Development and Control of a Flying Ejector-Pin System With Local Gain-Scheduling ILC Scheme

The MiniLED mass transfer process requires high-speed and high-precision devices to guarantee mass production and precise mounting. The motivation of this article is to combine the ability to enable the mechanical transfer approaches to run in the manner of continuous manipulation to increase efficiency. The developed system achieves this objective by proposing a compliant flying ejector-pin transfer (CFET) strategy, whose performance is enhanced by a novel local gain-scheduling iterative learning control (LGS-ILC) scheme. First, a CFET strategy is proposed, which is achieved by incorporating synchronous motion into the flip-chip-on-board transfer method. Then, the development of a flying ejector-pin system is presented, including system design and its working principle. Next, to provide high-speed and high-accuracy tracking controls for CFET implementation, a first-step vibration (FSV) behavior is analytically identified and modeled to capture the dynamic characteristics of the system in the case of high-speed trajectory tracking by ILC-based motion control. Thereafter, to address this behavior, a novel LGS-ILC is designed, which improves the tracking performance by predicting and suppressing FSV. Besides, the convergence of LGS-ILC and control system are analyzed in theory. Finally, a series of verification tests were carried out, including experimental validation of LGS-ILC and closed-loop CFET experiments. The results indicate that the LGS-ILC can effectively improve the performance in high-speed trajectory tracking. Besides, the transfer period and accuracy of the developed system are achieved as 50 ms and \pm 2.5 \mum, respectively, uniformly proving that high-efficiency continuous manipulation is achieved.