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Anger Management

Update

Updated: 6/20/08
Anger Management won first place in the 2006 AHRC Robot Rally Mini Sumo contest. With a record of 5-1 the robots performance was very impressive.



Updated: 6/10/08
After some testing the original NiCD batteries were abandoned in favor of bulkier lithium-ion cells. The new batteries give the robot a virtually unlimited run time in the ring. The original 150maH NiCD could not compare to the 2200maH lithium-ion cells. This battery change did however force a significant change in the chassis. The robot lost that really low profile look. But, you can't win them all.



Old Robot Profile

Here is a shot of the original setup using the NiCD cells. The robot has a nice low profile. The batteries tucked nicely in between the motors and the chassis rails.




New Robot Profile

As you can see the profile is not as pretty as before. The GIANT green thing in the middle is the new battery pack. It gives the robot a new sense of power.





Inspiration

Anger Management was being built to compete in the 2006 AHRC Robot Rally Mini Sumo contest. All of he code was written with the BoostC compiler. The robot sports 4 wheel drive and custom IR Sensors. I wanted a robot that was sleek and lo profile to get under the opponents sensors. The project went through several iterations of tweaking different mechanical parts before arriving at the final version. The robot for the chassis is constructed from 1.5" aluminum angle that has been cut down to allow the motors to mount in from the sides. The from wedge is made from a piece of Lucite that was machine into a slick weapon.



Propulsion

As stated before the robot uses four Solarbotics GM6 motors fitted with aluminum wheels. This gives the robot a heap load of traction as well as the ability to turn in place. The motors are driven by an L293D. The left hand and right hand motors are in parallel pairs. i.e. the two left motors and in parallel and the two right motors are in parallel. The motor paralleling does create some problems. If one motor shorts then both motor grind to a halt. But because space was an issue four separate motor drives just was not an option. The motors are drive with a software generated PWM signal from the micro.




Obstacle Sensors

In order to see ones opponent sensors must be employed. Anger Management uses three custom IR sensors. The IR LEDs are pulsed both 600us at 56kHz and the signal is detected by an IR receiver. The receiver is the type that you would find in a DVD player or TV. The sensor was built in filters that try to reject signals that are not modulated at 56kHz. The IR LEDs are pulsed 6 times and the output of the sensor is monitored. If four of the six times there was a reflection detected then the robot reacts to the object.




Line Sensors

The robot uses two QRE1114 IR emitter/IR Photo transistors to detect the line. The sensors have a fairly limited range so they have to be placed very close to the ground.




Robot Brain

The robot is driven by a PIC16F819 @ 8MHz. The micro monitors all the sensors and takes the appropriate when a sensor is triggered. The algorithm used was a "If you see something, run into it" type brute force thing. If the front sensor triggers the motors go to full power and do not stop unless the center sensor is deactivated. This brute force programming turned out to be a problem as if you get too robots that just push and they are evenly matched, the to robots just spin there tires. The controller board was point to point wired as I did not want to make a circuit card. Not my best job but it got the job done.




Push Push Push

This is how most of the rounds with Two-Pics went. Anger Management went through the rest of the field with almost no problems.




Anger Management Data Sheet

Robot class Mini Sumo
Size 4.0 in(W) x 3.9 in(L) x 3.25 in(H)
Weight 465 grams
Frame 1/16 in. aluminum angle, Wedge is 1/8" Lucite
CPU Microchip PIC16F819
Programming
Language
C written in the SouceBoost IDE
Power 7.4V from a two cell 2200mAH lithim-ion battery pack.
A linear regulator steps the voltage down to 5V for the PIC.
Motors Four Solarbotics GM11 right angle gearmotors.
Motor driver L293D driven by microprocessor
Speed Control Software generated Pulse Rate Modulation.
Drive System 4WD using four motors
Tires Four 1.25 inch aluminum wheels from Solarbotics.
Sensors Three IR obstacle sensors and two IR line sensors.

Anger Management code and schematics

This information is supplied in the hope it may be useful but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose.






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