Friday, March 5, 2010

Ornithopters, very interesting and cool..

Every Robotics and Tech geek dream about making small things which can fly by themselves. Ornithopters are the aircraft stimulating a bird which can fly by flapping the wings attached to it! Sounds very different and  weird, right? look at the following video to get some basic Idea.



Well, I had some more videos lets take a look, then will come to see its internals .



The above one looks very much modern and flies much comfortably.


Coming to its internals,

First it needs a high-powered motor and then a gear drive to convert circular motion to linear(not perfect linear, it depends on the wings) and then a battery or power source for motor.



Till now We have seen Motors pump drive water or drive gears etc..But seeing the need of the project we need a very low-weight motor which can drive at higher-speeds  with high torque having high weight/torque generated ratio. So, brushless Motors are preferred , Any of the 2 types of these Motors,  inrunner brushless or outrunner brushless can be used.

baffled about these two types of Motors??

In Inrunner, Coils(electro Magnets) are Outside and Permanent Motors are inside and when coils are switched On and OFF accordingly permanent magnets rotate.So, shaft is attached to permanent Magnets.

Outrunner are inside-out of Inrunner Motors. Coils are around shaft but not attached to it and permanent motors are outside and when coils are switched On and Off permanent magents rotate which are attached externally to shaft making it to rotate as per Faraday’s laws.

TIP: Best available brushless motors are the vibrators in our mobiles.Yeah, they are core-less and no iron-core in armature.



Gear Drive-train


This is one of the most important job to be done perfectly. Most electrical guy topple seeing this task. Its best to consult a good mechanical guy and make things simple. look the the following video to get why this is tough for Electrical guys..





The most important part is motivating the motor to the needed level of  flight digesting the load of aerodynamics,losses in flapping wings,gears etc..We have constraints of weight but as we reduce the battery weight powering the Motor for long enough becomes difficult . So, in conclusion only Li-Poly (Lithium Polymer) batteries are recommended. Rechargeable Li-Poly are best for long run.They do have some drawbacks regarding safety and short-life but they suit for this application. In the end, Li-Poly battery of 200g can carry a 400g Ornithopter not for more than 20 min.


That's it from ma study on these Ornithopters , You can update nfo by comments and I welcome it . :D


Lets see some more astonishing videos where Ornithopters are small as a finger and as light as feather



(The above one is totally crazy) just 2.5 Cm wings and 920mg weight ??? superb, buddy!!