GRACE Project: model-based control of a nonlinear actuator

Oscar Fonseca Aguilar, Mauricio Muñoz Arias, Doekele Stavenga


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Natural phenomena have proven to be a great source of inspiration for developing specialized devices. Insect compound eyes offer promising insights for the development of new artificial navigation and vision systems. In recent years, a Goniometric Research Apparatus for Compound Eyes (GRACE) has been developed. The aim of the apparatus is to obtain a rapid mapping of compound eyes. Initially a non-automatized system was used. The apparatus has been automatized into a specialized mechatronical device with 6 degrees of freedom, with an upper and lower optical stage and a digital camera. In the last upgrade an auto-focusing algorithm sets the position of the studied insect using the sharpness of the image by controlling the position of Motor Z. Motors X and Y adjust the lateral position, depending on the image details. To control the position of the camera system, which is attached to a Zeiss microscope in the upper stage, a highly nonlinear actuator for a Elero DC motor has been developed. The actuator holds the microscope, which, due to a lead screw, is severely affected by gravity and a high friction coefficient. An energy-based model is here applied using the port-Hamiltonian framework (pH), taking the mass of the system in the screw as an external force, and based on the self-locking property. An optical rotational encoder is the sensor used in the actuator. Experimental results can be obtained with a longitudinal accuracy of the microscope position of 5 micrometers. The developed GRACE system allows the massive collection of detailed images of insect eyes, i.e. of flies and butterflies.
Originele taal-2English
TitelBenelux Meeting of Systems and Control
Plaats van productieLommel, Belgium
UitgeverijKU Leuven
Aantal pagina's1
StatusPublished - 21-mrt.-2019
Evenement38th Benelux Meeting on Systems and Control 2019 - Lommel, Belgium
Duur: 19-mrt.-201921-mrt.-2019


Conference38th Benelux Meeting on Systems and Control 2019

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