Key Engineering Materials Vols. 392-394

Abstract: According to BVXK20A NC machine servo system, a fuzzy controller is designed to achieve a faster response speed and better stability objectives. This controller is capable of automatically adjusting the three parameters of PID controller according to the tracking error E and the change in error EC. Simulation results shown the proposed control method could effectively achieve the goals of reducing the static error and improving response speed in the conditions of work condition altered.

Abstract: As a new for heavy-railway vehicle connecting device, drawbar can eliminate connective gap and improve dynamic performance of the train obviously as it is well interchangeable, simple structure, easy manufacture, convenient maintenance, mature technology, high reliability, and widely applied abroad. Through the research on reverse engineering of foreign drawbar, authors present data collecting method based on the coordinates measuring machine (CMM) and data preprocessing by Imageware software, which including noise points removal, data alignment, simplification, sorting and benchmark transformation. Converting points cloud data by Pro/E independent geometric module, 3D models based on features and constraints were reconstructed, which support the redesign of parts and their manufacturing analysis. The outcome of the paper provides effective ways in terms of drawbar techniques digesting and absorption, and also supports innovative design of new products.

Abstract: This paper introduces an automatic measurement technology of electro-hydraulic servo valve nozzle volume. Since there are several disadvantages of manual measurement in workplace, develops a new kind of intelligent volume test platform which can adjust pressure and record data automatically under constant oil temperature and match through computer. The outcome of the nozzle match experiment in the end satisfies the operating requirements.

Abstract: Web service composition is a complex and error-prone process. To guarantee its correctness, CCS is exploited as a formal tool to model Web service composition. Composition algebra is defined to specify the rules through which a compositive service can be generated. The transformation mechanisms from service compositions into CCS formalisms according to their corresponding composition operators are gone into details. Then, the automatic reasoner CWB is used to validate the constructed model, by which the dynamic behaviors of the model can be verified and such composition errors as deadlocks can be detected in advance, thus enhancing the composition reliability and avoiding runtime failure. Finally, an example is given to illustrate the effectiveness of this approach.

Abstract: In order to implement basic motion functions of lunar rover over uneven terrain, wheel kinematics of a novel lunar rover with each wheel independently driven was studied. In terms of mechanism principle and configuration features of the rover the kinematics model of wheels was set up by utilizing modified D-H method. The simulation analyses of wheels traversing over uneven terrain were carried out by using MATLAB software. The velocity simulation curves of wheels’ centers relative to rover body were acquired. The research results give motion parameters of wheels varying with rough terrain, and from the velocity simulation curves we can gain velocity control instructions of rover wheels over uneven terrain. It illustrates varying of lunar rover wheels’ velocity with uneven terrain. The paper provides a theoretical basis for accomplishing motion control and autonomously avoiding obstacles of lunar rover and so on.

Abstract: Based on the theory of Wavelet decomposing algorithm, in this paper an algorithm of redundancy real-time denoising is presented, and the test of on-line identification mode of a hydraulic cylinder’s work load pressure signals was fulfilled. This method can improve the stability of the signal collection and the control accuracy of hydraulic cylinder pressure effectively, solve the crawling phenomenon of hydraulic cylinder when working, and reduce the signal collection error resulted from the load mutation. By means of controlling the wavelet decomposing depth, the calculation amount of real-time denoising is controled, thus the optimization of the signal, damping vibration and denoising are achieved.

Abstract: In order to resolve the problem of being unable to test the ring welding line of middling and small modulus gear by handwork ultrasonic testing due to small size, the automatic ultrasonic testing technology is studied and the automatic ultrasonic testing system has be studied. Normal beam testing adopts the radial incident detection methods from the inside hole surface using a higher frequency focus probe and the better testing result is obtained. The automatic ultrasonic testing system is made up of ultrasonic testing subsystem, mechanism scan subsystem, control subsystem, ultrasonic testing signal processing and display subsystem, and system calibration test pieces .The result of testing can be displayed on the computer screen or printed in the form of curve and statistical data.

Abstract: The sawtooth chip from hard cutting can influence on the precision of the form and dimension, the machined surface integrity and the tool life. A study on the microcosmic dynamic fracture mechanism of hardened bearing steel carried out by the author, based on the microcosmic observing and analysing of sections of the chips from PCBN tools cutting GCr15 bearing steel. The experiments and analyses indicate that the adiabatic shear loses stabilization in the primary deformation zones due to thermal softening during cutting machining, and shear ductile fracture limitation of the chip forms. The sawtooth chip formation of GCr15 bearing steel hardened cutting results not from the periodical brittleness fracture but from periodical adiabatic shear fracture; being no clear damnification before the adiabatic shear loses stabilization, thermal softening occurs and be controlled by nucleation, growth and coalescence of microvoids in the whole shear fracture tenacity progress.

Abstract: The proposed Axis-based Look-ahead NURBS Interpolator (ALANI) strictly confines the component acceleration and jerk at each axis during every interpolating period based on the mechanics of the machine tools, so that the acceleration and jerk at axes can not exceed the limit in order to avoid immoderate vibrations and shocks. Contour precision is also strictly guaranteed while interpolating. The interpolator can trace back and recalculate previous data if necessary after forwards calculation and verification. And the recalculation algorithm is able to choose optimized machining parameters to attain high efficiency. The introduction of ALANI and simulation experiment is present in this paper.

Abstract: Hybrid machine tool is studied in this paper and its interpolating algorithm strategy is analyzed including line and arc rough and fine interpolation method. Cubic B spline is used as fine interpolating algorithm and error evaluation of arc interpolating algorithm is presented. This algorithm model is sample and can be used in many situations.