Susan M. Evans

On the validity of an isometric biomechanical model of worker strengths

Abstract Over the last 18 years the Center for Ergonomics at The University of Michigan has worked to develop a computerized, biomechanically based model to predict worker muscle strengths in various tasks. During the last few years new input strength data has been acquired from published works of others. Worker isometric strength testing also has been performed by the Center in various industries to determine gross lifting, pushing and pulling capabilities of a heterogeneous group of men and women. These data, acquired from 1577 men and women are compared to the strength predictions of the biomechanically based model. For prediction of mean strength capabilities of both men and women performing varied types of symmetric sagittal plane exertions, the model results were relatively unbiased and were well correlated with r 2 between 0.85 and 0.88 with the population data. The results were not as good for predicting the mean strengths of two-handed assymetric exertions (r 2 between 0.54 and 0.74), and for one...

Computerized Biomechanical Models in Manual Work Design

This paper reviews the development and use. of various anthropometric and biomechanical models that have become available as programs operating in different computing environments. Some of the models to be presented are meant to assist in the design of a workstation when visual and physical reach requirements are high (e.g., COMBIMAN, SAMMIE and TEMPUS/BUBBLEPERSON). Other models are meant to analyze and assist in the design of tasks requiring significant physical effort (e.g., UM 2D and 3D Strength Models). Limitations and future needs will be discussed.

Organizational and Process Differences Influencing Ergonomic Design

A study of current design practices was conducted to identify organizational and design process differences influencing the use of ergonomic information in manual workspace design. Significant differences regarding the design information sources and objectives existed between preliminary, or division-level, and detailed, or plant-level, design activities. Ergonomic concerns, e.g., health and safety factors and operator feedback, were most clearly present in plant-level design; unfortunately, plant designers also had the least flexibility, in terms of design parameters to vary, and dollars to spend, to retrofit inadequate designs. Results indicate specific factors, (such as designer temporal and geographic proximity to the design implementation), to consider during the development of an effective industrial ergonomics training program.

Some Computational Problems in Developing Computerized Man-Models

Anthropometric data may be presented in a variety of forms, with probably the most common being tabular format. This includes percentile and summary statistical listings and regression equations. This form provides quick, easy reference but unfortunately this is not always the most useful presentation for solving three-dimensional design problems. Design problems need anthropometric data presented in the context of human-form models, incorporating human movement as well as static anthropometry. This type of design requirement by the United States Air Force led to the development of the 3-D COMBIMAN (COMputerized BIomechanical MAN-model) model.

Ergonomics@Ford.Com: Using the Intranet to Enhance Program Effectiveness

Ford Motor Companys Automated Evidence Book, known as ErgoRx, is a Web-browser-based application that permits plant-level Local Ergonomics Committees (LECs) to manage the process for identifying, tracking, resolving and sharing ergonomic concerns with reduced administrative burden. The Intranet application also allows Corporate and Division ergonomics personnel to view LEC concern data remotely and obtain measures of program effectiveness directly.

The Edge System: Ergonomic Design Using Graphic Evaluation

EDGE is a computer-based ergonomic workspace design system which integrates several models of operator performance with a common graphic interface. In addition to serving as a practical design system, it also serves as a research tool for understanding the ergonomic design process in industry. System users include trained ergonomists and engineers responsible for manual workspace design. The design system centers around a core vocabulary of task-related terms. A common input format, modeled after the traditional “work methods table” addresses the input requirements of the varied human performance models. Output from the performance models is displayed on multiple screens in varying levels of detail. Among the measures of physical stress currently integrated into the system are models of biomechanical strength, NIOSH lifting limits, metabolic energy expenditure, and elemental time prediction.

The Use of Ergonomic Concerns Data as a Proactive Input to the Design of Workplace Tools

The Ford Motor Company has recorded over 5606 ergonomic concerns relating to job hazards through their automated evidence book ErgoRx. As part of a review of the ergonomics process in Ford, a study was carried out to look at the transfer of ergonomic information between division process engineers and plant ergonomics personnel. The study focused on ergonomics training and background knowledge, and Ford tools used to provide ergonomics information and the feedback processes. Issues on the effective feedback of ergonomics data early on in the design process are of particular interest in the light of the recent repeal of the OSHA Ergonomics regulation. Instead of using reportable ergonomics concerns to trigger remedial actions, concerns can be reduced by designing-out the features that cause the problems. Used in this way concerns data, as well as existing ergonomics tools, can be used as a cost effective, proactive input in new and redesign activities. This approach, used more widely, could be an effective way of removing objections to the imposition of a difficult to apply, and largely reactive ergonomics regulation.

Ergonomics in Workspace Design: Current Practices and an Alternative Computer-Aided Approach

A research project was conducted to identify current industrial workspace design practices, especially regarding the consideration paid to the human operator in manual workspaces, and to develop an approach for presenting ergonomic information to designers in formats conducive to the design process. Specific operator physical-stress-related performance factors considered in this research include strength capabilities, reach feasibility, and movement times. The paper presents selected results of a survey of 40 engineers/designers, and outlines the criteria for a computer-aided ergonomic design system for manual workspace design.

Office Automation and Managerial Productivity: Some Issues

Efforts to streamline office processes have, in the past, concentrated on augmenting clerical tasks through automated word processing and document preparation technologies. More recently, the needs for improved office productivity have directed productivity boosting technologies at managers and their jobs. This paper presents concepts of managerial productivity within the framework of evolving managerial roles in the changing office environment. Areas where office technologies could augment managerial activities and several socioeconomic considerations for the implementation of new technologies are also discussed.