Following the Tesla Model S and Toyota bZ4X, the Lexus RZ became another model with a "supreme edge" steering wheel.
In the 1894 Paris-Rouen race, French engineer Alfred Vacheron replaced the steering control mechanism from the crank to the steering wheel in order to achieve more detailed control of the vehicle. Since then, the circle has become the mainstream shape of the steering wheel.
In the next hundred years, although we have also seen many brands try differently on the steering wheel, the various special-shaped steering wheels that have been screened in the end are still based on the circle.
But today, will the round steering wheel be replaced?
First of all, why is the steering wheel round?
In the early days of the invention of the automobile, the way to control the direction of the front of the car was a crank directly connected to the steering mechanism or a handlebar similar to a motorcycle. It can bring a very direct steering feel, but it is difficult to achieve precise control, and as the weight of the car increases, the too short force arm will also bring too heavy steering resistance.
This is also the reason why the aforementioned French engineers decided to use the disc as a steering control mechanism, the disc's larger force arm can make the steering easier, and the enlarged steering action also makes the control more precise. What's more, since the circle is the only geometry with rotational invariance, the driver can hold both hands in a familiar position at any steering angle.
With the introduction of the steering ratio, the steering wheel of most civilian vehicles at present often kills more than one turn to the side, which means that the driver needs to control the steering wheel by crossing his hands. At this point, the rotational invariance of the circle is even more important.
Since the invention of the automobile, driving has been the most core element of automotive products, and this is why the circular steering wheel has been preserved to this day. But as autonomous driving continues to evolve, the importance of driving is declining. And with that comes the evolution of the steering wheel form.
So why cut off half the steering wheel?
In fact, in the field of racing, the steering wheel has long been popularized. From the earliest Formula racing cars, to later prototype groups, to today's motorhome groups, designs that cut the upper edge of the circular steering wheel even along with the lower edge abound.
The advantages of such a design are also clear:
1. Due to the extremely low driving position of the car, the lack of upper spokes allows the racer to have a better forward view. For dashboards that are not integrated into the steering wheel, this design also leads to better information intuitiveness.
2. After removing some of the spokes, the weight of the steering wheel will drop significantly, but the steering arm will not be affected, so the design can slightly improve the steering sensitivity.
3. In the case of Formula and prototype racing, for example, legroom in the cockpit is limited. Therefore, when turning the steering wheel slightly, the steering wheel design without a lower edge will also leave a certain amount of leg movement space for the racer. In fact, many sports models use flat-bottom steering wheels for this purpose as well.
Of course, these three characteristics have nothing to do with automatic driving.
Many car companies said that when the era of automatic driving really arrives, there is no need to reserve a place for the steering wheel in the cabin. This is easy to understand, no need for human driving, naturally no need for steering wheels. But before fully autonomous driving, the steering wheel is in an awkward position. It needs to be experienced and adapted to the habits of use in a fully autonomous driving state by disappearing, and it needs to be in front of the driver if necessary.
Obviously, a stowable steering wheel is the best option.
At this point, another feature of the circle becomes a disadvantage - it has the largest perimeter-area ratio in the geometry, which determines that the circle is not a convenient shape for storage. The best way to deal with it is to leave the driver's most standard three- or nine-point grip position and cut off the other parts. After this treatment, the steering wheel is easier to stow inward along the steering column to form a "clean" cockpit.
The significance of car companies to introduce such steering wheels at the moment is also to allow drivers to adapt to the future steering wheel form more quickly.
But what kind of steering should the half-cut steering wheel be equipped with?
As the first mainstream model to have such a steering wheel, the new Tesla Model S received a lot of attention at the beginning of its release. But after the North American market began to be delivered, a series of criticisms of the steering wheel followed.
New things are not adapted and recognized by the public, which is the normal law of development. But in the case of the Model S, Tesla does have something wrong.
1. The steering ratio is too large. Killing 1.2 laps on one side is indeed normal for civilian cars, but when moving the car at low speed, this still requires a lot of cross-handed movements. And because the vast majority of drivers do not strictly hold the steering wheel three or nine points habit, so the yok steering wheel will bring great inconvenience to this action, many people will still subconsciously look for the missing upper edge of the spokes.
