Lianchuang's research and breakthroughs in key technologies for wire-controlled chassis

Editor's Note: On May 27, 2022, the 2022 Automotive Intelligent Chassis-Cloud Forum hosted by Gasgoo was held as scheduled. Dr. Luo Laijun, Chief Engineer of Lianchuang Automotive Electronics Co., Ltd., was invited to attend and deliver a keynote speech on "Research and Breakthrough of Core Key Technologies of Lianchuang's Wire-Controlled Chassis". Combining industry trends, Dr. Luo comprehensively analyzed the development path of Lianchuang Automotive Electronics' wire-controlled chassis from four aspects: Lianchuang's corporate development, wire-controlled steering, wire-controlled braking, and chassis domain control key technology research. The event was full of practical information and was well received by nearly 100,000 online viewers!

1. Lianchuang Automotive Electronics is determined to develop independently

Lianchuang Automotive Electronics Co., Ltd. was established in 2006. It is a technology innovation company focusing on the development of intelligent connected vehicle control systems. The company has been deeply engaged in the three core business areas of intelligent chassis, intelligent driving, and digital networking, breaking the "bottleneck" technology monopoly of intelligent connected vehicles and injecting Chinese wisdom into the development of intelligent connected vehicles.

2. Lianchuang Automotive Electronics Steer-by-Wire - Fourteen years of independent research and development, five generations of products, continuous iteration, and leading breakthroughs

Lianchuang is the earliest independent enterprise engaged in brushless electric control units. In 2012, Lianchuang launched the first mass-produced brushless motor steering controller in China. After years of accumulation, there are three generations of conventional electric steering mass-produced products, with increasingly rich functions, more compact structures, and higher safety levels. Among them, the third generation of electric steering is the first domestic electric steering product that meets ASIL D requirements. In addition, Lianchuang is also accelerating the layout of future-oriented wire-controlled chassis applications, providing customers with full-scenario applications that meet L1-L4 intelligent driving lateral control and in-depth EPS control solutions with soft and hard decoupling and modularization.

The market share of domestic brands ranks first. As the earliest domestic company to produce independent electric steering controllers, Lianchuang has shipped more than 4 million steering controllers and PPKs. It has a complete industrial ecological chain, and is engaged in both passenger and commercial vehicles. It ranks first among domestic brands in terms of market share! This year, under the background of the industry's chip shortage, Lianchuang Automotive Electronics strives to achieve 2 million units of shipments this year, and it is expected to exceed 5 million units by 2025.

Full-scenario unmanned driving applications. As the wave of intelligence is coming, new tracks and new species are constantly emerging, and the application scenarios of wire-controlled chassis control are becoming more and more extensive. Lianchuang Automotive Electronics has deployed redundant steering and wire-controlled steering based on redundant steering. Lianchuang Automotive Electronics' wire-controlled steering is a full-scenario unmanned driving application, and has achieved full-scenario application in unmanned logistics vehicles, skateboard chassis, and commercial vehicle autonomous driving.

The first self-branded redundant EPS product put into practical use. The fourth-generation high-output fully redundant EPS system leads the Robotaxi track. The overall technology is all based on mass-produced industrialized products. The motor has perfect functions and high cost performance. The software supports terminal OTA refresh. The system, controller, and sensor structure all have redundant architectures, and ISO 26262 LoA ASIL D is less than 10 FIT.

The first demonstration of a steer-by-wire prototype by a Chinese brand. The fifth-generation steer-by-wire system adds a road-feel feedback system based on redundant steering, eliminates the traditional mechanical connection device, and truly meets the requirements of intelligent driving levels above L3 and L4. At the end of 2020, the first demonstration of a steer-by-wire prototype by a Chinese brand was realized.

Five major functional innovations provide a safe and reliable driving experience. The variable transmission ratio can give the driver a more reliable steering feel during rapid steering; the steering wheel is silent, and the steering wheel can remain stationary when it is not needed, but the vehicle can steer normally. When the driver takes over, the steering wheel steering function can be provided at any time, allowing the driver to take over the vehicle steering function without any hindrance; the road feel simulation allows the driver to truly feel the actual situation of the road, and even feel the impact of any small stone on the road on the steering; the joystick control enriches the feasibility of the steering arrangement of the vehicle after the steering wheel is removed; the large screen interaction, in conjunction with the ADAS system, can achieve advanced autonomous driving, laying the foundation for the ultimate realization of L5 level fully autonomous driving.

