Applied Mechanics and Materials Vols. 568-570

Abstract: There are a great amount of electronic meters equipped in the distribution substations, which were traditionally monitored by operators. On-site monitoring for risk assessment of these meters is very important. In this paper, we presented an advanced machine vision based automatic meter detection method toward the development of an online automatic meter reading intelligent inspection robot in substation. Firstly, the image received from the inspection robot was enhanced using histogram equalization. Then, the image was segmented into two parts based on the threshold obtained by Otsu’s method. Using these two parts, and the whole enhanced image, circular Hough transformation was applied on these three images and detected the circle with highest probability on them. The normalized correlation coefficients were calculated between the corresponding areas of those three circles from three images and the template image of SF₆ meter. Finally, the circle with highest correlation coefficient, which was higher than a certain threshold, was determined to be the meter. If it is lower than the threshold, the algorithm would decide that no meter was found in the image. The method was tested with 222 images obtained in one substation in Xi’an, Shanxi, China, and an 87.4% accuracy was achieved using these images, which indicated the potential of this method.

Abstract: Compared to conventional navigation signal simulators, software simulator has many advantages, which include flexible design, easy extending, strong openness, and low cost. With the development of satellite navigation, satellite navigation system is getting more and more complicated. Based on the analysis for satellite navigation signal model in different modulation methods of multisystem, it is very urgent to establish a unified description method, which can reduce duplication writing of algorithm. firstly, description method for multisystem satellite navigation signal simulator is proposed. Secondly, it can describe different systems of satellite navigation signals and provide estimation method for signal transmission delay time and Doppler frequency shift. Finally, the signal of simulation is validated.

Abstract: The establishment of the target model is the key of maneuvering target tracking. The previous research on interactive multiple model, which is applied on tracking extensively, focused on the design of the model set and fusion with other algorithms, while there is less study on change mechanisms of the model weight. In light of this, the impetus behind this paper is to do some analysis which based on the model weight of different trajectories, reveal the change rule. Finally, the validity of the proposed approach is demonstrated by simulation.

Abstract: Aerodynamic parameter identification technology is an important method to get the aerodynamic parameter of flight vehicles. The mathematical models of flight vehicles are generally nonlinear form. In order to remove the model error caused by linearization, the output-error method has been adopted to identify the aerodynamic parameters in the longitudinal nonlinear model of an UAV (unmanned aerial vehicle) in this paper. Longitudinal nonlinear state and output equations of the UAV are established. Then simulation data of longitudinal nonlinear model with measurement noise is used to verify this method. The results show that the unknown aerodynamic parameters in the nonlinear model can be effectively identified by this method.

Abstract: To track the moving target with the nonlinear and non-Gaussian state in real time, we in this paper apply particle filtering theory in the antenna tracking system. After the prediction of the target state, the antenna attitude is regulated in real time by the servo control loop so that the antenna can aim at the target precisely. The particle filtering can efficiently improve the tracking performance of the antenna tracking servo system affected by the delay time in comparison with Extended Kalman Filtering. The system performance is verified by a numerical simulation of maneuvering target tracking.

Abstract: In view of badly transplanting of analog filter and low cost performance of digital filter for the washing out signal methods used by dynamic simulator, this paper proposed a computer intelligent time domain method. We decompose signal with the computer intelligence in the time domain, and convert the signal into the corresponding movement form respectively, then get the final result by overlaying them. The experimental results show that this method not only can achieve the effect of the traditional methods, better portability and faster computation speed, but also can be achieved directly on general computers.

Abstract: Fast-steering mirror system demands higher accuracy and fast responding speed to track targets, but the conventional PID controllers cannot meet the demands. Instead, the fuzzy PID control can greatly improve the capturing and tracking capacities to high-speed dynamic targets. So we apply the fuzzy-PID controller in the positioning loop of the stabilized system, not only improving the transient process of the control system and decreasing the overshoot, but also enhancing the accuracy of tracking stabilization and response. At the end, simulations were performed to test the effectiveness of this method through the MATLAB platform.

Abstract: The electro-hydraulic load simulator is an important equipment for aircraft hardware-in-the-loop simulation. An adaptive PID control method for compensating extraneous torque with simple structure and easy to implement is proposed according to the variation characteristics of load gradient in the load simulator. The control parameter tuning method is also given.

Abstract: Since the solving process of hydraulic dynamic simulation is complex and computational ineffectiveness,the aero-engine actuators real-time modeling is presented in this paper. Combined with the precise model, the convergence of the model and flow coefficient is analyzed. The real-time model operates a number of solving processes in one 20ms simulation cycle and the convergence of fix-step algorithm is guaranteed by adjusting the relevant parameters. The simulation shows that the real-time model can improve the computational efficiency with satisfactory real-time performance and precision.

Abstract: In this paper, a new automatic variable transmission (AVT) is studied. This AVT is made up of two parts, which include the metal belt continuously variable transmission (CVT) and gear transmission. And the CVT mode is used in the low speed and the gear transmission is used in the high speed. The software of simulationX is used to build a simulation model for the AVT vehicle, and the system dynamics characteristics of AVT are studied via this model. Compared to the CVT vehicle in terms of the maximum speed, the accelerate time and fuel consumption, the AVT vehicle develops the advantage of CVT in the low load and improves the weakness of low power in the high load. The results of this paper show that the AVT vehicle has good dynamics performance at the whole work area, which can advance the transmission efficiency and improve the fuel economy of the vehicle.