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Pneumatic Robot Arms: Understanding the Basics

As technology evolves, we’re able to create more and more complex systems and parts. One of the most revolutionary systems in recent decades is the pneumatic robot arm. While robot parts of old required heavy machinery, pneumatic arms are lighter and more maneuverable.

For workshops and production lines, pneumatic robot arms are indispensable. So, let’s look at how these machines work, why they’re so valuable, and how they’re used.

A pneumatic robot arm consists of five systems and six parts. The systems are the air compressor, the reservoir, valves, a circuit, and an actuator. Actuators control the physical movement of the arm. The arm parts include the shoulder (base), upper arm, elbow, forearm, wrist, and hand. These components are similar to a human arm and can replicate the same movements. 

What is a Pneumatic Robot Arm?

Pneumatics is a type of engineering that uses compressed gas or air to control mechanical movements. So, instead of using gears or fluids (aka hydraulics), pneumatic machines use tubes and air to perform tasks.

So, a pneumatic robot arm is a device that uses pneumatics to replicate the movements and capabilities of a human arm. Typically, pneumatic robot arms are used in factory and industrial settings since they can perform repeated tasks thousands of times before breaking down. Sometimes, one arm can perform multiple tasks.

How Does a Pneumatic Robot Arm Work?

There are five internal systems and six unique parts that allow the arm to move. Let’s break them down, starting with the systems.

  • Air Compressor – This device takes air from the room and compresses it. By pressurizing the air, the compressor can power different movements and tasks. If the air wasn’t pressurized, the arm wouldn’t be able to move very much, if at all.
  • Air Reservoir – This component stores the compressed air so that the arm can use it. There may be multiple reservoirs within the pneumatic system.
  • Valves – There are usually several valves within the system. These parts control the flow of air through the different reservoirs, allowing the arm to move. The more valves, the more complex the design.
  • Circuit – This component controls the valves, telling them when to open and close. The circuit usually gets its instructions from a computer or other centralized system.
  • Actuator – An actuator converts energy into movement. Each part of the arm (which we’ll discuss next) needs an actuator to perform a specific action. For example, the wrist actuator allows it to rotate and bend.

Now that we know the systems, let’s break down the various parts of the pneumatic robot arm and see how they work together.

  • Shoulder – On a human, the shoulder is just below the neck. For a robot arm, the shoulder is the base component, holding up the rest of the machinery. Like human shoulders, this part can rotate and bend to achieve different movements. This flexibility allows the arm to move along multiple axes as necessary to complete a task.
  • Upper Arm – This section is thicker than the forearm because it moves the rest of the arm. Typically, the upper arm can only move forward and back but not rotate and spin.
  • Elbow – Most pneumatic robot arms only have one elbow, allowing the system to bend. However, specialty arms may have more than one elbow to allow for more complex movement. This is rare, though, because adding extra parts makes the system more complex.
  • Forearm – This part allows the wrist and hand to move into place. It bends at the elbow and can often rotate, much like a human forearm. Again, a wider degree of movement allows the arm to do more complicated tasks.
  • Wrist – This component can rotate and bend, often 360 degrees.
  • Hand – The hand of a pneumatic robot arm varies based on the tasks it’s performing. For example, a hand may be a claw, or it might be a stylus. If workers use the arm for different tasks, they may be able to switch hands as necessary. Usually, a hand is designed for a specific job, such as grabbing.

Pros and Cons of Pneumatic Robot Arms

Although robot arms are helpful for many tasks, they have some substantial limitations. Let’s break down the advantages and disadvantages you can expect from this device.

Pro: Fluid Movements

Because a pneumatic arm uses compressed air, its movements are often smooth and fluid. Gears and other mechanical components can be jerky and stilted, but actuators can precisely control the airflow.

Since pneumatic arms are agile and delicate, they can be used for complex medical procedures or similar tasks.

Con: Lack of Speed Control

Pneumatic robot arms typically go at one speed over and over. While you can adjust the speed setting slightly, the options are much more limited than hydraulic or electrical systems. Since air isn’t solid, it takes longer to compress than liquid.

Pro: Better Safety Protocols

Air compression can enable robot arms to do a lot of tasks, but they’re not super strong like hydraulic or electrical machines. So, the valves and tubes can burst more quickly when put under pressure. This feature is actually beneficial since pneumatic arms have less of a chance of injuring someone while working.

The other advantage is that pneumatic arms use air. So, if there’s a burst or a slow leak, workers don’t have to worry about toxic or flammable gas escaping into the workplace.

Con: High Long-Term Costs

Pneumatic robot arms are appealing to many businesses and operations because they cost a lot less upfront. However, over time, the actuators and tubes will wear down, causing maintenance issues and costs. Overall, high-quality pneumatic arms can last long, but they’re not as efficient or durable as hydraulic models.

Pro: Delicate Movements

Pneumatic arms can be much more precise than hydraulic varieties. So, there are more nuanced applications where a pneumatic arm will work best. That, coupled with a low upfront cost, makes these arms ideal for startups and small businesses.

Con: Moisture Buildup

Compressed air is naturally colder than non-compressed air. So, moisture can build up in the valves and tubes, forcing workers and technicians to flush the system regularly. Otherwise, water can wear out the components or lead to jerky movements.

How are Pneumatic Robot Arms Used?

Understanding how these arms work is one thing – now let’s look at how they’re deployed in real-world settings.

  • Manufacturing – Pneumatic arms are suitable for precise manufacturing processes, such as welding, cutting, and shaping.
  • Food Processing – These arms are much softer than hydraulic models, so they won’t crush or damage food ingredients by accident.
  • Medical – A pneumatic arm’s delicate, softer movements make it ideal for surgery and other healthcare procedures.
  • Construction – As with manufacturing, these arms can perform different tasks like bricklaying or drilling.

Overall, pneumatic robot arms are versatile, cost-effective (mostly), and easy to use. So, you can find them in many applications and industries. The possibilities are practically endless.

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Joshua Garcia, Founder

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