ausTIN CANs 2158 | 2023 Build Blog

[AndrewI]

Welcome to the ausTIN CAN’s 2023 build blog. It is my third year of writing down our teams progress through out the build season(2020 Build Blog, 2022 Build Blog). I plan on posting daily recaps which will include progress photos, prototyping videos, strategy discussion and progress reports. Our team’s goal is to make it to District Champs and onto Worlds. Our team consists of ~50 students and 9 mentors.

Its the final day before kick off. If you’d like to catch up on what we’ve been doing in the off season you can find that starting here. Tomorrow our team will gather in our lab and execute on our kick off plan. We have two other items that we plan to use, if the game allows it we are planning on running a swerve drive base with MKi4’s, or a fall back 6 wheel west coast drive. Both of these can be found at our Season Resources page.

Looking back at our previous year’s progress having a drive base with electronics all set, and driving will hopefully put us ~1 week ahead of previous years. We plan on using the assembled swerve drive base as our practice bot.

Season

Our team will be competing at the following events:

• Week One FIT District Waco Event
• Week Four FIT District Houston Event
• Week Six FIRST In Texas District Championship(If we advance)

In our opinion we got a great schedule of events this year, we have a decent amount of time between our events. This will allow us time to iterate on our robot between events.

Team Links

• Website
• Instagram
• Github
• 2022 Off Season Software Release
• 2022 Build Blog
• 2020 Build Blog

[AndrewI]

Day One, Kick Off!

Day one was a blast, I personally think this will be a great game. Our team has mixed feelings, and chiefdelphi is about 60% thinking the game is meh. I love the game because its not a shooting game and it doesn’t have climbing. Not a very high bar, but its a great change of pace.

First Impressions:

• The field is very open and I like this. It makes it harder to play good/effective defense.
• The cycle distance is very far. You have to run the full length of the field to grab a game piece and again to score it.
• The game isn’t swerve hostile out of the gate. We have some things we need to figure out before we know if we can run swerve or not(tomorrow’s problem). This excites us because we’d love to run our new swerve drive.
• Cones look hard to pick up.
• Sight lines from all driver stations are unobstructed. This makes the game amazing to play for the drive team.
• A kit bot can score pieces, and play the end game with nothing extra added!!

Our kick off went according to plan, so we ended for the day after we had a team discussion about each group’s scoring analysis. It feels a little odd not diving into what our robot must do, but I like this change. At my day job(I don’t get paid to do FRC yet…) we’ve been pushing choices off a lot until we learn more information about the problem and the solutions and that has been incredibly helpful. I think this approach will work wonders for this year. We currently don’t know a few things:

• How hard it is to intake cones. They can be ~4 unique positions and that makes intaking them hard.
• How hard it is to be DOCK and ENGAGED with two robots on the CHARGING STATION during end game. Is it worth figuring out a way to guarantee being ENGAGED? And is it worth the extra points?
• Can a cone mechanism also pick up cubes?
• How do cones fall out of the portal?

We need to figure out these questions before we can solidify our list of what the robot must do, could do, and won’t do.

Scoring Analysis

This activity went well this year, the updated template was a success. Most of the groups used the template to do their calculations. We learned a few things from the scoring analysis:

• Docking in auto is great points, however only one robot can dock so back up auto plans will be needed.
• The difference in points between high and mid scoring locations isn’t that high at 2 points per cycle. This makes it hard to justify the added complexity.
• A team could get away with only being able to score cubes or cones. Again this makes it hard to justify the added complexity of doing both.
• The SUSTAINABILITY RP is very hard to solo.
• The ACTIVATION RP is impossible to do with only one robot, but what if you drag a partner along?

Tomorrow our team takes a look at making a first pass on our robot’s must do, could do, and won’t do list. We also are planning on starting prototyping, field build and anything else we can think of!

[AndrewI]

Day Two

Today was the second day in our kick off journey, to start the day we got our whole team together and discussed what our robot must do, could do, and won’t do. After an hour of back and forth we come up with this preliminary list. The placement of actions on this list is not final, items will move around as we learn more information(from prototyping, outside sources, etc…) Also this list is not ranked/ordered in any way.

