Intelligent Vehicle Redundant Architecture Design and ADAS Redundancy Strategy Research Report, 2025-2026

Research on Redundant Systems: Septuple Redundancy Architecture Empowers High-Level Intelligent Driving, and New Products Such as Corner Modules and Collision Unlock Modules Will Be Equipped on Vehicles.

With the improvement of intelligent driving levels and the upgrading of vehicle systems towards intelligence, Chinese new energy passenger cars are required to have increasingly high overall vehicle safety.

In terms of functional safety, vehicles are not only required to accurately detect and identify obstacles but also to have fault self-diagnosis capabilities. When a system fault is detected, immediate measures must be taken to ensure driving safety. In addition, vehicles need to assess the risks of intelligent driving in real time according to environmental information and vehicle status, and take corresponding measures to reduce risks.

Meanwhile, the development of chassis-by-wire technology, drive integration, and domain controller integration has also put forward higher requirements for vehicle safety. Vehicle redundancy design needs to cover all systems, and hardware backup is still the main approach currently.

Chassis System: Upgrading towards Intelligence, and Requiring High Redundancy

As a safe and reliable operating carrier for automobiles, chassis system technology is upgrading towards intelligence. Through mechatronic transformation and integrated system control, it enables in-depth collaboration and rapid response of various subsystems, supporting high-level intelligent driving, and electrified and intelligent development of new energy vehicles. Against this background, the level of vehicle functional safety has also increased accordingly. The chassis system of electric vehicles requires high redundancy, currently focusing on steer-by-wire, brake-by-wire, and active suspension:
Steer-by-wire: Include rear-wheel steer-by-wire, front-wheel steer-by-wire, feel simulation unit, and corresponding redundancy control;
Brake-by-wire: Include Two-box, One-box, EMB, and corresponding redundancy control and decoupling technology;
Active suspension: Include continuous damping control (CDC), air springs, full electric active suspension, and full hydraulic active suspension.

Steer-by-wire has been basically separated from mechanical steering. Its control signals may come from the chassis domain controller, intelligent driving system, or the driver's direct operation of the steering wheel. Therefore, redundancy design is a standard configuration for steer-by-wire. When separated from the driver and direct mechanical intervention, the redundancy system provides backup or certain functions, or optimizes the performance of intelligent features.

Bosch Huayu's latest 48V full-domain steering solution integrates a worm gear by-wire upper steering solution and rear-wheel steering. The new-generation 48V direct-drive steer-by-wire system achieves a breakthrough in chassis handling performance through dual technological innovations:
Can provide a maximum output torque of 15.5 Nm;
Torsion bar-free direct-drive structure improves upper steering rigidity and enhances steering precision;
Reduces turning radius to improve driving comfort;
Cooperates with the braking system to achieve in-place steering;
After the front steering system EPS fails, the rear-wheel steering can serve as a temporary steering backup.

Meanwhile, the HE Platform-based dual redundancy design of this solution meets the requirements of L3 and above high-level intelligent driving. It adopts a full redundancy architecture of dual controllers + six-way motors, with backup systems for power supply, communication, and actuators. Even if the main system fails, the backup system can take over within milliseconds to ensure uninterrupted steering. This solution will be mass-produced in customer projects by 2026.

The brake-by-wire system also eliminates the mechanical connection between the brake pedal and the brake. It collects the driver's braking intention with pedal sensors or receives braking requests from the intelligent driving controller via the vehicle communication network. Then, the brake electronic control unit (ECU) processes the electronic signals and controls the brake actuator to output braking force.

By brake actuator, brake-by-wire systems can be divided into electro-hydraulic brake (EHB) and electromechanical brake (EMB).

Based on the traditional hydraulic brake system, EHB replaces some mechanical components with electronic devices and uses brake fluid as the power transmission medium. It also has a hydraulic backup braking system and is currently the mainstream technical solution. According to the level of integration, EHB is divided into Two-box and One-box technical solutions.

EMB replaces the master cylinder hydraulic system with four wheel-end calipers driven by motors. While retaining the advantages of the EHB system, it further releases the layout flexibility of brake system components and simplifies the process and cost of vehicle assembly and later maintenance. However, EMB still has many technical difficulties to overcome, and its redundancy design is particularly complex. Currently, the mainstream brake-by-wire system solution is the mutual redundancy of front-axle EHB and rear-axle EMB, also known as the hybrid brake-by-wire system (HBBW). Chinese suppliers such as Bethel Automotive Safety Systems, LeeKr Technology, and Trugo Tech have launched their self-developed solutions, but few have been equipped on vehicles.

