VEX Robotics Competition or VRC
Season 2023/2024:

How to start a competitive VRC team?

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Step 1: Read the Code of Conduct and the Student-Centered policy. This applies not only to members of the team, coaches, mentors,  but also parents and anyone who enters a competition in-person or online. 

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Step 2: What resources do you need?

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• A VRC competition kit VEX v5 to build a robot, you can find this at vexrobotics.com. There is a starter and a super kit. The main difference is number of smart motors, super kits come with 8 11W smart motors instead of 4 11W motors, a vision sensor and 4 bumper switches instead of 2. Other sensors like distance, optical, inertial, rotation GPS sensor need to be ordered separate. A vision sensor can see up to 7 colors at once, identifies the location of the color tracked with X and Y coordinates and has built in WiFi radio. There are no small 5.5W EXP smart motors in the kits. 

• Access to a VRC field with the current game, Over Under for 2023/2024 and a Smart Field Controller to simulate competitions.

• Minimum 1 adult, who will act as the responsible adult at any competition. This person does not need to be the coach or the admin, but needs to be familiar with the logistics of the competition and the 2 policies mentioned in step 1.

• Recommended 5 to 7 team members.

• Access to a laptop or tablet with internet, to program the remote control, the autonomous part of the Head-to-Head matches and the autonomous skills runs.

• An admin person who will register the team, and sign-up for competitions. This does not have to be the coach or responsible adult at the competitions. This person will also upload the engineering notebook and provide the team with the key for the virtual skills challenge. 

• A season schedule, based on the team's goal, and a budget to cover the registration and travel costs, with transportation large enough to take both the robot and the tools to competition. 

• Download the VRC hub on a mobile phone. The drive team can use this to reference any rules in the game manual at a competition with the referee. This app also has a calculator to see how the game is scored and a timer for the different parts of the competition. 

• A paper engineering notebook or a digital engineering notebook. If the team uses a digital notebook print the pages as you go and store them in a binded folder. Some competitions prefer a physical copy instead of a digital link. If you use a paper engineering notebook, you might need to take pictures of every page and upload it to a link, in case a competition only accepts digital copies. 

• Plenty of space to setup the 12feet by 12feet. For skills you might need 6feet on one side to setup the triballs. 

• Buidling space to store pieces preselected to build prototypes or experiment. 

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Step 3: Where do you start as a coach or a student? As a coach reach out to your Team Engagement Manager and take your new members to an event. Reach out to other coaches in your area, and visit another organization so you and your new team members can learn best practices from peers. Review the rubrics. Connect with mentors/judges, and schedule online or in person teaching sessions so your team can start the season well informed.

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Step 4: Register your team on robotevents.com. Check out the different events for the season in your qualification area/region. Lake County, Florida is in the North/Central Florida region. Have a "parents and students" meeting to plan out the season and discuss availability, travel cost and additional registration fees. Have support members in case one team member can not attend an event. Support members can be team members from another robotics team that can help at a competition without becoming a permanent member of the team. This is beneficial for smaller teams that might need help for logistics, scouting and even driving. 

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Step 5: Volunteer at an event, reach out to the Team Engagement Manager who can guide both the coach and the students on how to get a lot of knowledge in a short period of time. Certifications for drive team, referee and judge are strongly recommended for everyone involved and the certifications are free and online.

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Step 6: Explain the importance of an engineering notebook. The team needs to start an engineering notebook (paper or digital) with an intro of the team, background. Explain why you are doing robotics, do you have any experience with other robotics or programming. Before you start building, you need to know what you are going to build, what your constraints are both in materials and time. Explain what your game strategy is going to be for head to head matches, and skills. Are you going to use sensors for the autonomous skills and the autonomous part in head to head? Document your decision process. Identify how you are going to score points and what qualities/abilities the robot needs to have to perform the tasks. 

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Step 7: Divide up the work, so everyone can be contributing to the same goal. Go over different Student roles identified in the game manual, but explain that for the first robot build iteration everyone can learn from having each of these roles. 

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• Designer – The Student(s) on the Team who design(s) the Robot. Adults are permitted to teach the Designer(s) how to use concepts or tools associated with design, but may never work on the design of the Robot without the Designer(s) present and actively participating.

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 • Builder – The Student(s) on the Team who assemble(s) the Robot. Adults are permitted to teach the Builder(s) how to use concepts or tools associated with Robot construction, but may never work on the Robot without the Builder(s) present and actively participating.

 

• Programmer – The Student(s) on the Team who write(s) the computer code that is downloaded onto the Robot. Adults are permitted to teach the Programmer(s) how to use concepts or tools associated with programming, but may never work on the code that goes on the Robot without the Programmer(s) present and actively participating.

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Based on the game strategy identified in step 6, the minimum needed to participate, is a robot with a controller to drive in the Head-to-Head matches and the driver controlled skills. It can be an option for the team to wait with the autonomous part for iteration 2. 

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A robot has different parts. 

Review the definition of a VEX robot in the inspection rules.

What is subsystem 1?

What is subsystem 2?

What is subsystem 3?

Can you have more than one of any of these systems at a competition?

What part can be programmed?

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One person can be researching the best drivetrain to move around on the field, another can be researching how to manipulate any of the game elements, someone might be looking at how the use sensors to accomplish any tasks.

 

Each of these subsystems should be documented by using the engineering design process and will have an impact on game strategy and overall goal.

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How many motors will be used? What type of motor, what type of gear cartridge? Document the entire process from identifying each subsystem, to presenting different possibilities to all your team members, selecting a solution. Make a sketch, use a picture from online robot examples or create a CAD drawing in OnShape. Don't start building without communicating or documenting. You can sign up for a free educator or student account. Watch the video. Subscribe to the free monthly VEX library and watch this to get started. 

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Check out this great instructional video from the Purdue Sigbots on drivetrains, the video will open in a separate window. 

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Step 8: Identify all the electronics you will be using to build the 3 subsystems. Make a list of anything missing. Update the firmware on all the electronics. Does the brain have any build in settings that need to be modified?

Do you have a backup battery to go to competition, backup motors with the correct gear cartridge if applicable? What tools do you need to open the motor etc.

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Coach tip: Get to know all the electronic components and review any of the sensors, some are not included in the kit and need to be ordered. Check with the Team Engagement Manager if a team near you might have an extra sensor you can borrow or buy used. Identify the minimum configuration needed to have a competitive robot this season.

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V5 brain

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The VEX v5 Brain has 21 SMART ports, 8 built in 3-wire port, a full color touchscreen and can hold up to 8 user programs. You can connect up to 2 wireless controllers to a brain (requires a radio). This brain requires an external battery and a special cable to connect the brain to the battery. 

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V5 Brain provides 21 Smart Ports Fig. 1,  which recognize and utilize the V5 Smart Motors, V5 Electromagnet, V5 3-Wire Expander, V5 Radio, and V5 Sensors, as well as allowing for a wired connection to the V5 Controller.

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  Fig. 1                                                                                                        Fig. 2

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The Brain also has eight 3-Wire ports Fig. 2, which can be configured to accept the legacy Servo, the Pneumatic Solenoid Driver, LED’s, and 3-Wire Sensors.

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Smart Motors:

The total amount of motors allowed in the competition is 88W.

• A V5 Smart Motor is 11W (large).

• A VEX EXP Motor is 5.5W (small).

 

A robot can have a combination of large and small motors. 

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The V5 Smart Motor has three options for easy-to-replace internal gear cartridges. There is a red cap cartridge with an output gear ratio of 36:1 (100 rpm) for high torque & low speed which is best used for lifting arms, moving claws, and other high torque mechanisms. There is a green cap cartridge with an output gear ratio of 18:1 (200 rpm) for standard gear ratio for drivetrain applications. There is a blue cap cartridge with an output gear ratio of 6:1 (600 rpm) for low torque & high speed which is best used for intake rollers, flywheels, or other fast moving mechanisms. The V5 Smart Motor Gear Cartridge can be switched by using the following steps.

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The VEX EXP Motor has a fixed internal gear with a speed of 200 RPM and a torque of 0.5. You can find more details here. 

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Calculate the output rpm of each of the drivetrain and each manipulative based on the gears used. Check to make sure that it balances speed and torque for each application. You can find a great article about different type of gears here. 

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​​How to start coding in the virtual playground with blocks or Python?

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Every team registered for the VRC competition receives a virtual skills key. The website to start coding in virtual reality is  vr.vex.com

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If you are brand new to coding, there are several free resources available.​

The virtual playground looks like the actual game field and is a great way to test different game strategies for autonomous skills with the hero bot for the season. This year, the hero bot is Striker. The virtual playground allows anyone to explore how different sensors can be used as the virtual hero bot is using different sensors.

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Click here to read how to start. 

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Virtual Skills Standings are posted on robotevents.com

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How to start programming the controller?

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Default ports are using default buttons on the controller. 

You can change the buttons for each motor or sensor plugged into the brain. 

You can also program a set of steps the robot will do by pressing a certain button. 

Reminder: use the competition template for Head-to-Head Matches at competition. You don't need the template for driver skills or autonomous skills. 

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How to use PID or Proportional Integral Derivative feedback control to reduce errors of motor outputs?

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https://docs.wpilib.org/en/stable/docs/software/advanced-controls/introduction/introduction-to-pid.html

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Carnegie Mellon Robotics Academy offers free courses through CS2N.org to learn to code with VEXCode C++. 

There is also a mechanical foundation course for VEX v5 explaining the importance of a good drivetrain.

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For VRC competitions in North/Central Florida click here. 

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