Lap Time Simulation for Racing Car Design

Abstract

The candidate confirms that the work submitted is his own work and that appropriate credit has been given where reference has been made to the work of authors. As LTS are computationally intensive, previous packages have simulated a full lap using a quasi-static method which splits the path of the vehicle into segments. An analysis is then made of the vehicle at each segment point using the external forces acting on the vehicle. Due to the constant acceleration (i. e. steady state) assumption across each segment, this method does not take into account the effect of roll, pitch and yaw inertia as well as damping and tyre lag effects. Another aspect that is not accounted for is the variation in the fastest effective vehicle path along the circuit (i. e. racing line) due to change in driver control inputs or vehicle parameters.The overall aim of this thesis is to develop a transient LTS methodology, which adopts a strategy to vary the racing line taken in order to address the problems found with the existing quasi-static LTS packages. In parallel an investigation of the accuracy of vehicle models in relationship to racing car performance has been developed.The thesis begins with a study of racing car modelling techniques and a review of current LTS packages. A description is then given of the collection of vehicle iii handling data from an actual racing car (along with attaining a vehicle parameter set) and the measured results displayed and discussed. Finally, the creation of two simulation packages has been detailed and case studies are presented to provide further insight into the look and feel of the packages. The first package is a quasi-static approach based LTS package, where a case study is made into the sensitivity of overall lap time to a range of vehicle parameters. The second is a transient approach based simulation package which optimises the driver controls, varying the racing line taken by the vehicle and ensuring the manoeuvre is completed in the quickest time for that vehicle parameter set. This final Manoeuvre Time Minimisation package fulfils the overall aim of the thesis and a case study is made into the effect of front damping value on manoeuvre completion time.

Modelling and Validation of the Vehicle Longitudinal Model

“…The longitudinal slip of the tyres is given as = − max ( , ) . To represent the characters of the tyres, the Pacejka Magic Formula tyre model proposed by [17]is used in this study. The mathematical equations as well as the parameters of the modelling can be seen in Aparow et al [7].…”

“…at time t = 2 seconds to t = 10 seconds, can be ignored. According to Siegler and Crolla [17], engine torque is used to accelerate the vehicle only and the effect of the torque on the braking is very small and can be neglected. As the vehicle longitudinal model is developed based on front-wheel drive, the effect of the engine during initial start-up occurs in the front wheels only.…”

“…Since the vehicle is front-wheel drive, there is no doubt that this condition could have occurred because the vehicle movement is triggered by the front wheelsin fact there is no input drive torque in the rear wheels. In other words, during heavy acceleration, weight is shifted from the front to the rear and causes increased traction in the rear wheels at the expense of the front driving wheels; consequently, longitudinal speed is raised in the front tyres as a result of wheel spinning [17].…”

Extended Steady State Lap Time Simulation for Analyzing Transient Vehicle Behavior

“…Instead of pre-calculating a g-g diagram, the maximum car potential can be calculated online in every time step as Siegler [5] used it to analyze simple corner maneuvers. He also developed an optimization process for the control input to calculate the minimal maneuver time for a transient vehicle.…”

TRT EVO: Advances in real-time thermodynamic tire modeling for vehicle dynamics simulations

“…The teams generally run a large amount of laps in the simulators, programmed with a variety of variables such as fuel loads and grip levels, to ensure as many scenarios as possible to be covered and to analyze as many race outcomes as possible. 2,3 Engineering advances in sensor technologies during the last years allowed to introduce sensing elements even inside the wheel. The bigger volume of data collected during both tests and races to be processed met the availability of the reliable and predictive physical models, able to tune the vehicle and its components for optimum performance.…”