How a Pneumatic Robot Arm Works

Posted on: February 12, 2020

We might not think about them much, but robotic arms build many of the items that we used every day. Have you ever wondered how they work? Let’s take a closer look at the inner workings of a pneumatic robotic arm.

Pneumatic Arm Basics

A pneumatic arm, like any other air-powered system, needs five things to work. It starts with the compressor, which generates the compressed air. This then moves to a reservoir, which stores the air. Valves then control the air flow, and circuits control the valves moving the air between the parts that need it. Finally, an actuator uses the air to do something.

A basic robotic arm is made up of a base and several actuators. This number varies based on the robotic arm design.

The base, or shoulder, is the part of the arm that rests on the floor or an elevated surface and provides a stable foundation for the rest of the arm. From there, the actuators – the upper arm, the elbow, forearm, the wrist, and the hand – give the robot its movement. Each section can be controlled individually, enabling more accurate control.

How Does a Pneumatic System Power a Robotic Arm?

There are four steps in any pneumatic system when it comes to powering robotic arms. First, the compressor uses gasoline, propane, or electricity to generate compressed air. Any of these can serve as the power source for the pneumatic system, storing potential energy.  From the compressor, this air moves into the reservoir. It is stored here until it is needed by the robotic arm so that the system can be used immediately instead of waiting for the compressor to generate enough pressure.

The valves in each component determine how each will move. Turning the air on and off determines the motion of each piece of the arm.

Finally, the actuators turn the potential energy generated by the compressor back into kinetic energy. The actuators can be programmed to use that kinetic energy to manipulate the pneumatic arm. The use of compressed air is designed to replace electric motors and servos in the arms, making it easier to move a load or manipulate a part that is being assembled.

infographic depicting how a pneumatic robot arm works

Advantages of Pneumatic Systems in Robotics

Why are pneumatic systems starting to replace servos and electric motors in robotics steadily?

System maintenance is much simpler with pneumatic arms. If a pneumatic piston fails, it is easy to replace and takes less time than repairing an electronic system.

Pneumatics are also extremely precise. They can be programmed up to 2mm precision and have a repeatability of 0.02mm.

They also work well in extreme temperatures, both hot and cold. The standard operating range of a pneumatic arm is between -40 C and 120C (-40F to 248F).

Pros and Cons of a Pneumatic Robotic Arm

These arms can be used nearly any industry, but they are not infallible. Here are some pros and cons of using these air-powered robotic arms.


  • Pneumatic power generates much more fluid movement, reducing error and damage.
  • Low Safety Risk – These arms are safer to work around. If there is an issue, you can cut off the air to the arm without having to cut off the supply to the whole plant.
  • Less Maintenance – Pneumatic arms require less overall maintenance and are easier and cheaper to repair if they do fail.



  • Minimal Speed Control – Most pneumatic arms have two settings – on and off. It is more difficult to control the speed at which these arms move.
  • High Long-Term Operating Costs – While they can be more efficient, these arms do cost more in the long term to operate.
  • Prone to Moisture – Just like any compressed air system, these pneumatic arms can be prone to moisture damage and moisture buildup inside the compressor.


Industry Applications of a Pneumatic Robotic Arm

Robotic arms are useful for tasks that are repetitive or might be too dangerous for human employees. This includes things like welding, computer manufacturing, material handling, material removal, and manufacturing assembly lines.

Just because they’re popular in the manufacturing industry doesn’t mean that robotic arms don’t have applications elsewhere. They can be used as surgical assistants or for the creation of prosthetics and orthotics in medicine.

They can also be used in entertainment, in the form of animatronics, or for educational toys. There are even some experiments going on that are utilizing pneumatic robotic arms for automatic crop harvesting.

The next time you get in your car, or head to the doctor for a surgical procedure, thank an engineer and the pneumatic robotic arms that they programmed to make your life a little bit easier or a little bit safer.