Must Do

• Get Mobility Points in auto
• Never Die on Field
• Never Tip
• Score Preload in Auto
• Retract Intake So We Don’t Get G204’s
• Floor Cone Intake
• Move Sideways
• Dock and Engage in Auto and Teleop
• Score Cones High + Mid + Low in Teleop
• Push Cubes to Low
• Scoring Alignment Assist
• Buddy Dock and Engagement
• Not Get Stuck

Could Do

• Floor Cube Intake
  • If we do Floor Cube Intake We must
  • Score Cube High and Mid
  • Be Gentle With Cubes(Don’t Pop)
• Automated Scoring Alignment
• Teleop Docking Engage assistance
• Score additional game pieces in auto

Won’t Do

• YEEEEET (Shoot Cubes)
• Have a mechanism that prevents us from getting pushed

This discussion also resulted list of questions that we want to find the answers to. These answers will possibly move items around the above list.

• Look at slider position relative to goals
• Figure out how hard it is to dock and engage on the charge station with another robot. Now make the other driver nervous and under time pressure. How hard is it?
• Understand the durability of a cube
• How to intake cones
• How well does our swerve drive base go up a charge station?

In addition to this list of things to figure out we also identified the next tasks, starting on the field build and brainstorming how to solve actions on our must do list.

After we finished our lists we let the students decide if they wanted to opt into continuing brainstorming/prototyping or go to their departments and start work there.

This allowed us to start building two wooden outer grids, and one coop grid. We are also planning on building the field(metal and poly carbonate) version of the charging station. This didn’t get started today, but we looked at the material list and made a shopping list.

Organized Chaos?

Brainstorming

To start the brainstorming session we gathered into small groups and then assigned which tasks each group was responsible for brainstorming ideas on. Then each group found different ideas and created a power point slide to share with the entire group.

We used the ideas presented by the groups to come up with a list of different ways to solve actions. Then we reformed into larger groups to start prototyping. We had one group focus on overhead roller cone intake, another group focus on vertical roller intake, and the last group focus on buddy docking and engaging.

Prototyping

First thing we did to prototype was trying to intake cubes and cones with our 2022 robot. This worked better than expected.

Good Intake

Sharp Makes Cube Sad

Well it worked better than expected until we tried to shoot the cube for the second time and cut the poor cube open in two spots. There is a vex double pulley on the cargo delivery subsystem of the 2022 robot, these flanges are a little too sharp for the cubes. I guess we know more about cube durability now!

The horizontal rollers didn’t work as well for the cones. The compliant wheels had enough grip but the current configuration doesn’t connect with the cone geometry well.

We managed to start putting together a few different intake prototypes but only had time to test the vertical roller intake today. The prototype was tested on cones and cubes with out any reconfiguration.

A Very Inflated Cube

MKi4 Swerve Testing

The next item we tested was the ability of our MKi4 drive base to drive up a 15° incline, a stand in for a tilted charge station.

Our swerve drive test bed is a 24″ square currently with out any bumpers. The first two tests we drove up and then let off the controls, the drive motors were in coast mode.

First Test

With Added Weight

We changed the drive motors to brake mode and tried again, this was better but we still slide down. The next thing we tried was turning the wheels 90°.

Brake Mode

90 Degree

With the wheels turned 90° the robot didn’t slide down the ramp. We even tried pushing it and it took a surprising amount of force to get it to move. The test bed currently doesn’t weigh a lot, adding weight should increase the traction. Hopefully we don’t have create any center of gravity problems.

Our next meeting is on Tuesday, we are ordering more metal, poly carbonate and will hopefully make progress on the wooden grids before then.

[veg]

Thanks for sharing these videos! Can I assume that you are using the standard black neoprene treads?

[AndrewI]

@veg

Can I assume that you are using the standard black neoprene treads?

Correct we are using black neoprene tread.

[pntbll1313]

Have you tried driving up the steeper 34.25deg incline that the bridge will be in until it begins to tilt down?

[AndrewI]

We haven’t yet but we plan on it. On Tuesday I’ll make sure to grab a video of driving up 34.25 degree incline with poly carbonate.
We are also building the field version(metal and poly carbonate) of the charging station but it is going to take us around a week to complete it. We’ll make sure to post videos of us driving on it once done.

[AndrewI]

Here is how our MK4i drive base handled the 34.5 degree incline today. The line on the poly carbonate is ~16" from the bottom that is around where the flat part of the charge station would begin. The drive base is missing bumpers, its on our list of stuff to add so we can test the interaction.

