Dotan Ilssar

GENERALRESEARCHPUBLICATIONS

dotan ilssar profile picture
PhD direct track 2012 –
Advisor: Prof. Izhak Bucher

Contact Details

Full CV – LINK

Office: Lady Davis Building 365

Tel: +972-77-8873605

Email: dotanilssar@gmail.com

Research interests

  • Structural dynamics, vibration
  • Near-field acoustic levitation
  • Control
  • Fluid-structure interaction dynamics

Current research

Acoustic levitation and propulsion of silicon wafers: accurate positioning rotation and traveling wave based transportation

Pictures  Videos

Pictures

Acoustic levitation height control experimental rig

Schematic layout and a photograph of an experimental setup, capable of levitating a designated object up to 200 micro meters. Left: The experimental rig showing the piezoelectric actuator in the middle and the levitated object with centering passive magnets (set aside for visibility). Right: The piezoelectric actuator and a sample levitated object.

 

 

Comparison between simulated dynamic responses,

Comparison between simulated dynamic responses, obtained using the well-known Reynolds equation based model (solid black curves), and the corresponding responses obtained from a simplified model developed in this research (dashed orange curves). It can be seen that the simplified model captures merely the more significant, slow dynamics of the system.

 

Control system scheme

Schematic layout of the closed loop system, comprising a PID gain-scheduled controller, a resonance tracking implementation and the physical acoustic levitation system.

 

 

Height control comparison between theory and experiment

A theoretical (orange curves), and its corresponding measured (blue curves) dynamic response of the closed loop, to an input reference, varying in steps between 60 and 180 micro meters.

 

Squeeze film experiential rig

Left: Photograph of an experimental rig, consisting a piezoelectric actuator, and a fixed object whose position can be adjusted using an XYZ stage. Right: Schematic layout of the piezoelectric actuator and the bottom surface of the fixed object.

 

Measured frequency response

The measured frequency response of the actuator’s excitation amplitude, under different average clearances. Dots – measured data, solid lines – fitted curves, corresponding to each individual clearance.

 

Ring experiential rig

Photograph of an experimental setup capable of producing flexural waves of different qualities (standing waves to traveling waves), on an annular plate. This apparatus is capable of levitating and rotating a carried object without contact. Moreover, by controlling the quality of the flexural waves produced on the annular plate, it is possible to accurately position the carried object. (Demonstrations are presented in the movies section)

 

Closed loop ring control results

Closed loop control of the levitated object. The presented graph shows the response corresponding to the fifth video in the video section.

 

Videos

An acoustic levitation device, operating at its second axisymmetric flexural mode. The sand stays at the nodal diameters.

 

A small mass, levitated above an ultrasonically oscillating driving.

A significant mass (~350 gr), levitated utilizing four levitation devices. This apparatus is capable of levitating large objects, such as silicon wafers.

A 200 mm silicon wafer, levitated and propelled using traveling flexural waves produced on an annular plate.

Non-contacting accurate angular positioning of a levitated object, using flexural waves, produced on an annular plate. In order to control the angle of the handled object, the presented device produces flexural waves of different qualities (standing waves to traveling waves) according to the error between the wanted angle and the measured angle. (A plot describing the time response of the levitated object appears in the pictures section).

PUBLICATIONS

  • D. Ilssar and I. Bucher, On the slow dynamics of near-field acoustically levitated objects under high excitation frequencies, Journal of sound and vibration, 2015. 354: p. 154-166.
  • D. Ilssar, I. Bucher and H. Flashner, Modelling and closed loop control of near-field acoustically levitated objects, Mechanical systems and signal processing, 2017. 85: p. 367-381.

 

Submitted papers

  • R. Gabai, D. Ilssar, N. Cohen, R. Shaham and I. Bucher, A rotational traveling wave based levitation device – Modelling, design, and control. Submitted to Sensors and actuators A: Physical, Aug. 16. ArXiv ID: 1608.06809
  • D. Ilssar and I. Bucher, The effect of acoustically levitated objects on the dynamics of ultrasonic actuators. Submitted to Journal of applied physics, Oct. 16.

 

CONFERENCES

Refereed papers in conference proceedings

 

  • D. Ilssar*, I. Bucher and N. Cohen, Structural optimization for one dimensional acoustic levitation devices – numerical and experimental study, International Conference on Noise and Vibration Engineering, ISMA, Leuven Belgium, September 2014.
  • I. Bucher*, D. Ilssar, R. Gabai, N. Cohen, R. Shaham and S. Davis, Controlled acoustic levitation – physical model and real-time digital implementation, IEEE International conference on Advanced Intelligent Mechatronics, Banff Alberta Canada, July 2016.
  • D. Ilssar*, I. Bucher and H. Flashner, Model based, nonlinear control of near-field acoustically levitated objects, International Conference on Noise and Vibration Engineering, ISMA, Leuven Belgium, September 2016.

 

Other conference contributions

  • D. Ilssar* and I. Bucher, On the dynamics of acoustically levitated objects – analytical and experimental study, The 33rd Israeli Conference on Mechanical Engineering, Tel-Aviv Israel, March 2015.
  • D. Ilssar* and I. Bucher, Modeling nonlinear effects on near-field acoustic levitation using slow-fast decomposition, Audio and Acoustic Signal Processing Workshop, Beer-Sheva Israel, October 2015.
  • R. Shaham*, D. Ilssar and I. Bucher, Resonance tracking and digital control of acoustically levitated objects, Audio and Acoustic Signal Processing Workshop, Beer-Sheva Israel, October 2015.
  • D. Ilssar*, Continuous Gain-Scheduling Control of Near-Field Acoustically Levitated Objects – Modeling and Experiments, GSC 2016 The Annual Workshop of Graduate Students in Systems & Control, Holon Israel, May 2016.
  • D. Ilssar*, I. Bucher and H. Flashner, Accurate vertical positioning of near-field acoustically levitated objects, using model based, gain-scheduling control, The 34th Israeli Conference on Mechanical Engineering, Haifa Israel, November 2016.
  • R. Gabai*, I. Bucher, D. Ilssar and N. Cohen, Acoustic Levitation and Propulsion Based on Traveling Waves Control, The 34th Israeli Conference on Mechanical Engineering, Haifa Israel, November 2016.