Day #4 – 1/6/2015 – Automagical

Lab Opening Time: 9:20 AM

LOTS of work done today.

Today’s meeting was a vital point in this year’s overall season due to the final decisions made concerning the robot design and strategy. The day started with Mr.Black collecting the team together to articulate the importance of an engineering mindset: to be curious, to adapt, and to improve. He urged us to think about every detail, and to foresee what potential problems might spring from even the most minor of actions (a nut not tightened, a tiny piece of information forgotten from the schedule, leaving a door open).

Team meets to finalize ideas.
Team meets to finalize ideas.

To branch out from yesterday’s meeting, the team had concluded several strategies concerning robot design and human player actions that night. From those rough ideas, today the team’s main builders, thinkers, and leaders met together in the first hour of the meeting to conclude the thoughts of the last few days. It was decided that the team would begin prototyping, and began assigning people to each task as seen in the picture below.

The Team begins to assign tasks to individuals to being prototyping.
The Team begins to assign tasks to individuals to being prototyping.

During this meeting, students talked extensiveness on the mechanism behind holding onto a can when at the full six tote height and how one might keep a hold on a stack of totes while moving. There were many “rib” ideas, mechanisms that wrapped around the base of the can (because at this point you would only have about three inches of the can to hold onto), but there was also the “pulley” idea where two ropes would range from bottom to top of the robot to keep the totes moving vertically and not tip forward. This idea will be branched out into a prototype soon.

The first prototype of the day was a pushing mechanism based off the idea that if there ever was a need for a can or tote to be placed on a stack, that we would have the ability to do so. This was accomplished by two large pistons attached to a steel plate; this design was the initial idea, but the main problem was that the pistons were too heavy and the amount of air we needed to push a six tote stack was not that much. The idea was revised into a different system where two smaller pistons were zip-tied together and screwed into a wood plate. After testing this with several different tote sets, we found that this model was significantly more efficient than the first edition.

The outer frame is the 1st edition and the inner frame  is the 2nd edition of the pushing mechanism.
The outer frame is the 1st edition and the inner frame is the 2nd edition of the pushing mechanism.

Other mechanisms were given the “OKAY for prototyping  like the Autonomous “Can-Hook”  shown in the below video. This prototype is an autonomous strategy to grab the cans for latter use and to also drag them into the auto zone for points. This mechanism has two long arms, fairly light for their length, that hook under the rim of the can handles to be pulled into the alliance’s landfill/ auto area.

Another mechanism worked on today was the “Tote Rollers.” This prototype is based on tote alignment. The idea is two arms with two motors and wheels at the ends will spin the tote into alignment with the elevator. This is an important piece that might make or break a robots overall design: if we don’t have something to align the totes for us, we will probably never have the opportunity to pick up from the ground. This prototype was met with difficulties on all ends, in fact failure in some, due to electrical and mechanical errors. While the wheels were rolling by the end of the day, there was a major problem in the fact that the planetary motors attached at the ends of the arms were not strong enough to do anything to a tote. We learned from our failure and are continuing to work on fixing the overall design of this prototype.

The final prototype being worked on today is the elevator mechanism. The team had started work on this in the afternoon, and by the end of the day the prototype was well on it’s way. We’ll keep you updated on it’s progress and problems we faced.

In other parts of the team, Business had finally tackled an issue it had been dealing with for a while. The “books” of the overall balance of sales on Light bulbs, one of the fundraisers the team is doing, wasn’t weighed properly but after some investigation the books were settled! Now Business is working on the Chairman’s award and contacting new/old sponsors.

Throughout the day, people kept bumping into Mr. Black’s 1/72 scale Saturn V rocket model display case, causing the 1/72 scale German-made “Civilian Airport Personnel” figures to fall over.  We are happy to report, they have all been returned to standing position, and the Saturn V is cleared for launch.

NASA's "top men" clear the Saturn V rocket for launch on the Apollo 11 mission.  Circa 1969.
NASA’s “top men” clear the Saturn V rocket for launch on the Apollo 11 mission. Circa 1969.

In Leadership, an important schedule was made by Jack, the president, on the due dates of manufacturing. This is an important step in planning out the rest of the season as we hope to have a few days of drive practice before the robot has to get wrapped up and tied.

Jack makes a manufacturing schedule to keep the team on track.
Jack makes a manufacturing schedule to keep the team on track.

 

Additionally, Jack took inventory of the Kit of Parts and separated out the important items such as Product Donation Vouchers.

