What Are Adaptive Headlights?

As the global shift toward automated driving (AD) continues, the future of adaptive headlights, or adaptive driving beam headlights (ADB), is quickly coming into focus. Engineers and designers are working hard to identify the best combination of components to satisfy driver needs for safety and visibility.

However, designing and testing for real-world conditions is time-intensive, expensive, and complex. As advanced driver assistance systems (ADAS) permeate more automotive features and increase functionality, engineers must account for an ever-increasing number of scenarios — making physical testing and validation a challenging and complex process.

Physics-based optical simulation solutions can help speed up the process of bringing ADB technology to market and help avoid costly manufacturing mistakes. 

What are Adaptive Headlights and How do they Work?

Available on many vehicles in Europe, Canada, and Japan and recently approved in the U.S., adaptive driving beams are an automotive safety feature that enable headlights to adjust their beam pattern in response to driving conditions. Adaptive capabilities help reveal critical objects such as lane markings, pedestrians, and oncoming cars while avoiding using full high beams that might temporarily blind an oncoming driver.

ADB capabilities rely on perception systems that gather data, underlying software controls that trigger an appropriate response, and advanced headlamp optics that carry out the command. The system uses a camera to detect the position of other vehicles through automated beamforming, controlled by a computer that alters the angle and intensity of the headlights according to conditions. Essentially, the headlights “adapt” to create a light pattern on the fly — optimizing for real-time conditions.

Unlike automatic high beams, which can behave erratically when interpreting oncoming headlights compared to other lights and reflections, adaptive driving beams maintain the central beam, providing excellent visibility ahead while dimming the extremities of the beam "cone" to keep oncoming traffic from getting blinded.

The technology can also widen the beam to another lane in preparation for a lane change and bend the light around corners to help illuminate curves as the steering wheel turns.

Adaptive Headlight Design Challenges

Adaptive headlamps operate in a safety-critical environment and any mistake in the closed-loop sensing-controlling-lighting process can have disastrous consequences. They must meet the regional Department of Transportation, United Nations Economic Commission for Europe (ECE), NHTSA Federal Motor Vehicle Safety Standards (FMVSS) #108, and the Society of Automotive Engineers (SAE) standards for headlight visibility, durability, and reliability. That is why, before being launched commercially, they must be exhaustively tested and proven to respond accurately to every possible real-world situation they will encounter.

Yet it is not feasible for engineers to create multiple sensor-software-optics prototypes, install them on multiple vehicles, and physically test them on different roads, at different hours of the day, and under every possible weather condition. Even if this were physically possible, it would mean an investment of millions of dollars and thousands of road miles.

Fast, physics-based simulation can help engineers overcome these challenges by replicating the physical world with high predictive accuracy. Engineers should consider four challenges when simulating adaptive headlight design, including the optical design of the lenses, thermal analysis of the lens, design of mechanical housing around the lens, and simulating night driving conditions.

Challenge 1: Simulating the Optical Design of the Lenses

To simulate the optical design of the adaptive driving beam lens, the technology must account for the distance and height of the oncoming driver, the reflectivity of the road surface, and even the atmospheric conditions. With this type of complexity at play, it is important that the virtual design space:

• Enable the user to build physically accurate virtual prototypes in real-time — modeling everything from imaging optics to illumination, including stray light analysis and complexities such as a matrix of LEDs.
• Consider optical properties of the material and light sources to simulate propagation from the headlamp and other light sources.
• Incorporate feedback from virtual driving tests to perfect the headlamp’s design and functionality long before constructing a physical prototype.

Challenge 2: Conducting Thermal Analysis of the Lens

Lens design can change based on the vehicle's speed and the driving environment. If the lens gets too hot, it can distort the light's shape and cause the adaptive system to malfunction. The simulation technology must measure the light's intensity and shape based on the designed lens so that the adaptive function works correctly.

Challenge 3: Designing the Mechanical Housing Around the Lens

Mechanical tolerancing and optimization tools such as design for manufacturing (DFM), statistical tolerance analysis, Monte Carlo simulation, and finite element analysis (FEA) are needed to ensure that the adaptive driving beam lens is aligned correctly with the housing. These tools can help to account for variations in the size and shape of the housing, as well as variations in the size and shape of the adaptive driving beam lens.

Challenge 4: Simulating Night Driving Conditions

To accurately test ADB execution, engineers must test performance under every conceivable lighting, traffic, pedestrian, and weather condition present during night driving. Here is where it is critically important to have access to real-time, physics-based optical simulation technology. The technology should:

• Offer an immersive environment for test drivers-in-the-loop simulation or quality review.
• Generate scenarios such as following, passing, or crossing a car in parallel and test them with a keyboard, steering wheel, or driving simulator.
• Facilitate comparisons between different behaviors and light sources — halogen, xenon, or LED.
• Simulate chromatic aberrations caused by the projector lens at the low beam cutoff area.
• Objectively measure the discomfort of the glare generated by the other vehicle's headlamp from a driver's perspective on the de Boer scale and graphically show the glare impact.
• Consider intelligent lighting control laws, such as virtually evaluating and optimizing the headlamp rating according to the Institute for Highway Safety (IIHS) test track or China Insurance Automobile Safety Index (C-IASI) track

The Future of Adaptive Headlight Technology

In today’s dynamic headlamp market, newer features such as adaptive high beams and pixel beam technology must be tested across various parameters. Development is happening at a rapid pace, which requires access to physics-based optical simulation solutions that can help ensure that the first physical prototype is in excellent working condition, is safe and effective before vehicle installation, and significantly reduces dependency on costly, real-world night drives.

Ansys solutions for adaptive driving beam simulations help engineers understand the impact of their design decisions at every stage of the process.

Learn how Ansys solutions help automotive companies virtually perform ADB night test drives on custom test tracks, safely explore dangerous driving situations, and efficiently design ADBs from automatic high beam to pixel beam in this on-demand webinar: Win the Race for new Adaptive Driving Beam (ADB) Territories.