The aim of this project is to remove the influence of the driver from the test loop. This is beneficial when doing repeatable tests, as well as during long time durability tests. The concept of Computerized Test Driver will be demonstrated on a full scale vehicle.
To remove the influence of the human driver, the concept of “Computerized Test Driver” (CTD) is introduced. By replacing the human driver with a computer, tests can be done repeatedly and reliably. Another benefit with a CTD is that a human need to rest, a computer does not. This is very useful during time consuming durability tests, especially when performed on rough surfaces that expose both the vehicle, as well as any person in it, to a large amount of stress.
When testing cars in general, it is important to take the drivers behavior and experience into account. A trained test driver is good at sensing different dynamic behavior (under-/over- steering, instability,…), and every driver does affect the vehicle motion in some way while driving, especially during low friction conditions. During a sudden turn on a slippery road, a trained driver may prevent the car from skidding by counter steering, while a bad driver may just let go of the steering wheel.
In the project, estimation of different vehicle parameters is done by analyzing the cars ability to follow a predefined path, using known and predictable steering inputs in conjunction with a motion model of the car. This is especially applicable during winter test on low friction surfaces when pushing the car to its limits and forcing the cars stability system into use.
Project leader: Håkan Fredriksson