In racing cars that use the supreme steering wheel, the number of laps killed unilaterally is basically within 3/4 laps. And in addition to some special corners such as fairmont hotel bend at monte carlo and hairpin bend at guia circuit, racers rarely encounter situations that require cross-hand operation during competition.
2. Touch keys are too focused. The biggest impact of the yoke steering wheel on driving habits is to force the driver's hands to grasp the three-nine point position on the steering wheel at all times. However, when the steering wheel is turned sharply, the driver will mistakenly touch the buttons that are also located at three or nine o'clock in the middle of the busy. Obviously, this leads to user disgust.
This also explains why track racing uses an unconventional steering wheel with a large number of buttons, knobs and screens, while rally cars and drift cars that require a lot of steering action still use traditional discs.
Therefore, the better way to make the steering wheel of the supreme edge is to reduce the number of steering laps as much as possible while ensuring the steering angle, that is, to reduce the steering ratio. In order to make up for the instability of small steering ratios at high speeds, the variable steering ratio has become the best partner for this type of steering wheel.
That said, we need steer-by-wire.
Pros and cons of steer-by-wire
Steer-by-wire is to cancel the mechanical connection between the steering wheel and the front wheel, and use electrical signals to communicate between the steering wheel and the steering machine. Steer-by-wire is where the One Motion Grip steering system used by toyota bZ4X and Lexus RZ is superior to the Tesla yoke steering wheel.
1. The steering wheel is only ± 150°, which is equivalent to killing less than half a circle on one side, completely avoiding the situation of crossed hands.
2. The steering ratio can change significantly with the speed, which ensures low-speed flexibility and avoids the instability caused by "too much direction" when driving at high speeds.
3. Since there is no mechanical connection between the steering wheel and the front wheels, the unnecessary movement of the wheels caused by bumps will not be transmitted to the steering wheel, and the driving safety is improved by avoiding "steering wheel thugs".
Most importantly, if the steering wheel of the future is really going to be in a retractable form, steer-by-wire is the only way to do it.
In fact, in the automotive field, wire control technology has been very mature. Electronically controlled throttle, electronic gear and electronic handbrake are all manifestations of in-line technology. But when that change came to the turn, the push was unusually difficult.
Because the steering wheel is the only control part in the car that affects the driving feel.
As early as 2014, Infiniti equipped the Q50 model with DAS steer-by-wire. In order to avoid the failure of the electronic control, the system is equipped with three sets of ECUs to improve redundancy; in order to ensure the steering feel, the system uses a direct-drive feedback motor similar to a racing simulator; and for safety in the extreme state, the system still retains the traditional mechanical steering column, and only adds a clutch device to it.
And the result of such painstaking efforts is that consumers walk into Infiniti's 4S store and say to the sales: "I want to buy a Q50, the one without wire steering." ”
As a simulator player, the author knows that no matter how good the simulator base is, it cannot simulate the steering feel that is exactly the same as that of the real car. For Infiniti, which is known for its handling and performance, the simulated steering feel does not satisfy its fans.
But then again, the problem may not exist on Toyota's non-performance vehicles. Compared with the steering feel, the target consumer may be more concerned about the comfort, economy and practicality of the vehicle. With the continuous improvement of motor technology and algorithms, it may only be a matter of time before the feel of simulated steering reaches the level of the real car.
As for Tesla, Musk is always going to blow the bull in front, so the hardware must be ahead of the curve. As for when to let the steer-by-wire and variable steering ratio appear on its own model, it is expected to be the same as when Cyberruck is officially launched.
Write at the end
For traditional car enthusiasts, whether it is the supreme steering wheel or steer-by-wire steering, the development of these two types of trends will inevitably damage the driving pleasure. But just as manual transmission, pull-wire throttle, and hydraulic power steering continue to die, this is an irreversible development trend. No one refuses to fly a smarter, more electronically integrated Airbus plane because steel, hydraulically controlled Boeing aircraft are more interesting to fly.
Unless you are a pilot at Air China.
However, before there was no variable steering ratio and steer-by-wire steering, all the practice of cutting the steering wheel in half was a hooliganism.