Rector's Gold Medal

Awarded to the best project in 24th convocation of Pakistan Navy Engineering College, a constituent college of NUST.

http://dawn.com/2012/12/29/202-get-degrees-at-pn-engineering-college-convocation/

The adventure concludes

Notice the new handlebar ? Something we never really cared about, but have to admit, it looks good :D

SubukRaftar featured in Daily Nai Baat

21-07-2012

SubukRaftar winner at NED SENTEC Project Exhibition '12

SubukRaftar receives 1st prize in EMCOT 2012

Held at COMSATS Institute of Information Technology (CIIT), Abbottabad from 7-8 May, 2012. Around 70 projects coming from various universities of Pakistan participated in the Hardware and Software categories.

CIIT - ECOT 2012 Official News Page

The eye-catching nature of the project intrigued everyone visiting the exhibition to ask details and many even offered to buy the vehicle including the Chief Guest, Qazi Mohammad Asad, Minister for Higher Education, KPK.
 

SubukRaftar goes to Procom.Net '12

Comes back with Runner Up prize in the Hardware Exhibition :)

Steering control added, PID Tuned..... Surging forward !

 

Final look of the circuitry

Finally .... we have liftoff

Starting off with the lightest jobless person we have :p

The 20Ampere fuse didnt melt on this weight.... but blew up in 3-4 minutes when loaded with a 65kg person.
24V x 20 A = 480 Watts !!!

The battle ends

After countless burnouts, tries and retries, we finally got IR2110 to work..... after that it was a matter of shifting all the circuits to PCBs, making a power distribution board with fuses etc. till someone could stand on it.

Deciding about the placement of circuits

 

Finally, everything is mounted and ready to go.....

The MOSFET driver battle

Honestly, it's a hell of a tiring and mind screwing job :@

The trouble with MOSFET drivers is that they never work .... and when they do, you never know why :/
So here goes the standard circuit of IR2110 which works like a charm

  

Important Technical Note: The Low side supply voltage MUST NOT EXCEED 12V ... all over the internet we found +15V but it blows out the low side IRF1404. There are 12V protection zener diodes between every mosfet's gate and source. The bootstrap capacitors are 47uF electrolytic with 0.1uF ceramic cap in parallel. Bootstrap diodes are 1n4007 because the schottky ones would blow. The PWM frequency is 2.1 kHz approx. that explains the beeping sound when the motors run. Anti-parallel diodes on 22ohm(or 10ohms because we were out of 22 ohms) resistors at all high side gates are schottky.

Even probing the high side output of mosfet driver with repect to ground can "sometimes" damage it. It is better to see its waveform referenced to that MOSFET's source terminal.

Special Thanks to the segfault guy and application notes that helped us a lot. :)

It's alive !!!!!

Adding the integral and derivative controls, some gain adjustments through hit and trial and here we go......

Quite jerky, but it's an achievement ! Weeeeeeeeeee :D ok, back to work now !

This is what we're talking about....infact, something like this

The opamp shortcut proved to be worth it (will put schematics later) ! The motor controller gave a smooth control response. Charged with excitement, we connected both motors to the same hbridge. Adjusted the gains for pure proportional control, the motors moved in the tilted direction.

Temporary mounting for the IMU

Sticking it all together with electric tape :D

Adding a little counterweight..... otherwise it would keep leaning and hence moving towards one side

Couldnt find anything except pliers, so here it goes

This is balanced without power. Let's plug in the power and do some gain fine tuning with our trusty USBTiny.

4 N-Channel MOSFET H-bridge

 

It's actually IRF1404, nice little HEXFET costing Rs. 90.

But driving it ........ very challenging !

We tried IR2110, but mosfet driver blues were taking to much time so we jumped to a shortcut we accidentally learned at NERC 2010. Using an external battery to drive the high side mosfets :D

This is what the mosfet driver gave us

A headache ! and this ....

 Total disaster :(  we can bet you can't make an oscilloscope do that :P