2008:010 HIP
                                                                                                                                                                         BACHELOR’S  THESIS
                                                                                                                                                                                Vehicle dynamics
                                                                                                                                                               - optimization of Electronic Stability Program for sports cars
                                                                                                                                                                                            Johan Andersson
                                                                                                                                                                                                B.Sc PROGRAMME IN 
                                                                                                                                                                                          AUTOMOTIVE ENGINEERING
                                                                                                                                                                                               Luleå University of  Technology 
                                                                                                                                                                                 Department of Applied Physics and Mechanical Engineering 
                                                                                                                                                                                             Division of Computer Aided Design 
                                                                                                                                                                                                              
                                                                                                                 Universitetstryckeriet, Luleå                          2008:010 HIP • ISSN: 1404 - 5494 • ISRN: LTU - HIP - EX - - 08/010 - - SE
      Abstract 
       
      This thesis was performed during the spring of 2008 at the Bosch test facility in Arjeplog. The 
      thesis describes how to optimize the intervention of an ESP system for a sports car. The 
      problem with ESP today is that it is very often defensively programmed and affects the feel 
      when the car is driven. What to be researched in this thesis is if an optimization of the 
      program can be done that allows greater body slip without affecting the vehicle dynamics and 
      stability in a negative way. The thesis describes programming and simulation of ESP, the 
      code for ABS, TCS and ESP has been written and then tested in the simulation environment 
      where after the parameters and code have been changed in attempt to achieve a ESP that 
      allows greater body slip without compromising the stability.  
       
      The ESP has been created with several setups depending on wanted behaviour and 
      intervention. The results from the simulations shows that greater body slip is possible without 
      affecting stability, the feel when driving is more or less similar as without ESP and TCS. The 
      measurements prove that the lap times are faster with ESP in race mode compared to only 
      ABS and TCS. Worth to be mentioned is that a simulation is a reproduction of a real 
      measurement, results and feel can differ from the reality when testing a vehicle. 
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
      Keywords: ABS, ESP, TCS, vehicle dynamics, oversteer, understeer, lateral acceleration, 
      yaw rate, steady-state cornering  
                                              
      Sammanfattning 
       
      Detta examensarbete genomfördes under våren 2008 i Arjeplog på Bosch testanläggning. 
      Arbetet beskriver hur ingripande av ett antisladdsystem kan optimeras för en sportbil. 
      Problemet med ESP idag är att det ofta är väldigt defensivt inställt och påverkar känslan i 
      körningen av bilar. Det som undersöks är om en optimering av ESP kan göras som tillåter 
      större driftvinklar utan att påverka stabiliteten. Examensarbetet behandlar programmering och 
      simulering av antisladdsystem, kod för ABS, TCS och ESP har skrivits som sedan testats i 
      simulatormiljö varefter parametrar och koden ändrats för att försöka uppnå ett stabilt system 
      som tillåter ökade driftvinklar jämfört med standard.  
       
      ESP har skapats med olika inställningar beroende på önskat uppträdande och ingrepp. 
      Resultaten från simuleringen visar att ökade driftvinklar är möjliga utan att påverka 
      fordonsstabiliteten, känslan i körningen är nästan densamma som utan ESP och TCS. 
      Mätningarna visar att varvtiderna är lägre med ESP i raceläge jämfört med endast ABS och 
      TCS, ESP i normalläge samt endast ABS. Dock skall nämnas att en simulering är en 
      simulation av en verklig mätning, resultat och känsla kan vara annorlunda vid test på ett 
      fordon.  
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
       
      Nyckelord: ABS, ESP, TCS, fordonsdynamik, överstyrning, understyrning, sidoacceleration, 
      girvinkelhastighet (yaw rate), stationär kurvtagning 
                                              
      Preface 
       
      This is the thesis and final course of my three years to Bachelor of Automotive Engineering at 
      Luleå University of Technology. One of my biggest interests is cars, it has first of all been 
      very interesting to perform the education in Luleå, but the best part has of course been to 
      finalize all the theoretic knowledge in a thesis in a subject that I feel is very interesting.  
       
      During my time in Arjeplog where I except from my thesis also have worked some for 
      Arjeplog Test Management AB and Bosch with testing and presentations, I have learned a lot.  
      It has been great to do my thesis at such an interesting company and facility, this has given 
      me great knowledge in how the testing and developing of a new production car is performed.  
       
      I would like to thank Lars Holmgren, executive manager of ATM for giving me this 
      possibility to do my thesis at the Bosch facility.  
      Thanks to Jean-Marc Jacquin who was my examiner at ATM and helped me whenever I had 
      problems I could not solve by myself.  
      Thanks to Ove Isaksson that has been my examiner at Luleå University of Technology and 
      helped me with all kind of questions and thoughts throughout the thesis.  
      As well thanks to Frederic Potdevin at ATM that helped me with some questions about 
      simulation.  David Holmlund, Prashant Rana and Håkan Jonsson at ATM, thanks for the help 
      with the ABS code in the beginning.  
      Many thanks to Erik Hellström at Linköping University for all the help with the simulation 
      environment and the measurements. 
      Last of all, thanks to my girlfriend, my family and friends for being there for me all the time. 
       
       
                                      Umeå 08-06-03 
                                              
                                      Johan Andersson