Robust and optimal control

Due to their small sizes, microsystems and micromechatronic systems are very sensitive to environmental disturbances (temperature, vibrations, etc.) and to the interaction and contact with surrounding systems (manipulated objects, other microsystems) making their behavior time and tasks dependent. Additionally to these, most of them typify strong nonlinearities (high degree polynomial, hysteresis, creep/drift, …) as they are based on smart and active materials and exhibit badly damped oscillations as they include cantilever structures. All these phenomena need that the systems have to be controlled in order to reach the severe performances required in the applications (precise and high dynamics positioning). However additional challenges during the control synthesis are the low signal-to-noise ratio that are specific to micro-world and the lack of convenient sensors. The works of the CODE-team here consist in adapting the 'traditional' control techniques in order to include these properties (strong nonlinearities, badly damped oscillations, high environmental sensitivity, noisy signals, lack of sensors, time- and task- dependent models, …) when controlling micromechatronic systems and to satisfy the performances required in the applications. The adaptation may starts from the modeling, or during the controller synthesis. Different 'traditional' control techniques are studied for that: robust (H-inf, µsynthesis, RST,...), optimal (LQ, LQG,...), adaptive, multimodel and multimodal...

 

 

 Fig.1 Control of micromechatronic systems.

Applications of these control strategies include the characterization and nanomanipulation of DNA which require very high performances in term of bandwidth and precision, microassembly and micromanipulation and the precise positioning in general.

 

Selected publications

 

Mokrane Boudaoud, Yann Le Gorrec, Yassine Haddab, Philippe Lutz , An Output feedback LPV control strategy of a nonlinear electrostatic microgripper through a singular implicit modeling. Control Engineering Practice Volume 28, July 2014, Pages 97-111, 2014


Mokrane Boudaoud, Yassine Haddab, Philippe Lutz, Yann Le Gorrec, Noise characterization for high accuracy positioning of millimeter sized micromanipulation systems. Mechatronics, Vol. 21(6), Pages : 1087-1097, Sept 2011.


Didace Habineza, Micky Rakotondrabe and Yann Le Gorrec, 'Characterization, Modeling and H-inf Control of n-DOF Piezoelectric Actuators: Application to a 3-DOF Precise Positioner', Asian Journal of Control (AJC), DOI=10.1002/asjc.1224, Vol. 18, No. 5, pp. 1–20, September 2016.


Juan Antonio Escareno, Micky Rakotondrabe and Didace Habineza, 'Backstepping-based robust-adaptive control of a nonlinear 2-DOF piezoactuator', IFAC - Control Engineering Practice (CEP), Vol.41, Pages 57-71, August 2015.


Micky Rakotondrabe, Anthony Fowler and S.O. Reza Moheimani, 'Control of a novel 2-DoF MEMS nanopositioner with electrothermal actuation and sensing', IEEE - Transactions on Control Systems Technology (T-CST), Volume 22, Number 4, Page 1486-1497, July 2014.


Micky Rakotondrabe, Yassine Haddab and Philippe Lutz, 'Quadrilateral modelling and robust control of a nonlinear piezoelectric cantilever', IEEE - Transactions on Control Systems Technology (T-CST), Vol.17, Issue 3, pp:528-539, May 2009.

 

 

Contact

Yann Le Gorrec, yann.le.gorrec 'at' ens2m 'dot' fr
and

Micky Rakotondrabe, mrakoton 'at' femto-st 'dot' fr