ANTI-LOCK BRAKING SYSTEMS
WITH WHEEL SPEED SENSORS
Kishore kumar
Dept. Informatik, Masters Automotive Software Engineering
Technische Universität Chemnitz
Chemnitz, Germany kishore-kumar@s2015.tu-chemnitz.de Abstract— In today’s life, Anti-Lock Braking System (ABS) are very common in new model cars. Anti-Lock Braking system have ability to control braking of the car under certain driving environments that in a loss of traction. This paper proposes how wheel speed sensor plays a vital role in decreasing the number of accidents of vehicles. Anti-lock braking system wheel speed sensors monitors the rotation of each wheel, making sure that each wheel is rotating properly. It emphasises about components of Wheel Speed Sensors, the two basic approaches of wheel Speed Sensors in modern
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TYPES OF WHEEL SPEED SENSOR
The Vehicle Wheel speed sensors are usually either Inductive Wheel speed sensor or Optical Wheel speed sensor.
A. Inductive wheel speed sensor: Fig. 5. Inductive Wheel speed sensor
Commonly used sensor in vehicles is inductive sensors, which consisting a rod magnet on top of a magnetic pin that is enclosed by a fixed coil. This inductive wheel speed sensor is mounted at a fixed distance from a ferromagnetic rotor with teeth. As the rotor rotates and a tooth comes near to the rod, the magnetic flux in the coil changes. This changes in the magnetic flux which results in a voltage pulse across the fixed coil. The vehicle’s Anti-lock braking system control module counts these voltage pulses and calculates the vehicle’s speed.
B. Optical Wheel speed sensor
Optical Wheel Sensors which also generates pulses at an frequency which is corresponding to the rotor rotation, but in here instead of detecting magnetic flux in coil, the optical sensors measures either light allowed to pass through slits or reflected light. When using an optical wheel speed sensor the rotor either has dark
Fig. 6. Optical Wheel Speed