Design and analysis of experiments aimed at improving the aircraft seat comfort for young and elderly passengers

Population ageing is becoming a global phenomenon. According to the United Nations report World Population Ageing, "the number of older people aged 60 or over was about 202 million in 1950, accelerated to 841 million in 2013, and will triple by 2050". The contextual implementation of active and healthy ageing policies, modifying the expectation, quality and lifestyle of the elderly, is offering opportunities and challenges on various aspects of daily life and health management: among the various positive aspects, this has determined an increase in mobility for recreational purposes and therefore an increasing complexity of the needs connected to it. These changing needs must be considered in the design of transport environments to ensure dignity and autonomy for passengers, in accordance with the policy of non-discrimination promoted by European regulations for users with reduced mobility (EC n.1107/2006). In 2017, following a positive trend begun in 2010, passengers who used air transport for their journeys to or from European Union countries exceeded the record figure of one billion for the first time. In 2018, according to Eurostat data, air traffic increased by a further 6% at European level, involving 1 billion 106 million passengers. In this European scenario, Italy is the fifth country in the EU ranking for the number of transported passengers, preceded in order by the United Kingdom, Germany, Spain and France, and is even in second place, preceded only by Spain, if referring to the transport of passengers on the national territory. In 2019, passengers transited through the 39 Italian airports monitored by Assaeroporti amounted to 193 million, i.e. 7.4 million more than the previous year equal to +4%, in line with the positive trend of previous years; among them, 19% on average were between 55 and 64 years old and 12% over 65 (Istat, May 2020). Together with the diversity of passenger population, it should be emphasized the change of their needs, helped by rapid technological development that allows passengers to carry out various activities from the comfort of their seats. Therefore, the heterogeneity of new transport needs makes it necessary to adopt an inclusive design approach, aimed at designing and implementing products that are accessible and usable by the largest number of potential users. The proposed research aims to support the ergonomic design of aircraft interiors in order to improve the quality of the mobility experience of both elderly passengers and passengers with reduced mobility. Specifically, the research started from the generation phase of their concept and went through the development of experimental protocols and methods for the evaluation of different design solutions and the continuous monitoring of postural comfort through temporal analysis of data collected by pressure and movement sensors. The research activity focused on the aspects of passive mobility, that is the context in which the air passenger operates (although the same can be extended to other contexts different from air transport, such as rail, sea or road transport): 1. identification of strategies and methods for assessing the accessibility and passenger comfort; 2. characterization of critical postural parameters to maximize passenger comfort; 3. elaboration of experimental protocols aimed at validating the feasibility of the proposed design solutions through experimental campaigns in real life. The activities related to the first point were carried out through an extensive analysis of the specialized literature concerning the analysis of (dis-)comfort both in aircraft environment and transport in general. The investigation then focused on methods for assessing the accessibility and (dis-)comfort of the passenger seat. Literature studies have focused most of the research activity on the evaluation and analysis of the experiences of young and healthy passengers who are able to move independently. Each study adopted different strategies preventing both comparison and generalization of results. Indeed, recent literature reviews have highlighted the need to develop methodologies for collecting and analyzing comfort data producing statistically significant evidence to provide diagnostic information to all stakeholders The activities inherent to the second point concerned the formulation of an evaluation strategy suitable to identify the needs of passengers, both young and old, and the critical features of the seat on which to intervene to maximize the comfort experience with respect to the functional characteristics of interest. These strategies were implemented during several experimental campaigns which, as described in the third point, involved the establishment of specific experimental protocols that allowed for replicability of the experimental tests and reliability of the results. In order to carry out the outlined activities, it was necessary to make use of different skills and tools. First of all, the experimental tests were designed with respect to appropriate methodologies for planning experiments (i.e. Design of Experiments, DOE) in order to minimize the number of tests and the impact of the main noise factors such as anthropometric characteristics of potential users, time and duration of the test. Two types of data were collected: subjective and objective measures. The collected subjective measures involved directly the selected sample who carried out an assessment of personally perceived (dis-)comfort, usability and accessibility (ease of ingress/egress) with respect to the conditions tested each time. The selected sample of participants was always sufficiently representative of the population of interest and was trained in advance to perform the test. To detect subjective measures, survey instruments such as questionnaires or checklists existing in the literature or specially elaborated and previously validated were used. The objective measures (i.e. pressure at the seat-occupant interface) were obtained using different instruments: mats equipped with sensors for both seat and backrest were used for the detection of pressures at the seat-occupant interface

