Handbook of Automotive Human Factors

Motoyuki Akamatsu

• Publisher: CRC Press
• Year: 2019
• ISBN:
  9780429536656
• Edition: 1
• Topic: Computer Science
• Subtopic: Human-Computer Interaction
• Index: Computer Science

Thanks to advances in computer technology in the last twenty years, navigation system, cabin environment control, ACC, advanced driver assistance system (ADAS) and automated driving have become a part of the automobile experience. Improvement in technology enables us to design these with greater flexibility and provide greater value to the driver (human centered design). To achieve this, research is required by laboratories, automobile and auto parts manufacturers. Although there has been a lot of effort in human factors research and development, starting from basic research to product development, the knowledge and experience has not been integrated optimally. The aim of this book is to collect and review the information for researchers, designers and developers to learn and apply them for further research and development of human centered design of future automotive technologies. Automotive human factors include psychological, physiological, mathematical, engineering and even sociological aspects. This book offers valuable insights to applying the right approach in the right place.

1

Overview of Automotive Ergonomics and Human Factors

1.1 Ergonomics and Human Factors for Making Products and Systems Compatible with Humans

Ergonomics and human factors is a study for designing products, systems and environment that are compatible with human characteristics. It is an interdisciplinary field integrating psychology, physiology, engineering and design. Ergonomics originated with concern for occupational health in the latter part of the 19th century (Jastrzebowski, 1857). ‘Human factors’ entailed focus on human abilities while using a certain system, mainly in the United States and the United Kingdom around the time of World War II. It was recognized that in order to improve the performance of an overall system, it was necessary to take into consideration the human characteristics which are part of the factors constituting the system. It is generally considered that ergonomics/human factors developed in mid 20th century, though the ergonomic design of automobiles was born at the end of the 19th century (Akamatsu et al., 2013).

As automobiles came into wide use after World War I, the issue of automobile accidents drew widespread attention. At the end of the 1920s, a German psychologist, Narziss Ach, proposed an ergonomic concept called psychotechnik (i.e., psychological engineering), emphasizing the need for technology based on psychological studies (Ach, 1929). Meanwhile, at the end of the 1930s, T.W. Forbes in the United States pointed out that accidents are caused not by specific people, but by normal people, and asserted that safety is related to the limits of human abilities, such as visual ability and response time, and therefore human factors, such as psychological and physiological characteristics, should be taken into consideration when designing automobiles (Forbes, 1939). Around this time, it was decided that human characteristics should be understood scientifically so that automobiles are designed according to them.

1.2 Beginning of Human-compatible Automobile Design

At the end of the 19th century, the gasoline-fuelled internal combustion engine was invented, leading to the manufacture of automobiles as machines that move the vehicle body by using power. They were machines fully controlled by humans, whether moving forward, stopping, or turning right or left. Improvements were made to enable humans to operate them; gradually they developed into the current form of automobiles.

The signature improvements were the circular steering wheel and foot pedals. In the early days, a bar handle called a ‘tiller’ was used as the steering mechanism in order to make the structure simple (Fig. 1.1, left), but it was found that the handle would shake wildly when driving fast on an unpaved bumpy road and the driver would face trouble in controlling it. Therefore, a bar handle with grips on both sides was developed to allow the driver to hold the grips with both hands before the round steering wheel using a gear was introduced.

In a horse-drawn carriage, the speed was decreased by making the horse to slow down its walk. So, it was sufficient to have a parking brake by which the driver pressed the shoe to a carriage wheel or axle with the help of a hand lever. However, since the force applied by a hand lever was insufficient to stop a fast automobile (Fig. 1.1, right), it was replaced with a foot pedal that could apply a greater force. The foot pedal was initially positioned on the vehicle floor close to the seat, but it gradually came to be positioned towards the front. In an ergonomics textbook, you will notice that the maximum force is applied by a foot when it is applied towards the front direction. Pioneering automobile developers empirically discovered the ergonomic pedal position for hard braking.

The 1930s saw the emergence of many designs and functions aimed at safety or driving ease. For visibility, originally hand-operated wipers were replaced by air-driven or electric wipers, and such new equipment as a defroster (Fig. 1.2) and a mirror that could avoid glare at night time driving were developed. Also, in the 1930s, the direction-indicator switch was positioned at an easily reachable part of the instrument panel or on a lever protruding from the steering column to make it easier for the driver to operate the switch (Fig. 1.3).

The steering with the help of a round handle and the acceleration/deceleration control by a foot pedal did not change for 100 years. Of course, keeping the manner of operation consistent was a basic ergonomic design principle, so no need was felt for making unnecessary changes. Furthermore, no tool better than a round handle that can be operated with both hands was discovered for making both slight correctional steering operation for maintaining straight running and large turns at intersections, and for doing these smoothly. The manner of operation that has changed is the introduction of the shift lever. The drive-by-wire technology increased the degree of freedom of design. Whereas the gearshift on the centre control still remains due to maintenance of consistency in the manner of operation, the paddle shift was positioned close to the steering for the same reason as the direction indicator.

Although the introduction of drive-by-wire technology has increased the degree of freedom, no dramatic change is expected in the future unless there is a notable change in the concept of operation, such as changing the tyre direction or changing the pressing force of the brake pad. If the concept of operation were to change, it would be by progress in automated driving technology (see 5.4.2.6). If automobiles gain intelligence, they may become machines that would be controlled by commands or communications, rather than manipulations. Then there would be a need for conducting additional research and development.

1.3 Vehicle Cabin Design

Until around 1920, the positional relationship between the steering wheel/pedal and the seat had been fixed after being designed. Automobiles were not only driven by men, but were also driven by active women. Such women must have had trouble with the layout designed for men. Around the 1930s, the seat-sliding mechanism was introduced (Fig. 1.4).

