X-by-Wire Chassis The New Billion-Dollar Market

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SIMTOS (Seoul International Machine Tool Show)

Peugeot has announced the series use of steer-by-wire. Many other manufacturers also rely on x-by-wire systems—suppliers expect sales in the billions.

With the "Polygon Concept", Peugeot shows what the future of its compact cars could look like. The technology used in the study is much closer to series production than many of the design elements. For example, the rectangular "Hypersquare" steering wheel in combination with steer-by-wire technology. Both could go into series production in 2027 in the successor to the 208. There is no longer a direct mechanical connection between the steering and wheels; all commands are transmitted electronically. Chinese car manufacturer Nio has already launched a model with this technology on the market. Many other OEMs will soon follow suit. For suppliers such as Bosch, ZF and Schaeffler, this opens up a growth market that promises billions in sales in the coming years.

Over the summer, a large number of suppliers presented their respective steer-by-wire and brake-by-wire portfolios. The basic principle of the technology, also known collectively as "x-by-wire", is the replacement of mechanical and hydraulic components with electromechanically driven actuators. The pressure on the pedal is no longer transmitted to the brake shoes via a hydraulic system. In the steering system, for example, the steering rod is no longer used as the connection between the steering wheel and steering gear.

Variable Steering Angle

With mechanical steering, the ratio is defined once and can then no longer be changed. With the steer-by-wire concept, the steering angle can be varied depending on the application. This means that you don't have to keep your hands on the steering wheel when driving through hairpin bends, for example. The same applies to everyday maneuvers such as parking or turning. Peugeot can therefore use a rectangular steering wheel.

Steer-By-Wire

Test Drive With Peugeot's Square Steering Wheel

In the Polygon concept, the French manufacturer has limited the steering angle to a maximum of 170° in each direction. This corresponds to just under one full turn in contrast to three full turns with a conventional steering wheel. At higher speeds, Peugeot writes, a minimal movement of the Hypersquare is sufficient to adjust the direction of travel.

Decoupled Steering Wheel

At its test site in Boxberg in late summer, Bosch discussed another function that car manufacturers can implement with steer-by-wire: a steering wheel that is decoupled from the driving action. When the traffic jam pilot takes control or the car parks and unparks itself, the steering wheel could remain stationary during the maneuvers. As a result, the controls on the spokes remain easily accessible and there is a defined takeover position.

In advanced assistance systems, central and domain computers are increasingly taking over vehicle control. Functions for the chassis, i.e. brakes, steering and damping, are bundled there. If car manufacturers rely on electromechanical systems here, the individual areas can be better coordinated with each other. One example is the domain control unit that BMW has developed for the "Neue Klasse" platform

Drive And Driving Dynamics on One Control Unit

The new control unit combines drive and driving dynamics functions at BMW. The computer controls acceleration and braking, vehicle stabilization, dynamic steering functions and load management. The manufacturer highlighted the computing speed as an advantage when presenting the technology. Centrally processed, the information for drive, braking, charging, recuperation and partial steering functions can be evaluated ten times faster than with previous systems.

The potential of by-wire technology for more comfort, greater efficiency and new functions is enormous. The technology will also become established in volume models in the coming years. The high turnover for suppliers also results from the safety requirements for braking and steering systems. As described above, some components are no longer required. However, the power supply, actuators and sensors, among other things, must be redundant. In other words, they are installed twice or otherwise protected in the event of a malfunction.