Applied Mechanics and Materials Vols. 397-400

Abstract: In this paper, we propose a novel controller based on contractive model predictive control for the path following problem of a mobile robot. Besides dealing with path following, we also fulfill the following objectives: bounded control signals and optimal forward velocity. These three objectives are all achieved through integrating into our model predictive control framework as constraints. However, the major concern in the use of model predictive control is whether such an open-loop control scheme can guarantee system stability. In this case, we apply the idea of a contractive constraint to guarantee the stability of our MPC framework. To illustrate its effectiveness, several simulation scenarios have been conducted.

Abstract: This paper applied model free control method to the refrigeration system evaporator minimum stable superheat control. Compared with conventional PID control, model free control method has fast convergence, anti-interference ability. Meanwhile, model free control can reduce the coupling effect between evaporator superheat and evaporating temperature and be well adapted to the variable load control requirements of the refrigeration system, which has good steady state performance and dynamic performance.

Abstract: In order to reduce the wear of pantograph and catenary, prolong working time of the friction pair, and ensure the quality of current collection, a new type of pantograph active control strategy is designed. The strategy is based on the theory of friction and wears with electric current, control theory and micro-control technology, and is characterized by the dynamic wear test of catenary and the contact force control. The results show that the wear of the pantograph and catenary can be significantly reduced, the contact force fluctuation also can be effectively controlled, and the quality of the current collection of pantograph-catenary can be improved, while the active control strategy is applied.

Abstract: As the backup systems of RPS (reactor protection system), Diverse Actuation System and ATWS( Anticipated transients without scram) mitigation system are diversely designed from RPS system so as to offer protection for the normal operation of nuclear power plant. Both of the systems bear the function of mitigating the anticipated transients without scram events. Being isolated from RPS system, the design of DAS and ATWS system meeting the requirement of diversity and influences of CCFs (common cause failure) are effectively prevented. This article mainly analyzed the structure and function of the two systems and the similarities and differences between them.

Abstract: This paper designs the core structure of fuzzy parameters self-tuning PID controller on the basic of nonlinear tracking-differentiator. Through constantly testing error E and rate of change EC, makes the controlled object have good dynamic and static performance. In order to meet the different requirements of controller parameters in the different constant of E and EC, the system can modify three parameters online in operation, and realizes the comprehensive and simulation process based on VHDL.

Abstract: To enhance the current regulation capability for PMSM when transient state, which caused by the existence of numerical delay such as current sampling and Pulse-Width Modulation (PWM) duty-cycle updating, this paper proposed a predictive current control algorithm for permanent magnet synchronous motor which based on deadbeat control. The numerical delays in conventional FOC system are eliminated in theory. Simulation and experiment results show that the PMSM (Permanent Magnet Synchronous Motor) current predictive control scheme improves both the dynamic performance and steady-state precision of the PMSM control system.

Abstract: Control strategy of permanent magnet synchronous generator (PMSG) in variable speed wind power system has been design in this paper. The decoupling control can be realized by PWM converter with the field oriented strategy, and a novel adjusted method is discussed with excitation component compensation. Power characters and model of wind turbine are studied, and the simple maximum power point tracking (MPPT) algorithm is executed. Moreover, the complete control strategy is expressed considering the model limit of PMSG. The design adopted can feasible realize the predominant control within the permissible wind speed. The analysis and investigation results all have been confirmed that the excellent dynamic states and steady states performances of the control strategy.

Abstract: In order to test the performance of the two-wire flowmeter, the detection system based on virtual instrument technology is designed in this paper. This system mainly consists of four parts: master control unit, flow rate signal measurement unite, standard instrument and Measured instrument.The master control unit of the detection system is PC. With the communication protocol of MODBUS, PC control the detection device to synchronous sample the standard flow meter and the measured flow meter, and output 4 ~ 20mA current signal. The test analysis software is developed in LabWindows/CVI programming environment to achieve the test data automatically generated. Practice has proved that the system operation is simple, fast, and efficiency.

Abstract: A set of mechanical braking system matching and development method for hybrid vehicles is established with the reference of mechanical braking system development method for traditional vehicles. The control strategy and development method, which based on braking force distribution between front and rear axle, enable the recycle of energy as well as good brake efficiency. Finally, the development methods, which based on brake efficiency and braking regulations, has been analyzed and verified through parameter model.

Abstract: In order to obtain stable and high quality image from high-speed camera in real time under different environment, the system hardware based on TMS320DM642 is designed and a complex control method is proposed to realize auto-light control rapidly by harmonizing alterable diaphragm and camera exposure time. The algorithm of the auto-light system mainly consists of two parts: the analysis of brightness information based on Variance weighted information entropy, camera exposure time control and alterable diaphragm control based on data analysis. The project results show that the algorithm has rapid convergence and strong adaptability, and the system can realize large-scale and real-time auto-light at different conditions.