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Bionic-Bison-5535 / Bionic-Bison-2023-Competition-Robot

This is FRC team 5535's robot code for the 2023 competition.
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Robot balance when hanging over charge station edge #4

Closed WesleyMcGinn closed 1 year ago

WesleyMcGinn commented 1 year ago

Introduction:

The charge station is 96 inches wide. A typical robot (probably over 95% of the robots we will see this year) will be 30 inches in width at the frame perimeter, with an additional 2.5 inches of bumper added to each side. This makes the typical robot 35 total inches wide, thus revealing that the charge station only has room for only 2.7 robots (not 3) when they are completely pressed up against each other. Our robot is a trapezoid, 30 inches in width at the front and much less at the back. By rotating our robot so that a front wheel hangs over the edge of the charge station, we can shrink our charge station space down to less than 20 inches including bumpers. That is a 43% decrease in robot width, leaving room for two typical robots on the charge station with a plentiful three inches of space between each robot.

Problem:

Unfortunately, when we try to drive one wheel over the edge of the charge station, the robot tips and, as a result, slides down the side of the charge station. In order to be counted as docked or engaged with the charge station, a robot must be fully supported by it. Our robot slides until is is touching the floor when it tips over the edge.

Potential Solution:

We could make a small peg that would actuate out of the bottom of the robot when driving over the edge. The peg would perform the job of the dangling wheel, holding up the weight of the robot at that corner and keeping the robot's center of mass within the imaginary polygon that is formed by the parts of the robot that are in contact with the charge station. Ideas for this peg are already incorporated into about.pdf, while they have not been added to the actual robot programming.

WesleyMcGinn commented 1 year ago

The code is now finished for the peg, and we are using two PWM actuators to hold the robot up. The pegs can be actuated by pressing down the left stick on the primary controller during final mode, or it can be actuated/retracted by the triggers on the secondary controller at any time.

The branch labeled peg will now be pulled to main.

WesleyMcGinn commented 1 year ago

Update and Removal:

The peg feature is no longer in use. Why? The peg was removed for the following reasons:

The New Solution:

Because the robot was so tippy, we lowered the bumpers so that they will stop us from tipping too far. We still sometimes tip up to ten degrees to one side, but it isn't so bad and we don't think that we will be tipping all the way over.

Because of the lowered bumpers and our trapezoidal shape, we can drive right over the edge of the charging station without falling over the edge. We then take up, at most, 22 inches on the side of the charge station, leaving two inches between each robot if the other two are typically sized and evenly spaced.

So...

New code must be written to accommodate for the following two tasks:

WesleyMcGinn commented 1 year ago

Actually, Nevermind....

At the Lakeview2 Competition, we tried hanging over the edge and discovered that we actually can't on plexiglass. We can do it on our practice field because the charge station is made of wood, but we slip right off the edge if we go an inch too far on the actual field. We did, however, discover that our trapezoid shape allows us to wedge between two robots on the charge station easily and cleanly.

Therefore, we will be using this strategy (since it works so well) rather than the strategy that has been designed and troubleshooted above. There is therefore no necessary continuation of this issue.