Applied Mechanics and Materials Vols. 184-185

Abstract: The paper presents a novel acceleration/deceleration (acc/dec) control algorithm based on moving-average. The proposed algorithm makes use of the moving-average method to dispose the velocities of all the discrete points obtained by linear acc/dec control algorithm. The acceleration curve is continuous and the speed curve is smooth obtained by this method. Furthermore, the proposed algorithm has easier calculation to achieve. Therefore, CNC simulation system with NC instruction interpretation is established based on this proposed algorithm. The system not only simulates the executive process of NC program files, but also realizes the simulation of speed and acceleration curve, process time and distance with the unit of controlling period. At the same time, the simulation system considers the acc/dec control of feed speed therefore the simulation time equals the real process time. Those will be the value of the instruction to the process of the real machining.

Abstract: In automated micro-hole drilling system, in order to improve the drilling performance and reduce of production costs by maximizing the use of drill life and preventing drill failures, the drill bit wear state monitoring is more important. However, drill bit wear is difficult to measure in drilling process. By observation, wear failure of the drill bit could cause related changes of the spindle current signal, so construct fuzzy control mathematical models with the relationship between drill bit wear and spindle current, genetic algorithm and fuzzy control theory are applied to micro-drilling system in this paper .The membership functions of fuzzy control model are optimized by genetic algorithms. Through calculation, we can get drill bit wear value which used as monitoring threshold value in micro-hole drilling on-line monitoring system to avoid the drill breakage and improve the monitoring reliability.

Abstract: CNC machine controlled by closed-loop gains an increasing attention because of its accuracy, however the vibration occurs easily. The methods for the optimization of the servo control to eliminate CNC machine vibration are proposed in this essay.

Abstract: This paper introduces an on-line monitoring and fault diagnosis system of Fan based on LABVIEW and Advantech PCI-1711 data acquisition card. Through the FFT spectrum analysis of domain vibration, four conditions corresponding to imbalance, misalignment, friction and oil whirl are tested. The result shows that the system can identify these common faults correctly. The system has the advantages of reliable stability, high accuracy and easy manipulation.

Abstract: To achieve cruise missile accurate trajectory tracking control, an observer-based tracking control method is designed. An observer is developed to estimate the states and control signals of desired trajectory as the inputs of the tracking controller. The linear quadratic optimal control is used to realize full-state feedback control for trajectory tracking. A certain cruise missile is used for the tracking simulation and the result shows satisfactory performance, the control method is simple and suitable for engineering applications.

Abstract: This paper presents a new magnetic levitation spherical reluctance driving joint. It analyses the theory of air-gap magnetic of the driving joint and the mechanism of the generation of the magnetic levitation force and electromagnetic torque which based on the principle of reluctance motor. The mathematical model and the inverse system decoupling model of the driving joint have been established. The decoupling linearization and the state feedback closed-loop control system have been achieved in this paper also. The research of the result of system simulation provides us the decoupling characteristic and the dynamic characteristic of the driving joint system.

Abstract: To describe precisely the performance characteristics of Markov repairable systems, the model of Markov repairable systems with multi-operating state was introduced. There are three kinds of states of the system: normal, abnormal and fault state. The system works when it is in the normal state and abnormal state, it stops to be mended till it is inspected and diagnosed in abnormal state or something wrong happens in it. Inspect it at intervals after it begins to work in the normal state until it is inspected and diagnosed in abnormal state or it fails. The life of the system, inspection time intervals and repairing time follow exponential distribution, we build the Markov mathematic model to the system. The steady-state reliability and the expression of steady-state yield are derived by using the Markov process method. The study of numerical examples has shown that optimal inspection strategy can increase the system economic effectiveness.

Abstract: This article studies the embedded SPC and its application in roundness measuring system by analyzing the current roundness measurement principle and technology. With analyzing the process of data collection, date treatment and various kinds of tool graphic construction, we study the feasibility of integrating SPC into roundness measurement and finally apply the embedded SPC as pure software into roundness measuring system. We design the roundness measuring system based on embedded SPC and develop the roundness measuring system of low power consumption, high accuracy and easy application, which is suitable for industry field usage.

Abstract: This paper presents a spherical switched reluctance motor with magnetic levitation on the basis of suspension theory and minimum reluctance principle. The elements and mechanism of the spherical switched reluctance motor with magnetic levitation, deduces and calculates the magnetic conduction of the gap by means of the magnetic segmentation are analyzed, and a mathematical model of spherical motor is obtained. With the Matalab/simunik simulation, the results show that the rotor realizes quick stable suspension and rotation, and has excellent antijamming performance as well.

Abstract: To raise the programming efficiency of arc welding robots, the offline programming system was developed for a Motoman-UP20 robot with redundant degrees of freedom in VC++ integration environment. The system consists of kinematics analysis, motion simulation, welding trajectory plan, welding parameters plan and job file generating module. It can plan the motion path and posture of welding gun for saddle-shape seams, and display the workpiece on the interface synchronically. Job instructions can be made step by step, or generated automatically. Kinematics simulation module and communication module are integrated together, and job files can be exchanged between PC and robot controller via Ethernet to realize remote control.