For dynamic car simulators, it is obvious that the longitudinal motion cannot be fully reproduced, the possibility to simulate longitudinal motions being generally reduced to less than 1m. In our case, a four post shaker is intended to be built as dynamic car simulator. Each post shaker, one under each car wheel, is aimed to generate mainly vertical vibrations and lateral motion. Since the displacements/motion in the longitudinal direction can only be partially reproduced, our problem was how to compensate the impossibility of fully reproducing the longitudinal motion by at least taking into account the influence of the longitudinal motion on the vertical vibrations. In this paper a simplified 4 DOF “bicycle” model is used for vertical dynamics, instead of a 7 DOF full car vertical dynamics model, which will be considered in a further study. On the other hand, the vertical vibrations are different for the same car riding on the same road, but for different acceleration regimes: 1) null acceleration (e.g., 60km/h constant speed); 2) uniform acceleration from 10 to 110 km/h (during 8 seconds), followed by uniform deceleration from 110 to 10 km/h (during another 8 sec), then uniform acceleration from 10 to 60 km/h (during the last 4 sec of the simulation). In order to reproduce in the dynamic car simulator the vertical vibrations of the above-mentioned longitudinal motion regimes (involving displacements of tens of meters), the following steps are proposed: a) direct dynamics CARSIM computer simulations of the car motion and its interaction with the road; b) inverse dynamics of car vertical model (4 degrees of freedom), using as input the following parameters computed in step a): the vertical displacements and velocities of the sprung mass and of the front and rear wheel centers as well as the pitch angle of the sprung mass and its rate. These inverse dynamics computer simulations are performed using an in-house Matlab software programming only the 4-DOF vertical car/road interaction (2D “bicycle” model in the pitch plane, no roll motion considered), without considering any longitudinal motion. The output of these inverse dynamics computer simulations, using the in-house Matlab software, is the “modified/distorted road profile”. Thus, the modifications brought to the real road profile are aimed to compensate the lack of the longitudinal degree of freedom in the dynamic car simulator, in order to reproduce the vertical vibrations of the above-mentioned longitudinal motion regimes (so that to encounter the same car vertical displacements and accelerations for the in-house Matlab simulation, as for the CARSIM simulation). Results are presented in order to show how the real road profile is modified/distorted in order to cope with this impossibility to simulate the road profile in dynamic car simulators, without huge costs.

Todays’ product development process is characterized by an increasing use of embedded software solutions integrated into mechatronic products. The development is more and more translocated into a virtual environment. New software methods and tools have to be developed. Industry 4.0 is an approach to highlight the tendency of modern development. Communication between smart products, communication via internet technologies, cyber-physical systems and the Internet of Things are the basis of Industry 4.0. Owing this development, used project management methodologies have to be adjusted. In special the well-known V-Model is now extended to the W-Model to cope with the new requirements like communications between different disciplines. New approaches in virtual development have to be adapted to modern teaching techniques. Therefore a course for first semester mechanical engineering students is conducted by the department of Computer Integrated Design at the Technische Universität Darmstadt. Industry 4.0 fundamentals are taught as well as the development process underlying the so called W-Model. The students will apply this knowledge while they participate in exercises. A web-based tutorial is provided every week with different learning packages. With these learning packages, the students learn to use the project management techniques as well as software development techniques to solve different tasks. Later complex data structures and algorithms can be coded and are applied. The software development techniques, established in development of information technologies, gets more important in mechanical engineering. Therefore the students learn these aspects. Over three months length the students work in groups and use all their skills to realize a bigger software-project — a digital factory. They use a virtual testing environment (ViTMeS 3.0) to develop their solution. The presented ViTMeS 3.0 is a further development of a virtual testing environment used in last year’s team work. Later they can test their code with a real life example. This example, the digital factory, built with LEGO Mindstorms, is an important part of teaching students the foundations of communication and information techniques as well as software development and programming skills. The last step of the team work is the coding of a graphical user interface for appropriate visualization.

