Prototype for chassis development accelerated without driver handling courses
Golf GTI 53+1 provides valuable data for chassis development
Chassis and Assistance Systems for more safety and fun
Race courses for the GTI 53+1 are constantly changing
Golf GTI 53+1 enables objective and reproducible analyses
- Reproduced driving studies at the limits of performance
- Objective evaluation of driving dynamics at the limits of performance
- Analysis of courses for ideal line planning
- Driver-independent ideal line
- New knowledge of driving dynamics and its control
- New knowledge of total vehicle behavior
- Potential analysis of production system
The GTI 53+1 is based on the 147 kW (200 HP) production series GTI. It has the basic talent required for this task right from the factory. For example, it is only necessary to add an in-vehicle computer (a MicroAutoBox from dSpace) together with suitable CAN BUS wiring to control the electromechanical power steering (EPS) – without which the project would not have been feasible – and a slightly modified electronically controlled gas pedal (EGas) for driverless driving. Meanwhile, the computer – with its highly complex software developed in collaboration with the University of Hamburg – has in the truest sense the capability of computing where, and at what speeds, the GTI has clearance between the cones.
Moreover, as one might expect the 53+1 has numerous other technologies on board that its counterparts "in the outside world" must do without. An example is DGPS. Every car with a satellite navigation system has a GPS receiver for receiving signals of the Global Positioning System to zero in on the car’s current location. Its accuracy is within just a few meters. However, since the GTI 53+1 needs to know its momentary location with even greater precision, it has a DGPS unit on board. This "differential GPS" enables navigation within the centimeter range, providing highly precise feedback. Nevertheless, it only operates properly if the DGPS-equipped vehicle is in the vicinity of a fixed terrestrial transmitter that corrects for measurement error caused by clouds. Furthermore, the 53+1 has an auxiliary brake booster on board. This active brake booster supplies appropriate deceleration values. An example here is the laser scanner: A laser scanner installed at the front of the vehicle, from the German systems specialist "IBEO", is responsible for acquiring data on the circuit course. The sensor acquires data over an area in front of the GTI 53+1 spanning an angle of 130 degrees.
This is how the Golf GTI 53+1 "learns"
Learning the driving segments marked by cones essentially consists of three phases. In the first phase the GTI acquires and measures the cone positions using a laser scanner during a very slow drive. It determines its own position on the course by DGPS. Afterwards, in the second phase the GTI evaluates – at a standstill – the acquired data by computer and determines the available driving space. Within this corridor an ideal line is computed as a target for lateral dynamic control, and a computation is made of how much leeway the GTI has to the right and left on the course. The ideal line to be driven is designed to minimize steering effort and driving distance, and it is computed in a stepwise manner by a special optimization method. The systems of the Golf GTI 53+1 use this as a basis for establishing the lateral dynamic profile and hence the actual line to be driven. Derived from this information are target values are such as maximum vehicle speed and longitudinal acceleration. During automatic driving in the extreme performance range the systems, in unison, attempt to approach the computed target values as perfectly as possible. Other control systems coordinate to correct for excessive understeering and oversteering.
Volkswagen will utilize this substantially more focused and intensive development process to achieve further perceptible improvements in the driving dynamics of its automobiles. Moreover: Sporty performance and safety in new vehicles can be optimized harmoniously now that the system implemented in the Golf GTI 53+1 enables clear differentiation between vehicle effects and driver effects. The ability to conduct dynamic driving tests with production vehicles while excluding driver effects allows specific driving situations to be driven very accurately, which in turn makes it possible to derive suitable actions very efficiently. The impact for production vehicles: Extremely well-balanced Volkswagen models, in which driving safety and driving fun complement one another optimally.
04 July 2006