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Pneumatic Basics: Understanding Pneumatic Systems in Robotics, Lifts, and Automation
2024-12-30 | By Don Wilcher
Pneumatics is an engineering field focused on using compressed air or gas to create mechanical motion. Here, the compressed air or gas is directed through various channels to drive mechanical components, like cylinders, actuators, and valves. Pneumatics offer multiple benefits—including simplicity, cost-effectiveness, and reliability—making them useful in a variety of applications, from simple hand tools to complex automated machinery. By converting stored potential air pressure into kinetic energy, pneumatic systems generate movement in applications that require speed and precision. This tutorial will cover the fundamentals of pneumatics, exploring its use in robotics, lifting mechanisms, and automation. In addition, we’ll address key factors to consider when designing pneumatic systems.
Variety of pneumatic components
Basics of Pneumatic Systems
Pneumatic systems use compressed air stored in tanks, which is directed through controlled pathways to perform tasks—such as moving an actuator (like an air cylinder) or driving a rotary device. A standard pneumatic system includes several essential components: the compressor (for air compression), receiver air tank (to store the compressed air), and valves to regulate airflow and direction. Actuators like air cylinders or motors convert pneumatic energy into motion. This motion can be linear or rotary. Flexible tubing is used to connect each pneumatic part, allowing airflow through the energized system. Unlike hydraulic systems, which use liquid, pneumatics relies on air, creating more accessibility and reduced maintenance requirements. These mechanical components work together to deliver controlled power and motion, establishing the foundation for most pneumatic applications.
A basic pneumatic system
Pneumatic Key Concepts
Designing effective pneumatic systems requires an understanding of key concepts such as pressure, flow rate, and force generation. Pressure is the force exerted by the air per unit area. Here, the unit of measurement for pressure (p) is in pounds per square inch (psi). Pressure determines the available power in a pneumatic system. The flow rate is the volume of air moving through the system per unit time. The flow rate influences the speed of an actuator, which is important for tasks where timing and precision are needed in a pneumatic system.
Pascal’s Law states that pressure applied to a confined area is transmitted equally in all directions. This means that pneumatic systems can reliably apply consistent force at all points within the system. Mathematically, Pascal’s Law is expressed as p = F/ A. The variable (p) is in psi, force (f) is in pounds, and the area (A) is in square inches. The force from pneumatic actuators relies on the system pressure and the size of the actuator. This makes it easy to control how the system works.
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Volume plays an important role in pneumatic cylinder component design
Pneumatics in Robotics
Pneumatic systems are widely used in robotics, especially for repetitive tasks requiring speed and efficiency. Pneumatic actuators like air cylinders and motors are well-suited for robots designed to perform simple tasks like pick-and-place operations. Pick-and-place operations require quick response of pneumatic actuators to retrieve electronic components from a reel and place them correctly onto a printed circuit board (PCB). Such systems use pneumatic grippers, which are powered by small air pistons that provide clamping force to hold or release objects. Compressed air flows through valves that control the movement of the gripper’s jaws, allowing the robot to grasp, manipulate, and release objects with precision. Robotics applications also benefit from the reliability, simplicity, and cost-effectiveness of pneumatic systems, making them ideal for many industrial environments.
A pneumatic robot example. Image courtesy of USABOTICS
Advantages of Pneumatic Grippers in Robotics
The main advantages of using pneumatic grippers or end effectors in robotics include rapid actuation speed and low maintenance requirements. Pneumatic systems can respond rapidly, allowing robots to complete tasks faster than using many hydraulic or electric actuators. Additionally, pneumatic systems allow for precise force control by adjusting the airflow using flow control valves. This allows enough versatility to handle both delicate and heavy objects. Pneumatic systems have fewer moving parts compared to hydraulic systems, which means less maintenance and longer life in industrial settings. As a result, pneumatic systems are commonly found in manufacturing and assembly lines where repetitive and reliable motion is required.
A pneumatic robot gripper.
Challenges in Robotics Applications
There are several challenges that can impact the use of pneumatics in high-demanding robotics applications—these include precision machine tooling and fabrication. The compressibility of air can introduce slight variability in actuator position, which may limit its usefulness in tasks requiring sub-millimeter accuracy. Notably, machine tooling and fabrication operations require sub-millimeter accuracy in the areas of assembly and positioning of small fasteners. Robotics used in electronics assembly often require the high precision available by electric-based motor systems rather than pneumatics. Pneumatic systems may require additional control systems to stabilize and dampen movement, which can increase costs and complexity. Despite these limitations, pneumatics remains a dependable choice for many robotic applications, particularly where speed, simplicity, and cost savings are more important than precise accuracy.
A pick-and-place robot. Image courtesy of Engineering Printing Solutions
Pneumatics in Lifting Mechanisms
In lifting applications, pneumatic systems are invaluable for their simplicity, safety, and efficiency. Pneumatic lifts are common in industries such as automotive repair, material handling, and warehouse operations, providing a convenient solution for moving objects vertically. An example of a pneumatic lifting device is the pneumatic scissor lift, which uses air cylinders to raise and lower a platform. The lift’s crisscrossed structure and folding supports extend when air is channeled into the cylinders—this elevates the platform and also retracts when air is released to bring the platform down. Such air-driven mechanisms are designed for controlled, smooth lifting and lowering, making them ideal for applications that demand stability and ease of use.
A pneumatic lift. Image courtesy of Vestil
Pneumatics in Automation Applications
Aside from robotics and lifting mechanisms, pneumatic systems play an important role in industrial automation, powering applications that demand efficiency, repeatability, and low maintenance. From conveyor belts to sorting machinery, pneumatic systems drive numerous automated processes that rely on predictable, controlled movement. Conveying systems are used in material handling to move material over short distances. These systems use compressed air through tubes or flexible hoses to create an air cushion. This air cushion floats the material along a non-contact path for moving items from between locations. In this context, pneumatic automation is especially popular in manufacturing sectors like packaging and food processing, as it provides both speed and gentle handling.
A pneumatic conveying system. Image courtesy of Shalimar Engineering
Pneumatic Systems Design Considerations
Designing a pneumatic system requires an understanding of mechanical component specifications and careful planning to ensure efficient and safe operation. Choosing the right compressor is essential, as it must provide sufficient pressure and airflow to meet an application’s needs. It’s important to consider pneumatic valve size, as flow control valves need the capability of handling system pressure and flow requirements. Pneumatic cylinder and motor size should be calculated based on the force requirements, ensuring they can deliver adequate power without excessive air consumption. Furthermore, flexible tubing, air hoses, and fittings need to be selected for durability, as improper materials can lead to leaks or ruptures under high pressure. In addition, it is essential to incorporate safety mechanisms, such as pressure relief valves and emergency shutoff options, to ensure a safe pneumatic system.
Ensuring Proper Pneumatic Application
Pneumatic components are becoming more prevalent in robotics, industrial machines, and automation systems. Their cost-effectiveness, low maintenance, and quick motion responses make them highly appealing when designing mechanical systems. It's important to consider system design elements to select optimal pneumatic components for the application.
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