The design of the VEX swerve drive was drawn out in ExpoCAD, and then in Autodesk Inventor CAD from start to finish.  A picture of each is shown below:

ExpoCAD of VEX Swerve Drive
“Expo” CAD of VEX Swerve Drive

 

On the CAD side of things, Mr.Black and Cynthia, the leader of the CAD team, worked to properly configure Autodesk Vault for the 2015 season.  This proved to be a major undertaking, which needed several hours of attention, but in the end we set out to accomplish our goal of proper CAD data management.  The difficulty was in setting up the Vault Project File and working folders, which we still don’t entirely understand the inner-workings of, but it works properly for now.  Additionally, we activated a new feature on the Vault server (ADMS Console)  to “Track File Status”.  We initially had some concern about the Vault becoming “locked” from performing the “Update File Status” action, but experimentation on a test vault proved it to be a non-issue.  The new “Track File Status” feature will warn “User A” who has an assembly open if “User B” has checked in updates to components that are children of the assembly.

On design of the swerve module, the following determinations were made:

  1. The 50 tooth gear driving the wheel will hit the ramp in certain circumstances, producing an unfavorable condition.  Reducing the size of this gear increases the primary reduction ratio needed for the desired speed.  We attempted changing the 3×7/8″ colson wheel to a 3.25″ VersaWheel DT, but while the diameter fit, the width did not, by about 3/16″.  We did not want to modify the wheels in any way, so we decided to reduce the size of the gear.  While we discovered VexPro offers a 48T gear with the VersaKey pattern (they do not without the VersaKey), a 48T gear would still scrape the ramp when the robot is “sunk” into the carpet.
  2. We changed out the final drive gear to a 44T gear, which brought its own set of problems in that the Colson wheel would interfere with the bevel gear directly above it.  Fortunately, we were able to slide the Colson wheel over on it’s axle 1/8″ by removing a previously-designed-in spacer, providing adequate clearance between the wheel and all components in the region.  So, the wheel’s center plane in the axial direction is located 1/8″ away from the rotation axis of the swerve module.  We anticipate this will cause only a negligible effect on driving.
  3. The portion we formerly referred to as the “hat” is now being named the “tube”.  The “top hat” has yet to be designed.
  4. After discussing the possibility of the “tube” piece (upper bearing support) and the lower bearing blocks being made as one part that extends through the gear, it was determined that the bearing blocks should stay separate pieces, for simplicity in the machining process.
  5. The “tube” will be extended upward to near the height of the top steering miter gear support bearings, to reduce the height of the top-hat and reduce complexity of machining of the top-hat.
  6. The tube piece will actually be made from thick-walled aluminum tube (3.5″ OD, 2.5″ ID) rather than from solid bar stock.  This reduces machining time.  McMaster is the only vendor we’ve found of aluminum tube in this size.
  7. We discussed and debated how to constrain the module from dropping out the bottom of the static-mounted plate.  Mr. Widholm made a proposal to add another plate with a circular-profile groove underneath the gear, and another circular profile groove in the bottom side of the large 84T steering gear.  We determined that to maximize efficiency in our manufacturing production schedule, we’d rather place four radial bearings on shoulder bolts on the top side of the static-mounted plate.
  8. We want to place material back into the center of the previously-designed lightening pockets in the tube, to support the radial bearings on the shoulder bolts discussed above.  The other two radial bearings will be supported by the 30T gear axle, with the shoulder bolts threading into 10-32 tapped holes in that axle.
  9. We determined that we should build 6 complete swerve modules.  Four for the robot, and two spares / demo units.  Due to the cost involved, we will not purchase a VersaPlanetary gearbox and Mini-CIM for one of the spare units.
  10. We determined the electronics mounting area in between the swerve modules may not be as spacious as previously anticipated due to the lay-down nature of the VersaPlanetary gearbox.
  11. As we were closing for the night, and discussing the chassis layout, we realized that the two static-mounted plates for each swerve module would need two different versions.  The full assemblies on opposite corners would be identical.  The geometry of the plate in the horizontal plane is the same, but vertical axis features will likely be different between each pair of modules, requiring different CAM programming.

A final picture of our design whiteboard before closing time, featuring our “ExpoCAD” of the robot for the day is shown below:

Design whiteboard showing ExpoCAD and goals progress as of end of Day 4.
Design whiteboard showing ExpoCAD and goals progress as of end of Day 4.

Lab Closing Time: 7:00 PM

 

 

Day #3 – 1/5/2015 – Noodleing Around

Lab opening time: 10:07 AM

Today started out with the team setting goals for what needed to be done today. Our goals for today were:

  • Check the practicality of the swerve drive
  • Start on VEX Pro order
  • Check the Versa Planetary Inventory
  • Create the “expo” CAD of the robot
  • Check the Kit of Parts Inventory
  • Start on FIRST Choice order
  • Revise build blog
  • Start on VEX swerve drive

After setting our goals, the build team began discussing what robot systems and functions we needed to start working on. We came up with:

  • Swerve Modules
  • Elevator
    • Forks
    • Static Frame
    • Tote System
      • Fork Clamp
      • Ejector
    • Recycle Can System
      • Grabber Pneumatic
      • Carriage
  • Frame
    • Intake Rollers
      • Versa Planetary
    • Electronics
    • Pneumatics
  • Autocanner
    • Possibly hooks
    • Possibly actuators

After breaking up the robot into different systems, five different teams were created to tackle separate projects. Joshua, Alexander Luke, and James worked on the “expo” CAD of the robot. Mika, Olivia, and Claire worked on the tote-can elevator,  Bhavin and Roupen worked on the intake rollers that will help guide the tote into the robot in the correct orientation. Lastly, Devon, Lousaper, Elizabeth, and Meet worked on the auto canner which is basically a mechanism that will grab the two recycling cans during the autonomous period.

