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Top Tip Tuesday
These tips were created by veteran FIRST® participants to further support UK teams. They are released weekly on Slack, but can also be found here in case you miss a week.
Preparing for judging
We hope you’re having a great half-term and getting some essential build time in! This week we’re touching upon judging at the regional events, to get you award-ready.
The regionals are about more than your robots, and judging is a great way to show off your hard work. Although it might sound intimidating, this is your team’s chance to showcase what you are great at!
When your judging session starts you will be asked to give a 5 minute presentation about your team. Use the opportunity to explain what you are most proud of from your project. This could be an awesome autonomous programme, a creative approach to building or your sterling efforts to encourage other teams. So how do you decide what to talk about?
Have a look at the award categories, your presentation is key to help judges decide on the worthy award winners. Try and focus on one or a few awards you think your team deserves to win and figure out the best way to explain to judges why you’re the most deserved to win those awards.
The judges will also be looking over your Engineering Notebook. With the event quickly approaching make sure your notebook is up to scratch. If there is something your team has done that isn’t documented in your notebook add it in!
As with our robot suggestions last week, make sure you prioritise which elements of the notebook that are the most important for your team. There’s lots more information about what should be included in the Engineering Notebook guide.
Refining your focus and competition strategy
Hi teams! As the competition draws near, it’s important to refine your focus and competition strategy. Look back on the priority list you made at the beginning of the season and decide which high priority projects you need to finish and others you will set aside. Consider how sidelining one project may have consequences on other projects that depend on it, eg cancelling an intake could impact an elevator project.
Be realistic when you weigh up how you will make it easier to complete your robot against how useful the robot will be when complete. You wouldn’t want it to be completely useless so make sure one ‘hero’ feature works well.
It’s also vital to begin preparing competition-specific tasks besides building. Check your robot is correctly wired, phones are paired and functioning, and your motors are working correctly. These pesky problems could easily threaten your championship experience – you’d be relieved to have these covered.
The robot programs should be designed and tested thoroughly before competition. Remember that each motor, servo and sensor on the robot does nothing unless the code knows what to do with it. Code to drive the robot is most important, as without it the robot is unable to move around the field.
If the robot can drive, one autonomous routine or more should be designed. There are scoring elements that can only be completed in strategy or are worth more if done during the autonomous period, so they are worth the effort.
That’s all for this week – have a good half-term when it begins!
Reflecting after your scrimmage event
Now scrimmages are finished, it’s important to reflect on what you learned. Experiences with other teams can help you understand the game, competition, and how to progress your robot for the regionals in March. Create time for your team to share interesting things they saw other teams do and any insight they gained. You can consider:
What did other teams do that you haven’t tried yet?
Was there an aspect of the competition you forgot about or a strategy you could build on?
Did you find a new way to perform an autonomous routine?
By considering these questions, you can focus on the most important aspects to work on for your team and robot.
There may be parts of the competition that you haven’t considered yet, such as the Engineering Notebook and community outreach, which are worth looking into.
The Engineering Notebook helps to preserve your team’s knowledge across the years your school competes and helps you present your work to others at the competition. You could try something as simple as writing down what you do at each team session or get each group to present their work in front of a camera.
It is also a good experience for the team to present to the local community, be that to their classmates or their community in an open viewing day. Remember what the FIRST acronym stands for (For the Inspiration and Recognition of Science and Technology) – you are being inspired by working in the program and you can pass the inspiration on to the community with just an hour of sharing!
Thanks for reading this week’s Top Tip!
This tip shares how to design an effective autonomous program.
It’s best to start by marking out a full-scale field on the floor with tape to give an indication of scale and location of the robot. Then, consider what you want the robot to do during the autonomous period. Consider critical locations and positions the robot must be at, such as the start position, manipulation points, and end position. Draw out a path you want your robot to follow using these points. Sensors can assist in helping to position the robot accurately at these points, but are difficult to program and occasionally hamper accuracy and consistency. The phone camera can be used as a sensor too, so if this interests you, it may be wise to mount the phone in a consistent way so the camera faces forward.
An important tip for this year’s game – Google has created a Tensorflow machine learning system that allows you to detect the Gold Sample in the Sample Field autonomous mission take a closer look. You can use the phone camera and google blockly coding system to deploy this code to your robot. Remember that if you choose to do this your location and positions depend on the random location of the Sample, leading to multiple situations to plan for before and after you try the mission.
