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July 13, 2022
Test drive of the Lexus RZ with steer-by-wire (prototype)—Effortless steering control without needing to reposition your hands | LEXUS
LEXUS RZ
Test Drive: Lexus RZ Prototype with Steer-by-Wire
The Lexus RZ, its first dedicated battery electric vehicle (BEV), is slated to offer a model equipped with the latest steering system, steer-by-wire. Fumio Ogawa, a motoring journalist, reports on his test drive of a prototype of this model held at Lexus's test course.
Text by OGAWA Fumio | Photographs by LEXUS
With movements of about 150 degrees to each side, you can even navigate tight corners
The steering wheel is no longer round. Lexus has unveiled a steering wheel reminiscent of those found in aircraft and F1 cars. The BEV (battery electric vehicle) RZ, announced in April 2022, is expected to adopt a new technology called the steer-by-wire system.
The steer-by-wire system detects the driver's steering input via sensors and sends electrical signals to motors that control the front wheels. It eliminates the traditional physical connection, such as the steering wheel, steering shaft, pinion gear, and steering rack.
According to Takeshi Watanabe, Chief Engineer at Lexus International, who led the RZ's development, the steer-by-wire system pairs well with "DIRECT4," a system designed to achieve a satisfying driving experience through electronic control of the torque from the front and rear motors.
"Battery-powered EVs aren't boring; by effectively utilizing the motors, we can develop vehicles that drive exactly as the driver intends."
DIRECT4 and the steer-by-wire system significantly increase the freedom in defining the car's character. It can be tuned for luxury or for the quick responses of a sports car.
I test drove the Lexus RZ450e prototype equipped with the steer-by-wire system at the "Lexus Technical Center Shimoyama," a test course located in the Shimoyama region of Aichi Prefecture. Upon entering, I was surprised to find no circular steering wheel. As mentioned, it featured a yoke-style steering wheel, with the top and bottom sections cut off.
The grips are thick, and the cross-sectional shape varies depending on where you hold it. It's a very elaborate design. However, the intended grip points are at the 9 and 3 o'clock positions. If you hold it there, you can operate the car without shifting your hands. Instead of turning the steering wheel round and round, you use a sweeping motion with your arms, and with movements of about 150 degrees to each side, you can even navigate tight corners.