Advanced Materials Research Vols. 846-847

Abstract: Internet routers play an important role during network congestion. All the routers have buffers at input and output ports to hold the packets at congestion. Various congestion control algorithms have been proposed to control the congestion. Recently, some proportional-integral-derivative (PID) controller based algorithms have been proposed as Active Queue Management (AQM) schemes to address performance degradations of end-to-end TCP congestion control. However, most of the proposed PID-controllers for AQM are validated for their performance and stability via intuitive explanation and simulation studies instead of theoretic analysis and performance evaluation. But there are a few drawbacks of PID-controller based AQM algorithms leading to poor performance like causing data retention dropping and oscillation when the time delay is large, which means that the existing PID-controller can not meet the Quality of Service (QoS) requirements. To overcome the drawbacks of traditional PID, we analyze and enhance the PID-controller based AQM algorithm by regarding the TCP congestion control mechanism as an input-rate based Adaptive Fuzzy Neuron PID control algorithm (IRAFNPID) to avoid congestion in TCP/AQM networks. By means of simulations, we evaluate and compare the performance of traditional PID, single neural adaptive PID(SNAPID) and IRAFNPID, simulations with experiment data analysis and find that IRAFNPID has better convergence, stability, robustness, goodput and lower loss ratio.

Abstract: The objective of this work was to investigate the concept of knowledge in order to obtain useful for the techniques of artificial intelligence and knowledge representation. several definitions of knowledge proposed by various authors are analyzed, compared and graded, they are then merged into a new definition, which is partially formalized tools logical-algebraic, and finally, discusses the possible links with the areas of intelligence artificial intelligence and knowledge representation.

Abstract: The ultrahigh frequency (more than 1MHz) of the HF Induction Heater need to be reached for surface-heat-processing of tiny mental components, which is not available by the traditional HF Induction Heater. To satisfy these requirements, by using the high-speed field effective transistor (FET) and high-speed phase locked loops (PLL: MM74HC4046), the frequency of inverts for induction heater and the power can arrive at more than 1MHz and 5.5kW respectively at the same time. Additionally, it achieves the power adjusting technique and the frequency tracing. The experimental shows that this design can both achieve the high frequency and efficiency, and meet the requirement of the surface-heating-process of the tiny components.

Abstract: This paper deals with the tracking control problem of attitude angles for a four-rotor helicopter with external disturbance. A new direct adaptive compensation controller and its parameter adaptive laws are designed based on the Lyapunov stability theory, and the designed contorller can not only compensate the disturbance efficiently, but also can make the attitude angles of the four-rotor helicopter track a given reference output. By using the Barbalat lemma, the systems state tracking performance is proofed. Finally, the proposed adaptive technique is evaluated by a simulation example.

Abstract: The 15 DOF four in-wheel motor electric vehicle model is developed based on Matlab / Simulink. The model adopts modular design. The dynamic model equations, vehicle model diagram and the methods of each module modeling are presented. The model is verified by commercial software Carsim. The results show that the model is higher accuracy and it can be used for the control algorithm improvements and validation as a good platform.

Abstract: In the vehicle stability control and other active safety systems, vehicle sideslip angle real-time estimation is necessary. However, the direct measurement of sideslip angle is more difficult or too costly, so it is often used in estimating methods. The vehicle sideslip angle of closed-loop Luenberger observer and Kalman observer were constructed based on two degrees of freedom bicycle model, as well as the direct integration method for large sideslip angle conditions. The comparative study showed that Kalman filtering estimation method and Luenberger estimation methods have better estimation accuracy in small slip angle range.

Abstract: A kind of vehicle active suspension based on Electro-Hydrostatic Actuator (EHA) is put forward. The suspension system consists of two parts: spring and actuator with controlled force. The actuator includes hydraulic cylinder, hydraulic pump, controller, etc. In this paper, a quarter-car dynamic model is exactly established involving bond graph models of EHA parts. Under the input conditions of the given road profile and designed sky-hook controller, The prototype and test rig of EHA active suspension are developed and bench tests are carried out. The simulation and experimental results show that sky-hook active suspension with EHA provides better ride comfort, handling and stability than passive suspension.

Abstract: The error sources of machining accuracy of CNC machine tools including geometric error, thermal error, system error and error of load control etc. The error source affect the relative position of the cutting tool and the workpiece by the dynamic motion, and then affect the machining accuracy of the workpiece. By trial cutting method, "S" test part is a new test part for detecting machining accuracy of five-axis linkage machine tools. Through experiment and simulation, identification of the error source of the machining accuracy and the regular of "S" test part surface errors, surface quality, results show that "S" test part can reflect the machining accuracy of CNC machine tool.

Abstract: This paper presents a new constant tension control device which is suitable for warping of the carbon fiber or the flake yarns which are zero twist, high tensile strength, low shear strength, high specific modulus and self-lubrication and can meet the requirements of the warp tension of the carbon fiber multi-layer weaving equipment which is in the process of development. The device can make yarn tension consistent in warping process. Especially with the decrease of the diameter of yarn tube, the tension of yarn sheet is consistent in warping process. In the process of warping the warp doesnt twist and wear is small. The experimental results show that the mechanism can realize accurate control on the tension of the single yarn and the yarn sheet, and is able to meet the requirements of the warp tension of the carbon fiber multi-layer weaving equipment which is in the process of development.