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  • 1. Bathelt, Jens
    et al.
    Jönsson, Anders
    How to Implement the Virtual Machine Concept Using xPC Target2003Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents an overview of the historical background of the virtual machine, containing a real control, a machine simulation and a 3D machine visualisation. This setup enables realistic system simulations, since the simulation input comes from a real control. The first known implementation of the virtual machine using xPC Target is described with an existing water jet cutting machine as an example. MathWorks products offer all necessary software for the presented setup, except the interface for the actual speed value from the simulated incremental encoder to the control. The unique xPC driver implementation, as a noninlined C-MEX S-Function, is presented at the end of this paper. The successful implementation of the virtual machine demonstrates the feasibility of the presented approach.

  • 2. Bathelt, Jens
    et al.
    Jönsson, Anders
    Bacs, Christian
    Kunz, Andreas
    Meier, Markus
    Conceptual Design Approach For Mechatronic Systems Controlled by a Programmable Logic Controller (PLC)2003Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Traditionally, the development of mechatronic systems starts with the mechanical design. Later electronic components and program logic for the product are added. This work proposes an improved interdisciplinary concurrent product development process with an enhanced function structure for the conceptual design phase. The new methodology is based on the German guideline VDI 2221 [1]. Transition conditions, time aspects and logic flow are added to the normal function structure. An example shows how to use the improved function structure. The enhanced function structure is used to derive the initial logic for the development of the PLC program controlling the machine later on. Since the extended function structure also covers the traditional information, it can still be used when building the assembly tree. By adding more information in the neutral function structure, the same information can be used for the mechanical design as well as for the electronic and logical design. The interdisciplinary communication and documentation among the engineers will be improved and errors in the concept will be detected earlier.

  • 3. Bathelt, Jens
    et al.
    Jönsson, Anders
    Bacs, Christian
    Meier, Markus
    Modularisierung SPS-gesteuerter mechatronischer Systeme2003Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Rein mechanische Lösungen werden zunehmend von mechatronischen Systemen abgelöst. Der X-by-wire Ansatz zeigt auch, dass der Anteil an mechanischen Teillösungen eines mechatronischen Systems immer weiter zurückgeht. Der vorliegende Beitrag skizziert einen Entwicklungsprozess für SPS-gesteuerte mechatronische Systeme, der dem immer wichtiger werdenden Steuerungsanteil Rechnung trägt. Dabei steht das parallele Arbeiten der Steuerungstechnik und der Konstruktion im Vordergrund, um die Entwicklungszeiten zu verkürzen und Fehler früher zu erkennen. Realisiert wird dies durch eine fachspezifische Modularisierung, deren erste Modulhierarchie als Ausgangslage der jeweiligen Disziplinen fungiert und somit einen parallelen Start ermöglicht. In dieser Arbeit werden Regeln vorgestellt, um die fachspezifischen Module von einer Funktionsstruktur abzuleiten. Abschliessend wird das Vorgehen anhand eines Industriebeispieles erläutert.

  • 4. Broman, Göran
    et al.
    Hermann, Madeleine
    Jönsson, Anders
    Modelling Bellows Expansion Joints by Standard Beam Finite Elements2000Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A procedure for modelling bellows expansion joints by the standard beam finite elements of I-DEAS Master Series 6 is presented. It is shown that the bellows dynamic behaviour can be modelled by beam elements by manipulating certain element parameters. The method will work in any software in which these parameters can be set by the user. Compared to a shell elements model the model size is reduced by at least a factor of 100. This is especially advantageous when the bellows is only a part of a system to be optimised with respect to overall design parameters. In comparison to existing "semi-analytical" methods the beam finite elements have the advantages of considering axial, bending and torsion degrees of freedom simultaneously and that the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements, is easily facilitated. The procedure is verified by experimental results from other investigators.

