New Energy's pure electric vehicles andsmart vehicles with Internet of Vehicle have become the two main developingdirections. Steer-by-Wire (SBW) technology of automobiles is a key technologyfor the development of pure electric vehicles and smart vehicles. It not onlyimproves the handling stability of automobiles, but also can be integrated andcontrolled with other control systems of vehicles to make the car moreintelligent.

1. It is an inevitable need to improvehandling stability of automobiles.

Ithas been shown that variable transmission ratio (refers to the transmissionratio of the steering system changes with the vehicle speed and steering wheelangle, rather than with the steering wheel angle only in the traditional sense)of the steering system can improve the automotive handling performance, butordinary Electric Power Steering is difficult to meet this requirement due tothe existence of mechanical connection. However, some variable ratio mechanismssuch as the dual planetary gear mechanism of the BMW AFS (Dynamic SteeringSystem) and the harmonic gear mechanism used in the 2008 Audi A4 havecomplicated structures, high manufacturing costs, large occupied space, andaffect ‘road feeling’ when active control is performed which often results inless ‘road feeling’ information obtained by the driver, but a moderate roadfeeling is especially important for high speed vehicles.

2. It can effectively reduce the driver’scasualty rate.

Inthe accident of a collision, the steering wheel is an important factor incausing the driver to suffer casualties, and the rearward movement of thesteering wheel is also often due to the existence of mechanical connection.However, because of the elimination of the mechanical connection between thesteering wheel and the directive wheel, the SBW system of the automotivecompletely escapes from the inherent limitations of the conventional steeringsystem, and improves the driver's safety while improving the convenience andsafety of the car steering.

3. It is good for the design andmanufacture of automobiles.

Sincethe SBW system eliminates the mechanical connection between the steering wheeland the directive wheel, it can free up space to install other components, andcan flexibly change the steering wheel to right or left according to theregulatory requirements of different countries.

4. Meet the requirements of automotiveelectronic and integrated control systems

In the1960s, Kasselmann in Germany tried to develop an electronic steering system toreplace the mechanical steering system. Due to the limitation of electronictechnology and control technology at that time, it was unsuccessful. In 1988,Japanese Suzuki Motor Company developed EPS technology. Although it has manyadvantages over the traditional hydraulic power steering(HPS), there are stillinherent deficiencies in conventional steering devices. The continuousdevelopment of electronic technology and the practical experience of electricpower steering have led to the development of pure electronic SBW systems.