Applied Mechanics and Materials Vols. 713-715

Abstract: In this paper, a cycle mean value engine model was built, and the ship propulsion system model was developed by combining the engine model with propeller and ship model following a modular approach in MATLAB/Simulink environment. In addition, the fuzzy PID control theory was investigated and applied in the ship speed intelligent control system under different disturbance circumstances with emphasis at slow steaming condition. Finally, the simulation results indicate that the fuzzy PID controller can improve the dynamic performance of the ship speed control system, decrease oscillation as well as increase response speed.

Abstract: The main drive system using for four-high mill is usually a double closed loop DC motor speed regulating system. Generally, the speed controller and current controller are PID controllers, and the parameters of controllers are determined by the engineering design method. Once disturbance occur, the control effects are often just passable. In this paper, fuzzy logic is used to set the parameters of the speed PID controller, so as to improve the disturbance rejection ability. Simulation results show that the fuzzy tuning PID controller can give better control effect than the regular control.

Abstract: This paper studied the novel 3-PRRR manipulator, the non-singularity workspace was deduced, satisfying various constrains, containing the angle scales of driving pairs, the travelling limits of driven pairs and the singular position conditions. Stepwise refinement method was employed and acceleration approaching method were put forward to improve the performance evaluation solving speed.

Abstract: The research of semi active suspension control strategy once was a hot point in the field of automobile suspension [2, 3], but it is difficult to achieve for most of them. I choose VI-CarRealTime to build vehicle model based on ADAMS vehicle model. Kalman Filter designed based on 1/2 vehicle model supply control signals for controller. Considering characteristics of CDC damper, Skyhook control strategy is applied for simulation, the simulation results show that, Skyhook Control can improve vehicle ride comfort in CDC damper control range.

Abstract: This paper sketches the overall structure of the hydraulic system of bending machine, and designs the hydraulic synchronous control system of the upper roller in bending machine. Then making use of AMEsim software to establish hydraulic system simulation model to analyze the pressure, velocity, displacement and other parameters of hydraulic cylinders in two cases when in open loop and closed loop system. After that, use PID algorithm to simulate the upper roller of bending machine in hydraulic closed loop synchronous system, which verifies that it can meet the motion requirements and get a higher synchronous precision.

Abstract: A flux damping control strategy was proposed to accelerate the decay of stator flux and restrain stator, rotor current and torque oscillation caused by grid voltage dips. Firstly, this paper analyzes the simplified mathematical model of DFIG during symmetrical voltage dips. Then, the mechanism of flux damping control strategy to restrain stator, rotor current oscillation and increase flux damping was analyzed. The flux damping control strategy can increase the damping of stator side, which accelerates the decay of the stator flux natural component and improve the dynamic LVRT performance of DFIG. The correctness and effectiveness of this method is verified by MATLAB/Simulink simulation results.

Abstract: We have analyzed some reliability problems of the 2UPS+UP mechanism using continuous Markov repairable model in our previous work. According to the check and repair of the robot is periodic, the discrete time Markov repairable model should be more appropriate. Firstly we built up the discrete time repairable model and got the one step transition probability matrix. Secondly solved the steady state equations and got the steady state availability of the mechanical leg, by the solution of the difference equations the reliability and the mean time to first failure were obtained. In the end we compared the reliability indexes with the continuous model.

Abstract: Through the analysis of molding process of large-scale plastic hollow containers, this paper carries on the simulation and optimization of hydraulic system, which focuses on the high energy consumption problem of large-scale blow molding machine. According to the characteristics of long work period and great fluctuation of flow demand, the paper designs the oil supplying system that can match the actuators’ hydraulic energy demand, introduces the working process of each component in the system, and analyzes the key technology of hydraulic system as well. The design and research avoids the shortcomings such as more components, complex debugging, discontinuous control and unstable operation, substantially reduces the installed capacity of variable pump and driving motor, and in the meantime, solves the impact problem of actuators effectively, which can make hydraulic system high efficiency, energy saving and run steadily.

Abstract: Because of some intrinsic properties of the PZT actuator, such as hysteresis, creep and nonlinearity effect, it’s difficult to achieve satisfactory results and control precision for conventional PID controller. In order to improve the control precision of the PZT driven of micro positioning platform, we proposed a CMAC neural network based on PID control scheme, which has the characteristics of realizing feed-forward control and obtaining the inverse dynamic model of controlled object by the CMAC neural network controller, and realizing feedback control by conventional controller, which can ensure the system stability and suppress disturbance. Form MATLAB simulation results, it demonstrates that the CMAC+PID control algorithm can be able to improve the control precision and response time of the system, and enhance the anti-interference ability and robustness, comparing with the traditional digit PID control algorithms.

Abstract: This project shows the simulation of a robotic modular system. It has one kind of module, which can couple with two more. The modules have five degrees of freedom (DOF), and can move in four different ways: independent module mode, caterpillar mode, snake mode and wheel mode. The last three kinds of movements need to have several modules coupled. Each module can move either using two pivots at its ends or by using tiny wheels that allow it to move in a direction that is perpendicular to the direction it follows when using its pivots; these gyratory elements also allow the module to rotate around one of its ends. The system controls based on sine functions.