In short
Toyota Motor Hokkaido, Inc., which manufactures transmissions, axles, and other parts for Toyota vehicles in Tomakomai, Hokkaido in Japan has “strengthening the manufacturing structure” as a major goal. The company began building a robot system using UR cobots to improve its facilities for the diff-pinion (round gear wheels) loading process, which had been a challenge. As a result, they were able to build their own robot system that reduced costs and space, and improved the operation rate from 92% to 98%, compared to the previous system.
In the process of feeding a diff-pinion into a processing machine, the operator lifts up a skewer with multiple diff-pinions skewered on it and sets it on the transfer machine on its side, and the workpiece is fed into the machine under its own weight. The equipment had to be modified each time the shape of the workpiece changed, and the skewered workpiece weighed 2 to 3 kg, placing a heavy burden on the operator who had to work carefully to avoid damaging the workpiece.
How they did it
Junichi Isobe, Head of HEVG Group, Unit Manufacturing Engineer Office, Engineering Department of Toyota Motor Hokkaido, says, “We wanted to improve our own processes based on our goal to strengthen our manufacturing structure, and were introduced to UR cobots by our distributor, Toyoda Yuki. After seeing the growing popularity of collaborative robots at the International Robot Exhibition in December 2019 and the ROBODEX Exhibition in January 2020, we decided to take on the challenge.”
The challenge in introducing a cobot for the first time was to keep the cycle time within the prescribed time and to find a way to recognize the workpiece. A vision camera would exceed the cycle time and it would be difficult to detect the workpiece because it is shiny black. Therefore, Toyoda Yuki devised a method that utilizes the UR cobot’s built-in force torque sensor (F/T sensor) to detect the workpiece when the gripper hits the workpiece. This method was adopted after a demonstration test. Syusaku Jin, Unit Manufacturing Engineering Department, HEVG, Engineering Division says: “We decided to develop a system without a camera, that simplifies system configuration. The grippers are OnRobot’s RG2 and RG6, which are UR+ products, so they were easily programmed on the UR cobot’s teach pendant, as well as the cobot’s built-in F/T sensor.”