Roupen and Bhavin work on the intake rollers.
Roupen and Bhavin work on the intake rollers.

The team expanded on the elevator idea that they had yesterday which was to have two different stages on our elevator, one that would lift the totes and one to hold the recycling can. On further discussion, some member realized that the same effect could be done by putting on doors at the front of the elevator that would keep the can from falling out. However, Mr. Black thought that the doors would not be much more effective because they would still need motors and gears and the difference between the doors and the two stages was not very big.

Testing the design for the autocanner.
Testing the design for the autocanner.

Late in the afternoon, after one of the elevator ratcheting prototypes was completed, several members of the team got into a discussion about making an  elevator that would have more torque at the bottom and more speed at the top. They realized that they would need some sort of pulley system that would increase the diameter of the bottom pulley as the elevator comes down. The member soon began to wonder how many rotations it would take to wind up rope on a pulley given that the length of the rope was 72 inches. After coming up with a mathematical equation, several members tried to solve this problem by hand. Mr. Black was convinced that a problem of this complexity would only take about 20 lines of code in Basic. After many more attempts on paper, Mr. Black decided to solve this problem using excel. For those of you playing at home, the answer to this question is approximately 10.9 rotations.

Math equation
Math equation
Jack and Elizabeth work on the math for the pulley system.
Jack and Elizabeth work on the math for the pulley system.

2015_varianle_winch_calc

While work continued on the prototype, the CAD team worked on a prototype of the swerve drive for the programming team to practice with.They also worked on the CAD model of the elevator.

Cynthia working on swerve module.
Cynthia working on swerve module.

The business team was hard at work today. They were able to organize the business cabinet, print the team 696 brochure, and write more sponsorship letters. Late in the afternoon, more discussion began on whether or not to place the recycling can on top of the totes before stacking the totes or to place the can on top of an already existing stack.

The team decided that it would be best to start with the can and then build a stack because the robot would not run the risk of knocking down the stack when trying to place the can on top of the totes. Finally, near closing time, after members started to experiment with the human player station and the advantages or disadvantages of placing the can on its side rather than vertical. Once four totes were stacked, we realized that the can was at the same height as the litter chute. This meant that we did not have to try and feed the noodle into the can from the ground but could instead just be pushed into the container from standing height. After many trials and a few looks at the rules, we came up with a strategy for placing the pool noodles into the can.

 

Lab closing time: 8:15 PM

After Dark CAD Club – Meeting #2

In preparation for the VEX Pro order, I began to lay out the configuration of the CIM motor and VersaPlanetary in concept.  Much of it is just free-handed into place in this model currently.

Mini_CIM+VP_ISO

Mini_CIM_Side_Clearance

I wasn’t too fond of how far the VersaPlanetary sticks up, nor the belt routing around the VP for the CIM, nor the mounting of the VP.  So I got to thinking, could it lay down, with another pair of miter gears to transmit the power to the steering pinion.

Right_Angle_Drive

I need someone to do a sanity check on all this first thing in the morning, and we need to get the order in ASAP.  This is going to be yet another expensive year.  Definitely no room in the budget to build two robots worth of this.

Day #2 – 1/4/2015 – Co-opapotamus

Lab Opening Time:  2:00 pm

Going off of yesterday’s goals, the team had high expectations of what we needed to do today. To recap, our goals included an “expo” CAD model, a clear and well thought out strategy of how to play Recyle Rush, and the mechanisms to do so.

The math and physics roughly sketched on the whiteboard
The game’s math and physics roughly sketched on the whiteboard

We started in the lab at 2pm and began work on strategy almost immediately. After yesterday’s reveal, everyone had gone home to study up on the game in preparation for Mr. Hoard’s, the business mentor, game “You Don’t Know What You Don’t Know” but we’ll talk about that later.

Each Subdivision had important jobs right off the bat for this season. Today, Business worked on the Chairman’s award along with the writing for the Kickstarter which will be up soon.

A CAD member (or my partner in Crime, Olivia) helps to finish the field.
A CAM member (or my partner in Crime, Olivia) helps to finish the field.

