Topology-Based Vehicle Systems Modelling by Edward Kar-Yun Yam A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree of Master of Applied Science in Mechanical Engineering Waterloo, Ontario, Canada, 2012 © Edward Kar-Yun Yam 2012 I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners I understand that my thesis may be made electronically available to the public. Author’s Declaration ii Abstract The simulation tools that are used to model vehicle systems have not been advancing as quickly as the growth of research and technology surrounding the advancements of vehicle technology itself. A topological vehicle systems modelling package would use Modelica to take advantage of the flexibility and modularity of the language, the inherent multi-domain workspace and analytical accuracy of model equations. This package is defined through the use of SuperBlocks, a generalized model that allows the user to select and parameterize the appropriate sub-system directly within the workspace. This palette of SuperBlocks would be implemented within MapleSim6 to create MapleCar. This provides a customized balance between speed and accuracy after taking advantage of advanced graph-theoretic solutions methods used in MapleSim. MapleCar provides several advantages to a user over conventional tools. The SuperBlocks would ease the required steps to model a full vehicle system by providing clear, simple connections to quickly get a simulation assembled. Next, each SuperBlock is represented by a model that contains a replaceable model, a Modelica function which allows its internal model to be changed through a user-friendly parameter selection. The combination of sub- systems accessible directly through a parameter allows a variety of vehicle systems to be easily assembled, as well as provide a container for future models to be shared and published. A short demonstration of connecting these vehicle SuperBlocks from the MapleCar package is provided using MapleSim6. The generalized vehicle component palette provides a straight-forward, customizable drag-and-drop interface to assist in generating vehicle models for simulation. Conclusions and recommendations are provided at the end. iii Acknowledgements I would like to give my thanks to my supervisor Dr. Amir Khajepour for taking me on as his graduate student. Dr. Khajepour along with visiting professor Avesta Goodarzi and post-doctoral fellow Alireza Kasaiezadeh have used their combined expertise in the field of Automotive Research to create the initial proposition of this work which targets some of the issues with current software. This grand vision, along with continuous meetings and updates throughout the terms, helped guide the development of this new Modelica-based MapleSim package. I would also like to extend my thanks to Professor John McPhee and his research group, alongside Orang Vahid and Chad Schmitke from MapleSoft for providing technical assistance and vehicle model reference material within MapleSim. Within Dr. Khajepour’s group, I was first to work with both MapleSim and Modelica to specifically analyze vehicle dynamics, and they provided many helpful insights along the way. Finally, I would like to thank my friends and family for continuously providing spiritual and emotional support throughout the years. My friends have been with me since freshmen year in undergrad here at the University of Waterloo. I respect each and every one of them, and all have begun a successful transition into real life. Laphroaig and Bowmore were always great accompaniment during early mornings and stressful nights on campus. My family has strived for academic excellence and I hope to make them proud. iv Table of Contents Author’s Declaration .................................................................................................................... ii Abstract ......................................................................................................................................... iii Acknowledgements ...................................................................................................................... iv Table of Contents .......................................................................................................................... v List of Figures ............................................................................................................................... ix List of Tables ............................................................................................................................... xii 1. Introduction ............................................................................................................................... 1 2. Literature Review ..................................................................................................................... 4 2.1 Matlab and Simulink ............................................................................................................. 4 2.1.1 How it Works.................................................................................................................. 5 2.1.2 How it's Used .................................................................................................................. 5 2.2 MSC.Adams .......................................................................................................................... 7 2.2.1 How it Works.................................................................................................................. 7 2.2.2 How it's Used .................................................................................................................. 8 2.3 CarSim ................................................................................................................................... 9 2.3.1 How it Works................................................................................................................ 10 2.3.2 How it's Used ................................................................................................................ 11 v 2.4 Dymola ................................................................................................................................ 12 2.4.1 How it Works................................................................................................................ 13 2.4.2 How it’s Used ............................................................................................................... 15 2.5 Maple and MapleSim .......................................................................................................... 16 2.5.1 How it Works................................................................................................................ 17 2.5.2 How it's Used ................................................................................................................ 19 2.6 Software Discussion ............................................................................................................ 19 2.6.1 Flexible Design Approach ............................................................................................ 20 2.6.2 Encapsulated Multi-Domain Simulations ..................................................................... 22 2.6.3 Flexibility of the Mathematical Model ......................................................................... 24 2.6.4 Analytical Accuracy ..................................................................................................... 25 2.6.5 A Unified Platform for Research .................................................................................. 26 3. Vehicle Modelling and Analysis Using a Topological Approach ........................................ 29 3.1 Top-Level Definition........................................................................................................... 29 3.2 The SuperBlock ................................................................................................................... 34 3.3 Interaction of the SuperBlocks ............................................................................................ 38 3.4 SuperBlock Palettes............................................................................................................. 39 vi 3.4.1 Chassis SuperBlock ...................................................................................................... 40 3.4.2 Suspension SuperBlock ................................................................................................ 42 3.4.3 Sensors, Controllers ...................................................................................................... 44 3.4.4 SuperBlock Summary ................................................................................................... 45 4. Implementation of the Topological Vehicle Modelling and Analysis Tool ........................ 47 4.1 Package File Structure ......................................................................................................... 47 4.2 Layout of a SuperBlock Palette ........................................................................................... 49 4.3 Example of a MapleCar SuperBlock ................................................................................... 49 4.4 Extending Pre-Existing Packages.......................................................................................