Leapmotor D19 adopts Continental's MK C2 brake-by-wire system (EHB One-box solution), which uses a dual-axle hydraulic braking system and integrates electronic parking brake (EPB). At the software level, it includes enhanced functions such as ABS (Anti-lock Braking System), TCS (Traction Control System), and ESP (Electronic Stability Program), and is equipped with intelligent actuators that can be matched with separate functional braking software.

The MK C2 braking system is more compact in size, lighter in weight, and more cost-effective, and has better performance than the previous generation product. The MK C2 can still maintain more stable performance in the event of a failure. In addition, the MK C2 can be equipped with a HAD expansion module to upgrade to the MK C2 HAD system, which can support braking redundancy control for L2+ and above intelligent driving scenarios.

Drive System: Evolve towards Distribution, and Hub Motors/Corner Modules May Become the Ultimate Form

With the improving performance of drive motors and their control systems, a single centralized drive (front/rear single motor) can no longer meet intelligent requirements. The distributed multi-motor drive system (directly integrating the drive motor into the wheel or wheel rim) has emerged as the times require. On the one hand, the distributed motor system can be deeply coupled with the intelligent chassis to achieve performance improvement and configuration innovation. On the other hand, with the further development of new energy vehicle technology, multi-motor drive systems tend to evolve towards more precise, more intelligent, and more efficient:
Dual-motor distributed drive: Tend to adopt a coaxial dual-motor layout to improve the precision of torque vector control and further reduce energy consumption;
Three-motor four-wheel drive: Optimize the layout of the front axle motor (e.g., integration into the front axle), reducing the mechanical loss of the drive shaft, and improving power transmission efficiency;
Four-motor four-wheel drive: Combine AI algorithms (such as machine learning) to achieve predictive torque control (e.g., adjusting torque by predicting road conditions in advance), further improving handling and safety. Moreover, with the popularization of hub motors (such as hub motors of BYD Yangwang U8), the reducer will be eliminated, further shortening the power transmission path and improving efficiency.

Wheel-side motors and hub motors are two important technical routes for distributed drives. Wheel-side motors have lower engineering design difficulty, and Dongfeng has taken the lead in equipping models in the passenger car market; while hub motors still need breakthroughs in engineering technology, and large-scale mass production and application in passenger cars are not yet mature. Currently, only BYD has launched hub motors and equipped them on Yangwang models.

However, the hub motor version of Dongfeng eπ007 has completed declaration and will become China’s first production model with four-wheel hub motors. The car carries four hub motors produced by Shanghai Auto Edrive Co., Ltd., with a maximum power of 100 kW per motor and a comprehensive system power of 400 kW. Compared with traditional drive forms, hub motors eliminate mechanical transmission components such as drive shafts and differentials, which can reduce mechanical loss by about 30% and lower the overall vehicle maintenance cost.
The four-wheel independent motor layout can achieve precise torque distribution, reducing the turning radius by 10%-15%, and support millisecond-level power response;
The optimized chassis layout releases more space, which helps improve battery capacity and riding comfort;
The energy recovery system can also achieve four-wheel independent adjustment, increasing the recovery efficiency by about 25%.

In addition, currently technical maturity of the four-wheel full EMB is not high. Problems such as motor heat dissipation, braking force distribution, control algorithms, and high costs are difficult to solve, and mass production and installation cannot be achieved in the short term. Therefore, the full EMB system tends to be integrated with hub motors, taking the integrated corner module route, which can be adapted to skateboard chassis and intelligent driving.

The corner module integrates four systems: drive (hub motor/wheel-side motor), braking (brake-by-wire/EMB), steering (steer-by-wire/four-wheel independent steering), and suspension (active suspension/air spring) into a single module, which is connected to the vehicle body via standard interfaces to achieve four-wheel independent control (4WID-4WIS) and full-scenario movement capabilities (in-place steering, lateral translation, diagonal driving, etc.).

Vehicles driven by distributed by-wire corner modules play a role in various fields and scenarios, solving the power failure and special path planning problems of vehicles driven by traditional chassis. After the failure of a single electric power unit, redundant drive is achieved through torque redistribution.

