Looks like a lot of weight high and on the back. what’s the weight and height?
He is only 80lbs, and it is about 5’5".
Looks like this might be top heavy when you deploy the arm.
A few of Chuck’s features:
Physical:
2 CIM motors powering high-traction wheels via chain/sprocket system
Shielded electronics case
Highly mobile and fast
3/4 of the robot’s total weight centered over drive wheels, providing unparalleled traction for our weight
Incredibly light, coming in at 90 pounds including battery, 77 without!
I-frame arm construction prevents bending and twisting
Electrical/programmed:
Effective autonomous mode
Shielded wiring and programming redundancy protects against sensor damage
Programmed in such a way that it will refuse to break itself
Incredibly simple to drive
State programming enables robot’s arm and wrist to return to a given position if bumped
Code has the ability to “learn” what the robot’s current state is and some possible deficiencies, then work around them
Now for a few quick anecdotes…
Our arm, one might say, looks very heavy. Extremely heavy. Heavy enough that one wonders how that tiny fisher-price motor manages to lift it. However, it isn’t so.
The arm is constructed out of a fiberglass/foamboard combination material that is extremely durable and strong, but very light. The whole arm weighs less than 5 pounds, and with the wrist and claw added it’s still less than 7 pounds.
Some of our mentors were… shall we say, rather skeptical about a material this light. “How will it hold up under pressure?” they asked. “Won’t it break off as soon as we try to use it?”
After an unfortunate incident involving a badly damaged ceiling fan (11-12 feet up, I might add–this robot will certainly be capable of scoring ringers on the high goal!) set to high speed, a completely undamaged arm and claw, and a team mentor spending several hours attempting to bend the brass fittings of his fan back into shape, the murmers stopped.
Our team members also were rather reassured after the robot slammed its arm into our rack at near full speed during the early stages of driving practice, shifting the full-size rack but not even putting a nick in the arm.
The robot is certainly back-heavy, however to date due to the control algorithms and other factors we have been pretty much unsuccessful tipping it unless we were absolutely trying to tip it. Also, all the major weight pieces (battery, drive motors, major structural elements) are fairly low, giving us a low COG. This also gives us enough traction to climb ramps easily.
Nice green. is that your arm?
Yes it is.
HOWLY thats a huge green arm:P wow it looks…big
was there a reason for how thick you arm is? I understand its light, but did it need to be so thick for lets say support??
It is only 1" thick.
For one, small quantities of this material are rather difficult to produce. For another, the larger the quantity of material, the more stable it is. We decided fairly early on an I-shaped beam for this design of an arm, and the fiberglass/foamboard material fit the bill perfectly. The thickness of the arm’s pieces is in this case dictated by the width of the foamboard “core” of the material, the width of the pieces were chosen by the material necessary to withstand certain forces and the necessity of embedding plywood in certain points to prevent screws pulling through the material, and finally the width of the arm assembly was chosen as being excellent for:
- Mounting our wrist and claw inside, leaving joints less exposed to being hit
- Running a cable/chain link between a motor on the back frame and the wrist
- Running all wires, cables, and the claw control rope down the center of the I structure
All that said, it also looks cool. 
ahah we were thinking about nicknaming our robot chuck
its probably just gonna be the nothern knight
I’m not sure really. I started calling him Chuck because…I don’t remember. I guess it just stuck.