simMACT, a Software Demonstrator to Improve Maximum Actuation Joint Torques Simulation for Ergonomics Assessment

Area of Science:

• Biomechanics
• Ergonomics
• Human Factors Engineering

Background:

• Workplace biomechanical risk assessment relies on accurate maximum joint torque data.
• Current digital human model (DHM) software offers imprecise estimates, neglecting static postures and inter-joint couplings.
• Existing DHM tools often depend on limited torque databases, hindering comprehensive analysis.

Purpose of the Study:

• To present a novel methodology for assessing maximum actuation joint torques using zonotopes and musculoskeletal simulation.
• To overcome the limitations of existing DHM software in estimating joint torques for dynamic postures and complex musculoskeletal interactions.
• To provide designers with more reliable data for workplace design and risk assessment.

Main Methods:

• Developed a methodology employing zonotopes (a class of polytopes) and musculoskeletal simulation.
• Enabled estimation of maximum joint torques for any given posture.
• Incorporated specificities of the human musculoskeletal system, including inter-joint couplings.

Main Results:

• The methodology successfully estimated maximum joint torques, considering dynamic postures and musculoskeletal specifics.
• A case study comparing simulated torques for an upper limb isometric task showed errors comparable to or smaller than existing DHM tools.
• The simulation results demonstrated the potential for improved interpretation of inter-joint couplings.

Conclusions:

• The proposed methodology offers a more comprehensive and reliable approach to assessing maximum actuation joint torques compared to current DHM software.
• This method can enhance the understanding of inter-joint couplings and inform the selection of mathematical models and experimental designs.
• Implementation in DHM software could significantly improve workplace design and biomechanical risk assessment.