In case of Conventional Robots Actuators are either Electrical or Hydraulic/Pneumatic actuators.But in case of Micro-Robots following types of actuators are used.
Several types
Thermal
based on principle of Bi-Metallic strip.
Piezoelectric.
Electrostatic motors but based on Electrostatic Principle.
Magnetic
Thermal Micro- Actuators:
Principle is based on Bi-Metalic strip effect. It is basically cantilever micro-actuator.it is very easy to fabricate multilayered structure with MEMS technology.We can have cantilever by any of conventional process & we can add layer of another material to this cantilever. This Bi-Metallic structure is heated by many ways either by passing hot fluid or by resistive heating . Because of different coefficients of thermal expansions we will get differential expansion of Bi-metalic strip which can be used for actuation.
Piezoelectric Micro-actuators:
When voltage is applied across some materials, strain will be produced. These materials are compatible with MEMS based fabrication processes.One of the material is SiO2.Suppose the patch of such material is formed over a cantilever & if voltage is applied across that piezo patch it will bend. This kind of Actuators are popular in Atomic Force microscopy (AFM).
Cantilever beam magnetic Micro-Actuator:
Here the Magnetic bead is placed on the top of Cantilever.Copper coil is used lower side of Epoxy substrate through which electric current is passed. Magnetic field formed because of this will attract the magnetic bead due to which we will get desired movement.
Now we will see fabrication process for Cantilever beam magnetic Micro-Actuator.
