Wiki

[technik3k]

Reserved for all Omni tank drive

[technik3k]

Reserved for X-Drive wiki entry

Why is X-Drive Faster? - AURA

2 vs 4 motor drive

Here, this is the most important graph to understand X-Drive:

Source: AURA

If you drive forward, backward, or to the side - all four motors are providing power, the velocity is MotorRPM x sqrt(2) and pushing force is 4 x OneMotorTorque/sqrt(2).

If you drive at a diagonal, then only two motors are providing power, velocity is MotorRPM and pushing force is 2 x OneMotorTorque.

Essentially, X-Drive speed is 1.41 times faster and pushing force is 1.41 times weaker than the ordinary tank drive with the identical 4 wheels & 4 motors.

Also, here are the links to the similar topics from the previous seasons: Two motor drives? , X-Drive Speed , Extinct X-Drive?

[technik3k]

Reserved for H-Drive wiki entry

https://en.m.wikipedia.org/wiki/H-drive

H-Drive?

[technik3k]

Reserved for Mecanum wheels drivetrain wiki entry

Omni wheel vs Mecanum

Meccanum Problems

You need to make sure that your mecanum wheels are mounted correctly. They need to have a specific orientation. The bottom of the robot they should look like this…

Code examples:

Vexcode Mecanum Wheel Program

Tank control

int left = Controller.Axis3.position(vex::percent);
int right = Controller.Axis2.position(vex::percent);
int sideways = Controller.Axis4.position(vex::percent);

//you can also calculate this...
int turn =    (right - left) * 0.5;
int forward = (right + left) * 0.5;

frontRight.spin(vex::forward, right - sideways, vex::percent);
frontLeft.spin(vex::forward,  left  + sideways, vex::percent);
backRight.spin(vex::forward,  right + sideways, vex::percent);
backLeft.spin(vex::forward,   left  - sideways, vex::percent);

Arcade Drive

int forward = Controller.Axis3.position(vex::percent);
int sideways = Controller.Axis4.position(vex::percent);
int turn = Controller.Axis1.position(vex::percent);

frontRight.spin(vex::forward, forward - sideways + turn, vex::percent);
frontLeft.spin(vex::forward,  forward + sideways - turn, vex::percent);
backRight.spin(vex::forward,  forward + sideways + turn, vex::percent);
backLeft.spin(vex::forward,   forward - sideways - turn, vex::percent);

A Holonomic drive is free to move in any direction without having to rotate around its axis.

https://en.wikipedia.org/wiki/Holonomic_(robotics)

One form consists of 3 or 4 omniwheels mounted at angles to each other. It is good for lateral movement, and increases speed and power of turns. However, linear drive speed and power are decreased since some or all of the powered wheels run at angles to the bot’s motion. All wheels must be omni wheels in order for this drive to function. The 4-wheel version is referred to as " X-Drive".

Another omniwheel Holonomic drive is the “H-Drive”, where 1 omniwheel is placed at right angles to the other four conventionally mounted omniwheels.

Mecanum drive is holonomic drive where four mechanum wheels are placed in a tank drive format. The wheels should look like this when looking from top:

Like all holonomic drives, mechanum bots can strafe, and does so with a simple rectangular base. However, mechanum wheels have rollers that slip, reducing traction and pushing power.

[technik3k]

Reserved for additional drivetrain discussion entry

Kiwi:

@rhowbot

Kiwi Drive Bot

Lynfield:

@vdsa

Swerve:

@93870A

Shifting X-Drive

…

[technik3k]

Reserved for additional drivetrain discussion entry

Are tracked vehicles viable in Vex?

[technik3k]

Reserved for additional drivetrain discussion entry 1

[technik3k]

Reserved for additional drivetrain discussion entry 2

[technik3k]

Reserved for additional drivetrain discussion entry 3

[technik3k]

Reserved for comparison of the VEX wheel types

Omni wheel vs Mecanum

The first table shows coefficient of friction calculated by dividing the force by the base weight, which experimentally accounts for both material-to-material and rolling friction:

And the second table shows the amount of force (in lbf) required to pull or push a typical 15 lb robot:

Conversion of the robot weight into tractive force:

https://sites.google.com/site/dkellytest1/drive-systems/comparison-of-wheels

[technik3k]

Reserved for discussion of the Claw (intake)

[technik3k]

Reserved for Side Rollers wiki entry

Are side rollers usefull???

[technik3k]

Reserved for Passive Intakes wiki entry

Need help with reverse double four bar!

Here is an album of pics of our worlds ITZ robot

[technik3k]

Reserved for Top Roller intake wiki entry

1200B Mainframe Meltdown Worlds Reveal

[technik3k]

Reserved for the (ball) indexer discussion

315G Ratchets Explained (6 motor drive, 2 motors for everything else)

315G’s Turning Point Ratchets Explained

Mini Reveal- Single Motor Feeder and Indexer

Indexer vs Extra Flywheel Motor

https://youtu.be/MqD8EmWweB8

[technik3k]

Reserved for Flywheel discussion wiki entry

Flywheel • Renegade Robotics

Single flywheel:

Remembering the best

Dual flywheel:

Dual Flywheel Help

7842F 2018-19 Robot Showcase - Flywheel Control, Odometry, Engineering Journals & More

PID Theory Question

Additional links: Physics of the Flywheel Launcher

Advanced topic: adjustable hood…

[technik3k]

Reserved for (ball) Puncher wiki entry

Puncher Help

See also: slip gears
Advanced topic: adjustable angle punchers

[technik3k]

Reserved for Catapult launcher wiki entry

Best Ball Launcher for Accuracy?

If done properly, catapult can be even more efficient than flywheel.

8059A and D : SingVex (Reveal)
8059D Catapult Hybrid: Singapore VEX 2016 Edition (Reveal)
2-Ball Catapult vs 1-Ball Flywheel

[technik3k]

Reserved for additional exotic game object launcher mechanism 1

[technik3k]

Reserved for additional exotic game object launcher mechanism 2