An actuation mechanism for a dual-arm scara-type robot for automated pick-place operations in semiconductor and flatpanel-display manufacturing applications is described. The mechanism consists of a pivoting platform and two linkages coupled to the platform through a pair of revolute joints. The opposite ends of the linkages are connected to the upper arms of the robot by another pair of revolute joints, forming a pair of three-bar mechanisms coupled through the pivoting platform. When the platform is in its neutral position, both of the arms are retracted. The geometry of the components of the mechanism is selected so that rotation of the platform from the neutral position in one direction produces desirable radial motion of one arm while the other arm is kept almost stationary in the retracted position. The arms exchange their roles when the platform rotates from the neutral position in the opposite direction. Alternatively, to achieve absolutely no motion of the retracted arm while the other one extends, the pivoting motion of the platform can be replaced by a rocking arrangement with two pivot points. In this configuration, the locations of the two pivot points coincide with the locations of the revolute joints between the linkages and the upper arms when the platform is in the neutral position. As a result, rotation of the platform with respect to one of the pivot points produces no motion of the corresponding arm while the other one extends. Compared to a conventional design, which utilizes a pair of motors coupled to the robot arms through a pair of belt arrangements, the present mechanism eliminates one of the two motors, including its electronic circuitry, and replaces the belt drives with rigid linkages, thus reducing the complexity and cost, and improving the reliability and cleanliness of the robotic system.

Volume Subject Area:
Dynamic Systems and Control
Topics:
Belts, Design, Geometry, Linkages, Manipulators, Manufacturing, Motors, Reliability, Robotics, Robots, Rotation, Semiconductors (Materials)
1.
Almogy, G., Cluster Tool, U.S. Patent No. US 6,208,751 B1, March 27, 2001.
2.
Beaulieu, D. and Pippins, M. W., Substrate Processing Apparatus Having a Substrate Transport with a Front End Extension and an Internal Substrate Buffer, U.S. Patent No. 5,882,413, March 16, 1999.
3.
Caveney R. T. and Hofmeister C. A., Robot Handling Apparatus, U.S. Patent No. 5,765,983, June 16, 1998.
4.
Davis J. C. and Brooks N. B., Articulated Arm Transfer Device, U.S. Patent No. 4,730,976, March 15, 1988.
5.
Davis J. C. and Hofmeister C. A., Substrate Transport Apparatus with Dual Substrate Holders, U.S. Patent No. 5,647,724, July 15, 1997.
6.
Garriga, R. A., Cluster Tool Architecture for Sulfur Trioxide Processing, U.S. Patent No. US 6,451,118 B1, September 17, 2002.
7.
Hendrickson R. A., Articulated Arm Transfer Device, U.S. Patent No. 5,180,276, January 19, 1993.
8.
Hosek M., Time-Optimum Trajectories for Robots with Multiple End-Effectors, Proceedings of 2003 ASME IMECE, November 16-21, 2003, Washington, DC.
9.
Hosek M. and Elmali H., System of Trajectory Planning for Robotic Manipulators Based on Pre-Defined Time-Optimum Trajectory Shapes, U.S. Patent No. 6,216,058, April 10, 2001.
10.
Hosek, M. and Elmali, H., Time Optimum Trajectory Planning for Cluster Tool Robotic Manipulators, Worldwide Automation and Performance Symposium, October 14-18, 2002, Phoenix, Arizona.
11.
Hosek, M. and Elmali, H., Trajectory Planning and Motion Control Strategies for a Planar Three-Degree-of-Freedom Robotic Arm, U.S. Patent No. 6,643,563, November 4, 2003.
12.
Hosek M. and Valasek M., Three-Degree-of-Freedom Parallel Robot Arm, U.S. Patent Application S/N 10/739,375, filed in 2003.
13.
Lucas B. M., Time Optimal Trajectory for Cluster Tool Robots, U.S. Patent No. 5,655,060, August 5, 1997.
14.
Shiraiwa H., Conveyor Apparatus, U.S. Patent No. 5,404,894, April 11,1995.
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