This paper reports on the development and validation of an automated seat-dimension extraction system that can efficiently and reliably measure the SAE J2732 (2008) seat-dimensions from 3D seat scan data. The automated seat-dimension extraction process in the system consists of four phases: (1) import 3D seat scan data along with seat reference information such as H-point location, seatback and cushion angles, (2) identify centerline and lateral cross-section lines on the imported 3D seat scan data, (3) identify landmarks on the centerline and cross-section lines based on the SAE J2732 definitions, and (4) measure seat-dimensions using the identified landmarks. To validate the automated seat measurements, manually measured dimensions in a computer-aided-design (CAD) environment and automatically extracted ones in the current system were compared in terms of mean discrepancy and intra- and inter-observer standard deviations (SD).
A preventive evaluation of perceived postural comfort in car-cockpit design: differences between the postural approach and the accurate muscular simulation under different load conditions in the case of steering-wheel usage.
The evaluation of perceived comfort inside a car, in the early stages of design process, is still an open issue. Modern instruments like CAE (Computer Aided Engineering) and DHM (Digital Human Modeling) already offer several tools for a preventive evaluation of ergonomics parameters for car drivers through the use of detailed CAD (Computer Aided Design) models of car-interiors and by the multi-body approach for evaluating movements and interactions. Nevertheless, it is not enough because the subjectivity of comfort perception is due to parameters that are very difficult to be evaluated in the early stage of design and need “hard-prototypes” that, often, are too expensive to be realized. In the latest 30 years, several researchers tried to develop methods to objectivize the comfort performance but most of them are based on questionnaires, marketing researches, physiological and biomechanical analyses, and need devices or interactions that modify the perceived comfort.
The ability to independently transfer into and out of a vehicle is essential for many wheelchair users to achieve driving independence. This paper presents the results of an exploratory study that investigated the transfer strategies of wheelchair users who drive from their driver’s seat and not from their wheelchair. The goal of this study was to identify typical ingress and egress motions as well as “touch points” of wheelchair users transferring into and out of the driver’s seat. While motion databases exist for the ingress and egress of able-bodied drivers, this study provides insight on drivers with physical disabilities. Twenty-five YouTube videos of wheelchair users who transferred into and out of their own sedans were analyzed.
The paper is focused on both the the subjective and the objective ride comfort of farm tractors. The experimental measurement of the relevant accelerations occurring at the tractor body, at the cabin and at the seat was performed on a number of different farm tractors. A subjective rating of the ride confort was performed. The comfort index was computed according with ISO 2631 and other standards. The acceleration of the seated subject was computed by means of a proper mechanical model of farm tractor and derived at different positions on the subject body. It turned out that the acceleration of the lower torso was particularly relevant for establishing a matching between the subjective perception and the objective measurement and computation. A number of indices have been derived from the measured data which are able to correlate the subjective drivers' feeling with the measured accelerations.
Automotive seats are commonly described by one-dimensional measurements, including those documented in SAE J2732. However, 1-D measurements provide minimal information on seat shape. A 3-D scanner may provide high-resolution details, but due to inconsistent vertex and polygon compositions, indexing and comparing geometries across different seats are extremely difficult. The goal of this work was to develop a statistical framework to analyze and model the surface shapes of seats by using similar techniques that have been used for modeling human body shapes. The 3-D contour of twelve driver seats of sedans and pickup trucks were scanned and aligned, and 332 landmarks were identified using a semi-automatic process. A template mesh of 18,306 vertices was morphed to match the scan at the landmark positions, and the remaining nodes were automatically adjusted to match the scanned surface. A principal component (PC) analysis was performed on the resulting homologous meshes.
In-vehicle Driving Posture Reconstruction from 3D Scanning Data Using a 3D Digital Human Modeling Tool
Driving posture study is essential for the evaluation of the occupant packaging. This paper presents a method of reconstructing driver’s postures in a real vehicle using a 3D laser scanner and Human Builder (HB), the digital human modeling tool under CATIA. The scanning data was at first converted into the format readable by CATIA, and then a personalized HB manikin was generated mainly using stature, sitting height and weight. Its pelvis position and joint angles were manually adjusted so as to match the manikin with the scan envelop. If needed, a fine adjustment of some anthropometric dimensions was also preceded. Finally the personalized manikin was put in the vehicle coordinate system, and joint angels and joint positions were extracted for further analysis.
Many studies have been conducted and supporting literature has been published to better understand thermal comfort for the automotive environment, particularly, for the HVAC system within the cabin. However, reliable assessment of occupant thermal comfort for seating systems has lacked in development and understanding. Evaluation of seat system performance in terms of comfort has been difficult to quantify and thus most tests have been established such that the hardware components are tested to determine if the thermal feature does no harm to the customer. This paper evaluates the optimal seat surface temperature to optimize human thermal comfort for an automotive seating system applications. The physiological responses and comfort obtained from human subjects are compared to seat surface temperatures & quality data verbatim responses of the seats.
