Test Environment for High-Performance Precision Assembly - Development and Preliminary Tests

Abstract

Abstract:This paper presents a test environment enabling the study of factors affecting on the success of a robotic precision assembly work cycle. The developed testing environment measures forces and torques occurring during the assembly, and uses a system based on machine vision to measure the repeatability of work picce positioning. The testing environment is capable of producing exactly known artificial positioning errors in four degrees-offreedom to simulate errors in work-piece positioning accuracy. The testing environment also measures the total duration of the robot work cycle as well as the durations of all essential phases of the work cycle. The testing environment is best suited for light assembly operations and has measurement ranges of *36 N and *0.5 Nm and the vision system has a field-of-view of 6 mm.The latter part of this paper presents the results of the research done in order to find out how some selected factors affect the assembly forces of robotic assembly. These factors include work piece and process parameters such as work piece material and design (chamferedistraight), positioning tolerances, and robot insertion motion speed.

A Classification and Coding System for Micro-Assembly

“…6^^ digit -Specific Stiffness Prusi et al [13] mention that the stiffness of the micro-part is a possible factor affecting the success of a precision assembly work cycle. The Fraunhofer Institute in its 2000 annual report [14] mentions that a high specific stiffness and low specific weight of the micro-parts allows for high dynamics and low power consumption of the drives 46 A Classification and Coding System for Micro-Assembly that actuate the positioning stages.…”

“…Another interesting example of microassembly is a commercial unit by Klocke Nanotechnik with four nanorobotics axes (X, Y, Z-stages plus microgripper) and a joystick, which is capable of carrying out assembly of glass fibers, laser diodes, RF-mixer, micro systems or the handling of thin wires, gears, SMD-chips and micro sensors [3]. Furthermore, considerable research has been done on the development of specific micro-assembly tools and methods including work on visual servoing, sensor-based assembly and a vacuum handling tool [4][5][6][7][8][9][10][11][12][13]. At the micro-assembly systems design and planning level, Kumiawan et al have reported an attempt at developing a morphological classification of hybrid microsystems assembly [4] and several research works dealing with the planning for assembly have also been reported [5][6].…”