The steering angle sensor is an important part of the electronic control system of the car that measures the steering wheel position angle and rate of turn.
The modern cars are equipped with systems that require steering-angle information. This sensor is located in a sensor cluster in the steering column.
A unique feature of this steering-angle sensor is the output of the correct angle within the measurement range directly after ignition-on.
The steering angle and steering-angle velocity are made available via the controller area network interface.
Sensor-internal plausibility tests and special self-diagnostic functions allow the use of this sensor in safety systems.
The steering angle sensor is fixed onto the steering shaft, where the hub gear wheel of the sensor transmits the rotary movement of the shaft to two measuring gear wheels.
In each measuring gear wheel, a magnet is mounted, whose field changes its direction in accordance with the rotational movement.
The analog values of the GMR elements are converted into digital information directly on the circuit, which is then sent to the microprocessor via a serial interface.
The measuring gears have different numbers of teeth and therefore change their turning position at different speeds.
This measuring principle enables the measurement of the complete angle range of several steering-wheel turns without the use of a rotation counter.
The angle of the steering on its own can be used to determine where the front wheels are pointed.
When combined with other pieces of information from the accelerometer and wheel speed sensors, it is possible to measure the dynamics of the car.
In cars, the steering angle sensor has two or three sensors packaged together. The reason for multiple sensors is redundancy, accuracy and diagnostics.
The steering angle sensors are electronic units and it is nearly impossible to know them from the outside.
So, in order to have your car effective at ABS and stability control diagnostics, knowing how sensors measure angles and information is critical.
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