Exploring the Design Space Using a Surrogate Model Approach With Digital Human Modeling Simulations

Author(s):  
Salman Ahmed ◽  
Mihir Sunil Gawand ◽  
Lukman Irshad ◽  
H. Onan Demirel

Computational human factors tools are often not fully-integrated during the early phases of product design. Often, conventional ergonomic practices require physical prototypes and human subjects which are costly in terms of finances and time. Ergonomics evaluations executed on physical prototypes has the limitations of increasing the overall rework as more iterations are required to incorporate design changes related to human factors that are found later in the design stage, which affects the overall cost of product development. This paper proposes a design methodology based on Digital Human Modeling (DHM) approach to inform designers about the ergonomics adequacies of products during early stages of design process. This proactive ergonomics approach has the potential to allow designers to identify significant design variables that affect the human performance before full-scale prototypes are built. The design method utilizes a surrogate model that represents human product interaction. Optimizing the surrogate model provides design concepts to optimize human performance. The efficacy of the proposed design method is demonstrated by a cockpit design study.

Author(s):  
Aitor Iriondo Pascual ◽  
Dan Högberg ◽  
Anna Syberfeldt ◽  
Erik Brolin ◽  
Lars Hanson

Simulation software is used in the production development process to simulate production and predict behaviors, calculate times, and plan production in advance. Digital human modeling (DHM) software is used to simulate humans working in production and assess whether workstation designs offer appropriate ergonomic conditions for the workers. However, these human simulations are usually carried out by human factors engineers or ergonomists, whereas the production simulations are carried out by production engineers. Lack of integration of these two simulations can lead to suboptimal solutions when the factory is not optimized to improve both productivity and ergonomics. To tackle this problem, a platform has been developed that connects production flow simulation software data and DHM software data and integrates them in a generic software for data treatment and visualization. Production flow simulation software data and DHM software data are organized in a hierarchical structure that allows synchronization between the production data and the ergonomic data on the target simulation software. The platform is generic and can be connected to any production flow simulation software and any DHM software by creating specific links for each software. The platform requires only the models of the production line, workstations, and tasks in order to perform the simulations in the target simulation software and collect the simulation results to present the results to the user of the platform.


2008 ◽  
Vol 4 (1) ◽  
pp. 41-74 ◽  
Author(s):  
Don B. Chaffin

Digital human modeling (DHM) technology offers human factors/ergonomics specialists the promise of an efficient means to simulate a large variety of ergonomics issues early in the design of products and manufacturing workstations. It rests on the premise that most products and manufacturing work settings are specified and designed by using sophisticated computer-aided design (CAD) systems. By integrating a computer-rendered avatar (or hominoid) and the CAD-rendered graphics of a prospective workspace, one can simulate issues regarding who can fit, reach, see, manipulate, and so on. In this chapter, I briefly describe the development of various DHM methods to improve CAD systems. Past concerns about early DHM methods are discussed, followed by a description of some of the recent major developments that represent attempts by various groups to address the early concerns. In this latter context, methods are described for using anthropometric databases to ensure that population shape and size are well modeled. Efforts to integrate various biomechanical models into DHM systems also are described, followed by a section that outlines how human motions are being modeled in different DHM systems. In a final section, I discuss recent work to merge cognitive models of human performance with DHM models of manual tasks. Much has been accomplished in recent years to make digital human models more useful and effective in resolving ergonomics issues during the design of products and manufacturing processes, but much remains to be learned and applied in this rapidly evolving aspect of ergonomics.


Author(s):  
Zunling Du ◽  
Yimin Zhang

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.


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