Applied Mechanics and Materials Vol. 742

Abstract: A water-saving irrigation monitoring system was designed based on ZigBee wireless sensor network and LabView simulation platform. This system can solve the problems of unnecessary waste caused by the traditional artificial irrigation water and wiring complex of water-saving control system. The information of each node and data acquisition can be detected by the ZigBee wireless network monitoring system. Upper machine was designed by LabView virtual design platform, and all aspects of organic characteristics of the crop water requirement rule were combined through the fuzzy control decision support system. The date of the irrigation water would be directed, and achieved a fine management of water and scientific irrigation.

Abstract: In this paper, a strategy for estimating the induction motor’s rotor speed is proposed. The proposed rotor speed estimation strategy is based on model reference adaptive identification theory. By applying the proposed strategy, the induction motor control system can estimate the induction motor's rotor speed precisely. To improve the rotor speed estimation performance of the system, two methods have been adopt. The speed sensorless control system based on proposed strategy was built with Simulink blocks in Matlab platform. The corresponding simulation results demonstrate that the proposed method can operate stably in the whole range of speed with preferable estimation precision of stator resistance and rotor speed.

Abstract: As the number of handicapped people increases worldwidely, the role of electric wheelchair becomes important to enhance their mobility. In the relevant community, attention is mainly directed to how to solve the problems in motion control for the wheelchair users, and scarce reports have appeared concerning obstacle avoidance of wheelchair. In this paper, we present a new method of obstacle avoidance for omnidirectional intelligent wheelchair bases on multi-sensors information fusion. Distance information acquired from ultrasonic sensors and visual information acquired from monocular camera are combined together, in which optical flow method is employed to distinguish obstacles. Extensive experiments have been conducted in the laboratory. As shown in experimental results that, the developed omnidirectional intelligent wheelchair works correctly and effectively in obstacle avoidance.

Abstract: In this paper, a new jetting dispensing system for underfill process is proposed and experimentally evaluated. The suggested system is actuated by two piezostack actuators positioned in parallel and a lever-hinge mechanism is used for amplifying a displacement of the piezostack actuators. After describing the geometric configuration and working principle of the proposed system, both geometric and material information are explained. In order to evaluate the performance of the proposed system experimentally, an experimental apparatus are manufactured. The needle displacement and jetting weight of single dot are experimentally obtained and displayed.

Abstract: In order to decrease the temperature error of MEMS gyroscopes, a mitigation method based on gyroscope array was proposed. Angular rate of MEMS gyroscope fluctuates dramatically with the change of gyro temperature when gyroscope starts up. The temperature characteristic error of MEMS gyroscope has become one of the major errors in the practical application. A mitigation method for temperature error was presented based on MEMS gyroscope array utilizing high correlation of temperature errors in the same batch of MEMS gyroscopes. This method was designed to improve environmental adaptability and shorten the startup time of MEMS based inertial measurement unit. Experimental results showed that the method was feasible and effective.

Abstract: The gyro-stabilized platform is one of the key parts of a guidance weapon. The structure performance of a platform influences the accuracy and reliability of the guidance weapon straightly. In order to reduce development cost and time, the structural modeling and analysis of gyro stabilized platform is very necessary. UG software is applied to establish the three-dimensional model of a platform firstly. And then some components are simplified using MSC Patron. According to the different connection mode between the components, some appropriate connecting elements are applied to establish the finite element model of the platform. In order to meet the special requirements of individual components, appropriate materials are selected so that the finite element model is closer to the actual situation which ensures the reliability of mode analysis and optimized computing results. The work in this paper provides reference for establishment of the similar structure finite element models.

Abstract: The aircraft recovery systems have been drawn more attention for its ability on offering cushioning landing in recent years. However, many previous researches mainly focus on the cylinder or rectangle air bags where the upper surface is orthogonal to the flank side. This kind of airbag will not meet the requisite stability and security because it might be bended by payload under the misalignment forces. In this light, a more stable frustum of cone parachute-airbag system is proposed and the cushioning mathematical model is established. Based on the theories of thermodynamics and mechanics, the expressions of velocity and deceleration are derived. The effects of initial parameters on airbag cushioning properties are analyzed and the simulation results are shown. The results can provide references for the future design of aircraft recovery system.

Abstract: The fuzzy adaptive PID algorithm in MATLAB is packed to VB and applied to engineering practice without Matlab environment, it is called like internal strategy in configuration software, it lays the foundation for the intelligent control strategy in the configuration software and online simulation control system.

Abstract: Sets up a nonlinear vehicle dynamic model of eight degrees of freedom and simulates in Matlab/Simulink environment using three anti-lock braking control algorithms, which contain PID, logic threshold and sliding mode variable structure. On the basis of the work, the improving effects for vehicle directional stability, the control effects analyzing from the aspects of tire/whole vehicle parameters and the phase-plane of slid slip angel and its rate are compared and analyzed. The results show that: PID responses fastest but with larger overshoot, logic threshold has smallest fluctuations thus can be implemented more easily, sliding mode control responses slowest but can hold the slip rate more accurately.

Abstract: In order to further strengthen the management of open laboratory in colleges and universities and improve the utilization rate of equipments, we design and develop a kind of laboratory management system based on embedded video and campus card. Among it, the video monitoring module combines with the embedded technology, image processing technology, internet communication technology and so on, which is used to achieve real-time display and remote video monitoring in the laboratory; campus card is used to implement the student identity authentication, laboratory access control and power supply management.