Question: what are eight key components to every robot?
Answer: Actuation: ADVERTISEMENTS: ... 
Motors: The vast majority of robots use electric motors, including bushed and brushies DC motors.
Stepper motors: ADVERTISEMENTS: ... 
Piezo Motors: A recent alternative to DC Motors are piezo motors or ultrasonic motors. ... 
Air Muscles: ... 
Electroactive polymers: ... 
Elastic Nanotubes: ... 
Manipulation: