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Robotic Actuators

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Robotic Output Devices / Actuators

Movement

Actuators produce movement. The movement can result in the robot itself moving. Also the movement can turn on electrical, hydraulic or pneumatic compressed air devices used to control machinery such as fluid flow control valves. There are some interesting videos covering this area on the video links page. Interesting new materials are being developed that might be useful as robotic actuators.

Small linear movements - Solenoid

The solenoid uses an electromagnet which is either on or off.
The solenoid produces a small movement of a magnetic iron core when the electromagnet is on.
They are available in tiny milliwatt versions up to big items rated up to 100 watts.

Rotation

Stepper Motor
The motor runs in precise steps.
Use a microcontroller to control the position with precision.
The position need not be measured.
The head in an ink jet printer is moved with a stepper motor.
Conventional Motor
Used when higher powers are needed.
Position can be measured with a linear Gray code scale.
Speed can be measured with a slotted comb-like grid, counting flashes of infrared passing through the slots

Small angular movements

Servo
This is controlled with a stream of accurately timed pulses.

Sound

Warning sounds
Speech - For example horrible telephone answering robots
- "If you want to borrow money, press 1."
- "If you want to pay a bill, press 2."
- "To talk to a person, please hang up."

Light

Indicator lights - LEDs
Small amounts of numeric output - Seven Segment Displays
Small mounts of text output - LED Matrix Displays
Short or longer text messages - LCD Screens
Graphical displays - LCD Screens