Fully redundant architecture, high-level functional safety, fully meet the personalized needs of customers. Lianchuang Automotive Electronics's wire-controlled steering is a fully redundant architecture, including motors, power supplies, communications, controllers, sensors, etc., and this redundancy is not a simple hardware 1+1, but to achieve hardware reliability backup, software security monitoring, and meet the level requirement of FIT value less than 10 in terms of functional safety. At the same time, wire-controlled steering can actually be compatible with the requirements of various sizes of customer groups for redundant steering or wire-controlled chassis, providing cost-effective redundant steering or wire-controlled steering requirements.

3. Lianchuang Automotive Electronics Brake-by-wire - Rapidly breaking through the "bottleneck" technology, a breakthrough in domestic brake-by-wire technology

Currently, Lianchuang Automotive Electronics has three generations of brake products, namely EBS, ABS and ESC-base. EBS/ESC has broken the monopoly of international giants and is leading in China. The next generation IEB under development is benchmarked against the world's first-class level and supports L3+ intelligent driving.

The growth rate of the domestic brands market is the fastest. Lianchuang started researching brake products in 2018, and its shipment growth rate is the fastest among domestic brands. So far, the cumulative sales of ABS/ESC products have exceeded 1 million units. This year, Lianchuang is also striving to achieve a shipment volume of 1.65 million units in the context of chip shortage, and to exceed 4 million units by 2025.

Comprehensive intelligent driving brake-by-wire solution. The TwoBox solution based on mechanically decoupled EBS+ESC realizes mechanical decoupling, and the solution is simpler. The simulator provides pedal feel, the pedal does not sink, and energy recovery does not rely on ESC. The brake redundancy solution based on OneBox hydraulic decoupling and RDU has a simpler layout and lighter weight. The pedal is completely mechanically decoupled and is not affected by basic braking, providing drivers with a better braking experience.

EBS is the favorite of new energy vehicles . After several generations of EBS research and development, the latest generation XBS2C can increase the driving range of new energy vehicles by 10%+. Its pedal displacement sensor is integrated inside the system, making assembly simpler and more reliable; for the worm gear solution, the motor output shaft is integrated with the worm gear, which reduces the volume of parts and gives OEMs more layout options; the built-in pedal feel simulator provides drivers with a more comfortable pedal experience and can also provide a braking intensity of more than 50 bar for 30 minutes.

Hydraulic decoupling, integrated IEB+RDU, assisting L3+ higher level intelligent driving requirements. Based on the TwoBox solution, Lianchuang Automotive Electronics is developing OneBox — IEB (Integrated Intelligent Electronic Booster). This product integrates EBS and ESC, making system control simpler, lighter, and achieving true hydraulic decoupling. At this stage, most mainstream car companies have proposed L3+ intelligent driving requirements. When the braking system is downgraded, it is necessary to consider the design of brake redundancy, and Lianchuang IEB+RDU braking system was born. A set of RDU backup system is connected in series on the original IEB pipeline. When the IEB fails completely, the RDU can provide a braking deceleration greater than 0.64g and can brake 4 wheels at the same time, and can achieve X-shaped left and right pressure adjustment. Lianchuang RDU structural design does not have any additional impact on IEB. Its connecting pipelines are well compatible with IEB, and its parts are more used in ESC, which is relatively lower in cost.

Four major functional innovations provide a more excellent braking experience. Independently developed linear solenoid valves with higher control accuracy. In order to achieve complete hydraulic decoupling, Lianchuang Automotive Electronics insists on independently developing linear solenoid valves with higher control accuracy, and the minimum pressure control can reach 2bar; the product adopts variable frequency motor control, 0.1-16K variable frequency motor control, which can bring faster response and lower noise, the braking lock time can be less than 400 milliseconds, and the boost time from 0 to 50bar is less than 200 milliseconds, with better performance; support the customized development of customers' short-wheelbase models, customized development for short-wheelbase electric vehicles, better suppress the body pitch during braking, and give the driver a smoother braking experience; ROPP solution support, redundant braking can integrate EPB controller, support the removal of P gear lock function ROPP required by the current market.