Anthropometric criteria for the design of tractor cabs and protection frames

Abstract

Improved human-tractor interface designs, such as well-accommodated operator enclosures (i.e. cabs and protection frames) can enhance operator productivity, comfort and safety. This study investigated farm-worker anthropometry and determined the critical anthropometric measures and 3-D feature envelopes of body landmarks for the design of tractor operator enclosures. One hundred agriculture workers participated in the study. Their body size and shape information was registered, using a 3-D full-body laser scanner. Knee height (sitting) and another eight parameters were found to affect the cab-enclosure accommodation rating and multiple anthropometric dimensions interactively affected the steering wheel and gear-handle impediment. A principal component analysis has identified 15 representative human body models for digitally assessing tractor-cab accommodation. A set of centroid coordinates of 34 body landmarks and the 95% confidence semi-axis-length for each landmark location were developed to guide tractor designers in their placement of tractor control components in order to best accommodate the user population. Finally, the vertical clearance (90 cm) for agriculture tractor enclosure in the current SAE International J2194 standard appeared to be too short as compared to the 99th percentile sitting height of male farm workers in this study (100.6 cm) and in the 1994 National Health and Nutrition Examination Survey III database (99.9 cm) and of the male civilian population in the 2002 Civilian American and European Surface Anthropometric Resource database (100.4 cm).

Anthropometric Procedures for Protective Equipment Sizing and Design

“…A 95% accommodation level was then selected as this threshold was found to sufficiently balance cab efficiency and cost-effectiveness. This approach resolved the problem of the univariate approach for multiple measurements by taking into account both the overall body size variance and body segment proportional variability (Hsiao et al, 2005;Zehner, Meindl, & Hudson, 1993). The models generated in this study therefore include not only overall large and small persons but also individuals of different body configurations.…”

“…The intent was to remove known noisy variables and to reduce data sets to a more manageable size while better addressing equipment accommodation (Bittner, Glenn, Harris, Iavecchia, & Wherry, 1987;Meindl, Zehner, & Hudson, 1993). Principal component analysis (PCA) has been the premier method of variable reduction and has been effective in increasing body size accommodation in tractor cab and cockpit designs (Hsiao et al, 2005;Robinson, Robinette, & Zehner, 1992); it however was found lacking when applied to body dimensions, which showed poor intercorrelation, such as facial dimensions (Hudson, Zehner, & Meindl, 1998).…”

“…Based on the six-step paradigm for anthropometric product development, the essential dimensions for this study are stature, weight, sitting height, acromial height, elbow rest height, elbow-wrist length, knee height, buttock-knee length, acromion-grip length, hip breadth, and bideltoid breadth, as per cab design needs (Hsiao et al, 2005). The population to be considered is firefighters and the percentage of the population to be accommodated is 95% of firefighters.…”

Ergonomic Design: Experimental Studies of Multi-Task Vehicle

“…They checked the location of controls against anthropometrical data. Other example is the research of [16] that found that the SAE 1994 standard for tractors, does not meet anthropometric requirements for manual hand reach. Other studies, such as the study of [24], checked the best location of the pedals in a tractor, in relation to the human strength needed for their operation.…”

Applications of DHM in Agricultural Engineering: A Review

“…Traditional ergonomics evaluation process involve full-size physical mock-up, selection of a representative sample of potential users for executing a series of appropriate human factors evaluations and it is also time consuming, reactive, incomplete, sporadic, and in many cases difficult, too [3]. Although it is well understood that use of scientific and technological advancements will improve the quality as well as productivity with less time and cost but the use of traditional approach of ergonomic evaluation is still in practice for improvement of existing designs of farm tools and implements [4][5][6][7][8][9] Need of virtual ergonomics evaluation techniques in agriculture: Virtual designing and evaluation technology is now widely accepted as a major breakthrough in scientific and technological advancement which leads new possibilities to solve intricate problems, not only in engineering but also in other applied areas including agricultural sector. Need for implementation of virtual ergonomics evaluation technology in agriculture can be perceived by recognizing the problems associated with traditional methods for design, development and ergonomic evaluation.…”