Predicting ground reaction forces of human gait using a simple bipedal spring-mass model

Area of Science:

• Aerospace Engineering
• Biomechanics
• Human Factors in Aviation

Background:

• Aircraft design prioritizes lightweight and cost-efficiency under certification requirements.
• Human-induced loads from occupant gait are critical for optimal aircraft interior design but challenging to estimate.
• Accurate prediction of these loads is essential for ensuring structural integrity and passenger safety.

Purpose of the Study:

• To develop and validate a simplified bipedal spring-mass model for predicting human-induced loads during gait in aircraft.
• To integrate this predictive model into an end-to-end aircraft design process, minimizing the need for additional experimental data.
• To compare the model's predictions with experimental data and statistical regression models for enhanced accuracy.

Main Methods:

• A bipedal spring-mass model with roller feet was employed to simulate human gait and ground reaction forces (GRF).
• The model utilized easily estimable input variables (gait speed, body mass, body height) and two parameter constraints for simulation.
• Experiments involving 12 test persons walking in an aircraft mock-up were conducted for model calibration and validation, supplemented by statistical regression models.

Main Results:

• The bipedal model, using gait speed as a constraint, achieved good estimates of force maxima with a 5.3% error.
• Using initial GRF as a constraint provided more reliable predictions.
• Both constraints accurately predicted contact time with a 0.9% error, and the full GRF curve predictions were comparable to reference models.

Conclusions:

• The developed bipedal model offers a reliable and efficient method for predicting human-induced loads in aircraft design.
• The model's ability to predict loads without extensive experimental data supports its integration into early-stage aircraft design processes.
• This approach contributes to more optimized, lightweight, and cost-efficient aircraft designs while maintaining safety standards.