More powerful and accurate cameras are a boon to end-users of industrial robotics. Vision guidance systems are able to capture very accurate three-dimensional locations with just one camera according to Doug Erlemann, Business Development Manager with Baumer Ltd. (Southington, Conn.). Erlemann sees more accurate software, more rugged equipment and cameras with features that alleviate lighting problems. Cameras with automatic gain are more accurate and robust. Vision guidance systems take into account more than just vision calculations and robot calculations, but are tied together in the overall system.
Likewise, Brian Carpenter, Software Engineer with Kawasaki Robotics (USA) Inc. (Wixom, Mich.), sees more accurate vision guidance systems for robotics. He states that, recently, more single camera three-dimensional systems are available. Resolution and accuracy improvements to stereoscopic systems have increased and do not require calibration and can accommodate different working distances.
Mr. Carpenter says that stereoscopic vision guidance systems allow more precise depth measurement. Camera systems are capable of locating objects as well as tracking and predicting their location while moving.
Vision guidance systems are utilized by end-users as a feedback device for generating very accurate frames and tools. Robot-mounted cameras and the images they generate refine an object's position through triangulation, providing for tremendous accuracies. Robots operating within six degrees of freedom are a perfect match with three-dimensional vision-guided solutions.
Due to increasing economic demand and competition, manufacturers are producing products at higher and higher rates. In order to keep up with these increasing production rates, robotic solutions must provide efficient ways to transfer products at the end of the production process from a randomly distributed condition into a sorted condition.
Steve Prehn, Vision Product Manager at FANUC Robotics America Corp. (Rochester Hills, Mich.), states that robust locational systems have the flexibility to quickly adapt to new parts as they are presented to the robot and provide accurate results to have them engage with new parts. Increased processing power allows integrators to go after markets that would be too difficult otherwise.
Assembly applications on the micro and nano-levels are among the new markets for robotics served by enhancements to vision guidance systems. Guidance systems accurately locate very small objects or zoom in to validate positions very precisely. When looking at very small fields of view, resolution goes to the micron range. Mr. Prehn notes that end-users use vision guidance systems to validate and correct for positional inaccuracies over the robot's working area.
Charles Ridley, Material Handling Service Manager with PAR Systems Inc. (Shoreview, Minn.) also talks about the role of robotic vision guidance systems in micro-assembly applications. He states that the challenges with micro-assembly are similar to other robotic vision applications. Ensuring that the robot chosen for the application has the repeatability and accuracy to handle the tolerances that come with a micro application is key. The vision guidance system must have a higher resolution.
Vision guidance systems require calibration with the robot to ensure proper positioning when that robot performs its tasks, says Greg Garmann, Technology Advancement Manager with Yaskawa America Inc.'s Motoman Robotics Division (Miamisburg, Ohio). He states that calibrating multiple camera systems between the robotic space and the vision space so that the robot can understand what the vision camera sees is important. Many applications require variable focal lengths and end-users want automatic focus to determine the depth or distance the guidance camera is from objects.
Garmann comments that end-users must recalibrate the vision system occasionally. When the focus is changed, that also changes the field of view and the calibration of the camera system to the robot. End-users want automatic focus so the guidance system can understand different focal lengths.
Calibration issues are important to end-users of Comau Robotics' systems (Southfield, Mich.) says Process Technology Director, Joe Cyrek. With advancements in computing power, systems allow for robot guidance in six degrees of freedom with one camera and cable without calibration. That advancement is significant. Cyrek adds that end-users want no calibration and simplicity in vision guidance systems. A single camera, cable, a simple interface without the need for calibration equals increased mean time between failures and decreased mean time to recovery, and fast set up.
Cyrek comments that algorithms and their application into robot guidance solutions have changed the perception of robot guidance from complicated to simple, allowing for more ways to use it.
Nicholas Hunt of Automotive Technology Support Group Manager at ABB Inc. (Auburn Hills, Mich.) states that he sees more light with structured wavefronts coming of age for three-dimensional surface scanning applications. The result requires processing massive amounts of data very quickly. New processors provide the necessary speed to fit the demands of production throughput. Hunt stresses the need for good calibration between the robot tool center point and the camera, or calibration between the camera and the work cell.
Thus, many robotic sorting applications currently use machine vision technology to scan a product's orientation on a moving transport surface or conveyer. The machine vision software and controller provide information to the robot controller to instruct the robot to re-orient the product in a desired position. This new re-oriented position is more conducive to packaging or further production processes that will need to take place prior to shipping the product to market.
While the use of machine vision technology is not new, it has traditionally been used for moving individual products on each robot transfer cycle. Any recent attempts to transfer multiple randomly placed items in a single transfer and re-orient them into a more easily manipulated fashion have failed to keep end effector weight to acceptable levels that still allow maintaining high robot transfer speeds.
The advantage of success in producing such a light-weight system would be to reduce the number of time consuming robot cycles between each pick and place. By first picking several products prior to transferring them to the receptacle into a sorted condition can significantly reduce robot transfer time. Large production cost savings can result.
None of the prior devices allow for the efficient transfer of multiple randomly placed items in a weight-manageable single transfer and re-orientation of them into a more easily manipulated fashion. Thus an end effector tool solving the aforementioned problems is desired.