In the last decade, the service sector had a very rapid growth, due to the so-called “tertiarisation” of the economy. Accordingly, the energy consumption, mainly attributable to public and private buildings, is rapidly growing, thus making buildings energy saving one of the main issues of the energy policy at regional, national and international levels. To this aim, we developed an effective methodology to improve energy efficiency of the service sector buildings. This may represent a handy great opportunity to save natural and economic resources, especially where the buildings structure and the technical systems are old, the maintenance activities are not carefully carried out or a systematic energy management is not applied. Nevertheless, actions in this direction are often considered too expensive and complicated, if compared with residential energy optimization, because of the big extension, the variety of activities and the high number of occupants typical of the service sector buildings. The developed approach for energy audits aims to investigate the energy aspects of existing non-domestic buildings in a structured way, in order to clearly identify their energy saving potential and to improve their energy performances. The main goal of the study is defining a general methodology to analyze the current energy use and consumption considering a limited number of their peculiar elements such as dimensions, activities, users behavior, technical systems data and energy bills. Furthermore, these informations are completed by an appropriate energy measuring campaign. All the possible energy uses in service buildings are taken into account (i.e. lighting, ventilation, air conditioning, hot water production). The results obtained from the analysis allow to evaluate a global level of building energy efficiency, and to identify those single areas, specific systems or everyday activities where energy is wasted. These considerations also provide basis for programming cost-effective energy saving action plans. The effectiveness of the proposed methodology is demonstrated through a case study for an Administrative Center building in Rome, Italy. Results demonstrate the methodology reliability and the cost reduction potentialities.

Welding is one of the most important joining techniques used in the metalworking industries. In order to exploit efficiency potentials to a maximum possible extent, robot systems are adopted to automate the welding process whenever possible. This has become standard for high volume manufacturers like the automotive industry where thousands or millions of products are manufactured in the same or a very similar way. There is, however, a large obstacle for using automated welding robots in industries with highly individualized products: The programming effort for robot systems very often exceeds the manual welding times due to small lot sizes. Therefore this paper proposes an approach to automatically derive welding programs. The building blocks of this technique are an automatic identification of feasible candidate weld joints from a CAD model, a knowledge base and a weld program compiler. After verification of these joints by a design engineer the machine instructions for the robot system have to be derived. Therefore the proposed approach defines the necessary structures of a Welding Expert Knowledge Base (WKB) where the relevant knowledge of a welding engineer designer is modeled in terms of rules of fuzzy rule sets. On top of the WKB we propose a weld program compiler which automatically identifies the sequence of weld joints and the necessary number of welding passes, generates optimized tool paths and finally derives appropriate parameter settings.

The increasing engineering accreditation program requirements for outcome based assessment, combined with emphasis on green energy and other sustainable technologies, prompted introduction of a solar panel tracking project within a senior product design course. Recognizing that the course is offered to students with mechanical engineering as well as software engineering (mechatronics) backgrounds, technical aspects emphasized three dimensional Computer Aided Design (CAD), rapid prototyping, and basic microcontroller interface electronics and programming. Mixed teams including students from both backgrounds were mandatory. This paper reports observations after three course offerings. In particular, it is noted that a paradigm shift away from lectures to hands-on development laboratories is needed, but formal laboratory milestones and submission deadlines remain essential for successful team project completion.

Composing of models and simulation of statics, steady state conditions and dynamic responses of an electro-hydraulic servovalve is considered in the paper. The observed servovalve contains an electro-mechanical transducer (as a torque motor), a nozzle-and-flapper valve and a sliding spool in sleeve with elastic position feedback from spool to flapper. For composing mathematical models of the servovalve multi-pole models of functional elements are used. For representing relations between inner variables oriented graphs are used. Results of the current work will be used in modeling and simulation of electro-hydraulic servo-systems.

The work points to study the effects of bodies flexibility concerning the Running Dynamics and Structural requirements and how such aspects could be integrated into a single design process of a mass transit vehicle in terms of Comfort, Safety, Track fatigue and Bogie-frame design. The multi-body system of the vehicle has been developed. The finite element model of the flexible bodies as car-body, wheel-set, bolster-beam and bogie-frame have been implemented. The critical but necessary step, in the integration process of the flexible body into a multi-body system, is the reduction of the finite element model of the body. For that reason an analytical verification in focused to validate the reduced FE-model with respect to the full FE-model has been thought, developed and implemented to provide a useful design tool; such an analytical verification aids the engineer to control and to optimize the reduction technique applied to the full-FE-model of the body. The validation procedure, which has been implemented, consists in developing an alter for the DMAP, Direct Matrix Abstraction Program of the FE-solver, and processing the output into a programming environment.

