High-performance magneto-rheological clutches for direct-drive actuation: Design and development

Area of Science:

• Robotics and Control Systems
• Materials Science
• Mechanical Engineering

Background:

• Robotic manipulators require high-performance actuation systems.
• Existing Magneto-Rheological (MR) clutches face limitations in torque-to-mass ratio.
• Optimizing MR clutch design is crucial for advanced robotic applications.

Purpose of the Study:

• To present an improved design for high torque-to-mass ratio MR clutches.
• To develop MR clutches as the primary actuation mechanism for a five-degrees-of-freedom robotic manipulator.
• To enhance the torque-to-mass ratio through multiple design optimizations.

Main Methods:

• Optimized Hall sensor configuration for indirect torque measurement without affecting magnetic reluctance.
• Hybrid design incorporating electromagnetic coils and permanent magnets to improve magnetization.
• Gap size reduction in hybrid MR clutches to enhance torque and dynamic range.
• Finite Element Analysis (FEA) for design validation and performance prediction.
• Development and experimental testing of MR clutch prototypes.

Main Results:

• Achieved significant improvements in the torque-to-mass ratio of MR clutches.
• Validated the effectiveness of the new Hall sensor arrangement and hybrid magnetization.
• Demonstrated the impact of gap size reduction on clutch performance.
• Successfully developed and tested MR clutch prototypes with torque capacities from 15 to 200 N·m.
• Experimental results confirmed the accuracy of the FEA and the proposed design.

Conclusions:

• The proposed MR clutch design offers a superior torque-to-mass ratio for robotic manipulators.
• The hybrid design, optimized sensor configuration, and gap reduction are key to enhanced performance.
• The developed MR clutches are validated for practical application in robotic systems.