Law enforcement officers (LEO) make extensive use of vehicles to perform their jobs, often spending large portions of a shift behind the wheel. Few LEO vehicles are purpose-built; the vast majority are modified civilian vehicles. Data from the field indicate that LEO suffer from relatively high levels musculoskeletal injury that may be due in part to poor accommodation provided by their vehicles. LEO are also exposed to elevated crash injury risk, which may be exacerbated by a compromise in the performance of the occupant restraint systems due to body-borne equipment. A pilot study was conducted to demonstrate the application of three-dimensional anthropometric scanning and measurement technology to address critical concerns related to vehicle design. Detailed posture and belt fit data were gathered from five law enforcement officers as they sat in the patrol vehicles that they regularly used and in a mockup of a mid-sized vehicle.
Ergonomics Evaluation of In-car Occupant Posture with Indian Specific Usage Pattern Virtual assessment of an occupant posture ergonomics has become an essential part of vehicle development process. To design vehicle for different market is one of the primary reason for manufacturers using digital tools to address the specific needs of the target market such as cultural background, road and traffic conditions. Ergonomics software like RAMSIS allows manufacturers to asses design with unique customer requirements in product design. Defining these requirements with RAMSIS human module helped development team to accurately define occupant targets such as occupant space, visibility and reach-ability etc. This paper defines the methodology to develop, create and adopt Indian behavior and usage patterns in vehicle development process.
Seating comfort is associated with the various factors and one of the principal components of a vehicle environment which can affect passenger’s comfort is vibration. The seat design plays a vital role in the vibration isolation as it is directly in contact with human body. Vibration isolation properties of a seat depend upon its dynamic parameters such as cushion, spring stiffness, and damping of seat suspension. In recent years, automotive seat designers are paying more attention for the improvement of seat cushion properties. This paper provides information about a new automotive seat concept which use double-wall 3D air mat in cushion along with foam cushion. The air-mats base fabrics are interlinked with numerous spacer threads to make a 3D structure. An optimization-based method is used to determine the optimal seat dynamic parameter for cushion (particularly for double-wall 3D air mat) based on minimizing occupant’s body discomfort.
Off-highway hybrids: Opportunities and challenges With oil prices declining and emissions regulations in North America 'stabilized,' is there a place for hybrid powertrains in this new world of cheap oil? Looking for a better image Display advances are helping to reduce operator fatigue. Charging up electrified powertrains Control technologies race forward while batteries improve and adopt standard sizes. Measuring and accounting for suspension TARDEC teamed with SEA Ltd. to develop a system to measure the suspension parameters, center of gravity, and moments of inertia of wheeled vehicles in the never ending quest to model and predict vehicle dynamic behavior. Looking at mobility in 2050 Cuneyt L. Oge begins his term as 2016 SAE International President with a vision about the future of auto- and aero-mobility.
Develop and propagate recommended practices for the design, development, testing and implementation of head worn displays in piloted airborne platforms
Abstract Driving posture measurement is essential for the evaluation of a driver workspace and for improved seat comfort design. This study captures the comfortable driving postures for Koreans using a handheld portable Artec L™ 3D scanner. Subjects consisted of 20 healthy individuals (10 males and 10 females) ranging in age from 20 to 40 years and grouped as three weight groups (<59 kg, 60-79 kg and >80 kg). Eighteen land markers were attached (car seat: 9 markers; subject: 9 markers). From the 3D scanned data, the angles (neck, back, headrest, seat back, wrist, elbow, knee, and ankle) and distances (head to headrest, seat height, and seat back and forth) between the land markers were extracted in the Rapidform XOR software. The body pressure distribution was measured using two pressure mats from 17 body part regions. The measured pressure data were analyzed for average pressure, contact area, and body part pressure ratio.
This document describes the design and assembly force guidelines for conventional shipping caps, torque caps, and body plugs. All possible design and applications could not be anticipated in creating these guidelines. Where there are questions of adherence to to this document, such as use of an “off-the-shelf” design, always consult the responsible Ergonomics Department.
This document describes the assessment methods and physical requirements associated with the manual handling of carts and dollies, specific to material handling systems. All possible designs and applications could not be anticipated in creating these guidelines. Where there are questions of adherence to this document, such as use of an "off-the shelf" design, always consult the responsible Ergonomics Department. Force guidelines were primarily developed referencing the push/pull psychophysical Snook data contained in A Guide to Manual Materials Handling (second edition) by Mital, Nicholson and Ayoub (NY: Taylor & Francis, 1997). The force guidelines accommodate 75% of female capabilities and 99% of male capabilities. Factors that were included in the established guideline include: push / pull distances, vertical hand height, horizontal hand height, frequency and wheel / castor alignment and load rating. These factors were used to develop a conservative force guideline.
