Determining the three-dimensional relation between the skeletal elements of the human shoulder complex.

Area of Science:

• Biomechanics
• Robotics
• Human Motion Analysis

Background:

• Understanding human shoulder joint motion is crucial for biomechanics and robotics.
• Existing methods often rely on Euler angles, which can present challenges in complex kinematic analysis.
• A standardized and mathematically robust method for describing joint coupling is needed.

Purpose of the Study:

• To develop an inverse kinematics method for determining human shoulder joint motion coupling.
• To translate Euler-angle-based coupling equations into the Denavit-Hartenberg (DH) framework.
• To establish a new joint motion coupling relationship using experimental data.

Main Methods:

• Utilized analytical inverse kinematics to transfer Euler-angle coupling equations to the DH method.
• Represented end-effector positions using both Euler angles and DH parameters for specific human postures.
• Applied polynomial and cosine fitting to DH joint angles derived from various postures.

Main Results:

• Successfully transferred Euler-angle-based shoulder joint coupling to the DH method.
• Obtained DH joint angles for different human postures by equating Cartesian end-effector positions.
• Developed a new joint motion coupling relationship based on the fitted DH joint angles.

Conclusions:

• The proposed inverse kinematics method provides a robust way to represent human shoulder joint coupling using the DH convention.
• This approach facilitates a more standardized and computationally tractable analysis of shoulder biomechanics.
• The findings contribute to advancements in human motion analysis, robotics, and prosthetic design.