To analyze the deflector-jet servo valve’s internal flow characteristics, a theoretical model of the complicated flow distribution in the deflector plate is established based on the offset jet attachment theory. When the deflector plate offsets, jet attachment parameters are attained to figure out the jet’s bending and colliding process. On this basis, an analytical method of acquiring the pilot valve’s pressure gain is derived. According to an actual pilot stage’s structure, pressure gain calculations are carried out. Meanwhile, the pilot valve’s mesh model is established for numerical simulation in order to examine the accuracy of the theoretical model. Calculation and numerical simulation show that the final oil jet is not sensitive to the deflector plate’s movement, which directly reveals the pressure stabilizing effect of the V-shaped structure on the deflector plate. Moreover, the experiment on the pressure gain is accomplished and experiment results verify the accuracy of the analytical calculation.

This paper studied laser induced thermal-crack propagation (LITP) dicing of a glass-silicon double-layer wafer with high scanning speed. A defocusing continuous laser was used in the experimental system as the volumetric heat source for the glass layer and the surface heat source for the silicon layer. Based on the principle of thermal-crack propagation, the commercial software ABAQUS was used on the simulated analysis, and the results of temperature field and thermal stress field distribution with high and low speed were compared. The experiment was executed in accordance with the simulation parameters. The surface morphology of the cut section was described by optical microscopy and a profilometer, and combined with the results, the non-synchronous propagation process of the crack under high speed scanning was revealed. Most importantly, the scanning section with a nanoscale surface roughness was obtained. The surface roughness of the silicon layer was 19 nm, and that of glass layer was 9 nm.

A macro–micro dual-drive motion platform is a class of key system utilized in ultra-precision instruments and equipment for realizing ultra-high-precision positioning, which relates to the fields of semiconductor manufacturing, ultra-precision testing and machining, etc. Aiming at the ultra-high-precision positioning control problem of macro–micro dual-drive systems containing mechanical backlash, this paper analyzes the combined effect of mechanical coupling and backlash, and proposes a macro–micro compound control strategy. Firstly, the system dynamic model, including mechanical coupling, is established, and a quasi-linear backlash model is also proposed. Secondly, based on the above model, a stepwise nonlinear identification method is proposed to obtain the backlash characteristic online, which is the basis of accurate backlash compensation. Then, for the macro–micro structure containing the backlash, a macro decoupling control method, combined with a micro adaptive integral sliding mode control method and backlash compensation, are designed coordinately to guarantee that the large-stroke macro–micro cooperative motion reaches micron-level accuracy. Moreover, the boundary of the positioning error is adjustable by tuning the controller parameters. Finally, both the simulation and experimental results demonstrate that the proposed identification method can estimate the time-varying backlash precisely in finite time, and the system positioning accuracy can achieve an average 20 μm with long stroke and backlash influence, which is much higher than that using the traditional method and provides theoretical guidance for high-precision positioning control of a class of dual-drive motion platform.