Simulating Force-Posture Co-evolution in Horizontal Pushing Task using a Digital Human Model

Abstract

Ergonomic analysis of a manual material handling task is essential to evaluate the musculoskeletal disorder risk involved. Digital Human Model (DHM) simulation is one of the techniques used to identify potential hazards. In the current method, the user provides force and posture, and subsequently, the simulation computes the joint stresses. In most simulations, the force and the posture are independent; therefore, they are mutually irresponsive. The work presented here argues that the responsive co-evolution of force and posture is essential for realistic performance assessment. It is known that musculoskeletal loading is affected by the force direction. Therefore, a wrong estimation of applied force direction could lead to an inaccurate assessment of joint stresses. In this work, first, we performed experiments to identify the unknown variables influencing the applied direction of force. Subsequently, based on the obtained data, a mathematical force model is developed that correlates the applied direction of the force with the position of the point of application of force and magnitude. The force model is then integrated into an existing DHM; this removes the need to provide the force direction manually. Using a physics-based object response model for a linear spring and box on a table experiencing static and dynamic friction, two illustrative task simulations that do not require any force specification are presented. The necessary exertions and associated biomechanical efforts can be derived from the result.

Keywords: Simulation Study, Posture Prediction, Digital Human Biomechanics, Force And Posture

DOI: 10.54941/ahfe1007700