Types of Inspection robots: Articulated, SCARA, Cartesian, and Cylindrical

Choosing an Inspection robot is all about finding the right robot for the job. The main types are Articulated, SCARA, Cartesian, and Cylindrical robots. Each has its strengths and limitations.

Articulated robots 

Articulated robots have rotary joints which provide a large range of motion, similar to a human arm. Their flexibility makes them suitable for complex inspection tasks across multiple angles and they can easily pick up or manipulate the parts they inspect. However, they tend to be amongst the most expensive choices of robots.

SCARA 

SCARA (Selective Compliance Assembly Robot Arm) robots have two parallel rotary joints and a radial working area. Their rigidity provides high precision and speed for basic inspection jobs with small parts. Although, their limited range of motion is not ideal for intricate inspections or inspecting different angles.

Cartesian robots 

Cartesian robots can move horizontally across a set of tracks. They offer high precision and speed alongside mobile movement. They’re often called gantry robots as they commonly hang from a ceiling gantry. They work great for fast, single-angle inspections, especially on a conveyor-driven production line, but quickly become a complex choice for multi-angle inspection or part manipulation.

Cylindrical robots 

Cylindrical robots have a single rotary joint, allowing for fast, precise rotation of parts. They work incredibly fast for basic visual inspections and defect removal. Unfortunately, their limited degrees of freedom prevent complex part manipulations or multi-angle inspections.

When choosing an Inspection robot, consider the intricacy of parts, inspection angles, precision and speed, working environment, and payload capacity required. You may also want to consider whether or not you need your robot to make decisions via AI or computer vision technologies.

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Inspection capabilities: Visual, Ultrasonic, X-Ray, and Laser

Arguably more important than the specific type of robot is the vision capabilities you need for your inspection capabilities. The availability and quality of each will vary between manufacturers. Let’s explore each capability:

• Visual inspection uses cameras to check for surface defects, color variations, and component presence. Robots with multiple high-resolution cameras at different angles can detect even tiny flaws and make decisions with basic computer vision programming. Paired with end-of-arm-tooling to manipulate parts or advanced AI to detect the slightest of defects, this method of inspection is the most versatile.
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• Ultrasonic inspection uses sound waves to detect subsurface defects like cracks and voids. It requires a robotic arm to move an ultrasonic probe over the area. This type of inspection is particularly useful for welding inspection or checking composite materials and is less prone to false positives than camera-based inspections, but is slower than a visual inspection.
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• X-Ray inspection uses radiation to create images of the internal structure of an object. This type of inspection has an X-ray source and detector mounted on a robotic arm that can check for defects in castings, welds or electronics. X-ray inspections are more thorough than Ultrasonic inspection, but require more advanced programming to interpret any defects. Whilst the radiation won’t pose any problems for your robots, you’ll have to consider the health and safety implications for any workers in proximity to your robots. 
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• Laser inspection uses laser light to scan, map contours, profiles and surfaces in 3D. Laser Inspection robots have a laser range finder, laser line probe and are ideal for inspecting parts with complex geometries for dimensional accuracy. This capability is best paired with a precise robot and whilst not as dangerous to human health as X-ray inspection, does pose some workplace hazards that you’ll need to consider.

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End-effectors and tooling for Inspection robots

With an inspection type chosen, you’ll need to consider the end-of-arm-tooling required to realize the inspection capability. This may be a tool like an ultrasonic probe or a gripper for manipulating the part. Let’s review some of the most common choices:

Camera systems

Inspection robots frequently use camera systems for visual inspection. These can check for surface defects, read text or barcodes, measure parts, and more. Multiple high-resolution cameras are often used together to provide a complete view of the part. Some systems also use 3D cameras to create detailed models of the part that can be measured and analyzed. Some robots, like Standard Bots’ RO1, come equipped with a built-in vision system, but specific inspection applications or less well-equipped robots may require an external camera to be mounted.

Sensors

Inspection robots may utilize various sensors to test part properties. Tactile (or “fingertip force”) sensors can detect dents, scratches, and other surface imperfections. Laser sensors are used for precision measurement of a part's dimensions, profiles, and contours. Ultrasonic sensors can detect internal flaws or defects. Keep in mind that these end-effector sensors may require additional accessories and external power sources to function.

