Adaptive Cruise Control free essay sample

Cruise control system is developed for highway driving. This system is useful for driving in roads which are big, straight, and the destination is far apart. When traffic congestion is increasing, the conventional cruise control becomes less useful. The adaptive cruise control (ACC) system is developed to cope up with this situation. The conventional cruise control provides a vehicle with one mode of control, velocity control. On the other hand, ACC provides two modes of control, velocity and distance control. 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. We will write a custom essay sample on Adaptive Cruise Control or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page 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 doesnt 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 ACC-equipped car. Because the sweep sensors beam is so narrow, it doesnt see the other car until its smack in the middle of the lane. Thats 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 isnt 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 dont confuse it. Figure shows the sensor’s range, beam area and the minimum time gap. Information from the sensors goes to the microcontroller, the systems computing and communication center. The microcontroller reads the settings the driver has selected and communicates it to the fuzzy logic controller which 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. Figure shows the working of an ACC equipped vehicle. Here the preset speed is 140kmph. When there is no vehicle in the same lane ahead of it, the car cruises at the preset speed. When a vehicle is detected the fuzzy logic control lowers the speed in order to maintain a safe preset time gap between the two vehicles. If the preceding vehicle changes the lane, there is no obstacle ahead and so the car accelerates to and continues in the preset speed. The components of an ACC system equipped in a vehicle are shown below. Comfortable distance to the car ahead increases driving safety and ensures a more relaxed driving experience. Adaptive Cruise Control ensures that there is enough distance to the car ahead, even if it unexpectedly lowers the speed. With 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. Some of the advantages of ACC include : * It’s useful 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.