Passenger Car Intelligent Steering Industry Research Report, 2024

Intelligent Steering Research: Steer-by-wire is expected to land on independent brand models in 2025

The Passenger Car Intelligent Steering Industry Research Report, 2024 released summarizes and studies the status quo, installation, suppliers’ layout, supply chain layout, etc. of intelligent steering in the world and China, and predicts the future development trends of intelligent steering.

1. Policies provide continuous support, and standards concerning steer-by-wire are becoming definite.

Since 2023, China has formulated a range of national standards, association standards and other policies for steer-by-wire. From system standards such as technical requirements and test methods for steer-by-wire of commercial vehicles and passenger cars, to component standards for wheel hub/wheel rim motors and steer-by-wire road sense simulators, the standards for steer-by-wire are becoming increasingly definite and perfect.

Take the steer-by-wire road sense simulator as an example: when the driver drives a vehicle, the hand feel is very important to the driver. The road sense transmits the force and road conditions of the tires, road surface, and body to the driver through the steering wheel in real time. Without mechanical connection, the road sense can only be produced by the steer-by-wire road sense simulator. The most important function of a road sense simulator is to simulate and restore the driver's feelings as realistically as possible under different road conditions.

In August 2024, the Institute of Electrical Engineering (IEE) of Chinese Academy of Sciences (CAS) and HYCET EPS System (Jiangsu) jointly took the lead in drafting the CSAE standard 'Fault Injection Test Specifications for Steering Wheel Hand Feel Simulation Controllers of Passenger Car Steer-by-Wire Systems', a standard which filled the gap in this field.

The following table shows the statistics of steer-by-wire standards and policies from 2023 to 2024:

2. Many OEMs are vying to deploy steer-by-wire technology which is expected to be available in domestic independent brand models in 2025.

There are fewer than 10 passenger car models equipped with steer-by-wire in the world, including Infiniti Q50, Q50L, QX50, Q60, Toyota bZ4X, Lexus RZ, and Tesla Cybertruck. The following table lists the models that have carried and are scheduled to carry steer-by-wire:

Seen from the plans of OEMs, steer-by-wire is expected to be available in domestic independent brand models in 2025.

3. Four-wheel independent steering will be the future development direction of steer-by-wire

The 4-wheel steering with steer-by-wire system (4WS-SBW) is composed of an independent mechanical transmission mechanism and a steering actuator motor. Each wheel can independently control the steering angle, enabling the vehicle to turn in place while increasing the freedom of driving attitude. The greatest significance of 4-wheel independent drive lies in safety. It can improve the stability and anti-skid control of the vehicle. It also provides power and steering dual redundancy for the autonomous driving system. Even if the steering wheel fails, steering can be achieved through the speed difference between the four wheels.

For example, the Hongqi integrated chassis structure comes from the 'Hongqi drive-steering integrated power chassis' technology of the intelligent driving safety chassis system of the e.RFlag electric platform (HME). This chassis technology platform pioneered a chassis domain control algorithm to achieve integrated control of steering, braking and suspension systems. It removes the motors that drives the wheel from the body, integrates them directly into the wheel, and installs them on the inside of the wheel hub instead. All four wheels adopt the same design. This is equivalent to directly canceling the transmission devices on traditional vehicles, allowing the wheels to drive 'themselves', and realizing seven motion modes including crab walk steering, fixed-point U-turn, front-wheel steering, and four-wheel steering.

BYD, Hongqi, Dongfeng and Schaeffler among others have laid out 4-wheel independent steering, a technology which is a major future development direction of steer-by-wire.

4. Steer-by-wire technology will disrupt cockpit design

Change 1: Steer-by-wire can enable foldable steering wheels to increase the available space in the cockpit. Nexteer's steer-by-wire can realize a foldable steering wheel, which automatically retracts during autonomous driving to increase the available space in the cockpit. ZF's steer-by-wire will allow the steering wheel to automatically retract in the future.

Change 2: Steer-by-wire technology can eliminate the steering wheel and replace it with other devices:

In November 2023, Schaeffler announced its force feedback operating joystick technology, which cancels the traditional steering wheel and replaces it with a joystick placed next to the armrest. Schaeffler's force feedback operating joystick has no mechanical connection with the front steering mechanism. This joystick can clearly feed the road sense back to the driver. The full steering stroke is about 100 degrees from the left to the right. The entire system development meets the relevant functional safety requirements and standards.

In May 2024, Hitachi Astemo's Smart SBWS used multiple control solutions to replace the traditional steering wheel, for example, using a mouse to control the steering wheel in the central armrest box, or using a new device on the left side of the front passenger to control the steering wheel. The system is expected to be mass-produced in 203X.