Week 4 5 i dont even know anymore
It’s been a while, hasn’t it? By necessity, a big update this time around.
Mechanical
As it turns out, mechanical are goats and can somehow handle goofy cadathon parts.
We’ve mostly finished the parts for the robot, and are moving on to some other projects, such as fabricating parts for our new robot cart and battery box.
We’ve been fabricating spare assembly parts for things such as arm and gearbox. CAD designed a lovely frictional brake system (for some reason) and fabrication for it has been rather interesting as they’re decently low tolerance parts. We are also working on making belt tensioners using out cnc and mills. Besides that we are also working on redesigned parts since cad loves to remake things 500 times. We are also doing updates on our machines by fitting a dro on one of our mills. We are also working on fabricating and assembling a proper robot cart instead of using a random cart. That’s mostly done and just needs a few more rails with thousands of holes. Battery box is also on the way and no more floor batteries or traveling with a battery buddy to comp.
Assembly
We powdercoated our chassis and spray painted some parts. It’s nice, although working around the extra thickness added has proved to be a bit of a pain.
We also put all our v1 assemblies onto the chassis. It’s finally coming together
After assembling our v1 gearbox, we found a couple problems such as tolerance buildup between the gearbox plates and chassis. Some filing took care of the problem though. When assembling our cable runs to actuate the intake, we realized that we had to loop our metal cable around more than once to have more than 180* of rotation, but we didn’t have enough space to, so we decided to switch to long tensioned 9mm HTD belts since they were easier to assemble and fix.
We also disassembled our swerve modules and found that most of our bearings were starting to go bad, so we would probably have to reassemble the modules after our first competition.
Electronics & Pneumatics
With the chassis powercoated and the swerve modules assembled onto it, we were able to start the integration of electrical components onto the robot underbelly. We were able to assemble our subplates onto the drive train with the components on them already, allowing for the process to be quicker and reduce the amount of time we need to finish everything. We had to do the subplates on the drive train as it would allow for the mounting of the components to be more secured, and our mentor pointed out that it would allow for maintenance to be easier. Hopefully by next week, we are able to finish securing components down and start testing by then.
Recently, our subteam was able to mount all of our plexi plates with the electronics components onto the underbelly of the robot and the pneumatics on the top of the robot. Considering our team’s past with wire management, we wanted to prioritize the ability to maintain and replace components. Therefore, our wiring has changed to allow for the viewer to see all the components, use cable flags so that we know what wire is going to what component, and a ton more zip ties and anchors to ensure no loose wire is present.
Programming
As the bot is being assembled we slow down for what we can test on the robot. One thing we have been able to make progress in is in our intake. First, we tested the auto intake and auto outtake commands that use a rev color sensor to determine the series of intake movements to successfully capture a game piece.
Currently in development is tying field orientation to the dpad to ensure faster cycle times. We plan on having the four cardinal directions tied to the dpad that will send the robot to that direction using the shortest path. This will be overridden when moving the right stick so that the driver can quickly switch between automated and manual control of the robot’s rotation.
Another wacky thing that the prog team is working on is to create the ability to switch to arm centric drive, which is where the robot will rotate on the location of the wrist as opposed to the robot’s center. This could help with cycle time and node placement though this is highly experimental and is likely not going to be ready for the first competition .
CAD
We’ve been done for a while here and yet i still manage to be very late on oa
Even so, we’re working on some extra things - such as mounting cameras and swerve module covers - and refining our intake. Not much to speak of at the moment.
During assembly of the arm, we found that using steel wire rope to drive our joints raises a host of issues. It’s not really flexible enough, and thus working with it is difficult. Additionally, the wire rope that drives the wrist only has 180deg of motion. Compounding this 180deg of motion over three joints led to the wrist being practically impossible to have any range of motion, thus we transitioned to using 9mm wide HTD belt.
To extend on that, we are transitioning to using dyneema for driving the far arm. Dyneema is similar in strength to wire rope, yet many times more flexible, and thus much easier to work with. It adds some concern with stretching of the rope, but this is mostly mitigated by a custom inline tensioner system.
We’re behind on our personal schedule even though we’re the furthest ahead we’ve ever been. It’s quite a strange irony.
Post written by Chanon, Ian, William, Diego, and Ben.
