Pneumatic vs Hydraulic: Which system is right for your robot

November 28, 2023
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What is Pneumatic Actuation?

Pneumatic systems are all about using air to do the work. Picture a system that operates like your lungs, inhaling and exhaling. However, instead of breathing, it's powering machines.

At the heart of a pneumatic system is compressed air. This air is stored under pressure and then released to create movement or force. It's a bit like blowing up a balloon and then letting it go. The air rushes out and propels the balloon forward.

When it comes to pneumatic machines, this principle is used to perform various tasks. The compressed air is directed through valves and tubes, pushing against pistons or gears to create motion. This is how a pneumatic system can lift, push, or pull without any physical effort from a person.

It's a simple yet effective way to power everything from small tools to large industrial machinery. Using the power of air, work is made easier and more efficient.

What is Hydraulic Actuation?

Hydraulic systems operate in a way that's quite different from their pneumatic counterparts. At the core of a hydraulic system is hydraulic fluid, usually mineral or hydraulic oil, which is used to transmit power.

Unlike pneumatic systems that use air, hydraulic systems rely on fluid to move and control machinery.

What often distinguishes hydraulic systems is their ability to generate immense force through the compressibility of liquids. When pressure is applied to hydraulic fluid in a confined space, it results in a powerful, controlled movement. This is the principle behind fluid power systems - using liquid under pressure to perform work.

In practical terms, hydraulic systems are found in many heavy-duty and industrial applications, such as construction equipment and manufacturing machinery, providing force and precision. It's also worth noting that hydraulic fluid helps with power transmission as well as component lubrication and cooling, which is why it's a versatile solution for demanding tasks.

Key differences


Hydraulic and pneumatic systems differ significantly in power. Hydraulics rely on fluid power to generate a larger force, making them ideal for heavy lifting and high-pressure tasks. Pneumatic systems, although efficient, usually offer less force, so they're generally suited for lighter operations.


When it comes to speed, pneumatic equipment generally outperforms hydraulic systems. The rapid compression and release of air in pneumatic systems allows for quicker movement. Hydraulic systems, despite their power, often operate at a slower pace because of the viscosity of hydraulic fluids.


Pneumatic systems have fewer moving parts and are less vulnerable to contamination, which typically gives them a longer lifespan. Hydraulic systems, on the other hand, can suffer wear and tear due to the continuous movement of hydraulic fluids.

System complexity

Compared to pneumatic operations, hydraulic systems are more complex. They have an extensive network of pumps, valves, and fluid reservoirs. Pneumatic systems are simpler, mainly involving an air compressor, cylinders, and tubing.

Installation and maintenance

The installation of pneumatic systems is generally straightforward and cost-effective. They're also easier to maintain because of the system's simplicity. Hydraulic systems need more intricate installation and regular maintenance to manage fluid levels and prevent leaks.

Environmental impact and safety

Pneumatic actuators are considered safer and more environmentally friendly. They eliminate the risk of dangerous fluid leaks, unlike hydraulic systems where leaks can pose environmental and safety risks.

Energy efficiency and operating costs

Pneumatic systems are generally more energy-efficient, with a lower operating cost. They use air, which is abundant and free, whereas hydraulic systems depend on expensive fluids for their power systems.

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Which method is best?

Deciding whether a hydraulic or pneumatic system is best for your needs mainly depends on the specific use cases and project requirements.

For tasks involving heavy equipment, hydraulic systems are often the more suitable choice. Their ability to generate greater force makes them ideal for applications like construction machinery or industrial lifting. You will see the power of hydraulic-powered machines in scenarios where moving heavier loads is a priority.

However, there's always the potential for hydraulic oil leaks, which can be an environmental safety and maintenance concern.

On the other hand, pneumatic systems shine in cases where speed and efficiency are key. You'll regularly find pneumatic cylinders used in assembly lines and manufacturing processes where fast, repetitive motions are required. These systems are less suited for heavy-duty tasks but do well when operations need agility and precision.

In environments where cleanliness is vital, like pharmaceuticals or food processing, pneumatics are often preferred because there is no risk of leaking hydraulic fluids. Also, pneumatic systems do well in smaller-scale operations where installation space is limited.

At the end of the day, the "best" method will always depend on the specific demands of your application, balancing factors like power needs, the operational environment, and maintenance considerations.


How does an actuator fail?

Actuators can fail for a variety of reasons, like incorrect sizing, improper installation, and excessive loading. Overloading and exposure to harsh conditions are common culprits. Regular maintenance and correct usage are key to preventing actuator failures.

What are the two types of pneumatic systems?

Pneumatic systems are primarily categorized into two types: displacement and dynamic. The displacement type uses compressed air directly, whereas the dynamic type converts the air's velocity into pressure. Each type serves different purposes.

What are the disadvantages of a pneumatic system?

They can be less efficient due to air compressibility which can lead to energy loss. Also, achieving precise control can be challenging. The need for an air compressor and the noise it makes are additional disadvantages to consider.

Which is more expensive, a pneumatic or hydraulic system?

Pneumatic systems are generally less expensive than hydraulic ones. In fact, they usually cost about half as much, mainly because hydraulic machines require more components and maintenance. Hydraulics also have extra expenses like hydraulic fluids and the management of complications with internal parts.

Final thoughts

When you're making a hefty investment in either a pneumatic or hydraulic system, you need to consider your individual needs. The pneumatic vs hydraulic debate isn't about technology, it's about the right fit for your task.

Pneumatic systems offer simplicity and speed, which are ideal for lighter, repetitive tasks. Hydraulic systems, on the other hand, provide the power needed for heavier operations.

Remember, hydraulic and pneumatic machines each have their unique strengths. Consider your application's requirements carefully to ensure you make the most suitable choice for your project.

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