Author: Anthony Pluck, Oxford Brookes Racing

1 - Why lap time simulation?

Lap time simulation has proved to be a valuable tool for OBR (Oxford Brookes Racing) as it saves the team a lot of time and money in both the design and the testing stage of our car build and testing process. Figure 1 shows how lap time simulation is incorporated in the design process in the OBR team.

During the design process OBUSim can be used to monitor the progress of weight and any other performance targets. Once the car has been built and testing has commenced, the lap time simulation team can investigate and validate any proposed set up changes, see figure 2.

2 - The OBUSim package:

In industry there are many lap time simulation packages available for purchase, but these are all essentially ‘black boxes’. Coding a simulation package in MATLAB allows engineers at Oxford Brookes University to see how the package works and also allows improvements/developments to the package to be made with relative ease.

The origins of the current OBUSim can be traced back to work by engineering students at Oxford Brookes creating very basic static state simulation packages in MATLAB in 2005, these have been developed to the quasi-static package that we are using today.

In addition to running individual simulations of a car set up, a sensitivity study can be carried out in order to determine how sensitive lap times are to changing any particular parameter, this allows areas that are very sensitive to be identified and more time spent developing these parameters. Figure 3 shows an example of a typical sensitivity study.

Included recently in OBUSim is a 2D track map generator and editor, the idea behind this comes from the fact that the circuits that were running in the simulation did not replicate the circuits actually running in real life to a high enough accuracy. Using the logged data from competitions and testing, track maps can be generated, they can then be edited and modified to a standard that will increase the accuracy of simulations.

Another useful tool that has been incorporated within the OBUSim software is a points scoring analyser and calculator system, this allows the team to study where the team lies within the competition. It also acts as a calculator to identify how many points are required to get to a certain position in the competition and also study other teams in the same manor.

3 - The future of OBUSim:

Further improvements to the OBUSim software are to include environmental conditions such as wind, rain, temperature and pressure variations. This will allow set up changes to be simulated and investigated in different weather conditions. Currently the simulation runs on 2D track maps, incorporating 3 dimensional track maps will further bring OBUSim closer to replicating reality.