Towards a hybrid comfortable passenger cabin interior for the flying V aircraft

The Flying-V is a V-shaped airplane in development, which uses less fuel due its form. Passengers are in the oval cabin in the wing, which asks for an alternative design to the interior. At the same time there is a demand for more comfortable interiors. 80 students were asked to develop interior design ideas for this Flying V concept. A jury of experts selected four aircraft interior concepts and these were developed and a 1:1 scale mockup was made, with a hybrid interior. It included a chaise longue seats, the group space, beds and ‘staggered’ seats for the middle of the Flying V interior. This was shown at a KLM 100 year event. 1692 visitors of the mock-up gave their preference and the chaise longue received most votes. In the discussions valuable comments from potential passengers were collected on the selected concepts giving input for further developments

Investigating subjective comfort with aircraft seat via ordinal regression model

In the scientific literature, the debate about how define and evaluate seat comfort is still open, but three points are not in question [1]: 1. comfort is a construct of a subjective nature; 2. comfort is affected by factors of various nature (physical, physiological, psychological); 3.comfort is a reaction to the environment. The subjective nature of the comfort experience is universally recognized; any comfort analysis cannot disregard subjective methods (‘directly asking people about how comfortable they are’), which can be regarded as the most direct way to detect subjective feelings of comfort and/or discomfort. This paper focuses on the assessment of aircraft seating comfort based on subjective comfort responses collected during laboratory experiments. During each experimental session, participants were asked to express their overall seat comfort perception and to evaluate specific seat design features. Comfort responses were analyzed with the aim to relate the perceived overall seat comfort to some design features, as well as to the user anthropometrical characteristics and feelings. The adopted statistical modeling approach is based on generalized linear mixed models. Differently from the traditional strategies used for the analysis of subjective sitting comfort data (e.g. correlation analysis, non-parametric hypothesis tests), the model-based approach allows to investigate and quantify the relationship between overall seat comfort and specific seat/user characteristics. The results show that the overall comfort perception is significantly influenced by age, lumbar support, height of seat pan and reclining

Robust Ergonomic Optimization of Car Packaging in Virtual Environment

Ergonomic design of automotive seat is a very challenging task whose results may directly influence driver’s comfort and safety. Seat comfort can be improved by identifying car-packaging solutions that allow an optimal driver’s posture. In order to reduce the time and cost for testing, ergonomic analysis is car- ried out in virtual reality (VR) environment with digital human models (DHM) that can be used to simulate the anthropometric variability of a target population of users and thus verify the robustness of design solutions with respect to the an- thropometrical noise factor. In this paper we illustrate a case study concerning the comfort improvement of a minicar packaging set up via robust ergonomic design (RED) with digital human models. The aim is the identification of the optimum levels for the seat control parameters that minimize the driver’s comfort loss with respect to a preferred posture. The approach adopted for the analysis of data ob- tained from the virtual experiments is based on the joint generalized linear model- ing of mean and dispersion of the driver’s postural comfort loss (i.e. the ergonom- ic response of interest)

Statistical Modelling of Comfort Preferences and Uncertainty in Subjective Evaluations of Aircraft Seat Comfort

Aircraft seat is rated as the most unsatisfying aspect of flying; under-standing the main factors impacting on passenger’s evaluations can provide a concrete opportunity for airlines to improve seat comfort and thus enhance pas-senger satisfaction and loyalty. Although there is a great deal of interest, the re-search on effective assessment strategies for subjective comfort is still underde-veloped. In this study a model-based approach for the analysis of subjective comfort data is suggested. The model adopted can be interpreted as a parametric version of the psychological process generating comfort ratings. The proposed approach is exploited through a case study concerning comfort assessment of aircraft seats designed for regional flights

Design and analysis of comparative experiments to assess the (dis-)comfort of aircraft seating

This paper focuses on the comparative assessment of comfort and discomfort (hereafter, (dis-)comfort) for air- craft seating. Subjective and objective data of seating (dis-)comfort were collected during an experiment in- volving 20 volunteers who tested 3 aircraft double-seats in upright and reclined position. In order to minimize experimental uncertainty due to well-known noise factors (i.e. patterns of discomfort during the work week and during the work day, order of evaluation, inter-individual differences), experimental trials were performed according to a crossover design. Statistical data analysis aimed mainly at investigating (dis-)comfort differences across seat conditions; gender-based differences in perceived discomfort on different body parts; effect of sitting duration on perceived discomfort on different body parts. The experimental results show that differences across seat conditions impacted differently on perceived discomfort depending on gender, body parts and sitting duration. No significant differences in perceived discomfort across gender were evident for the lightweight seat in both upright and reclined positions. On the contrary, for both baseline configurations, perceived discomfort at head and neck areas was higher for males than for females. For all seat conditions, participants experienced a significant worsening of perceived comfort over time at shoulders, back, sacrum and thighs and, in addition, at upper body area (i.e. neck, arm and forearm) and knees only for seats in reclined position

