Seat Adjustment Research Articles

REDESIGN OF BREASTFEEDING CHAIR FOR NURSERY ROOM

Breastfeeding chair is one of the essential facilities in the airport. This study designs the breastfeeding chair for the nursery room in Minangkabau International Airport. Quality Function Deployment (QFD) was used to investigate the customer requirements by distributing questionnaires to 100 mothers in Padang West Sumatra. Anthropometry data was also measured form those respondents. The study resulted in a design of ergonomic breastfeeding chair which was used features obtained from the voice of the customers. The design has considered the condition of the mother giving birth by normal as well as a cesarean. The design has an adjustable back seat with an angle of 95o,105o, and 110o; it has an adjustable footrest with 120o, 140o, and 180o angles. The chair has a headrest, baby support pad, a portable baby cushion, an adjustable baby bearings. The chair has also equipped with an assemble torn neck, a small drawer on the side of the chair, and a palm rest that can be used or not by adjusting the height.

Prevalence of non-nominal seat positions and postures among front-seat passengers

Objective Recent studies have suggested that a relationship exists between crash injury risk and occupant posture, particularly in postures different from those used with anthropomorphic test devices (ATDs) in crash testing. The objective of this study was to increase scientific understanding of typical front-seat passenger postures through a naturalistic study. Method Video cameras were installed in the passenger cabins of the vehicles of 75 drivers. Reflective targets were attached to the seats and the seat position and seat back angle was moved through their available ranges during instrumentation. The video data, along with vehicle acceleration and location data, were downloaded after the vehicles were operated as usual by their owners for two weeks. Video frames were manually coded to identify characteristics of front-seat passenger posture and position. Seat position and seat back angle were estimated using the calibration data obtained during vehicle instrumentation. Results Video frames from a total of 2733 trips were coded for 306 unique front-seat passengers. For these trips, a total of 13638 frames were coded; each frame represents about four minutes of travel time. The head was rotated left or right in 33% of frames, and the torso was rotated left or right about 10% of the time and pitched forward in almost 10% of frames. No seat position or seat back angle change was noted in 40 (53%) of vehicles and the distributions of seat position and seat back angle on arrival were essentially unchanged during travel. The seat was positioned full-rear on the seat track about 23% of the time and rearward of the mid-track position in 92% of frames. The mean seat back angle was 25.4 degrees (standard deviation 6.4 degrees); seat back angle was greater than 30 degrees in 15% of frames and greater than 35 degrees in less than 1% of frames. Conclusions This study is the first to report distributions of postures, seat positions, and seat back angles for front-seat passengers. Seat positions rearward of the middle of the seat adjustment range are common, but highly reclined postures are infrequent. Non-nominal torso and head postures also are nontrivial.

Comparative Analysis of Child Restraint Systems Safety Parameters in Relation to the New Regulation No. 129 of the Economic Commission for Europe of the United Nations (UN/ECE)

This study presents a comparison of the common Child Restraint Systems (CRS) which reduces the value of dynamic loads affecting the child’s body during car accidents. The analyzed systems were: child seats, booster seats, and straps—adjustable vehicle seat belts adapted to children’s stature. The effectiveness of the analyzed devices was assessed on the basis of experimental tests carried out in the accredited laboratory approving the Child Restraint Systems. The tests were carried out in accordance with the new Regulation No. 129 UN/ECE. The authors examined whether the tested devices meet the guidelines of the new Regulations No. 129 despite approval in accordance with Regulation No. 44. Based on the research results, better safety parameters of some new solutions dedicated to children’s safety could be observed. Almost all the selected CRS met requirements stated in Regulation No. 129. The only exception was for abdominal pressure in one of the tested devices. Head Resultant Acceleration in tested devices was 14.7–39.0% less than the limit determined in Regulation No. 129 whereas Chest Resultant Acceleration was 17.4–37.6% less. Abdominal pressure was 46.4–81.4% beneath the limit (apart from one case which did not meet the requirements). The HPC parameter (Head Performance Criterion) was 45.4–74.5% less. The final results show that there are still some possibilities for improving the safety of young vehicle passengers.

