History of Robotics Research and Development of Japan1975BusinessIntelligent arc welding robot “Mr. AROS”

Akira Tsuchihashi	Hitachi, Ltd.
Takashi Kogawa	Hitachi, Ltd.
Shimon Ando	Hitachi, Ltd.
Norihisa Miyake	Hitachi, Ltd.

Industrial Robots had rapidly been spread into market from around 1970s, when the typical application was spot welding for the automotive industry. Automation of arc welding, which requires continuous path control, had been delayed due to the complexity of path teaching and the difficulty of individual error correction of workpieces. In 1975, an intelligent arc welding robot named “Mr. AROS: Arc welding Robot with Sensors”, promptly adopting a microcomputer which began to appear on the market at that time, as well as employing non-contact distance sensors, has been developed and commercialized to solve these problems[1][3]. 1. Overall specifications: The rectangular coordinate system configuration, with a two degree-of-freedom wrist, driven　by electro-hydraulic servo control mechanism. 2. Sensors: Two eddy current type distance sensors, less affected by heat or light that are specific to arc welding,　enable to detect the relative position between the welding torch and the work piece. 3. Characteristic Functions [2]: ・Interpolation and Coordinate transformation: Only representative points on the path have to be taught as with the PTP (Point to Point) method. CP (Continuous Path) motion of the tip of the welding torch is realized by interpolating the teaching points and to calculate and control position of each axis of the robot. ・Sense function: Utilizing the sensors, the weld line position is automatically detected by simply positioning the welding torch in the vicinity of the teaching points. ・Check function: Utilizing the sensors, the position of representative teaching points are self-searched, and the position of the teaching points are automatically corrected. ・Corner point coordinate calculation: Position coordinates of the corner point, intersection of two straight lines, are automatically calculated from the position of the teaching points corrected by using the check function. ・Profile following control: Online motion trajectory correction control utilizing the sensors. An intelligent arc welding robot, featured by significantly easier path teaching, as well as adaptable to the positioning error and shape error of the workpieces, has been realized with these functions. While it is currently not uncommon as the functions for industrial robots, it can be said as a breakthrough for its time. Thus, the robot is awarded the Nikkan Kogyo Shinbun (Daily Industrial Newspaper)’s Ten Best New Product Award, and Design Award of the same newspaper, both for fiscal 1975. Also, there are gantry type welding robots for large structures, a multipass welding robot for saddle-shaped branch pipe of the pressure vessels[4], as a series product of this robot.

写真1　知能アーク溶接ロボットミスターアロス — Fig.1 Intelligent arc welding robot

記事はありません。

Related Article