Adaptive Cruise Control System

                To be an active member in the productive sector, you need to reach on time to your workplace. But with the increasing amount of automobiles, the traffic has also increased. So it is hard to cope up with slow-moving traffic when you are late. As a result, the number of accidents happening are also a way high than ever. To curb this, an AI called Adaptive Cruise Control System was developed.

Adaptive Cruise Control (ACC) is an automotive feature that allows a vehicle's cruise control system to adapt the vehicle's speed to the traffic environment. A radar system attached to the front of the vehicle is used to detect whether slower moving vehicles are in the ACC vehicle's path. The driver sets the maximum speed — just as with cruise control — then a radar sensor watches for traffic ahead, locks on to the car in a lane, and instructs the car to stay 2, 3, or 4 seconds behind the person car ahead of it (the driver sets the follow distance, within reason). ACC is now almost always paired with a pre-crash system that alerts you and often begins braking.

For an instance, If a slower moving vehicle is detected, the ACC system will slow the vehicle down and control the clearance, or time gap, between the ACC vehicle and the forward vehicle. If the system detects that the forward vehicle is no longer in the ACC vehicle's path, the ACC system will accelerate the vehicle back to its set cruise control speed. This operation allows the ACC vehicle to autonomously slow down and speed up with traffic without intervention from the driver.

The method by which the ACC vehicle's speed is controlled is via engine throttle control and limited brake operation.

TYPES

·       LASER-BASED SYSTEM do not detect and track vehicles in adverse weather conditions nor do they reliably track dirty (and therefore non-reflective) vehicles. Laser-based sensors must be exposed, the sensor (a fairly large black box) is typically found in the lower grille, offset to one side.

·       RADAR-BASED SENSOR can be hidden behind plastic fascias; however, the fascias may look different from a vehicle without the feature. For example, Mercedes-Benz packages the radar behind the upper grille in the center and behind a solid plastic panel that has painted slats to simulate the look of the rest of the grille.

·       SINGLE RADAR SYSTEM are the most common. Systems involving multiple sensors use either two similar hardware sensors like the 2010 Audi A8 or the 2010 Volkswagen Touareg, or one central long range radar coupled with two short radar sensors placed on the corners of the vehicle like the BMW 5 and 6 series.

A more recent development is the BINOCULAR COMPUTER VISION SYSTEM, such as that introduced to the US market in model year 2013 by Subaru. These systems have front-facing video cameras mounted on either side of the rear view mirror and use digital processing to extract depth information from the parallax between the two cameras' views.

Assisting systems

Radar-based ACC often feature a precrash system, which warns the driver and/or provides brake support if there is a high risk of a collision. Also in certain cars it is incorporated with a lane maintaining system which provides a power steering assist to reduce steering input burden on corners when the cruise control system is activated.

Multi-sensor systems

Systems with multiple sensors can practice sensor fusion to integrate the data from to improve safety and/or driving experience. GPS data can inform the system of geographic features such as a freeway off-ramp. A camera system could notice driver behavior such as brake lights and/or a turn signal. This could allow a following car to interpret a turn signal by an exit as not requiring the following car to slow down, as the leading car will exit. Multi-sensor systems could also take note of traffic signs/signals and not, e.g., violate a red light while following a vehicle that crossed before the signal changed.

Predictive systems

Predict systems modify speed based on predictions of other vehicles' behavior. Such systems can make earlier, more moderate adjustments to the predicted behavior, improving safety and passenger comfort. One example is to predict the likelihood of a vehicle in a neighboring lane moving in front of the controlled vehicle. One system predicts a lane change up to five seconds before it occurs.

ACC RADAR ANTENNA

ADVANTAGES & DISADVANTAGES OF ACCS

·       ADVANTAGES

1. The driver is relieved from the task of careful acceleration, deceleration and braking in congested traffics.

2. A highly responsive traffic system that adjusts itself to avoid accidents can be developed.

3.  Since the breaking and acceleration are done in a systematic way, the fuel efficiency of the vehicle is increased.

·       DISADVANTAGES

1. A cheap version is not yet realized.

2. A high market penetration is required if a society of intelligent vehicles is to be formed.

3. Encourages the driver to become careless. It can lead to severe accidents if the system is malfunctioning.

4. The ACC systems yet evolved enable vehicles to cooperate with the other vehicles and hence do not respond directly to the traffic signals.

Helpful Video Links

https://www.youtube.com/watch?v=IMYi3G7dkU4

https://www.youtube.com/watch?v=hBc_QPkhX-c

                       Image courtesy :- Google Inc.