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.
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.
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.
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.
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.
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.
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
4.0 in(W) x 3.9 in(L) x 3.25 in(H)
1/16 in. aluminum angle, Wedge is 1/8" Lucite
C written in the SouceBoost IDE
7.4V from a two cell 2200mAH lithim-ion battery pack.
A linear regulator steps the voltage down to 5V for the PIC.
Four Solarbotics GM11 right angle gearmotors.
L293D driven by microprocessor
Software generated Pulse Rate Modulation.
4WD using four motors
Four 1.25 inch aluminum wheels from Solarbotics.
Three IR obstacle sensors and two IR line sensors.