23-03-2012, 02:04 PM
hybrid adaptive cruise control
New seminar Hybrid Adaptive Cruise Control System.docx (Size: 77 KB / Downloads: 88)
INTRODUCTION
Mentally, driving is a highly demanding activity - a driver must maintain a high level of concentration for long periods and be ready to react within a split second to changing situations. In particular, drivers must constantly assess the distance and relative speed of vehicles in front and adjust their own speed accordingly.
Those tasks can now be performed by Hybrid Adaptive Cruise Control (HACC) system, which is an extension of the conventional cruise control system.
Like a conventional cruise control system, HACC keeps the vehicle at a set constant speed. The significant difference, however, is that if a car with HACC is confronted with a slower moving vehicle ahead, it is automatically slowed down and then follows the slower vehicle at a set distance. Once the road ahead is clear again, the HACC accelerates the car back to the previous set cruising speed. In that way, HACC integrates a vehicle harmoniously into the traffic flow.
WHY HYBRID ADAPTIVE CRUISE CONTROL?
Comfortable distance to the car ahead increases driving safety and ensures a more relaxed driving experience. Hybrid Adaptive Cruise Control ensures that there is enough distance to the car ahead, even if it unexpectedly lowers the speed.
With Hybrid Adaptive Cruise Control we have enhanced the conventional systems for speed control to a driver assistant with an added value. The system makes it possible to adapt the distance to the car ahead without the driver’s intervention, effectively relieving the driver. Highway and rural road drives are more relaxed and traffic flows better altogether, since acceleration and braking maneuvers are automatically adjusted.
HYBRID ADAPTIVE CRUISE CONTROL
Two companies are developing a more advanced cruise control that can automatically adjust a car's speed to maintain a safe following distance. This new technology, called adaptive cruise control, uses forward-looking radar, installed behind the grill of a vehicle, to detect the speed and distance of the vehicle ahead of it.
Hybrid Adaptive cruise control is similar to conventional cruise control in that it maintains the vehicle's pre-set speed. However, unlike conventional cruise control, this new system can automatically adjust speed in order to maintain a proper distance between vehicles in the same lane. This is achieved through a radar headway sensor, digital signal processor and longitudinal controller. If the lead vehicle slows down, or if another object is detected, the system sends a signal to the engine or braking system to decelerate. Then, when the road is clear, the system will re-accelerate the vehicle back to the set speed.
HYBRID ADAPTIVE CRUISE CONTROL FEATURES
Maintains a safe, comfortable distance between vehicles without driver interventions
Maintains a consistent performance in poor visibility conditions.
Maintains a continuous performance during road turns and elevation changes
Alerts drivers by way of automatic braking.
ADVANTAGES
Some of those advantages include:
Its usefulness for long drives across sparsely populated roads. This usually results in better fuel efficiency.
Some drivers use it to avoid unconsciously violating speed limits. A driver who otherwise tends to unconsciously increase speed over the course of a highway journey may avoid a speeding ticket. Such drivers should note, however, that a cruise control may go over its setting on a downhill which is steep enough to accelerate with an idling engine.
Reduction in accident rate for vehicles fitted with collision avoidance type systems
Reduction in driver fatigue
Interconnection to more advanced future systems.
LIMITATIONS
One of the biggest challenges in designing ACC systems today are the costs associated with the robust system. Though current costs are substantial, they are slowly decreasing.
Auto manufacturers stress that advanced cruise control does not drive the car for you, and it's not meant to be used in heavy traffic. But, for long trips, it's a convenience that allows you to focus more on your driving.