Automobile Seat Comfort Research Articles

Human-Centered Design and Manufacturing of a Pressure-Profile-Based Pad for Better Car Seat Comfort

A car seat’s function is to support, protect, and make passengers and drivers feel comfortable during a trip. A more uniform pressure distribution and a larger contact area usually provide less discomfort. Consequently, the seat pan’s material and geometry play an essential role in the design process. A shaped pad was opportunely designed and realized, starting from the pressure distributions between the buttocks and the seat pan; pressure data were acquired during an initial experiment involving 41 people, representing a wide range of percentiles. The shaped pad was compared with a standard one by building a special seat with an interchangeable internal pad and testing the standard and the new seat; the second experiment involved 52 people that tested both seats. The tests were conducted to assess comfort (33 subjects were asked to be seated for 1 min each) and discomfort (19 subjects were asked to be seated for 15 min each); during the tests, pressure distribution and contact area data were gathered. The results showed that, for both tests, about 80% of the participants, among which 100% of the female sample, preferred the shaped seat pan pad. Even if the material was exactly the same, the shaped pad seemed to be softer, more comfortable, and more suited to the body’s shape than the standard one. The design methodology was demonstrated to be very useful for granting a more uniform pressure distribution and a wider contact area, i.e., higher comfort and less discomfort.

A reshaped intelligent autonomous driving by using the influence and progress of human factor engineering concept

In modern society, with the improvement of people's taste of life and the change of people's consumption awareness and lifestyle, cars are no longer just a driving tool or means of transportation. People's requirements for cars are constantly improving, such as the comfort of car seats and the convenience of reversing radar. This paper examines the role of human factor engineering in the intelligent driving and gives some examples of the usage of the human factor engineering, and analyse it by Single-vehicle level analysis and Macro system level analysis. Then, the paper lists different human factor problems affecting intelligent driving. The paper discusses one iHCl system of human factor engineering which based on the Cognitive theory at three levels of perception. The paper analyses two cognizant. For the human users, it has the three-layer scene elements, data-driven, and goal-driven information processing mechanisms utilize dynamic mechanisms for information collection and subsequent response, allowing human users to perceive the updated information obtained in the dynamic environment. For intelligent system, For intelligent systems, it has a "top-down" decision-making processing mechanism. The feedback mechanism is composed of subjects such as goals, plans, and tasks.

Monitoring driver stress during highway driving using wearable bio-signal sensors

Various functions for improving automobile seat comfort have been developed to reduce driver stress. However, how drivers respond to the seat comfort functions in real driving has not yet been studied. This experiment evaluated the effect of a seat air-conditioning system (ACS) on driver stress by tracking changes in various bio-signals during 60-min highway driving. Heart rate, heart rate variability, skin conductance, and respiration rates were quantified using non-invasive sensors from 13 drivers while varying the seat ACS condition in hot weather. Study results show that the high-frequency power of the heart rate variability, mean skin conductance level, and mean respiration rate detected the changes in the seat ACS over 60%, implying the possibility of seat comfort monitoring using the bio-signals. Further research should be conducted with various environmental or driver conditions to improve detection performance.

폴리우레탄 폼 물성인자 기반 자동차 시트 컴포트 추정식 개발

Objective: The present study is intended to identify the material properties of PU foam through reviews of journal papers and technical documents and develop regression models to estimate seat comfort based on the material properties of PU foam.BRBackground: Automobile seat comfort is affected by the shape and size of the seat and its location in the driving workstation as well as the material properties of polyurethane foam (PU foam) and seat cover.BRMethod: A total of 16 material properties of PU foam were identified in the present study, the PU foam property data were extracted using the stress-strain curve data of 28 seats, and outliers were identified. Then, the regression models of seat comfort were constructed by applying the stepwise regression technique to the PU form and seat comfort data.BRResults: The adjusted coefficients of determination (adj. R2) of the seat comfort regression models were found 7.7% to 89.4%.BRConclusion: An Excel-based seat comfort estimation system consisting of the input of PU foam factors, the estimation of seat comfort, the addition of new stress-strain data, and the update of seat comfort regression models was developed to efficiently apply the developed seat comfort estimation models to the design of PU foam. BRApplication: The seat comfort estimation models developed in the present study would be of use to determine the material properties of PU foam for better seat comfort.

