Browsing by Subject "Cross coupled control"

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Open Access
Learning based cross-coupled control for multi-axis high precision positioning systems
(ASME, 2012-10) Geçer-Ulu, Nurcan; Ulu, Erva; Çakmakçı, Melih
In this paper, a controller featuring cross-coupled control and iterative learning control schemes is designed and implemented on a modular two-axis positioning system in order to improve both contour and tracking accuracy. Instead of using the standard contour estimation technique proposed with the variable gain cross-coupled control, a computationally efficient contour estimation technique is incorporated with the presented control design. Moreover, implemented contour estimation technique makes the presented control scheme more suitable for arbitrary nonlinear contours. Effectiveness of the control design is verified with simulations and experiments on a two-axis positioning system. Also, simulations demonstrating the performance of the control method on a three-axis positioning system are provided. The resulting controller is shown to achieve nanometer level contouring and tracking performance. Simulation results also show its applicability to three-axis nano-positioning systems. Copyright © 2012 by ASME.
Open Access
Modeling and cross coupling controller development for a 6DOF laser micro-machining system
(IEEE, 2017) Kerimoğlu, Serhat; Çakmakçı, Melih
In recent years, studies on manufacturing systems have proved the importance of cooperation of positioning systems with laser cutting technology. The performance of the manufacturing system can be improved by utilizing both laser and positioning systems together. In this study, modeling and cross coupling controller development of a micromachining system which can perform on non-linear contoured surfaces is presented. Laser micromachining system is designed and assembled including a nanosecond Q-switched pulsed fiber laser, a 6-DOF hexapod manipulator, a granite table in order to absorb vibrations and an external cabin system to isolate the whole system for safety and health issues. The positioning system used here has fast response and precise positioning capabilities with a wide range of workspace. However, its performance of machining non-linear surfaces can be further improved by using a cross coupled control algorithm. On top of the loop based controllers an add-on controller is developed to improve the contouring performance by including the effects of the other feedback loops on the overall controller. Actual laser cutting results also show improvements due to the improvements in the positioning system performance.