Sep 8 2010
Engineers at Harvard University are researching on the development of microscopic aerial robots that could someday help to investigate environmental risks like forest fires and to perform rescue operations etc. Recently they have reported the development of a drivetrain called Passive Aeromechanical Regulation of Imbalanced Torques (PARITy), which is a millionth-scale automobile differential for regulating the air travel of these robots.
Their latest methodology is aimed at stabilizing these flying microrobots amidst strong aerodynamic forces and enabling their wings to flutter asymmetrically responding to bursts of wind, wing impairment and other environmental hindrances.
Pratheev S. Sreetharan, lead author of this research has stated that the drivetrain used in the aerial robots resemble a two wheeler automobile. He added that both drivetrains supply power to a pair of wheels or wings from a single supply. But the torque produced by PARITy is ten million times smaller than the car’s differential. PARITy differential is 5 mm long and its weight is one- hundredth of a gram. Other than the Harvard researchers, scientists from University of California, Berkeley, University of Delaware, University of Tokyo, and Delft University of Technology in the Netherlands are also researching.
In order to sustain erratic environmental conditions, microrobots have to flutter their wings like an insect in unison, a procedure involving both kinematics and aerodynamics. Sreetharan and his professor cum co-author Robert J. Wood found that a microrobot developed like an insect does not demand complex electronic feedback loops for accurately controlling its wing’ position.
Wood said that their novel design utilizes the concept of ‘mechanical intelligence’ for predicting the exact speed of the wing and the necessary amplitude for stabilizing the robot amidst various disturbing forces. This technology can rectify the imbalances by increasing or decreasing the wing speed on its own.
The researchers determined that confiscating a vital part of the microrobot’ wing, the auto correction provoked by the PARITy drivetrain permitted the robot to maintain its stability of flight. The smaller wings fluttered intensely to maintain the torque created by an integral wing, attaining an approximate speed of 6,600 beats per minute. The scientists stated that their inert method of controlling forces incurred during the robot’ flight is more desirable than the dynamic approach involving sensors and computation which can potentially increase the weight and complexity to the systems,meant to be light- weight and can make a buzzing sound of an insect while flying.
Source: http://www.harvard.edu