scholarly journals Modelling and Control of Piezoactuators for High Precision Positioning Systems Used in Radioactive Environments

2019 ◽  
Author(s):  
Pablo Serrano Galvez
Author(s):  
Ervin Kamenar ◽  
Saša Zelenika

Friction is one of the main disturbances in nanometric positioning. Recently, it was shown that ultra-high precision positioning typically happens in the pre-sliding motion regime where friction is characterized by an elasto-plastic nonlinear hysteretic behavior with a marked stochastic variability. With the aim of providing the tools for the development of robust control typologies for ultra-high precision mechatronics devices, different pre-sliding friction models are thus considered in this work. The most relevant ones are hence experimentally validated, as well as compared in terms of the complexity of identifying their characteristic parameters and of simulating the factual dynamic response. It is hence shown that the generalized Maxwell-slip model can account for all the important pre-sliding frictional effects in nanometric positioning applications. A thorough sensitivity analysis of the parameters of the generalized Maxwell-slip model model is therefore performed allowing to establish that three Maxwell-slip blocks are the minimum needed to approximate the behavior of the real precision positioning systems, six blocks allow representing excellently the real behavior, while the slower dynamics, which induces a difficult real-time implementation, with a very limited gain in terms of model accuracy, does not justify the usage of a larger number of elements.


2014 ◽  
Vol 658 ◽  
pp. 541-546 ◽  
Author(s):  
Mihai Avram ◽  
Victor Constantin ◽  
Constantin Bucşan ◽  
Daniel Besnea ◽  
Alina Spanu

Pneutronic systems come with a series of advantages that are natural to working with compressed air, such as the large power/weight ratio of pneumatic actuators, easy and affordable installation and maintenance as well as being clean working systems. However, due to working with compressed air, there are a series of issues, such as static and transient nonlinear behavior, mostly due to the high compressibility of air. Thus, the behavior of such systems is hard to control, especially in terms of precision positioning. The paper deals with proposing three hardware configurations of pneutronic positioning systems in order to assure the imposed positioning accuracy in the presence of disturbances and the preservation in time of the obtained position.


Author(s):  
Kam K. Leang ◽  
Gina Pannozzo ◽  
Qinze Zou ◽  
Santosh Devasia

In this article, we describe a collaborative approach to develop, integrate, and assess a teaching module on smart actuators specifically designed to embed topics in nano/bio technology into the undergraduate mechanical engineering (ME) curriculum. The collaboration involves three universities, each focusing on one specific aspect of the module. The module consists of lectures and laboratory activities that cover modeling and control of smart actuators for courses such as system dynamics, controls, and mechatronics. The integration of smart actuators — such as piezoelectric, shape memory alloy (SMA), and magnetostrictive based devices — into the ME curriculum is important because these devices are the workhorse in a multitude of nano and bio technologies. Thus, these devices play a critical role in the emerging areas, analogous to the benefits of the electric motor at the macroscale. But contrast to the well established coverage of the electric motor in the ME curriculum, modeling and control of smart actuators has yet to be systematically presented in core ME courses. The contribution of this article is presenting the systematic development, integration, and assessment of a teaching module on smart actuators. We first describe the design of lecture components using the piezo actuator as an example. The lecture materials cover core concepts within the framework of dynamics and controls, such as electromechanical coupling, dynamic response, nonlinear input-output behavior, and PID feedback control technique for high-precision positioning. Afterwards, we describe the development of a hands-on laboratory experiment designed to expose students to the basics of experimental modeling of the piezo actuator. The platform is also suited for basic control applications, and an example is presented to illustrate the application of piezo actuator control for high-precision positioning. The paper concludes with a discussion on how the module will be implemented and assessed at the three participating universities.


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