Applied Mechanics and Materials Vols. 687-691

Abstract: Taking the DSC as the control core and the IPM as the driver,this paper design a highly practical brushless DC motor control system with CAN bus . The system use CANopen as the application layer communication protocol, which can simultaneously control the plurality of brushless DC motor efficiently.

Abstract: Large fluctuation of wind not only make bigger change in turbine output, which may cause talkaround of wind turbine and threaten the safety of the grid. The article studied the wind disturbance problem of DFIG by simulation.The transducer used in article all have vector control and propeller pitch control. The article has some reference function to the related study.

Abstract: According to the automation and related professional laboratory present situation, combining with the main courses of teaching content, an automation integrated innovation experimental teaching platform is designed based on the current situation of the laboratory for automation specialty and related majors. This platform integrates advanced theory and technology of sensor, measurement computer control,information engineering and communication engineering, which can complete the basic experiment of main courses, but also develop some comprehensive, professional design and innovative experiments. So the platform can maximize the effect of teaching, experiment and research.

Abstract: This paper represents an auxiliary scheme for traditional deep-sea ground buoy lowering through past several years work on buoy lowering research. From this scheme the ground buoy could lay on appropriate posture to keep steady bottoming. The composition, advantage and existing difficulties of the auxiliary lowering system are also pointed in detail.

Abstract: In order to study the effects of operating parameters and surface topography on friction factors between the end faces for mechanical seals, a friction factor fractal model between end faces for contact mechanical seals was established based on the contact fractal model and the average film thickness fractal model, adopting fractal parameters to represent surface topography, separating friction into viscous shear friction of liquid film and contact friction of asperities, and representing the effect of actual rough surface on viscous shear stress of liquid film by introducing the contact factor. The influencing factors of friction factor for B104a-70 mechanical seal were analyzed by simulating. Results showed that the friction factor between the surfaces increases with the increases of spring pressure when the end faces are coarser, while the friction factor decreases slightly with the increases of spring pressure when the end faces are smoother. The friction factor between the faces decreases with the increases of the sealed fluid pressure, which increases approximate linearly with the increases of rotating speed, and it increases with the increases of fractal dimension of end faces and the decreases of the characteristic scale factor.

Abstract: Methane explosion pressure characteristics under the condition of different temperatures (25°C-200 °C) were studied by the special environment 20L explosion characteristics test system. By the experimental results, in the case of other conditions unchanged, with the increase of environmental temperature, the maximum explosion pressure of the optimum explosion concentration decrease, the maximum explosion pressure and the reciprocal of environmental temperature show linear attenuation law, the maximum pressure rise rate is not influenced by environmental temperature basically; Outside the scope of explosion limits at normal temperature and pressure, with the increase of environmental temperature, no explosion methane-air mixture are explosive gradually, the maximum explosion pressure and maximum pressure rise rate are in the relationship of different exponential growth with the increase of ambient temperature. The conclusions provide an important theoretical basis for prevent mine gas explosion accidents and coal bed methane safely use.

Abstract: To investigate the actual thermal condition in Chinese textile workshop, thermal comfort vote (TCV), actual mean vote (AMV) and thermal acceptability (TA) were carried out in this paper. 41 workers with years of work experience and 23 students with rarely entering into workshop were chosen as the subjects. Though 61% workers and 74% students feel warm or hot in the textile workshop, 24 % workers and 39% students feel very uncomfortable warm or extremely comfortable in the textile workshop, while 100% workers and 96% students were not very resistant to the thermal environment of the textile workshop. Ideally the AMV value should equal to TCV value, in fact only half of the subjects to meet this rule. On average, the TCV value is lower than the AMV value up to 0.6 scale point. Compared to students with rarely entering into the workshop, workers can adapt more easily to the hot and humid environment of the textile workshop.

Abstract: This paper studies the implementation of an ADRC to deal with depth variations of AUV. The depth model of AUV is decoupled from the 6 DOF dynamics function at first. Then, the least square method is introduced to identify the nonlinear open-loop model of AUV offline, and a more accurate depth model that varies with the elevator angle is achieved. Finally, ADRC is applied to the improved depth model with the disturbance of inaccuracy elevator angle and the error of depth measurement. The result confirms that AUV depth model varies with the elevator angle, while the ADRC controller could reject the errors in the depth sensor and the disturbances of mechanical transmission of rudder and the nonlinear variations at different operating points. Comparing to the traditional PID controller, ADRC performs better respectively with these uncertainty. The contribution of the proposed controller would support to the future application to 3D motion control and path tracking of AUV in practice.

Abstract: In the traditional design,the impact tools of broach maybe unable to achieve the requirements for the processing precision,or even occur the situation of partial fracture due to a exaggerated partial deformation.In this article,by using Pro/E we complete the 3D solid modeling and the dimensional parameterization of the impact tools for rectangle spline broach,then import the 3D model into ANSYS,to analyze and solve the whole process of load and deformation at work.It can effectively improve the machining accuracy and the reliability of broach, shorten the design cycle and reduce cost.

Abstract: In the rolling process, the upper and lower working rolls of the mill usually under different load. In order to keep good product quality, load balance control is necessary. This paper proposes a control method which uses the torque difference between upper and lower roll to compensate the given current of the upper roll motor. Simulation results show that the proposed control method can give good control effect and keep load balance.