Visual Tracking for Electron Microscopy

Robotics continues to provide researchers with an increasing ability to interact with objects at the nanoscale. As micro- and nanorobotic technologies mature, more interest is given to computer-assisted or automated approaches to manipulation. Although actuators are currently available that enable displacement resolutions in the subnanometer range, improvements in feedback technologies have not kept pace. Thus, many actuators that are capable of performing nanometer displacements are limited in automated tasks by the lack of suitable feedback mechanisms. My work proposes the use of a rigid-model-based method for end effector tracking in a scanning electron microscope to aid in enabling more precise automated manipulations and measurements. These models allow the system to leverage domain-specific knowledge to improve performance in a challenging tracking environment.

Mobile Microrobots

Primary challenges in the building of untethered sub-millimeter sized robots include propulsion methods, power supply, and control. We developed a novel type of microrobot termed Magmite that utilizes a new class of Wireless Resonant Magnetic Micro-actuator (WRMMa) which accomplishes all three tasks. The device harvests magnetic energy from the environment and ectively transforms it into impact-driven mechanical force while being fully controllable. It can be powered and controlled with oscillating fields in the kHz range and strengths as low as 2 mT, which is only roughly 50 times the average earth magnetic field. These microrobotics agents with dimensions less than 300 um x 300 um x 70 um are capable of moving forward, backward and turning in place while reaching speeds in excess of 12.5 mm/s or 42 times the robot's body length per second. The robots produce enough force to push 150 um x 20 um gold disks and can be visually servoed through a maze in a fully automated fashion. The robustness of our robots and systems leads to high experimental repeatability, which in turn enabled us to win the RoboCup 2007 Nanogram Competition in Atlanta, GA, USA.

Application of Helical Microstructures

Few rotational actuators currently exist with the ability to transmit motion at different speeds, torques, and directions at the nanometer scale. We have worked to apply helical nanobelts as linear-to-rotary and rotary-to-linear motion converters. This conversion is based upon their ability to rectify device rotation to linear motion for untethered microrobotic applications as well as their application as rotary sample stages for nanoscale imaging.