Multi-Layer Control with Disturbance Observers for a Long-Travel Dual-Stage Precision Positioning Platform

Area of Science:

• Robotics and Control Systems
• Precision Engineering
• Microfabrication

Background:

• Precision positioning platforms are crucial for microfabrication.
• Achieving nanometre-level accuracy over long travel ranges presents significant challenges.
• Existing control methods often struggle with external disturbances and model uncertainties.

Purpose of the Study:

• To investigate the impact of disturbance observers on a long-travel precision positioning platform.
• To develop and validate a multi-layer control architecture for enhanced accuracy and robustness.
• To demonstrate the platform's utility in micro-lens fabrication.

Main Methods:

• Development of a multi-layer control architecture integrating disturbance observers, feedforward compensation, gain-scheduling, and control switching.
• Experimental identification of dynamic models for motor and piezoelectric transducer (PZT) stages.
• Implementation of distinct control strategies for PZT and motor stages.
• Validation through simulations and experimental testing.

Main Results:

• Significant improvements in positioning accuracy and robustness were demonstrated.
• The integrated control structure enabled nanometre-level accuracy within 10 cm travel ranges.
• Successfully fabricated micro-lenses with evaluated optical properties.

Conclusions:

• The proposed multi-layer control structure, incorporating disturbance observers, significantly enhances precision positioning.
• The platform is well-suited for high-precision microfabrication tasks, such as micro-lens production.
• This approach offers a robust solution for demanding precision engineering applications.