A new wave of easy-to-use robot vision systems allows companies with no automation experience to enjoy the benefits of vision-powered production. But can these no-fuss, low-cost systems support complex tasks like quality inspection?
Traditional robot vision systems have a well-deserved reputation for being expensive and difficult to operate. Despite the clear benefits of introducing vision to production lines, the cost and complexity associated with traditional systems has understandably discouraged many small-to medium-size businesses (SMBs) from adopting this useful technology.
New collaborative robot-based vision systems are changing all that. Collaborative robots (or cobots) are low-cost industrial robot arms that are easy to use, quick to deploy, and safe to operate in close proximity to humans. When combined with the new generation of easy-to-use robot vision systems using 2.5D cameras, the result is a powerful industrial robot platform that can be used on a wide array of vision-based applications, from part identification and inspection, through pick-and-place and quality control.
The appeal of this new breed of robot vision technologies is based on their ease of use. Advances in industrial computing power and falling camera technology costs make it possible to provide affordable vision hardware but for SMBs, it's the no-fuss way in which these systems are operated that is most transformative. No longer having to rely on expensive robot promgrammers, SMBs can deploy their vision-based cobot applications themselves, using in-house resources and without breaking the bank in terms of capital outlay and ongoing maintenance and programming costs.
Intuitive control applications allow vision-based tasks to be set up within hours, even by users with no prior robotics experience. So, vision-based applications that were once the sole preserve of large companies are for the first time accessible to SMBs as well.
Before we address complex applications, let's take a look at the benefits of robot vision and the key considerations to keep in mind when selecting a vision product for your facility.
Advantages of Robot Vision
Traditional “blind” automation requires complex and costly hardware to perform even the simplest of pick-and-place tasks. The main challenge here is that objects have to be presented to your robots in exactly the same orientation and location every single time, which means installing costly fixtures and fittings — and hardware such as bowl feeders — so that your robots know precisely where the item to be picked is located. If you need to pick and place different objects in different orientations with rapid changeover times when switching between products, then it's time to consider the benefits of adding robot vision to your production lines.
Robot vision eliminates the costs associated with the addition of new hardware and fittings. Robot vision also brings flexibility to your operations, enabling you to switch between different products easily, which is a massive plus for busy manufacturers, especially in today's demanding, customized production environment.
Not all cobot-based vision solutions are the same, however. There are variations in camera technology, expense, and ease of use that can make a huge difference to end users.
Selecting a Camera
At the heart of every vision system is its camera and here there are three main options to consider.
2D cameras are the cheapest available but are also the least versatile. Typically, 2D cameras determine length and width (X and Y axes) but are unable to determine height, which limits the number of applications they can support. On the plus side, they are reliable within these constraints. With some clever mathematics, the performance of 2D cameras can be improved but that tends to be an inconvenient, time-consuming, and somewhat unnecessary process, especially when more capable camera options are readily available.
By contrast, 3D cameras provide your robot with all the visual information it could possibly need, across all three axes and incorporating object rotation. This functionality comes at a price, however, since 3D cameras are the most expensive and also tend to be difficult to integrate and operate. This complexity adds extra cost to 3D-based vision since expensive robot vision experts are often required to program these systems. Furthermore, 3D cameras have reliability issues that make many manufacturers reluctant to embrace the technology, despite its powerhouse capabilities.
2.5D cameras occupy a sweet spot between 2D and 3D cameras, both in terms of cost and capabilities. Capable of determining the height of objects, 2.5D cameras are ideal for scenarios in which objects differ in height and when items need to be stacked. Less expensive than their 3D counterparts and more capable than 2D cameras, 2.5D cameras are an ideal fit for a wide range of applications.
To gain the full benefit of the new generation of vision systems, make sure to look for products that can be mounted externally on your cobot arm. External mounting brings increased versatility to your vision setup, allowing the camera to be mounted anywhere within your production cell. By contrast, some cameras have to be either integrated directly into your robot arm or attached to your robot's wrist to function, limiting their deployment potential.
Besides eliminating the issue of cables running alongside your robot, external mounting also allows end users to optimize cycle time because the vision system can take care of image capture and processing while your robot is busy taking care of another task. Look for systems that provide simple, one-shot calibration, as this eliminates a lot of the time-consuming hassle associated with setting up traditional vision systems.
Simple Technology, Complex Applications
So, you've found the right 2.5D camera-based vision system but can it handle demanding and complex applications such as mobile deployments and quality inspection? It's important to do your research here, since not all 2.5D camera-based systems have the additional software functionality needed to successfully perform complex tasks.
For demanding quality inspection applications, look for solutions that include one-shot detection for multiple objects, and color and blob detection. These features will enable the system to easily sort, inspect, or pick and place unstructured objects. A significant benefit of this detection method is that it finds items based on color and size information input by the operator and requires no workpiece teaching.
Whether you need to inspect parts removed from CNC machines or check IMM parts for excessive or inadequate material after a part has been molded, the latest cobot-friendly vision systems can be set up and deployed with the minimum of difficulty.
For mobile deployments, select vision systems that come with automatic “landmark” calibration tools. Designed to speed cycle time for mobile robot setups, these tools enable easy vision system deployments on mobile robots and setups with carts, trays, and pallets. Landmark features make it simple to program mobile robots to move from station to station. The same features can also be used to initiate specific robot operations; for example, when your vision system detects the arrival of a mobile cart in its workspace loaded with parts for picking, it can easily switch to pick-and-place routines.
Finally, while cobots are a good match for easy-to-use vision systems, consider systems that are compatible with a wide range of cobot and lightweight industrial robot arms. This will greatly increase deployment opportunities within your facility.
For decades, SMBs have been deprived of enjoying the benefits of robot vision. The emergence of a new breed of low-cost, cobot-friendly vision systems, however, is making the technology accessible to small companies for the first time. This new era of robot vision for all presents manufacturers of all sizes with a great opportunity to embrace vision-based automation without all the cost and complexity that usually entails.
This article was written by Kristian Hulgard, general manager, at OnRobot Americas division, Dallas, TX. For more information, visit here .