Rear Steering

Rear wheels turn up to 5 degrees

Video of 4WS in action

Diagram: Rear steering overview

Diagram: Rear steering schematic

Diagram: Rear steering, connecting parts (page 1)

Part Listing: Rear steering, connecting parts (page 1)

Diagram: Rear steering, connecting parts (page 2)

Part Listing: Rear steering, connecting parts (page 2)

Diagram: Rear steering, gear

Part Listing: Rear steering gear (4ws)

The World's First Active 4WS

Sharp steering response and excellent stability have been realized with the world's first rear-wheel automatic steering system as seen in this video. It includes a yaw-rate sensor*, featuring speed and steering-angle sensors, which instantly detects sudden car deflections. Thus, the car hardly drifts at all when driving at high speeds, during lane changes, or in strong crosswinds, drastically reducing the burden of driving and making it safer and more pleasant. An anti-phase rear-wheel steering mechanism coordinated with the steering angle has also been adopted for this 4WS system, assuring quick direction changes at low speeds.

Note: The yaw-rate sensor detects the angular rotation speed of a car about its horizontal center of gravity. The sensor thus makes it possible to detect changes in the car's direction due to steering, as well as changes caused by external disturbances such as crosswinds or snow.”

Source:

• Toyota press release
• https://forums.somethingawful.com/showthread.php?threadid=4000641&userid=0&perpage=40&pagenumber=3, accessed 2023-05-11
• https://d9dks0ahhbx8k.cloudfront.net/5a7a364c199de.mp4, accessed 2023-05-17