A parallelogram-based compliant remote-center-of-motion stage for active parallel alignment

Area of Science:

• Mechanical Engineering
• Robotics
• Nanotechnology

Background:

• Precision alignment is critical for micro-/nanomanipulations.
• Conventional stages often suffer from unwanted lateral displacement.
• Remote-center-of-motion (RCM) mechanisms are essential for out-of-plane aligning.

Purpose of the Study:

• To develop a novel parallelogram-based compliant RCM stage for active parallel alignment.
• To enhance precision and minimize lateral displacement in micro-/nanomanipulation tasks.
• To design a stage with adjustable operating space without compromising rotational precision.

Main Methods:

• Development of a symmetric double-parallelogram mechanism (SDPM) using flexure hinges for RCM.
• Utilizing piezoelectric actuators for driving and non-contact sensors for motion measurement.
• Analytical modeling (kinematics, statics, dynamics) based on pseudo-rigid-body simplification.
• Dimensional optimization for maximizing the first resonance frequency.
• Finite element analysis (FEA) for model validation and prototype fabrication.

Main Results:

• The developed RCM stage demonstrates a rotational range of 1.45 mrad.
• The maximum center shift of the RCM point is minimized to 1 μm.
• Analytical models were validated through FEA and experimental testing.

Conclusions:

• The proposed compliant RCM stage effectively achieves precision out-of-plane alignment.
• The design minimizes harmful lateral displacement, crucial for micro-/nanomanipulations.
• The compliant mechanism offers advantages for precision tasks requiring controlled motion.