Preliminary study on perceived comfort of car seats: A quantitative approach to visual cues

The automotive industry is transitioning towards a more digital future - not just the digitalization of the product itself but also the process of customer interaction, such as during the product selection process. In the product selection process, companies are enabled to collect and analyze large amounts of customer and usage data but are also challenged to understand the gathered digital data. In designing physical components, analyzing, and understanding such data can provide a competitive advantage. In gaining deeper insight into the digital selection process of cars and for understanding customers preferences related to perceived comfort of car seats, we applied a visual appearance study by presenting digital information of physical components.

Research on seat perceived comfort evaluation based on factor analysis

Car seat is one of the most important parts of the direct contact with consumers, consumers' subjective perception of seat comfort depends on the choice of car, and the automobile industry in the perception of car seat comfort evaluation and research work, is still in its infancy, convened by the project through to the six major cities, 900 consumers respectively for 18 to subjective comfort evaluation of standard models, this article selects three same level models of standard models, for example, through the factor analysis method to calculate the subjective comfort ratings, and use the objective measurement data of subjective rating transverse comparison test. The results show that the subjective comfort score can reflect the comfort degree of the seat.

Evaluation of Car Seat Comfort Based on Relation between Seat Pressure Characteristics and Physiological Indices

Evaluation of Car Seat Comfort Based on Relation between Seat Pressure Characteristics and Physiological Indices

Testing the car seat's comfort

In this paper, four commonly used car seat covers, made from leather as well as from woven, knitted and 3D spacer fabrics are tested as sandwiched and separate layers to determine the effect of the lamination and layers on air and water vapor permeability. Different combinations of interlining materials are also tested to obtain the optimum comfortable car seat cover. This analysis gives us a real idea of which layer negatively affects the breathability of the car seat. The focus of this part of research was to identify the issues within the car seat material instead of factors like external cooling or the clothing of the driver. It was observed that the polyurethane (PU) foam and lamination significantly reduce the permeability of the car seats. The 3D spacer fabric shows the best top layer properties as compared to classical woven, leather or knitted car seat covers. The research shows how layers and lamination cause thermo-physiological discomfort of car seats.

A body-shaped lumbar-sacral support for improving car-seat comfort.

Nowadays, the ergonomic study of the driving position is a critical aspect of automotive design. Indeed, due to the rising needs on the market, one focus for car industries is to improve the perceived comfort related to the cars' interior. Driving a car for a prolonged time could cause complaints in some body-regions, especially in the lumbar-sacral area. Thus, special lumbar-sacral supports for driver seat has been proposed for reducing this kind of complaints. Development of two virtual and physical models of lumbar-sacral support for improving both the lumbar/sacral and overall perceived comfort while driving. Two prototypes of lumbar/sacral support have been realized: the first one was integrated into the seat, and the second one was shaped as a removable pillow (removable support). Fifty participants were asked to rate the perceived comfort in lab tests performed on a seating-buck by comparing three configurations (5 min each): a standard seat, seat with the removable support, seat with integrated support. Subjective data (by questionnaires) and objective data (interface pressure between backrest and driver) have been acquired and statistically processed. In addition, real driving tests have been performed to test the actual performance of the removable support in term of perceived comfort comparing it with the standard seat. Statistical correlations between subjective and objective data showed interesting results in comfort improvement through the adopted solutions. Real driving tests showed an improvement in comfort perception with the lumbar-sacral support towards the standard seat. Thanks to the virtual prototyping and the application of previous knowledge, coming from literature and experience, a solution for improving the overall comfort and reduce the lumbar/sacral pain while driving has been developed, tested, and assessed.

Testing the effect of textile materials on car seat comfort in real traffic

This study proposes a methodology that enables the comparison of textile materials from the point of view of corresponding comfort. Although this study focuses on textile materials used for the construction of car seats, the approach can be used more broadly. First, different aspects, which are more or less closely connected with our problem, are discussed. Among them, two characteristics, i.e. temperature conductivity and breathability, are important. Second, we discuss why it is important to have conclusions about comfort based not only on the subjective feelings of evaluators, but also on objective measurements. To that purpose, an experiment and a questionnaire summarising subjective feelings are proposed and concisely described. Furthermore, the choice of sensors, their placement in a car seat and the manner of recording data are discussed. Finally, the choice of appropriate statistical methods suitable for the analysis of collected data is discussed. The approach is illustrated via real experiments. Our findings support the current trend that the use of 3D spacer fabrics improves both breathability and sitting comfort in general.

