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The domestic 25-ton truck crane has the problems of high system pressure during steady slewing and great hydraulic impact when slewing motion starts and brakes. So the simulation model of the slewing hydraulic system and the core hydraulic components was constructed by AMESim. The flow areas of throttling grooves on the valve rod of the directional control valve were calculated by Matlab and converted into text files, which were imported into the simulation model. To get the load parameters of slewing system in different work conditions, an experiment on real truck crane was performed. Then the problem work conditions recurred in the simulation, which showed the veracity of the simulation model. Based on the simulation model an improving method was presented and simulated and the simulation results showed that through the improving method, the system pressure and the hydraulic impact could be efficiently reduced.

A giant magnetostrictive actuator presents advantages such as large strain, high precision, and quick response. It is a hotly debated research topic in the field of micro drivers; however, the nonlinear intrinsic relationship between its output and input signals make it difficult to construct its nonlinear eigen model in the process of its practical application. Therefore, the motivation of this paper is to study the nonlinear magnetic–mechanical coupling characteristics of the giant magnetostrictive actuator, which is driven by free energy hysteresis characteristics. The nonlinear magnetic–mechanical coupling model under the weak form solution is deduced from the basic electromagnetic and mechanical theories, based on the distribution law of the axial magnetic field simulation, carried out to analyze the output displacement characteristics of the giant magnetostrictive actuator under preload. Experimental characterization of the device is also studied in the built experiment setup. Research results show that the experimental results coincide well with the simulation results, which show that the designed magnetic circuit for the giant magnetostrictive actuator is correct, and the coupling model of magnetic and machine of the giant magnetostrictive actuator based on the free energy hysteresis characteristics is reasonable.

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