TE Connectivity's high resolution wheel speed sensor is a custom design sensor that provides precise and accurate wheel speed and directional (forward/reverse) data. This sensor is essential for enhancing the performance of vehicles with advanced driver-assistance systems (ADAS) and autonomous driving capabilities. Developed through a strategic partnership between TE and a provider of industry-leading solutions in magnetic sensing and power ICs, our high resolution wheel speed sensor integrates advanced digital processing algorithms, giant magnetoresistance (GMR) technology, and custom packaging, all backed by state-of-the-art manufacturing.

How does the high resolution wheel speed sensor work?

A wheel speed sensor measures wheel 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. High resolution in this context is defined as additional pulses transmitted along with the primary pulses found on standard wheel speed sensors. This sensor features two communication modes (PWM and AKC) along with two high resolution modes (4 pulses per pole pair or 8 pulses per pole pair).

How does the wheel speed resolution differ from traditional wheel speed sensors?

With the capability to deliver a four times higher resolution than traditional wheel speed sensors, our high resolution wheel speed sensor significantly improves upon previous generations by providing more accurate wheel speed, position, and direction information (i.e. 5mm precision over a 2-meter tire circumference). This enhanced precision is crucial for advanced autonomous functionalities such as motion path planning, auto valet and parallel parking, autonomous emergency braking, enhanced hill assist, and many more.

What functional safety standards are available for the high resolution wheel speed sensor?

This sensor supports ASIL B (D) per ISO26262 and enables OEMs and Tier 1 suppliers to meet higher Society of Automotive Engineers (SAE) defined levels for Advanced Driver Assistance Systems (ADAS), particularly at SAE Levels 2+ and beyond, where vehicle systems manage critical driving functions independently.

What common challenges do engineers encounter in wheel speed sensing designs for automotive applications?

Addressing common challenges OEM and Tier 1 engineers face, our high resolution wheel speed sensor maintains ultra-low jitter across the full air-gap range and exhibits robust vibration immunity. It supports multiple output protocols and operates across a broad temperature range, ensuring rapid and reliable direction detection on all pulses, and providing instant feedback on vehicular movement changes. A fully automated, VDA audited manufacturing process provides defect-free, high-volume production. An exceptionally robust design and rigorous testing protocols help provide consistent and reliable performance in harsh environmental conditions.

What packaging options are available?

There are two packaging options available for high resolution wheel speed sensors:

• A connector version is available for various connector orientations and is the most common packaging.
• An in-bearing version is available in various outer size options. This packaging option helps reduce the number of parts through the integration of the wheel hub cap and the wheel speed sensor.

What type of technology does the high resolution wheel speed sensor use?

The high resolution wheel speed sensor utilizes Giant Magnetoresistance (GMR) technology, which delivers high magnetic sensitivity even for large air gaps. This advanced technology provides a significantly higher signal-to-noise ratio compared to Hall or Anisotropic Magnetoresistance (AMR) technologies. Additionally, it enables more advanced signal processing capabilities, including the generation of high resolution pulses and the reduction of jitter.

What output protocols are available for the high resolution wheel speed sensor?

• AK Protocol: The AK protocol allows diagnostic data to be sent alongside the speed pulse, offering two options: 4 pulses per pole pair (PPP) with a maximum operational frequency of 3.3 kHz and message cut off, and 8 pulses per pole pair with a maximum operational frequency of 4 kHz and a high speed cut off at 200 Hz. This protocol is ideal for applications requiring detailed diagnostic data.
• Pulse Width Modulation (PWM): The PWM protocol provides the fastest data rate in high resolution mode offering two options: 4 pulses per pole pair (PPP) with a maximum operational frequency of 3.3 kHz and message cut off, and 8 pulses per pole pair with a maximum operational frequency of 4 kHz and a high speed cut off at 1kHz.This protocol is ideal for applications requiring higher high speed cut off rates.