Interval Scoring Method on Vehicle Seat Comfort Evaluation

This paper provided an evaluation method to analyze the comfort interval of automobile seats. According to the theory and analytical procedure of interval parameter structure, based on the human pressure data and valuation results of a large number of automobile seat comfort subjective evaluation tests, the uncertain mathematical relations between objective data of automobile seat comfort test and subjective evaluation scores could be established. This mathematical relation was called interval relationship. The author established the seat evaluation database with a large number of test results, and developed an evaluation method of seat comfort interval with the application of the mathematical model. The Result of the analysis on the feasibility and effectiveness of the evaluation method proved that it could provide more reliable seat comfort evaluation results. The seat design engineer could use this method to replace the complex manual seat evaluation process. Meanwhile, the comfort score provided theoretical guidance for automobile seat design and improvement.

Influence of automobile seat form and comfort rating on willingness-to-pay

Customers nowadays consider the driver's seat, specifically its comfort and aesthetic form, during the automobile purchase decision. As a result, much research has been recently conducted into seat comfort and the influence of the visual appearance of the seat on the perception of comfort. However, the cost of the seat remains an important contributor to overall vehicle cost, and the visual appearance of a seat may influence a customer's willingness to pay. We conducted an experiment measuring this tradeoff using hierarchical Bayesian conjoint analysis, a marketing method that elicits customer preferences and willingness-to-pay at the individual customer level. Utility models are statistically inferred for three brand segmentations using a dataset obtained through an online interactive web application. Results indicate that in a heterogeneous market, willingness-to-pay is affected by seat form and comfort rating, with particularly significant tradeoffs for the luxury automotive brand segment.

Numerical evaluation of time-dependent sagging for low density polyurethane foams to apply the long-term driving comfort on the seat cushion design

Car seat's bearing capacity, after a person takes a seat, is time dependent and tend to harden with increased time. Hardening of seat results from viscoelasticity of seat's foam pad, and has a great effect on a person's seating comfort in a long term driving mode. As such, evaluation of changes to bearing capacity is an important design factor that must be considered at the time of the seat design, and need to be evaluated quantitatively. This study intends to apply numerical analysis for quantitative evaluation of the changes to bearing capacity of seat cushions during a long term driving, and evaluate based on different materials of seat foam pads to be used as a reference material during the design. Car seat's comfort functions are divided into static comfort, evaluated in a time domain, and dynamic comfort, evaluated in a vibrating domain. However, as this study only intends to evaluate the seat cushion's hardening effects during a long term driving, we only evaluated the static comfort in a time domain. We assumed the long term driving to be two hours, quantified the hardening level to an amount of sagging, and evaluated three types of low density polyurethane foams with different material characteristics. We applied the analysis method used and verified in the previous research phase to numerically evaluate the amount of sagging depending on the seating time, and tested the foam pad's static compressive behavior and viscoelasticity behavior to acquire data on material's characteristic. In order to consider body's seating position, we used HPM-1 dummy model provided by ESI's PAM-COMFORT (finite-element analysis program exclusively for seat), and compared the amount of sagging. We were able to predict the amount of sagging of each material from the analysis results and confirmed noticeable differences.

Effect of Perforated Polyurethane Foam on Moisture Permeability for Car Seat Comfort

Effect of Perforated Polyurethane Foam on Moisture Permeability for Car Seat Comfort

Digital evaluation of sitting posture comfort in human-vehicle system under industry 4.0 framework

Most of the previous studies on the vibration ride comfort of the human-vehicle system were focused only on one or two aspects of the investigation. A hybrid approach which integrates all kinds of investigation methods in real environment and virtual environment is described. The real experimental environment includes the WBV(whole body vibration) test, questionnaires for human subjective sensation and motion capture. The virtual experimental environment includes the theoretical calculation on simplified 5-DOF human body vibration model, the vibration simulation and analysis within ADAMS/VibrationTM module, and the digital human biomechanics and occupational health analysis in Jack software. While the real experimental environment provides realistic and accurate test results, it also serves as core and validation for the virtual experimental environment. The virtual experimental environment takes full advantages of current available vibration simulation and digital human modelling software, and makes it possible to evaluate the sitting posture comfort in a human-vehicle system with various human anthropometric parameters. How this digital evaluation system for car seat comfort design is fitted in the Industry 4.0 framework is also proposed.

