Simultaneous stabilizing feedback control of linear and angular momentum in human walking.

Area of Science:

• Biomechanics
• Human locomotion
• Robotics

Background:

• Stabilizing bipedal gait is mechanically complex.
• Previous research focused on controlling the body's center of mass (CoM).
• Existing models often linked CoM linear momentum deviations to center of pressure (CoP) shifts, but this overlooks angular momentum dynamics.

Purpose of the Study:

• To investigate the simultaneous control of linear and angular momentum in human walking.
• To test the hypothesis that correlations between CoP-CoM distance and ground reaction forces are linked to controlling both linear and angular momentum.
• To re-evaluate previous findings on gait stabilization in light of dual momentum control.

Main Methods:

• Analysis of linear and angular momentum during human walking.
• Combining linear and rotational motion equations for a linked rigid segment system.
• Fitting regression models to experimental data from participants walking at normal and slow speeds.

Main Results:

• Linear and angular momentum in human walking exhibit quasi-periodic functions with similar periodicity and phase.
• The horizontal distance between CoP and CoM is correlated with horizontal force, as predicted by combined motion equations.
• Ground reaction forces and moments could be predicted from preceding linear and angular momentum deviations.

Conclusions:

• Human walking simultaneously controls both linear and angular momentum.
• This dual control mechanism explains observed correlations between CoM states and CoP/foot locations in prior studies.
• The findings provide a more comprehensive mechanical understanding of gait stabilization.