I ran into a robot problem at the General Motors Oshawa Truck Plant during the GMT800 Project. One of the engineers was complaining that a robot had positions that were changing randomly. The engineer’s theory was that the robot-controller architecture was flawed, i.e., the entire controller-series design was defective. I had not been on shift when any of the problems happened, but I doubted the controller was the problem.
Then, one day I happened to be on shift when the problem occurred. The robot had been stopped at the corrupt position. After inspecting the situation, the robot was stepped through the program, and the positions were correct. The robot work cell was put back into production, and I watched the cycle for a short time.
Luckily, after a few cycles I noticed the presentation tooling misfeed a part to the robot. I asked the operator to stop the robot, and then I asked a tool maker to inspect the tooling. The tool maker confirmed that the part had been misfed. If the part is presented to the robot incorrectly positioned, it will then be placed in the wrong position. The presentation tooling was adjusted, and I did not hear of that problem again.
This entry was submitted by Glenn Aitchison and edited by Rob Spiegel.
Glenn Aitchison’s first field service job was in 1987. Since then he has worked in robotics, automotive, as well as industrial automation and machinery. He received his Certificates of Qualification as an Industrial Electrician and as an Industrial Mechanic (Millwright).
Tell us your experience in solving a knotty engineering problem. Send stories to Rob Spiegel for Sherlock Ohms.