2013 FRC Drivetrain Options Advantages and Disadvantages of

2013 FRC Drivetrain Options Advantages and Disadvantages of Types of Drivetrains Team 4645

Center of Gravity The weight distribution needs to be even throughout the base of the robot. Mostly over the center of the frame rails to ensure stability.

Traction gives the ability to grip the ground. Wheels that are directly attached to motors need have a higher traction than the wheels that will be providing auxiliary actions such spacing or used just to get over obstacles.

Types of Wheels Solid Wheels • • Pneumatic Omni-wheels Mecanum Wheels Standard Wheel

Pneumatic Wheels Description- similar to tires you might find on a car these tires are filled with air. Advantages: Easy change of treads Good traction Disadvantages: Constantly monitor pressure Possibility of wheels becoming flat during competition • •

Practical uses: • Can be used in tank drivetrains and just a simple four wheel driven system.

Omni-wheel Description- the omni wheel has forward as well as sideways movement. Advantages: Greatly increases range of motion Rate of turning is much quicker Disadvantages: Less traction Less torque • •

Practical uses: The omni wheel can be used practically in a pivot design with two driven wheels • • Or, it could be used in the holonomic drive giving the robot strafing abilities

Mecanum Wheels Description: a wheel that can be used to move in any direction Advantages: Minimal Friction Ability to pivot on own axis Greatly increase steering speed Ease of getting over obstacles • •

Disadvantages: • • • Minimal Torque Speed Reduction Loss of Traction Practical uses: • Only real practical use for the mecanum wheel is in an all mecanum drive which is four driven mecanum wheels.

Standard Wheels Description- Just your basic wheel designs which may vary slightly. Advantages: Cost effective Easy to program Easy to drive Potential for high speed and higher torque • •

Disadvantages • • Less precision in steering Less agile

Types of Drivetrains • • • Tank Mecanum Swerve/Crab Slide Holonomic

Tank Drivetrains There are many different designs in the tank drivetrain class: Tread Tank Four Omni-wheel Tank Six Wheel Tank • • •

Tank Drive Train Advantage • • • Fast Speeds Very Stable Scalable (ability for more Motors and more Torque) • • Small turning radius, almost zero Ability to climb steep grades

Tread Tank The tread tank is a multiple wheel driven system that utilizes treads to gain extra traction and works closest to an actual tank, for which this category was named. The downside to the tread tank is that it loses agility and speed in the process.

Six Wheel Tank The six wheel tank is the most basic form of the tank system because its easy to assemble and is generally made up of the basic kit parts. This setup is normally the fastest in terms of forward speed. It also has a small turning radius, and is also probably the easiest to drive.

Simple Tank

Holonomic drive is a system utilizing omniwheels to gain the ability to move side to side as well as increase turning agility it can be a very useful system depending on the game but you sacrifice speed, torque, and a lot of traction. It also takes up space because the wheels are placed at a fortyfive degree angle. The holonomic drive is the predecessor to the mecanum drive system.

These arrows show the wheels are driven to allow forward movement.

Shows the direction motors are driven in order to turn. this would turn counter-clockwise but reversing the motors would turn it clockwise.

this picture shows the direction motors are driven in order to move side to side.

Holonomic Drive

Mecanum Drivetrains Utilizes four Mecanum wheels on independent motors. By using forward and reverse you are able to move in four directions without the need to turn.

Mecanum Drivetrains cont. Very similar to the Holonomic drive train, but instead of putting the wheels on a 45 degree angle the omni-directional part of the wheel is on an angle.

Mecanum Drivetrains cont.

Mecanum Drive

Mecanum Drivetrain advantages • • • Maneuverability Ability to travel over bumps Frees up space on front of robot for arms, grabbers, kickers, etc.

Mecanum Drivetrain disadvantages • • • Low traction Lower speed Can not support as much weight

Swerve/Crab Drivetrains Utilizes four wheels on an a axis that allows each wheel to rotate 360 degrees independently. Allowing a large range of motion and great maneuverability.

Swerve/Crab Drive cont.

Swerve/Crab Drive Advantages • • • Maneuverability High Traction Large weight capacity

Swerve/Crab Drive Disadvantages • • • Complex Many motors used (2 per wheel) Stability may be compromised

Swerve Drive

Slide Drivetrains Using omni wheels in a perpendicular pattern, certain motors are used to move in either of two directions. The robot then uses a combination of wheels to turn.

Slide Drive Advantages • • • Maneuverability Fairly cost effective Similar to tank drive Easy to design, train, and program Agile

Slide Drive Disadvantages • • Requires all omni-wheels Lack in torque No potential for a high pushing force Extra parts such as wheels, motors, and gearboxes required in order for sideways motion

Slide Drive

Lane Tech Team #4645 Ex Machina Any Questions?

Special Thanks / Video Credits FTC Teams 72 FRC Teams 234 1418 3105 • • and The Robologist