Robots are used in a wide variety of industries for a broad range of applications, from automotive, foundry, and general industry to material handling, packaging, and palletizing. With rising costs, increased competition, and skilled worker shortage, companies are searching for ways to achieve new levels of manufacturing efficiency and profitability, including utilizing robots for tasks not possible before.
Robots are given more ability with vision-guided robotics (VGR), which uses digital imaging and intelligent software to give robots the ability to “see,” “comprehend,” and “reason.” Advancements in computing, sensing, and software make VGR a viable technology to expand the application range of industrial robots.
Traditional vs. Vision-Guided Robotics
Traditionally, robots execute static instructions, performing tasks with a repeatable motion and relying on fixturing to make sure parts arrive at a pre-trained position, limiting some applications. Manufacturers must rely on precision conveyors, pallets, lift-and-locate devices, and precision-manufactured bins and racks, decreasing the return on investment (ROI) for automation projects.
VGR systems efficiently see and react in a changing factory environment — locating, inspecting, handling, transferring, and assembling — all in a fully automated, flexible, and accurate manner.
VGRs utilize cameras and intelligent software to give robots information about their environment, such as location, orientation, and type of parts; quality attributes and features of parts; and the relationship among parts, robots, and other objects. A vision-guided robot is able to react in real time without the need for peripheral equipment, custom tooling, positioners, or precision pins.
Vision-guided robots rely on a camera to capture a single image, which is analyzed to create a complete three-dimensional (3D) position (x, y, and z) and orientation (roll, pitch, and yaw angles) of the part. The 3D position is transmitted to the robot controller, allowing the controller to adjust the robot’s path, including approach and grasp points, to match the location of the given part.
Benefits and Applications of VGRs
VGR systems offer a number of benefits, including increased flexibility by adjusting the variations — in part position, type, style, and quality — in real time, allowing the processing of multiple part types and styles on the same line without the need to re-tool.
VGR also offers improved quality by preventing damage and contamination caused by manual handling, detecting defects through inline automated visual inspection of every part, and significantly reducing process variability.
In addition, there are reduced capital, operational, and ergonomic costs by eliminating precision fixtures, dunnages, and other custom positioning devices; increasing equipment utilization (the same robot is used to process multiple part styles without added investment); and reallocating labor to more human productive tasks, thereby eliminating ergonomic issues.
Adoption of VGR systems has been steadily increasing, particularly in material handling where fixturing typically is more expensive and sometimes impossible due to parts being housed in mobile containers. One of the biggest obstacles to adoption is a lack of end-user awareness of the value of the technology. Many place VGR in the same category as machine vision inspection because both use cameras and imaging. But, there are many differences between the two. Machine vision inspection provides manufacturers with better-quality products, but the parts typically are fixtured or their movement is heavily restricted.
The technology is best suited for applications where parts previously needed to be pre-positioned in order to enable a robot to perform a task on them, or where a robot could not be deployed because fixturing was not feasible such as removal of parts from bins, parts assembly, sealing, and adhesive dispensing.
VGR is ideal for applications involving rigid objects such as plastics and metal. Floppy objects like blow-molded vessels, cloth, or foam are more challenging for vision-guided robots. In addition, vision-guided robots are not ideal for extreme environments with a lot of debris or high temperature or humidity because of potential camera or lighting issues.
When to Choose a VGR
Examine ROI to carefully determine where the most savings can be realized. Benchmark similar applications in the industry to become familiar with the technology and its strengths and limitations. Select a supplier that can provide standard, engineered VGR solutions targeted at solving specific applications.
VGR allows manufacturers to achieve new levels of manufacturing efficiency and profitability, ranging from more flexible production systems and fabrication of higher-quality products to lower capital costs and lower labor and labor-related costs.
Consider the following to determine if VGR is an appropriate solution:
- How much is spent on fixturing parts or specialized containers and racks to make sure parts are pre-positioned for robots? What would the savings be if they could be eliminated or simplified?
- Are there labor-intensive, highly ergonomic injury processes in the operation that could not be automated in the past due to infeasibility of fixturing? What would the savings be if they could be automated?
- Is the capital equipment investment in place now providing all of the benefits possible? How much more productivity could be achieved if one, two, or three other part styles could be run down the same line?
In many cases, return on investment for a typical VGR system — including labor savings in cases where the vision solution enables a manufacturer to automate ergonomics, safety, and quality — can be seen in six months. In addition, there is an instant ROI when expensive fixturing or positioning devices are eliminated from the list of capital equipment.