Sensorless model-based displacement estimator for piezoelectric actuator through a practical three-stage mechanism

Area of Science:

• Materials Science and Engineering
• Mechanical Engineering
• Electrical Engineering

Background:

• Piezoelectric elements (PEMs) are crucial components in various applications requiring precise motion.
• Accurate displacement measurement of piezoelectric actuators (PEAs) is essential but often hindered by the cost and limitations of traditional sensors.
• Sensorless control methods are gaining traction as a viable alternative for indirect displacement estimation.

Purpose of the Study:

• To develop a novel, simple, and sensorless method for estimating the displacement of a piezoelectric actuator with a three-stage amplification mechanism.
• To validate a hybrid algorithm that utilizes electrical signals (voltage and current) for enhanced displacement accuracy.
• To provide a cost-effective and adaptable solution for precise motion control in piezoelectric actuator systems.

Main Methods:

• Development of a new sensorless method for a piezoelectric actuator (PEA) incorporating piezostack elements and a three-stage amplification system.
• Utilizing a basic external circuit to indirectly measure actuator displacement by analyzing electrical signals.
• Introduction and experimental validation of a hybrid algorithm leveraging piezoelectric material voltage and current measurements to estimate displacement.

Main Results:

• The study successfully developed and validated a simple sensorless control algorithm for piezoelectric actuators.
• The hybrid algorithm demonstrated enhanced accuracy in displacement estimation by correlating electrical charge (via current) with mechanical displacement.
• Experimental confirmation of the algorithm's efficacy was achieved using a laboratory setup.

Conclusions:

• A straightforward sensorless control algorithm was presented, offering a promising avenue for future research in piezoelectric actuator control.
• The simplicity of the theoretical model and the sensorless technique allows for broad applicability across diverse piezoelectric actuators and amplification systems.
• This research streamlines the design, modeling, and control strategy development for various actuators by employing an uncomplicated, adaptable estimation algorithm.