Applied Mechanics And Mechanical Engineering

Volumes 29-32

doi: 10.4028/

Paper Title Page

Authors: Cui Ping Shi, Bai Rui Tao, Feng Juan Miao
Abstract: An efficient gait recognition approach based on wavelet descriptors (WDS) is proposed. First, gait silhouette is described by WDS. Second, the PCA is applied to reduce the dimensionality of the input feature space. Then, the similarity of training samples and test samples is calculated. Finally, sequences matching are used to get the correct identification rate. By utilizing the proposed approach, the experiments made on CMU database have achieved comparatively high correct identification rate. And related experiment results show that, in the same conditions, the correct identification achieved by WDS is generally higher than the method of Centroid and FDS.
Authors: Jian Lu, De Mn Xu, Li Chuan Zhang, Fu Bin Zhang
Abstract: Cooperative navigation of multiple Unmanned Underwater Vehicles(multi-UUVs) is an important approach to solve localization problem of UUV formation. This paper expatiates on the popular cooperative navigation modes of Leader-Fellow structure and Moving Long Base Line(MLBL) structure, and provides the motion equations and the measure equation based on hydroacoustic Time-Of-Flight(TOF), and studies on the cooperative navigation methods which make use of two nonlinear filters of EKF and UKF. It is an obvious conclusion that adopting cooperative navigation methods can improve effectively localization accuracy of UUV equipped with low precision navigation sensors.
Authors: Cheng Jiao Tu, Xue Zhe Wei, Hai Feng Dai
Abstract: Electric vehicles have the ability to drastically reduce petroleum use. As the battery used in EVs appears to be the main technical barriers both from a performance and cost perspective, the main efforts have been focused on how to select appropriate power train system for the better dynamic performance. This paper introduces some methods of parameters design of EV’s main power train components, such as the lithium-ion battery and AC induction motor. Then we build a battery model, a motor model and vehicle simulation models using ADVISOR software. Meanwhile, this paper proposes simulation results of the entire vehicle’s dynamic performance, which shows that the power train components’ parameters designed here basically meet the vehicle’s requirements.
Authors: Xue Yu Chang, Ze Chang Sun, Xue Zhe Wei
Abstract: Vehicle safety is a very important design element for all types of vehicles designed for use on public streets or roadways. Traditional vehicles produced with liquid fuels have a long history of creating appropriate safety countermeasures. With the onset of new electric propulsion and charging systems, proposed for large scale production, new safety design elements will need to be provided to vehicle developers. This paper attempts to summary the usually protective measures against electric shock on electric vehicles and to analyze these measures to formalize a series of important safety references for vehicle developers.
Authors: Wei Liu, Zi Yun Lu
Abstract: This paper is concerned with the asymptotical stability analysis for a class of switched uncertain descriptor systems with time-delay. The robustly asymptotical stability of this system is proven by making use of the generalized Lyapunov Stability theory, linear matrix inequality (LMI) tools and multiple Lyapunov function techniques. The conservation of result is greatly reduced by means of introducing the optimal weight matrix and avoiding vector matrix inequality in deducing procedure, in which there is no need of transformation and hypothesis for descriptor systems. The designed control law could surely make switched Descriptor Systems quickly approach the balanceable point. Experimentally, one numerical simulation verifies the effectiveness of this method.
Authors: Ren Liu, Dong Xiao Niu
Abstract: As information technology is widely used in electric power field, security risks penetrate into all aspects of electricity production and operation, meanwhile, complexity of electric power information system make it's very difficult to guard against security risk. Information security risk assessment is the foundation and the precondition of information system security. In this paper, combining long-term power information security supervision practice, we give a multi - hierarchy and multi - attribute index system of information security risk evaluation, and point out these indexes are characterized with grey, fuzzy and difficult to quantify. Then, the analytic hierarchy process (AHP) and the theory of grey system are introduced in setting up a comprehensive evaluation model, we obtain the final score using the information fusion of different experts. Additionally, an application example is used to illustrate the availability of the proposed evaluation method. The result shows that grey evaluation which combines advantages of the qualitative and quantitative methods can be applied to risk evaluate of information system more accurately and scientifically. Meanwhile the evaluation results can help supervisors judge which is the necessity to improve.
Authors: Ling Fei Xiao, Shao Dong Duan, Tao Shen
Abstract: In this paper, a novel time-varying sliding mode control (SMC) algorithm based on sliding mode prediction for a class of discrete-time nonlinear uncertain coupled systems is presented. After giving a kind of time-varying sliding mode function, a sliding mode prediction model is used to predict the future information of sliding mode. By employing feedback correction and receding horizon optimization approaches which are extensively applied in predictive control strategy, the desired discrete-time variable structure control law is obtained. Under the influence of uncertainties whose boundaries are unknown, the closed-loop systems are proofed to be robustly stable. Numerical simulation results illustrate that compared with conventional SMC method, under the algorithm proposed in this paper, chattering is eliminated, the control signals have smaller peak values, and the closed-loop system possesses stronger robustness.
Authors: Xiao Li
Abstract: A master-slave control method based on the identifications of load force and impedance for Tele-operated hydraulic construction robot system is presented in this paper. The robot system is composed of a hydraulic excavator and two joysticks. The hydraulic excavator is served as the construction robot. The joysticks are used for operating the robot in a remote region. The master actuator and the slave actuator in this system are the joystick-gear of a joystick and the fork-glove actuator of the excavator respectively. The load force and impedance identifiers are used for identifying the load force and impedance of the slave actuator respectively. According to the load force, the master controller controls the master actuator to generate the reaction force for operator. On the basis of the load impedance and the master slave error, the slave controller controls the slave actuator to perform a working task. The experimental researches confirmed that the operator not only obtains the force sense of the object accurately, but also obtains the deformation and stiffness senses of the object obviously.
Authors: Wen Jin Dai, Hai Jing Liu
Abstract: Variable speed constant frequency wind turbines can get the maximum power by adjusting the rotor speed of the induction generator according to the variable wind speed. The mathematical relationship between wind speed of wind generation and power of wind turbine power is studied in this paper, then control strategy of maximum power point tracking consists of comparative law of the greatest power, table look-up scheme of the best tip speed ratio and a variable step mountain climb algorithm and the like., and advantages and drawbacks of them are compared. Finally a variable step mountain climb algorithm for an induction generator is studied and the wind turbine model is tested by MATLAB simulation. System simulation results have confirmed the functionality and performance of this method.
Authors: Y. Wang, Y.H. Dong, J.Y. Qiao, Li Ma
Abstract: The paper puts forward a two-stage model of state prognosis based upon measured vibration monitoring information to date. First the two-stage operating process of equipment is described. Secondly, the modelling method and process of the two-stage state prognosis model is given. At the same time, the estimation method of unknown parameters in model is also given. Last the model is applied to predict the residual life of a set of rolling element bearings based on their vibration monitoring information.

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