Car Speed Control System

Automobile car speed control system

The driver is the controller of the system , when he push or loose the throttle(the actuator), he controls the speed, disturbance such as hills and friction will affect the speed , the feedback sensor which is the speedometer will measure the changes in speed which the human eyes can read , On this basis the driver will increase or decrease the speed by pushing or leaving the throttle .

Or:

We can use digital speed stabilizer system , where we can make a set point for a desired speed , the digital sensor will measure the speed and fed it back to a comparison element to compare it with the input set point , so it can automatically keep the speed constant .

The output of the comparison element will be connected to the controller so it can increase or decrease the speed of the engine to eliminate the difference between the actual and set point speed.

operation :

Cruise control is a system that automatically controls the speed of an automobile. The driver sets the speed and the system takes over the throttle of the car to maintain the speed. The system thereby improves driver comfort in steady traffic conditions. In congested traffic conditions, where speeds vary widely, these systems are no longer effective. Most cruise control systems do not allow the use of cruise control below a certain speed.

In modern designs, the cruise control may need to be turned on before use -- in some designs it is always "on" but not always enabled (not very common), others have a separate "on/off" switch, while still others just have an "on" switch that must be pressed after the vehicle has been started. Most designs have buttons for "set", "resume", "accelerate", and "coast" functions. Some also have a "cancel" button. Alternatively, depressing the brake or clutch pedal will disable the system so the driver can change the speed without resistance from the system. The system is operated with controls easily within the driver's reach, usually with two or more buttons on the steering wheel spokes or on the edge of the hub like those on Honda vehicles, on the turn signal stalk like in many older General Motors vehicles or on a dedicated stalk like those found in some Toyota, Mercedes-Benz and Lexus vehicles. Earlier designs used a dial to set speed choice.

The driver must bring the vehicle up to speed manually and use a button to set the cruise control to the current speed. The cruise control takes its speed signal from a rotating driveshaft, speedometer cable, wheel speed sensor from the engine's RPM, or from internal speed pulses produced electronically by the vehicle. Most systems do not allow the use of the cruise control below a certain speed (normally around