Redundant system strategy research: develop towards integrated redundant design
ADAS redundant system definition framework
For autonomous vehicles, safety is the primary premise. Only when ADAS is fully redundant can real safety be ensured. Currently, the redundant design of most OEMs, Tier 1 suppliers and L4 autonomous driving companies is mainly software and hardware backup:
Software: algorithm redundancy, for example, GAC Group’s latest ADiGO PILOT intelligent driving system adopts the AEB function algorithm, the vision + radar fusion algorithm and the vision algorithm real-time redundant verification strategy to maximize the reliability of AEB.
Hardware: reflected in different functional positions. The perception end, decision end, execution end, power supply end, etc. all adopt dual-redundant or multi-redundant design to ensure that when one of the systems fails, another system with the same function can work normally.
Execution redundancy: Fully redundant design of braking and steering systems
Execution redundancy and decision redundancy are the core parts, directly determining whether the vehicle can make correct response at a critical moment. Execution redundancy is often placed in braking and steering systems, and is generally designed as two independent systems with same functions. Decision redundancy is on the brain side. In vehicle EEA, the central computing platform is equipped with two sets of core computing units, and the redundant architecture design concept is adopted at vehicle architecture level, function definition level, system level, etc.
From the perspective of braking redundancy, its characteristics and trends are as follows:
At present, the key product is electro-hydraulic brake system (EHB), and the common redundancy schemes are the mechanical redundancy + electronic redundancy dual fail-safe mode, and adding auxiliary brake modules;
Brake-by-wire system is the future trend, because the electromechanical brake system (EMB) completely abandons brake fluid, hydraulic pipelines and other components of traditional braking systems, and generates braking force by electric motor drive, which improves the response speed, simplifies the structural layout, and enables inherent redundancy capabilities. However, it has extremely high reliability requirements and is difficult to mass-produce and install on vehicles in the short term.
In terms of steering redundancy, its characteristics and trends are as follows:
Currently the electric power steering system (EPS) mainly adopts the dual EPS steering redundancy scheme with two motors, two power supplies and two windings, which is equivalent to two sets of completely independent EPS hardware, which are independent of and backed up by each other, and the overall cost is relatively high;
The steering system is developing from electric power mode to wired-control mode. Steer-by-wire (SBW) system is composed of three main parts, i.e., steering wheel assembly, steering actuator assembly and ECU, as well as auxiliary systems such as automatic fail-safe system and power supply. It offers benefits of quick response, flexible installation method, light weight and high collision safety. SBW system therefore needs to have redundant backup of core components.
Redundant design of steer-by-wire system of NIO NT 3.0 Platform
The steer-by-wire system is used for transmission and control of electrical signals between the steering wheel and wheels. The angle and resistance torque of the steering wheel can be freely designed, with lower delay, more precise control, higher transmission efficiency and more flexible layout.
Fully redundant design with dual power supply, dual communication, dual hardware and dual software. Although there are no mechanical steering columns to connect the steering wheel and wheels, its reliability is 2.2 times higher than common electric power steering systems.
In December 2024, NIO ET9, the first model based on NT 3.0 Platform, acquired the mass production license for steer-by-wire technology from the Ministry of Industry and Information Technology, becoming China's first model carrying steer-by-wire technology.
Integrated redundant design for central computing architecture
With the in-depth application of intelligent connection and autonomous driving technologies, vehicle braking and steering systems are heading in the direction of integration. The central EEA and integrated chassis launched by some OEMs and suppliers combine the braking system, steering system, drive system, etc., and adopt an integrated and fully redundant design concept.
CATL Integrated Intelligent Chassis (CIIC) of CATL (Shanghai) Intelligent Technology Co., Ltd.
CIIC (CATL Integrated Intelligent Chassis) launched by CATL (Shanghai) Intelligent Technology Co., Ltd. is a highly intelligent skateboard chassis, with core features of "upper and lower decoupling, high integration, and openness".
CIIC highly integrates vehicle drive system, brake system, steering system, suspension system, etc. into the physical underbody, and the platform design enables scalable software and hardware;
CIIC-M (middle platform) adopts fully wired-control technology, eliminating the mechanical connection between the brake pedal and ECU, and completely decoupling the upper and lower bodies; meanwhile, it adds software redundancy strategy, safety monitoring, and fault handling mechanism to ensure system safety and robustness.
BYD e4 Platform
BYD's e4 Platform cancels the steering column and brake caliper, and uses the driving-braking-steering three-in-one technology to achieve steering and braking, thereby realizing vehicle-level safety redundancy capabilities.
Equipped with four 220-240kW large motors, it achieves the maximum braking deceleration of 1g and braking through precise motor torque and speed control, coupled with power blade batteries, new silicon carbide motor controller and advanced thermal management technology;
Differential steering technology is used to steer the vehicle. The left and right wheels receive different torques to deflect and thus complete the steering. The minimum turning diameter is 12 meters, and in the 18m pylon course slalom test, the maximum speed is 60km/h.
The e4 Platform features a distributed drive form with four independently driven motors, and it enables basic driving capabilities even if only one motor is working. In addition, the e4 Platform's innovative technology can provide braking and steering dual redundant backup based on existing braking and steering.
Control redundancy: Multi-ECU redundancy is still the mainstream solution, and will develop towards single-chip redundancy in the future
The control system must meet fail-operational requirements to achieve L3 and above autonomous driving functions, that is, after a sensor fails, the vehicle can still perform corresponding functions and complete driving safely. To this end, controlling system will use two or three ECUs, and implant some redundant safety measures on some sensors, or achieve control redundancy by adding chips in the domain controller.