This document describes the design, assessment methods and physical requirements associated with material handling systems. This would include, but not limited to manual dollies, small lot systems and kitting. All possible designs and applications could not be anticipated in creating these guidelines. Where there are questions of adherence to this document, such as use of an “off-the shelf” design, always consult the responsible Ergonomics Department.
This SAE Recommended Practice describes two-dimensional 95th percentile truck driver side view, seated stomach contours for horizontally adjustable seats (see Figure 1). There is one contour and three locating lines to accommodate male-to-female ratios of 50:50, 75:25, and 90:10 to 95:5.
This SAE Recommended Practice describes two-dimensional, 95th percentile truck driver, side view, seated shin-knee contours for both the accelerator operating leg and the clutch operating leg for horizontally adjustable seats (see Figure 1). There is one contour for the clutch shin-knee and one contour for the accelerator shin-knee. There are three locating equations for each curve to accommodate male-to-female ratios of 50:50, 75:25, and 90:10 to 95:5.
Abstract Bus and coach drivers spend considerably more time in the vehicle, compared to an average personal car user. However, when it comes to comfort levels, the personal cars, even the inexpensive hatchbacks score much higher than a standard bus. This is because the amount of ergonomic design considerations that go into designing a car's DWS (driver workspace) is much more than that of buses. To understand this lacuna, the existing standards and recommendations pertaining directly or remotely to bus driver workspace were studied. It was understood, beyond certain elementary recommendations, there were very few standards available exclusively for buses. This paper ventures to establish a set of guidelines, exclusively for designing bus and coach driver workspace. The various systems in the driver's work space and their relevance to driver's ergonomics are discussed. References are drawn from different case studies and standards to come up with recommendations and guidelines.
Abstract Operating in an increasingly competitive market, buses and agricultural equipment are facing the changes that passed trucks and commercial vehicles. Those changes are affecting drastically the final cost of the product and consequently its relationship with the costumer. This constant for more competitive prices drives the companies to develop more aggressive strategies of components standardization on a global level, leading to the emergency of global products in regional applications, keeping regional particularity characteristics when operating in the field. In the bus market, it is confirmed that in various media and academic publications there are recurrent complains about driver comfort by several factors related from the ergonomics of the workplace, as well as with operators from agricultural implements.
Applying Design for Assembly Principles in Computer Aided Design to Make Small Changes that Improve the Efficiency of Manual Aircraft Systems Installations
Abstract The installation of essential systems into aircraft wings involves numerous labour-intensive processes. Many human operators are required to perform complex manual tasks over long periods of time in very challenging physical positions due to the limited access and confined space. This level of human activity in poor ergonomic conditions directly impacts on speed and quality of production but also, in the longer term, can cause costly human resource problems from operators' cumulative development of musculoskeletal injuries. These problems are exacerbated in areas of the wing which house multiple systems components because the volume of manual work and number of operators is higher but the available space is reduced. To improve the efficiency of manual work processes which cannot yet be automated we therefore need to consider how we might redesign systems installations in the enclosed wing environment to better enable operator access and reduce production time.
This SAE Aerospace Standard (AS) covers the requirements and technical guidance for evaluation of life-cycle cost, productivity, and safety/health factors related to power hand tool selection. It applies approaches to selection of quieter and lower vibration hand-held powered tools, with optimal ergonomic features, for the prevention of Hand-Arm Vibration Syndrome (HAVS), hearing loss and repetitive motion injuries. It suggests use of noise and vibration data provided by vendors to be verified and supplemented by information available through the National Institute for Occupational Safety and Health (NIOSH) and European Union databases. Inclusion/exclusion of data in this document is not intended to imply that all of the products described herein are the only production models that meet this standard. Consumers are requested to consult with manufacturers concerning lists of stock production models that meet this standard.
This SAE Standard is intended to be used as a guide for manufacturers and users of general purpose industrial machines to provide a reasonable degree of protection for personnel during normal operation and servicing. This document excludes skid steers which are covered by SAE J1388. Avoidance of accidents also depends upon the care exercised by such persons (see SAE J153). Inclusion of this standard instate, federal, or any laws or regulations where flexibility of revision is lacking is discouraged.
