Redundant system research: the last line of defense for smart cars

Zoss Automotive Research Institute released the "2023 China Advanced Driver Assistance Redundancy System Strategy Research Report".

Redundant design, also known as redundancy design technology, refers to adding one or more functional channels, working elements or components that perform the same function in the key areas where the system or equipment plays a key role in completing the task, so as to ensure that when this part fails, the system or equipment can still work normally, reduce the probability of failure of the system or equipment, and improve system reliability.

As the level of assisted driving increases, the driving subject gradually changes from the driver to the vehicle system. In order to ensure that it is always in operation, a redundant system is essential. In the future, when L3 and above assisted driving is achieved, a redundant system will become standard.

At present, the redundancy scope of advanced assisted driving mainly includes perception and positioning redundancy (environmental monitoring), controller redundancy (brain), actuator redundancy (braking, steering), communication redundancy (control information transmission), and power supply redundancy (support failure degradation).

Scope and mainstream methods of automotive advanced driver assistance redundant systems

Source: Public information compilation

At present, most models with high-level driving assistance functions such as NOH, NGP, and NOP are equipped with fully redundant systems, such as Great Wall Wei Mocha, NIO's ET series models, Ideal L8/L7Max versions, and Volvo EX90.

Great Wall Motors, whose department responsible for redundant systems is Coffee Intelligence, released six redundant systems in 2020, including perception redundancy, controller redundancy, architecture redundancy, power redundancy, braking redundancy, and steering redundancy, and launched the first Wei brand Mocha in May 2021.

Perception redundancy adopts a multi-source heterogeneous sensor solution, L+R+V fusion;

Control redundancy uses dual controllers, which operate all the time and back up each other;

Braking redundancy uses a Bosch ESP+iBooster combination;

Steering redundancy application The third-generation intelligent steering product developed by Great Wall Motor's Honeycomb Steering has dual-winding motors, dual motor position sensors, dual CPUs, and dual controllers;

Communication redundancy adopts a dual communication architecture with three independent physical communication links that support each other;

The power supply redundancy adopts a "double insurance" design with dual power supply and dual circuits.

Great Wall Motors' six redundant systems

Source: Great Wall Motors

In November 2022, Volvo released its pure electric flagship SUV EX90, which is its first mass-produced model equipped with a safety redundancy system and is expected to be launched in the Chinese market in mid-2024.

Perception redundancy: the cabin uses a sensor solution of lidar + millimeter-wave radar + camera + ultrasonic radar. The lidar is provided by Luminar and has a detection range of up to 250 meters. The cabin uses the DUS driver perception system for the first time, which consists of two in-car cameras + a capacitive steering wheel.

The controller is redundant and equipped with two parallel collaborative computing platforms, equipped with NVIDIA DRIVE Orin and NVIDIA Xavier chips, with a computing power of 286TOPS;

In addition, the vehicle has been fully redundantly designed in terms of braking, steering, power supply and communication.

With the evolution of smart car architecture, redundant systems are also gradually evolving. For example, in June 2022, Jidu released the JIDU ROBO-01, which is equipped with the self-developed high-level intelligent architecture JET, integrating the electronic and electrical architecture EEA and SOA operating system. Its cabin-driving fusion backup solution is based on the Qualcomm 8295 chip with up to 30 TOPS AI computing power, supporting intelligent driving redundancy. When encountering extreme situations where intelligent driving fails, the smart cabin can take over the driving task in the first time and allow the vehicle to park safely.

As for suppliers, foreign suppliers have more comprehensive redundancy designs. For example, Bosch:

The perception module redundancy adopts ultrasonic sensor + millimeter wave radar + camera + lidar multi-sensor redundancy solution;

The redundant positioning module is a redundant positioning solution consisting of absolute positioning based on satellite signals and relative positioning based on road features.

The decision module is redundantly configured with two sets of core computing units (i.e., domain controllers);

The execution module design redundancy covers the steering system, braking system and engine management system;

The redundancy of the braking system adopts three solutions: iBooster+ESP, IPB+RBU, and DPB+ESP;

The steering system redundancy solution uses a wire-controlled steering system equipped with two motors, two power supplies and two windings.

Bosch brake system redundancy design solution

Source: Bosch

At the same time, domestic manufacturers are also actively deploying redundant systems. For example, Jingwei Hirain deployed redundant EPS (electric power steering controller) for autonomous driving L2-L4 in August 2022, and actively developed R-EPS with full redundant technology to meet the needs of autonomous driving L2-L4.

Hirain Functional Safety Solutions