Since the emergence of digital hydraulic technology, it has achieved good results in intelligence, integration, energy saving, etc. After decades of development, and it has also attracted wide attention in the industry. However, for many years, the definition of digital hydraulic technology has differed between researchers, and there is no uniform definition. Such a situation affects the development of it to a certain extent. Therefore, this paper gives the exact definition of digital hydraulic technology based on a large number of researches on it. At the same time, the paper analyzes the research status and developmental process of the such a technology, and we forecast the development trend of it.

A hydraulic pipe is a basic component of the aero hydraulic system, while high pressure and high speed lead to the enhancement of multiple field coupling effects, such as the structure, fluid, heat, and sound of the aero hydraulic pipe. A larger elastic deformation of the pipe and the more common unsteady flow of fluid can aggravate the vibration and noise of the hydraulic pipe system. Based on the 14-equation model of fluid-structure-interaction (FSI) vibration of aero hydraulic pipe, a model suitable for a wide Reynolds number range is proposed by comparing and analyzing various kinds of friction coupling models. This model is used for the FSI dynamic behavior analysis of aero hydraulic pipes, which improves the accuracy of FSI frequency-domain solutions under high Reynolds number conditions. Second, based on the 14-equation model of FSI vibration of aero hydraulic pipe and the transfer matrix method, the mathematical model of airframe deformation load of an aero hydraulic pipe is established, and the evolution law of the FSI dynamic behavior of the aero hydraulic pipe under different airframe deformation loads is analyzed. All the above analysis results were verified by the experimental analysis. The error of the analysis results of the FSI vibration frequency is smaller than 5% compared with the experimental results. The results show that the proposed method is feasible and effective for predicting the hydrodynamic behavior of the aero hydraulic pipes under load conditions.

At present, the interference couple parts are assembled manually which not only has a long assembly cycle, but also has uneven assembly quality according to personal ability. Combined with the current production situation, this paper studies the measurement method of motor keyway width accurately calculates the overall dimensions of keyway and flat key & calculates the appropriate interference range. Design the flat key press fitting tooling in a narrow space to effectively solve the reliable method of press fitting interference coupling parts. The press fitting force is calculated theoretically which is supplemented by simulation analysis.the range of the actual press fitting force is obtained by using the automatic control digital press fitting technology, so as to realize the precision assembly of the interference couple. Through the research of this paper, the effectiveness of precision assembly technology of automatic control digital interference couple is verified.