47 research outputs found
Memory-element based hysteresis:Identification and compensation of a piezoelectric actuator
Hysteresis phenomena can significantly deteriorate the performance when performing servo tasks with piezoelectric actuators. The aim of this brief is to model this nonlinear hysteresis effect and use this model to develop a feedforward controller that compensates for the hysteretic behavior. Exploiting the dual-pair concept, a connection is established between hysteresis models and general memory (MEM) elements examplified by the Ramberg–Osgood model. This facilitates both a straightforward identification procedure of a hysteresis model and a feedforward controller design. Both the identification procedure and the feedforward controller are implemented on a piezoelectric actuator indicating a performance improvement by a factor 3.5
Commutation-Angle Iterative Learning Control for Intermittent Data: Enhancing Piezo-Stepper Actuator Waveforms
Piezo-stepper actuators are used in many nanopositioning systems due to their
high resolution, high stiffness, fast response, and the ability to position a
mover over an infinite stroke by means of motion reminiscent of walking. The
aim of this paper is to develop a control approach for attenuating disturbances
that are caused by the walking motion and are therefore repeating in the
commutation-angle domain. A new iterative learning control approach is
developed for the commutation-angle domain, that addresses the
iteration-varying and non-equidistant sampling that occurs when the
piezo-stepper actuator is driven at varying drive frequencies by parameterizing
the input and error signals. Experimental validation of the framework on a
piezo-stepper actuator leads to significant performance improvements.Comment: 6 pages, 8 figures, 21st IFAC World Congress 202