TY - JOUR

T1 - Image-based discrete-time optimal feedback control for an optomechanical derotator

AU - Altmann, Bettina

AU - Pape, Christian

AU - Reithmeier, Eduard

N1 - Conference code: 17

PY - 2018

Y1 - 2018

N2 - An optomechanical derotator is an optical system that can be used to extend various measurement methods so they can be applied to rotating measurement objects. The function principle is to manipulate the image of the rotating measurement object by means of rotating reflective components inside the derotator. Thus it appears stationary in the measurement data. For this it is inevitably that the angular position and velocity of the derotator are controlled in such way that they always amount to half that of the measurement object. It is therefore necessary to adjust the derotator with the help of an implemented controller. Since we want to acquire the reference input of the control with a high-speed camera and image processing algorithms the sampling time of the control must be adapted to the rather long computation time of the image processing. As a result, the use of analog control techniques is prohibited so that a digital controller has to be implemented. This paper proposes an approach where an image-based discrete-time linear-quadratic regulator is used to satisfy the requirements concerning the angular position and velocity of the derotator. To improve its performance, it is supplemented by integral action and a model-based feedforward control. Furthermore, the image processing algorithms by which the reference input of the control is determined are described. Finally, it is demonstrated that this controller concept produces the desired result by generating a standing image of a rotating object with a camera and the derotator.

AB - An optomechanical derotator is an optical system that can be used to extend various measurement methods so they can be applied to rotating measurement objects. The function principle is to manipulate the image of the rotating measurement object by means of rotating reflective components inside the derotator. Thus it appears stationary in the measurement data. For this it is inevitably that the angular position and velocity of the derotator are controlled in such way that they always amount to half that of the measurement object. It is therefore necessary to adjust the derotator with the help of an implemented controller. Since we want to acquire the reference input of the control with a high-speed camera and image processing algorithms the sampling time of the control must be adapted to the rather long computation time of the image processing. As a result, the use of analog control techniques is prohibited so that a digital controller has to be implemented. This paper proposes an approach where an image-based discrete-time linear-quadratic regulator is used to satisfy the requirements concerning the angular position and velocity of the derotator. To improve its performance, it is supplemented by integral action and a model-based feedforward control. Furthermore, the image processing algorithms by which the reference input of the control is determined are described. Finally, it is demonstrated that this controller concept produces the desired result by generating a standing image of a rotating object with a camera and the derotator.

KW - discrete-time linear-quadratic regulator

KW - discrete-time optimal feedback control

KW - image-based control

KW - model-based feedforward control

KW - Optomechanical derotator

UR - http://www.scopus.com/inward/record.url?scp=85058151214&partnerID=8YFLogxK

U2 - 10.1016/j.ifacol.2018.11.398

DO - 10.1016/j.ifacol.2018.11.398

M3 - Conference article

AN - SCOPUS:85058151214

VL - 51

SP - 292

EP - 297

JO - IFAC Proceedings Volumes (IFAC-PapersOnline)

JF - IFAC Proceedings Volumes (IFAC-PapersOnline)

SN - 1474-6670

IS - 32

T2 - 17th IFAC Workshop on Control Applications of Optimization

Y2 - 15 October 2018 through 19 October 2018

ER -