  • 5.
    Broman, Göran
    et al.
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Hermann, Madeleine
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Jönsson, Anders
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Modelling Flexible Bellows by Standard Beam Finite Elements1999Rapport (Annet vitenskapelig)
    Abstract [en]

    A procedure for modelling flexible metal bellows by the standard beam finite elements in I-DEAS Master Series 6 is presented. In spite of the geometry of the bellows being far from a beam, it is shown that the bellows dynamic behaviour can be modelled by beam elements with the suggested procedure. The model size is reduced by a factor of 100-1000 compared to a shell elements model. This is especially advantageous when the bellows is only a part of for example an exhaust system to be optimised with respect to overall design parameters. In comparison to existing "semi-analytical" methods the standard beam finite elements have the advantages that axial, bending and torsion degrees of freedom are included simultaneously and that the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements, is easily facilitated. The procedure is verified by experimental results from other investigators.

  • 6. Broman, Göran
    et al.
    Jönsson, Anders
    The Nonlinear Behavior of a Rammer Soil Compactor Machine2000Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A theoretical model of a rammer compactor machine is described and its dynamic behaviour is analysed. The differential equations of the model are solved numerically by using standard software. Simulation results are presented as time series, phase plane diagrams, mappings and bifurcation diagrams. The results show that the system is highly nonlinear and indicates that harmonic, subharmonic and chaotic behaviour is present for the parameter variations used. This parameter sensitivity emphasizes the need for this kind of simulations in the product development process.

  • 7. Broman, Göran
    et al.
    Jönsson, Anders
    Hermann, Madeleine
    Determining Dynamic Characteristics of Bellows by Manipulated Beam Finite Elements of Commercial Software2000Inngår i: International Journal of Pressure Vessels and Piping, ISSN 0308-0161, E-ISSN 1879-3541, Vol. 77, nr 8, s. 445-453Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A procedure for determining dynamic characteristics of bellows by manipulating certain parameters of the beam finite elements of I-DEAS Master Series 6 is presented. The method will work in any software in which these parameters can be set by the user. Compared to a shell elements model the model size is reduced by at least a factor of 100. This is especially advantageous when the bellows is only a part of a system to be optimised with respect to overall design parameters. Stress in the bellows cannot be predicted by this method, but when the dynamic behaviour is known it can be used as input for stress calculations, if desired. In contrast to existing "semi-analytical" methods this method has the potential of considering axial, bending and torsion degrees of freedom simultaneously, and it facilitates the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements. The procedure is verified by experimental results from other investigators.

  • 8. Broman, Göran
    et al.
    Jönsson, Anders
    Wall, Johan
    Englund, Thomas
    Introductory Optimisation Study of a Rammer Soil Compactor Machine2001Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Rammer compactor machines perform dynamic soil compaction. The complexity of this machine type makes design optimisation through traditional prototype testing impractical. This has pointed to the need for a theoretical model and simulation procedure for prediction of the dynamic behaviour of the machine and a procedure for optimisation as design parameters are changed during product development. In this paper a theoretical model of the rammer machine in combination with a soil model is described. This multi-body dynamics system is solved numerically. The system is non-linear and chaotic behaviour is possible. This parameter sensitivity emphasises the need for this kind of simulations in the product development process. A fairly regular behaviour is necessary for a predictable and safe operation. Parameter combinations giving too irregular behaviour are non-feasible. The energy transfer rate from the rammer machine into the soil is used as the objective function for optimisation. Multi-start Sequential Quadratic Programming for optimum search is used. To cover the design space well a Uniform Experimental Design is used for selection of starting points. This procedure proves to work well for the problem of this introductory study. The study shows a significant potential for improved compaction capacity although considering only the three design parameters that are most easily changed in practice. Approximately the same optimum is obtained both for operation on soft soil and hard soil, so a good all-round design seems possible. Including this theoretical support in the product development process should make it much more effective in finding optimum designs, also for other machines of similar type.

  • 9.
    Fredin, Johan
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Jönsson, Anders
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Broman, Göran
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Holistic methodology using computer simulation for optimisation of machine tools2012Inngår i: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 63, nr 1, s. 294-301Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Virtual machine concepts supporting optimisation of machine tools have been developed in earlier work. The virtual machine concept is a tool that can describe the behaviour of a machine tool while considering the interaction between mechanics of the machines and the control system. Considerable amount of work has been done proving the concept and showing the potential of such a design tool in different contexts. Several studies have shown the potential of using the virtual machine concept, although, no work has been found that is exploring the potential of a full optimisation study. The aim of this work is to show the potential of the virtual machine concept in an optimisation study of the complete machine tool, including the mechanical system, parameters in the control system, the NC-code as well as choice of servo and drive systems. An efficient optimisation strategy is presented, making it possible to solve the complex optimisation problem within a reasonable amount of time. A combination of optimisation algorithms is used to achieve a fast and accurate way of solving the complex task to optimise the complete machine tool. Genetic algorithms, gradient based algorithms and more traditional hands on engineering are used for solving the optimisation problem. Post processing and data mining is suggested as a way of extracting as much information as possible from optimisation results with the aim to increase the knowledge about the studied system. An important conclusion is that the virtual machine should support the decision making in product development, not replace the product developers as regards decision making.