On that line, remember that there are different locations depending on what position on the field you start at, and you must plan for all of them. The robot doesn’t have to detect its own position though – you can select which autonomous program to run.
Code the path piece by piece, making sure the robot consistently drives to the location you code it to before coding more. If you go in steps, you will create a more consistent and refined code all the way through, and it will minimise the effect of natural inconsistencies making large errors later on in the autonomous program.
Instead of a tip this week, let’s reiterate some checkpoints you’ve ideally reached before wrapping up for the holidays:
Drivetrain: Your drivetrain is built and driveable, meaning you have settled on a design and wheel organisation, and figured out the gear ratio you want to use.
Manipulators: You have final designs for each manipulator, and an idea of how to mount them onto the robot. You may have a functioning prototype built for each idea, to help you understand how you want to build each one with REV parts.
Programming: You have a fair grasp of the programming system, and have developed code for the drivetrain so that you can use it. You may have mapped out an autonomous program and begun coding it.
Electronics: The expansion hub is setup and paired, and all drivetrain motors are connected. You have a rudimentary understanding of the different sensors, and what will be needed for the manipulators.
Also, you have decided on a team name by this point. Be creative, and Merry Christmas!
Weighted Objectives Table
Weighted Objectives Table
This tip is a guide to run a successful Weighted Objectives Table meeting, which is an objective way to pick a design, making it fairer for the team. It doesn’t need to be concisely followed, but is recommended to give it go.
The meeting should be a full team discussion, where each group presents their ideas so far: how it works; problems you ran into and how you solved them. After presenting, you can clarify questions, concerns, comments and commandments. Check the proposed design follows the corresponding rules . Remember, the first concern should be objectively choosing the best design to fit the strategy and not surfacing opinions of the robot.
After all solutions for one priority have been shared, you move on to the weighted table. A more in-depth guide can be found in the mentor guide (pp. 21-22) and in the ‘Decision Making’ flowchart.
Discuss and decide five criteria you will assess the prototype on (robustness, simplicity, successfulness, etc.) and rate the importance of each of these on a scale
of one to 10. Simplicity should always be a criteria, and ranked as 10 for importance by rookie teams. Discuss each prototype and give it a ranking out of five for each criteria. Multiply the score of every criteria by its weight and add it together for each prototype. The one with the top score is objectively the best design. This process is then repeated for each different priority.
Once this is done, you have an idea of the prototypes you would like to pursue! You can then move on to creating these prototypes out of REV extrusion and working on integrating them together and into the robot.
This tip is about prototyping, or the process of generating ideas for solutions to a problem to testing and refining those ideas to make real solutions. It’s a large part of what you do as an engineer, and in life in general! Here are some pointers and tips that are useful when prototyping for a FIRST game:
It’s best to attack each aspect of the game in small groups. Working together, you can talk with one another to refine your ideas, and it means nobody can get carried away with their own idea and damage team cohesion. It’s also best to dedicate keep one group building the drivetrain, as it is must be built in order to test prototypes.
When generating ideas, there is no good, bad, easy or hard! Just figure out how you can achieve the task at hand. You’re building for one specific aspect of your priority list, so be careful when thinking about how multiple ideas can fit together before things have been agreed on.
After you’ve come up with a bunch of ideas for each aspect, narrow the ideas down to about three for each. Develop these further by thinking about important dimensions and frames.
Depending on the amount of time available, you can try and start to build each design with the REV system, being careful to not cut the extrusion at all, and not over tightening the bolts. Use this metal prototype to find out critical dimensions (how far apart the wheels should be, what height works best, how fast the motor should run, etc.) so that you could build a final design if you wanted to. Don’t forget to record these critical dimensions, as not only are they vital for later construction, but they are also great evidence of a strong engineering process.
Remember to consider the building constraints given in the manual, as the challenge video may not have specific rules about some important building constraints. This can cause redesigns or occasionally complete scrapping of the idea, so be careful!
General REV Parts
General REV Parts
This is a multi-layered tip about parts in your kit which you may not know about, and how you can use them to your advantage.
