Simulation of maximum isometric and isokinetic elbow actuation torques based on zonotopes

How can work equipment designers estimate the maximum joint actuation torques that operators can perform at the workstation? These data are essential for ergonomic risk assessment, yet designers usually only have at their disposal the databases provided with digital mannequin software. This paper describes a methodology based on polytopes and musculoskeletal simulation to assess maximum actuation torques for any task and posture. As a partial validation process, this study also compares such simulated maximum actuation torques to experimental data described in the literature focusing on maximum isometric and isokinetic actuation torques of the elbow.
Simulated and experimental torques show similar trends. This may be a significative benefit of this approach over DHM data that completely neglects the influence of joint velocities on actuation capabilities. However, the parameterisation of the musculoskeletal model used by this approach is to be explored further to reduce the gap observed between experiments and simulation. If this step is completed, this approach may provide a convenient way to provide work equipment designers with more accurate and comprehensive estimations of maximum actuation performances of operators at the workplace than those at their disposal through current Digital Human Model software tools.