ecole!doctorale!smaer! ! engineering practice vol 39, pp. 12 - 22, 2015. title microsoft word -...

Ecole doctorale SMAER Sciences Mécaniques, Acoustique, Electronique, Robotique

_______________________________________________________________________________________________________________________________________ ED SMAER (ED391)

Tour 55-‐65 Bureau 208-‐ case courrier 270-‐ 4, place Jussieu -‐ 75252 PARIS Cedex 05 ': 01 44 27 40 71

[email protected] Sujet de thèse_1617

_______________________ Thesis subject 2016 Laboratory : Institut des Systèmes Intelligents et de Robotique (ISIR) University: Université Pierre et Marie Curie Title of the thesis: Robust position and force control of nanorobotic systems for automated manipulation of Carbon NanoTube (CNT) inside a Scanning Electron Microscope (SEM). Thesis supervisor: Stéphane Régnier Email contact: [email protected] Co supervisor: Mokrane Boudaoud Collaborations within the thesis: no Program affiliation: / Cotutelle: / University : / This subject can be published on the doctoral school’s web site: yes

Thesis’s summary (abstract): In the last decade, nanotechnologies have enabled several technological breakthroughs in electronics, mechanics, biology and medicine thanks to the development of the so-called nanostructures [1][2]. Nanostructures have dimensions in the mesoscale (100 nm- 10µm), they can be observed and treated in the vacuum chamber of a Scanning Electron Microscope (SEM) and they require dedicated tools for its manipulation, characterization and transportation. The aim of the thesis is to develop new methodologies for (i) the robust position and speed control of nanorobotic systems based on piezoelectric stick slip actuators and (ii) the robust force control at the nanoNewton level for the manipulation of a CNT. In application point of view, the objective is to provide new methodologies to perform fully automated tasks on nanostructures inside a SEM, which has never been demonstrated until now. ______________________________


_______________________________________________________________________________________________________________________________________ ED SMAER (ED391)



Subject

Scientific issues and objectives:

The thesis will focus on robust control methodologies taking into account the specificities of nanorobotic systems as well as the specificities of nanostructures.

Position control: the objective is to perform precise and speed motions of the nanorobotic system into a target position. The main issue is to control the dynamic of the nanorobotic system taking into account the fact that piezoelectric S&S actuators have a limitation in terms of speed. In stick and slip operating mode, the actuator is controlled by an input sawtooth voltage. The maximum velocity is proportional the maximum amplitude and frequency of the input voltage that can be applied. The maximum velocity of such kind of actuators is in the range of several tens of millimeters per second. This is not sufficient for fast assembly tasks. A new idea that will be studied in the thesis is to control the elongation of the piezoelectric actuator (by U_scanning in Fig1) to increase its bandwidth in the stick motion and both the frequency and the amplitude of an input voltage signal (voltage U_stepping in Fig1) in the stick and slip phase. This new approach allows obtaining more degrees of freedom to control the velocity of the actuator for large displacements. Additionally, the velocity of the actuator depends on the amplitude of the contact friction force between the piezoelectric material and the nanorobotic axis. Results of the friction characterization for different values of pressure in the working environment will be used to design a robust controller. The idea consists on taking into account in real time the value of the friction force amplitude using an observer to adapt the parameters of the controller aiming at achieving speed positioning tasks of the nanorobotic structure toward a target position. Indeed, the friction force depends on the velocity of the actuator and the pressure of the environment. For certain values of the velocity and the pressure, the friction force has minimum amplitude. If the actuator is working around this operating point, speed motion of the actuator can be obtained. This characteristic has never been taken into account in control design of this class of actuators. Usually simple sawtooth voltage with controlled amplitude and frequency are used [3].

Fig 1: Bloc diagram of the closed loop control scheme

Force control: force measurement will be needed in two cases, for contact detection and for gripping force control. The gripping force measurement and control is needed to overcome adhesive force between a nanostructure and the substrate and to perform a handling operation without destruction of the manipulated nanostructure. For the thesis, the end effector will be a micro-gripper with two force sensors, one for the contact detection and the second one for the measurement of the gripping force.