The guidelines for operator and bystander protection in this recommended practice apply to towed, semimounted or mounted flail mowers and flail power rakes when powered by a propelling tractor or machine of at least 15 kw (20 hp), intended for marketing as industrial mowing equipment and designed for cutting grass and other growth in public use areas such as parks, cemeteries and along roadways and highways. The use of the word "industrial" is not to be confused with "in-plant industrial equipment". This document does not apply to: 1. Turf care equipment primarily designed for personal use, consumption or enjoyment of a consumer in or around a permanent or temporary household or residence. 2. Machines designed primarily for agricultural purposes but which may be used for industrial use. 3. Self powered or self propelled mowers or mowing machines.
This SAE Standard establishes performance criteria for towed, semi-mounted, or mounted and arm type rotary mowers with one or more blade assemblies of 77.5 cm blade tip circle diameter or over, mounted on a propelling tractor or machine of at least 15 kW, intended for marketing as industrial mowing equipment and designed for cutting grass and other growth in public use areas such as parks, cemeteries, and along roadways and highways. The use of the word “industrial” is not to be confused with “in-plant industrial equipment.” This document does not apply to: a. Turf care equipment primarily designed for personal use, consumption, or enjoyment of a consumer in or around a permanent or temporary household or residence. b. Equipment designed primarily for agricultural purposes but which may be used for industrial use. c. Self-powered or self-propelled mowers or mowing machines.
This SAE Recommended Practice describes how to position and posture the H-point design tool (HPD) described in Appendix B, and how to establish the seating reference point (SgRP), design H-point travel path, and other key reference points that are used in the design and specification of both driver and passenger seat positions. This practice also provides a method for determining the length of the seat track for a driver seat that adjusts fore/aft. The seat track length is based on a desired level of driver accommodation, assuming a U.S. population containing an equal number of male and female drivers. The procedure can be used to establish driver seat track accommodation for new vehicle designs or to evaluate accommodation in existing vehicles. A general method for determining driver seat track length for any driver population (male and female stature distribution) at any selected accommodation percentile and gender mix is given in Appendix A.
This document provides dimension definitions that facilitate geometric quantification and evaluation of seats. This document has been designed for use in CAD, however, many dimensions require establishing HPM position and attitude. Refer to the appropriate document for these procedures. These dimensions are package independent in that they do not require use of the HPM-ll supplemental thigh/leg/shoe. Three types of seat geometry reference points and measurements have been developed. 1. Simple reference points and measurements not related to H-point 2. H-point dependent reference points and measurement that utilize the seat characterization capabilities of the HPM to quantify seat measurements 3. Cross sectional seat trim outlines For convenience and simplicity, many terms associated with H-point devices use human body parts in their name.
Touch Interactive Display Systems: Human Factors Considerations, System Design and Performance Guidelines
This ARP covers the system design, human interface considerations, and hardware performance recommendations and requirements for touch interactive electronic display systems installed in the cockpit/flight deck for use by pilots. System design and human interface considerations include: identification of functions that could use and benefit from touch interactions, the pilot and cockpit/flight deck environment characteristics that impact usability, and specific pilot interface characteristics such as touch mode, single and multi touch applications, feedback, latency, potential human error, and basic usability. Also addressed are workload, fatigue, and transition from hard to soft control considerations. Hardware issues cover performance aspects of touch screens installed on cockpit/flight deck displays. This ARP is intended to cover Part 23 and 25 category airplanes as well as Part 27 and 29 rotorcraft.
Comfort is a main factor in customer's decision when buying a car. The seat plays a very important role, as it is the interface between occupant and vehicle. Pressure distribution is today's most common approach to characterize seat comfort, but it shows limitations. Analysis of human inter-tissue stress tends to be relevant for an objective comfort assessment. This paper presents the construction and validation of a CAE human model, based on Magnetic Resonance Imaging scans and in-vivo tests data. Correlation between objective criteria and subjective evaluation will be investigated, comfort performance of a real seat will be predicted.
Estimation of Body Mass Index Effect on Lower Extremity Injuries for Lateral Collision With-out Airbag
Abstract A comprehensive analysis was performed to evaluate the effect of BMI on different body region injuries for side impact. The accident data for this study was taken from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). It was found that the mean BMI values for driver and front passengers increases over the years in the US. To study the effect of BMI, the range was divided into three groups: Thin (BMI<21), Normal (BMI 24-27) and Obese (BMI>30). Other important variables considered for this study were model year (MY1995-99 for old vehicles & MY2000-08 for newer vehicles), impact location (side-front F, side-center P & side-distributed Y) and direction of force (8-10 o'clock for nearside & 2-4 o'clock for far-side). Accident cases involving older occupants above 60 years was omitted in order to minimize the bone strength depreciation effect. Results of the present study indicated that the Model Year has influence on lower extremity injuries.