Tiny "robots" that could perhaps someday help doctors examine organs, deliver drugs directly, or even perform microsurgery. But first researchers need to find reliable and accurate ways to control microscopic devices, which of course have little room for onboard power, sensors or propulsion. Scientists have previously used methods including magnetic and electrostatic forces, and attaching live bacteria. In the latest issue of the International Journal of Robotics Research, researchers from ETH Zurich demonstrate particularly deft control of a microbot, dubbed MagMite. MagMite, pictured here, is 300µm x 300µm (with a thickness of 70µm). It consists of two magnetized components, connected by a tiny spring. In the presence of a magnetic field, the two pieces try to bend toward each other, storing that tension in the connecting spring. By turning the magnetic field on and off very quickly, the researchers can use the loaded spring to propel the microbot forward, and by changing the direction of the magnetic field the microbot will turn.

The concept of building very small robots, and benefiting from recent advances in Micro Electro Mechanical Systems (MEMS). Due to their small size, microbots are potentially very cheap, and could be used in large numbers (swarm robotics) to explore environments which are too small or too dangerous for people or larger robots. It is expected that microbots will be useful in applications such as looking for survivors in collapsed buildings after an earthquake, or crawling through the digestive tract. What microbots lack in brawn or computational power, they can make up for by using large numbers, as in swarms of microbots.

Microbots were born thanks to the appearance of the microcontroller in the last decade of the 20th century, and the appearance of miniature mechanical systems on silicon (MEMS), although many microbots do not use silicon for mechanical components other than sensors.

One of the major challenges in developing a microrobot is to achieve motion using a very limited power supply. The microrobots can use a small lightweight battery source like a coin cell or can scavenge power from the surrounding in the form of vibration or light energy. Microrobots are also now using biological motors as power sources, such as flagellated Serratia marcescens, to draw chemical power from the surrounding fluid to actuate the robotic device. These biorobots can be directly controlled by stimuli such as chemotaxis or galvanotaxis with several control schemes available.

Nowadays, owing chiefly to wireless connections, like Wi-Fi (i.e. in domotic networks) the microbot's communication capacity has risen, so it can coordinate with other microbots to carry out more complex tasks.

Microrobotics has a wide range of applications at the bionic level. Some of the notable ones are:

Well, It doesn't stop here. A newer, and more advanced research is going on in the field of NanoRobots. This study can be termed as NanoRobotics. It deals with creating robotic machines close to the scale of several hundreds of nanometers. More specifically, nanorobotics refers to the still largely hypothetical nanotechnology engineering discipline of designing and building nanorobots, devices ranging in size from 0.1-10 micrometers and constructed of nanoscale or molecular components. As no artificial non-biological nanorobots have yet been created, they remain a hypothetical concept. The names nanobots, nanoids, nanites or nanomites have also been used to describe these hypothetical devices.

For those of you who are interested to learn more about this emerging technology, I suggest you take a look at the IRIS research on Nanorobotics.