An Introduction to Moby: the V5RC Tipping Point Hero Bot – VEX Library

Each year, the V5 Hero Bot is designed from the VEX V5 Competition Starter Kit to provide teams with a starting point to play the current VEX Robotics Competition game. It is intended for experienced teams to be able to quickly assemble a robot to investigate the game's dynamics. New teams can also use the Hero Bot to learn valuable building skills and have a robot they can customize to compete with early in the season.

The 2021-2022 VRC Game is Tipping Point. View this page for more information on the game and how it is played. This season's Hero Bot to play Tipping Point is Moby. You can view Moby’s build instructions for more information.

For game definitions used throughout this article, an overview of the game rules, and scoring, view the Game Manual for Tipping Point.

Scoring Capabilities

Moby can score in the following ways:

Moby Hero Bot is shown scoring a Preload Ring on a Mobile Goal on the game field.

Scoring Preload Rings into a Mobile Goal.

Each side of Moby’s Forks can hold up to two Rings, which leaves plenty of capacity to handle all three of the Preload Rings.

Moby Hero Bot is shown on the game field driving to pick up Rings with its Forks.

Pick up Rings from the Field to score in Mobile Goals.

Rings can be picked up off the Field’s floor using Moby’s Forks.

Moby Hero Bot is shown picking up a Mobile Goal with its Forks.

Lift Mobile Goals and move them into the Alliance Home Zone.

The Forks can be lowered to slide under the edges of a Mobile Goal. The Forks can then lift and pick up the Mobile Goal to be carried into the Alliance Home Zone.

Two Mobile Goals are shown placed on the red Alliance Platform on the game field.

Place Mobile Goals to be elevated on the Alliance Platform.

After a Mobile Goal has been picked up it can be placed on your Alliance Platform. Note that Moby can only place a Mobile Goal on the Platform with the Mobile Goal in it's possession, this is because Moby's design cannot reach high enough to place Mobile Goals on the Platform when the Platform is already balanced.

Two robots on the blue team are shown on top of the blue Alliance Platform.

Elevate your robot on the Alliance Platform by driving on the platform until it is balanced.

Moby’s Forks can be used to lower the Alliance Platform when it is balanced. This will allow Moby to drive up on the platform.

Design Features

Two of Moby's prominent design features are its 2-motor direct drive drivetrain and its compound gear ratio 2-motor lift for the Forks.

2-Motor Direct Drive Drivetrain

Angled view of the Moby build to highlight the 2 motors that power its Omni-Directional driving wheels directly.

Moby has a 2-motor direct drive drivetrain. This makes for an easy to assemble and effective drive for the robot.

Direct drive refers to having the shaft go directly from the motor to the wheels without using gears or a chain and sprocket system.

The two motors power the rear wheels making this a rear-wheel drive robot.

For more information on drivetrains, view this article from the VEX Library.

View of the Moby build on the game field with its two Omni-Directional drive wheels highlighted.

The drive wheels are Omni Directional Wheels.

Omni Directional Wheels have rollers around the circumference of the wheel which allows the wheel to roll in two directions - frontwards/backwards and sideways.

The Omni Directional Wheels will allow for easy turning of the robot. Moby turns about the center of the Forks to make lining up to Mobile Goals easier, as shown in this animation.

Compound Gear Ratio 2-Motor Lift for Forks

Angled view of the Moby build with its two Compound Gear Ratio mechanisms highlighted.

Anyone who has ever tried to pick up a broom by holding onto the very end of its handle has experienced rotational torque.

With the mobile goals weighing in between 1520 grams and 1810 grams, depending on the goal, it takes a large amount of rotational torque to lift the Mobile Goals with the Forks.

This torque is generated by using a compound gear ratio.

Close up of the Compound Gear Ratio on the Moby build. The first gear ratio is highlighted, and it shows a motor powering a 12 tooth gear which is driving a 36 tooth gear.

The first shaft has the 12 tooth driving gear which is powered by the motor.

The second shaft has a 36 tooth driven gear.

This 12 tooth gear into a 36 tooth gear provides a 3:1 gear ratio.

The second shaft rotates at 1/3 the speed of the motor, however, it has 3 times the rotational torque.

