Stiffness Analysis of Parallel Cable-Driven Upper Limb Rehabilitation Robot.

Area of Science:

• Robotics
• Biomechanics
• Mechanical Engineering

Background:

• Rehabilitation robots require precise control and predictable motion.
• Understanding the static stiffness of parallel cable-driven systems is essential for performance.
• Upper limb rehabilitation robots (PCUR) present unique challenges due to complex human biomechanics.

Purpose of the Study:

• To derive and analyze the static stiffness of a parallel cable-driven upper limb rehabilitation robot (PCUR).
• To investigate the influence of cable tension, arrangement, and stiffness on the overall robot stiffness.
• To understand the motion characteristics and position changes of the moving platform under varying stiffness and external forces.

Main Methods:

• Derivation of the static stiffness expression, separating platform pose stiffness and cable pose stiffness.
• Development of a simulation model using MATLAB/Simscape Multibody.
• Application of cable tension to achieve static equilibrium and analysis of motion under varied stiffness and external forces.

Main Results:

• The static stiffness of the PCUR is a function of platform pose stiffness and cable pose stiffness.
• Key factors influencing PCUR stiffness include cable tension, cable arrangement, and individual cable stiffness.
• Analysis revealed distinct motion laws for the moving platform under different stiffness conditions and external forces.

Conclusions:

• The derived stiffness expression provides a basis for optimizing PCUR design.
• Accurate modeling of stiffness is critical for enhancing the performance and safety of upper limb rehabilitation robots.
• This research contributes to the development of more effective and predictable robotic rehabilitation devices.