Investigating the influence of seating area design and enclosure on the seat-dip effect using scale model measurements

The low-frequency attenuation in the direct sound due to the concert hall seats, i.e., the seat-dip effect, is studied with the help of a scale model comprising an adjustable seating area and an enclosed box. More particularly, different seat underpass sizes and floor raking angles are studied, and the results are averaged over multiple source positions. With the measurements on the seating area only, the main seat-dip frequency is found to depend on the seat back rest height, and on the degree of obstruction of the seat underpass. The attenuation bandwidth is found to depend mainly on the floor raking. The differences become less clear when seating area is enclosed by concert hall walls and ceiling because the early reflections from the concert hall geometry compensate the low-frequency attenuation in the direct sound. In addition, the low frequencies below the main seat-dip frequency are found to increase in the presence of unobstructed seat underpasses, and such seats are recommended for the maximal bass response in a concert hall.

Everyday use of power adjustable seat height (PASH) systems

ABSTRACT The objective of this study was to measure how, why, and where the power adjustable seat height (PASH) system of Quantum’s iLevel® wheelchairs were used. We instrumented iLevel® power wheelchairs for 24 adults to measure wheelchair occupancy, seat height, in-seat activity level, and bouts of mobility. Participants elevated their wheelchair 3.9 (4.4) (mean (SD)) times per day, including 1.0 (1.6) times per day past 9”. Twenty-nine percent of elevation events were transient, lasting < 1 min, while 42% of elevate events lasted >5 minutes. Sixty-seven percent of participants transferred while elevated at least once, typically from heights <5” or >9”, and 14 people changed their seat height between the transfer to and from the wheelchair. Twenty-three of 24 participants wheeled while elevated. Finally, in-seat activity level was greater while elevated. For many participants, the PASH system provided a functional benefit on a daily basis. Individuals elevated 4 times per day for activities including transfers, reach, gaze, or mobility. However, 14 participants did not elevate on at least 1 day. Further study is needed to identify the characteristics of people who will benefit most from a PASH system as well as to document the value associated with PASH system use.

Exploring the lived experience of people using ultralight wheelchairs with on-the-fly adjustable seating function

Introduction: Manual wheelchairs with spontaneous, user-initiated seating adjustability allow users to independently adjust both rear seat height and backrest angle on-the-fly to optimize positioning for various activities throughout the day.Purpose: This study aimed to examine the lived experience of users of wheelchairs with user-initiated seating adjustability and investigate the impact of this functionality in their day-to-day lives.Methods: This exploratory study involved eight participants who used manual wheelchairs with spontaneous, user-initiated adjustability. Participants engaged in semi-structured qualitative interviews, during which they were asked general open-ended questions about a typical day using their wheelchair, as well as specific questions addressing day-to-day usage, activity participation, and unique seating applications and situations where adjustments were used.Results: Our analysis identified three primary themes: (1) “New Angles on Function and Participation” revealed the impact adjustments had on physical function and participation; (2) “Comfort to Reach New Heights” described experiences related to positioning for comfort, and comments related to convenience and general usability; and (3) “Elevating Health and Social Standing” identified perceived effects of the wheelchair on user health and psychosocial parameters such as social interactions and self-esteem.Conclusions: Our study indicates that adjustable seating can have a significant impact on ultralight wheelchair users. Results may help with prescription of this class of wheelchair, and may also provide potential users and therapists some insight into the range of applications and benefits of on-the-fly adjustment features.Implications for rehabilitationFunctional ability can be improved through the use of on-the-fly adjustable seating functions, leading to heightened participation at home and in the community.Users of wheelchairs with adjustable seating experience psychosocial benefits including increased social interaction and social inclusion.Clinicians and consumers may want to consider the functions that are impacted by adjustable seating as a method of improving reach, transfers, comfort and social interactions of manual wheelchair users.

DESAIN SLIDE ADJUSTER KURSI TRUK MENGGUNAKAN METODE TRIZ

The increasing competition in the selling price of the vehicle makes the OEM lot of cost reduction programs to obtain competitive prices. The OEM's main program is to provide handling of product design to production to suppliers. One of its products is the slide adjuster of truck seats. The difficulties encountered by local suppliers are complex design, lack of product knowledge and new players. In an effort to answer the challenge, the supplier uses TRIZ method to create the design concept. The results of the design concepts obtained can provide price reductions due to the results of function analysis can be done component reduction. The decision is based on the result of different component functions and patent study. For structural strength of the slide adjuster verification with CAE with maximal 357.4 MPa stopper strength in bracket lock. Rattle slide obtained maximum 2.775 mm y direction. Slide load obtained 82.5 N. TRIZ method can effectively be used to design slide truck seat adjuster products.

