Advanced Materials Research Vols. 328-330

Abstract: Stiction is a common problem in spring-diaphragm type valves, which are widely used in the process industry. A non-invasive method for detecting and quantifying stiction in control valve has been presented in this paper. Although there have been many attempts to understand and detect stiction in control valves, none of the current methods can simultaneously detect and quantify stiction. The method first detects nonlinearity in a control loop by the use of the sensitivity of the normalized bispectrum or bicoherence to the nonlinear interactions that may be present in the control error signal.If nonlinearity is detected, then controlled variable(pv) and controller output(op) signals are filtered using frequency domain wiener filter to obtain filtered pv and op signals.This work describes a model free method that can detect and quantify stiction that may be present in control valves using routine operating data obtained from the process. No additional excitation or experimentation of the plant is required.

Abstract: Based on kinematics analysis, this paper introduces polynomials interpolation for path planning of a 6DOF humanoid manipulator based on kinematic models. The cubic and quintic polynomials interpolations are used for interpolation algorithm. The simulation experiments show the correctness and feasibility of the algorithm and the quintic polynomial is superior to the cubic polynomial.

Abstract: The gear box is widely used in rotating machinery equipments, also it is a key component of the machinery equipment. Gear box, once it is failure, will cause serious machinery equipments failure, so the condition monitoring and fault diagnosis research of the gear box is very necessary. Its state of running and fault diagnosis can be acquired through measuring and analysis the noise of gear box. A feasible on-line LabView-based system of noise measurement on the gear box is designed by Using NI's hardware and other ordinary sound-tested equipments in teaching laboratory, as well as its applied effect is confirmed in practical test. This system realizes the signal acquisition and analysis in the online and offline conditions. It has the following functions: multiple data collection and preservation, historical data query, gearbox online monitoring and vibration quantity value alarming, etc. So, the noise detection system has very good application prospects in the actual noise detection and analysis of the gear box.

Abstract: Aiming to solve the energy saving problem in modern electric vehicle, we propose a motor-generator integration control system based on the induction motor and the fuzzy control theory in this paper. A motor-generator hardware platform is built up using the four quadrant characteristic of AC induction motor. The AC induction motor works both as driving motor of the electric vehicle and as well as the energy recovery generator. Specifically, the fuzzy direct torque control strategy is adopted in the motor state, and fuzzy instantaneous torque control strategy in power generation state. A simulation is carried out to analyze the practicality of the proposed control method, the simulation results show that the fuzzy torque control technology is well performed. Finally, a simulative energy recovery experimental platform is built up to test the proposed integration control system, and results shown that the efficiency of energy recovery could be up to 97.3%.

Abstract: Integration of the distributed business process is a hard task within the enterprise. It has a very high cost for the integration between enterprises. There is still a lot of work to do in order to simplify coordination of business process within or between the corporations in essence. XML has broad prospects in e-commerce application, promoting the development of distributed business processes to some extent. In many XML-related technologies, XML-based Simple Object Access Protocol (SOAP) and WEB services technology is particularly prominent. Using XML and related standards and technologies, combined with e-commerce security and other available technologies, the paper established WEB services for SOAP as the media. It proposed economical, compatible, extensible and safe e-commerce data integration scheme, so as to deal with the problems in E-commerce data integration for enterprises.

Abstract: Along with the development of microelectronic process, it is possible to integrate a big system in one chip. A new way to implement system on a chip is provided by the advent of FPGA. Based on Verilog HDL and the Actel Fusion AFS600 FPGA chip, the speed closed-loop control system of DC motor was designed by using options of combining the top-down thinking and the bottom-up method. PID control algorithm, encoder signal processing and PWM waveform generation etc were realized by the system. The results show that the system structure is simplified and the stability and reliability are improved. A solution of system on a chip is realized to some extent. It has extensive application value in engineering practice.

Abstract: This work presents a test model of a vibration isolation system with magneto-rheological (MR) damper, and the Bingham model to describe the dynamic process of mechanical response for the MR damper. The analytical solution of the system in passive control is obtained via the averaging method, and verified numerically. The parameters which affect the performance of the vibration isolation are adjusted appropriately; the effects of the parameter are quantitatively or qualitatively analyzed.The proposed model utilizes a method that can be employed in a variety of dynamic systems. Moreover, the model parameters have direct physical significance to the MRF damper properties.

Abstract: A feedforward-feedback controller (FFC), which is constructed by a feedforward controller and conventional PID in the global control scheme, is presented to control Inverted Pendulum in this paper. The angle of the swing-bar is defined as controlled variable for the controlled system and the displacement of swing-bar is taken as the disturbance. The feedback controller is used to control the angle and the feedforward controller is used to compensate for the displacement. Experiment results show that the proposed controller is of better control performance than the PID control scheme with two loops and the neural network control (NNC) scheme designed by Googol Technology (HK) Ltd.

Abstract: Aim at the non-linear flexible deformation characteristics of parachute, finite element analytical approach is integrated to realize the complicated time varying motion mathematical model of the parachute and implement simulation. Firstly, particle system is utilized to construct the three-dimensional geometrical model of the parachute. Then, on the basis of considering the internal force & internal air flow movement of canopy, the dynamics model during inflation process is built in the form of mass particles. Finally, through simulation calculation, the results are basically consistent with the wind tunnel test including parachute shape movement change, projection diameter change and dynamic load change rules, which the model is deemed effective and correct. The method is suitable for being applied in the engineering design of the parachute.

Abstract: In this paper, the wheeled vehicle is regard as a multi-rigid-body system and simulation model of the vehicle is established firstly by using dynamics simulation software of mechanical system ADAMS which is used most widely in the world. Secondly, through setting the initial condition and inputting various parameters, simulation analysis of skid-steer during the unilateral braking process and swerving braking process that the vehicle runs roundly in constant speed of 10km/h and 20km/h respectively is performed. In addition, vehicle velocity curves are recorded, vehicle yaw angular velocity curve are showed, Side accelerated speed curve is seen, the turning track curve of centre is drawn and the results are contrasted. Finally, some conclusions are reached that the vehicle minimum turning track radius decrease immensely than the radius which does not adopt unilateral braking and vehicle velocity could be controlled in a small velocity rage when vehicle is steering braking.