This investigation intends to establish an experimental test platform for a small vertical-axis wind turbine (VAWT), which is installed on the rooftop of a building. The experiment platform designed here is flexible and suitable for executing the systematic performance evaluation on different types of VAWT. By utilizing the data acquisition system (DAQ), all environmental information and power data from sensors and generator on the platform are recorded and transferred to the computer automatically. Later, these analogy signals are transformed to digital format for transmitting into computer. Also, with the aids of a visual software programming within the framework of Labview, the real-time monitoring on the input/output parameters of generator and the wind condition on the rooftop can be accomplished simultaneously. Afterwards, the data processing and in-depth analysis on the experimental outcomes are carried out via the established computer program. Consequently, the on-site performance of the wind turbine generator system is attained in an automatic and systematic manner. Moreover, to ensure for providing sufficient data and its accuracy, statistic concept is enforced to judge whether the test data are qualified or not in the data-processing procedure. Regarding the safety evaluation on this test platform, the numerical models of the wind turbine and platform are analyzed numerically via ANSYS Workbench to obtain the force exerting on the main shaft and blades. This force distribution can be analyzed for checking if they can stand and meet the safety criterion under various wind speeds. In summary, together with the data-acquisition software programmed under the framework of Labview, this experimental system can provide the capability for monitoring, recording, and filtering these test data in an rigor manner, and is appropriate for executing the R&D and performance evaluation on different VAWTs.

In the present paper the new wind tunnel located in the Fluid-dynamic Laboratory of the Dipartimento di Ingegneria Meccanica e Gestionale (DIMeG) of the Bari Polytechnic will be shortly described and the first experimental measurements on a vertical axis wind turbine (VAWT) will be shown. The DIMeG wind tunnel has been designed by the research group on wind energy of the Department. It is a subsonic, closed loop, wind tunnel with a transparent test part where small scale models can be analyzed. A four bladed axial fan is driven by an asynchronous three phase electric motor, which is connected to an inverter in order to change the wind speed. Angular blades have been inserted at the two curves between the fan and the test section in order to increase the uniformity of the velocity profile after the two curves. An optimization fluid-dynamic study has been carried out in order to find the best blade profile. A honeycomb has been also inserted upstream the test section in order to destroy the still existing small vorticity generated by the fan and the curves. A three-axis traversing, called Cartesian robot, has been designed and built above the test section, in order to move the hot wire probe, for wind speed measurements, by means of four step by step electric motors controlled by a personal computer. A data acquisition system has been set up. All the principal commands and controls can be performed by a dedicated personal computer, which has been programmed using LabVIEW ® G-programming language. The first experimental activity has been performed on a VAWT model, of the Giromill type with parallel blades. The turbine has been connected to an AC brushless servo, able to control the braking torque. Experimental results of the flow field in two horizontal planes have been set up using a two component hot wire probe (Dantec 55R51) calibrated with the manual system Dantec 54H10. The measurement grid adopted is formed by 20 nodes in the Y direction (main flow direction) and 10 nodes in the X direction.

This paper describes a computational framework for automatically synthesizing planning logic for unmanned surface vehicles (USVs). The basic idea behind our approach is as follows. The USV explores the virtual environment by randomly trying different moves. USV moves are simulated in the virtual environment and evaluated based on their ability to make progress towards the mission goal. If a successful action is identified as a part of the random exploration, then this action is integrated into the logic driving the USV. This approach has been utilized for automatically generating planning logic for USVs. The planning logic is represented as a decision tree which consists of high-level controllers as building blocks, conditionals and other program constructs. We used strongly-typed GP-based evolutionary framework for automatic generation of planning logic for blocking the advancement of a computer-driven intruder boat toward a valuable target. Our results show that a genetic programming based synthesis framework is capable of generating decision trees expressing useful logic for blocking the advancements of an enemy boat.

Three axis serial robots with different sizes are widely used for pick and place, welding and various operations in industry. Developments in mechatronics, which is the synergistic integration of mechanism, electronics and computer control to achieve a functional system, offer effective solutions for the design of such robots. The mechatronic design process involves solid modeling, assembly, rigid body dynamics, finite element rigidity analysis, motion control and computer programming. In this study, SolidWorks, CosmosMotion, CosmosWorks and PC-based motion control programs are used with an integrated approach. The integration software is developed in VisualBASIC by using the application programming interface (API) capabilities of these programs. An experimental three axis serial robot with a reach distance of 790 mm has been produced to develop and test the process.