Friction FfVelocity dq/dt

Pressure

Elementary stick slip actuator of the nanorobotic

system

Scanning mode controller

Observer

Stepping mode controller Position q

Velocity dq/dt

Friction force Ff

U_stepping

Time

U_stepping

U_scanning

U_stepping

TimeFriction force Ff

Target position qt


_______________________________________________________________________________________________________________________________________ ED SMAER (ED391)



The gripping of a nanostructure such as CNT is very difficult because of the high ratio between its length and diameter (often more than 100) and the high range of variation of its stiffness. At the micrometer scale, the stability of the gripping force control is no longer satisfied when the stiffness uncertainty of the manipulated object is not taken into account for the force controller design [4]. To deal with dimensions of the nanostructure the novelty of the method that will be developed in the thesis is to measure and to control the gripping force along two directions (Fig.2). The first direction Fx is along the length of the nanostructure and the second direction Fy in the orthogonal direction. To deal with stability specifications of the controller with respect to the uncertainty of the nanostructure stiffness, robust control methodologies based on the multimodel methodology will be studied [4].

Fig 2: Piezoelectric microgripper with bidirectional motion capability

The fabrication of the microgripper will be performed with the private company PERCIPIO ROBOTICS in Besançon (France). The fingers of the microgripper must integrate at their tip two AFM (Atomic Force Microscope) cantilevers. The resolution of the integrated sensors must be in the nanoNewton range because the adhesive force between a CNT of 1µm in length and 100 nm in diameter and the substrate is about 100 nN. Taking into account the required resolution, the force sensors will be designed using the capacitive principle.

The thesis must include three main contributions:

- Robust position control methodologies of the nanorobotic system.

- Robust gripping force control along two axes.

- Automated pick and place operation on a CNT inside a SEM. The thesis must contain a strong experimental contribution.

Required qualifications: The expected candidate must have a multidisciplinary profile with specific skills on, automatic control (Hinf, LPV, LMI, state feedback) and on robotics.

Fingers of the microgripper

CNT

FxFx

Fy Fy

(a) (b)

(c)


_______________________________________________________________________________________________________________________________________ ED SMAER (ED391)



[1] S. J. Tans, A. R. M. Verschueren and C. Dekker. Room-temperature transistor based on a single carbon nanotube. Nature, vol. 393, pp. 49-52, 1998. [2] C. J. Gannon, P. Cherukuri, B. I. Yakobson, L. Cognet, J. S. Kanzius, C. Kittrell, R. B. Weisman, M. Pasquali, H.K. Schmidt, R.E. Smalley and S.A. Curley. Carbon nanotube-enhanced thermal destruction of cancer cells in a noninvasive radiofrequency field. Cancer, vol. 15, pp. 2654-2665, 2007. [3] Rakotondrabe, M. Y, Haddab. & P, Lutz. Voltage/Frequency Proportional Control of Stick-Slip Micropositioning Systems. IEEE Transactions on Control Systems Technology, vol 16, pp. 1316-1322, 2008. [4] M. Boudaoud, M. G. De Faria,Y. Haddab, S. Haliyo, Y. Le Gorrec, P. Lutz and S. Régnier. Robust Microscale Gripping Using a Self-Scheduled Dynamic Controller: design and real time implementation. Control Engineering Practice vol 39, pp. 12 - 22, 2015.

Two major publications in the domain of the thesis proposal:

1- J-O. Abrahamians, B. Sauvet, J. Polesel-Maris, R. Braive, and S. Régnier. A Nanorobotic System for In Situ Stiffness Measurements on Membranes. IEEE Transactions on Robotics. Vol 30 No 1 Pages 119-124, 2013. 2- M. Boudaoud, M. G. De Faria,Y. Haddab, S. Haliyo, Y. Le Gorrec, P. Lutz and S. Régnier. Robust Microscale Gripping Using a Self-Scheduled Dynamic Controller: design and real time implementation. Control Engineering Practice vol 39, pp. 12 - 22, 2015.

ecole!doctorale!smaer! ! engineering practice vol 39, pp. 12 - 22, 2015. title microsoft word -...

Documents