Dynamics analysis and simulation of a new 6-DOF lower limb rehabilitation robot

This paper proposes a new hybrid (parallel–serial) 6-DOF lower limb rehabilitation robot including two mechanical legs and an adjustable seat, which could train in sitting, lying and standing three postures. Each mechanical leg consists of hip joint, knee joint and ankle joint. The dynamics and DOF of the robot are analysed, and the result is verified by the software ADAMS. The result lay the foundation for prototype build in future.

Manufacturing custom-contoured wheelchair seating: A state-of-the-art review.

Custom-contoured wheelchair seating lowers risk of pressure injury and postural deterioration while custom-contoured wheelchair seating lowers risk of pressure injury and postural deterioration while increasing the stability and functional activity of the wheelchair occupant. Producing custom-contoured seating systems has historically been a labour-intensive process custom-contoured seating systems is historically labour-intensive. Evaluate the strengths and limitations of current manufacturing processes for custom-contoured wheelchair seating to suggest potential future manufacturing processes. Literature review of the state of the art. Research conducted through a literature review focused on the performance of different types of custom-contoured wheelchair seating products and processes over the last 40 years. Recent literature in orthotics and prosthetics was also consulted to assess future trends in seating. There are five main manufacturing processes currently used to produce custom-contoured wheelchair seating systems. No single process is yet suitable for all wheelchair users, but many manufacturers are transitioning to computer numerical controlled (CNC) milling to reduce manual labour. Adjustable micro-modular seating and moulded seat insert manufacturing are also prevalent and offer alternative seating to soft foam carving. There is a need in the custom wheelchair seating sector for processes that are fast, cost-effective, produce little to no material waste, and that can effectively maintain a comfortable seating micro-climate. Additive manufacturing may meet these criteria, but further evaluation is required. This review suggests that the custom-contoured wheelchair seating manufacturers are moving away from labour-intensive processes towards digital techniques, like CNC foam milling. Additive manufacturing is a potential new process that may reduce overall costs, the lead time in preparing seats and has the potential to better manage the seating micro-climate.

Researching of commonalities and differences in cold forging of spur and helical gears

Modern automobiles are equipped with a large number of gear transmissions. In the powertrain, for example, they are used as multi-stage manual transmissions and in the interior for mirror and seat adjustment. Machining manufacturing processes—like gear hobbing and shaping—represent the state of the art in gear manufacturing due to high manufacturing accuracy and flexible machining possibilities. With regard to economic, ecological and technical aspects, cold forging offers a promising production technology. In conventional transverse and forward extrusion processes, the ejection process is a challenge due to high forces and a negative influence on the gearing accuracy. One variant of forward extrusion is the so-called “Samanta” process, whereby an additional ejection step is avoidable by sequential forming of the gears. For the establishment of this process in industry, the increase of the achievable gearing accuracy and the achievable tool life is of major relevance. Thus, a deeper process understanding as well as knowledge about the influences on the process results is beneficial. In this context, the aim of this research work is to produce spur and helical gears by the “Samanta”-process. In addition to the resulting component properties, the characteristics of the process are determined. On this basis, commonalities and differences in cold forging of spur and helical gears are investigated to gain a principle process understanding. These findings are also used to derive possible approaches for improving component and process properties in future research work. The results reveal that cold forging of spur and helical gears by the “Samanta”-process results in characteristic properties and specific challenges within the gear types. Furthermore, a geometric adaptation in the gearing area of the used die promises enormous potential for a positive influence on the process results for both types of gearing.

