Hum Factors

ObjectiveThe study objectives were to identify factors affecting extension ladders\ue2\u20ac\u2122 angular positioning and evaluate the effectiveness of two anthropometric positioning methods.BackgroundA leading cause for extension ladder fall incidents is a slide-out event, usually related to suboptimal ladder inclination. An improved ladder positioning method or procedure could reduce the risk of ladder stability failure and the related fall injury.MethodParticipants in the study were 20 experienced and 20 inexperienced ladder users. A series of ladder positioning tests was performed in a laboratory environment with 4.88-m (16-ft) and 7.32-m (24-ft) ladders in extended and retracted positions. The setup methods included a no-instruction condition and two anthropometric approaches: the American National Standards Institute A14 and \ue2\u20ac\u153fireman\ue2\u20ac? methods. Performance measures included positioning angle and time.ResultsThe results indicated that ladder setup method and ladder effective length, defined by size and extended state, affected ladder positioning angle. On average, both anthropometric methods were effective in improving extension ladder positioning; however, they required 50% more time than did the no-instruction condition and had a 9.5% probability of setting the ladder at a less-than-70\uc2\ub0 angle. Shorter ladders were consistently positioned at shallower angles.ConclusionAnthropometric methods may lead to safer ladder positioning than does no instruction when accurately and correctly performed. Workers tended to underperform as compared with their theoretical anthropometric estimates. Specific training or use of an assistive device may be needed to improve ladder users\ue2\u20ac\u2122 performance.ApplicationThe results provide practical insights for employers and workers to correctly set up extension ladders.CC999999/Intramural CDC HHS/United States2015-12-15T00:00:00Z22768637PMC467918

Appl Ergon

A leading cause for extension ladder fall incidents is a slide-out event usually related to suboptimal ladder inclination. An improved ladder positioning method or procedure could reduce the risk of ladder stability failure and the related fall injury. The objective of the study was to comparatively evaluate the effectiveness of a multimodal angle indicator with other existing methods for extension ladder angular positioning. Twenty experienced and 20 inexperienced ladder users participated in the study. Four ladder positioning methods were tested in a controlled laboratory environment with 4.88 m (16 ft) and 7.32 m (24 ft) ladders in extended and retracted positions. The positioning methods included a no-instruction method, the current standard anthropometric method, and two instrumental methods - a bubble level indicator, and a multimodal indicator providing direct feedback with visual and sound signals. Performance measures included positioning angle and time. The results indicated that the anthropometric method was effective in improving the extension ladder positioning angle (p < 0.001); however, it was associated with considerable variability and required 50% more time than no-instruction. The bubble level indicator was an accurate positioning method (with very low variability), but required more than double the time of the no-instruction method (p < 0.001). The multimodal indicator improved the ladder angle setting as compared to the no-instruction and anthropometry methods (p < 0.001) and required the least time for ladder positioning among the tested methods (p < 0.001). An indicator with direct multimodal feedback is a viable approach for quick and accurate ladder positioning. The main advantage of the new multimodal method is that it provides continuous feedback on the angle of the device and hence does not require repositioning of the ladder. Furthermore, this indicator can be a valuable tool for training ladder users to correctly apply the current ANSI A14 standard anthropometric method in ladder angular positioning. The multimodal indicator concept has been further developed to become a hand-held tool in the form of a smart phone application.CC999999/Intramural CDC HHS/United States2015-12-16T00:00:00Z23177178PMC468126

Design of an autonomous Lunar construction utility vehicle

In order to prepare a site for a manned lunar base, an autonomously operated construction vehicle is necessary. A Lunar Construction Utility Vehicle (LCUV), which utilizes interchangeable construction implements, was designed conceptually. Some elements of the machine were studied in greater detail. Design of an elastic loop track system has advanced to the testing stage. A standard coupling device was designed to insure a proper connection between the different construction tools and the LCUV. Autonomous control of the track drive motors was simulated successfully through the use of a joystick and computer interface. A study of hydrogen-oxygen fuel cells has produced estimates of reactant and product size requirements and identified multi-layer insulation techniques. Research on a 100 kW heat rejection system has determined that it is necessary to house a radiator panel on a utility trailer. The impact of a 720 hr use cycle has produced a very large logistical support lien which requires further study

NIOSH science awards 2014

The annual NIOSH Science Awards are an opportunity for NIOSH to honor researchers for excellence in science. The awards include the following:\u2022 The Alice Hamilton Award, for scientific excellence of technical and instructional materials by NIOSH scientists and engineers.\u2022 The James P. Keogh Award, for outstanding service by an individual in the occupational safety and health field.\u2022 The Bullard-Sherwood Research-to-Practice Award, for exceptional efforts by NIOSH researchers and partners in applying occupational safety and health research to the prevention of workplace fatalities, illnesses, or injuries.\u2022 The Director\u2019s Award for Extraordinary Intramural Science.NIOSH Presents 2014 Awards for Significant Scientific Contributions -- Alice Hamilton Awards for Occupational Safety and Health -- Bullard-Sherwood Research-to-Practice (r2p) Award -- Director\u2019s Intramural Award for Extraordinary Science (DIA) -- James P. Keogh Award for Outstanding Service in Occupational Safety and Health -- NIOSH Nominations for the Charles C. Shepard Science Award Nominations.201