  • 10. Jönsson, Anders
    Lean Prototyping of Multi-body and Mechatronic Systems2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Major drivers behind increased efforts in product development are the increased competition due to globalisation and the urgent transformation of society towards sustainability. Furthermore, the average product lifetime has been compressed significantly over the last decade. Due to these trends, there is increasing demand for an efficient product development process. Cutting time-to-market, reducing costs and increasing quality are widely accepted as key factors to successful product development. Consideration of sustainability aspects in product development is also becoming increasingly important. Methods and tools that are useful also for small and medium sized enterprises are of particular importance for the Swedish industry. This thesis suggests a definition of lean prototyping and points to its potential for supporting efficient product development. This is done through two case studies: a soil compactor machine treated as a multi-body system and a water jet cutting machine treated as a mechatronic system. Lean prototyping is defined as a coordinated approach to experimentation with the purpose of achieving cost-efficient and accurate enough prediction of product characteristics to support optimisation and well-informed design decisions during product development, especially in the early stages. This often involves an iterative search for and use of a suitable combination of virtual and limited physical prototypes as well as the reuse of knowledge from previous projects. The case studies are performed in cooperation with one small and one medium sized company, indicating the usefulness of the approach for different product types as well as for different company sizes. More specifically, the validated multi-body model of the soil compactor machine describes the dynamics of the machine satisfactorily and the optimisation study shows a significant potential for improved compaction capacity. This potential would not likely been found through traditional physical prototyping. The related comparative study of contact transition conditions is a contribution to consistent impact modelling in multi-body dynamics in general. The real-time virtual machine concept for simulation of the water jet cutting machine, including detailed mechanical component models, is unique. The fully automated concept implementation makes it a promising base for multidisciplinary design optimisation of the water jet cutting machine, and probably of mechatronic products in general.

  • 11. Jönsson, Anders
    Modelling, Simulation and Experimental Investigation of a Rammer Compactor Machine2001Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This licentiate thesis considers the modelling, simulation and experimental investigation of a rammer compactor machine. The purpose is to develop an efficient and verified method for simulation of rammer compactor machines to be used in the product development process. The experience gained through this work is also intended to be useful for studying other types of dynamic compactor machines. Rammer compactor machines perform impact soil compaction. This is more efficient than static compaction. The machines are often used in places where a high degree of compaction is needed, and where the space for operation is limited. The complexity of this type of machine makes design optimisation through traditional prototype testing impractical. This has pointed to the need for a theoretical model and simulation procedure for predicting the dynamic behaviour of the machine. To be useful for optimisation the theoretical model and simulation procedure must be verified. By concurrently working with theoretical modelling, simulations, experimental verifications, and optimisation an efficient analysis support for product development is achieved. This co-ordination works both ways in an iterative manner: experimental investigations are used to verify theoretical models and simulations; and theoretical models and simulations are used to design good experiments. This Complete Approach concept enables better decisions to be made earlier on in the development process, resulting in a decrease in time-to-market and improved quality. In this thesis, the Complete Approach concept is applied to a rammer soil compactor machine. An introductory iteration is described. The good agreement between theoretical and experimental results indicates that the theoretical model and simulation procedure should prove useful in introductory optimisation studies. The thesis discusses reasons for the remaining discrepancy and suggests improvements in both the theoretical model and the experimental set-up for future iterations.

