Design and test of a piezoelectric-actuated BioCM-based flying vision system for the LDI machine

Abstract

The LDI machine possesses multiple advantages during the manufacture of printed circuit boards (PCBs). Before the digital exposure procedure, a vision system calibrates the PCB to guarantee enough accuracy. Unfortunately, the current vision employs a rigid-mechanism-based (RM-based) fixed bracket and single-step fixed-vision controller. To improve the imaging efficiency, a flying-vision controller is proposed to replace the traditional fixed-vision controller. To enhance the imaging robustness, a piezoelectric-actuated compliant-mechanism-based (CM-based) adjustable bracket is designed to replace the current RM-based unadjustable bracket. Furthermore, kangaroo legs inspire the increase of the magnification ratio of the piezoelectric-actuated CM. Flea legs are referenced to alleviate the stress concentration of the CM during high-frequency dynamic flying-vision tasks. Then a bioinspired-CM-based (BioCM-based) flying vision system is proposed in this paper. Statics analysis of the BioCM was performed using the finite element method based on the compliance matrix method. Dynamics results were also confirmed. A flying-vision controller was developed. A prototype of the BioCM-based flying vision system was fabricated and tested. The flying vision tests were also carried out inside the LDI machine. Test results demonstrate the robustness and effectiveness of the proposed BioCM-based flying-vision system. Under out-of-focus-plane (OFP) disturbances of three frequencies and five amplitudes, the recognition accuracy of the BioCM-based flying-vision system improved by 13.61%, and the recognition efficiency of the flying-vision controller increased 13.86%. This paper contributes to developing a next-generation LDI machine for high-density interconnected PCBs.