Enhanced application limits for crossed helical gearboxes using new geometries for smaller sliding paths or smaller contact pressures

Crossed-axis helical gear units are used as actuators and auxiliary drives in large quantities in automotive applications such as window regulators, windscreen wipers and seat adjusters. Commonly gear geometry of crossed helical gears is described with one pitch point. This article deals with an extended calculation method for worm gear units. The extended calculation method increases the range of solutions available for helical gears. In general, for a valid crossed helical gear pair, the rolling cylinders do not have to touch each other. In mass production of many similar gears, individual gears can be reused because they can be paired with other centre distances and ratios. This also allows the use of spur gears in combination with a worm, making manufacturing easier and more efficient. By selecting design parameters, for example the axis crossing angle or the helix angle of a gear, positive effects can be achieved on the tooth contact pressure, the overlap ratio, the sliding paths, the lubrication condition, the tooth stiffness and, to a limited extent, on the efficiency of the gearing. It can be shown that for involute helical gears, in addition to the known insensitivity of the transmission behaviour to centre distance deviations, there is also insensitivity to deviations of the axis crossing angle. This means that installation tolerances for crossed helical gearboxes can be determined more cost-effectively.

Researches on the ergonomic design of the workplace for the car driver profesion

Ergonomic design of the workplace is a matter of utmost importance. Ergonomics should consider reducing the high number of accidents as well as the high amounts paid for insurance. In recent years there have been numerous injuries due to cumulative trauma or due to psychological, sociological and ethical factors. Operators often adapt to improper work conditions, but the number of accidents increases and productivity decreases. The driver of the vehicle must be provided with a suitable space and position so that his posture is physiologically comfortable, does not cause excessive fatigue and illness, there is freedom of movement to drive the steering wheel, steering levers and pedals, which must be accessible and placed in such a way that the driver’s requirements are minimal and the visibility is ensured. In the paper there will be presented elements for the ergonomic design of the workplace for the motor vehicle occupation and will be taken into account several factors involved among which we mention the correct positioning of the seat adjustment while driving a car, adjusting the backrest and seat, adjusting the lumbar support, adjusting the steering position, adjusting the headrests to ensure that in the event of an accident, the risk of a head injury is very small.

Effect of reclining angle on lumbar lordosis at driving posture: A radiological evaluation.

Optimal seatback angles for automobile drivers' seats have been investigated based on comfort and back muscle activities; however, radiology supported evidences are scarce. The aim of this study was to evaluate optimal range of the seatback reclining regarding torso angles for an automobile driver's seat to preserve lumbar lordosis. Thirty-one healthy volunteers were recruited among five body type categories. Lateral lumbar spine X-rays were obtained for the neutral sitting posture without seatback (reference), and with reclining angles of 23∘ to 33∘ by 2∘ intervals. The Cobb angles for the L1-L4, L4-S1, and L1-S1 segments were measured. The Cobb angle for L4-S1 was nearest to the reference (18.74 ± 1.57∘, mean ± standard error mean) at reclining angles of 29∘ and 31∘ (14.51 ± 1.41∘ and 14.47 ± 1.43∘, respectively). The Cobb angle at L4-S1 between reclining angles of 27∘(12.02 ± 1.31∘) and 29∘ (14.51 ± 1.41∘) were significantly different (p< 0.001). Tall men showed relatively preserved lordosis angles at all reclining angles. Fat men and short women demonstrated prominent loss of lordosis with excessively kyphotic L1-L4 segment. Reclining angles of 29∘ to 31∘ revealed to be optimal for preserving lordosis at the L4-S1 segment. Individualized healthcare-related guideline for driver's seat adjustment setting is necessary.

Speaker identification and its application in automobile industry for automatic seat adjustment

In this paper, an application of speaker identification in automobile industry is proposed. The work is divided into two main categories. The first part deals with the task of speaker identification where a system is trained and tested for multiple users using a database of isolated Hindi digits and Hindi sentences. A hybrid new algorithm is used for speaker identification which captures the benefits of both LPC and MFCC feature extraction technique. The new proposed technique shows an improvement of 2.05% over conventional MFCC features for isolated Hindi digits and 12.41% for Hindi sentences. It also shows an improvement of 53.26 over LPC for Hindi sentence and 32.51% for isolated Hindi digit over LPC. The proposed features were also tested for real time noisy environment by adding speech and F16 noise to test voice samples with varying degree of distortion starting from 0 to 20 dB. The second part describes the interfacing techniques and design of the hardware configuration for seat adjustment. The proposed model is designed using MATLAB. Speech samples from users are recorded through a microphone. Different features of this wav file are evaluated and fed into the model generated during testing phase. Depending on outcome from the classifier, a user is identified. Once the user is successfully identified, signals are sent to the servo motor through arduino microcontroller interfaced through MATLAB to automatically adjust the driver’s seat.

