| dc.description.abstract |
A multi -scale robotic assembly problem is approached here with focus on mechanical design for precision positioning at the microscale . The assembly system is characterized in terms of accuracy /repeatability and calibration via experiments . The MEMS packaging requirements are studied from an assembly point of view . The tolerance budget of the assembly ranges from 4 microns to 300 microns . The system components include robots , microstages , end -effectors and fixtures that accomplish the assembly tasks . Task assignment amongst this hardware has been accomplished based on precision and dexterity availability . Various end -effectors and fixtures have been designed for use with off -the -shelf hardware (robots and microstages ) to develop a coarse -fine positioning system . These end -effector and fixture designs are tested for precision performance . The robots and the vision system are calibrated to an accuracy of 11 microns or less . Inverse kinematics solutions for one of the robots have been developed in order to position parts in the global coordinate frame . Conclusions have been drawn with regard to implementation of calibration , fixturing , visual servoing or a combination of these techniques to achieve assembly within the specified tolerance budget as required by the target application . End -effector performance is improved by tuning the PID gains of the controller such that tool oscillations are minimized . |
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