In this work, a robotic painting task is addressed in order to automate and improve the efficiency of the process. Usually, path planning in robotic painting is done through self learning programming. Recently, different automated and semi-automated systems have been developed in order to avoid this procedure by using a CAD-drawing to create a CAD-guided trajectory for the paint gun, or by acquiring and recognizing the overall shape of the object to be painted within a library of prestored shapes with associated pre-defined paths. However, a general solution is still lacking, which enables one to overcome the need for a CAD-drawing and to deal with any kind of shapes. In this paper, graph theory and operative research techniques are applied to provide a general and optimal solution of the path planning problem for painting robots. The object to be painted is partitioned into primitives that can be represented by a graph. The Chinese Postman algorithm is then run on the graph in order to obtain a minimum length path covering all the arcs (Eulerian path). However, this path is not always optimal with respect to the constraints imposed by the painting process, hence dedicated algorithms have been developed in order to generate the optimal path in such cases. Based on the optimal path, the robot trajectories are planned by imposing a constant velocity motion of the spray gun, in order to ensure a uniform distribution of the paint over the object surface. The proposed system for optimal path planning has been implemented in a Matlab environment and extensively tested with excellent results in terms of time, costs and usability.

The aim of this study is to investigate the capability of the micropolar peridynamic theory to analyze elastic behavior of plates with various length and width. Since the quantities such as stress and strain are related to displacement field, only the displacement fields of these structures are computed using the micropolar peridynamic model while Poisson’s ratios are kept constant. The results are compared both to the analytical solution of the classical elasticity theory and to the solution of displacement based finite element methods. The software package ANSYS is used for FEM results. To compute the displacement field, a programming code is developed using MATHEMATICA. In the peridynamic theory the constitutive model contains only central forces and can be applied only to the materials having 1/4 Poisson’s ratio. It is the biggest shortcoming of the peridynamic theory. To overcome strict Poisson’s ratio limitation of the peridynamic theory, the micropolar peridynamic theory is proposed. The micropolar peridynamic model allows peridynamic moments, in addition to peridynamic central forces, to interact with the particles inside the material horizon. The introduction of the moments to the theory allows us to deal with the materials having Poisson’s ratio different from 1/4. This modification can be seen as the generalization of the peridynamic theory. Furthermore, the micropolar peridynamic theory can be easily implemented using the finite element methods. This provides easy application of the boundary conditions to the physical model in hand. In this work, by applying the micropolar peridynamic theory, we observed that the displacement fields of the plates are strongly affected by dimensional ratio of the plates. However, it is naturally expected that the micropolar and classical theories should give the same results, at least to a certain extend. This strong dependability on the dimensions of the structure can be a significant shortcoming of the micropolar peridynamic theory.

For a statically indeterminate structure we examine the class of internal forces that are in equilibrium with a given external loading f. We define the optimal stress φ opt as the smallest possible magnitude of any equilibrating internal force distribution. The stress sensitivity k = max f { φ f opt /‖ f ‖} , a purely geometric property of structure, is a measure of the sensitivity of the structure to variable external loading. Using the result for optimal stresses, an expression for the stress sensitivity factor is obtained in terms of the structure’s kinematic interpolation mapping. These notions, the corresponding theoretical results, and a simple implementation to finite element models are presented using linear and conic programming.

This paper summarizes the activities, contents and overall outcomes of our experiences with international project teams working with different engineering projects, in particular the Interdisciplinary Project on fourth semester (TVP4E). The TVP4E course combines the theory and practical design of small autonomous robots. The theoretical part includes mathematical modeling, system dynamics, control theory, digital and analogue electronics, and microprocessors. The practical project is to design an autonomous robot performing two tasks: compulsory task decided by the teachers and the free task decided by students. The success of this particular fourth semester project inspired us to start other international project semesters. Globalization makes it necessary to cooperate on an international platform. A great contributor to globalization is the student mobility program within the EU, like the Socrates-Erasmus program. At the Copenhagen University College of Engineering we have more then 50 active Socrates-Erasmus agreements. Beside that we have bilateral agreements with many non-European countries. Usually the exchange students come to us after 2–3 years of studying in their home countries. Their prerequisites are in most cases the basics of mathematics and physics, but there is very big variety in their practical skills, like electronics and programming. Some of them do not have much experience in working with projects. The challenge of supervising the international teams is to motivate the students with different prerequisites to study the theory and work together with other students from very different cultures with a practical engineering project. In conclusion we describe the benefits from this program to all of us: students, teachers and the universities.

