ERGONOMICS OPTIMIZATION TOOL

The workplace ergonomics optimization support tool aims to simulate a worker in its workplace to point to possible issues that the specific worker might run into, and to suggest the best workplace configuration for the worker.  This tool simulates the workplace as the worker would work in it with the specific data of the worker’s characteristic, to find improvements for the workplace and mark some worker-workplace combinations as incompatible, at least until the detected problems are resolved. To bypass the necessity for a human-in-the-loop ergonomics optimization that require a complicated setup (e.g. with the use of IMUs) and allow to perform only limited tests, we developed a system that evaluates the design of a workspace by performing physics-based simulations entirely in virtual reality (VR). For this purpose, a digital human model (DHM), acting as a digital twin of the worker, interacts with the virtual environment and motion data are extracted and mapped to a bio-physical model equipped with all parameters necessary to solve the physics equations. Inverse kinematics is subsequently performed using the markers’ location to assist posture estimation, followed by inverse dynamics for the calculation of torques and forces. The alternative postures and motion scenarios can be used for human-centered product design. Upon ergonomic analysis and parameter optimization, the obtained virtual design can be validated by means of immersive reality technologies applied in an identical way to the physical world.

To do this, multiple inputs are needed. From the worker model the worker characteristics are extracted, which include all of the necessary worker measurements, as well as the preexisting conditions. The list of worker measurements are:

  • Foot length and height
  • Lower leg length
  • Higher leg length
  • Torso length
  • Shoulder width
  • Upper arm length
  • Lower arm length
  • Hand length
  • Neck length
  • Head height

Other of the inputs required for this tool is the workplace model which describes the workplace and how the worker interacts with it.

We present an application example of ergonomics assessment in the interior of a car to simulate the workspace of the truck drivers of the ANEFA pilot in the respective video. The simulation involves interaction with the instrument panel. The corresponding instances of the heat map, that illustrate the energy distribution for different upper body joints during a “reach-out” movement of the driver within the vehicle cabin, are shown. These results provide a useful insight about the location of the car seat, which could be placed in a more ergonomic position, that provides comfort and applies less accumulated load to the driver.