Advanced Materials Research Vols. 433-440

Abstract: This paper presents a new strategy for the trajectory tracking control of robot, using a fuzzy logic approach and sliding mode control. The key properties of sliding mode control are robustness and chattering which are greatly affected by the motion quality of the reaching phase. The reach law is taken to determine the control law which can improve the convergence speed in the reaching phase and impair the chattering.A fuzzy logic controller is taken to adjust the parameters of the reach law timely which makes the system have a high and rational reaching speed during the whole reaching phase. The error convergencing speed is enhanced which boosted the robustness of system indirectly. And the reaching speed is reduced enough to impair the chattering when the system is very near the sliding mode surface. At last, both the robustness and chattering are improved. A mobile manipulator with two arms is taken as an example to track a given trajectory with the proposed controller. It is found that the results are very encouraging.

Abstract: For specific mission and unique configure of Shipboard Electrical Power Systems (SEPS), their relay protection schemes are different from Terrestrial Electrical Power Systems (TEPS). With development of system capacity and network topology, the traditional three-step current protection method can not meet protection demands, which has the feature of off-line setting. Based on the characteristic and requirement of SEPS, a new short-delay adaptive current protection scheme is proposed, which can automatically adjust current settings of short-delay protection on-line according to the system operation state. Simulation results of typical instance verify the feasibility and validity to improve protection performance.

Abstract: In this paper, the compound control algorithm of fuzzy and PID has been applied in Acceleration Slip Regulation for vehicle to prevent the excessive spin of driving wheels on wet or icy roads. Simulation experiments have been done to investigate the performance of Acceleration Slip Regulation. The results show that the provided Fuzzy PID controller can effectively keep the slip ratio of the driving wheels in the optimal range and improve the driving ability of the vehicle.

Abstract: The application of the lossless data compression technology in the filed of telemetry system is discussed in this paper. Based on the ARC algorithm, a real-time lossless data compression technology is proposed. By combining the TMS320C6416 and XC3S200AN FPGA, this paper designs a real-time lossless data compression device hardware system. 2048 bytes of some telemetry noise data can be compressed in 5.64ms in this system and the compression removal rate reaches 78%. What’s more, the system has solved the problem of data capacity and speed during the process of data compression , which greatly improves the efficiency of data compression.

Abstract: Fire seriously affects people's lives and property, a large space building early fire detection and fighting has always been an international problem. Combining image recognition and processing technologies, intelligent control technology, we design an image-based intelligent fires fighting monitor system. Using this system, able to automatic pursuit fire, automatic alarm, timely and effective fixed fire-fighting in a large space. Can be used to protect the larger, higher risk important places. The system network flexibility, expandability, has been successfully applied to many practical projects.

Abstract: Based on GPS positioning technology，taking ARM920T core S3C2440A processor as the control core, complete the design of blind navigation. The navigator can be more accurate to tell the current time, direction, location names and other detailed information for the blind and their families by means of voice broadcast and liquid crystal display, the system easy to operate, simple and greatly enhanced the bind’s ability to walk around, better usability, may become widely used by the blind.

Abstract: Due to the rise in demand for portable electronic device, low power and low voltage circuit design is extremely important for the appliances like computers, laptops, mobile phones and etc. Low power dissipation results in longer battery life and better integration density. This can be achieved by designing a modified low voltage op amp. The design of low voltage op amp in this paper is the combination of several low voltage analog cells. The modified low power op amp in this paper is built based on low voltage basic op amp. In this paper, the design objective is to achieve certain criteria such as supply voltage as low as 1 V, high gain more than 40 dB, low power consumption and high bandwidth. The use of FGMOS would increase the operating range of op amp through programming the threshold voltage of the FGMOS. This project is simulated using Silvaco Gateway and Expert.

Abstract: Hopf bifurcation is regarded as one of the three kinds of bifurcations which can cause voltage instability. The Hopf bifurcation was obtained if a pair of complex conjugate eigenvalues of Jacobian matrix crossing the imaginary axis. To calculate the critical eigenvalues of bulk power system, a restarted-refined Arnoldi method is introduced. The refined Ritz vectors are used as the approximations based on the refined projection theory in order to enrich the information of the eigenvectors in the projective subspace. Two examples indicate that the method can work out a set of conjugate eigenvalues which will show whether the Hopf bifurcation appears and provide the datum for the dynamic voltage stability analysis ulteriorly.

Abstract: Cogging torque is one of the most important parameters of permanent magnet motors, which causes torque ripple, vibration and noise. This paper describes the mechanism of cogging torque, introduces several methods of reducing cogging torque and points out the advantage of novel magnet arrayed permanent magnet motor in reducing cogging torque. Ansoft software is used to build the simulation of conventional surface-type permanent magnet motor and novel magnet arrayed permanent magnet motor and to calculate their cogging torque. a cogging torque testing system which included the angle sensor, permanent magnet motor, torque wrenches and other components are tested two different structures motors’ cogging torque .The experimental result is consistent with the simulation results, it shows that the method of novel magnet arrayed permanent magnet motor reducing cogging torque is correct. The new method compare with the same specification on the surface of permanent magnet motor can reduce more cogging torque.

Abstract: A time-difference-of-arrival (TDOA) positioning technique for indoor ultra wideband (UWB) systems is presented. Non-line-of-sight (NLOS) propagation error is a major source of error in positioning systems. Therefore an NLOS mitigation technique employing a Kalman filter is utilized to reduce the NLOS errors in indoor UWB environments. An extended Kalman filter (EKF) is used to process the TDOA data for mobile positioning and tracking. Performance results are presented which show that the proposed scheme can significantly improve the positioning accuracy in a UWB environment.