Robots have become an integral part of modern manufacturing processes. Among them, polar robots, with their unique construction, have carved a niche for themselves. As one of the oldest robot designs, these machines have been reliable for certain industries for over 50 years. 

While they’re beginning to be replaced by newer robot designs, there’s still a place for these machines. This article will help you discover the unique benefits of polar robots, understand their role across various industries, and explain which tasks where these robots excel.

What Are Spherical (Polar) Robots?

Polar robots, also known as spherical robots, are characterized by their unique configuration and movement capabilities. They perform three distinct movements: rotation, elevation, and extension from a stationary base–giving them a spherical/polar working envelope.

This configuration grants the robot a wide range of motion and flexibility, making it highly versatile for various tasks. Here's a breakdown of the movements:

• Rotation: The robot can rotate around a vertical axis, which forms the base of the robot. This allows the robot to cover a wide horizontal range around its base.
• Elevation: The robot's arm can move up and down in a vertical plane, enabling it to reach different heights.
• Extension: The robot's arm can extend or retract, moving closer to or farther from the base.

These simplified mechanics combine to give the robot a large work envelope (the total space within which the robot can operate). The shape of this work envelope is a sphere, which is why these robots are sometimes referred to as spherical robots.

The Unique Advantages of Spherical Robots

Each robot design comes with inherent advantages and weaknesses. These features enable robots to specialize in specific tasks or industries. 

Understanding the strengths and shortcomings of spherical robots enable manufacturers to understand the type of tasks for which they can be a good fit. Let’s explore the features and trade-offs offered by these robots.

Advantages

Large Workspace

Polar robots have a broad work envelope due to their spherical coordinate system, enabling them to reach a large area around their base. This makes them ideal for tasks requiring wide coverage–especially those requiring coverage in a circular area.

Efficiency in Circular Motion Tasks

Polar robots excel in tasks requiring circular motion due to their rotational capability. This makes them ideal for applications like palletizing, welding, and machine tending, where circular movements are common.

Precision and Repeatability

Polar robots are known for their accuracy and ability to repeat tasks with minimal variance, making them ideal for tasks requiring high precision. This is largely thanks to their simplified mechanics. Industries with simple tasks that demand high levels of repeatability, such as the automotive industry, find benefits from spherical robots.

Disadvantages of Polar Robots

Complex Controls

The spherical coordinate system used by polar robots can make programming and controlling them more complex than other robots. Therefore, it often requires specialized knowledge and training. This can extend integration time compared to similar but more common robot types like six-axis robots.

Space Requirements

Despite their large work envelope, polar robots can require significant space to operate safely and efficiently. Their mechanics mean the arm requires free space to extend and retract properly. As a result, they may not be suitable for applications in confined spaces.

Limited Payload

Polar robots’ mechanical design limits their payload capacity compared to other robotic configurations. This could be a drawback for tasks that require lifting heavy parts or objects. Depending on the task, manufacturers might benefit from a six-axis or cartesian robot for higher payload applications.

Speed

While precise, polar robots' movement speed can be slower than other robot types like Cartesian or SCARA robots. The trade-off between speed and precision is one that manufacturers must consider before purchasing a robot. Tasks that aren’t as demanding for speed can still be a good fit for spherical robots.

Industries Using Spherical Robots

Polar robots are commonly used in industries where a large workspace and precise movements are required. Below are some sectors where these versatile machines are making significant contributions.

Automotive

Polar robots got their start in the automotive industry. These robots can handle painting, welding, material handling, and inspection tasks. Their combination of reach, precision, and lower cost are enticing for automotive manufacturers. The automotive industry, in particular, has historically used polar robots for tasks like welding and assembly.

Retail Manufacturing

Polar robots are used in simple manufacturing processes that require decent precision and reach. Retail manufacturing applications such as palletizing, packaging, and assembly are a good fit for polar robots. The circular movements and extensive reach are particularly helpful.

Aerospace

The aerospace industry uses polar robots for various tasks, including assembling and testing spacecraft components. The large workspace and precise movements of these robots are ideal for handling the large and intricate components typically found in this industry. Additionally, simple painting and welding tasks common to the aerospace industry can be handled by polar robots.

Education

Polar robots are also used in educational settings, providing students with hands-on experience in robotics. They serve as a simple and cost-effective tool for teaching concepts related to robotic control, programming, and automation.

The Best Applications for Spherical Robots

As general-purpose machines, manufacturers can apply spherical robots to a variety of tasks. Let’s focus on a few common tasks that they’re particularly suited for.

Machine Tending

Machine tending involves loading and unloading machines or moving parts from one stage of a process to another. The wide reach of polar robots allows them to service multiple stations from a single location, loading and staging multiple areas simultaneously. Additionally, their precision ensures that parts are placed correctly, reducing the risk of damage or misalignment.

Welding

The precision and repeatability of polar robots make them ideal for welding tasks. They can maintain a consistent speed and orientation, resulting in high-quality and consistent welds. In addition, the robot's ability to perform circular movements is advantageous in welding tasks that require consistent, smooth circular paths, such as pipe welding in construction or oil and gas industries.

Injection Molding

In injection molding, products must be removed from the mold after they have been formed. This process requires precision to avoid damaging the product or the mold. Spherical robots are well-suited to this task with their accuracy and fast cycle times. In addition, their large work envelope allows them to reach into the mold, retrieve the product, and then move it to another location for further processing or inspection.

What’s next?

While polar robots have demonstrated their versatility and precision in various industries, it's essential to acknowledge the evolving landscape of robotics. Though these robots once held the spotlight for tasks requiring large work envelopes and precise circular motions, advancements in technology have led to the emergence of newer robots that are gradually replacing them. For some applications and industries, there will always be a place for the simple and elegant design of the spherical robot.

Nevertheless, the legacy of polar robots underscores the importance of innovation and adaptability in the world of automation. As we move forward, the key to successful robotic integration lies in understanding our specific needs and aligning them with the capabilities of the most current and suitable robotic technologies.

You may be ready to take the next step toward automating your manufacturing processes, but where do you start?

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