A New Constrained Shape Deformation Operator With Applications in Footwear Design

In this paper, we address a problem that arises in several engineering applications: the deformation of a curve with constraints on its length. Since length is an integral property, typically computed by numerical methods, therefore implementing such shape change operations is non trivial. Recently some researchers have attempted to solve such problems for multi-resolution representations of curves. However, we take a differential geometric approach. The modification problem is formulated as constrained optimization problem, which is subsequently converted to an unconstrained min-max problem using Lagrangian multipliers. This problem is solved using the Uzawa method. The approach is implemented in MATLAB™, and some examples are presented in the paper.

Development of a Multi-Project Production Planning and Scheduling System With Agent Technology

This study intends to propose an intelligent system with agent technology in order to realize integration and cooperation of multi-project production planning and scheduling process. The agent-based system framework, in which various intelligent agents worked together to perform multi-project production planning and scheduling tasks in an autonomous and collaborative way, is put forward. The system consists of three categories of agents and functional definition of each intelligent agent is presented. Moreover, agents communication mechanism and cooperation sequence diagram are proposed. Furthermore, an intelligent algorithm based on fuzzy comprehensive evaluation is designed to resolve competition conflicts among the agents. Finally, an experiment example was illustrated and the algorithm was demonstrated feasible and efficient.

Virtual Reality Based Multi-Modal Teleoperation Using Mixed Autonomy

A multi modal teleoperation interface is introduced featuring an integrated virtual reality based simulation augmented by sensors and image processing capabilities on-board the remotely operated vehicle. The proposed virtual reality interface fuses an existing VR model with live video feed and prediction states, thereby creating a multi modal control interface. Virtual reality addresses the typical limitations of video-based teleoperation caused by signal lag and limited field of view thereby allowing the operator to navigate in a continuous fashion. The vehicle incorporates an on-board computer and a stereo vision system to facilitate obstacle detection. A vehicle adaptation system with a priori risk maps and real state tracking system enables temporary autonomous operation of the vehicle for local navigation around obstacles and automatic re-establishment of the vehicle’s teleoperated state. As both the vehicle and the operator share absolute autonomy in stages, the operation is referred to as mixed autonomous. Finally, the system provides real time update of the virtual environment based on anomalies encountered by the vehicle. The system effectively balances the autonomy between human and on board vehicle intelligence. The stereo vision based obstacle avoidance system is initially implemented on video based teleoperation architecture and experimental results are presented. The VR based multi modal teleoperation interface is expected to be more adaptable and intuitive when compared to other interfaces.

Cognitive Control Technology for a Self-Optimizing Robot Based Assembly Cell

In the face of global competition there is a great danger for countries with high labor costs (e.g. Germany) to lose more and more production plants to low-wage countries. Almost inevitably there will be a relocation of after-sales services as well as of research and development. Eventually this will cause a significant decline of wealth. For this reason especially high-wage countries are always striving for higher productivity of production processes. On the other hand the products have to be of high-end quality to ensure an advantage in the market. Thus there is an obvious dilemma between planning-orientation and value-orientation which has to be resolved. This could possibly be obtained by shifting planning efforts to the runtime system and at the same time enabling the system to adapt to changing requests and circumstances. In order to get there, automation technology is definitely playing a key role in present-day highly automated production processes. Unfortunately classical automation technology has not been supporting this kind of self-organizing, self-controlling and self-optimizing behavior. This paper introduces an approach to make production systems more “intelligent” based on the idea of a cognitive control architecture. At first the motivation and the research vision are introduced followed by an outline of the research approach. As a concrete example of an application a robot based assembly cell is described. The methods used and insights gained so far are presented in the second part, followed by an outlook towards future activities.

A New Concept for Requirements Driven Project Planning in an Integrated PLM Environment

Integration in today’s heterogeneous PLM environments is a key factor in all development phases. This paper describes a methodical approach to integrating requirements modeling into a PLM environment. The specific focus of integration aspects is on project planning of complex mechatronic products with recurrent character based on requirements specification documents. Function and process orientation serves as a basis for the integration. It is discussed how development projects teams can benefit by generating project plans including resource estimations and predefined interfaces to bordering disciplines along the development process. With the help of semantic parsing methods of natural language requirements and through a generic classification system a requirement based product and process model is generated. This model is then taken as the basis for deriving product and process related information. Through domain specific ontology’s generic project and resource plans are generated with the help of the proposed methodology.

A Tool to Integrate Design for Assembly During Product Platform Design

To survive in the current market, many companies are moving toward design and development of product families using a platform approach. To effectively develop a family of products, companies have to consider both component and assembly perspectives. The assembly perspective has many issues associated with it for developing common platforms, which includes assemblability evaluation for the entire family. Application of Design for Assembly techniques to evaluate product family will require modifications to the current single product DFA method. In this paper a product family DFA tool and guidelines are presented. The application of this product family DFA tool is illustrated using Walkman® and Coffeemaker product family.

