Automating an assembly line that depends on randomly placed components in shipping racks, or autoracking, is among the most difficult automation tasks facing industry today. After evaluating several vision systems for robot guidance, automation specialist Comau Pico (Southfield, MI) purchased 20 of ISRA Vision's MONO3D vision systems. Each system includes cameras, cabling, LED lights, and MONO3D software running on an ISRA Vision controller. The machine vision systems are being used to automate body shop operations at two North American automotive manufacturing locations.
"These systems will be used to remove sheet metal parts from racks for placement into fixtures for the assembly of the car body, eliminating manual load," says Kevin Taylor, ISRA's national sales manager for North America. "MONO3D's small footprint enables the cameras and lights to be mounted on the robot end effector to improve the overall accuracy of robot guidance solution. MONO3D will locate the part in 6 degrees of freedom using predefined part features such as holes or edges, and guide the robot to the part in 3D space."
ISRA Vision released MONO3D in early 2004 in response to customer requests for a more cost-effective 3D automated machine vision system with a smaller footprint for robot guidance, 3D inspection, and similar applications. MONO3D requires only one camera to measure multiple points in the camera's 3D field of view with accuracy and speed comparable to more expensive laser-based and multicamera-based 3D machine vision systems. With large parts, multiple cameras can be used to determine the object's 3D location, providing considerable speed and cost savings when compared to traditional stereovision systems, which would require multiple cameras for each field of view.
How the System Works
MONO3D extracts 3D location data by locating three or more features in an image, determining the spatial relationships between those features, and comparing that information to stored 3D models based on CAD data. The system can precisely establish all 6 degrees of freedom (position and orientation) of any point within the camera's field of view.
This approach reduces not only outlay for equipment, but also the cost of installation, calibration, and operation. MONO3D's single camera approach and flexibility enable more efficient image processing, reducing hardware costs on both the acquisition and processing ends of the machine vision system, while allowing customers to improve throughput based on the specific needs of the application. MONO3D's easy configurability gives the user maximum flexibility to determine spatial resolution, speed, and throughput by accommodating a virtually unlimited number of additional features into its calculations or by limiting the 3D vision to 2D or 2.5 D (x, y, rotation, and a scaling of z), depending on the needs of the application.
The simplicity of the system was one of several reasons Comau Pico chose MONO3D, says ISRA's Taylor.
"We offered a solution that was affordable, technically superior, and very robust," Taylor noted. "We demonstrated the advantages of our standard robot guidance software, which can be applied to 2D, 2.5D, and 3D applications throughout the automotive manufacturing process. ISRA also has a strong global presence, which allows us to offer our customers proven products to standardize applications at their facilities throughout the world."
The software can be applied to automation applications in multiple industries, including robot guidance, automotive, medical, semiconductor, durable goods, and R & D. It can be integrated into many production processes and is suitable for all industrial robot vision and 3D measurement applications, from micro to macro scale, where the position of the workpieces must be determined in 3D and with up to 6 degrees of freedom.
