PEUGEOT DEVELOPS NEW URBAN DRIVE CONTROL
As part of the European Telematics Applications (ETA) project Peugeot has helped develop a revolutionary Urban Drive Control (UDC) system designed to dramatically improve road safety, reduce emissions and smooth urban traffic flow.
The result of three years research, the UDC system is built around two key dynamic elements: longitudinal vehicle control and speed control recognising road condition and traffic density.
On-road development, completed in late 1998, was done using a Peugeot 406 sedan fitted with the 4HP20 automatic gearbox. Italy's beautiful but congested Turin was chosen as the trial city.
The UDC system is based on a network of microwave masts or beacons constantly communicating with the vehicle and instigating automatic and semi-automatic functions.
The vehicle is equipped with a radar located behind the front number plate, two short range sensors located near the headlights and a computer which controls throttle position and brake pressure.
Inside an LCD screen in the centre console, includes readouts for the speed setting dictated by the driver, obstacles in the roadway (indicated by a pictogram) and up-coming road signs (speed limit, traffic lights, stop sign, give way, etc).
This sophisticated array of on-board and external hardware supports a range of functions aimed at informing and helping the driver cope safely and efficiently with a variety of challenging traffic situations.
Some functions adjust the car's speed and braking automatically but UDC allows the driver to take control at any time. The impressive power and flexibility of the UDC system is apparent in its range of key modes including:
ADAPTIVE CRUISE CONTROL (ACC)
The Adaptive Cruise Control function is used for highway and motorway driving at speeds between 40 km/h and 160 km/h.
The driver selects cruise speed by pressing the Cruise Control lever on the left-hand side of the steering wheel and activates ACC by pressing a button on the left of the console display screen. The vehicle will then adapt automatically to traffic conditions without requiring driver action on the accelerator or brake.
When the car radar detects a slower vehicle in front within the same speed range, the computer actuates the braking system to slow the car gradually until reaching a safe distance between the two vehicles.
The safe distance varies according to weather conditions and vehicle speed. It is computed on a reaction time of 1.2 seconds. The ACC vehicle then adopts the speed of the vehicle in front. If the vehicle in front leaves the field of view of the radar, the ACC vehicle resumes the initial cruise speed.
The function is automatically deactivated if the vehicle goes into too tight a turn, reaches a speed outside the 40-160 km/h speed range or in case of emergency braking (pressure above 50 bars).
STOP & GO
The Stop & Go function is used for city driving at speeds below 60 km/h. It operates on a similar principle to the ACC function.
The car adjusts to the speed of the vehicle in front, from which it keeps a safe distance. It is capable of stopping behind the vehicle and restarting with it.
As for the ACC function, the driver is always in ultimate control of the vehicle. He or she can temporarily inhibit the Stop & Go function by pressing the brake or accelerator, or cancel it by pulling out the Cruise Control lever.
The function is automatically deactivated if the vehicle goes into too tight a turn, exceeds 60 km/h or in case of emergency braking.
The ACC and Stop & Go modes can be selected simultaneously, the transition from one to another made automatically according to the vehicle speed.
TRAFFIC LIGHT CONTROL (TLC)
Traffic Light Control provides the driver with speed settings adapted to the traffic density and traffic light cycle times. The urban traffic control centre measures traffic density on main thoroughfares and calculates an optimum driving speed.
This recommended speed is communicated to the vehicle by strategically located 5.8 GHz microwave beacons.
When the TLC function operates in concert with the ACC mode the vehicle speed is adjusted to match the settings and conditions. The recommended speed setting is based on road type and traffic density. Information is displayed on the console screen and vehicle speed is set automatically.
When the Stop & Go mode is active, the vehicle calculates information concerning the colour and distance of the next traffic light. It adjusts its speed, within the authorised range, to try to reach the light when it is green.
If traffic conditions are tight and the computer estimates that the car won't have enough time to reach the light while it is still green, the system starts gradual deceleration 120 metres from the light to bring the vehicle to a complete stop.
When the traffic light turns green, and if the vehicle is first at the light, the Go panel is displayed until the driver acknowledges it by pressing the accelerator. Starting is not automatic for safety reasons.
THE NEXT PHASE
The potential benefits of the UDC system, in terms of improved safety, fuel economy, reduced emissions and smoother traffic flow are enormous and ETA project partners, PSA Peugeot Citroën, Fiat, Jaguar, Renault (and related equipment manufacturers), are discussing an extension of the system through an additional three year development program.