Inverse dynamics of mechanical multibody systems: An improved algorithm that ensures consistency between kinematics
Herre Faber1,2, Arthur J van Soest1, Dinant A Kistemaker1
1Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands.
Plos One
|September 29, 2018
Summary
This study introduces a new optimization algorithm for inverse dynamics, ensuring mechanical consistency between forces and kinematics. The method eliminates unrealistic residual forces and torques, improving the accuracy of joint torque calculations.
Area of Science:
- Biomechanics
- Kinetics
- Human Movement Analysis
Background:
- Inverse dynamics calculates joint torques using kinematics and forces.
- Inconsistencies between measured kinematics and forces lead to residual errors.
- Residual forces and torques are artifacts, not real physical quantities.
Purpose of the Study:
- To develop a constrained optimization algorithm for mechanically consistent inverse dynamics.
- To eliminate residual forces and torques in rigid body models.
- To improve the validity of calculated net joint torques and power.
Main Methods:
- A constrained optimization algorithm was developed.
- The algorithm finds kinematics consistent with measured external forces.
- It minimizes deviations from measured kinematics.
- Tested on human walking data at various speeds.
Main Results:
- The algorithm converged to a solution with zero residual forces and torques.
- Ground reaction forces remained unchanged.
- Minor alterations were observed in measured kinematics.
- Demonstrated improved consistency between kinematics and forces.
Conclusions:
- The proposed algorithm ensures a mechanically consistent description of forces and kinematics.
- This enhances the validity of inverse dynamics calculations.
- It provides a more accurate representation of joint torques and power in biomechanical analysis.
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