Advanced Materials Research Vols. 562-564

Abstract: For the five degree-of-freedom (5-DOF) AC active magnetic bearing (AMB), which is a multivariable, nonlinear and strongly coupled system, conventional single-variable controller cannot meet the control requirements. Based on the state space model of 5-DOF AC AMB and direct feedback linearization, the equations of coordinate transform and nonlinear state feedback can be simplified into differentiating output equations, which achieves the input-output linearization of 5-DOF AC AMB system. Then, the system can be decoupled into five independent 2-order linear subsystems and realizes the completely decoupling of 5-DOF. Finally, the internal model control (IMC) method is employed to synthesize the subsystems, in order to avoid the performance deteriorated due to the model error and external disturbance. The results of simulation example demonstrate that this decoupling control strategy can realize not only the dynamic decoupling of 5-DOF AC AMB, but also the good dynamic/static performance and robustness.

Abstract: All of the performances of the car, break performance is one of the most important. In the stage of automotive design, road tests usually are not available, only special brake tests are used to simulate the test. Using brake tester is a good measure to decide the vehicle braking performance. To carry out the brakes test and to explore inertia, it can better simulate the actual use of the brake mode and environmental conditions, a more realistic response to brake performance, not only brake to improve the level of R & D to enhance the braking technology, but also can improve brake testing technology to improve the design level test bench, the most critical is a good control analysis of the mathematical modeling of the brake product development, quality control, and vehicle braking performance are very important. Based on the data calculation and analysis, model, and the control algorithm, obtained reasonable control of the brake test bench mathematical modeling, and the method to do the appropriate improvements.

Abstract: 260T hot-metal car is a huge shape machinery product used in iron and steel plant for the short distance transportation. The work conditions of the hot-metal car are bad, so the reliability of the product structure must be guaranteed. During the structure design, theoretical study and computer simulation analysis of the car frame are taken using the commercial finite element software. The tests for the 260T hot-metal car product are accomplished by using the modern static testing technology to verify the theoretical calculation. The paper describes the test scheme and field test process, extracts the strain and stress value of key points on the car frame and analyses the test data. At last, the test result data are compared with the finite element computation result data, verifying the theoretical calculation.

Abstract: Pipe automatic handing system is an important part of automation rig, which replace manual operation by using mechanical equipment, and realize the reciprocate transfer operation of drill pipe. It is an effective way to make drilling safe, healthy and efficient. This paper introduces the common structure, the function and the basic principle of the pipe automatic handing system used now, and the different structure are compared.

Abstract: Roll eccentricity is widespread in the strip mill, has cyclical impact on strip thickness, so disturbance compensation is required to improve the product quality. The key step of disturbance compensation is to obtain reliable roll eccentricity signal. Existing direct measurements of roll eccentricity signal method requires special equipments with high precision but not practical enough. There are few detection methods which including rolling velocity. Roll eccentricity signal is difficult to directly measured, should fuse many kinds of detectable signal to be extracted through the data analysis which includes rolling force, roll gap, incoming thickness of rolled piece, exit thickness, tension, and so on. This paper puts the four high mill as an object, according to the influence of the main factors of roll eccentricity ——backup-roll eccentricity for analysis, develops a Roll Eccentricity Phase Identification System. This system extracts from amplitude of eccentricity signal, combines eccentricity signal’s frequency with phase through roll segmentation marker integrating rolling speed, according to its cyclical change law to achieve the signal calibration by testing amplitude characteristics to determine the phase of roll eccentricity of the current rolling area. After determining the signal phase, detect the phase of eccentricity signal according to integration of rolling speed, and through phase detection to ensure the reliability of the detectable phase. This system is verified by the experiment in four high mill, the results show that the method of phase detection of eccentricity is effective, it provides a simple and effective new way for the phase extraction of roll eccentricity signal, and can used in similar condition.

Abstract: AutoCAD software is the most popular engineering graphics software today. It is a high performance general drawing platform and used by most of the engineering and technical person. In this paper, the second development of AutoCAD was used to analyze and discuss.

Abstract: Excessive vibration was observed from nitrogen reciprocating compressor buffer tanks and pipelines since the operation of this unit started in a coal chemical plant. Welding points had been frequently cracked on bolt buffer tanks, pipelines and bolts, which often led to a delivery failure of coal for subsequent reaction, causing great economic losses. In order to identify the root cause of vibration, a comprehensive analysis on the reciprocating compressor and pipeline system was conducted. The vibration has been kept within an acceptable range after the adjustment. The total production in the factory has been increased with effectively controlled cost and energy consumption. The probability of production system shutdown and accident is also significantly reduced.

Abstract: Excessive vibration was observed from hydrogen reciprocating compressor pipelines since the capacity expansion revamping of this unit finished in a refinery. The production had been frequently stopped since the vibrations on the pipelines exceeded the alarm value, which often led to a delivery failure of Hydrogen for subsequent reactions, causing great economic losses. In order to identify the root cause of vibration, reduce the airflow pulse peak, and enhance the pipeline security strength and rigidity of the structure, a comprehensive analysis on the reciprocating compressor and pipeline system was conducted. The vibration has been constrained in an acceptable range after the adjustment，and the unit has gotten a long-period and stable operation.

Abstract: This paper presents the results of a combination of interval perturbation method and the XFEM (IXFEM) to analyze Linear Elastic Fracture Mechanics problem. Uncertain parameters were expressed as interval variables and sub-intervals perturbation for the elements employed in the analysis. The IXFEM method proved very robust in handling parameters uncertainties in fracture problems.

Abstract: In order to avoid the limitations of traditional mechanism modeling method, a neural network (NN) model of variable - pitch wind turbine is built by the NN modeling method based on field data. Then considering that from wind turbine’s startup to grid integration, the generator speed must be controlled to rise to the synchronous speed smoothly and precisely, a neural network model predictive control (NNMPC) strategy based on the small-world optimization algorithm (SWOA) is proposed. Simulation results show that the strategy can forecast the change of generator rotational speed based on the wind speed disturbance, making the controller act ahead to eliminate the impact of system delay. Furthermore, the system output can track the reference trajectory well, making sure that the system can connect the electricity grid steadily.