Orifice-restricted hydrostatic thrust bearings are broadly employed in ultra-precision machine tools, aerospace industries, and so forth. The orifice length–diameter ratio (OLDR) is one of the significant geometrical parameters of the orifice-restricted hydrostatic thrust bearing, which directly affects the performance of the bearing. To accurately guide the design of the hydrostatic thrust bearing, the effect of the OLDR on the performance of the hydrostatic thrust bearing needs to be thoroughly and scientifically investigated, especially for ultra-precision machine tools. In this paper, the influences of various OLDRs are comprehensively studied using the computational fluid dynamics (CFD) approach on the pressure pattern, velocity, turbulent intensity, and vortices, as well as the load capacity, stiffness, volume flow rate, and orifice flow resistance of the hydrostatic thrust bearing under identical operating conditions. The obtained results show that there are differences in performance behaviors of the hydrostatic thrust bearing caused by different OLDRs. Some new findings are obtained, particularly in the second-order small vortices which appear in the annular recesses with all OLDRs except that of 2, and the flow resistance does not always increase with increasing OLDRs. Finally, the proposed CFD approach is experimentally validated.

Micro-hole aerostatic bearings have emerged as critical components in ultra-precision machining systems, offering a superior load capacity, stiffness, and stability compared to traditional orifice-based designs. These enhancements are primarily attributed to the high-density configurations of micro-holes and the reduction in hole diameter. However, research on the design and analysis of micro-hole aerostatic bearings for high-rotational-speed applications remains limited. In this study, the finite element method (FEM) was employed to solve the Reynolds equation, thereby conducting a systematic evaluation of the static and high-speed performance characteristics of micro-hole aerostatic thrust bearings. The effects of restrictor types, micro-hole layouts, structural parameters, and centrifugal deformation under high-rotational-speed conditions on bearing performance have been comprehensively examined. The objective of this study is to provide a basis for the design of micro-hole high-speed aerostatic spindles.

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

A delay generator is a timing control device that can generate a delay for the input signal according to the actual requirements. A delay generator with a combination of rough delay and precise delay is implemented on a Xilinx Kintex-7 series FPGA with a design scheme based on carry delay chain. The delay generator uses the delay time parameters sent by the upper monitor to work and to reflect the current working state to the upper monitor. In this article, a theoretical model of the delay generator is designed, and a delay compensation scheme is proposed to make the working state of the theoretical model closer to the actual circuit. Through simulation experiments, the time resolution of the delay generator is 54 ps, and the time accuracy is less than 50 ps. The delay scheme adopted in this article is highly scalable, and the time resolution and time accuracy can be further improved. Finally, a theoretical model of the delay generator with relatively high time resolution is implemented through low resource occupancy rate and little workload.

Aiming at the problem that the output of motor driver driving linear motor is not stable enough and will be accompanied by large power ripple, which makes the motor speed unstable and has a great impact on the accuracy, a linear driver is designed. The AB power amplifier circuit is mainly used by the linear driver to achieve linear output of current, and the negative current feedback is used to stabilize the output current. For the software part, a program based on ARM is designed to parse the commands of the upper computer and control the hardware circuit according to the commands, so as to achieve specific functions. The test results show that the non-linear error of the power amplifier driver is only 3.6%, and the three-phase sinusoidal current with different frequencies and amplitudes can be output as needed.

Medical hydrogels represent a promising solution for the treatment of corneal diseases and trauma, offering potential to address the shortage of donor corneas. To meet the functional requirements of artificial corneas in tissue engineering, it is crucial to fabricate biomimetic structures with high optical transparency using 3D printing techniques. As fiber alignment during the printing process has a pronounced impact on light transmittance, precise control of the printing parameters is essential. This study focuses on the experimental optimization of 3D printing conditions for hydrogel materials to improve their physical properties, particularly optical clarity, thereby enhancing their suitability for artificial corneal applications. Collagen derived from bovine Achilles tendons was chosen due to its excellent printability. A series of controlled experiments were conducted to systematically investigate the influence of key process parameters on hydrogel transparency. The findings enabled the identification of an optimized parameter set that significantly improved the optical properties of the 3D-printed biomimetic corneal stroma. Additionally, cell seeding and culture assays confirmed the favorable biocompatibility of the developed material.