Virtual ECU：Assistant for Vehicle Failure DiagnosticsVirtual ECU：Assistant for Vehicle Failure Diagnostics
As the integration of circuits in automotive electronic devices continues to advance, modern vehicles are now equipped with hundreds of ECUs. Known as the "driving brain," the ECU is responsible for processing input signals—primarily in the form of analog, digital, and pulse signals—and then outputting them to various solenoid valves, motors, and indicator lights, all of which are closely related to driving safety.
In daily driving, the dashboard reflects a part of the ECU's work results, involving speed odometer, tachometer, fuel gauge, etc., and a variety of indicator lights or alarm lights.
Traditional car dashboards typically include indicators for fuel levels and high/low beam headlights. In contrast, modern vehicle dashboards also feature lights for systems like the Anti-lock Braking System (ABS) and traction control, among others. These indicator lights are closely linked to vehicle failure diagnostics.
History of Vehicle Failure Diagnostics
Before the 1950s, vehicle failure diagnostics relied entirely on the experience of mechanics and simple testing tools, resulting in low efficiency and the inability to accurately identify specific faults. In the 1950s, automotive technology began integrating with electronics, and the ECU, which offered advantages like speed, power, reliability, and low cost, greatly improved vehicle performance in terms of power, comfort, safety, and efficiency. However, the ECU also became one of the most failure-prone components.
As the complexity of electronic control systems in engines increased, single-function diagnostic technologies emerged, but it still struggled to diagnose the full range of faults introduced by the ECU. This led to the birth of the first generation of On-Board Diagnostics (OBD).
Due to the incompatibility between OBD systems used by different manufacturers at that time, in 1988, the Society of Automotive Engineers (SAE) in the U.S. standardized diagnostic functions and interfaces, introducing the second generation of On-Board Diagnostics (OBDII), and mandating its installation in all vehicles (which also helped reduce emissions). In the late 1990s, with the introduction of advanced disciplines such as artificial neural network analysis and wavelet analysis, diagnostic speed and functionality were significantly improved.
China's automotive industry began developing at a later stage. The first national research project in 1977, "Non-Disassembly Vehicle Testing Technology", marked the formal start of China's vehicle failure diagnostics. It wasn't until 2010 that vehicles produced in China were required to be equipped with OBDII. Although related products for vehicle failure diagnostics are becoming more abundant in China, there is still room for improvement in functionality, accuracy, user interface, and ease of operation.
ECU Fault Diagnostic System Workflow
To better understand the current ECU fault diagnostic systems, we need to first explain the workflow:
Step 1: Real-time monitoring of the electronic control system and circuit components during vehicle operation. Based on specific algorithms, the system identifies faults and stores them as Diagnostic Trouble Codes (DTCs) in the vehicle's external non-volatile memory. It also categorizes the fault type and condition, taking appropriate action, such as illuminating the corresponding dashboard warning light to alert the driver.
Step 2: By utilizing the Unified Diagnostic Services (UDS, defined by ISO14229) to read fault code information and perform related operations, the investigation and repair of faults can be completed.
However, with the rapid development of new technologies and processes in the automotive industry, the main issue with vehicle failure diagnostics today is not with the diagnostic system itself. Even though ECU fault diagnostic systems are ready, manufacturers still need to wait for the actual hardware to become available, significantly extending development cycles.
Virtual ECU Fault Diagnostic System
It has become a common practice among leading automotive manufacturers to simulate hardware in the early stages of development, allowing for earlier testing and validation and thus reducing the development cycle. Integrating virtual validation into the development process ensures that products meet basic requirements before production, significantly enhancing development efficiency and overall productivity.
▲Virtual Validation in Development Process
The currently globally recognized automotive embedded software architecture is AUTOSAR (AUTomotive Open System ARchitecture).
▲AUTOSAR Layered Architecture
SkyEye, also known as a full-digital real-time simulation software, is a hardware behavior-level simulation platform based on visual modeling. It provides an ECU virtualization environment for automotive embedded software that meets the AUTOSAR standards, enabling pre-simulation of fault diagnosis systems.
In addition to allowing early verification of fault diagnostics, SkyEye also offers the advantage of executing test cases in significantly less time than actual hardware, making it an ideal tool for automotive R&D teams.
Throughout decades of automotive development, it has been the continuous introduction of new technologies that has driven the industry's upgrade and progress. The integration of virtual ECU technology into the traditional automotive industry is expected to bring a more efficient, reliable, safe, and intelligent driving experience.
Reference
[1] Virtual ECU Development for Vehicle Diagnostics Software Testing using UDS Protocol，IEEE，Shubham Bidkar; S. L. Patil; Pravin Shinde
[2] 一篇易懂的ECU故障诊断指南，汽车电子与软件，糊涂振
[3] 基于UDS协议的汽车电控单元故障诊断服务设计与实现，陈睿智