Evaluation of Sitting Comfort of Leather Car Seat

Evaluation of Sitting Comfort of Leather Car Seat

Articulation at shoulder level – A pilot experimental study on car seat comfort

This article reports on a pilot experimental study aimed at a first evaluation of the introduction of an articulation in the upper part of the seat backrest. The idea of introducing this articulation sprang from prevention of whiplash injuries and this study tentatively assesses its potential for improvement in comfort. This was done considering a pre-defined articulation height. A height for the articulation of 43.5 cm above the H-point of a reference seat was theoretically deduced based on a population with an average sitting height of 88 cm. Participants evaluated the articulated seat in comparison with the reference seat. Twelve participants were divided into three groups of sitting height. In a laboratory environment subjective comfort evaluations and preferred values of deployment of the articulation and of counter-tilting of the headrest were registered. Driving on the roads completed and validated the laboratory assessments. The reference seat was deemed less comfortable for the participants with short and medium sitting height than for the tall ones. There was a notable improvement in comfort for most of the medium and short sitting height participants when using the articulated seat. The articulation was fully deployed by most participants.

An on-the-road experiment into the thermal comfort of car seats

This paper presents an evaluation of thermal comfort in an extended road trial study. Automobile seats play an important role in improving the thermal comfort. In the assessment of thermal comfort in autos, in general subjective and objective measurements are used. Testing on the road is very difficult but real traffic conditions affect the comfort level directly, as well as the driver's experience to real conditions. Thus, for such cases real traffic situations should not be neglected in the evaluation of comfort. The aim of this study was to carry out, on an extended road trial study, an evaluation of thermal comfort using human subjects. In the experiments used, the 100% polyester seat cover had three different cover materials, which were velvet, jacquard and micro fiber. All experiments were carried out on a sunny day with ten participants over 1 h. They were carried out at air temperatures of 25 °C in a Fiat Marea 2004, which had an automatic climate function. Skin temperature at eight points and skin wettedness at two points on the human body were measured during the trials. Participants were required to complete a questionnaire of 15 questions, every 5 min. It can be concluded that there was negligible difference in participants’ reported thermal sensation between the three seats. According to objective measurement results, all seat cover materials have the same degree of thermal comfort. On the road the participants feel warmer around their waist than any other area of the body. It was suggested that the effects of real traffic conditions must be accounted for in comfort predictions.

Automobile seat comfort elements—Physiological demands, customer requests and realization possibilities

Automobile seat comfort elements—Physiological demands, customer requests and realization possibilities

Ergonomics modelling and evaluation of automobile seat comfort

Automobile seats are developed in an iterative manner because subjective feedback, which is usually of questionable quality, drives the design. The time and cost associated with iteration could be justified if the process was guaranteed to produce a comfortable seat. Unfortunately, this is not the case. Current practices are based on the premise that seat system design teams need objective, measurable laboratory standards, which can be linked to subjective perceptions of comfort. Only in this way can predictions be made regarding whether or not a particular design will be viewed by the consumer as comfortable. This type of forecasting ability would effectively improve the efficiency with which automobile seats are designed. In this context, the research reported, developed, and validated a stepwise, multiple linear regression model relating seat interface pressure characteristics, occupant anthropometry, occupant demographics, and perceptions of seat appearance to an overall, subjective comfort index derived from a survey with proven levels of reliability and validity. The model performance statistics were: adjusted r 2 = 0.668, standard error of estimate = 2.308, F (6, 38) = 15.728, p = 0.000, and cross-validated r (15) = 0.952, p = 0.000. From the model, human criteria for seat interface pressure measures were established. These findings could not have been attained without first demonstrating that (1) the data collection protocol for seat interface pressure measurement was repeatable and (2) seat interface pressure measurements can be used to distinguish between seats.