Automobile Seat Comfort Research Articles

Automobile seat comfort prediction: statistical model vs. artificial neural network

The current automobile seat comfort development process, which is executed in a trial and error fashion, is expensive and outdated. The prevailing thought is that process improvements are contingent upon the implementation of empirical/prediction models. In this context, seat-interface pressure measures, anthropometric characteristics, demographic information, and perceptions of seat appearance were related to an overall comfort index (which was a single score derived from a previously published 10-item survey with demonstrated levels of reliability and validity) using two distinct modeling approaches—stepwise, linear regression and artificial neural network. The purpose of this paper was to compare and contrast the resulting models. While both models could be used to adequately predict subjective perceptions of comfort, the neural network was deemed superior because it produced higher r 2 values (0.832 vs. 0.713) and lower average error values (1.192 vs. 1.779).

Predicting automobile seat comfort using a neural network

This paper demonstrates the viability of employing a neural network for the purpose of predicting subjective perceptions of automobile seat comfort. The inputs included eight seat interface pressure measures, three anthropometric and demographic variables, and a subjective rating of the seat's aesthetic quality. The output was an overall comfort index derived from occupant responses to a survey with proven levels of reliability and validity. The neural network was developed and validated using data collected from 12 subjects, representing a broad range of anthropometry. The subjects evaluated five different front driver bucket seats in a repeated measures fashion. The neural network performance statistics were as follows: r 2=0.83, average error=1.19, and cross-validated- r(15)=0.85, p=0. The resulting knowledge (in terms of the relative importance of inputs) and design guidelines (i.e., human criteria for seat interface pressure measures) should reduce the cost and time associated with the current automobile seat comfort development process, which relies mainly on jury evaluations and is, therefore, executed in a trial-and-error fashion. Relevance to industry This study suggests that subjective perceptions of automobile seat comfort can be predicted using a neural network. The resulting design and product validation implications are pertinent to the current product development processes employed by the automotive seating industry.

Reliability and validity of a long term survey for automobile seat comfort

Automobile seat comfort is, undeniably, a subjective construct. In this context, jury evaluations, administered in the form of surveys, are, and will always be, the best way to understand customer/consumer perceptions and expectations of comfort. This is true even in the midst of a movement towards measurement technologies that produce objective data (e.g., pressure distribution, vibration transmissibility, etc.). Overlooked by this movement is the fact that design targets (i.e., human criteria for objective data) cannot be established without considering perceptions of comfort. Given the important role of surveys in the automobile seat comfort development process, it is surprising that well-documented aspects of survey design are given so little attention. The present contribution, while considering the wording of the survey items, the type and number of rating scale categories, the verbal tags associated with the categories, and the interest and motivation of the respondent, delivers a survey with acceptable levels of test-retest reliability, internal consistency, criterion-related validity, and construct validity. These are important attributes, if design decisions are to be made with minimal risk.

Automobile seat comfort: occupant preferences vs. anthropometric accommodation

Automobile seat design specifications cannot be established without considering the comfort expectations of the target population. This contention is supported by published literature, which suggests that ergonomics criteria, particularly those related to physiology, do not satisfy consumer comfort. The objective of this paper is to challenge ergonomics criteria related to anthropometry in the same way. In this context, 12 subjects, representing a broad range of body sizes, evaluated five different compact car seats during a short-term seating session. Portions of a reliable and valid survey were used for this purpose. The contour and geometry characteristics of the five seats were quantified and compared to the survey information. Discrepancies were discovered between published anthropometric accommodation criteria and subject-preferred lumbar height, seatback width, cushion length, and cushion width. Based on this finding, it was concluded that automobile seat comfort is a unique science. Ergonomics criteria, while serving as the basis for this science, cannot be applied blindly for they do not ensure comfortable automobile seats.

Evaluation of Methods, Approaches and Simulation Quality in the Experimental Evaluation of Car Seat Comfort and Functionality

This paper presents methodology, approaches and simulation actually used in the context of human factor studies designed to build knowledge on comfort and functionality of car seats. Backgrounds are literature and two own experimental studies. The methodology presented involves comparative studies with variation of one or several seat design factors. Scales for subjective evaluation of seat comfort and functionality, completing questionnaires and interviews are evaluated. Also compared are approaches to the design of sitting trials, involving real or simulated conditions. The simulations are qualified, in terms of what actually works. Physical data collection alternatives, namely, moving and still images and interface pressure data, are also commented upon. Anthropometric and other criteria for the selection of subjects are discussed together with sample size. Alternatives for tasks to be performed by trial persons are also discussed, along with the degree of freedom left to subjects. Alternative designs of standardized driving routes are compared. Driving tests validated the results arrived at in the laboratory tests, with both tests designed with methods and approaches presented in the paper.

