We have learned a lot from the beginning of this FTC season to where we are now.
This is our progress:
Brainstorming overall robot:
Pretty basic design we thought off to start with. The idea was to quickly prototype then refine.
Basic idea is that we will have
6 wheel drive train
A collector on one end that will pass the minerals under the robot to a basket that will be lifted up on the other end to deposit in lander so that the robot doesn’t have to turn around.
Drive train THOUGHTS:
Our initial thought was to design a 6 wheel drive train. This was based on research we did online and saw in several YouTube videos where the virtues of the 6 wheel tank drive were extolled.
For some reason we decided to be too clever by half and designed a drive train using only 2 motors.
So the quick and dirty prototype was built:
Needless to say, this did not reliably cross the crater. The middle wheel would lift off the ground and there would be no traction to go forward.
So we had to come with a way to drive all of the wheels. We still stuck with using only the two motors. Each would drive 3 wheels. In order to do this, we had to solve many problems that crop up:
Motor couldn’t be attached to the middle wheel directly as it would be two low to clear the crater. This could have worked if we had 6 inch or larger wheels perhaps, but we only had the Rev kit’s 90 mm (less than 4 in) wheels.
Hence motor had to be above the wheel and drive the wheel via a gear.
This meant that the other wheels would also need to driven by gear to preserve the rotation direction
Since wheels are far apart, need to drive the other wheels via chain drive
Attaching a chain to three wheels requires chain tensioners as well, since it slips otherwise.
Drive train:
After a couple of weekends of building, we had this:
After another build session (this time on a Sunday with only build team), we had a complete chassis:
It was able to move around, though it was very unstable. We decided to add another extrude to each end, to hold the gears and tensioners in place(only did gears for now, and only one side of the robot)
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