A B S T R A C T This paper aims to provide a systematic overview of the state of the art in energy and resource efficiency increasing methods and techniques in the domain of discrete part manufacturing, with attention for the effectiveness of the available options. For this purpose a structured approach, distinguishing different system scale levels, is applied: starting from a unit process focus, respectively the multi-machine, factory, multi-facility and supply chain levels are covered. Determined by the research contributions reported in literature, the de facto focus of the paper is mainly on energy related aspects of manufacturing. Significant opportunities for systematic efficiency improving measures are identified and summarized in this area. 2012 CIRP.

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Towards Energy and Resource Efficient Manufacturing: A Processes and Systems Approach

This paper presents a benchmark data set for condition monitoring of rolling bearings in combination with an extensive description of the corresponding bearing damage, the data set generation by experiments and results of data-driven classifications used as a diagnostic method. The diagnostic method uses the motor current signal of an electromechanical drive system for bearing diagnostic. The advantage of this approach in general is that no additional sensors are required, as current measurements can be performed in existing frequency inverters. This will help to reduce the cost of future condition monitoring systems. A particular novelty of the present approach is the monitoring of damage in external bearings which are installed in the drive system but outside the electric motor. Nevertheless, the motor current signal is used as input for the detection of the damage. Moreover, a wide distribution of bearing damage is considered for the benchmark data set. The results of the classifications show that the motor current signal can be used to identify and classify bearing damage within the drive system. However, the classification accuracy is still low compared to classifications based on vibration signals. Further, dependency on properties of those bearing damage that were used for the generation of training data are observed, because training with data of artificially generated and real bearing damages lead to different accuracies. Altogether a verified and systematically generated data set is presented and published online for further research.

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Condition Monitoring of Bearing Damage in Electromechanical Drive Systems by Using Motor Current Signals of Electric Motors: A Benchmark Data Set for Data-Driven Classification

The paper proposes lab work and student competitions based on the LEGO NXT Mindstorms kits and standard LabVIEW. The goal of this combination is to stimulate design and experimentation with real hardware and representative software in courses where mobile robotics is adopted as a motivating platform to introduce mechatronics competencies. Basic LabVIEW examples are proposed for three case-study laboratory practices. These are implemented with the NXT Toolkit and the NXT Direct Command programming libraries for standalone and remote execution, respectively. The application of this instructional material has been tested in two different experiences with senior undergraduate engineering students. A description of the courses as well as an assessment of student results are also included.

Using LEGO NXT Mobile Robots With LabVIEW for Undergraduate Courses on Mechatronics

Design-based learning (DBL) is an educational approach grounded in the processes of inquiry and reasoning towards generating innovative artifacts, systems and solutions. The approach is well characterized in the context of learning natural sciences in secondary education. Less is known, however, of its characteristics in the context of higher engineering education. The purpose of this review study is to identify key characteristics of DBL in higher engineering education. From the tenets of engineering design practices and higher engineering education contexts we identified four relevant dimensions for organizing these characteristics: the project characteristics, the role of the teacher, the assessment methods, and the social context. Drawing on these four dimensions, we systematically reviewed the state-of-the-art empirical literature on DBL or DBL-like educational projects in higher engineering education. Based on this review we conclude that DBL projects consist of open-ended, hands-on, authentic and multidisciplinary design tasks resembling the community of engineering professionals. Teachers facilitate both the process of gaining domain-specific knowledge and the thinking activities relevant to propose innovative solutions. Teachers scaffold students in the development from novice to expert engineers. Assessment is characterized by formative and summative of both individual and team products and processes and by the use of a variety of assessment instruments. Finally, the social context of DBL projects includes peer-to-peer collaboration in which students work in teams. The implications of these findings for further research on DBL in higher engineering education are discussed.

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A sampled literature review of design-based learning approaches: a search for key characteristics

Bearing damage is the most common failure in electrical machines. It can be detected by vibration analysis. However, this diagnosis method is costly or not always accessible due to the location of the equipment and the choice of the implemented sensors. An alternative method is provided with the electrical monitoring using the stator current of the electrical machine. This study aims at developing a diagnostic system based on the current feature generated by a frequency selection in the stator current spectrum. The features are evaluated by means of the linear discriminant analysis and the fault diagnosis is performed with the Bayes classifier. The proposed method is evaluated by two types of damages at different load cases. The results show that the damaged bearings can be distinguished from the healthy bearing depending on the considered load cases.