Multi-ECU Redundancy Solution - Dual Computing Platforms of BYD Xuanji Intelligent Architecture
As the main computing platform, Tianxuan cross-domain computing platform integrates the power domain, body domain and chassis domain, and adopts a multi-PCB design scheme for cooperative control of power domain, body domain and chassis domain;
A backup computing platform Tianji is added as backup redundancy. It is connected to the front and rear control domains via dual Gigabit Ethernet for case of need.
Single-chip redundant layout - based on Renesas multi-domain fusion SoC R-Car X5
R-Car X5, Renesas Electronics' the latest generation of automotive multi-domain fusion SoC (using ARM Cortex-A720AE core, meeting ASIL-B to ASIL-D functional safety requirements; 32-core design, CPU computing power up to 1000kDMIPS), supports the safety isolation of multiple domains with different functional safety level requirements, and adopts hardware-based "Freedom From Interference (FFI)" technology. This hardware design achieves the isolation of critical safety functions (such as brake-by-wire) from non-critical functions, and critical functions that are considered to be related to safety can be assigned to their own independent and redundant domain. Each domain has its own independent CPU core, memory, and interface, thereby preventing potential catastrophic failures in the vehicle when hardware or software in different domains fails.
China ADAS Redundant System Strategy Research Report, 2024
Redundant system strategy research: develop towards integrated redundant designADAS redundant system definition framework
For autonomous vehicles, safety is the primary premise. Only when ADAS is ful...
Smart Car OTA Industry Report, 2024-2025
Automotive OTA research: With the arrival of the national mandatory OTA standards, OEMs are accelerating their pace in compliance and full life cycle operations
The rising OTA installations facilitat...
End-to-end Autonomous Driving Industry Report, 2024-2025
End-to-end intelligent driving research: How Li Auto becomes a leader from an intelligent driving follower
There are two types of end-to-end autonomous driving: global (one-stage) and segmented (two-...
China Smart Door and Electric Tailgate Market Research Report, 2024
Smart door research: The market is worth nearly RMB50 billion in 2024, with diverse door opening technologies
This report analyzes and studies the installation, market size, competitive landsc...
Commercial Vehicle Intelligent Chassis Industry Report, 2024
Commercial vehicle intelligent chassis research: 20+ OEMs deploy chassis-by-wire, and electromechanical brake (EMB) policies are expected to be implemented in 2025-2026
The Commercial Vehicle Intell...
Automotive Smart Surface Industry Report, 2024
Research on automotive smart surface: "Plastic material + touch solution" has become mainstream, and sales of smart surface models soared by 105.1% year on year
In this report, smart surface refers t...
China Automotive Multimodal Interaction Development Research Report, 2024
Multimodal interaction research: AI foundation models deeply integrate into the cockpit, helping perceptual intelligence evolve into cognitive intelligence
China Automotive Multimodal Interaction Dev...
Automotive Vision Industry Report, 2024
Automotive Vision Research: 90 million cameras are installed annually, and vision-only solutions lower the threshold for intelligent driving. The cameras installed in new vehicles in China will hit 90...
Automotive Millimeter-wave (MMW) Radar Industry Report, 2024
Radar research: the pace of mass-producing 4D imaging radars quickens, and the rise of domestic suppliers speeds up.
At present, high-level intelligent driving systems represented by urban NOA are fa...
Chinese Independent OEMs’ ADAS and Autonomous Driving Report, 2024
OEM ADAS research: adjust structure, integrate teams, and compete in D2D, all for a leadership in intelligent driving
In recent years, China's intelligent driving market has experienced escala...
Research Report on Overseas Layout of Chinese Passenger Car OEMs and Supply Chain Companies, 2024
Research on overseas layout of OEMs: There are sharp differences among regions. The average unit price of exports to Europe is 3.7 times that to Southeast Asia.
The Research Report on Overseas Layou...
In-vehicle Payment and ETC Market Research Report, 2024
Research on in-vehicle payment and ETC: analysis on three major application scenarios of in-vehicle payment
In-vehicle payment refers to users selecting and purchasing goods or services in the car an...
Automotive Audio System Industry Report, 2024
Automotive audio systems in 2024: intensified stacking, and involution on number of hardware and software tuning
Sales of vehicle models equipped with more than 8 speakers have made stea...
China Passenger Car Highway & Urban NOA (Navigate on Autopilot) Research Report, 2024
NOA industry research: seven trends in the development of passenger car NOA
In recent years, the development path of autonomous driving technology has gradually become clear, and the industry is acce...
Automotive Cloud Service Platform Industry Report, 2024
Automotive cloud services: AI foundation model and NOA expand cloud demand, deep integration of cloud platform tool chainIn 2024, as the penetration rate of intelligent connected vehicles continues to...
OEMs’ Passenger Car Model Planning Research Report, 2024-2025
Model Planning Research in 2025: SUVs dominate the new lineup, and hybrid technology becomes the new focus of OEMs
OEMs’ Passenger Car Model Planning Research Report, 2024-2025 focuses on the medium ...
Passenger Car Intelligent Chassis Controller and Chassis Domain Controller Research Report, 2024
Chassis controller research: More advanced chassis functions are available in cars, dozens of financing cases occur in one year, and chassis intelligence has a bright future. The report combs th...
New Energy Vehicle Thermal Management System Market Research Report, 2024
xEV thermal management research: develop towards multi-port valve + heat pump + liquid cooling integrated thermal management systems.
The thermal management system of new energy vehicles evolves fro...