Advanced Materials Research Vols. 328-330

Abstract: This article briefly describes the basic theory of independent component analysis (ICA) and algorithms. Independent component analysis (ICA) method is employed to separate the mixed vibration signal, measured from linear sensor array. By calculating the spatial spectrum function, identification and tracking of multiple moving targets achieved. The results show that, ICA can successfully detect and track multiple targets.

Abstract: In order to realize precise contact tasks with an unknown environment, robotic force controllers have to adapt themselves to the unknown environment. In this paper, an effective controller for robot contact tasks is proposed using sliding mode switching surface as a sole fuzzy input variable for substituting the feedback controller in the model reference adaptive control (MRAC), the fuzzy force controller determines the adjustment to the position control loop, adjust the fuzzy controller parameters according to the difference between the actual and desired force responses. There is a sole fuzzy input variable in fuzzy logical controller(FLC), the total number of rules is greatly reduced compared to conventional FLC, hence generations and tuning of controller are more simple and easy. Simulations prove that the excellent adaptability as well as high precision is obtained by the proposed strategy.

Abstract: A high-precise automatic positioning system for data sample of linear time grating sensor is designed. In order to achieve linear time grating sensor of data sample, improve measure work efficiency, an ARM MCU is used as a major chip to control the stepper motor to rotate. In this way, the stepper motor drives the ball screw, the moving probe of linear time grating sensor and reading head of linear grating to move synchronously. A high-precision automatic positioning of the system hardware is designed. In addition, ARM controlling circuits and stepper motor driving circuits are designed. Therefore, the special communication interface is designed for the high-precision automatic positioning system, receiving the feedback signal from time grating sensor, forming a high-precision closed loop control system, and communicating with upper computer by serial. Experiment results prove that the positioning precision of control system can reach 0.1 um.

Abstract: During the roll forming factory, the front bearing of AC motor was always malfunction. The problem was that there was large axial vibration and the deterioration was in the trend of rapid development. In order to make early preparations for repairs and maintenance to determine the basis for decision-making, the motor bearings were under monitoring when running. In AC drive systems, bearings are more likely to be damaged from the highly accelerated/decelerated operation and the effects of electrical discharge machining resulting from high dv/dt, which are introduced by PWM input voltage. Multi-level inverters offer better sinusoidal voltage waveform than 2-level inverters due the fact that output voltage can be formed using more than two voltage level. This causes the THD to be lower. Switching losses are reduced because switching frequency can be lower than in 2-level inverter. According the testing data analysis, bearing had been replaced with 3-level AC inverter and maintenance of the response had been decided.

Abstract: The traditional passive vibration isolation system can reduce the vibration transmission greatly while the excitation frequency is times higher than its natural frequency. As the external excitation approach its natural frequency, vibration isolator system is invalid. In this paper, a new variable stiffness vibration isolator was designed to solve the low-frequency resonance problem of the traditional isolator by combining toothed electromagnetic spring with passive isolator. Theoretical analysis and experimental results illustrate that this isolator met the design requirements and obtained the no resonance operating characteristic at the low frequency.

Abstract: AC algorithm of blind sources has been applied to the identification of engine noise sources. However, the testing platform based on the blind separation theory is difficult to actualize some experiments and obtain data in the real environment, or to obtain these requires high cost. Therefore, this paper proposes a new approach to construct an experimental testing platform-Sinmulink Model so as to identify engine surface noise sources. This model is applied to the test of the experimental data. These experiments demonstrate that Simulink model is efficient to identify engine noise source and the testing data accord with that made by the former platform. It is obvious that Simulink model, to some degree, can be used to replace engine surface noise sources testing platform.

Abstract: Surface tracking with robot force control for position-controlled robotic manipulator is proposed. A neural network is applied to classify the unknown environment based on its dynamic response of the environment, on-line force feedback data are employed to estimate the normal and tangential directions of the unknown environment, the estimated vectors are used to generate the reference trajectory for the target impedance model. Real-time calculates the curvature of curve to be tracked to adjust the speed of the tangential direction, the reference scaling factor is determined by fuzzy reasoning according to current and forecast contact force, in order to adapt the reference trajectory generated for the changeable environmental parameters and control parameters. Simulation is conducted to verify its force tracking capability.

Abstract: According to request of the control system in the wine fermentation process at a winery, the design plan of the control system based on Siemens PLC and King View is put forward. Lower processor was composed by series CPU module and ET200S module of Siemens S7-400 PLC in that control system; moreover, centralized management and real-time monitoring of collected data are carried out through the upper processor that adopts industrial computer and the software of King View. The practice shows that the control precision and the reliability of the control system of the wine fermentation process both have met the needs of the control.

Abstract: In ocean exploitation, long hydraulic pipelines are usually applied. Using SimHydraulic software, the model of hydraulic system including hydraulic fluid, pump, hydraulic cylinder, directional control valve, relief valve, accumulator, long supply pipeline and return pipeline, is established. The position of the cylinder piston is measured by position sensor, while the supply pressure of the cylinder and the system supply pressure are measured by pressure sensors, the directional control valve is controlled by an on-off signal. The simulation was carried out, the impact of long hydraulic pipeline on system performance is also analyzed.

Abstract: Objective: The aim of this paper is to study the system problem to help pilots get the information which is useful among large amounts of data; Method: A new experiment on the limit of data strobe signal was built; Result: On the basis of theoretical consideration and analysis of experimental results, the effect on pilots' cognition and the design of display/control system was initially explained; Conclusion: The results showed that the increase of limit of data strobe signal can be accepted by objects; limit of data strobe signal will increase quickly by using digital or simple characters instead of words, but this will slightly increase performance errors; interruption of information doesn’t affect too much on limit of data strobe signal.