  • 12. Jönsson, Anders
    et al.
    Bathelt, Jens
    Broman, Göran
    Interacting with real time simulations – virtual reality in industry applications2003Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Modern manufacturing machines are highly multidisciplinary, and with demands on short time-to-market, product development based on traditional prototype testing has become impractical. By using virtual models, it is possible to test large numbers of variants and optimise the product with the aid of a minimum of physical prototypes. Due to the immense development of software and hardware for simulation and visualisation it should today be possible also for small and medium sized enterprises to use methods that just few years ago were too expensive and complicated. There is however still a great need for building knowledge and compe-tence. This work is an early step in a project aiming at a virtual water jet cutting machine to be used by the industrial partner for optimisation during the development process. The possibility of performing real-time simulations of this machine in a virtual environment, using a normal PC and commercial software, will be in-vestigated. Initially strongly simplified models of the system components are used and the focus is on the overall system model and the interaction between the operator and the virtual machine. It is shown that real-time interaction is possible with this system and with the obtained flexibility of the overall virtual model it should be easy to include more realistic component models for improved accuracy in future work. Preliminary results indicate however that to include, for example, flexibility within the mechanic structure, component modelling will be delicate. These models must describe relevant characteristics accurately enough while still being computationally effective enough for real-time interaction and systems optimisation to be possible. This will probably be a challenge in the continuation of the project, even with an expected continued strong devel-opment of computer capacity.

  • 13. Jönsson, Anders
    et al.
    Broman, Göran
    Experimental Investigation of a Rammer Soil Compactor Machine on Linear Spring Foundation2001Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Rammer compactor machines perform impact soil compaction, which is very efficient compared to static compaction. They are often used in places where a high degree of compaction is needed and the space for operation is limited. The complexity of this machine type makes design optimisation through traditional prototype testing impractical. This has pointed to the need for a theoretical model and simulation procedure for prediction of the dynamic behaviour of the machine. To be useful for optimisation as design parameters are changed during product development the theoretical model and simulation procedure must be verified. By concurrently working with theoretical modelling, simulations, experimental verifications, and optimisation an efficient analysis support for product development is achieved. This co-ordination works both ways in an iterative manner. Experimental investigations are used to verify theoretical models and simulations. Theoretical models and simulations are used to design good experiments. This Complete Approach concept makes better decisions possible earlier in the development process, resulting in decreased time to market and improved quality. In this paper the Complete Approach concept is described. It is applied on a rammer soil compactor machine. An introductory iteration, with emphasis on the experimental part, is described. In the experimental set-up the rammer foot is attached to a linear spring foundation. This eliminates uncertainties related to soil modelling and makes a check of the model of the machine itself possible. The good agreement between theoretical and experimental results indicates that the theoretical model and simulation procedure should be useful for introductory optimisation studies. Reasons for the discrepancy are discussed and suggestions for improvements of both the theoretical model and the experimental set-up in coming iterations are given.

  • 14. Jönsson, Anders
    et al.
    Broman, Göran
    Bathelt, Jens
    Implications of modelling one-dimensional impact by using a spring and damper element2005Inngår i: Proceedings of the Institution of mechanical engineers. Proceedings part K, journal of multi-body dynamics, ISSN 1464-4193, E-ISSN 2041-3068, Vol. 219, nr 7, s. 299-305Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A spring and damper contact force element is often used for modelling impact in multi-body dynamics. The related condition for transition between contact and non-contact is, however, inconsistently implemented in the literature and commercial software. This comparative study aims to clarify the implications of four commonly used transition conditions. Principal differences are discussed and, by simulation of a typical system, it is shown that there are significant differences in the dynamics of the system depending on the different conditions. Two of them give unrealistic contact forces and should imply incorrect prediction of system dynamics in most applications. This suggests that it is important to review results obtained from using these conditions and to eliminate them from commercial software. A discussion of the two other conditions culminates in a recommendation.

  • 15. Jönsson, Anders
    et al.
    Broman, Göran
    Engström, Anders
    Modelling of a Soil Compaction Tamping Machine using Simulink1999Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A theoretical model for the dynamic behaviour of a soil compaction tamping machine is derived. The Matlab toolbox Simulink is used to solve the equations of motion. Simulink is used because it is possible to combine the kinetic model of the machine with a more complex FE-model. The theoretical model has been verified experimentally, where the soil compaction tamping machine was run on a simulated soil material. The agreement between the simulation and the experiment is very good, which implies that this simplified model of the machine can be used for a more complete study of the total system, including a more correct soil model.

