Sensor Fusion Expanding in Step with Advancing Vehicle Sophistication

An accelerating need to enable automated-driving and efficiency-enhancing features is driving sensor-fusion innovations.

Deriving the maximum performance and efficiency from the proliferating number of vehicle sensors is driving sensor-fusion development trends. (TE Connectivity)

When drivers of passenger vehicles change lanes, brake at stop lights, or accelerate on the highway, they’re probably not thinking about sensors. Sensors monitor, regulate and alert on changes in fluid and component conditions, such as tire pressure, fuel and oil levels and engine temperatures. They also report on the position of motor components, wheel speed and antilock braking systems as well as monitor internal and external air temperature, helping to maximize passenger comfort.

For vehicles employing the latest ADAS/AV technology, there may be from 60 to 100 onboard sensors, even if the vehicle has a conventional IC powertrain. (TE Connectivity)

The typical non-electric vehicle now is fitted with between 60 and 100 sensors, with 15 to 30 dedicated to managing the engine. Commercial trucks have up to 400 sensors, with up to 70 allocated to engine management.

The shift toward ADAS and automated driving is stimulating unprecedented demand for sensors. Future generations of EVs, particularly those equipped with autonomous or semi-autonomous functionality, may have two to three times the number of sensors as their comparable predecessors. What’s more, the emergence of software-defined vehicles (SDVs) is set to further impact market demand, as they enable a new service delivery model. Instead of hardware determining the features a vehicle can offer, manufacturers will build basic, mid-level, and luxury vehicles with pre-integrated sensor-enabled functionality that can be turned on and off with software, encouraging standardization across the industry.

But that’s not all. The expansion of autonomous capabilities extends to a variety of vehicle types, regardless of the power-source technology. Among these, hybrid vehicles, combining both ICE and electric propulsion and fitted with automated-driving features are likely to have the most significant sensor content. To support these industry advancements, original equipment manufacturers (OEMs) are pivoting from domain-based to zonal electrical architectures, which are homogeneous and bus-based.

Maximizing efficiency with sensor fusion

The more sensors a vehicle has, the smarter it can be. However, sensors take up space and become increasingly expensive as they offer greater functionality or higher performance. As a result, the solution for basic and mid-level vehicles is not always to deploy more sensors or the best ones – but to ensure they address the job at hand most effectively. Luxury consumers, on the other hand, may be willing to pay more for a vehicle with advanced sensor solutions that deliver a higher level of safety, comfort and convenience.

The methodology of integrating multiple sensors into one package or combining the output data of multiple sensors is referred to as sensor fusion. The goal of sensor fusion is to eliminate redundant packaging to minimize system cost or to combine the outputs of various sensors to achieve insights or decision-making abilities that would not ordinarily be possible with isolated sensor data.

While homogenous technologies can be easily integrated, sensors may use different substrates, making it an engineering challenge to combine them. For example, sensors on silicon substrates are not easily integrated with those on silicon-carbide or gallium arsenide substrates. To address this, component manufacturers are exploring new ways to develop multifunctional sensors that deliver added value, optimize the use of space and reduce costs. As an example, the market now offers an integrated module that merges temperature and humidity sensors, enabling a vehicle HVAC system to automatically activate windshield defogging and wiper systems.

Sensor fusion also refers to using sensors, high-speed data connectivity, artificial intelligence and machine learning to provide situational awareness and act on changing environmental and operational conditions. For SAE Level 2 to Level 5 automated driving functionality, sensors help enable varying levels of automation. Lidar, cameras, radar and vision technology facilitate vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2X) communications, increasing process efficiency and reducing the need for sensors to 30 or fewer. Fully autonomous vehicles use sensor fusion to collect and integrate data, recognize patterns and automate a controlled response, such as determining the position and speed of a vehicle and swerving or braking suddenly to avoid a pedestrian crossing in front of the vehicle.

Exploring alternative sensing technologies

Vehicle-to-vehicle (V2V) and vehicle-to-everything (V2X) communications are another consideration in onboard sensor usage. (TE Connectivity)

In addition to leveraging sensor fusion, OEMs and system suppliers are exploring the use of alternative sensing technologies to further reduce costs. Technologies using Eddy Current and xMR (magnetics) are emerging as potential alternatives for resolvers, a passive transformer technology traditionally employed for measuring rotary position.

The adoption of these alternatives will primarily be evaluated based on their cost-effectiveness relative to performance. Depending on the end application and performance requirements, these solutions may be adequate and, as a result, cannibalize existing business. For example, in systems where a secondary eMotor serves as a backup, the performance requirements may be lower than for the primary motor. In such cases, opting for a sensor technology that presents a more cost-effective solution, even with a slightly lesser performance, could represent the better strategic and economical choice.

Sensor-fusion development isn’t exclusive to passenger and commercial vehicles; for this Volvo automated hauler, sophisticated sensing assures safety and reliability. (Volvo)

High-resolution wheel-speed sensors have four times the resolution of legacy wheel-speed sensors. Improved resolution increases vehicle-position accuracy in areas where GPS is unavailable and supports enhanced ADAS features such as lane keeping, lane departure and vehicle positioning. The improved accuracy facilitates quicker updates on vehicle movement, aiding in maneuvers such as automated parking in tight spaces. When it comes to eBraking, systems historically have been hydraulic-based, offering wet-wet braking capabilities. However, by transitioning from pressure to force sensors, OEMs can enable full-dry electronic braking systems, which provide increased responsiveness.

Digital sensors to dominate

Vehicle architectures also are evolving to reduce power consumption and extend the range of EVs and autonomous vehicles. For example, analog sensors that were connected to electronic control unit microprocessors or circuitry and simply turned functionality on and off have gone by the wayside. With bus-based architectures, digital outputs capitalize on massive bandwidth to enable more functionality and ultra-fast response times. In addition, they are easier to plug in and plug out to reduce power consumption. As a result, digital sensors will predominate with new SDV architectures.

The development pace in the passenger vehicle market is advancing at lightning speed: from ICE to EV and from driver-assistance to high levels of automated driving. As the pace of innovation accelerates, the focus will continue to shift both to sensor fusion and alternative sensor technologies as they play an invaluable role in bringing new and advanced functionalities to market.

Trailblazing OEMs undoubtedly will work to develop and trial new technologies that then become mainstream. To make that happen, they will lean heavily on the expertise of component manufacturers to solve challenges, define business and technical requirements for new applications and develop sensor solutions that meet those requirements. With thoughtful expertise and a little clever engineering, sensor fusion will help to create increasingly cost-effective, high-performance solutions that drive innovation in the next generation of vehicles.

Lamar Ricks is the Senior Director and Chief Technology Officer for Transportation Sensors in TE Connectivity’s Sensors Group. In his role, he is responsible for the strategic direction of global engineering, product development and innovation for sensor solutions serving Automotive and Heavy-Duty Vehicle applications. He has 30+ years sensors industry experience with varying technical leadership roles including sensing technology research & development, mixed signal IC and ASIC design, program management, as well as product and platform developments to serve various industries including Automotive, Medical, Industrial, AD&M, Factory Automation, Oil & Gas and Test & Measurement. Lamar has 45+ issued sensor-related patents and holds a Bachelor of Science in Electrical Engineering (BSEE) from Northern Illinois University.