We did a bunch more stuff today, I’ll be writing up the full day’s recap tomorrow morning.

[AndrewI]

Day Four, First Team Recap

Every week on Tuesday we start off with a team recap, where each sub team lead presents what was worked on the previous week. You can find our recap slides here.

Field Build

The assembly of the first grid started today. We have revised our timeline of assembly, we aim to the alliance grid completed by Saturday. Today our new laser diode for our fiber laser arrived. We successfully cut 1/8″ aluminum as a test to see if we are be able use the fiber laser for the charging station parts. Yesterday we figured out how to flatten the field parts from Onshape and export them to a .dxf.

Our sheet metal brake isn’t rated for some of the longer bends at 1/8″ aluminum so we will be adding some relief slots along the bend line which will make the bend easier. The timeline for completion of the full charge station is being revised to having it done two weeks from now. The initial estimate of a week was far too optimistic for the amount of work it is to build the charging station. I really need to start doubling my original time estimates.

Prototyping

Today our prototyping groups regrouped and split into three refocused groups, intake, buddy climb, and arm. The buddy climb got right into work by having a mentor sit on our swerve drive robot? Wait what? I don’t recommend sitting on a robot, lets keep this to a stupid mentor trick.

It was a simple and quick way to add 180 lbs to the swerve buddy climb test. On the far side of the robot are two forks which are holding up our kit bot. We wanted to know if we would be able to drive up the 15 degree charging station with the additional weight.

Cone prototyping continued to find a bunch of different things that don’t work well for intaking cones on the floor. We tried a bunch of different configurations of wheels and compression with an overhead roller. The big 8.5″ grey wheel put a few cuts into the cone.

With out much success on our single overhead roller we assembled a version of a top and bottom roller we found from Ri3D Redux Team. This worked better, but we haven’t figured out a good way to index or control the cone once its in the robot. This prototype had the added bonus of working with the cube.

The arm prototype group started their prototyping journey with some sketches in CAD. These were used to prove that the geometry of an multi jointed arm would be able to reach the scoring areas and fit inside the robot’s frame perimeter. Then they used these sketches to make parts for a wood prototype which will be cut on the CNC router.

Driver Practice

Tonight was our first build season driver practice session, also the first real practice session with our swerve drive base. Back in November I talked about our driver practice plan, which if all goes well we aim to hit 100 hours of drive practice by Worlds. We had a small problem at the start, our swerve drive base still didn’t have any bumpers, enter some pool noodles and duct tape and we have some quick protection.

Today’s session was trying to get our drivers more familiar with swerve and how to drive it well. We did two courses today, a figure eight and a square with a plus(see the below gif). We are trying to encourage the drivers to think more like swerve and less like tank drive.

[AndrewI]

Day Five

The day started by reviewing our Must Do, Could, and Won’t Do list. We added one item to the could do list. We must signal to the human player which game piece to introduce to the field. I think we should add a speaker to the robot and play a happy noise if the human player enters the correct game piece quick enough and a sad noise if they enter the wrong one or distracted.

Prototyping

Overnight we printed a big 10″ TPU flexible wheel to try and test with the cone. The thought was a big wheel would be able to compress more and intake a cone from the square side or narrow end. What we experienced was that the TPU doesn’t have enough grip to pull the cone in. It is possible to increase the grip by adding double sided tape, but we’ve set this prototype aside for now.

We were inspired by Team 4481’s weed wacker concept and attempted to iterate on it today. They have a passive bar to stand the cone up afterwards, we aren’t interested in standing the cone up so we skipped that part. A single weed wacker kind of worked for us. Looking back at this we were testing on concrete and not field carpet so that might have been a problem.

Inspired by the decent performance of this we added another weed wacker and shortened the length of tread. This was the most promising results we’ve had so far. The cone was ending up mostly centered and facing the same direction.

After inspecting the cone and the prototype we noticed the base of the cone actually hits the hub of each weed wacker. So we’d like to try spacing them further apart and adding longer tread to increase the reach. If that goes well this prototype might get further refined.

Field Build

Today one of the cone sections of the grid was finished! The remaining 2 x 4 pieces were cut and organized. They are waiting on the final router pieces to get cut to be able to finish the entire alliance grid.

