Self-sensing force control of a piezoelectric actuator

Area of Science:

• Engineering
• Materials Science
• Control Systems

Background:

• Piezoelectric actuators (PEAs) are widely used in precision engineering.
• Accurate force control of PEAs is challenging due to hysteresis and external load variations.
• Existing methods often rely on intrusive force sensors, limiting applications.

Purpose of the Study:

• To develop a sensorless closed-loop force control strategy for piezoelectric actuators.
• To propose a new PEA model incorporating asymmetric hysteresis and external force.
• To enable real-time estimation of actuator elongation and generated force.

Main Methods:

• A novel asymmetric hysteresis operator was integrated into a piezoelectric actuator model.
• A detection model was derived to compute elongation and force from driving voltage and current.
• The detection model replaced a physical force sensor in a closed-loop control system.
• Experiments were conducted using two PEAs, one as the controlled actuator and the other as a dynamic load.

Main Results:

• The proposed detection model accurately estimated PEA elongation and generated force in real-time.
• Sensorless closed-loop force control was successfully implemented.
• Good control performance was achieved across various mechanical loading conditions.
• The system demonstrated robustness against external disturbances.

Conclusions:

• The developed sensorless approach provides accurate and reliable force control for piezoelectric actuators.
• This method offers a cost-effective and practical alternative to traditional sensor-based control.
• The findings have significant implications for precision motion control and mechatronic systems.