Guru
Introduction
Adaptive Cruise Control (ACC) is one technological advancement that has profoundly changed how we view highway travel as it continues to redefine the driving experience. The days of conventional cruise control systems are long gone, as advanced computerized guidance (ACC) dynamically modifies vehicle speed in response to traffic patterns. We'll go over the nuances of adaptive cruise control, its advantages, and how it's a major step toward safer and more intelligent driving in this blog.
Adaptive Cruise Control (ACC) is an automotive feature that allows a vehicle’s cruise control system to adapt the vehicle speed to the environment.A radar system attached to the front of the vehicle is used to detect whether slower moving vehicles are in the ACC vehicle path. 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 path, the ACC system will accelerate the back to its set cruise control speed.This operation allows the ACC vehicle to autonomously slow down and speed up is controlled is via engine throttle control and limited brake operation.
The Basics of Adaptive Cruise Control
Adaptive cruise control enables drivers to maintain a predetermined maximum speed typically suited for driving on long highway sections where there is no traffic. Adjustments to traditional systems are manual when the traffic conditions vary. The solution to this shortcomings is Adaptive Cruise Control, a smart technology.
1. Radar and Sensor Technology:
The act is designed to ensure a sustainable match between the available labor and the market demand for the same.In the core of the ACC, there is a range of sensors that mostly use radar or lidar tech, focused towards the front of the car. It continuously monitors the road forward that identifies the vehicular speed and distance of cars traveling on the same lane.
2. Dynamic Speed Adjustment:
While many people would probably agree that the traffic signals can be difficult to trust since most will drive through flashing red lights, a moral argument for ACC would be that it goes to the point in allowing the ACC to adjust the vehicle’s speed for a better chance of keeping an appropriate following distance and allowing the flow of traffic. If the path is free, the system keeps the pre-programmed speed. The problem is, if it drives slower car ahead, it will decelerate by ACC to stay safe distance.
3. User-Defined Settings:
Most ACC systems enable drivers to personalize their preferred following distance. Forca function is an adjustable user setting, which is safe for maintaining an appropriate gap of the distance between the vehicle and the front car depending on the speed in the freeway.
4. Stop-and-Go Capability:
In other advanced ACC systems, the technology goes beyond driving on the highway. This has been implemented by some of the models which include stop-and-go feature which allows the vehicle to come to a full stop when in traffic and to resume movement when allowed, hence the ease in the congested cities.
Benefits of Adaptive Cruise Control:
1. Enhanced Safety:
ACC contributes to improved safety because it manages the speed of the vehicle depending on the traffic surrounding the vehicle. The system’s ability to change with the environment but away from collisions and following accidents.
2. Reduced Driver Fatigue:
This is because ACC in its attempt to automate speed adjustment according to traffic conditions it reduces the cognitive workload among drivers. This can increase the sense of comfort and absence of tiredness of driving during long trips.
3. Optimized Fuel Efficiency:
ACC can help control vehicle speed dynamically, thereby increasing fuel efficiency. This combination of smooth speed provides better economic driving.
4. Convenience in Traffic:
In heavy traffic, stop-and-go function in certain ACC systems reduces complexity. In situations of traffic congestion, the vehicle automatically handles acceleration and deceleration, thus, drivers have a more comfortable ride.
Future Developments:
The features offered by Adaptive Cruise Control will likely continue to grow as automotive technology develops. Developments to semi-autonomous driving experiences could be possible through integration with other advanced driver assistance systems, like automated steering and lane-keeping assistance.
HOW DOES IT WORK?
The radar headway sensor sends information to a digital signal processor,which in turn translates the speed and distance information for a longitudinal controller. The result? 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.
The adaptive cruise control (ACC) system depends on two infrared sensors to detect cars up ahead. Each sensor has an emitter, which sends out a beam of infrared light energy, and a receiver, which captures light reflected back from the vehicle ahead.
The first sensor, called the sweep long-range sensor, uses a narrow infrared beam to detect objects six to 50 yards away. At its widest point, the beam covers no more than the width of one highway lane, so this sensor detects only vehicles directly ahead and doesn't detect cars in other lanes. Even so, it has to deal with some tricky situations, like keeping track of the right target when the car goes around a curve. To deal with that problem, the system has a solid-state gyro that instantaneously transmits curve-radius information to the sweep sensor, which steers its beam accordingly.
