The success of semi- or fully autonomous safety features is wholly dependent on the quality of data being supplied to the system. With ever-higher safety expectations from customers and regulatory bodies, OEMs and Tier 1s need to consider how to balance increasingly stringent requirements with the pressures of remaining competitive.

When people think of vehicle sensors, they often focus on vision systems that help cars navigate the external world. However, the sensors within the vehicle are just as crucial for both functionality and safety. Position sensors and resolvers are essential for precise motor control, while humidity and temperature sensors monitor the internal environment to enhance system reliability. Wheel speed sensors play a key role in providing feedback on driving conditions, helping prevent wheel lock during heavy braking, and helping provide vehicle stability.⁶ Internal sensors are the backbone of modern vehicle safety, helping the systems operate efficiently and securely.

The accuracy of these sensors is paramount, especially in fully autonomous vehicles and those equipped with advanced driver-assistance systems. Unreliable sensor data can pose serious risks, making it crucial to maintain the highest standards of reliability for consistent, safe performance.⁷

While there are many differing ideas as to what the future of autonomous driving technologies will look like, one thing is clear – there is a need to continue enhancing the safety and performance of vehicles in an increasingly complex driving environment. High resolution wheel speed sensors are one way of achieving precisely that, and this article will explore their role in improving safety systems.
 

These sensors operate in demanding conditions, exposed to extreme temperatures and limited protection from dirt and debris. Under heavy braking, the friction generates significant heat, causing rapid temperature fluctuations within seconds.

A typical modern wheel speed sensor measures rotational data using a magnetic encoder ring moving past the sensor. As the encoder wheel turns, sensitive elements detect changes in the magnetic field strength. The ASIC then converts the detected field strength into pulses that are sent to the vehicle control unit, typically the brake control unit.

Although wheel speed sensors have been used in ABS systems for many years, many existing designs struggle to meet the increasing demands of modern ADAS systems, including control at very slow speeds or detection of minor direction changes. This limitation can affect the performance and reliability of automated driving systems and limit the tasks that can be performed without human intervention to achieve better precision.
 

The HRWSS utilizes real-time magnetic signals combined with a processing algorithm to accurately monitor wheel positions. This approach mitigates edge jitter effects caused by natural fluctuations in the magnetic signal, helping provide precise output switching accuracy.

The HRWSS design also offers advanced stray field immunity, temperature compensation and ultra-precise detection of vehicle position and movement with continuous monitoring of wheel position on each pulse.

For OEMs and Tier 1 suppliers seeking sensors for advanced diagnostics, enhanced functional safety, or improved electronic stability control, the HRWSS provides significantly improved response times and helps meet higher SAE-defined levels for ADAS, particularly SAE levels 2+ and beyond. Its robust design withstands harsh environmental conditions, and its performance has been validated through rigorous testing and benchmarking.

The HRWSS exemplifies how advanced sensor technology can enhance driving experiences. It enables enhanced ADAS functionalities and stability control even in challenging and complex environments such as parking garages and traffic jams. The HRWSS is an excellent solution for facilitating motion path planning as more precise and accurate data can help reduce the risk of contact with another vehicle or object.