  • 16. Jönsson, Anders
    et al.
    Broman, Göran
    Östholm, Stefan
    Multidisciplinary Simulation of Active Control of Machine-Tool Vibration in Turning2000Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The increasing computer power in modern manufacturing machines has given the possibility to integrate advanced computer based control systems. In this work a simulation model for active control of machine-tool vibration in turning operations is described. The model contains both the mechanical structure and the control system. The simulation is done with and without active control. The structure vibration is suppressed by simulating actuators. The simulation is done to get a first indication of the potentials of a proposed new tool holder design and to test the usability of such multidisciplinary simulations as a supporting tool for product development. The results show that it is possible to simulate the total system. The vibrations of the tool holder tip could be decreased significantly by using reasonable forces. The software used was found to be very user friendly and to be able to perform such coupled simulations in this way during product development must be considered to be a great advantage.

  • 17. Jönsson, Anders
    et al.
    Broman, Göran
    Östholm, Stefan
    Multidisciplinary Simulation of Active Control of Machine-Tool Vibration in Turning2000Inngår i: System and Control:Theory and Applications, ISSN 960-8052-11-4, s. 61-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increasing computer power in modern manufacturing machines has given the possibility to integrate advanced computer based control systems. In this work a simulation model for active control of machine-tool vibration in turning operations is described. The model contains both the mechanical structure and the control system. The simulation is done with and without active control. The structure vibration is suppressed by simulating actuators. The simulation is done to get a first indication of the potentials of a proposed new tool holder design and to test the usability of such multidisciplinary simulations as a supporting tool for product development. The results show that it is possible to simulate the total system. The vibrations of the tool holder tip could be decreased significantly by using reasonable forces. The software used was found to be very user friendly and to be able to perform such coupled simulations in this way during product development must be considered to be a great advantage.

  • 18. Jönsson, Anders
    et al.
    Wall, Johan
    Broman, Göran
    A Virtual Machine Concept for Real-Time Simulation of Machine Tool Dynamics2005Inngår i: International journal of machine tools & manufacture, ISSN 0890-6955, E-ISSN 1879-2170, Vol. 45, nr 7, s. 795-801Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When designing CNC machine tools it is important to consider the dynamics of the control, the electrical components and the mechanical structure of the machine simultaneously. This paper describes the structure and implementation of a concept for real-time simulation of such machine tools using a water jet cutting machine as an application. The concept includes a real control system, simulation models of the dynamics of the machine and a virtual reality model for visualisation. The real-time capability of the concept, including the simulation of electrical and rather detailed mechanical component models is proofed. The validation process indicates good agreement between simulation and measurement, but suggests further studies on servo motor, connection and flexibility modelling. However, already from the initial simulation results presented in this paper it can be concluded that the influence of structural flexibility on manufacturing accuracy is of importance at desired feeding rates and accelerations. The fully automated implementation developed in this work is a promising base for dealing with this trade-off between productivity and accuracy of the manufacturing process through multidisciplinary optimisation.

  • 19. Stålhandske, Christina
    et al.
    Persson, Kent
    Lang, Maria
    Jönsson, Anders
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Fluid jet polishing of planar flat glass surfaces and within holes2014Inngår i: European Journal of Glass Science and Technology. Part A: Glass Technology, ISSN 1753-3546, Vol. 55, nr 2, s. 49-54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Planar ground float glass surfaces and the surfaces within holes are polished using fluid jet polishing (FJP) in order to improve their visual appearance or material strength. The large flexibility of FJP makes it suitable for polishing holes and other complex geometries. The influence of polishing speed, incident angle, distance, pressure, abrasive concentration, and nozzle diameter are investigated. Al2O3 is the abrasive used. The surface quality is evaluated visually and also measured with an optical profiler. The mechanical strength of the polished holes are evaluated with an MTS testing machine. Planar surfaces, and the surfaces of drilled and water cut holes are greatly improved by polishing. For a planar surface the lowest root mean square surface slope, Sdq, value achieved is 0·5 deg using 50% abrasive and 1000 mesh grains. The failure load of the glass with drilled holes increased 20% with FJP

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