Current integration force and displacement self-sensing method for cantilevered piezoelectric actuators

Area of Science:

• Materials Science and Engineering
• Mechanical Engineering
• Electrical Engineering

Background:

• Piezoelectric cantilevers are widely used in sensors and actuators.
• Material nonlinearities such as creep and hysteresis in piezoelectric materials hinder accurate sensing.
• Existing methods often struggle to provide reliable real-time measurements of both displacement and applied force.

Purpose of the Study:

• To develop and validate a novel self-sensing method for piezoelectric cantilevers.
• To accurately measure both displacement and external applied force at the cantilever tip.
• To compensate for material nonlinearities (creep and hysteresis) in integrated electric current measurements.

Main Methods:

• Integrated electric current compensation using the Prandtl-Ishlinskii model for hysteresis.
• Auto-regressive and moving average exogenous (ARMAX) model to minimize creep influence.
• Quasistatic estimation, electronic circuit design, and long-term charge preservation considerations.

Main Results:

• The proposed method enables self-sensing of both displacement and applied force.
• Experimental validation showed force self-sensing errors below +/-8% with a 20 V peak-to-peak input signal.
• Effective compensation of material nonlinearities was demonstrated.

Conclusions:

• The developed method offers a reliable approach for simultaneous displacement and force self-sensing in piezoelectric cantilevers.
• The compensation strategies effectively address material nonlinearities, enhancing measurement accuracy.
• The technique shows promise for applications requiring precise force and displacement monitoring.