What is dynamic Kansei engineering? What is the purpose of tuning? Reconfirming its basics.

We look forward to working with you this year.Last year, as a self-introduction, I talked about the actual development that I myself worked on within an automobile manufacturer.So to speak, it is dynamic Kansei engineering as a "practical skill".What was the problem and how it was solved.It may have been a little difficult to see because the development of mass-produced cars involves complicated factors, but I think you can see the general situation.

From here, I will go into the main theory of dynamic Kansei engineering concretely, but before individual technical theory, I would like to reorganize the basic viewpoint of "What is dynamic Kansei engineering?" I think.
It seems difficult to say "dynamic Kansei engineering", but in ordinary words, it may be just "a device to enjoy driving a car".The point is to think about the performance of a car from the perspective of "enjoying driving."It is also a discipline at the development site that seeks ways to realize what to do from the standpoint of people who "want to enjoy more positively".So, in that sense, anyone trying to tune their car to their own style is already at the beginning of this research.

However, at the moment I said so far, you will notice that the evaluation criteria for "automobile performance" differ depending on various positions.For example, "fuel efficiency" is the highest priority for people who value the environment, resources, and household budget.For elderly people and VIPs, "ride quality" may be the first priority.For family cars, "economics and fashionability", for commercial cars, "reliability and durability", and of course, "safety first".It is easy to imagine that the performance to be emphasized will differ depending on each person's way of thinking.
That's fine, but in short, it is natural that it depends on the "position" or "values", that is, the "way of life" to put it exaggeratedly, but after acknowledging such a premise, it is still "fun to drive". It is our basic stance to try to think of ways to improve ourselves and to maintain such a position.
The car is also called a device for expanding physical functions, and when considered to be an extension of the body, it is a part that corresponds to bones, muscles, and nerves.Moving at will is of utmost importance, and unwilling movements can be life-threatening.Therefore, I think it is a natural desire to have fun moving one's body.
So what exactly is the problem?The theme of this seminar is to say that the target is "dynamic sensitivity". "Dynamic" is simply "movement". To put it plainly, "sensitivity" can be "sense".Therefore, "sense of movement" is also acceptable.The "sense of movement" when driving a car is "whether it is fun or not" for the driver.Based on that, we will re-evaluate from the concrete behavior of the car to the design at the component level.


Absolute performance and sensitivity performance

Our interest can be rephrased as "Kansei performance", that is, "Kansei performance".To put it the other way around, "performance unrelated to sensibility" doesn't matter, and to put it in the extreme, that's what it is.For example, "maximum speed" and "cornering limit" are basically calculated values ​​in design, that is, "absolute performance" as a car different from the difference in sensibility, and in itself. It is not "performance that appeals to sensibility".In other words, performance that is meaningful in terms of automobile engineering may not matter in terms of kansei engineering.

More importantly, sensibilities vary from person to person, either innately or acquiredly, and their performance cannot be evaluated on an absolute scale.Performance that appeals positively to one person's sensibility may have a negative effect on another.An extreme example is the movement of a roller coaster.It should be easy to imagine that the evaluation is divided into heaven and earth depending on who likes and dislikes.Therefore, when evaluating "Kansei performance", it is necessary to assume the position of the evaluator.
In light of the examples given above, it can be said that fuel efficiency and durability are close to "absolute performance".Whether or not it is important, I don't think that the judgment of good or bad will be reversed by people.So you can simply draw conclusions with numbers.But what about acceleration, for example?Acceleration performance that is excellent numerically may also be denied as giving a feeling of fear.The braking force is the same.
The same is true for steering sensitivity.It is even more subtle when it comes to exhaust noise.Some people prefer quietness in terms of absolute performance, others are particular about sound quality, and others expect changes in volume with acceleration.Evaluation of sensitivity performance is not possible unless the performance is specified for whom, such as the evaluation of riding comfort is divided according to the preference of hardness and softness.This is the reason why I said at the beginning that dynamic Kansei engineering is based on "the position of people who want to enjoy driving more actively".


Static and dynamic sensibilities

In order to discuss dynamic Kansei engineering in earnest, another prerequisite must be clarified. If we interpret "performance that appeals to sensibilities" in a broad sense, various sensibility performances are included in automobiles, such as design, tactile sensation, and the image created from them.And it goes without saying that "static sensibility performance" is an important value for the car and its owner in the sense of distinguishing between them.A car does not necessarily consist only of dynamic aspects, but it also exists as a space or skin that surrounds people.