Topics in construction safety and health : falls : an interdisciplinary annotated bibliography

"These referenced articles provide literature on falls by construction workers and their risks on the job." - NIOSHTIC-2NIOSHTIC no. 20068247Production of this document was supported by cooperative agreement OH 009762 from the National Institute for Occupational Safety and Health (NIOSH). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.Falls-annotated-bibliography.pdfcooperative agreement OH 009762 from the National Institute for Occupational Safety and Healt

Topics in construction safety and health : training : an interdisciplinary annotated bibliography

"These referenced articles provide literature about the need for training and safety education in the construction industry to decrease and prevent the number of worker injuries and fatalities in this field." - NIOSHTIC-2NIOSHTIC no. 20068259Production of this document was supported by cooperative agreement OH 009762 from the National Institute for Occupational Safety and Health (NIOSH). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.Training-annotated-bibliography.pdfcooperative agreement OH 009762 from the National Institute for Occupational Safety and Healt

Design and Validation of a Device to Aid in Extension Ladder Setup

The problem of ladder base slippage is a leading cause of workplace injuries and causes a number of annual deaths.  Research has shown that ladder users tend to set up extension ladders at an angle between 66° and 69° above horizontal, which is much shallower than the specified standard of 75.5°. This results in an increase in the friction required at the base of the ladder to support the weight of the ladder and its user, and leads to an increased likelood of a slideout accident.  To counteract the problem of ladder base slipping, a device was developed to aid the user in achieving a proper setup angle.  The device uses a mechanical switch to wired to LEDs that provide the user feedback on setup angle.  The device was tested in a laboratory environment, and was shown to positively impact the ability of the user to erect the ladder at a proper angle

Human engineering design criteria study Final report

Human engineering design criteria for use in designing earth launch vehicle systems and equipmen

A quasi-static model-based control methodology for articulated mechanical systems

Hazardous environments encountered in nuclear clean-up tasks mandate the use of complex robotic systems in many situations. The operation of these systems is now performed primarily under teleoperation. This is, at best, five times slower than equivalent direct human contact operations.One way to increase remote work efficiency is to use automation for specific tasks. However, the unstructured, complex nature of the environment along with the inherent structural flexibility of mobile robot work systems makes task automation difficult and in meiny cases impossible.This research considers a quasi-static macroscopic modeling methodology that could be combined with sensor-guided manipulation schemes to achieve the needed operational accuracies for remote work task automation. Application of this methodology begins with an off-line analysis phase in which the system is identified in terms of the ideal D-H parameters and its structural elements. Themanipulator is modeled with fundamental components (i.e. beam elements, hydraulic elements, etc)and then analyzed to determine load dependent functions that predict deflections at each joint and the end of each link. Next, forces applied at the end-effector and gravity loads are projected into local link coordinates using the undeflected pose of the manipulator. These local loads are then used to calculate deflections which are expressed as 4 by 4 homogeneous transformations and inserted into the original manipulator transformations to predict end-effector position and orientation (anderror/deflection vector). The error/deflection vector is then used to determine corrective actions based on the manipulator flexibilities, pose and loading. This corrective action alters the manipulator commands such that the manipulator end-effector is moved to the desired location based on the error between the model predictions and commanded position using the ideal kinematics.The modeling methodology can readily be applied to any kinematic chain. This allows analysis of a conceptual system in terms of basic mechanics and structural deflections. The methodology allows components such as actuators or links to be interchanged in simulation so that alternative designs may be tested. This capability could help avoid potentially costly conceptual design flaws at a very early stage in the design process.Real-time compensation strategies have been developed so as to lessen concerns with structural deformation during use. The compensation strategies presented here show that the modeling methods can be used to increase the end-effector accuracy by calculating the deflections and command adjustments iteratively in real-time. The iterations show rapid convergence of the adjusted command positions to reach the desired end-effector location. The compensation methods discussed are easily altered to fit systems of any complexity, only requiring changes in the number of variables and the number of equations to solve. Most importantly, however, is that the modeling methodology,in conjunction with the compensation methods, can be used to correct for a significant fraction of the errors associated with manipulator flexibility effects. Implementation in a real-time system only involves changes in path planning, not in low-level control.The modeling methods and deflection predictions were verified using a sub-system of the OakRidge National Laboratory\u27s Dual Arm Work Platform. The experimental method used simple,non-contact measurement devices that are minimally intrusive to the manipulator\u27s workspace. The Results show good correlation between model and experimental results for some configurations. Experimental results can be extrapolated to predict that errors could be reduced from several inches to several tenths of an inch for systems like the Dual Arm Work Platform in some configurations.Continuing work will investigate applications to selective automation for Decontamination and Dismantlement tasks, using this work as a necessary foundation