonstrate that Taguchi Methods and S/N ratios are very useful tools in design for accuracy and repeatability of robotic end-effectors. The sensitivity and consistency of accuracy with respect to the tolerance of joint angles are represented by 3D surfaces. The tolerance design is per formed, using the sensitivity analysis, to satisfy requirements stipulated by design criteria One of the significant results of consistency analysis is the "threshold" value of tolerance for concurrent engineering design considerations. Simulation results show that the consistency of accuracy and repeatability will be increased dramatically once the tolerance is below such a threshold Both sensitivity and consistency analysis are shown to be important in tolerance design for achieving the desired accuracy and repeatability and for enhancing quality.

Over the past decade the software products available for solid modeling, dynamic, stress, thermal, and flow analysis, and computer-aiding manufacturing (CAM) have become more powerful, affordable, and easier to use. At the same time it has become increasingly important for students to gain concurrent engineering design and systems integration experience. The purpose of this paper is to communicate the dramatic effect that the new software has had on the way that mechanical drawing and engineering design are taught at Daniel Webster College (DWC). The two year design experience at DWC is more extensive than the design experience that students normally have during the first two years of most four-year engineering programs. The evolution of this design experience will be presented. Three of the presenters of this paper are students. Two will present robotic arm projects; the third will present a supersonic gun project.

Description d'un logiciel d'enseignement assiste par ordinateur, ayant pour but d'apprendre aux eleves ingenieurs a travailler dans un environnement concurrentiel

Improved Multidisciplinary Multiobjective Collaborative Optimization Technique Based on NSGA-II Algorithm1

This paper presents a method for conducting automated concurrent design using combined feature, tolerance, production process and cost models. The introduced features are defined and examined in terms of design function, manufacturing method, and geometric shape and accuracy. The integrated design model has three functions: (a) facilitating the generation of all feasible designs by design feature-based knowledge reasoning using an intelligent CAD system; (b) representing various design information using the geometric primitives of a conventional CAD system; (c) describing a design using production process-oriented manufacturing features for evaluating manufacturability and production costs. This approach can incorporate manufacturing consideration into design phase and identify a cost-effective design satisfying given design functions and achieving minimum production costs. Functions of a prototype system are illustrated using an example.

Estimating the annual production cost is a crucial component in long range capacity planning for electric utilities. Traditional simulation-based methods are quite expensive in terms of computer resources (space and time), while simpler mathematical programming-based models generally assume a linear variable production cost. This paper presents a method that incorporates quadratic production costs for each unit and uses optimization submodels to develop a system production cost versus output curve. The method is tested using data from a large southeastern utility. Production cost estimates within one percent of the estimates from a large simulation model were obtained with a small fraction of the simulation model's computing time. The concluding section discusses how the new method might be incorporated in procedures for capacity planning.

Ambulatory surgery centers (ASCs) are freestanding facilities that specialize in surgical and diagnostic procedures that do not require an overnight stay. While it is generally assumed that ASCs are less costly than hospital outpatient surgery departments, there is sparse empirical evidence regarding their relative production costs. To estimate ASC production costs using financial and claims records for procedures performed by surgery centers that specialize in gastroenterology procedures (colonoscopy and endoscopy). We estimate production costs in ASCs that specialize in gastroenterology procedures using financial cost and patient discharge data from Pennsylvania for the time period 2004-2013. We focus on the 2 primary procedures (colonoscopies and endoscopies) performed at each ASC. We use our estimates to predict average costs for each procedure and then compare predicted costs to Medicare ACS payments for these procedures. Comparisons of the costs of each procedure with 2013 national Medicare ASC payment rates suggest that Medicare payments exceed production costs for both colonoscopy and endoscopy. This study demonstrated that it is feasible to estimate production costs for procedures performed in freestanding surgery centers. The procedure-specific cost estimates can then be compared with ASC payment rates to ascertain if payments are aligned with costs. This approach can serve as an evaluation template for CMS and private insurers who are concerned that ASC facility payments for specific procedures may be excessive.

7. Concurrent engineering and collaborative design

An efficient mechanical product design process implies the evaluation of many alternatives in a short time and rapid product changes on the basis of emerging needs. Product cost is one of the main factors in order to choose the most promising solution. Hence its accurate estimation in the design phases is fundamental. The main problem is the vast amount of knowledge that has to be managed in order to make robust evaluations. Features based 3D CAD models implicitly contain part of needed information. But such information has to be elaborated by adopting suitable rules based on manufacturing knowledge. In this context, the paper presents an approach and the related knowledge-based system able to automatically make reliable cost estimation starting from the 3D CAD model. The approach is based on the manufacturing knowledge formalization, on the geometrical and non-geometrical feature automatic recognition and, finally, on the mapping between manufacturing operations and modeling features. In order to validate the system performance case studies are reported.KeywordsCost estimationFeature recognitionKnowledge-based systems