What are the ideal applications for high resolution wheel speed sensors?

The High Resolution Wheel Speed Sensor helps significantly improve performance and safety, supporting modern ADAS and next-generation autonomous vehicle functionalities. As OEMs and Tier 1 suppliers explore new autonomous functionalities, the potential applications for the HRWSS continue to expand. Current application examples include:

• Motion Path Planning: enables precise control and navigation through complex environments
• Autonomous Valet Parking: supports fully autonomous parking solutions, allowing vehicles to park without driver intervention
• Autonomous Parallel Parking: enhances the vehicle's ability to perform precise and accurate parallel parking maneuvers
• Autonomous Emergency Braking: detects rapid changes in wheel speed, enabling the vehicle to stop quickly and safely in emergency situations
• Enhanced Hill Assist: provides improved wheel speed and direction data to further reduce incline rollback
• Enhanced Traffic Jam Assist: facilitates smooth and controlled vehicle movement in stop-and-go traffic conditions
• Enhanced Lane Keep: delivers improved wheel speed and direction information to help maintain lane position more accurately
• Enhanced Adaptive Cruise Control: assists the vehicle in maintaining a safe distance from other vehicles by adjusting speed based on more accurate and rapid real-time data

These applications leverage this wheel speed sensor's high resolution, rapid response, and robust performance to enhance vehicle control, safety, and autonomous capabilities.

What challenge does this sensor solve?

Our high resolution wheel speed sensor unlocks new ADAS functions and enhances existing capabilities by overcoming the precision and accuracy limitations of standard wheel speed sensors. This sensor’s increased resolution leads to more accurate vehicle control and improved system efficiencies, paving the way for next-generation vehicle safety and automation. With its robust and reliable design, this sensor enables OEMs and Tier 1 suppliers to explore and new ADAS/ADS capabilities with confidence.

How does the high resolution wheel speed sensor improve over older products?

• Higher Resolution: standard wheel speed sensors provide 2 pulses per pole pair. In contrast, our high resolution sensor offers two programmable options, delivering either 4 pulses per pole pair or 8 pulses per pole pair.
• Enables New and Enhanced ADAS/ADS Capabilities: our high resolution wheel speed sensor not only enables new Advanced Driver-Assistance Systems (ADAS) and Automated Driving Systems (ADS) capabilities, but also enhances existing functionalities that utilize wheel speed and direction data. This sensor provides greater accuracy and faster response times to critical vehicle safety systems, such as anti-lock braking systems (ABS), electronic stability control (ESC), and traction control systems (TCS).

What is TE Connectivity's development approach for custom sensors?

Drawing on over two decades of extensive expertise in designing wheel speed sensors and connector technologies, TE Connectivity provides customers with comprehensive sensor solutions tailored to their needs.

TE’s development methodology for our high resolution wheel speed sensor is deeply rooted in a commitment to meeting customer needs through a lean, set-based design process. This approach maintains flexibility and expansiveness in design choices and requirements early in the development phase, allowing the incorporation of real-time customer insights and feedback. As the project progresses, the focus is systematically narrowed to ensure the final design is technically robust and ideally suited to the rigorous demands of its application environments.

To meet stringent application requirements, this sensor undergoes rigorous, highly accelerated stress tests, along with design validation and production validation tests. A customized leak tester meticulously inspects each sensor, effectively managing potential leaks and adherence to the highest standards of quality and reliability, providing consistent excellence for our customers.

Our commitment to quality is further demonstrated in our production processes, featuring fully automated, VDA-audited manufacturing lines equipped with AI vision systems. These systems provide defect-free, high-volume production. Comprehensive traceability is maintained throughout the manufacturing process, from injection molding to final assembly, adhering to the strictest quality standards. TE Connectivity’s attention to detail, combined with robust testing and validation protocols, enables our high resolution wheel speed sensor to not only meet, but surpass the demanding performance standards required in modern automotive applications.