Fault Diagnosis of Bearing Damage by Means of the Linear Discriminant Analysis of Stator Current Features From the Frequency Selection

In today's teaching and learning approaches for first-semester students, practical courses more and more often complement traditional theoretical lectures. This practical element allows an early insight into the real world of engineering, augments student motivation, and enables students to acquire soft skills early. This paper describes a new freshman introduction course into practical engineering, which has been established within the Bachelor of Science curriculum of Electrical Engineering and Information Technology of RWTH Aachen University, Germany. The course is organized as an eight-day, full-time block laboratory for over 300 freshman students, who were supervised by more than 60 tutors from 23 institutes of the Electrical Engineering Department. Based on a threefold learning concept comprising mathematical methods, MATLAB programming, and practical engineering, the students were required to transfer mathematical basics to algorithms in MATLAB in order to control LEGO Mindstorms robots. Toward this end, a new toolbox, called the ?RWTH-Mindstorms NXT Toolbox,? was developed, which enables the robots to be controlled remotely via MATLAB from a host computer. This paper describes how the laboratory course is organized and how it induces students to think as actual engineers would in solving real-world tasks with limited resources. Evaluation results show that the project improves the students' MATLAB programming skills, enhances motivation, and enables a peer learning process.

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MATLAB Meets LEGO Mindstorms—A Freshman Introduction Course Into Practical Engineering

For the description of a permanent magnet excited synchronous machine the idealized equations of common synchronous machines can be used omitting the damping windings and replacing the current excitation by a permanent flux. For a more accurate modeling, nonideal behavior like saturation, cross-coupling magnetization and slotting effects can be included. This is done by extending the common d-q equations by additional elements. This also includes the time dependent variations of the parameters causing additional induced voltages especially at high currents and speed. The elements of the extended equations are extracted from a finite element analysis of the device under test. The derivation of the equations and a simulation of a permanent magnet excited synchronous machine with the applied theory are presented.

Extension of a d-q model of a permanent magnet excited synchronous machine by including saturation, cross-coupling and slotting effects

Within this paper a methodology for the assessment of energy and resource consumption within manufacturing processes is described and two case studies from the automotive sector were evaluated. On basis of the Life Cycle Assessment approach the energy and material flows within single manufacturing processes were acquired concerning the two selected case studies. With the generated knowledge about energy and material use it was possible to show up optimisation potentials for the reduction of the ecological impact of the determined products within the manufacturing phase. The work shown in the paper was conducted within the project BEAT which is kindly financed by the Federal Ministry of Education and Research in Germany (BMBF).

Assessment of Energy and Resource Consumption of Processes and Process Chains within the Automotive Sector

In the development process of electrical drive trains, consisting of a motor, the power electronics and the control scheme, it is difficult to predict the exact machine and control behavior in combination with the converter. Therefore, system simulations with analytical machine models embedded in a circuit simulation environment are performed. In order to increase accuracy by paying attention to parasitic machine effects caused by e.g. saturation or slot harmonics, a Finite Element model can be used instead of the analytical machine model. In this paper such a field-circuit coupling is applied to the simulation of a permanent magnet synchronous machine servo drive and the results are shown and discussed.

System simulation of a PMSM servo drive using the field-circuit coupling

Verfahren zur Montage von Blechen 5 auf einer Welle 1 eines fur eine elektrische Maschine vorgesehenen Rotors, wobei die Bleche 5 auf der Welle 1 gleitend aufgeschoben und zwischen zwei mit der Welle 1 drehfest verbundenen Druckscheiben 4, 6 eingespannt werden, wobei die Bleche 5 auf die Welle 1 aufgeschoben werden und gegen einen Anschlag 4 anliegen, der von einer in einem ersten Teilabschnitt 2 der Welle 1 angeordneten ersten Druckscheibe 4 gebildet wird, wobei die zweite Druckscheibe 6 unter axialer Verspannung der Bleche 5 auf einen zweiten axialen Teilabschnitt 3 der Welle 1 kraftformschlussig aufgepresst wird, nachdem die Oberflache des zweiten axialen Teilabschnittes 3 zuvor durch Einbringung eines Ausenoberflachenprofils aufgeweitet wurde.

Thomas Herold

Papers

MATLAB Meets LEGO Mindstorms—A Freshman Introduction Course Into Practical Engineering

Extension of a d-q model of a permanent magnet excited synchronous machine by including saturation, cross-coupling and slotting effects

Assessment of Energy and Resource Consumption of Processes and Process Chains within the Automotive Sector

System simulation of a PMSM servo drive using the field-circuit coupling

Rotorwelle mit Blechpaket