Interactive Multi-Modal Visualization Environment for Complex System Decision Making

Decision making in a complex system requires a large amount of data, and real time interaction and visualization tools become effective solutions. Constant improvement in computer graphics technology has encouraged the research of developing better and more efficient ways of interacting and visualizing complex three-dimensional image data. This paper presents a unique software framework for interacting and visualizing complex volume image data in a virtual environment. For efficient user interactions, a wireless gamepad controller is used as the main input device. The buttons and joysticks on the gamepad controller are intuitively mapped to perform different functions depending on the feature mode that the software is currently in. Apart from the general viewer, an extension of the software also reads in standard format patient medical images such as CT/MRI scans. As an effective decision making tool, the software allows the user to apply fast pseudo-coloring and multiple interactive oblique clipping planes for an immersive detailed examination of any 3D model. In the medical imaging extension of this software, it features the ability for the user to select a specific range of tissue densities to render and an endosurgery planning mode that allows a surgeon to place simulated laparoscopic surgical instruments in a virtual model of the patient. The developed software allows for better interaction with complex volume data for use as a decision making and evaluation tool.

Overview of Remaining Useful Life Methodologies

Nowadays, it is imperative for products to function properly each time they are used. If a product fails during its use, it may have disastrous consequences. Estimating remaining useful life (RUL) of a product is a key to prevent such disasters, improve its reliability, provide security and reduce maintenance and operational cost. Naturally, estimation of RUL of a product and develop methodologies for the same is proving an interesting domain for researchers. This paper gives an overview of RUL estimation methodologies applied to various products. It also discusses hybrid methodologies which improve RUL estimation accuracy and overcome limitations of the individual methodologies. As this is an emerging area, these methodologies have been applied to only a handful of products. A list of these products is provided with references. A quantitative metric that measures the relative important characteristic differences among different methodologies is given. This paper concludes with few important points observed during literature review.

Monte Carlo Optimization of Two-Stage Cascade R134A Refrigeration System With Flash Chamber

Present paper studies the optimal characteristics of the two-stage cascade R134A refrigeration system with flash and mixing chambers over its operating ranges of all cycle controlling parameters. The COP, total heat rate in Qin, total work rate in Win and second law efficiency ηII are used as cycle performance parameters. Compared to the practically-limited other rate-based optimization methods and to other experimentally-optimized specific cases of cycle parameters, the application of Monte Carlo method has proved to be very effective for optimizing the cycle performance in its global sense over all cycle controlling parameters. Correlations relating performance and cycle controlling parameters are presented and discussed. Study shows that COP of the cycle can reach a value of 8 at intermediate pressure P2 of about 200 kPa, and a maximum value of 9.92 at about 370 kPa and 720 kPa, beyond which COP goes as low as 4.2. P2 alone has no significant effect on Qin, Win and ηII unless values of other controlling parameters are specified. Values of Qin, Win and ηII can reach as high as 94 kW, 23 kW and 0.85 and as low as 6.8 kW, 1.1 kW and 0.57 respectively depending on other cycle parameters. Neither pressure ratio nor volume ratio of the HP compressor has any effect on Qin, Win or ηII. However, the ratio of inlet to exit temperatures of the condenser has the greatest effect on both ηII and the volumetric specific work of the HP compressor, which is about double the value of the volumetric specific work of the LP compressor. Study shows an almost linear relationship between the two mass flow rates in the upper and lower loops of the cycle, where its value in the lower LP loop is about 75% that in the upper HP loop. Findings of the present work as well as the elaborate application of Monte Carlo method to real cycles can greatly open the way for reducing the trade-off design methods currently used in developing such systems as well as direct the useful experimentations and assessment of such designed systems.

Optimization of a Hydraulic Mixing Nozzle

In industry, mixing tanks are used to homogenize two or more different products that have been combined. This work investigates the use of computational fluid dynamics (CFD) to seek an enhanced design for a hydraulic mixing nozzle. This paper outlines a method for a numerical specification of a nozzle design and generation of a CFD model to analyze it. Characteristics that influence jet distance and trajectory, such as horn size, shape, and entrainment area, are reviewed. The relative importance of each of these traits and which traits have the most significant impact on the quality of a given design are explored. Suggestions for nozzle design are summarized. This information allows the most limiting factors of a tank mixing design to be mitigated to the largest extent possible. Currently industry uses magnification ratio (the ratio of flow out of the nozzle divided by the forced flow through the nozzle jet) for mixing tank nozzle design. This paper illustrates that using magnification ratio or velocity alone does not result in an optimized design. These factors must be weighted to obtain a design that balances these factors to mix the geometry of fluid volume. Additionally, this work shows that nozzle placement is perhaps more significant than nozzle design for optimum mixing with minimum power consumption.