Grippers and manipulators

Grippers allow an Inspection robot to handle and position the part so the cameras and sensors can access all necessary areas. Grippers designed for Inspection robots are typically very dexterous, with multiple articulating fingers for delicate grasping and manipulation of parts. Some use suction or magnetic systems to grip appropriate parts instead of mechanical grippers.

Factors to consider when selecting an Inspection robot

With a type of robot and the necessary end-effectors decided upon, you’ll need to take a closer look at the specific robot brand and model you want for your inspection application. Here are the top factors we recommend paying attention to:

Number of angles

Do you need to look at two different sides of a part? Do you need to rotate a part 360 degrees for a full inspection? Key considerations here are the number of joints in your robot — we almost always recommend a Six-Axis articulated robot for thorough inspection tasks — due to the speed at which they move.

Environment

In what conditions will the robot operate? A robot suitable for a cleanroom will differ from one for outdoor use. Consider space constraints, lighting, temperature, and potential hazards. At a minimum, your manufacturer of choice will be able to provide an IP rating for your robot arm and will be able to recommend appropriate lightning solutions for your working area.

End-effector actuation

Many Inspection robot manufacturers offer systems with interchangeable end-effectors and open connectivity so the robot can be adapted for different uses. Keep in mind that the end-effector will require a separate power source from your chosen robot. Certain end-effectors such as grippers may require a different type of actuation or pneumatic actuation from an attached air compressor. 

Software and integration

Look for a robot with intuitive, user-friendly software to program, operate, and analyze inspection results. Consider how it will integrate with your existing systems and accessories such as conveyors. Some robots offer no-code programming solutions, ideal for high-mix shops where retooling downtime is a challenge, whereas other robots require robotic experts to program them but allow for incredible intricate automation routines as a result.

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Top Inspection robot manufacturers

When choosing an Inspection robot, you have a multitude of options from leading manufacturers like ABB, KUKA, FANUC, and Standard Bots. Each offers various robot models for different inspection needs and has different levels of aftercare service available. 

ABB

ABB is a Swiss pioneer in robotics and automation, with many models used for inspection. Their IRB 360 FlexPicker has a compact design perfect for small parts assembly. The IRB 6640 Robot has a large work envelope ideal for inspecting aircraft components. They offer 2D and 3D vision systems that provide the “eyes” for their robots.

KUKA

KUKA is a German leader in industrial robotics and automation solutions. Their KR AGILUS series is a popular, flexible option for inspection tasks. The KR 10 R1420 Titan KUKA Robot is a heavy-duty model suitable for harsh environments. Like ABB, KUKA also offers 2D and 3D vision and software for vision-guided robotics.

FANUC

Japan-based FANUC is one of the largest robotics companies in the world. Their M-1iA and M-10iA delta robots are fast, precise models ideal for high-speed inspection of small parts. The heavy-duty M-2000iA/1700L robot can handle large payloads for inspecting heavy components. FANUC also provides integrated vision and software to support their robots.

Standard Bots

Standard Bots is a US-based manufacturer of the flagship RO1. With a Six-Axis articulated arm that holds a heavier payload and faster movement than any robot in its competing class. RO1 stands out with an AI-backed vision system for easy inspection, no-code programming capabilities, and an affordable price point starting at $5/hour.

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Next steps

Whether you need a basic visual Inspection bot or a highly dexterous one that can perform complex, multi-angle or 360-degree inspections, there’s an automation solution for you. Take the time to evaluate different options from various vendors to determine what will work best for your specific application. 

Interested in bringing Inspection robots to your own business? RO1 by Standard Bots is the best choice for factories large and small:

1. Affordable: RO1 is the most affordable robotic arm in its class, starting at almost half the price of incumbent competitors. 
2. All-Seeing: RO1 is equipped with best-in-class vision systems. Easy no-code programming makes it easy to detect the smallest of defects and imperfections.
3. Collaborative: RO1 comes equipped with safety sensors and built-in collision detection, for safe operation anywhere on your shop floor.
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Speak to our solutions team today to organize a free, 30-day onsite trial and get expert advice on everything you need to deploy your first robot.