The first of these is the corner blocks (REV-41-1562). They are new products from REV this year which greatly simplify the building process when building frames. They are used much like other brackets, but you can secure three pieces of extrusion to three different sides of the block. This allows you to make a 90º 2D or 3D corner with just one corner cube instead of two or three plastic corner brackets. It is possible to replace the corner brackets in the drivetrain with this component, but if your drivetrain is stable enough already it’s not worth the hassle. However, using them to build frames to mount prototypes and designs onto the robot is worth taking advantage of. Just remember that some additional 45º support beams may be necessary to support the frame to ensure stability if it is big.
The second is the Linear Motion Kit (REV-45-1507) and the Pulleys sets and cord, which make up the Linear Motion System. This is the system that allows you to make sliding lifts and elevators. The guide to build one side of a lift can be found here, and it is worth a read if you need to lift things up very high. It’s almost always necessary to use both linear motion kits and build two sides for one lift, as the lift can become quite unstable at a high stage with just one side. Also make sure that the base stage is highly supported, as the lift can bend a lot when it is fully extended.
You can also use the pulleys with the polyurethane cord (REV-41-1164) to make conveyor belts and grippy rollers to intake objects. When you need a specific length of cord (and not the entire spool), you can cut the cord and use the included barbs (REV-41-1165) to create a smaller loop.
Finally, for those using chain, get to know how to use the chain breaker, one of the most important tools in the kit. It allows you to break and join chain at whatever length you want. You can find a guide for its usage here, though it’s important to point out that the usage of a master link is not strictly necessary unless the chain needs to be frequently removed, and it is difficult to access with the chain breaker.
Drivetrain: Gear vs Chain
Drivetrain: Gear vs Chain
This tip again concerns the drivetrain, and focuses on the connection between your motors and your wheels. Having the majority of your wheels powered maximises traction and agility, as it spreads the power from the motor over a larger contact area with the floor. This means that most drivetrains will have to power more than one wheel with just one motor. There are two ways to power multiple wheels using the REV build kit: gear-gear, or chain and sprocket. REV-made guides for how to build these shipped as part of the kit.
Gear-gear drivetrains rely on meshing between sets of gears in order to transmit the torque, or rotational force, of the motor to multiple sets of wheels. This system allows for lots of variability and easy build and maintenance, but it is bulky and any loss of the meshing between gears can lead to complete loss of power in a wheel.
Chain and sprocket drivetrains rely on a chain connected to sprockets (the gears with big teeth that are used with chain) to drive the wheels. Chain allows you to place your wheels anywhere, and over long distances it is much less bulky. However, you must use the right length of chain, and it requires constant maintenance to keep taut. If it becomes slack, it becomes difficult to manoeuvre the robot because the chain will start to skip.
There are benefits and drawbacks to both systems, and this tip compares some benefits and drawbacks of the two. For your team to make a decision, you must compare these two systems for your usage case. If you can’t decide, you can always try to build both.
Drivetrain: Dropped Wheels
Drivetrain: Dropped Wheels
This week’s tip is a drivetrain reminder. The FTC UK REV kit comes with adjustable motion brackets, which are the plastic plates with ridged backing that slot into one another.
If you are building a drivetrain with 6 or more wheels, your robot may initially have difficulty turning. This is because the front and rear wheels drag and cause friction with the floor, which makes your robot less maneuverable. If you use the variable motion bracket on the middle wheels and ‘drop’ the middle wheels lower than the other pairs, only four wheels will be in contact with the floor at a time, allowing you to turn with ease. Also, because one set of wheels will be raised slightly off the ground, it is easier to maneuver over terrain. However, your drivetrain will only have four wheels in contact with the floor at any time, and depending on the amount you drop the middle wheel, the robot can rock back and forth as you change direction. Consider the benefits and drawbacks of each drivetrain system, and thanks to REV’s building system, it’s easy to them out and see what works best!
This forum allows FTC participants to ask questions regarding this year’s game pertaining to subjects such as game rules, judging and robot inspection. It’s especially helpful to read questions and answers that have already been posted so your team stays up to date with the most recent game information.Access FTC Forum
Reddit and Discord
Reddit and Discord are forums for FTC participants to post and view helpful videos and information related to this year’s challenge. Teams may post information about what has worked or not worked for them during the build season.Access FTC Reddit
ROVER RUCKUS Season Materials
Keep up to date with the latest season materials on the FIRST® HQ website. Teams can access the most recent game manuals, DIY field guide, and inspection checklists.
Access ROVER RUCKUS Season Materials