Robotic Vision System Helps Train Engineers
Four years ago two engineering instructors at Pennsylvania State University at McKeesport, Pa., wanted a project that would get students in their classes to work together. Their students are enrolled in a special two-year, associate degree program for either electrical- or mechanical-engineering technology at the college.
Merwin L. Weed, associate professor of enginereing, and Joseph W. Schaad, an assistant professor of engineering, finalized on the idea of having thier students cooperate on the construction of a computer-controlled drilling machine.
Required components for such a machine were relatively easy to come by and cot little. All that was needed was a drill, a computer, a joystick, some software, and a device called a Unislide, basically a long, metal track with a slide controlled by a stepper-motor. The drilling machine was to be able to punch a programmable X-Y-Z pattern of holes in a 11" x 17" printed circuit board, repeatedly.
The joystick controlled the pattern of the holes; the Unislide moved the circuit board in the desired directions; and the drill drilled. Electrical engineering students did all the software programming, and mechanical engineering students handled the mechanical aspects. Duration of the project from start to finish--two weeks.
Deemed a success by both the instructors and the students, the cooperative learning project continued the next year. Schaad and Weed had their electrical and mechanical engineering students design and build a conveyer belt for the drilling system.
"The idea came from a Rhino [Robots, Inc.] show," recalls Weed. "But the students built the thing mostly from stuff that was just lying around." The rollers were skateboard wheels; the belt was from a vacuum cleaner; etc. A motor to drive the conveyer was purchased. Having met the instructors' original goal of bringing the two engineering disciplines together, now the project was evolving into something more.
That something more turned out to be a full-fledged CIM workcell. In the third consecutie year of the project, Schaad's and Weed's students changed the drilling machine to a milling machine and added even more components. A robot was bought from Rhino Robots, Inc. and incorporated into the system as was a feeding unit.
According to Schaad the workcell's operation was as follows: The feeder fed blanks of machinable-wax plates onto the conveyer. Tripping an eyebeam would stop the conveyer, at which point the robot would pick up the piece and put it into the milling machine. The milling machine would engrave the blank plates with three letters, which had been chosen by the students and programmed into the computer. The robot would then take the finished piece out of the milling machine.
At this point, the system comprised two IBM PC computers--one to onversee the milling tasks and one to control the robot; a feeder; a conveyer belt; the piece-handling robot; and a Westinghouse programmable logic controller (PLC). …