Automotive Electronics Testing for Safe, Reliable Vehicles

Automotive Electronics Testing for Safe, Reliable Vehicles

Key takeaways:

• Software testing has become a major component of automotive electronics testing because most critical driving functions are controlled by software.
• Automotive vehicle and electronic component manufacturers must follow a large number of international and industry standards in all their design, fabrication, and testing.
• The testing of advanced driving assistance systems (ADAS) and autonomous driving applications requires simulators for several critical subsystems.

In modern cars, when you turn your steering wheel, press the brake pedal, or just switch on a light, your actions are converted to electronic signals that are sent to their respective subsystems and electronic control units (ECU) to produce the desired responses in the vehicle.

But even a minor interference or electrical problem in any of ECU circuitry can result in abrupt stops, unexpected changes in some subsystems, or, in the worst case, a traffic accident.

Automotive electronics testing is the key to keeping all this complexity functioning smoothly for years. In this article, you'll get an overview of the various aspects of automotive electronics testing.

What is automotive system testing?

Automotive system testing evaluates all aspects of a vehicle like:

• operational testing and safety
• electrical safety
• electromagnetic compatibility
• environmental durability

All these aspects are standardized by various organizations so that the entire automotive industry uses the same vocabulary and business norms. In the next section, we'll look at some of these standards.

What are the standards for automotive electronics?

Many standards have been published by official bodies and industry associations to address different aspects of automotive electronics. Here are some of the important standards that automotive electronics testing must pay attention to.

Standards by the International Organization for Standardization (ISO)

We first look at some key ISO standards governing automotive electronics and their testing by original equipment manufacturers (OEMs):

• ISO 26262: The ISO26262 standards govern the functional safety testing of automotive electrical and electronics components at the system, hardware, and software levels.
• ISO 11451 and 11452: These two standards test the immunity of vehicles and automotive components to electrical interference from narrowband radiated electromagnetic (EM) fields in a wide frequency range from 0.01 megahertz (MHz) to 18 gigahertz (GHz).
• ISO 16750: The ISO 16750 series of standards guide the design and testing of vehicle electronics to face environmental conditions covering electronic, mechanical, climatic, and chemical factors.
• ISO 7637: This standard guides automotive electronics testing and design for immunity against electrical disturbances due to conduction, inductive coupling, and capacitive coupling.

Society of Automotive Engineers (SAE) standards

The SAE is an industry consortium that publishes standards for practically every automotive industry subsystem, including electronic control units (ECUs) and advanced driving assistance systems (ADAS). Some of their key standards include:

• SAE J1113: This standard guides the measurement of electromagnetic compatibility (EMC) and immunity to conducted and radiated emissions of automotive electronic components.
• SAE J1211: The SAE J1211 handbook guides the robustness and reliability testing of automotive electronic systems.

International Electrotechnical Commission (IEC) standards

Important IEC standards include:

• IEC 61508: This is a general standard for the functional safety of any electrical or electronic equipment, including automotive equipment.
• IEC 61000: This is a set of standards that describe testing and measurement techniques for EMC and immunity against EM radiation and fast transients.
• IEC 60529: This standard specifies the protection of electronic enclosures against dust, liquids, and access to components in automotive systems.

Other standards

The International Special Committee on Radio Interference (CISPR) publishes many standards that focus on EMC testing and immunity. For example, the CISPR 25 standard ensures that any electronic or electrical sources of radiated emissions inside the vehicle don't interfere with the ability of onboard receivers to receive radio signals for satellite positioning, Bluetooth, Wi-Fi, mobile telecom, and broadcast radio.

What is functional testing of automotive electronics?

Functional testing verifies that automotive electronic components and subsystems are working as per specifications while also carrying out performance testing and meeting safety requirements.

Functional testing encompasses different kinds of evaluations to address all aspects of component operations. It includes:

• Hardware-in-the-loop testing: Real-time simulations create accurate operating environments for testing complex ECUs, systems-on-chip (SOCs), and electronic subsystems.
• Signal accuracy and quality validation: All analog and digital signals are verified as operating within specified thresholds without errors.
• Software regression testing: Software updates and changes to automotive electronic systems are tested to ensure that they haven't broken previously working functionalities.
• In-vehicle communications testing: In-vehicle networking (IVN) systems like automotive Ethernet, controller area networks (CAN), and local interconnect networks (LIN) are checked for reliable data transmissions between electronic components.
• Safety systems evaluation: ADAS functions like cruise control, collision detection, automatic braking, and lane-keeping assist are tested under various scenarios to ensure that their decisions improve the safety of all road users.
• Battery and power electronics testing: A major goal of functional testing is validating the performance, durability, and compliance of power systems, voltage converters, regulators, batteries, battery management systems, and inverters.
• Noise, vibration, and harshness testing: These tests analyze how electronic components behave under different environmental conditions and vibration frequencies to ensure that a vehicle's electronic systems can withstand vibrations and don't contribute to them.
• ECU-level operations: At the ECU level, functional testing can check if the circuitry of electronic subsystems work properly when powered up. A simple classic example is testing the ECU for lighting controls for headlights and signal lights.
• Vehicular-level tests: At the vehicular level, functional testing of electric vehicle battery packs is now a vital step for ensuring the EV delivers on range and safety. For example, the SL1800A regenerative direct current emulator simulates various power sourcing and sinking scenarios for testing high-voltage battery packs.
• Radar and lidar tests: Functional testing of automotive radar and lidar modules using simulated targets is another aspect of automotive testing for ADAS and autonomous driving that is of growing importance.

Let's explore more examples of specific types of automotive electronics tests.

How do environmental tests ensure the reliability of automotive electronic components?

To ensure the long-term reliability of components, environmental tests simulate the harsh conditions that automotive electronic components undergo during their operational lifespans often to 20 years.

These tests expose components to a wide range of conditions covered by the ISO 16750 and SAE J1211. The conditions include a variety of:

• Electrical conditions: phenomena like fast transients, voltage surges, and electrostatic discharges
• Mechanical factors: vibrations with various frequencies, waveforms, and durations
• Climatic conditions: the effects of temperature, salt spray, humidity, and precipitation
• Chemical agents: the effects of agents like engine oil, brake fluid, and antifreeze

Simulating these environmental conditions allows manufacturers to assess how well the components can withstand real-world conditions in the following ways:

• Temperature testing: Electronic components are checked for reliable operations within a specified temperature range based on the target market. It ensures that components can endure those temperatures without damage during storage and regular operation.
• Vibration testing: This evaluates that all vulnerable points like solder joints and connectors can endure prolonged vibrations of different frequencies and waveforms.
• Thermal testing: Electronic components are cycled between extreme temperatures to ensure that expansion and contraction don't damage them.
• Humidity evaluation: This checks the resistance of automotive electronics to moisture-induced corrosion over time that can change electrical behaviors and possibly even cause dangerous short circuits.
• Ingress protection testing: This assesses the protection of component enclosures against water and dust, especially for components that are attached under the hood or externally.

Why is testing the electromagnetic compatibility of automotive electronics important?

Testing the EMC of automotive electronics is crucial to ensure that they operate reliably in their environments without causing or succumbing to electromagnetic interference (EMI).

The justifications for thorough EMC testing include:

• Safety and reliability: Automotive electronics are integral to the operational safety and reliability of vehicles, encompassing critical systems like braking, steering, airbags, and ADAS. EMC testing ensures that these critical systems function as intended without interference, mitigating system malfunctions that could lead to safety issues.
• Regulatory compliance: EMC testing is crucial for meeting global regulatory requirements and standards like CISPR 25 and ISO 7637. Compliance is often also a prerequisite for entering some markets.
• Interoperability: Modern vehicles are dense connectivity environments with multiple wired and wireless technologies like automotive Ethernet, SerDes, Wi-Fi, Bluetooth, 5G, and many more. EMC testing ensures that all of them can operate harmoniously while ensuring the integrity of communications and data exchange between subsystems.
• Consumer confidence: Rigorous EMC testing boosts consumer confidence in the safety, security, and performance of automotive products.
• Performance: EMC testing simulates various electromagnetic conditions to ensure that automotive electronics remain functional and can perform in any electromagnetic environment.
• Prevention of product recalls: By identifying and rectifying EMC issues during the design and testing phases, manufacturers can significantly reduce the risk of expensive product recalls related to electromagnetic interference, safeguarding against financial, legal, and reputational penalties.

What are the challenges in testing advanced driver assistance systems and autonomous driving?

Testing ADAS and autonomous driving presents several unique challenges due to the large number of possible real-world scenarios they must handle. Key challenges include:

• Real-world scenario emulation: The complexity of real-world driving scenarios must be accurately simulated in a controlled testing environment. It's crucial to test the systems across a variety of weather, lighting, terrain, and traffic conditions. Keysight's autonomous drive emulation platform addresses this problem by enabling engineers to simulate realistic road scenarios in the lab.
• Sensor fusion: ADAS and autonomous vehicles rely on an array of sensors like automotive radars, lidars, cameras, and ultrasonic sensors, all working together to perceive the environment. Integrating and ensuring seamless communication and accurate data fusion from these diverse sensors pose significant testing challenges.
• Millimeter-wave radar testing: Testing automotive radars operating at millimeter wave frequencies requires precision high-performance equipment to emulate a radio environment and measure the radar's radio frequency (RF) parameters through over-the-air testing.
• Interoperability and connectivity testing: As autonomous vehicles also include connectivity features like vehicle-to-everything communications, testing must ensure that these systems can reliably communicate with other vehicles, infrastructure, and networks under varying conditions.
• Cybersecurity: With the increased connectivity and complexity of ADAS and autonomous vehicles, ensuring the cybersecurity of these systems against malicious attackers is a significant challenge.

