Wall Bot (WallB)
WallB is my first attempt at creating a robot that can carry a load down a hallway; specifically a small tool box. I'm constantly carrying my briefcase in one arm and a tool box in the other. The tool box weighs roughly 10lbs and its bulky shape makes it annoying to lug around. The idea came to me after reading about Steve Norris's "RoboStool". My project is split into 3 steps detailed below.
Step 1: Test Motors and Sensors
WallB takes its first steps using the Parallax Motor Mount Kit postion controllers to pulse the HB-25's (Parallax DC Motor Controller). Test code written to take forward distance from wall and calculate how many rotations to move until appox. 50cm away; WallB then moves to that distance and continues to keep that distance. First test run went great!
See for yourself: WallB Test 1(YouTube)
Step 2: Make it Follow Walls
WallB's preliminary code completed. HB-25's directly pulsed from the SUMO BS2; Motor Mount Kit position controllers not in use. Test results were great!
See for yourself: WallB Test 2(YouTube)
This weekend I took WallB out to a school with long hallways. Minor tweaks in the code made it go straight and smooth at home but when the environment changed, it went back to fish tailing. This was due to the IR sensors sensitivity to different color walls. I'm going to swap the corner IR sensors out for some more Ping sensors. Hopefully this problem will go away.
See for yourself: WallB Test 3(YouTube)
WallB has received some upgrades in the brain department. I switched out the BS2's for a Propeller. I finally sat down and learned the basics of Spin, which was enough to make WallB work. Right away I saw an improvement in overall reaction to sensor data. I also figured out what was making WallB fishtail so much. Turns out the HB25 motor controllers aren’t putting out the same voltages. The right wheel is receiving .3v less than the other. I think its my wiring but since this is a prototype setup I decided to fudge the pulse numbers to make it go straight.
See for yourself: WallB Test 4(YouTube)
Step 3: Make it Follow Me
I wasn’t too excited to start this part of the project after reading other peoples troubles with this subject, but I seemed to have stubbed into a simple method for solving this. It happened while I was testing WallB's wall following capabilities when it ran out of wall and started to follow my leg instead. It was surprising how well it worked. I actually just put all my gear onto it and had it follow me to the car. It was like my sidekick. Unfortunately I didn't have anyone to hold the camera so its at a weird hard to see angle. The concept is simple, the bots senses my legs and tries to keep a certain distance. When my legs go too far it keeps turning until it finds them again(pretty much how it follows walls).
See for yourself: WallB Follow Test 1(YouTube)
For similar project see TheGrue's "TOBI"