Automotive industry analysts in Europe and North America predict that higher adoption of electric power steering (EPS), steer-by-wire (SbW) and rear-axle steering / all-wheel-steering (AWS) will be some of the biggest drivers in the fast-evolving automotive steering systems vertical.
Systems that utilise the rear wheels as well (in addition to the front wheels), for steering, can help reduce the turning circle at low speeds, thereby making the vehicle more easily manoeuvrable, and at the same time, they can also help increase vehicle stability at high speeds. Of course, the degree of movement available for the rear wheels is much smaller than that for the front wheels, which continue to handle most of the steering function.
At low speeds, 4WS/AWS systems make the rear wheels turn (only by a few degrees) in the direction that’s opposite to the direction in which the front wheels are turning, as this helps with low-speed manoeuvres, while at higher speeds, the rear wheels turn in the same direction as the front wheels, which promotes stability.
While OEMs did experiment with 4WS/AWS systems in the 1980s and 1990s, these systems fell out of favour after that due to their higher cost and complexity. Now, however, due to the dynamic advantages that they offer, such systems are once again being developed by leading tier-1 technology suppliers (not just for cars but also for commercial vehicles) and one can find 4WS on some high-end cars produced by Ferrari, Porsche, BMW and a few others.
In each application case, electronic sensors that monitor various parameters (steering wheel movement initiated by the driver, vehicle speed, gear position, suspension movement, pitch and yaw data etc.) decide the degree to which the rear wheels move, in accordance with the front wheels, for best possible handling. Consequently, all-wheel-steering systems have the potential to boost safety, since they increase the effectiveness of anti-lock braking and traction control systems. At higher speeds, especially, AWS systems provide inherently higher levels of traction to begin with, which positively affects a vehicle’s handling characteristics. Furthermore, in the case of emergency braking or steering, with increased and/or sudden driver inputs, the position of the wheels can help ABS and TC systems do their job better. Going forward, recognising the potential improvements in handling and safety that AWS systems can bring to their cars, more OEMs are expected to use such systems, especially on high-end vehicles
Коротше, зараз - це зовсім інша річ, ніж 20-30 років тому.
Я їздив на BMW з інтеграваним активним рулінням.
