Applied Mechanics and Materials Vols. 347-350

Abstract: A design of mechanical arm for laser weeding robot is described. The long term objective of the project is the replacement of chemical weeding by laser weeding. The distinguishing feature of this design is the use of a mechanical arm, which is equipped with a laser generator and a control center consisted of a single chip microcomputer and two driver hybrid ICs. The mechanical arm comprises two stepping motors vertically linked together. The robot moves ahead one step, the working area of laser generator is divided into 10×10 grids. Through the inverse operation of mechanical arm, the motor displacement angle of each grid is calculated. Mechanical arm turns to designated position if single chip gets weeds position information. The result of the design is a key executive mechanism of laser weeding. The operation error of mechanical arm is analyzed. The arm can point the laser beam towards the target weeds with small error. After the order of the execution areas is optimized, the length of arm moving path is shorter. Analysis of the running track shows that the sequence of execution area is feasible and reasonable.

Abstract: Although peoples legs are capable of a broad range of muscle-use and gait patterns, they generally prefer just two, walking and running. A popular hypothesis regarding legged locomotion is that humans and other large animals walk and run in a manner that minimizes the metabolic energy expenditure for locomotion. Here, a mathematical model for a simple two-dimensional planar kneed walker with point feet and two bended knees is discussed. An energy-effective gait is designed by using piecewise torque method. Then, the robot model can exhibit a natural and reasonable walk on a level ground. The results can prove that the proposed optimal energy-effective gait is suitable for this kneed biped walking robot. And we also discover some walking rules maybe true through the results of optimization.

Abstract: Rate control is the core issue to realize video encoder, and it is also one of the key factors determining the quality of video code system. Given the MAD (Mean Absolute Difference) prediction and the drawback of bit rate control in the BU (Basic Unit) layer, improvements are put forward on the basis of analyzing and researching the G012 rate control algorithms in this paper. In this paper, we proposed a new video bit rate control algorithm to overcome the drawback of bit rate control in the BU (Basic Unit) layer. Combined with the image brightness gradient value to estimate in the MAD prediction, the allocation encoding bits method based on the PSNR (Peak Signal to Noise Ratio) is proposed in the rate control of BU layer. The experiment results show that compared with JM algorithms in H.264 standard reference software, the improved algorithm is enhanced in the PSNR.

Abstract: Time delay and packet loss rate during the network video transmission are the two important factors in network video transmission quality. The purpose of congestion control is to reduce the bad impact of network video transmission quality caused by time delay and packet loss rate. This paper proposed a network video transmission quality assurance algorithm based on unbalanced multiple descriptions coding scheme. The new algorithm predicts the congestion state of network by means of Markov model based on available bandwidth detection, changes video transmission path on the basis of the prediction. Experiments show that compared with RED (Random Early Detection) algorithm, the algorithm is much more effective to estimate network congestionreduce video packet loss rate and time delay, thus the network video transmission quality can be ensured more effectively.

Abstract: To suppress the noise effect on the performance of local mean decomposition (LMD) in signal processing, a new method combined with singular value decomposition (SVD) denosing was proposed in this work. SVD is applied to denoise the observed signal, and then the signal decompose to series product functions (PF) by LMD, meanwhile, SVD is applied to denoise the PF and sum the PF to LMD again. This method can suppress the noise effect to attain high precision PF for time-frequency analysis. Simulation signal and telemetry vibration signal processing results show the effectiveness of the method.

Abstract: Joint detection (JD) is a core technology of TD-SCDMA system. Only many mathematical models of JD have been proposed and discussed in many references, but there is no a physical model of JD for application. So the concept of JD is not clear. The concept of JD is made clearer by its principle and algorithm with physical model presented in this paper. Also a method for eliminating multi-path interference (MPI) by using mid-amble sequence and frequency spreading code (FSC) would be presented, and a JD constructed by that method would be proposed in the paper.

Abstract: The existing hydraulic pressure control fault diagnosis system is effective on fault detection, but the fault isolation capability is bad. In order to improve the capability of the fault isolation, the artificial neural network (ANN) is used in the fault diagnosis system. Aimed at the representative diagnosis of the hydraulic pressure control system, the three layers feedback network is adopted, the basic theory of conjugate gradient BP neural network is explained in detail, and the key techniques are introduced. Five types of typical faults of hydraulic pressure control system can be distinguished easily by it, the faults diagnosis efficiency is higher 30% than ever and the fault diagnosis capability is better 80% than before.

Abstract: During the design of IVECO ISG hybrid electric vehicles (HEVs), the ISG electrical propelling system was inserted into the Duling IVECO vehicle. Thus the controller of ISG electrical propelling system constructed the distributed control system with the other controller. However, field bus is one of key techniques in the distributed control system. Firstly, CAN communication protocol for ISG controller based on the SAE J1939 CAN bus protocol was presented, then the hardware and software of ISG controller was designed in modular.

Abstract: In this paper, we discussed this engineering problem that used planar capacitance sensor measuring lumber moisture content. And a new mathematical model was introduced which could set up the relationship between the distribution of dielectric constant and planar capacitance sensor in the heterogeneous asymmetric cases. At the same time, the numerical example was given and we matched the function of capacitance value and dielectric permittivity of medium. Accordingly, through measuring capacitance value of capacitance sensor, we could get the distribution situation of dielectric permittivity, thus obtaining the moisture content distribution of media such as wood. It could not only greatly cut down measuring work, but also avoided the waste of media resources, such as wood.

Abstract: In order to improve the reliability, security and validity of such type Missile Launcher, The faults prediction theory is introduced based on fuzzy neural network. The faults prediction analysis model is built, and an advanced training algorithm is proposed. Such algorithm is tested by using in the fault prediction of the missile launcher. The Experiment results illustrate that by using the proposed model, the faults prediction speed is faster 80% than ever, the prediction veracity is advanced, and the cost is reduced to 50%.