A group led by R.A. McFarland in the United States collected data on body sizes and published the data in a series as documents of the Society of Automotive Engineers (SAE) from around 1950 (McFarland et al., 1955). He presented the percentile of measurement, which is an important concept in ergonomic design. Understanding that vehicle interior design based on average body measurement values would only satisfy a limited number of people whose body measurements are close to the average values, he indicated the 5th percentile as the minimum value and the 95th percentile as the maximum value (Fig. 1.5).

After around 1930s, when rounded aerodynamic body shape was introduced, it was considered that automobile collision accidents resulted from oversight and that it was important to secure visibility in order to prevent accidents. Therefore, researchers worked on improving both direct and indirect visibility through mirrors. A method to evaluate the range of the driver’s visibility was developed based on the range of areas illuminated by lamps positioned at locations that correspond to the driver’s eyes (Hunt, 1937). The problem of visibility does not only involve the problem of the size and position of the windows and pillars, but is strongly related to the size of the human body. Since visibility depends on the positions of the eyes, the seat position that decides the eye position and the driver’s body size become an issue.

A concept that was introduced for considering the eye position is eyellipse. When considering the variations in human body size, variations in the seating location on the seat, and differences in the seat position, the distribution of eye locations can be approximated to a three-dimensional ellipse. Therefore, an ellipse based on the percentile values of the three-dimensional distribution of eye locations was named ‘eyellipse’. These were published by the SAE as SAE standards by the end of the 1950s and served as the basis for the cabin design (SAE Recommended Practice J941, 1965).

In the design process, such human body size is difficult to deal with if there are only numerical data. So, in the 1960s, 2-D manikins and 3-D manikins were developed and standardized as SAE J826 (SAE Recommended practice J826, 1962). In the 1970s, computer technology made progress and the development of CAD manikins, which are manikins on computer, started. Chrysler developed CYBERMAN followed by SAMMIE which was developed in the United Kingdom, RAMSIS in Germany, and Jack in the United States. CAD manikins came to be used in the actual design process by being incorporated in CAD applications for designing automobiles, such as CATIA.

While 2-D and 3-D manikins are measurement models, CAD manikins can reproduce a body of three-dimensional shape, which require not only data of the human body size, but also data of the three-dimensional shape. Therefore, the manikins need technology for three-dimensional shape measurement and for modeling based on the obtained data. Because it is possible to move the manikin on the computer screen, dynamic human movements, such as getting in or out of the vehicle, can be evaluated. However, with regard to reproduction of human body movement, the main approach currently used is to reproduce the data measured through motion capture, and no modeling technology has been established yet for reproducing any intended motion. When evaluating the ease of getting in or out of the vehicle, not only the interference (contact) between the human body and the vehicle, but also the motion stress must be evaluated, and studies are under way to evaluate these by using CAD manikins.

Due to an increase in the number of elderly drivers, consideration should also be given, not only to the differences in the body sizes of the driver and passengers, but also to the influence of their age. Research and development are conducted for CAD manikins that take into account the change in posture, loss of muscle strength, and decrease in the range of joint motion in line with aging. A person’s motion is not decided by physical and spatial restrictions alone; it also depends on how the person perceives that space. Therefore, there is a need for CAD manikins in vehicle interior design, taking into account elderly people’s perceptual/cognitive characteristics.

1.4 Instruments and Displays

1.4.1 Instrument Arrangement

With regard to the visibility of instruments, there were few instruments until around the 1900s and up to around early 1910 when they were attached to the bulkhead separating the engine and the cabin, providing poor visibility (Fig. 1.6, left). In the late 1910s, an instrument panel began to be installed and an array of meters was arranged on a luxury car (Fig. 1.6, right). In the 1930s, a meter cluster was installed near the steering wheel, in order to improve the visibility for the driver. Incidentally, in terms of visibility, the first instrument that was positioned at an easily visible location was the thermometer attached to the radiator head and which emerged in the 1910s. This was later replaced by the radiator mascot.

Instruments came to be positioned in front of the steering wheel, where it is easy for the driver to see, but sufficient consideration had not been made with regard to their interference with the steering wheel. The use of eyellipse made it possible to design instruments at positions where their visibility was not obstructed by the steering wheel. From the 1950s, the meter cluster was moved up to the position on the upper part of the instrument panel. While the fascia was lowered to secure the view, the visibility of the meters was ensured. In the 1970s, non-reflecting glass came to be used for the surface of meters, thus reducing the glare and improving their visibility. In the latter 1990s, the center meter, which is positioned in the middle of the dashboard, appeared (Fig. 1.7). It was a position where the amount of the gaze shifted from the road scene ahead to the meters is small. The visual recognition time was experimentally measured, and the position was found to be notably effective, particularly for elderly people (Atsumi et al., 1999).

As new instrument technology, the head-up display (HUD) was introduced. HUD was originally developed for aircraft. Because it had a great advantage in reducing the amount of gaze shift, studies began in the 1970s to apply HUD to automobiles (Rutley, 1975). HUD was first mounted on mass-produced cars in 1988 on a GM car and a Nissan car (Okabayashi et al., 1989). Although HUD was proved to be ergonomically effective (Ward and Parkes, 1994), it di...

Table of contents

• Cover
• Title Page
• Copyright Page
• Foreword
• Preface
• Table of Contents
• 1. Overview of Automotive Ergonomics and Human Factors
• 2. Ergonomic and Human Factors in Automobile Design and Development Process
• 3. Comfort and Quality
• 4. Driver State
• 5. Driver and System Interaction
• 6. Driver Behavior
• Index