Characterization and Validation of a Hysteretic Dynamic Non-Linear Piezoceramic Actuator Model-Edición Única

Abstract

The use of smart materials as actuators and sensors has experienced a great expansion in recent years, mainly in the aerospace, automotive, civil engineering and medical fields. From all of the existent smart materials, piezoelectric ceramics have gained significant attention among researchers, mainly due to their fast response operation and considerable strain and force output. Their use as actuators can be divided into three main categories: positioners, motors and vibration suppressors. Limitations on the use of piezoelectric materials include various nonlinearities in their operational behaviour, such as hysteresis, material nonlinearities, frequency response, creep, aging and thermal behaviour. This thesis presents an improved model for piezoceramic actuators, which accounts for hysteresis, dynamic response and nonlinearities. The hysteresis model is based on the widely used General Maxwell Slip model. An electro-mechanical non-linear model replaces the linear constitutive equations commonly used, and a linear second order model compensates the frequency response of the actuator. A specific piezoceramic actuator is selected for full and detailed experimental characterization. The model is built in a Matlab/Simulink environment, and validated via experimental results. Based on the same formulation, two other models are also proposed: one that is intended to operate within a force-controlled scheme (as opposite to the first model, which is based in a displacement/position control), and a piezoceramic actuator inverse model, implemented for an open-loop control scheme, which compensates nonlinearities to obtain a “linearized” behaviour of the actuator. Simulations are carried out using open and closed loop control theory, including a mechanical interaction with a finite element model of a cantilever beam.