Mechanical touch probes on CMMs (Coordinate Measuring Machines) are the most common sensors used for blade inspection. Most Blade Measurements today are based on a mechanical probe. The amount of useful data that can be collected using the mechanical touch probe is limited. Since blades are characterized by complicated free form 3D geometry shapes, the traditional solution of touch trigger probes on a CMM is very limited both in hardware as well as in measurement software. One of the major challenges of blade measurement is the “blade alignment” — finding the blade position relative to the CMM and moving the coordinate system from the CMM to the blade. It is a tricky trail and error approach, unless one is using very high precision (and very expensive) mechanical jigs. The recent trend from the touch trigger probe to a mechanical (Analog) scanning probe is a step in the right direction, in terms of data collection rate; however it is still limited by some major fundamental characteristics of the mechanical analog sensor: a. A mechanical probe needs to maintain continuous contact with the surface and thus is limited in its scanning speed. b. By nature, the dynamic range of a mechanical probe is only a few hundred microns, which makes the scanning pattern, the alignment routine and the programming of the scan path more complicated. c. Programming a mechanical probe for a cross-section scanning operation requires operator skill and experience. d. The resolution and size of the features that can be scanned are limited by the diameter of the stylus, so features such as leading and trailing edges are not good candidates for any mechanical or analog probe measurements.

Nb doped barium titanate (BT) experiences unique phenomena over a range of dopant concentrations. One important phenomenon is the resistivity behavior as a function of donor concentration. The role of the grains and the grain boundaries in this system is not fully established yet. There are diverse opinions on this subject, since this system is usually only in partial equilibrium and hence very complex. We examine the system using Impedance Spectroscopy (IS). Two new analysis methods for IS based on evolutionary programming techniques, which are inspired by biological evolution, have been developed in our lab. Those evolutionary programming techniques are called Genetic Programming (GP) and Genetic Algorithm (GA). This is an approach to solve (or in the case of GA suggest solution for) such ill-posed inverse problems. By implementation and improvement of the use of those techniques for analyzing IS results, we believe that the role of the grains and the grain boundaries can be separated and the physical processes occur can be analyzed.

This paper describes a new algorithm for automatically reverse-engineering symbolic analytical models of dynamical systems directly from experimental observations, for the purpose of modeling, control and exploratory analysis. The new algorithm builds on genetic programming techniques used in symbolic regression to infer differential equations from time series data. We introduce the core algorithm for building coherent mathematical models efficiently and then describe its application to system identification. The method is demonstrated on a number of nonlinear mechanical and biological systems.

Tool management functions cover tool system elements for assembly, operating conditions for process planning and NC programming, tuning operation execution on the machine, calculation of remaining tool life for planning tool changes, number of tools in stock, supplier terms for ordering and average utilization of tools over time for production planning. A database system was constructed catering for network access by being written as a web application. The system’s practical use is demonstrated by several typical scenarios of use.

Field-Programmable Gate Array (FPGA) technology has been applied widely in electronic engineering and computing industries, but it has not had the same level of reception in other disciplines including mechanical engineering [1]. The purpose of this paper is to examine FPGA implementations of signal processing techniques that are used in the context of bearing condition monitoring. As the number of bearings can be large sparse sensor arrays are used to locate and detect their condition. The demands of realtime process monitoring [2] [3] can place a heavy burden upon the monitoring system. Field-Programmable Gate Array (FPGA) technology [4] in this application makes it possible to implement more sophisticated algorithms. These exploit its high-speed, parallel, reconfigurable architecture. Bring forth the advantages of FPGA technology to condition monitoring. The techniques covered are: cross-correlation, digital signal processing (DSP) Infinite Impulse Response (IIR) filters, neural networks and signature matching. The implemented designs are optimised for both execution time and the amount of logic area consumed. Results were obtained from each technique and were assessed and compared in terms of execution time and also the amount of logic consumed on the FPGA. Over the past 15 years FPGA technology has been applied extensively in electronic engineering but its scope has not been as vastly in mechanical engineering. The objective of this paper was to examine an application in mechanical engineering. Ideally this would be done with a mechanical engineering compatible approach, giving rise to a methodology, which would allow FPGA programming [5] to become a transferable skill.