Investigation on the basic principles of human-machine contact force, based on screw theory

Area of Science:

• Robotics
• Biomechanics
• Mechanical Engineering

Background:

• Human-machine interaction involves complex contact forces.
• Accurate modeling of these forces is crucial for developing synergistic motion.
• Existing models may not fully capture the dynamics of spatial rigid body contact.

Purpose of the Study:

• To introduce a novel analytical method for spatial rigid body mechanics applied to human-machine contact.
• To establish an equivalent contact force model considering elastic deformation.
• To provide a theoretical foundation for human-machine synergetic motion.

Main Methods:

• Equating human-machine contact force to a spatially rigid body with virtual branches.
• Incorporating elastic deformation of virtual branch axes into the model.
• Solving for tension/compression and internal forces using pseudo-inverse and weighted generalized inverse solutions.
• Developing a deformation coordination equation for virtual branches.

Main Results:

• An equivalent human-machine contact force model was established.
• Analytical solutions for tension/compression and internal forces of virtual branches were obtained.
• The physical meaning of internal forces within virtual branches was clarified.
• Experimental validation confirmed the theoretical model's accuracy.

Conclusions:

• The proposed spatial rigid body mechanics model accurately represents human-machine contact forces.
• The model provides a theoretical basis for advancing human-machine synergetic motion.
• Experimental verification supports the model's applicability in real-world scenarios.