The Prototyping Team, along with the help of the CAM (Computer Aided Manufacturing) Team and a few CAD (Computer Aided Design, if you didn’t know what these acronyms mean) members, helped continue set up for the game field.

 

On the Programming side, members began research on encoders for a swerve-drive mechanism ,and continued work on a FRC simulator which would simulate robots that would run the code the programming team is working on.

A programmer's joy after his program works.
A programmer’s joy after his program works.

The 3D printing members were not idle either, they were printing prototype parts for possible mechanisms and also worked on  a few side projects that occur on and off season. (Thanks for the title, Sipan ).

Cynthia, the Leader of the CAD team, worked on the swerve drive (as Mr. Black has shown in his previous post about his midnight CAD Club), and props to her for the amazing mechanics going into her design!

Animation was working on metallic surfaces for this years robot animation along with rendering past season animations.

Strategy meeting discussing field dynamics.
Strategy meeting discussing field dynamics.

Now, to the team we’ve all been waiting for: Strategy! Less of a team and more of a huge glob of people, the strategy team worked hard on game dynamics and mechanism. Today, hours were spent on the overall strategy that the team wanted to accomplish this season. Recycle Rush proposes a challenge in that it requires several different mechanisms to do certain tasks. “How many yellow totes should we aim for?“, “What mechanism should we use for the green recycling bins, and can we use that same mechanism for totes?“, all of which were important questions discussed thoroughly today.  The team regularly migrated from the computer lab, to the shop floor, and to a white board.

Strategy Team camps out in chairs to talk about game physics.
Strategy Team camps out in chairs to talk about game physics.

The Team’s goals today were to make an “expo” CAD model (half credit), and  a well thought out strategy to go hand-in-hand with smart mechanisms (three-quarter credit). While we reached our main goals and mech for the autonomous period, the team still needs to think about the strategy for the teleop period which is a completely different ballgame.

Lab Closing Time:  8:15pm

After-Dark CAD Club – Meeting #1

After getting home, I couldn’t help but try out this concept in Inventor.  I just had to know if it worked. After 6 hours in CAD (now at 1:45 AM after kickoff day), I think it’s working, and we can finish the model and produce this.  Definitely some fun machining involved, but more design work to do first.  I’ll let the students take it from here.  Large steering gear is 84T.  Drive gearing is 30:50.  Wheel is 3 inch diameter.

Swerve_1-3-15

 

 

 

Day #1 – 1/3/2015 – Kickoff

Lab opening time: 7:00am

Team 696 arrived at the engineering lab bright and early to watch the live webcast of the 2015 FRC Kickoff. With the limited space in the robotics lab, some of the team went down to the downstairs engineering room.  After the reveal of the 2015 game, Recycle Rush, all members of the team took time to read over the game manual, discuss the rules, and talk about strategies. Some of the strategies and questions that were asked were:

Is it better to place the litter on top of the recycle bin or to place the litter inside of the bin?

Dose it matter whether the litter is placed inside the bin before the bin is placed on top of the totes?

Which is the best scoring station to stack totes on?

Brainstorming!!!
Brainstorming!!!

We then moved on to what we wanted our robot to be able to do and what a winning robot would be able to accomplish. After a team-wide design meeting, we had two basic strategies for the autonomous period: the first was to grab the two center green bins from the step in the center of the field and bring those back into the auto zone and have another alliance partner push the last recycle bin into the auto zone for eight points. The other option was to stack all of the yellow totes and bring those into the auto zone. This option allows us to get twenty points and give us easy access to the step to get the coopertition points.

Strategy discussion
Strategy discussion.

During the teleoperated period, one strategy is to pick up the two bins in the landfill and then the two bins of the same orientation and so on down the step and then place those two stacks of four onto the scoring zone. Another option is that we pick up a recycle bin and two or three totes and place them on an already existing stack. The team all seems to be in agreement that getting the recycle bins is crucial because there is a limited amount and adding a bin on top of a stack triples the score of the stack. Additionally, we thought that we could use the litter chute to place the litter into the recycle bins so that we would not have to build another mechanism for the litter.

However, the design is still in its early stages and we are still researching how to keep the recycle bin stable on top of the totes and how to be able to lift up the recycle bin and totes without having to build two different mechanisms.

On the design side, the CAD group began research and modeling of team 696’s first swerve module.

Working on the swerve drive.
Working on the swerve drive design.

Work also began on the construction of the field. During the strategizing meeting, a question was brought up on whether or not two totes could be stacked on each other from the tote chute. After testing several times and several different ways, we have established that the box usually falls on its face and is not in position to be stacked.

Claire and Alfredo building the step
Claire and Alfredo building the step.

Our goal for tomorrow is to have a clear idea of how to play Recycle Rush, an idea of what our mechanism will look like and to have a completed “expo” CAD model.

Lab closing time: 5:30pm