[Nick.kremer]

That weed wacker intake looks great. May I also suggest some angled plates just behind the spinners to further help funnel the cone to the center? Even some cardboard should do the trick.

Keep up the good work!

[Justin_Foss]

Happy to see the weed wacker concept taking its next steps, talk about the spread of OA and collaborative prototyping as a community. Inspired by your dual axis option, we’ll take another look at this tonight.

[AndrewI]

I’ll add this to the list of things to try tonight with it!

[Hadi379]

What happens if the tip of the cone is pointing towards the intake? And are both weed whackers spinning in the same direction?

[AndrewI]

Does this gif answer your question? If not I can try to get a better angle tonight.
The weed wackers are spinning in opposite directions.

[Takanori]

Do y’all think the results would change by a significant amount if the robot had bumpers on during this test?

[Nick.kremer]

A few more things that would be interesting to see:

• Intaking a cone standing upright
• Intaking a cube
• Move the chassis (aka dolly) much faster into the game pieces
• Intaking when a game pieces is up against a wall

[KaiFrc]

This looks amazing! Does the weed wacker also suck in cubes as well? I know that the base of the cube is around the same size as the base of the cone, so I’m wondering.

[AndrewI]

Day 6 Prototyping and Testing

It was a day dedicated to testing and assembly of prototypes! Which is great because that means we are learning what works and what doesn’t work. Today we assembled the 2 jointed arm prototype to prove that the geometry works. It is just able to reach the high goal it will get a little longer reach to more easily reach the high goal.

Low Goal

Mid Goal

High Goal

Inside Robot

Next we spent more time testing the weed wackers. One thing we observed with the weed wackers was the speed the chassis is moving relative to the speed the weed wackers are spinning matters a lot. If the chassis is moving too quickly the cone doesn’t get enough hits to center or end up in the correct orientation.

Chassis Too Fast

Next we tested up right cones. This didn’t work great most of the work was done by the wood center beam. If we used this idea we’d have to have a passive bar ahead of the weed wackers to knock over the cones.

We also tested the cone against the field wall to see if we’d be able to intake it still. This worked better than expected the weed wackers were almost able to get the upright cones even. Once again chassis speed played a big role, if pushed too quickly the cone doesn’t end up in a repeatable location.

Probably Too Fast Here

To end the testing before we started trying to improve them we tested weed wackers with the cube. The results from this really surprised me. I’d expect the weed wacker to knock the cube away. But instead it pulled them into the center.

After the marathon of testing the weed wackers we set out to improve them. A basic cardboard funnel is being created and we are increasing the distance between the two axis’s.

Another group started creating dual overhead rollers to test intaking of cones. After quickly clamping the prototype to a dolly we started testing the cones in different orientations.

After a few tests we noticed a failure to grab the cones sometimes. We ended up lowering the prototype so it was closer to the ground, this fixed the problem. The prototype handles the worse case of the edge of the cone being perpendicular to the overhead rollers amazingly.

In the current configuration this prototype doesn’t work with cubes. There isn’t enough compression between the two rollers. We will be increasing the compression and testing again on Saturday.

This prototype worked amazingly well. It isn’t as sensitive to the chassis speed. It does however leave the cones facing front or back and any where along the length of the intake rollers.

Two Possible Cone Locations

In order to score the cone we need to put the bottom hole side of the cone onto the pole. With a single additional powered point of rotation on the dual over head rollers we can get the cone facing in a direction that allows us to score it.

Cone Rotated

The other problem to solve is how to handle the unknown position of the cone along the length of the rollers. The current plan is to add time of flight sensors used to detect which way the cone is facing and the location of the cone. With the location and direction of the cone we can construct an offset to add to the robot’s pose(gathered from april tags or reflective tape) that will allow us to place the cone on the pole. The other thing that makes this possible is doing swerve drive, the robot can easily move in any direction and move to the required pose to score. For the first time in a while we are creating problems for software to solve instead of solving them other ways.

The current plan requires the dual overhead rollers to be placed on the arm. This will be an engineering challenge to make them robust and light enough. There also might be a way to make it work with out having the intake on the arm, we’ll investigate this idea more at our next meeting. Our next meeting is on Saturday we hope to finish out the alliance grid, start cutting charge stations parts, more testing and prototyping.

[Ry3512]

What are the dimensions between the two spinners? We are trying to replicate this prototype and have it orient the cones the same way.