How does relaxing posture influence take-over performance in an automated vehicle?

The driver will not have to constantly monitor the vehicle while driving in a level-3 automation or at a higher level (SAE International, 2016), which enables the driver to conduct different activities and be out of the control loop. To achieve the goals of non-driving related tasks (NDRTs) rather than the driving task better, the driver may take other sitting positions, defined as “non-driving postures (NDPs)”. Different pos-tures represent different driver motoric states. This may result in different reactions to a take-over request (TOR). In this work, relaxing NDPs are built by manipulating the driver’s knee angle (133°) and torso an-gle (38°) via seat adjustments. Their take-over performances of each posture are evaluated. The torso angle is identified as a significant influencing factor: the reclined driver takes over more poorly, whereas a larger relaxing knee angle does not affect take-over performance if the heel is able to contact the pedal.

Design, Modeling and Simulation of a Reconfigurable Wheelchair with Stand-sit-sleep Facilities

Standing feature of the wheelchair allows the disabled to be able to reach different heights and thus gives enhanced navigations in different conditions. Wheelchair with back seat adjustment helps in health preservation as well as daily living activities including trunk positioning, functional enhancement stability and gait balance. Thus, paper presents the design, modeling and simulation of a reconfigurable wheelchair with stand-sit-sleep facilities. Key areas focused on maximizing safety, optimizing the size with minimizing cost and weight of the newly designed wheelchair. The contribution of paper are (i) Kinematic concept of the reconfigurable wheelchair (ii) Synthesis of the proposed wheelchair mechanism (iii) CAD modeling using the Top down modeling approach (iv) Multi-body dynamics Simulation and stress simulation of model. Wheelchair design has been analyzed and verified by using MSC ADAMS and ANSYS simulation tools. The developed model will help in improving the functional capabilities of wheelchair users allowing enhanced independence and quality of life (QoL).

Development and Evaluation of a Computational Human Performance Model of In-vehicle Manual and Speech Interactions

Usability evaluation traditionally relies on costly and time-consuming human-subject experiments, which typically involve developing physical prototypes, designing usability experiment, and recruiting human subjects. To minimize the limitations of human-subject experiments, computational human performance models can be used as an alternative. Human performance models generate digital simulations of human performance and examine the underlying psychological and physiological mechanisms to help understand and predict human performance. A variety of in-vehicle information systems (IVISs) using advanced automotive technologies have been developed to improve driver interactions with the in-vehicle systems. Numerous studies have used human subjects to evaluate in-vehicle human-system interactions; however, there are few modeling studies to estimate and simulate human performance, especially in in-vehicle manual and speech interactions. This paper presents a computational human performance modeling study for a usability test of IVISs using manual and speech interactions. Specifically, the model was aimed to generate digital simulations of human performance for a driver seat adjustment task to decrease the comfort level of a part of driver seat (i.e., the lower lumbar), using three different IVIS controls: direct-manual, indirect-manual, and voice controls. The direct-manual control is an input method to press buttons on the touchscreen display located on the center stack in the vehicle. The indirect-manual control is to press physical buttons mounted on the steering wheel to control a small display in the dashboard-cluster, which requires confirming visual feedback on the cluster display located on the dashboard. The voice control is to say a voice command, “ deflate lower lumbar” through an in-vehicle speaker. The model was developed to estimate task completion time and workload for the driver seat adjustment task, using the Queueing Network cognitive architecture (Liu, Feyen, &amp; Tsimhoni, 2006). Processing times in the model were recorded every 50 msec and used as the estimates of task completion time. The estimated workload was measured by percentage utilization of servers used in the architecture. After the model was developed, the model was evaluated using an empirical data set of thirty-five human subjects from Chen, Tonshal, Rankin, &amp; Feng (2016), in which the task completion times for the driver seat adjustment task using commercial in-vehicle systems (i.e., SYNC with MyFord Touch) were recorded. Driver workload was measured by NASA’s task load index (TLX). The average of the values from the NASA-TLX’s six categories was used to compare to the model’s estimated workload. The model produced results similar to actual human performance (i.e., task completion time, workload). The real-world engineering example presented in this study contributes to the literature of computational human performance modeling research.

