When a person encounters a new object, they usually look at it, touch it, and then use it. Doing this, they get a feel for the object's quality. The same thing happens when you first see a vehicle. A first look provides an impression of the quality and can heighten expectations. Then your fingers confirm whether the materials feel as good as you expected. Using the vehicle — operating the steering wheel, switches and other controls — allows you to form a more concrete evaluation of its quality.
Mazda's Kansei engineering program analyzes how people assess quality to ensure our products are as good as can be.
The appearance of the instrument panel, center panel, passenger-side dashboard, and door trim provides an indication of a vehicle's overall quality. Mazda employs a quantitative analysis method to assess the surface quality of interior parts in terms of glossiness, glare, contrast, and color. We achieve high quality levels by carefully selecting materials, surface treatments, and paints.
In order to achieve the desired glossiness, we carefully select low-reflective plastic resins and paints, and examine how surface treatments affect the reflection and diffusion of light. To prevent glare from localized reflection, we apply extremely fine surface grains, on a scale of microns. We consider the surface treatments of each shape to ensure the contrast between light and shadow is exactly as the designers intended. Colors appear different depending on the angle from which they are viewed and the angle of the light, so we fine tune the color of each part to ensure the overall appearance is coordinated.
There are certain parts that a driver often touches, such as the steering wheel, shifter, door trim, door armrests and parking brake lever. Ensuring these parts feel good is especially important.
For parts that are in extended contact with arms and hands, such as the door trim and arm rests, we use special equipment to measure how much weight is placed on them and how this affects the surface friction. We use the data to design parts that are soft and comfortable.
The steering wheel is the one part that a driver must constantly touch. We perform a quantitative analysis of how the shape, feel and grip of the steering wheel affect the senses. Our engineers wear a special glove, fitted with about 20 pressure sensors, as they perform a series of driving maneuvers. The glove precisely measures the pressure on the palm and fingertips during acceleration, braking and cornering. According to the data, the materials and the shape of the steering wheel are determined.
A key factor in designing a door mechanism is determining how much force must be applied to open and close the door. First, we use robotics to perform a "link analysis" and combine this with a computerized mannequin to examine the mechanical characteristics of human arms. From the results, we can determine the applicable force for opening and closing a door.
Then, using electromyography, we measure the muscle force needed for a Japanese female of average physique to open and close the doors. We assess the effects of altering the height, angle and size of the door handle. After that, the female tester uses finger pressure sensors to validate the shape of the handle and ease of use. Of course, the handle must also match the overall vehicle design.
Based on the test results for the Mazda RX-8 (right image), we applied a low-friction coating to help the doors open smoothly and positioned the handle to best suit the mechanical characteristics of the human arm.