Model-free robust motion control for biological optical microscopy using time-delay estimation with an adaptive RBFNN...

Area of Science:

• Optical microscopy
• Precision engineering
• Control systems

Background:

• Large numerical aperture microscopy demands higher precision, range, and load capacity in objective motion carriers (OMCs).
• Existing OMCs face challenges in meeting these advanced requirements due to limitations in precision and control.
• Nonlinear friction in mechanical components like ball screws degrades motion accuracy.

Purpose of the Study:

• To develop an innovative objective motion carrier (OMC) with enhanced precision and load-bearing capacity.
• To implement a robust nonlinear motion control strategy for mitigating friction in ball screw mechanisms.
• To validate the effectiveness of the novel OMC in high-resolution bio-optical microscopy.

Main Methods:

• A novel OMC utilizing a ball screw mechanism as the primary drive.
• A nonlinear motion control strategy integrating fast nonsingular terminal sliding mode, experimental estimation, and adaptive radial basis neural network.
• Lyapunov theory for demonstrating closed-loop control system stability.

Main Results:

• The developed controller significantly mitigates nonlinear friction in the ball screw mechanism.
• Maximum error reduced by 33% and root mean square error by 34% compared to other sliding mode control strategies.
• Successful implementation of the OMC in a high-resolution bio-optical microscope.

Conclusions:

• The novel OMC with its advanced control strategy meets the precision demands of modern microscopy.
• The system demonstrates superior performance in reducing motion errors caused by nonlinear friction.
• The OMC is effective for high-resolution microscopic imaging, particularly for biological samples such as retinal organoids.