Research on a valve-positioner pilot valve driven by a piezoelectric stack with self-sensing feedback

Area of Science:

• Automation Systems
• Control Engineering
• Mechatronics

Background:

• Piezoelectric actuation is crucial for high-performance automation systems requiring precise control.
• Existing systems face challenges with control accuracy and response speed in valve applications.
• Minute displacements from piezoelectric stacks need amplification for effective valve regulation.

Purpose of the Study:

• To propose a flexure-hinge displacement-amplification mechanism for piezoelectric valve control.
• To develop a self-sensing feedback composite controller to improve pilot-valve accuracy.
• To enhance overall system control by suppressing nonlinearities and hysteresis errors.

Main Methods:

• Designing a dual-output flexure-hinge mechanism for displacement amplification.
• Implementing a composite controller integrating feedforward control and piezoelectric self-sensing.
• Utilizing the piezoelectric element's self-sensing capability to avoid external sensors.

Main Results:

• The mechanism successfully amplifies piezoelectric stack displacement for pilot-valve regulation.
• The self-sensing controller effectively compensates for nonlinearities and hysteresis in the valve spool.
• Experimental validation confirms enhanced control accuracy and system performance.

Conclusions:

• The proposed displacement-amplification mechanism and self-sensing controller significantly improve piezoelectric valve control.
• This approach offers a sensorless solution for enhancing automation system precision.
• The findings contribute to advancements in high-accuracy, responsive valve control technologies.