At present, the corner module technology has entered the initial stage of industrialization from theoretical exploration. Chinese and foreign suppliers such as Schaeffler, Baolong Automotive, Zhejiang Shibao, and Tongyu Automotive plan to mass-produce corner modules from 2025 to 2027. In terms of application scenarios, low-speed autonomous vehicles and special vehicles will be the first to use them, and passenger cars are expected to be gradually equipped after 2026. Currently, automakers such as Huawei, IM Motors, BYD, Geely, and SAIC are working to deploy corner module drive technology.

For example, the core innovation of Huawei's corner module solution lies in highly integrating the control functions of each motor into a single wheel-side controller, which significantly reduces the number of control chips and independent controllers. Through a unified communication interface, power battery interface, low-voltage battery interface, and multiple current output interfaces, it enables centralized power supply and control of drive, braking, steering, and suspension motors. It also adopts a dual-control chip architecture (e.g., one controls the drive and suspension motors, and the other controls the braking and steering motors), with mutual monitoring and fault tolerance capabilities). When the braking control chip fails, the drive control chip can instruct the drive motor to output reverse torque to achieve braking redundancy.

Collision Unlock: Redundant Module CPM Solves the Problem of Difficult Unlocking of Electronic Door Handles After Collision

There is also CPM (Collision Unlock Redundancy Module), a unique safety system of Huawei, used for vehicle unlocking in severe collision accidents. Simply put, when a vehicle collides, it automatically unlocks all doors and the trunk to ensure that passengers and rescuers can enter and exit quickly. It integrates Huawei's collision detection algorithm, redundant hardware, and real-time monitoring to create a double insurance mechanism.

CPM adopts an independent power supply design, and each door is equipped with a CPM to ensure that each door can be unlocked successfully in any collision scenario. Moreover, CPM is seamlessly integrated with other safety functions, such as AEB (Autonomous Emergency Braking) and fatigue monitoring. When AEB is triggered but the collision is not avoided, CPM can realize pre-collision unlocking; on the contrary, collision data will be fed back to the AEB algorithm to optimize future responses.

According to internal tests, the unlocking success rate of CPM in a frontal collision at 100km/h is 100%, consuming an average time of 0.15 seconds. Currently, the full range of the AITO M8 BEV version, SAIC H5, LUXEED R7, and S7 are equipped with CPM.

In terms of suppliers, in 2025, Aptiv launched a similar product - Crash Power Module (CPM). Once the vehicle collides, it can respond quickly at the microsecond level, immediately activate the redundant unlocking function, and realize the simultaneous unlocking of all doors such as front and rear door locks, door handle locks, and child locks through collaborative design. Even if the vehicle unfortunately encounters a power failure, its independent power module can still work stably to provide sufficient energy for door unlocking, ensuring the unlocking function is foolproof.

The rise of CPM directly responds to the public's deep concern about the safety hazard of door locking of new energy vehicles (especially those with electronic door handles) after severe collisions. Although this technology has now penetrated from high-end models to models above RMB150,000, it has no cost advantage compared with conventional solutions such as configuring mechanical handles. Therefore, CPM will not be mass-produced on a large scale in a short time. However, in the future, with the reduction of costs, the increase of equipped models, the maturity of the supply chain, and the higher safety requirements for high-level intelligent driving, the CPM market will show an upward trend. ResearchInChina predicts that China’s new energy passenger car CPM market will be value at over RMB1 billion in 2030.

Implementation of L3 Conditional Intelligent Driving Accelerates, and Redundancy Requirements Cover All Vehicle Systems

According to the national standard Taxonomy of Driving Automation for Vehicles, L3 is conditional intelligent driving. In specific scenarios (such as highways), the system can fully take over driving tasks and independently complete lane changes, overtaking, and other operations, and the subject of responsibility shifts from humans to vehicles.

Therefore, L3 conditional intelligent driving has high requirements for vehicle safety. Redundancy requirements cover all systems such as drive, braking, steering, perception, computing, communication, and power supply, ensuring that when a certain system fails, the vehicle can quickly take measures to ensure driving safety.

In December 2025, China's first batch of L3 conditional intelligent driving models officially obtained access permits. The ArcFox αS6 and Changan Deepal SL03 will soon pilot on-road use in designated areas of Beijing and Chongqing respectively, marking implementation of L3 conditional intelligent driving in China's passenger car market. Automakers such as Li Auto, BYD, XPeng Motors, and Xiaomi Motors are also vigorously carrying out road tests of L3 conditional intelligent driving models and promoting the road test process of their L3 models.

Please Note: PDF E-mail from Publisher purchase option allows up to 10 users and does not allow printing or editing. This functionality will require a Global Site License. Show more