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Reinventing the wheel? Explanation of direction and yokes


Steering is one of the most important parts of driving, and feel and weight, as well as feedback via the tiller of what the front wheels are doing, play an important role in the driver’s impression. about the overall dynamics of their vehicle.

In the age of electric power steering (EPAS), the steering wheel also serves as a conduit through which driver assistance systems such as lane departure warning (LDW) and lane keeping assist (LDW) are available. LKA) and lane centering, works.

Many manufacturers send wheel vibrations to the LDW, and LKA often allows the car to control the steering wheel engine when it detects the vehicle is about to turn into another lane.

This means that any development in driving technology has the potential to dramatically change how a vehicle feels to the driver. Wired control systems, including their application in combination with aircraft-style steering wheels, are one of these technologies.

Basic operating principles and claimed benefits

Unlike previous electric and electro-hydraulic power steering systems, that is, there is no direct mechanical connection between the steering wheel and the front wheel to turn the vehicle.

Instead, the driver’s input is interpreted by a computer, which in turn sends instructions to the motors that can direct the rack and pinion steering to spin the front wheels by the required amount.

The Infiniti Q50 and Q60 were the first mass-produced cars to offer wire-operated standard on their models. Infiniti says it was developed with input from F1 driver Sebastian Vettel and branded the Direct Adaptive Steer System (DAS).

It uses a ‘steering force sensor’ that transfers input to a small electric motor linked directly to the wheel. Infiniti’s system features a backup electric motor, as well as a mechanical link that can be activated (automatically) via the clutch in the event of both primary and backup electric motor failure.

Infiniti says its system offers many benefits, including insulating the driver from unwanted shocks like potholes in the road. Infiniti claims the system provides more ‘feel’ when moving through the driving modes than the conventional steering system.

Other proponents of the steering system claim advantages in packaging and weight reduction, as the engine takes up less space than a mechanical linkage, which can be helpful in realizing the full range of benefits. packaging that electric vehicles bring.

The ability to calibrate advanced driver assistance systems much more precisely has also been raised as a benefit, which could be a necessary step on the road to autonomous driving.

Unfortunately for Infiniti, most buyers didn’t use the DAS in the Q50 and Q60, complaining that it felt unnatural and offered a ‘video game’ experience. This unfavorable public reception has resulted in Infiniti not using the system in future models.

(A survey about CarExpert the office found no fans of the Q50 and Q60’s steering among those who have experienced it – Ed.)

Suitability for yoke-style handlebars

It is becoming more and more common to install more compact, ‘staggered’ aircraft-style steering wheels.

These cut the top, bottom, or both parts from conventional steering wheels, reducing size and potentially increasing visibility of devices… at the expense of ease of taking actions manually like a three-point turn.

Tesla’s recently refreshed Model S and Model X were among the earliest cars to debut with a yoke-style steering wheel. CEO Elon Musk justified the decision by claiming the wheel improves the visibility of the front digital instrument cluster and ‘looks great’.

The main problem with Tesla’s approach is that the company stuck with a fixed 14.0:1 steering ratio, rather than any single-wire or variable/continuous steering to reduce the effort of turning at the wheel. low speed.

While the system may have worked on wider roads, some owners and reviewers have argued that the fixed steering ratio makes the car impractical to maneuver on three-point turns and sharp turns. Other operations require manual movement.

This may be in contrast to the yoke system developed by Toyota and Lexus, which is optionally available in some markets on new vehicles. bZ4X and Lexus RZ. Known as the ‘One Motion Grip’, the unit works in conjunction with a wire-drive system, similar in concept to Nissan’s DAS.

The wire steering allows Toyota to continuously and independently vary the weight and speed of the steering wheel, so the steering becomes noticeably faster during the last 10-20 degrees, enabling lock angle to lock is 150 degrees. In other words, you can keep your hands on the wheel at all times.

This means that in situations like making a U-turn or making a 3-point turn, the driver doesn’t need to change the steering wheel or use hand movements to steer the vehicle.

Toyota also claims other benefits of using the One Motion Grip steering wheel, including a more flexible interior design, more economical maneuverability and easier handling, as well as a more harmonious ride and Better steering response.





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