Of course, such static sensibility performance is not an absolute performance because the value judgment differs from person to person.Therefore, in some cases, it can be said that it affects not only the relationship between the car and the driver, but also the relationship with a wider space, that is, a social space.A car as an existence can go beyond simply "performance that appeals to the driver's sensibility" to "performance that appeals to the sensibility of the surrounding community and the driver's personality."
"Cars speak for people" as much as or better than everything around us, such as homes, furniture, clothing and belongings.Therefore, dynamic Kansei engineering does not deny static Kansei engineering.
Although there are various choices as a matter of position, in the sense of loving automobiles, in the sense of going beyond the framework of mere automobile engineering, I think that they are rather comrades and can stand side by side.Otherwise, I think that "dynamic Kansei engineering" will be inevitable to be self-righteous.


Sensitivity target of mass production design and meaning of tuning

Then, what kind of position, values, and sensibilities are the cars mass-produced by automobile manufacturers designed for?Needless to say, considering the cost and profit, a car that can handle as wide a range of people as possible seems to be advantageous.

In "ergonomics" from before, we have made efforts to deal with more "humans" based on the distribution of height, sitting height, arm and leg length, etc.The same is true of what we now call "universal design," and the ideal is 100%.In that sense, the design around the driver's seat is particularly severe, and the coverage rate is evaluated by numbers such as "XX% of Japanese women" and "YY% of American men".It's the right way to do automotive engineering for mass-produced cars.Otherwise, some people will not be able to drive safely, let alone enjoy driving, so it cannot be said that they are aiming for "optimization to individuals", even if there are some compromises. I don't think there is.
However, in terms of Kansei engineering, things change completely.As mentioned earlier, human sensibilities are as diverse as physique.Therefore, assuming mass production, it is ideal to satisfy XNUMX% sensitivity.So, is it possible or not?

The decisive difference between physique and sensibility is that the actual situation cannot be quantified.There are various statistical data on the difference in physique, and in some cases it can be actually measured, so the coverage rate of the design value can be easily calculated.However, data such as the receptivity of human sensibilities to acceleration of launch probably does not exist and cannot be measured except for special ones such as those for space rockets.Therefore, it is basically impossible to design to satisfy everyone's sensibilities.
Therefore, the target value of dynamic sensitivity performance by automobile manufacturers is often set in relation to the market price.It is decided by the marketing concept (setting of selling points for the customer image of the market and the performance of competing vehicles, etc.) and the technical level that can be realized by the company.
Of course, since mass production is a prerequisite, there are also restrictions on price and cost.So, without a very challenging marketing strategy, mass-produced vehicle design would inevitably set the greatest common divisor, average and safe target.Although there are differences in performance depending on the vehicle type, grade, and options, on the other hand, there are also restrictions such as foolproof and reliability, so basically it is necessary to take a margin on the safety side.
If the width of the target can be narrowed like a sports car, the degree of freedom is not comparable to that of a general passenger car.In many cases, the developer himself can be one of the customers, so he can think of himself as a target.In other words, he can build sensibility performance that exceeds the customer's expectations, which he wants to ride, based on his sensibility.However, even though the range has narrowed, the principle of mass-produced vehicles survives within that range.That is an inevitable fate.
Sensitivity performance cannot cover 100% of drivers.Nevertheless, mass production design must be 100% oriented as much as possible, and it is the only one that solves this contradiction and realizes "optimization to individual" according to the principle that sensitivity depends on individual. The method, if it's tuning ... I think that's the position.


The idea of ​​"Kansei tuning"

Of course, with a car that has been registered as No., the basic design itself cannot be changed, and unlike the development team of the manufacturer, various trials and errors cannot be repeated.Therefore, tuning for absolute performance is impossible, dangerous, and even illegal in the first place.Given its use on public roads, it is inevitably limited to emotional tuning.The basics of tuning are to make some adjustments to fit your own sensibility on the premise of being ready-made.

But it's not very easy.In the first place, it is difficult to confirm one's own sensibility and driving skills, so whether or not "optimization for oneself" is really possible is a consequential theory.After paying a lot of tuition fees, I think many people have come to realize that "genuine is the best".In other words, it is often not possible to check in advance how the tuner's sensibility overlaps with one's own sensibility.
However, since the world is in the information age, at least it is possible to know in advance the sensibility performance that the tuner aimed for.And at the image level, you can predict the compatibility.I think it is more important to judge whether the tuner's way of thinking about tuning is closer to one's sensibility than the basic performance.

To reiterate, it is natural that sensibility depends on "position" or "values", that is, "lifestyle" to put it exaggeratedly.