fcuk?

fcuk stands for Fast Cargo Unloading King!

The place...

This was a robot that I built for a robotics competition, Yantriki conducted at the Indian Institute of Technology, Bombay in February 2002. The competition was a part of Techfest 2002, an annual technology festival at IITB.

The competition...

The competition was conducted in three levels. The first two levels were for manually controlled robots (an entirely different game) and the third level were for the autonomous robots.

The game...

The game is simple - the robot is placed in an arena (a rectangular wooden board) where a docking station (a cylindrical GI pipe) was fixed in the center behind a wall). At the blow of the whistle, the power supply to the robot is turned on. From there on, the robot, completely autonomous in its operation, should detect the docking station and unload its cargo (five marbles) successfully into the station.

The rules...

The rules of the game and other details can be accessed at http://www.me.iitb.ernet.in/yantriki/ruleslevel3.htm

The arena...

The design...

One design aspect of fcuk that took many participants by surprise was that the robot was purely mechanical in its operation...no sensors and no electronics (there were a few contact switches). This gave the robot a great advantage in terms of its speed. This was a decision that was made based entirely on the game rules - the points formula. A higher weightage was given to speed than accuracy. Hence, all those sophisticated robots that used sensors and processors never had a realistic chance of winning the competition.

The chassis of the robot was borrowed from a toy car. The frame was modified to fit a pair of powerful internally geared DC motors directly to the wheel hubs. This gave fcuk the capability of making a differential turn. The power source...a pair of 1.5V dry cell.

The marbles were preloaded inside a L-shaped PVC pipe (used for electrical insulation) that was fixed to the frame at a strategic angle. These marbles were held from dropping down against a latch. When the latch was pulled, the marbles fell down due to gravity.

The latch was designed to pull off at the force of the robot hitting the wall in front of the docking station.

For accuracy and direction, there were a pair of probes fitted to the front of the car. These probes had contact switches in their front ends. The logic behind the design was the fact that the robot was unaware of the side from which it started the game. This necessitated the use of a detection mechanism that could dynamically manipulate its strategy based on the direction.

When the robot hits the wall on either direction at an angle, the corresponding probe touches the wall closing the contact switch at that end. This cuts the power supply to motor on the closed switch end, while the other motor is still being powered. This produces a differential turning that straightens the robot orientation with respect to the wall, thus alligning the unloading mouth exactly on top of the docking station.

The force of impact while alligning causes the latch to be pulled off, and the marbles unload automatically into the station!

The robot was mechanically calibrated by position probes fitted to the sides and back to account for the accuracy with which the robot striked the wall.

The elims...

fcuk had a great beginning to its campaign by clearing the elimination round in style. The task was to drop a single marble inside a ring within a time limit. fcuk clocked 2.6 seconds in its very first attempt and was seeded sixth out of 36 entries.

The D-Day performance...

fcuk unloaded 2 marbles in the first trial clocking 2.23 seconds, and unloaded all the five marbles clocking 2.12 seconds in the second trial. This earned fcuk the fifth position out of the 31 qualified partipants.

A few visual memories...

fcuk at the docking station unloading the cargo

Thats me positioning the robot before deployment

The group.... (from left) Arun Kumar, Me, R. Arun and Shanthakumar

Some of the robots at the competition