An Optimal Control-Based Digital Computational Framework for Predicting the Entire Cycle Sit-to-Stand Motion in...

Area of Science:

• Biomechanics
• Robotics
• Rehabilitation Engineering

Background:

• Sit-to-stand movement is crucial for lower limb amputees' independence.
• Existing models lack focus on transtibial amputees and buttocks-seat contact.

Purpose of the Study:

• Develop an optimal control framework for predicting transtibial amputee sit-to-stand motion.
• Analyze the biomechanical impact of varying prosthesis stiffness.

Main Methods:

• Formulated motion prediction as an optimal control problem.
• Incorporated a biomechanical model and Hunt-Crossley contact force model.
• Proposed a novel 'free-fall method' for initial/final constraints and used direct collocation.

Main Results:

• Validated framework against experimental data.
• Predicted key biomechanical features like joint angles and forces.
• Revealed effects of prosthesis stiffness on amputee dynamics.

Conclusions:

• The framework accurately predicts sit-to-stand motion for transtibial amputees.
• Predictive simulation offers insights into prosthesis design and rehabilitation strategies.
• Potential applications include prosthetic design, rehabilitation, and humanoid robot motion planning.