What is a robot actuator?

An actuator is any component that converts energy into physical motion. In robotics it's the part that actually moves things — turning a joint, driving a wheel, or closing a gripper. If sensors are a robot's senses, actuators are its muscles.

What is the difference between a motor and an actuator?

A motor is one kind of actuator — specifically an electric one that produces rotation. 'Actuator' is the broader word: it also covers hydraulic and pneumatic pistons, linear actuators, and shape-memory materials. Every motor is an actuator, but not every actuator is a motor.

What are the main types of actuators in robotics?

Four families: electric (motors, servos, steppers — the default), hydraulic (oil-driven pistons for huge force), pneumatic (air-driven, common in grippers), and shape-memory (alloys or polymers that contract when heated, used in soft robots).

What is a linear actuator?

A linear actuator produces straight-line push-pull motion instead of rotation. It's often an electric motor turning a lead screw, or a hydraulic/pneumatic piston. Used for lifting, extending, and pressing — anywhere a robot needs to move in a straight line.

Robot Actuators

A robot actuator is any component that turns energy into motion — the "muscles" that let a robot act on the world. The four main types are electric (motors and servos), hydraulic (oil-driven pistons), pneumatic (compressed air), and shape-memory materials. Electric actuators are the default for almost every beginner robot.

Actuators are one of the four core parts of a robot. People often say "motor", but a motor is just the most common kind of actuator. Let's explore the whole family.

Motor vs actuator — what's the difference?

An actuator is the general term for anything that produces motion from energy. A motor is one type — an electric actuator that produces rotation. So all motors are actuators, but actuators also include pistons and artificial muscles that no one would call a motor.

The main types of robot actuators

Pick a type below to see how it creates motion and where it's used in real robots.

Electric actuators

Motion: Rotary (and linear via screws)

Motors, servos, and steppers. The default for most robots — clean, efficient, easy to control. Drives wheels, joints, and grippers.

Hydraulic actuators

Motion: Linear (pistons) & rotary

Pressurised oil pushes pistons for enormous force. Used in excavators and the early Boston Dynamics Atlas. Powerful but heavy, leaky, and noisy.

Pneumatic actuators

Motion: Linear & gripping

Compressed air drives pistons. Lighter and cleaner than hydraulics but harder to control precisely (air compresses). Common in industrial grippers.

Shape-memory actuators

Motion: Contraction (muscle-like)

Special alloys or polymers that contract when heated. Silent and muscle-like, used in soft and micro robots. Slow and low-force, but no gears or motors.

An actuator is anything that turns energy into motion. Click a type to see how it moves and where you'll find it. Most beginner robots use electric actuators.

Electric actuators (the default)

The vast majority of robots run on electric actuators because they're clean, efficient, and easy to control. These split into three you'll meet constantly:

Servo motors — precise angles with built-in feedback.
Stepper motors — exact open-loop steps.
DC & brushless motors — continuous rotation for wheels and propellers.

Hydraulic & pneumatic actuators

When electric motors can't make enough force, pressurised fluid steps in. Hydraulics use oil to generate enormous force (excavators, the early Boston Dynamics Atlas) but are heavy and leak. Pneumatics use air — lighter and cleaner, but springy and harder to control precisely, which is why they shine in simple industrial grippers.