We did not finish but we got so much done today and last night. We finished creating all the components for the compound gear ratio, and axles for the gears. We also printed an addition large gear for the gear coupling forward reverse system. We still have to print the connector for that system and the specially modified gear for the left to the right system, in addition to the chassis to hold everything together.
We also used super glue to completely make the motor system strong. The axle and small gear were super glued to one end of the connector today. And I super glued the wires to the motor. However, there was a catastrophic failure that could set us back a long time. One of the parts of the battery pack looks destroyed. It has blackened and shriveled, probably the result of an accidental short circuit. We need to get a replacement battery back and then somehow get that all hooked up to the motor.
Overall though, it is starting to come together.
We are probably not going to finish by day 10 unfortunately, but hopefully, we will be able to get a lot of pieces printed overnight and while I am in school, and then maybe we will be able to finish within the next few days or so.
Today we finally got our motor connector working. Previously even slight load torques would cause the connector to stop spinning, but we used super glue to fuse it together. Unfortunately, it was way more powerful than we thought and @AaronD'Souza-U04J5CM3T46 and I both cut our fingers. Our gear ratio is going to need to be quite a lot but it's manageable.
In addition, we got 2 of our wheels printed. The holes were a tiny bit too small and there was stringing inside for one of them, but I fixed this issue by soaking a skewer in boiling water and rapidly moving it through the hole, which deformed the plastic.
We completely finalized the mechanism design but 3D modeling is going to take a while. We are starting by printing all of the necessary components we already have the files for.
Here is a video of test #3 of the new motor connector (keep in mind this already a 1:6 ratio so the small gear is spinning 6x faster) and also a picture of all the parts we have printed so far
Day 4,5,6,7 -
We just got back from Florida today so we didn't really do much on days 4, 5, and 6, although we did do a bit of some visualization of how some of the mechanisms work in a more specific way.
Today we designed and printed a bracket that perfectly lined up the gears that we printed so far. (Image foreground)
We also modeled our wheels. We don't have enough time to print those today, but you can see a hazy picture of the 3D model in the background. I might end up printing one wheel overnight and check it out in the morning.
I finally got the robot mechanisms worked out. Here is a very rough sketch of the first piece of paper that I stumbled upon. This design should allow the robot to go, forward, backward, left, and right, and even stop with just a single lever, a bunch of gears, and a motor that is continually turning in one direction. Here is how it works:
On the left side, we can see the side view. There are two gears that mesh together on a pivoting bar. Attached to the bottom gear are the wheels. If the lever is pushed all the way to one side, the top gear will touch the drive gear and act as the idler gear, so the bottom gear will travel in the same direction as the drive gear. If the lever is pushed to the other side, then the bottom gear will directly touch the drive gear, and it will travel in the opposite direction. If the lever is put in the middle, then neither the top nor bottom gear will touch the drive gear, and the robot will not move. This is how our robot goes forward, backward, and stops.
On the right side, we can see the front view of the wheel system. Most of our axles are tight square axles that spin with the gears and lock tightly in place, but the axle in our wheels is a loose circle that doesn't turn with the wheel. We can see in this side view that our bottom gear is actually very thick/long, and has 4 rods poking out of either side. This gear will easily be able to slide left and right when the lever is slid left and right. When the lever is slid to the left, the rods interlock with the holes between the spokes of the left wheel, but not the right wheel. When this gear turns, the left wheel will turn, but the right wheel will not. The same applies to the right side. Also when the lever is in the middle, it interlocks with both wheels, allowing the robot to go straight. This is how our robot can turn left and right.
Also, @AaronD'Souza-U04J5CM3T46 and @BrendenD'Souza-U04JC0N6ZC2 uploaded all of our finalized files from Day 1 and Day 2 to the SD card for our printer so they are all readily available to be printed.
We are going on vacation to Florida for 4 days because of a wedding, so we won't get much done then. Hopefully, we can get some CAD files done for the robot when we are sitting in the hotel, but we will be pretty busy and we can't do any printing.
We didn't get a lot done today because we had a lot of schoolwork, but we designed and printed a new axle since the old one didn't fit well. This one is 0.1 mm smaller lengthwise and heightwise. Now our dimensions and designs for the axles, gears and connectors should be finalized.
As a reminder, @AaronD'Souza-U04J5CM3T46 and @BrendenD'Souza-U04JC0N6ZC2, and I are building a mechanically-codable robot. We are going to have to make a revision to our design. Originally we were going to make it read the input from a wheel with gears, but now we are going to make either 1 or 2 levers that control whether the robot is going forward or backward, and also left or right. Once again there is no coding or microprocessors, all the information for how the robot moves and turns are not controlled by the motor, but by the gears and the physical layout of the plastic pieces. We have a general idea of how this going to work, but we need to do a lot more designing.
We had previously done some testing with tolerances in a gear meshing a couple days ago. Not all of our prints are shown (we had a bunch of fails where the tolerance didn't line up, or the printing didn't succeed, or we replaced in favor of a better design), but pictured in white are our latest version of the Gen 1 gears, motor-axle adapter, and axle. These are printed in the PLA given to us in the box in which we received our 3d printer, and are made with just 20 percent lightning infill on the gears.
Our Gen 2 gears, motor-axle adapter, and axle are the ones that are approaching the level of what we are planning to actually use in our robot. As you can see the sizing completely changed. We are using much smaller teeth. In Gen 1 those 2 gears could only manage a 2:1 gear ratio, but now we have a 6:1 gear ratio with slightly smaller gears. Also, these are printed with PLA+ filament and 50% grid infill so they are much stronger and very high quality. Also, our motor-axle adapter is now tighter on the motor and has a smaller and sleeker design. Once again many of our failed or outdated prints are not shown.
In addition, you can see we set up 100% of our electronics. Just a single motor attached to a battery pack.