自動車シートの座り心地評価 （第３報） 自動車運転座席の座り心地評価に及ぼすシート表皮層の影響

A sitting comfort of various car driver's seats, whose surface materials were different and structures and shapes were same, was evaluated tactually by consumers. The adjectives used for the sensory evaluation by human tactual sensation were examined by factor analysis. As the results, two adjectives “high-class” and “thick” were common and significant in evaluating the sitti ng comfort of car driver's seats by human tactual sensation. But, the adjective “sporty” was not evaluated. Further, the body contact area between the seat cushion and human buttocks was correlated with the adjective “thick” and that between the back-rest and human back was correlated with the adjectives “high-class” and “warm” evaluated by the tactual sensation . On the other hand, the body pressure between the back-rest and human back has a negative correlation with the adjective “soft”. And the contact area measured by the experimental system between the back-rest and the impact cylinder, when it gave the maximum force the back-rest, was correlated with “high-class” and “soft”.

自動車シートの「座り心地」に及ぼす表皮素材の影響について

自動車シートの「座り心地」に及ぼす表皮素材の影響について

Human Engineering, Subjective Evaluation, and Car Seat Comfort

Human-centered industrial engineering is one of the main topics of the last part of this century. Designers of new products must take into account the real needs of consumers. Because of this, new disciplines, based on human knowledge, are now emerging. The concept of subjective evaluatim is the most popular technique to extract and process semantics issued from a human being. New tools have also been developed to integrate these semantics into an industrial process. Fuzzy sets and the possibility distribution are some of these tools. This paper presents the application of fuzzy sets and the possibility theory in the context of car seat comfort evaluation.

Subjective evaluation of car seat comfort with fuzzy set techniques

Subjective evaluation is a central problem in the life cycle of most products. Automotive companies use subjective evaluation of car seat comfort to check the adequacy between specifications and effective realization. A great deal of time and money are spent to achieve this goal. To solve these problems, our project's goal is to save the expert knowledge and to automate this phase in order to achieve more flexibility. This article presents some of the first steps in saving the expert know-how in addition to help for decision making. We propose tools for the expert assessment acquisition and processing using a fuzzy set technique called expertons. Expertons are applied to a typical example related to our application. It emphasizes the suitability of expertons for the help for decision making. © 1997 John Wiley & Sons, Inc.

Subjective evaluation of car seat comfort with fuzzy set techniques

Subjective evaluation is a central problem in the life cycle of most products. Automotive companies use subjective evaluation of car seat comfort to check the adequacy between specifications and effective realization. A great deal of time and money are spent to achieve this goal. To solve these problems, our project's goal is to save the expert knowledge and to automate this phase in order to achieve more flexibility. This article presents some of the first steps in saving the expert know-how in addition to help for decision making. We propose tools for the expert assessment acquisition and processing using a fuzzy set technique called expertons. Expertons are applied to a typical example related to our application. It emphasizes the suitability of expertons for the help for decision making. © 1997 John Wiley & Sons, Inc.

自動車シートの座り心地評価 （第２報）自動車運転席の座り心地評価に及ぼす視覚の影響

A sitting comfort of car driver's seat was evaluated tactually or tactually as watching a road image by consumers.The adjectives used for the sensory evaluation by human tactual sensation or visual and tactual sensations were examined by factor analysis. As the results, two adjectives “high-class” and “sporty” were common and significant in evaluating the sitting comfort of car driver's seats by human tactual sensations or visual and tactual sensations, and the still time of sitting on the seat in evaluating by visual and tactual sensations was longer than that by only tactual sensation. Further, the body contact areas between the seat cushion and human buttocks and between the back-rest and human back were correlated with the adjective “sporty” evaluated by the tactual sensation or the visual and tactual sensations, but the body pressure and the contact area between the seat cushion and human buttocks and between the back-rest and human back were not correlated with the adjective “high-class” evaluated by the tactual sensation or the visual and tactual sensations.

Relation between Sitting Comfort Evaluation and Body Pressure Distribution on Car Driver's Seat.

Sitting comfort of car driver's seat was evaluated visually or tactually by consumers. The adjectives used for the sensory evaluation by human visual sense were compared with those by human tactual sense, and the relation between tactual sensory values and physical properties of car seats was examined by factor analysis. Two adjectives “high-class” and “sporty” were common and significant in evaluating the sitting comfort of car driver's seat by human visual sense or tactual sense, and tactual sensory values agreed with visual sensory values. Further, the body pressure and contact area between the seat cushion and human buttocks were correlated with the tactual adjective “high-class”, and those between the back-rest and human back were correlated with the tactual adjective “sporty”.

Back pain and car-seat comfort

A brief survey of the incidence of back trouble among the members of the Consumers' Association's car test unit led on to a survey of differences in the way those with and those without back trouble rated the comfort of car seats. The methods are described in some detail. It is suggested that people with back trouble may be a useful test tool for designers. It is concluded that car seats should cater for a wider range of a driver size, and should allow indivual drivers to adjust the amount of support given to different areas of the body.

The Use of Sheepskin Covers on Vehicle Seats

Driver preference for sheepskin car seat covers has been compared with their preference for other types of car seat overlays by the pair comparison method. The trials were carried out by professional drivers in several types of motor cars and trucks. Overlays were found to improve the comfort of motor car and truck seats. Woolled sheepskins were more comfortable in a popular motor car and in trucks than the other types of overlay tested. In an expensive car with more luxurious seating however they did not add to the comfort of the seat.