Magnus Sethson

Modelling and validation of a fast switching valve intended for combustion engine valve trains

Abstract In recent years much research has been done in the area of variable-valve actuation in order to improve the efficiency of combustion engines. Currently, a number of different concepts for variable-valve actuation are under development or at a prototype stage. Hydraulic actuation has been an obvious candidate, but the lack of sufficiently fast switching valves with appropriate flowrates has been the major shortcoming. Design of such highly dynamic systems requires accurate models of the actual included components. In this paper a model of a fast 2/2 switching valve is presented, where both the magnetic path as well as the spool assembly are modelled. The model presented here is primarily aimed at system simulations; therefore it has to be kept simple with the number of parameters low. Some of the parameters are often hard to obtain, especially when it comes to magnetic material properties. In this study, an optimization strategy has been utilized in order to parameterize the model against measured data. However, even for major deviations from the operational point used for the model adaptation, the model predicts the valve response sufficiently accurately.

Hough Transform for Parking Space Estimation Using Long Range Ultrasonic Sensors

This paper describes a system for supporting the driver of a passenger car in different parking situations. Todays cars are getting larger in size and the drivers view in both forward and rearward ...

An XML-Based Model Representation for Model Management, Transformation and Exchange

Modeling and simulation in engineering design has traditionally been domain-specific and tool-centered. Due to limitations in computer speed and simulation software, only limited problems could be analyzed thus resulting in simulation within only one domain using one specific tool. When products become more complex and integrated, it is necessary to study the interactions between sub-systems from different domains. The domains could be e.g. mechanics, electronics or hydraulics. Such integrated analysis is difficult to undertake since the tools used in each domain have their own representation of the models, only focusing on the specific task for that tool. Less often is the tool providing a general base for representing models. In the paper, a model representation based on the eXtensible Markup Language, XML, is proposed as a bridge for transformation between different model representations. It is at the same time a model repository that many tools can make use of. The dynamic behavior can be specified both implicitly and explicitly enabling transformations to specific simulation tools or standalone simulators. The content of the XML-document is presented and it is discussed how transformations can be accomplished in a straightforward fashion using standard tools for XML. Furthermore, the importance of that the model can be developed and extended throughout the whole product development process is discussed. This requires an extensible, model-centric environment, where it is possible to access the model with more than one tool. The presented XML-document for simulation models is designed with such a model-centric environment in mind. The main purpose of this paper is to introduce the reader to the tools and standards that are useful in creating a flexible solution for product modeling. By using the proposed concept, models can be created and then be accessed by arbitrary tools and at any point in the design process.Copyright

Ultrasonic sensor modeling for automatic parallel parking systems in passenger cars

The performance of a parking system is dependent on many factors. One is the placement of the sensors. In this paper a system which uses ultrasonic ranging sensors is considered. The mounting of a ...

Interactive Internet based pendulum for learning mechatronics

This paper describes an Internet based remote experimental setup of a double lined pendulum mechanism for students experiments at the M. Sc. Level. Some of the first year experience using this web-based setup in classes is referred. In most of the courses given at the division of mechanical engineering systems at Linkoeping Institute of Technology we provide experimental setups to enhance the teaching Of M.Sc. students. Many of these experimental setups involve mechatronical systems. Disciplines like fluid power, electronics, and mechanics and also software technologies are used in each experiment. As our campus has recently been split into two different cities some new concepts for distance learning have been studied. The one described here tries to implement remotely controlled mechatronic setups for teaching basic programming of real-time operating systems and analysis of the dynamics of mechanical systems. The students control the regulators for the pendulum through a web interface and get measurement results and a movie back through their email. The present setup uses a double linked pendulum that is controlled by a DC-motor and monitored through both camera and angular position sensors. All software needed is hosted on a double-processor PC running the RedHat 7.1. distribution complemented with real-time scheduling using DIAPM-RTAI 1.7. The Internet site is presented to the students using PHP, Apache and MySQL. All of the used software originates from the open source domain. The experience from integrating these technologies and security issues is discussed together with the web-camera interface. One of the important experiences from this project so far is the need for a good visual feedback. This is both in terms of video speed but also in resolution. It has been noticed that when the students makes misstates and wants to search the failure they want clear, large images with high resolution to support their personal believes in the cause of the failure. Even if the student does not need a high resolution image to get the idea of the mechanics and the function of the pendulum, they need such high quality images to get confidence in the hardware. It is important to support this when the ability to direct hand-on contact with the hardware is taken away. Some of the experiences in combining open source software; real-time scheduling and measurement hardware into a cost efficient way is also discussed. The pendulum has been available publicly on the Internet but has now been removed due to security issues.