Line of sight controller tuning using Bayesian optimisation: application to a double stage stabilisation platform

ABSTRACT

The inertial stabilisation of the line of sight of an imager fixed on a mobile carrier is considered in order to acquire good quality images despite the disturbances generated by the carrier. A double stage mechanical stabilisation architecture is proposed, where a second stabilisation stage, based on a piezoelectric actuator, is added to the usual structure. The piezoelectric actuator transfer function and hysteresis are characterised through experiments. In order to design the controllers of both stages, a high-level image quality criterion (the modulation transfer function (MTF)) is considered, together with design constraints on the main variables of interest. The criterion and the constraints are evaluated by realistic simulations based on some input and noise profiles measured on a real-life system. The MTF evaluation being time-consuming, a Bayesian optimisation method specially dedicated to expensive-to-evaluate functions is used to obtain the parameters of the controllers. The obtain experimental results are displayed and their performances discussed.

Keywords:

• Line of sight
• stabilisation
• Bayesian optimisation
• modulation transfer function
• piezoelectric actuators

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 The modulus margin is the distance between the Nyquist plot of the open loop transfer function $L\left(j\omega \right)$ and the critical point ($-1$); it can be expressed as $Mm=\underset{\omega }{min}|L\left(j\omega \right)+1|$

Additional information

Notes on contributors

Sophie Frasnedo

Sophie Frasnedo obtained her engineering degree diploma from the Ecole Supérieure d'Electricité in 2013 and her PhD from the Université Paris-Sud in 2016 on the optimization of control laws based on high level criterions. She is currently with RTE, a French company working on electicity transport networks.

Guillaume Sandou

Guillaume Sandou was graduated from the Ecole Supérieure d'Electricité in 2002. He obtained his master degree, his PhD and his “Habilitation à Diriger les Recherches” from the University Paris-Sud in 2002, 2005 and 2012 respectively. His is currently a full professor in CentraleSupélec where his research interests deal with the use of optimization for the design of control laws.

Gilles Duc

Gilles Duc was graduated from the Ecole Supérieure d'Electricité in 1978. He obtained his PhD and his “Habilitation à Diriger les Recherches” from the University Paris-Sud in 1981 and 1997 respectively. His is currently a full professor in CentraleSupélec where his research interests deal with robustness analysis and robust control.

Cédric Chapuis

Cédric Chapuis obtained his engineering degree diploma from the ESIEE in 2009 and his PhD from the INSA Lyon in 2012. From 2012 to 2016, he was with Safran Electronics and Defense where he worked on the Line of Sight stabilization. He is now with Renault, a French car manufacturer, where he is in charge of parking system studies.

Philippe Feyel

Philippe Feyel was graduated from the Ecole Supérieure d'Electricité in 2000. He obtained his PhD from the University Paris-Sud in 2015. He is currently a Senior Control Expert in Safran Electronics and Defense. He is also the head of the Expertness Chair on Control; Modelling, Image and Signal Processing.