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Extreme GTI Perfects Safety and Dynamics

Prototype for chassis development accelerated without driver handling courses

Golf GTI 53+1 provides valuable data for chassis development
Active safety – and thereby the avoidance of accidents – is a key concept in vehicle development. Today more accidents are being avoided than ever due to active safety systems, in particular, which have that have experienced continuous progress. A prime example of such systems is the Electronic Stabilization Program (ESP). Volkswagen is counting on its most innovative development processes and technologies to further improve on the status quo, enhance active safety and simultaneously – with intensified use of new innovative driver assistance systems – optimize dynamics. The latest example: A "self-driving" Golf. Its name: GTI 53+1. It is a driving machine for chassis development. It helps to ensure that safe cars that are developed are not boring; the goal instead is to achieve dynamically safe cars. The Golf GTI 53+1 supports its "makers", the specialists in driving dynamics at Volkswagen research, in attaining the best possible chassis from the hardware and software used. The 53 is reminiscent of the cinematic Volkswagen bug Herbie, which made movie history as the first "self-driving" Volkswagen with this starting number.

Chassis and Assistance Systems for more safety and fun

Back to the job of the driving robot, the Golf GTI 53+1: Providing the foundation for the best possible active safety and greatest driving fun is an optimal fundamental layout of the chassis and a concentrated integration of driver assistance systems. Safety systems such as ESP are intended to prevent hazardous situations. However, they cannot do this by simply "shutting off" the car. Rather, driver assistance systems must contribute to the basic talents of the vehicle to safely master the possibilities of vehicle dynamics. The driving experience should stay fun, while continuing to enhance safety. To achieve precisely this objective more ideally than ever, Volkswagen developed the Golf
GTI 53+1. It steers, brakes and accelerates. And if asked to, it does this at top performance and at the limits of what is feasible.

Race courses for the GTI 53+1 are constantly changing

Volkswagen engineers conduct test drives with the Golf GTI 53+1 on practically all kinds of marked circuit courses. Example: Ehra-Lessien, the Volkswagen test track at Wolfsburg. That is where courses are staked out that the Golf GTI 53+1 drives fully automatically and at maximum performance. The Volkswagen has been achieving – and this by the way is extremely noteworthy –course times that are just as fast as those of practiced professional drivers. The fact is: Measurement results demonstrate a very high level of reproducibility.

Golf GTI 53+1 enables objective and reproducible analyses

Reproducible driving maneuvers, such as those achievable by the Golf GTI 53+1, facilitate more focused vehicle development. In particular, analytically separate evaluations of vehicle dynamics (functionality of systems), driving behavior (effects of systems) and driving conditions (environmental effects) are of decisive importance here. However, none of this would be possible without an automated system that can assume the functionality of the vehicle driver with sufficient precision. The Golf GTI 53+1 does this, and it therefore rises to the challenge of studying vehicle and driver influences in a more differentiated manner. The defined objective here: To recognize and correct vehicle weaknesses in dynamic driving tests more accurately. Similarly the clever GTI can be used to study – with a view toward later model-specific variants – a broad spectrum of chassis tuning characteristics and to individually configure them. And indeed this can be done in a very early phase of vehicle development. An overview of the performance potential of the Golf GTI 53+1:

  • 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


Special note

This topic currently forms part of Volkswagen Group Research activities to study feasibility and does not constitute part of series equipment, nor are there currently any plans for series use.