Enhanced Attractive Force via Tip Rotatability in Beam-Type Electrostatic Chuck for Advanced Robotic Applications

This study elucidates the enhancement of attractive force achieved through tip rotatability in beam-type electrostatic chucks (BESCs). Both analytical and experimental validations demonstrate a significant increase in attractive force with improved tip rotatability. This advancement is pivotal for achieving reliable, repeatable, and non-destructive large-scale thin-film manipulation, with potential applications in automated robotics systems within the semiconductor and OLED screen production industries.<br/><br/>Current manipulation technologies in the semiconductor and OLED screen production sectors face challenges in handling flexible films and curved plates. Unlike conventional mechanical grippers, BESCs provide uniform force distribution across curved surfaces, making them ideal for managing various targets. The beams in BESCs offer flexibility, enabling compliance with diverse surface geometries. However, performance and stability issues arise from misalignments between the beam tip and the target, especially during repeated operations. This study addresses these issues by incorporating torsion springs to introduce tip rotatability, and by analyzing the impact of rotatability on attractive force.<br/><br/>An analytical solution was derived by examining the force-moment equilibrium of the BESC-target system under quasi-static conditions. The system was divided into three components: the beam, the spring, and the target. The analysis concentrated on the critical timepoints of full-contact breakage and detachment, yielding formulas that relate target angle, tip rotatability, and maximum attractive force. The findings indicate a positive correlation between tip rotatability and maximum attractive force, regardless of target inclination. The analysis confirmed that the highest achievable attractive force corresponds to the full-contact electrostatic force and diminishes as tip rotatability decreases.<br/><br/>Experimental verification involved three BESC devices, two with spring constants of 0.009 N*mm/deg and 0.03 N*mm/deg respectively, and one without rotatability. The results showed a 102.7% increase in maximum attractive force for the BESC with a 0.009 N*mm/deg spring constant, and a 50.1% increase for the BESC with a 0.03 N*mm/deg spring constant, compared to the non-rotatable BESC on a flat surface. Similar enhancements were observed on inclined surfaces, corroborating the analytical predictions.<br/><br/>In conclusion, this study clarifies the beneficial effect of tip rotatability on the maximum attractive force in BESCs. The presented analytical approach, validated by experimental results, provides a foundation for designing advanced BESC arrays capable of high-precision, large-area object manipulation. These findings contribute significantly to the development of robotic systems with enhanced manipulation capabilities, applicable in various technological domains including biomedicine, bionics, and minimally invasive medicine.