Robotics I Gears and Motors

Servo Motors

100

A twisting force that tends to cause rotation.

What is Torque?

200

Twisted or coiled wires that current flows through to create a rotating magnetic field.

What is Winding?

300

The part that transmits the motor output power to the machine.

What is the shaft?

400

A high-function rare earth or other permanent magnet that is positioned externally to the shaft.

What is the rotor?

500

The optical piece that watches the number of rotations and the position of the shaft.

What is an Encoder?

Gears

100

Work with motors to control a robot’s speed and torque. They are wheels with teeth that mesh together to transfer motion and force.

What is a Gear?

200

The relationship between the size of two gears working together. Calculated by comparing the number of teeth on the output gear to the input gear.

What is a Gear Ratio?

300

• The output gear is larger and turns more slowly than the input gear.
• Effect: Increases torque (strength) but reduces speed.
• Example: Useful for lifting heavy objects with a robot
• 4:1

What is a High Gear ratio?

400

• The output gear is smaller and turns faster than the input gear.
• Effect: Increases speed but reduces torque.
• Example: Useful for a fast-moving robot.
• 1:4

What is a Low Gear Ratio?

500

A system of multiple gears working together. By combining gears, you can fine-tune the speed and torque of a robot to match the task it needs to perform.

What is a Gear Train?

Newton's Laws

100

An object’s resistance to changing its motion. If something is not moving, it won’t move unless something pushes it. If it’s already moving, it will keep going in the same direction and at the same speed unless something stops or changes it.

What is Inertia?

200

Law of Inertia: "An object at rest stays at rest, and an object in motion stays in motion, unless acted upon by an external force.” 

What is Newton's First Law?

300

Action-Reaction: “For every action, there is an equal and opposite reaction.”

What is Newton's Third law?

400

Force = Mass X Acceleration: “The force needed to move an object is equal to its mass multiplied by its acceleration.”

What is Newton's Second Law?

500

The better the robot’s wheels or tracks grip the surface, the more force it can apply without slipping. This is important on smooth surfaces like tile or slippery surfaces like ice.

What is Traction?

Gears 2

100

Gear A has 20 teeth and spins at 100 RPM. Gear B, which is meshed with Gear A, has 40 teeth. What is the RPM of Gear B?

50 RPM

200

A motor spins Gear X at 300 RPM. Gear X has 12 teeth and is meshed with Gear Y, which spins at 100 RPM. How many teeth does gear Y have?

36 teeth

300

A gear system where a central "sun" gear is surrounded by multiple smaller "planet" gears that rotate around it on a carrier, all meshing with an outer "ring" gear.

What is a Planetary Gear Train?

400

• A screw-shaped gear that meshes with a regular gear.
• Great for high torque and holding a position without slipping.

What is a Worm Gear?

500

Gear 1 has 10 teeth and spins at 200 RPM. Gear 2 has 50 teeth and is meshed with Gear 1. Gear 2 is connected to Gear 3, which has 20 teeth. What is the RPM of Gear 3?

100 RPM

DC and Servo Motors

100

_____ is what keeps the wheels from slipping. Too little _____ (like on ice) means the robot’s wheels spin without moving it forward. Too much _____ (like sticky mud) can slow the robot down.

What is friction?

200

These motors spin continuously when powered and are great for making a robot move forward, backward, or spin in circles.

What is a DC Motor?

300

This motor is used for precise movements. Instead of spinning all the way around, they can be programmed to turn to specific angles.

What is a Servo Motor?

400

• Angle Control: This motor can turn to, say, 90°, 180°, or any other angle you specify.
• Torque: They can also produce high torque, which makes them strong enough to lift or hold objects at a specific position.
• Built-in Control: These motors have a feedback system that tells the motor its position, which allows for accurate control.

What is a servo motor?

500

• Continuous Rotation: They don’t stop unless you turn off the power or control them with a signal.
• Speed Control: You can make them spin faster or slower by changing the amount of power sent to them.
• Torque Control: Torque is the "strength" of the motor. To increase torque, you can use a higher gear ratio.

What is a DC Motor?