Applied Mechanics and Materials Vols. 687-691

Abstract: Aimed at rejecting the disturbance for Ship-borne Servo Control System, using the ADRC method to improve the disturbance rejection ability of system. And the model is validated by PID, the simulation results show that the anti-interference ability could be improved by of ADRC method, and the controller has engineering function and prospect.

Abstract: Electro-hydraulic servo system has more disturbance and noise factors at low speed than in other situations of the whole operating process, so the stability and performances of the system would be greatly affected by these factors. It is generally accepted that nonlinear torque disturbance is the main interference factor. In order to compensate above disadvantages, a sliding mode variable structure control was proposed to adjust the electro-hydraulic servo system. The results indicate that the provided approach possesses satisfactory performances in stability, robustness, steady state error and so on.

Abstract: Based on structure analysis of a certain ship-borne servo control system, the target velocity is contributed to exterior unknown disturbance and the system parameter change is looked as interior unknown disturbance. The extend state observer is used to estimate the disturbance accurately with the input and output information of system response, then the controller can compensate the disturbance furthest. The simulation results show that the ADRC method has good robust performance, compared with the traditional PID controller. Without using the sensor to measure the target state, it can satisfy the system requirements with a simple structure, it shows the controller has good aspect to have good engineering function and prospect.

Abstract: The welded joint is the critical area in the structure integrity investigation. To understand the influence of the mechanical heterogeneous on the fracture parameters in welded joint, the represented way of the welded mechanical heterogeneity and its effect on the mechanical parameters at the crack tip are analyzed by using an elastic-plastic finite element analysis software in this paper. The investigated results indicate that continuous change of material mechanical properties could express the effect of the actual welded mechanical heterogeneity on the fracture mechanical parameters change in the welded joint more accurately, which provide a new approach on the fracture problem investigation in welded joints.

Abstract: This paper selects two typical micro-displacement control platforms,and conducts comparative analysis of strength of their flexible guiding mechanism.Stress expressions of flexible guiding mechanism are respectively derived to obtain the relationship between the maximum stress and geometric parameters and the relationship between tensile stress and bending stress.with moving the same displacement,the difference of stress of the two micro-displacement control platforms is small,and can be ignored.

Abstract: In this paper, the pressure vessel of a project is mentioned, the key technique of multilayer-wrapped type cylinder system and inspection technology are discussed. This paper analyzed the main manufacturing difficulties, which can provide reference for similar products.

Abstract: In order to prevent damage caused by instantaneous power failure to high-speed equipment, the thermoelectric energy conversion system for controller of magnetic bearing is studied. The heat source is used by the power loss of supply modules and the cold source is used by heat conduction aluminum block. The semiconductor thermoelectric generator produces direct-current working voltage between heat source and cold source. The overall design method of the energy conversion system is presented. The theory and design of circuits to thermoelectric energy generator, voltage regulator and charging for lithium polymer battery are analyzed. The experiment results show that this thermoelectric energy generator system is feasible and effective. The circuit can be adapted to change in output power due to temperature difference at both ends of the thermoelectric module. It achieves energy storage of the recovery from thermoelectric generator.

Abstract: When rotor exist eccentricity, there will be mutual effect between bending vibratory and torsion vibration. This kind of mutual effect will generate bending-torsion coupling vibration. At present, the majority research on the bending-torsion coupling vibration are focus on the nonlinear characteristics, but seldom on the coupling resonance amplitude of the bending-torsion coupling vibration. Given this situation, this article starts with resonance amplitude have further research on the bending-torsion coupling vibration. Firstly, a model of eccentric rotor with coupled bending and torsion vibrations was built and the vibration equation was solved by small parameter method. Then considering the forcing frequency and dynamic tress of the existing equipment can provide,the main resonance of bending-torsion coupling vibration stress relief was determined, and the mechanism of bending-torsion coupling vibration stress relief was put forward. Finally, the example demonstrated the theoretical analysis. The research provide thought and basis for the bending-torsion coupling vibration.

Abstract: Designed a new type of wind turbine internal maintenance lifting platform using three-dimensional drawing software SolidWorks to establish the 3D model for the internal maintenance lifting platform. Imported platform bridge part to ANSYS Workbench static and modal analysis module; make load analysis according to the wind turbine operating environment and platform’s most dangerous operating condition and obtain the maximum stress of platform bridge structure and place and form of deformation. Obtained multiple order natural frequency and vibration mode of platform bridge structure through modal analysis. Compared with the standard, it shows that this structure satisfies the strength and stiffness requirement and will generate frequency affecting human body higher than the nature frequency. This thesis provides a theoretical foundation for designing the wind driven generator internal lifting platform and provides a reference for optimization design.

Abstract: A buoyancy control system was presented to realize the powerless descent/ascent motion for an under-actuated AUV like REMUS. The sea water was injected into or drained out of the pressure water tanks to tunes the residual buoyancy of the vehicle, and the buoyancy control was realized. An engineering hovering control law based on buoyancy control approach was proposed to keep the vehicle hovering at the programmed depth. The injection and drainage instructs were worked out only based on depth data and its difference, so the hovering control system need not additional sensors. The simple and reliable hovering control system was applied to a type of huge under-actuated AUV, and the experiment results show that it is feasible.