Sensors and Actuators

Sensors are devices which measure quantities which the robot can use to achieve given tasks.

Examples of what a robot may need to determine include:

• How far away and where is an object (like another robot, a light, a wall)?
• At what speed is the robot moving?
• If the robot is on a hill, at what angle is it?
• If the robot is rotating, by how much has it rotated?
• Where is the robot, or in what direction is it going?
• How far it has it travelled (which is odometry)?
• How much power has it consumed?
• What information is being communicated to the robot?

The robot may require internal and external sensors.

External sensors are used to measure other objects, for instance:

• How far away is an object?
• Where is the object?

Internal sensors are used to measure the robot itself, for instance:

• How fast it is going
• The angle of the robot
• Where it’s ‘gripper’ is
• How much power it’s consuming

Actuators

An actuator is a device which causes something to happen.

This could be a robot movement, which is often achieved using motors:

• An actuator is needed to make the robots wheels turn.
• Or the joints of a robot arm to rotate.
• Or for a robot gripper to open or close.

Or it could be to let the others know what the robot is doing.

• A light being turned on to indicate the robot is working.
• Sound is being emitted – so the actuator is a loudspeaker.
• Communication in some form – so a transmitter is needed.
• An LCD (Liquid Crystal Display) screen for showing pictures and other data.