Close up of the Compound Gear Ratio on the Moby build. The second gear ratio is highlighted, and it shows the previous 36 tooth gear connected to a 12 tooth gear which is driving a 60 tooth gear.

The second shaft also has a 12 tooth gear on it which becomes the driving gear.

The third shaft (screw) has a 60 tooth driven gear attached directly to the Fork.

This 12 tooth gear into 60 tooth gear provides a 5:1 gear ratio.

Combining the two gear ratios of 3:1 and 5:1 form a compound gear ratio of 15:1

Moby has two motors in a motor group and both of them have the 15:1 compound gear ratio between the motors and the Forks. At nearly 15 times the two motors’ rotational torque, this provides plenty of rotational torque to pick up any of the Mobile Goals on the Field.

For more information on gear ratios, view this article from the VEX Library.
For more information on how to code Moby's Forks using a compound gear ratio, view this extension activity from VRC Virtual Skills's Lesson 2.

Tips and Tricks for Programming Moby with VEXcode V5

Configuring Moby's Drivetrain

VEXcode V5 Devices Drivetrain configuration menu with the Smart Port options highlighted so they can be changed to match the Moby robot's drivetrain motors. The left motor should be on Port 1 and the right motor should be on Port 10.

Follow the steps in this article from the VEX Library for general information on how to configure a 2-motor drivetrain.

To configure Moby's specific 2-motor drivetrain, select port 1 for the left motor and port 10 for the right motor.

VEXcode V5 Devices Drivetrain configuration menu with the Track Width option highlighted and changed to 375mm to match the Fling robot's track width.

To ensure the settings are adjusted for Moby’s physical dimensions:

change the track width from 295 mm to 375 mm.
change the wheelbase from 40 mm to 0 mm.

Note: a 2-wheel drive drivetrain only has one drive shaft on each side of the robot, so it will have a 0 millimeter wheelbase.

For more information on track width and wheelbase, view this article from the VEX Library.

Configuring the Fork's Motor Group

Diagram of the Moby build from the side with lines marking the arc of its forks.

To control both motors together, the Fork’s motors need to be placed in a Motor Group.

For more information on building with Motor Groups, view this article from the VEX Library.

VEXcode V5 Devices menu after the Add a device button has been selected. The Motor Group option is highlighted.

Follow the steps in this article from the VEX Library for general information on how to configure a Motor Group.

To configure the motor group for Moby's Forks, select port 2 for Motor A and port 9 for Motor B.

VEXcode V5 Devices window with the Motor Group Settings menu shown. Below, the Reverse Motor option is selected and highlighted. These buttons can be used to reverse one Motor in the Motor Group, or both. In this example, only the Port 9 motor is reversed.

To ensure Moby's Fork motors drive in the correct direction together in the motor group, toggle the port 9 motor to reverse.

Configuring Moby's Controller

VEXcode V5 Devices menu after the Add a device button has been selected. The Controller option is highlighted.

The V5 Controller can be configured to drive Moby as well as control the Forks.

Follow the steps in this article from the VEX Library for general information on how to configure a controller.

VEXcode V5 Device Menu with the Controller options opened where the controls can be changed. The joysticks are set to a Tank Drive configuration, and the R shoulder buttons are set to control the Fork Motor Group.

Any of the button groups on the controller can be used to control Moby’s Forks.

Note: Moby’s Forks must be configured first before configuring the controller.

V5 Competition Template

Thumbnail image for the VEXcode V5 Competition Template project.

Remember if you are planning on taking Moby to a competition, they will be using a field control system.

You will need to create your project using the Competition Template example project.

For more information on using example projects, view these articles from the VEX Library:

Adding V5 Sensors

Angled view of the Moby build to highlight its Sensors and show that it has space for more to be added.

Moby’s chassis has been designed to easily add any of the V5 Sensors. The Tipping Point game robot rules allow up to 8 motors as well as pneumatics. This allows for plenty of customization to your Moby Hero Bot.

For more information on V5 Sensors, view this section of the VEX Library.

You can also view this article on Virtual Moby used in VRC Virtual Skills to see examples of how sensors can be added to Moby.