Abstract: In this study, an accurate mechanicalhydraulic cosimulation model is established to conduct a thorough investigation on the mechanicalhydraulic coupling characteristics of a concrete wet spraying machine during boom luffing. First, the kinematic and dynamic models of the boom pitching process are established based on the composition of the boom luffing mechanism and the hydraulic transmission principle of the concrete wet spraying machine boom. Furthermore, threedimensional mechanical structure and hydraulic system simulation analysis models are established using NX and AMESim, respectively. Second, the NX′s motion analysis module, Simcenter 3D, is used to establish the mechanicalhydraulic coupling interface. Subsequently, the mechanicalhydraulic coupling simulation model of the boom luffing system is established to simulate and analyze the changes in system pressure, flow, luffing angle, and other working performance parameters when the boom is tilted up. The kinematics and dynamics simulation analysis results are further calculated using MATLAB. Finally, the results based on the NX and AMESim cosimulation, the numerical simulation results based on MATLAB, and the boom luffing test data are compared and analyzed. The results reveal the following: (1) Traditional mathematical modeling method cannot reflect the dynamic response characteristics of the system when the boom starts and brakes. (2) Mechanicalhydraulic cosimulation model can more accurately simulate the luffing action process of the boom of the wet spraying machine, and can comprehensively observe the working characteristics of the internal state variables of the luffing system. (3) Pressure test and simulation data of the luffing cylinder rodless chamber concur with each other, thus validating the accuracy of the model.

Key words: concrete wet spraying machine, luffing system, mechanicalhydraulic coupling, cosimulation, dynamics