An Introduction to Fling: the `21-`22 VIQC Hero Bot

Scoring a Ball in the High Goal

Using Fling’s Intake and Catapult Arm, Balls can be efficiently scored in the High Goal.

Scoring a Ball in the Low Goal

Balls can be easily pushed into the Low Goal using Fling’s Intake.

Clear the Balls from the Corral

Fling can use the Intake to effectively clear the Balls from the Corral.

Low Hang from a Hanging Bar

Fling is able to use the Catapult Arm to reach up and low hang from a Hanging Bar.

Fling’s Intake consists of two 40 millimeter (mm) pulleys separated by standoffs, and four rubber bands stretched between the pulleys.

The rubber bands effectively grab onto the Balls as the Intake spins.

The Intake can spin to pull in a Ball, or be reversed to release a Ball.

The power from the Intake’s motor is transferred by using two 10 millimeter (mm) pulleys and a rubber belt.

This provides a smooth transfer of power. If a Ball should get jammed in the Intake, the rubber belt will just slip, preventing any damage.

The firing mechanism for Fling’s Catapult Arm is a very smooth reciprocating device.

It consists of a set of 60 tooth gears and an articulated tensioning arm.

The tensioning arm pivots on a pin attached to the outside edge of the gears. This creates a crank setup as the gears turn.

On the opposite side of the gear from the pivot connection is a Shaft bushing. The bushing will catch the tensioning arm and increase the crank’s length.

As the crank causes the articulated tensioning arm to become shorter, it pulls down the Catapult Arm and increases the tension on the Catapult Arm’s rubber bands.

Once the crank linkage moves past the over center point, the Shaft Bushing loses contact with the crank linkage and releases the tensioning arm, firing the Catapult.

This entire cycle repeats itself as the gears continue to turn, as shown in this animation. The Bumper Switch is set up to trigger the behavior of stopping the gears from turning, just prior to the Catapult Arm reaching its over center point.

This allows a Ball to be loaded onto the Catapult Arm from the Intake.

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

The gear system for the Catapult Arm needs to have enough rotational torque to overcome the tension of the arm’s rubber bands. In addition, the Catapult Arm is used to hang from the Hanging Bar, so it also needs to have enough torque to lift the robot’s weight.

This torque is generated by using a two stage compound gear ratio.

The first part of the compound gear ratio has the 12 tooth driving gear, which is powered by the motor.

The 12 tooth driving gear drives a 36 tooth driven gear.

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

The 36 tooth gear rotates at 1/3 the speed of the motor. However, it transfers 3x the rotational torque to its shaft.

The second part of the compound gear ratio has a pair of 12 tooth driving gears. These 12 tooth gears share the same shaft as the 36 tooth gear from the first part of the compound gear ratio.

There are a pair of 36 tooth idler gears between the pair of 12 tooth gears and the pair of 60 tooth gears on the Catapult firing mechanism. Idler gears do not change the gear ratio.

These 12 tooth gears into 60 tooth gears provide a 5:1 gear ratio.

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

At nearly 15x the Catapult motor’s rotational torque, this provides Fling with plenty of rotational torque to both fire the Catapult Arm and lift its weight off the Field using the Hanging Bar.

• For more information on gear ratios, Sprockets, and Pulleys, view this article from the VEX Library.

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

To configure Fling’s specific 2-motor drivetrain, select port 1 for the left motor and port 3 for the right motor.

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

• change the track width from 173 mm to 267 mm.

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

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

• To configure Fling’s specific Intake Motor, select port 2.
• To configure Fling’s specific Catapult Arm Motor, select port 4.

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

To configure Fling’s specific Bumper Switch, select port 5.

The IQ Controller can be configured to drive Fling as well as control the Intake.

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

Note: Fling’s configuration does NOT allow the VEX IQ Brain’s default driver's program to work with the controller.

Any of the button groups on the controller can be used to control Fling’s Intake.

Note: Fling’s Intake must be configured first before configuring the controller.

Set the CatapultArmMotor stopping to hold. This will keep Fling’s Catapult Arm held in place after hanging.

Choose a controller button to set up Fling’s Catapult Arm to fire.

Choose a controller button to fire the Catapult Arm.

This button will also move the arm down to allow Fling to hang on the Hanging Bar.

For more information on how to code Fling using VEXcode IQ, view these articles from the VEX Library.

Fling has been designed to easily add any of the IQ Sensors. The Pitching In game robot rules allow for plenty of customization to your Fling Hero Bot.

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

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