End user evaluation of a Kneeling Wheelchair with “on the fly” adjustable seating functions

A “kneeling” ultralight wheelchair prototype has been developed that allows users to adjust seat position “on the fly” for different activities throughout the day. The wheelchair includes independent adjustment functions for rear seat height, front seat height (“kneeling”) and backrest angle. Aim: This work aimed to gather feedback about the wheelchair’s functionality and performance through end user evaluation trials. Methods: Eight manual wheelchair users evaluated the prototype Kneeling Wheelchair for a range of activities. User perspectives on parameters such as usability, comfort, stability and effectiveness were obtained through both open-ended and Likert-scale rating questions. Results: Results indicate several potential benefits of the adjustment functions of the Kneeling Wheelchair. Rear seat height adjustment may facilitate a number of activities of daily living, as well as provide benefits for comfort and social interactions. Back rest adjustment may increase comfort and stability on slopes. Front seat height adjustment may be beneficial for transfers and conducting sustained low-to-the-ground activities. While benefits of this adjustment function were described by many participants, some struggled with usability of the kneeling mechanism and rated this function less favourably than the other two. Conclusion: The findings of this study will inform future iterations of the Kneeling Wheelchair design and may spur future developments in wheeled mobility. In the long-term, it is anticipated that novel wheelchair solutions, such as the one described in this paper, may support improved health, quality of life and community participation for people with mobility impairments.Implications for rehabilitationWheelchairs that allow users to easily adjust seat and backrest position “on the fly” to better suit different tasks throughout the day may provide benefits such as facilitating activities of daily living.A front seat height adjustment feature on a new wheelchair prototype may be beneficial for transfers and conducting sustained low-to-the ground activities.End user evaluations can provide valuable insight to direct future design modifications and innovation.

Ergonomic evaluation of a new truck seat design: a field study

A postural evaluation of commercial licensed truck drivers was conducted to determine the ergonomic benefits of a truck seat prototype in comparison with an industry standard seat. Twenty commercially licensed truck drivers were recruited to perform a 90-min driving task. Postures were assessed using accelerometers and a backrest and seat pan pressure mapping system. Subjective discomfort measurements were monitored using two questionnaires: ratings of perceived discomfort (RPD) and the automotive seating discomfort questionnaire (ASDQ). Participants reported significantly higher discomfort scores when sitting in the industry standard seat. Participants sat with more lumbar lordosis and assumed a more extended thoracic posture when seated in the prototype. Pairing the gluteal backrest panel with the adjustable seat pan also helped reduce the average sitting pressure on both the seat pan and the backrest. The prototype provided several postural benefits for commercially certified truck drivers, as it did for a young and healthy population.

Evaluation of Pilot’s Seat Design of Civil Aircraft for Indian Anthropometric Data by using Delmia Human Software

Pilot seat comfort is an essential factor in the civil aviation industry. The evaluation of seat design using flight simulator is cost prohibitive. Data-driven simulation software may solve this issue. The objective of this study was to find optimum parameters of pilot seat adjustment for a different percentile of pilot’s population. Anthropometry is one of the critical aspects in determining the design of cockpit layout. Until now, the design of pilot seats of civil aircraft has mainly focussed on anthropometry of pilots residing in western countries. However, time spent by Indian pilots while sitting on inadequately designed seats might cause back pain and musculoskeletal disorders due to improper posture. This study aimed to evaluate the effect of pilot’s seat adjustment parameters of civil aircraft on Indian pilots by using Delmia Human v6 software. Seat model and cockpit environment used in the simulation was developed using the dimensions from the manual of selected aircraft. Anthropometric data of 100 pilots from different regions of India were collected. Manikins were customized based on 5th, 50th and 95th percentile of collected data were created in Delmia v6 software and then imported into the virtual environment for simulation. The compression and shear forces at l4/l5 vertebrae were calculated by using the biomechanical analysis module of the software. The optimal combinations of the seat adjustment feature were obtained for a different set of pilot population.