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#It takes more time to accelerate and decelerate when driver

This factor helps the cruise control respond quickly to changes, such as hills. Remember that the derivative of speed is acceleration. Now let's add in the final factor, the derivative. After a little while, the integral control will start to increase the throttle, opening it more and more, because the longer the car maintains a speed slower than the desired speed, the larger the distance error gets. The proportional control increases the throttle a little, but you may still slow down. Let's say your car starts to go up a hill and slows down. This factor helps the car deal with hills, and also helps it settle into the correct speed and stay there. Translation: the difference between the distance your car actually traveled and the distance it would have traveled if it were going at the desired speed, calculated over a set period of time. The integral factor is based on the time integral of the vehicle speed error. We've already discussed the proportional factor.

The derivative of speed is acceleration.Ī PID control system uses these three factors - proportional, integral and derivative, calculating each individually and adding them to get the throttle position.

Don't worry, you don't need to know any calculus to make it through this explanation - just remember that: Most cruise control systems use a control scheme called proportional-integral-derivative control (a.k.a. Also, if you were on a steep enough hill, the car might not accelerate at all. The result is that the closer the car gets to the desired speed, the slower it accelerates. When the car is going 55 mph, the throttle position opening will be only half of what it was before. So, if the cruise control is set at 60 mph and the car is going 50 mph, the throttle position will be open quite far. In a proportional control system, the cruise control adjusts the throttle proportional to the error, the error being the difference between the desired speed and the actual speed. First, let's start with one of the most basic control systems you could have - a proportional control. The most important input is the speed signal the cruise control system does a lot with this signal.

The brake pedal and clutch pedal each have a switch that disengages the cruise control as soon as the pedal is pressed, so you can shut off the cruise control with a light tap on the brake or clutch.

On this car, tapping the coast button once will cause the car to slow down by 1 mph.

Holding down the coast button will cause the car to decelerate, just as if you took your foot completely off the gas.If you recently disengaged the cruise control by hitting the brake pedal, hitting the resume button will command the car to accelerate back to the most recent speed setting.Holding down the set/accel button will make the car accelerate and on this car, tapping it once will make the car go 1 mph faster. If you hit the set button at 45 mph, the car will maintain your speed at 45 mph.

The set/accel button tells the car to maintain the speed you are currently driving.

#It takes more time to accelerate and decelerate when driver

Some cruise controls don't have these buttons instead, they turn off when the driver hits the brakes, and turn on when the driver hits the set button. The off button turns the cruise control off even if it is engaged. Hitting the on button does not do anything except tell the car that you might be hitting another button soon. The on and off buttons don't actually do much.