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Sound Ergonomics is an important attribute and differentiator among trucks, because professional truck drivers spend many hours of their work time on the road driving. Ergonomics affects areas of driver safety, comfort, accommodation and performance. The purpose of this paper is to showcase the ergonomic principles, tools and process that were applied throughout the development cycle of Freightliner's new Medium Duty Truck: Business Class M2. An important centerpiece of the ergonomic process at Freightliner is RAMSIS, a 3-D Digital Human Modeling software. It allows effective evaluation of ergonomic issues in the CAD environment early on in the development cycle, thus reducing the risk of expensive re-designs at later stages in the vehicle development process. Several examples with RAMSIS will highlight the benefits of applying 3-D human modeling to the design process.

The purpose of this paper is to showcase the industrial design and ergonomic principles, tools and the processes that were concurrently applied throughout the development cycle of Thom”. Thomas Built Buses Engineering and Freightliner LLC Engineering groups worked interactively to optimize driver and passenger ergonomics, comfort and safety. Several examples are shown to highlight the benefits of applying 3-D human modeling to the design process. Resulting improvements of visibility, accommodation, and safety are shown.

Understanding external vehicle aerodynamics is an integral step in reducing overall vehicle fuel consumption. This is particularly true for long-haul commercial vehicles where an incremental decrease in drag can translate into significant fuel savings based on the number of miles traveled over the course of a truck's working life. The ability to critically analyze the air motion adjacent to commercial vehicles is a step toward understanding the overall affects of external aerodynamics on the entire vehicle. To achieve this understanding, the aerodynamics problem must be divided into manageable tasks that can each yield qualitative and quantitative results. A two-dimensional (2D) External Aerodynamics Tool (EAT) has been developed that enables computational fluid dynamics (CFD) simulations of commercial vehicles to be performed quickly and easily.

This paper describes the ergonomics program at Freightliner and how it is integrated in the engineering and design process. It will also describe how we use advanced technologies such as 3-D Digital Human Modeling with RAMSIS and how these are applied to the design process to ensure optimized ergonomics in our trucks.

A Rapid Duct Development and Diagnostic airflow simulation Tool (R3DT) has been developed that allows computational fluid dynamics (CFD) airflow simulations to be performed on complex three-dimensional (3D) Heating, Ventilation and Air Conditioning (HVAC) ducts quickly, easily and cost effectively. R3DT is a very automated approach to performing grid generation and CFD. It draws upon the strengths of the tools of ICEM CFD Engineering to create a fully tetrahedral mesh for complicated air duct geometries based on the original CAD data. It also uses FLUENT™ as the tetrahedral CFD solver. R3DT enables designers to make informed design decisions based on the predicted performance of their duct designs early in the development process, with the data still in CAD format. The concepts behind R3DT, as well as its application to a series of three-dimensional ducts with varying levels of geometrical complexity will be presented.

This paper describes application examples of RAMSIS, a 3-D CAD human model for ergonomic truck evaluations, to truck design. RAMSIS realistically simulates truck driver postures and locations, an important prerequisite to having confidence in subsequent ergonomic analyses. We show examples of how visibility evaluations compare to traditional SAE methods, arm reach and force evaluation; and an example for entry/exit evaluations.

This paper describes the validation of RAMSIS, a 3-D CAD human model for ergonomic vehicle evaluation at General Motors (GM). The model’s capability to correctly predict position and posture in vehicle CAD environments was tested. H- and Eye point locations between RAMSIS manikins and their human counterparts were compared. We concluded that RAMSIS has good position and posture prediction capabilities and is a useful CAD ergonomic evaluation and design tool for vehicle interiors.

This paper describes the validation of RAMSIS, a 3-D CAD human model for ergonomic vehicle evaluation. At GM NAO, the model’s capability to correctly predict position and posture in vehicle CAD environments was tested. H- and Eye point locations between RAMSIS manikins and their human counterparts were compared. At GM/SAAB the model’s postural discomfort predictability was evaluated. Changes in postural discomfort predictions of the RAMSIS manikins were compared to that of the human subjects when they evaluated two different driving buck conditions. We concluded that RAMSIS has good position, posture and postural discomfort prediction capabilities and is a useful CAD ergonomic evaluation and design tool for vehicle interiors.