Intro to Robotics

EPGY Middle School ProgrammingAdam Leeper

What is a robot?

What is a robot?

What is a robot?

What is a robot?

What is a robot?

• Can sense the environment.• Can make independent decisions.• Can complete a task automatically.

Robot vs. Humans

• Pros:– Robots can be arbitrarily fast, strong, or large. – Robots can record vast amounts of data.– Robots can run in dangerous environments.

• Cons:– Robots are stupid and inflexible.– Robots are really bad at dexterous manipulation.– Robots are dangerous.

What senses do robots have?

• “Vision”– Cameras– IR range sensors

• “Hearing”– Microphones

• “Touch”– Bump sensors– Capacitive and resistive sensors

What senses do robots have?

• “Other”– Ultrasonic– Radio/GPS

• Smell/Taste– Maybe smoke detectors, but not commonly used.

Ultrasonic Sensor

• Uses high-frequency sound we can’t hear.• Sound travels at 343 m/s in air.• Can measure distance by measuring time

between a ping sent and received.

Touch Sensor

• Simplest is a contact switch.• An electrical path is completed when pressed.

Resistor

Power

Ground

Switch

Sensor output

Light Sensor

• Many types.• Similar to a touch sensor, a simple light sensor

has an electrical semiconductor component that changes resistance when exposed to light.

Sound Sensor

• It’s a microphone!• Sound waves are converted to electrical

signals.

How do robots make decisions?

• Individual sensors.• Sensor fusion.• Statistical methods.• Math formulas from a variety of science areas.

– http://www.youtube.com/user/WillowGaragevideo#p/u/30/VWxAk7Yeifs

Open-loop vs. Closed-loop

• This is the field of Controls.• Open-loop– Simple, but can have large errors.

• Closed-loop– Requires sensors, but can correct for errors.

Temperature Controller

Desired temperature

Controller Actuator(Heater)

Sensor (thermometer)

Actual temperature

Cool Robot Videos

• http://www.youtube.com/user/WillowGaragevideo#p/u/2/HMx1xW2E4Gg

• http://www.youtube.com/user/WillowGaragevideo#p/u/31/0WtGgpuS3qE

How do robots move?

• Motors and wheels• Legs

http://www.youtube.com/watch?v=W1czBcnX1Ww

Drive Train

• Direct Drive– Efficient, no backlash– Low torque

• Gear Transmission– High torque– Friction, noise, and backlash

• Belt/Cable Drive– Placement, performance– Complex

The NXT motor

Choosing wheels

• Large wheels– High top speed, good clearance, – Low torque (acceleration)

• Small wheels– High torque, perhaps better stability– Lower top speed