Wireless Wheel Speed Detection
Precise Wireless Wheel Speed Detection:
RPM Measurement without Mechanical Influence
To measure various influences on the wheel speed, independent sensors are installed so their signals can be recorded independently of the vehicle.
These influences - referred to as wheel slip - can be caused by driving behavior. A distinction is made here between a locked wheel - the wheel is stationary, but the vehicle is still moving - or a spinning wheel - the wheel is already moving but the vehicle is still stationary. To prevent such phenomena, advanced driving assistance systems (ADAS) intervene in the vehicle control system. The aim is to detect the exact moment when wheel slip occurs. This can be precisely recorded in conjunction with a wheel speed sensor and a slip-free optical speed sensor.
Wheel slip can also be triggered by external influences, such as a snowy or icy road surface in winter or an extreme film of water or other liquid on the road, known as aquaplaning. In an aquaplaning phenomenon, the contact between the vehicle tires and the road surface breaks off due to the thick film of water, the vehicle slides on the water and starts to skid. Aquaplaning detection is very important in maintaining proper control of the vehicle.
To perform aquaplaning detection on wheels, special tests and instruments are needed. One of the most common methods for testing the aquaplaning behavior of tires is to use a water channel or basin. A vehicle is attached to a guide rail for the driver's safety and drives at increasing speed with one wheel in a water channel. As soon as the wheel starts to float, the speed of the wheel changes and the moment of aquaplaning is detected.
Aquaplaning measurements are important to improve the safety of vehicles and tires and to improve the behavior of vehicles on wet roads. Tire and vehicle manufacturers conduct such tests to ensure that their products meet the required standards and provide the best possible performance in different weather conditions.
There are new telemetry measurement solutions on the market to support wireless wheel speed system testing based on wireless sensors.
In contrast to conventional wheel pulse transducers, the wireless wheel speed system does not require a sensor cable, through which water can repeatedly penetrate the sensor and destroy it.
Furthermore, this improves the measurement accuracy by removing the need for a stator bracket, which requires large tolerances to be added in the measurement result due to the vibrations it generates.