Comparative Assessment of Aircraft Seat (Dis)Comfort via Planned Experiments

Over the years, air traffic has been constantly increasing: in 2013, over 3 billion passengers were carried by the world’s airlines; according to a recent Airbus’ global market forecast, air traffic will double in the next 15 years, showing 4.7% annual growth between 2013 and 2034 (Airbus, 2016). Despite the growing demand, airlines are still one of the lowest-scoring industries in the American Customer Satisfaction Index (ACSI) and seat comfort is the most unsatisfying aspect of flying (ACSI, 2016). As a matter of fact, improving seat comfort can provide an opportunity to gain competitive edge in aircraft industry. This paper focuses on the assessment of aircraft seating (dis)comfort via a statistical-experimental approach. Seating (dis)comfort data (both objective and subjective) were collected during an experiment involving 18 volunteers (9 males and 9 females) who tested two aircraft seats in upright and upright/reclined configuration, respectively. Data were collected under controlled experimental conditions. In order to minimize experimental uncertainty due to well-known noise factors (i.e. patterns of discomfort during the work week and during the workday, evalua-tion sequence, inter-individual variability), experimental trials were performed according to a crossover de-sign. The whole experiment consisted of 54 experimental sessions; the duration of each session was approxi-mately 40 minutes. In each test run, the participant performed a fixed task so as to minimize differences in postures and control the effect of body posture upon pressure distribution at seat-interface. Statistical data analysis aimed at: 1) investigating gender–based differences in seating (dis)comfort; 2) identifying critical discomfort body areas; 3) analyzing time-variation in seating (dis)comfort. The experimental results are in line with the acknowledged hypotheses that males and females are exposed to different loading patterns and experience different discomfort pathways, due to fundamental biomechanical differences in their sitting pos-ture and anthropometric peculiarities. Moreover, results pinpoint that perceived discomfort increases signifi-cantly over time in several body areas

Statistics for Safety and Ergonomics in Design

The research aims at developing robust assessment and design strategies to support industrial engineers in the selection of optimal solutions for safety and ergonomics. It is realized through a successful integration of knowledge in experimental statistics, biomechanical modelling and advanced engineering design. The robust assessment and design strategies have been applied to the context of aircraft and automotive seat design, respectively. They rely on both physical and VR simulated experiments. In the former case, seat comfort is assessed via subjective perceptions and postural responses to seat exposures measured via interface pressure maps; whereas in simulated experiments, ergonomic evaluations are based on postural indexes based on joint angles. The adoption of the proposed strategies has provided interesting results in deepening the knowledge on seat ergonomics with focus on three main critical aspects: 1) differences in postural responses to seated exposures; 2) the impact of gender-based postural differences on objective measures of seat discomfort; 3) the usefulness of postural measurements (i.e. seat-interface pressure and joint angles) in finding significant differences in seat designs across different target populations of users

Towards a hybrid comfortable passenger cabin interior for the flying V aircraft

The Flying-V is a V-shaped airplane, which uses less fuel due its form. Passengers are in the oval cabin in the wing, which asks for an alternative design to the interior as the cabin is not in the flying direction. At the same time there is a demand for more comfortable interiors. 80 students were asked to develop interior design ideas for this Flying V concept. A jury of experts selected four aircraft interior concepts and these were developed and a 1:1 scale mockup was made, with a hybrid interior. It included chaise longue seats, the group space , beds and ‘staggered’ seats for the middle of the Flying V interior. This was shown at a KLM 100 years event. 1692 visitors of the mock-up gave their preference and the chaise longue received most votes. In the discussions valuable comments from potential passengers were collected on the selected concepts giving input for further developmentApplied Ergonomics and DesignIndustrial Design EngineeringFlight Performance and Propulsio

Osteoporosis's Menopausal Epidemiological Risk Observation (O.M.E.R.O.) study

Osteoporosis (OP) and related fractures are well-known severe conditions affecting quality of life and life expectancy of postmenopausal women, with high economic costs in Europe. On behalf of The Italian Society of Gynecology and Obstetrics (Società Italiana di Ginecologia ed Ostetricia, SIGO), the Osteoporosis's Menopausal Epidemiological Risk Observation (O.M.E.R.O.) study, a national multicenter study on clinical risk factors of OP was organized, using FRAX® tool as a reference. Here, data from this study are presented, showing an important portion of Italian postmenopausal women affected by osteopenia/OP at high risk of fracture and the need to do prevention and/or treatment. Gynecologist can be a primary specialist in this important challenge