Precise manipulation and autonomous assembly of micro and nano-sized structures.
Goal
To develop a robotic manipulation system that can autonomously construct complex three-dimensional micro and nano-structures from micro and nano-parts. To develop a large-scale assembly system to mass-assemble micro and nano-devices.
Approach
Using a 3-axis piezo-electric positioning stage with sub-micrometer to sub-nanometer precision, the control of an end-effector in a micro to nano-sized workspace is realized. Using an Optical Microscope as an imaging device for the micro-scale, or an Atomic Force Microscope as an imaging and manipulation device at the nano-scale, the workspace can be imaged. Vision processing can detect objects in the workspace; combined with high-level task planning, paths can be formulated to assemble the micro or nano-parts in a user-defined configuration.
The physical manipulation of objects can be realized by using nano-probes such as an AFM or STM tip as a two-dimensional manipulator. Three-dimensional manipulators including micro-fabricated grippers, laser trapping methods, and dielectrophoretic techniques can be implemented.
Current Status
A micromanipulation system is developed that can autonomously construct two-dimensional micro-arrangements of spheres sized from 3um to 20um in diameter. The assembly system consists of: (1) A nano-probe, (2) a three-axis piezo-electric stage (100x100x15um range in x,y,z) that is controlled digitally in a realtime operating system (RTAI Linux) and holds the nano-probe, (3) a three-axis coarse positioning stage that the sample is mounted to, (4) a high-powered optical microscope using a 50x objective (~500x zoom), and (5) a camera and frame-grabber allowing the workspace to be imaged, providing a sensory feedback for the control loop.
In the control, the user specifies a particle arrangement the manipulation system should achieve. Using the Hough transform, objects in the workspace are detected, and using a Wavefront expansion planner, paths are generated to attain the goal state. Finally the nano-probe is servoed on the path, pushing the particles, until the goal state is achieved.
Current efforts include extending the system into the nano-scale by investigating Atomic Force Microscopy as an imaging and manipulation device.
Benefits
The development of certain micro and nano-devices, particularly complex three-dimensional structures such as micro-fabricated motors, are performed manually. This is not feasible for low-cost large-scale manufacture, however an autonomous assembly system can solve this problem. Complex micro and nano-devices will be more readily available and can be incorporated into more complicated systems.
Videos
Video 1: Pushing a 10um microsphere [5MB]
Video 2: Creating the letter M with microspheres [20MB]
Members
Cagdas Onal,
Chytra Pawashe,
Metin Sitti
Publications
C. D. Onal and M. Sitti, ''Visual Servoing Based Autonomous 2D Manipulation of Microparticles using a Nanoprobe,'' IEEE Trans. on Control Systems Technology, 2007, in press.
C. Pawashe and M. Sitti, ''Two-Dimensional Vision-Based Autonomous Microparticle Assembly using Nanoprobes,'' Journal of Micromechatronics, vol. 3, no. 3-5, pp. 285-306, 2006. pdf
A. Tafazzoli, C. Pawashe, and M. Sitti, ''Force-Controlled Microcontact Printing using Microassembled Particle Templates,'' Proc. of the IEEE Robotics and Automation Conference, pp. 263-268, Orlando, FL, May 2006. pdf
M. Sitti, ''Teleoperated and Automatic Control of Nanomanipulation Systems using Atomic Force Microscope Probes,'' Proc. of the IEEE Conf. on Decision and Control, Maui, Hawaii, Dec. 2003. (Invited Paper) pdf
M. Sitti and H. Hashimoto, ''Controlled pushing of nanoparticles: Modeling and experiments,'' IEEE/ASME Trans. on Mechatronics, vol. 5, no. 2, pp. 199-211, 2000. pdf