Another challenge arises when a car suddenly cuts in front of an ACCequipped car. Because the sweep sensor's beam is so narrow, it doesn't "see" the other car until it's smack in the middle of the lane. That's where the other sensor, called the cut-in sensor, comes in. It has two wide beams that "look" into adjacent lanes, up to a distance of 30 yards ahead. And because it ignores anything that isn't moving at least 30 percent as fast as the car in which it is mounted, highway signs and parked cars on the side of the road don't confuse it.
Information from the sensors goes to the Vehicle Application Controller (VAC), the system's computing and communication centre. The VAC reads the settings the driver has selected and figures out such things as how fast the car should go to maintain the proper distance from cars ahead and when the car should release the throttle or downshift to slow down. Then it communicates that information to devices that control the engine and the transmission.
There are several inputs:
- System on/off: If on, denotes that the cruise-control system should maintain the car speed.
- Engine on/off: If on, denotes that the car engine is turned on; the cruise control system is only active if the engine is on.
- Pulses from wheel: A pulse is sent for every revolution of the wheel.
- Accelerator: Indication of how far the accelerator has been pressed.
- Brake: On when the brake is pressed; the cruise-control system temporarily reverts to manual control if the brake is pressed.
- Increase/Decrease Speed: Increase or decrease the maintained speed; only applicable if the cruise-control system is on.
- Resume: Resume the last maintained speed; only applicable if the cruise control system is on.
- Clock: Timing pulse every millisecond.
There is one output from the system:
- Throttle: Digital value for the engineer throttle setting.
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.
PHYSICAL LAYOUT
The ACC system consists of a series of interconnecting components and systems. The method of communication between the different modules is via a serial communication network known as the Controller Area Network (CAN).
ACC Module
The primary function of the ACC module is to process the radar information and determine if a forward vehicle is present. When the ACC system is in 'time gap control', it sends information to the Engine Control and Brake Control modules to control the clearance between the ACC Vehicle and the Target Vehicle.
Engine Control Module
The primary function of the Engine Control Module is to receive information from the ACC module and Instrument Cluster and control the vehicle's speed based on this information. The Engine Control Module controls vehicle speed by controlling the engine's throttle.
Brake Control Module
The primary function of the Brake Control Module is to determine vehicle speed via each wheel and to decelerate the vehicle by applying the brakes when requested by the ACC Module. The braking system is hydraulic with electronic enhancement, such as an ABS brake system, and is not full authority brake by wire.
Instrument Cluster
The primary function of the Instrument Cluster is to process the Cruise Switches and send their information to the ACC and Engine Control Modules. The Instrument Cluster also displays text messages and tell-tales for the driver so that the driver has information regarding the state of the ACC system.
CAN
The Controller Area Network (CAN) is an automotive standard network that utilizes a 2 wire bus to transmit and receive data. Each node on the network has the capability to transmit 0 to 8 bytes of data in a message frame. A message frame consists of a message header, followed by 0 to 8 data bytes, and then a checksum. The message header is a unique identifier that determines the message priority. Any node on the network can transmit data if the bus is free. If multiple nodes attempt to transmit at the same time,an arbitration scheme is used to determine which node will control the bus.The message with the highest priority, as defined in its header, will win the arbitration and its message will be transmitted. The losing message will retry to send its message as soon as it detects a bus free state.
Cruise Switches
The Cruise Switches are mounted on the steering wheel and have several buttons which allow the driver to command operation of the ACC system.The switches include:
- 'On': place system in the 'ACC standby' state
- 'Off'': cancel ACC operation and place system in the 'ACC off' state
- 'Set +': activate ACC and establish set speed or accelerate
- 'Coast': decelerate
- 'Resume': resume to set speed
- 'Time Gap +': increase gap
- 'Time gap –': decrease gap
ADVANTAGES
- The driver is relieved from the task of careful acceleration, deceleration and braking in congested traffics.
- A highly responsive traffic system that adjusts itself to avoid accidents can be developed.
- Since the braking 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.
to be formed.
3.Encourages the driver to become careless. It can lead to severe accidents if
the system is malfunctioning.
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.
vehicles and hence do not respond directly to the traffic signals.
Conclusion
Adaptive Cruise Control represents a significant leap forward in the quest for safer, more efficient, and convenient driving. As this technology becomes increasingly prevalent in modern vehicles, it not only reduces the burden on drivers but also sets the stage for more sophisticated autonomous driving systems in the future. Navigating through traffic has never been more intelligent, thanks to the evolution of Adaptive Cruise Control.