How are in-circuit testing and automated test equipment used in automotive electronic manufacturing?

In-circuit testing (ICT) using inline automated test equipment (ATE) checks for defects in printed circuit board assemblies (PCBAs) of automotive ECUs before they enter the sub-assembly phase. Manufacturing test software provide analytics to improve yield and processes, while reducing retesting.

ICT checks for common defects like:

• solder shorts and other soldering defects, such as "tombstoning" of surface-mount capacitors and resistors
• lifted pins
• missing components on the boards

ICT is conducted as follows:

1. A custom test fixture is designed specifically for each PCBA.
2. Each manufactured PCBA is placed in the ICT machine under its respective fixture.
3. Probes connect to the pins of the board under test.
4. The other ends of the probes are connected to the fixture interface pins via fixture wires.
5. The fixture interface pins talk to the module interface pins.
6. Scripts for test automation activate and deactivate specific electrical paths between the ICT machine and the board to check if specific inputs to the board result in expected outputs.

Using ICT systems like the i3070, an automotive PCBA manufacturer was able to increase the throughput of theirADASboard testing by 10%.

What methods and tools are used to test communication protocols in automotive electronic systems?

A variety of wired and wireless in-vehicle networking systems are used in modern vehicles. Their individual functionality, as well as interoperability with each other, are tested using tools and techniques like:

• Automotive network signal generators: Hardware and software that can generate network protocol signals for automotiveEthernet and serial bus networks, as well as SerDes and other systems, are used.
• Network signal analyzers:Oscilloscopes and software capable of debugging automotive network signals are used for analysis.
• Network compliance testers: Equipment to test end-to-end functionality and standards compliance are used.

Why is software verification important in automotive electronics testing?

Software verification has become crucial because a significant percentage of the behavior of modern vehicles is controlled by thesoftware running on ECU SoCs.

A subsystem ECU in a modern vehicle has to achieve complex functionality by fusing data from multiple sensors, applying complicated decision-making logic to the sensor data, and finally instructing relevant actuators to change the state of that subsystem.

There are anywhere from 100 to 150 ECUs in modern vehicles. The most convenient way to implement so many ECUs is to offload most of their logic to the software code running on the ECU SoCs instead of baking the logic directly into their PCBAs. This also reduces the time to market and allows for future improvements through inexpensive software upgrades instead of costly board replacements.

This trend has been exponentially accelerating in recent years. As a result, embedded software testing has now become a major, if not the most critical, part of automotive electronics testing.

How is cybersecurity relevant to automotive electronics testing?

Another consequence of more software in a vehicle is the increased attack surface for malicious software-based attacks. To counter this, cybersecurity has become a major component of automotive electronics testing.

Automotive cybersecurity preventive and curative measures include:

• formal software verification methods for the most critical portions of the embedded software
• simulating attack scenarios
• generating malicious payloads using automotive protocol-aware exploit tools
• recording SoC metrics and performance to analyze successful exploits that must be defended against

Purpose-built security solutions like Keysight's SA8710Aautomotivecybersecurity test platform and software like BreakingPoint are invaluable in helping manufacturers ensure the safety of their critical systems.

Automotive electronics testing for long-term reliability

In this article, we dove into various aspects of automotive electronics testing. Keysight offers solutions to facilitate every aspect ofautomotive electronics testing, including:

• analysis and modeling tools for power semiconductor devices and modules
• autonomous sensor testing hardware and emulation software
• simulation software for radars and lidars
• in-vehicle network testing software and hardware
• electric vehicle charging and vehicle-to-grid solutions
• electric vehicle battery charging and testing solutions
• software communication and safety testing software
• end-of-line systems for in-circuit testing combined with software for manufacturing test plans and analytics

Contact us for expert guidance on automotive electronics testing of your vehicles or components.

Related use cases:

How to test EV charging conformance

How to validate automotive cybersecurity

How to Conduct C-V2X Hardware-in-the-Loop Testing

Download for further reading:

eBook: Design and Test Solutions for E-Mobility and Autonomous Driving

Application note: Advancing Cluster Testing for High-Density PCBA in Automotive Electronics

Application note: Mitigating Interference in Automotive Radar Systems

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