Applied Mechanics and Materials Vols. 303-306

Abstract: The water bath drawing slot in carbon fiber production is a MIMO system with coupling and time delay. It is difficult for a traditional control scheme to realize stable control on the water bath drawing slot. In this paper, a model-free adaptive control based on particle swarm optimization (PSO) algorithm was designed with few parameters, convenient control, and without decoupling. The PSO algorithm was used to adjust MFAC controller parameters online at each sampling time. The proposed method was applied to the liquid-level-concentration control in the water bath drawing slot of carbon fiber production. The control method has rapid response time, good decoupling and performance by comparing with model-free adaptive control and traditional PID control.

Abstract: This paper elaborates on the analysis and simulation of a megawatt Wind Turbine (WT) driving low speed Permanent Magnet Synchronous Generator (PMSG) based on Current Source Converter (CSC) using PSIM computer simulation program. The system consists of wind turbine, PMSG, maximum power point tracking (MPPT) and three-phase CSC models. In the WT model, the best performance coefficient has been determined according to the variable wind speed with MPPT control. The gear-box has been eliminated by the low speed PMSG to achieve high efficiency. The ac power output from PMSG is fed to a three-phase CSC, which extracts maximum power through closed-loop regulation of generator speed. The current source PWM inverter is used to interface the system with the electrical utility. The available maximum power fed to the grid is adjusted by regulating dc-link output current of CSC according to the variable wind speed.

Abstract: The current Proportion Integration Differentiation(PID) optimization design methods are often difficult to consider the system requirements for quickness,reliability and robustness.So an Improved Genetic Algorithm(IGA) is proposed.The new method of generating the initial population,adaptive change of crossover and mutation probability and effective selection strategy are used to optimize the parameters of PID controller. The simulation experiments with Matlab prove the new approach is valid.

Abstract: A robust receding horizon control (RHC) scheme is developed for uncertain discrete-time Markov Jump Linear Systems (MJLS) with time delay and actuator saturation where the system uncertainties and jumping transition probabilities are assumed to belong to some convex sets. Firstly, when time delay is considered, a sufficient condition of minimizing upper bound of the cost function and mean square stability of the closed-loop system are established based on the Lyapunov Krasovskii function which depend on the current time jump mode. At each sampling time, an optimal control gain can be obtained by solving the semi-definite programming (SDP) problem. Then, the proposed strategy is extended to design robust RHC scheme for uncertain MJLS with both time delay and actuator saturation. Moreover, the domain of attraction can be estimated through a modified invariant ellipsoid. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the proposed method.

Abstract: Used Atmega 8 microcontroller as the control center, with the temperature sensor DS18B20, feeding control system, combined with radio frequency technology, intelligent control system for fish-farming was designed. The system has the whole process of intelligent automatic control and testing for feeding, supplemental oxygen, and PID temperature regulation; PC and the host processor connect each other through the RS-485 to greatly improve the transmission distance, using CRC cyclic redundancy check code ensure the accuracy of data. The machine is mainly responsible for collecting the spot parameters such as temperature and transmitting the data to the host processor, and send data to PC by the host processor through the serial port to display. Using GSM short message service directly sends the relevant data to the console or the owner of the mobile phone, so as to realize the entire fish process automation management. The system can be widely used in families, and pond pisciculture, and provides the owners efficient and convenient services.

Abstract: In order to improve the speed performance of permanent magnet synchronous motor(PMSM) speed control system, and increase system reliability and adaptability, PMSM current-speed double close loop speed control system based vector control was designed. Current loop adopted traditional PI controller, speed controller adopted adaptive fuzzy PI control method which was based on traditional PI control method and fuzzy control method. Space voltage pulse width modulation (SVPWM) technology was used to control working condition of the inverter. The system simulation model was established in MATLAB/SIMULINK environment, and ran this simulation model.The simulation results show that: This system is feasible, and adaptive fuzzy PI control system has better dynamic and static characteristics than traditional PI control method.

Abstract: Motors of Independent Drive Electric Vehicle can be controlled independently, which can enrich the method of stability control for vehicle. In order to fully take use of the advantage，The man-vehicle system with eight degrees of freedom ,which includes Magic Formula tire model and driver model based on Preview Follower Theory, was set up by using MATLAB/SIMULINK. Considering the complexity of the driving condition and the nonlinear time-varying characteristics of the vehicle system, a Sliding mode controller based on transient reference model was set up, which selected Yaw rate as Control variable and two motors as actuators. The simulation results show that handling and stability of vehicle can be improved greatly by the Sliding mode controller.

Abstract: In the rotor field oriented vector control system, the use of permanent magnet synchronous motor voltage equations and flux equations derived PMSM position and speed estimation method has its unique advantages, The advantage of this approach is to calculate a simple, fast dynamic response, and easy to implement. However, when permanent magnet synchronous motor running at low speed, back EMF would be very small, which can not guarantee the accuracy of estimates. In addition, the position and speed estimation parameters of permanent magnet synchronous motor is largely in dependence on the running status of permanent magnet synchronous motor ,and vulnerable to temperature and magnetic saturation phenomena.All of these elements will lead to error increase. In order to solve the problem of inaccuracy in parameters estimation of motors at low speed, PI controller is introduced to obtain the rotor speed information, and then make up for deficiencies in the estimation algorithm. At the same time, this method can be applied to achieve smooth switching of high speed switching of the motor.

Abstract: In order to solve the complex thrust allocation problems of dynamic positioning ship with azimuth thrusters, thrust allocation and management system was built. The power optimal thrust allocation was formulated as a quadratic programming problem by the linear treatments of inequality constraints and the optimal solution could be found in a finite amount of time. And some influence factors of thrust allocation were separated from algorithms and treated as a superstratum management module. Using this system, online adjustment of input constraints and singularity avoidance can be realized, and the reliability and adaptability of thrust allocation are improved consequently. Finally, the validity and excellent performance of this method is proved by the simulations.

Abstract: Dynamic equations of an axisymmetric moving mass actuated reentry vehicle, which was in the state of tri-channel stability, were derived in this paper, and the linear dynamic equations in longitudinal plane were obtained. Then variable structure control method was applied to control the moving mass actuated reentry vehicle. The simulation results indicate that the controller is of satisfactory performances in the nonlinear system.