Search Results

In modern society the automobile is an essential companion in everyday life. Be it commuting to and from work or during our leisure time – every week most of us spend many hours sitting in their car. In this context the seat is the main interface between the human being and the automobile itself. Functioning well, this close relationship can foster the well-being of the passenger and raise his spirit; being flawed, it can cause severe pain in the back after a long journey. Thus, for car manufacturers, the aspects of seat comfort are becoming more and more prominent in distinguishing themselves from their competitors. Despite its importance, the development of comfort parameters in automotive seating still is consigned to the subjective judgements of a small number of seating experts or randomly selected test subjects.

In modern society the automobile is an essential companion in everyday life. Be it commuting to and from work or during our leisure time - every week most of us spend many hours sitting in their car. In this context the seat is the main interface between the human being and the automobile itself. Functioning well, this close relationship can foster the well-being of the passenger and raise his spirit; being flawed it can otherwise cause severe pain in the back after a longer journey. Thus, for car manufacturers, the aspects of seat comfort are becoming more and more prominent in distinguishing themselves from their competitors. Despite its importance the development of comfort parameters in automotive seating is still being consigned to the subjective judgements of a poor number of seating experts or randomly selected test subjects.

For car manufacturers, seating comfort is becoming more and more important in distinguishing themselves from their competitors. There is a simultaneous demand for shorter development times and more comfortable seats. Comfort in automobile seats is a multi-dimensional and complex problem. Many current sophisticated measuring tools were consulted, but it is unclear on which factors one should concentrate attention when measuring comfort. The goal of this paper is to find a model in order to predict the overall seating discomfort based on body area ratings. Besides micro climate, the pressure distribution appears to be the most objective measure comprising with the clearest association with the subjective ratings. Therefore an analysis with three different test series was designed, allowing the variation of pressure on the seat surface. In parallel the subjects were asked to judge the local and the overall sensation.

Ergonomic product design can be divided into the parts of physical ergonomics (anthropometrics) and cognitive ergonomics. I regard to the visual cognition, the anthropometric and cognitive ergonomics are very closely connected. The visual cognition process is based on physical as well as psychological components. The information processing in the brain needs the visual perception with the eyes. This visual perception needs some optical attributes for good viewing conditions of the eye. The international widely-used 3D-Man-Model System RAMSIS receives some additional functionality for analysis and practical design of to simulate these viewing conditions in the car. These new RAMSIS functions include methods for the analysis of reflective glare, visual acuity, reading precision, visual fields, limited accomodation, glasses, progressive addition lenses and electronic displays.

The perception of visual information is the major input requirement for the psychological cognition process. The quality of perception of visual information is impaired by the geometrical and optical conditions of the displayed information. This concerns all technical information of the car as instruments, optical indicators, telltales and control displays. The international widely-used 3D-Man-Model System RAMSIS receives some additional functionality for analysis and practical design to simulate these viewing conditions in the car. These new RAMSIS functions include methods for the analysis of sight shadows, limits of visibility of liquid crystal displays, the time of focus shifts of the driver and the modelling of the optical parameters of head-up displays. These capabilities will enable a RAMSIS user to allow for (degraded) visual performance when designing the rising number of user interface displays in cars and airplanes.

This paper presents the usage of the Digital Human Models (DHM) PCMAN and RAMSIS to determine parameters for a supported ingress and egress on a mock-up. Sports cars with lower seating positions show occurring difficulties among older drivers during ingress/egress. To equip sports cars with higher seats or narrow door sills seems limited due to design aspects. Therefore the idea of an ingress/egress support system arose. To build a mock-up, it needs specific dimensions already in the CAD design phase. Here DHM-systems are utilized. As no similar systems are known, no ballpark figures for trajectories of the seat or movement ranges can be derived from literature. Therefore pre-tests were done with a simple manually moved seat. Test persons showed high acceptance and discomfort reduction. In order to design a proper testing environment for repeatable and reliable results, a variable seat with electric motors is built into a mock-up with a package of a sports car.

This paper concerns a former experimental study of the Lehrstuhl für Ergonomie of TU München, where in the first step correlations between pressure and discomfort were found for the seat pan. In the second step these findings were validated for long term discomfort. Now an additional correlation for the back should be found, which is essential for later research. In this context tests conducted before should now be confirmed and validated by another seat comfort model with a higher number of subjects and a long term test, too. Interesting part of this study will be the intercorrelation between seat pan and back.

Often, pressure distributions on seats are referred to as an objective method to quantify seat comfort. However, the reliability of seat pressure measurement is yet unknown. Therefore, it is important to know how reliable these pressure measurements are, before using them effectively as a means to predict seat comfort based on pressure measurements. Experiments were conducted to determine the inter-individual and intra-individual variation in pressure distribution. The obtained variation ranges of the mean pressure in defined body areas are presented.

In this paper a project is described on finding a relationship between discomfort and contact force distribution between human and seat. In the first step experiments were conducted to find correlations between pressure and discomfort. In the second step these findings were validated for long term discomfort. The gained knowledge provides the possibility to check the long term riding properties of a car seat by taking the pressure distribution which takes only a few minutes. Furthermore, pressure distributions which are computed by digital human models can be evaluated with this knowledge.

The development times of car seats decrease while the demand for more comfortable seats increases at the same time. To fulfill this trade-off, numerical simulation of the body/seat interaction could be used. Therefore numerical models of the sitting human are needed. For this reason a 3D-FE-model of the thigh and pelvis of a 50th percentile male has been developed. The surfaces of the thigh and of the bones were gathered by a laser scanner. For the undeformed outer shape a test subject was chosen who has the anthropometry of a 50th percentile male. The geometry of the bones was scanned from a skeleton of a 50th percentile male. From the scanned data 3D CAD surfaces were derived. Within the CAD-system the bony structures were positioned inside the outer shape of the thigh and pelvis using computer tomography images. The biomechanic properties of the soft tissue were determined through indentation tests on test subjects.