I've done some basic current measurements, up a steep grade (about
25deg) in soft grass, the combined current drain is about 4amps, same
grade on concrete is about 2amps. downhill in grass is about 1.5amps and
downhill on concrete draws 1amp.
The robot was carrying it's own weight plus 2 6v 10amp batteries (about
4.4kg extra), I'd guess that the total weight was close to 10kg.
The speed uphill on grass was very slow and I'm going to run some tests
with larger wheels. Of course this will increase the load on the motors
but it might alleviate some of the sinking problems of the current size
wheel. The caster is also a problem having a diameter of about 85cm, it
tends to sink. This caster was the largest I could find in a hurry, I'll
try to find a larger one next week.
The wheels used in these tests had a diemeter of 175mm, the next set
will be 200mm.
The largest slope the chassis could climb was about 45deg, it was very
very slow but it did make it. The batteries I'm using are quite flat
also, I had planned on using a 12v 7amp battery but this was faulty and
wouldn't charge properly.
Dave Everett.