Achieving high-throughput uniform scanning of stick-slip actuators is challenging because the conventional sharp triangular trajectory can easily induce dynamic friction between the compliant mechanism and the end-effector, which can lead to scanning failures. To address these issues, this article proposes a smooth trajectory that integrates a linear rising edge for uniform sampling with a cubic B-spline curve for smooth transitions. By optimizing the parameters, the trajectory effectively minimizes peak acceleration and reduces high-frequency components, thereby enhancing both scanning throughput and accuracy. The experimental results demonstrated that the proposed trajectory yielded a scanning throughput 2.86 times greater than that achieved with the conventional triangular trajectory. Moreover, the proposed trajectory demonstrated superior accuracy in scanning across all tested frequencies. This advancement is significant for expanding the applications of stick-slip actuators in high-throughput scenarios.

Multi-focal microlens arrays provide notable advantages over mono-focal counterparts, such as multi-scale imaging capabilities and optical aberration correction. However, existing multi-focal microlens arrays fabricated on continuous surfaces are incapable of achieving confocal imaging. As a result, multiple focus adjustments are required to acquire comprehensive image data, thereby complicating system design and increasing operational duration. To overcome this limitation, a stepped confocal surface microlens array is proposed, capable of simultaneously capturing images with multiple depths of field, various field-of-view scales, and different resolutions—without the need for additional focus adjustments. A combination of femtosecond laser processing and chemical etching was employed to fabricate microlenses with varying curvatures on a stepped fused silica substrate, which was subsequently used as a mold. The final stepped confocal microlens array was replicated via polydimethylsiloxane (PDMS) molding. Preliminary experimental analyses were carried out to determine the relationship between processing parameters and the resulting focal lengths. By precisely controlling these parameters, the fabricated stepped confocal microlens array successfully enabled confocal imaging, allowing for the simultaneous acquisition of diverse image data. This microlens array shows great potential in advancing lightweight, integrated, and highly stable optical systems for applications in optical sensing, spatial positioning, and machine vision.

The achievable performance of the complementary-filter-based parallel control for a compound dual-stage nano-positioning system is limited by its model-based sequential design structure. This study proposes a frequency-response-data-based optimization approach for the simultaneous and systematic design of the complementary-filter-based dual-feedback controller. The design procedure and corresponding Nyquist stability analysis are presented in detail. By directly utilizing frequency response data, the proposed method mitigates the effects of system identification errors. The controller design objective is formulated as a constrained optimization problem to achieve a flat amplitude frequency response with high control bandwidth. Comparative experiments conducted on a dual-stage nano-positioning system verify the effectiveness of the proposed approach. The proposed method reduces the root-mean-square tracking error from 70.6 nm using the baseline integral controller to 21.3 nm at 50 Hz sinusoidal tracking, demonstrating its clear superiority.