Applied Mechanics and Materials Vol. 740

Abstract: In order to achieve higher precision, reliability and stability, lower cost and power consumption, friendly user interface and network functions, loss-in-weight weighing Controller based on ARM9 and Windows CE is designed for controlling dynamic real time batching equipment. This paper first introduces the working principle and architecture of the embedded Controller, then explains hardware system component and design of software system of the Controller, developed on Platform Builder 5.0. The paper pays more attention on the application layer development. Subfuctions of application software are introduced and working flow chart of main modules is given. Double incremental PID algorithm used by the system is presented to achieve the highest accuracy in the shortest possible time. The high precision 0.1% can be achieved, and Controller products are widely used in the metallurgy, chemical industry.

Abstract: According to the time-varying and nonlinear characteristics of fluid, this paper puts forward a design scheme of real-time and accurate control of the liquid flow. The control system which taking the programmable logic controller (PLC) as the platform and using the PID control algorithm is composed with the touch screen, electromagnetic flow meter, temperature sensor, electric regulating valve system and so on. And the PID algorithm based on PLC design has carried on the analysis, simulation and optimization. The results show that PID algorithm is designed using this method with a strong and more precise control of the scheme. It is not only suitable for the flow control, changes in action after the equipment is also applicable to analog volume control temperature, liquid level, velocity, height etc.

Abstract: As to a 6-DOF wire-driven parallel manipulator in the application of virtual flight experiment of wind tunnel, the high precision motion control of supported aircraft model has been researched. First, the integrated dynamic model of the system has been established, and a proportional and differential controller has been designed on the base of position feedback. Finally, the numerical simulation of motion control system has been done in the example of 6-DOF motion. The analysis result shows that the high precision motion control can be achieved by PD control law for aircraft model, and the system stability could be improved by selecting wire tension coefficient properly, which can provide theoretical reference and support for virtual flight experiment of complex model and has great practical application value.

Abstract: In this paper, a simplified CNC system based on PLC and position controller is introduced. The position controller FX2N-20GM, is a pulse chain output unit, which can control motors to accomplish linear interpolation and circular interpolation. PLC,with the mode of FX_2N-16MR, the logic control unit of system, reads position data from the position controller and determines the operation of the system. Labwindows/CVI,the configuration software on PC, is the upper monitoring system, showing the motors position in real time by monitoring PLC. The system, combined PLC , position controller and configuration software, can draw any kinds of two dimensional graphics and show the trajectory of motors on PC in real time, the linear interpolation and circular interpolation had been perfectly implemented by a series of experiments. Compared with classic CNC system, it did not contain tedious hardware wring or complex software programming, which makes the whole structure a simplified CNC system.

Abstract: In view of the appearance of instability and malfunction problem for level control system in the steam drum of boiler, a new method to use statistical process control (SPC) was proposed, which analyzed the level data by the SPC. It can extract the main features of the level variable, and set up the upper and lower monitoring limits for the level control system in the steam drum of boiler. The decision-making basis for the operator can be provided by monitoring control accuracy of the level control system. With this method, it can improve the control accuracy of the level variable and provide the information quickly and efficiently for the fault diagnosis of the level control system, prevent the malfunction occurs, ensure safety and stable operation for the boiler control system.

Abstract: This paper presents a method for smart house electricity load control. The method, combined with TOU price and Real-time pricing, arranges various appliances and meets daily household electricity demand at the same time, so that to reduce the daily electricity consumption and realize Demand Response. First, this paper attempts to summarize problem witch need to be solved for realizing load control in a smart house. Second, the smart house load control problem was described as high-dimensional complex functions unconstrained optimization model and solved with Particle Swarm Optimization. Finally, design experiments used the method for a smart house. Experimental results show that the method can arrange various appliances and reduce electricity consumption.

Abstract: As the improvement of environmental protection requirements, the application of Hazard-free household disposal system becomes more widely. This paper expounded the applications of Siemens S7-300 in systems, described both the characteristics of Siemens software redundancy and its design and implementation in system in detail. The system has been successfully put into production and it operates stably in Linyi.

Abstract: In this paper, a new sliding-mode observer (SMO) for sensorless control of permanent magnet synchronous motor (PMSM) is proposed. The observer is built based on the study of the back electromotive force (EMF) equivalent control. The new SMO, which substitues a hyperbolic tangent function for the signum function with a variable boundary layer, can reduce the chattering phenomenon. In order to overcome the time delay, we cancelled the low-pass filter and phase compensation module. In this way, not only the structure of the observer is simplified, but also the estimation precision is improved. The simulation results prove that the new SMO has a good dynamic performance and static quality.

Abstract: For the imprecise and cumbersome of the brushless DC motor simulation, a novel simulation method based on modular design has been proposed. The Simulation model contains a power supply circuit, a PMSM , and a control unit which uses speed and current double-loop control mode. The outer ring of the double-loop control is speed loop with a PI control, it can stable torque and anti-load disturbance, the inner ring is current loop, with hysteresis current control, plays stable current role. Simulation results showed that the simulation method is precise and runs faster.

Abstract: The ability of the generator unit response frequency change is the key issue of assessing primary frequency regulation. Meanwhile, the setting of speed regulating system parameter greatly affects primary frequency performance of generators. Therefore, this paper proposes a comprehensive evaluation system, which can comprehensively analyze and evaluate the ability of primary frequency regulation from various aspects. It combines speed regulating system parameter index with common evaluation index. In this part, the author puts forward a multi-objective assessment algorithm. Firstly, when generators experienced disturbances, collect the corresponding data of plant and system. Then the speed regulating system parameter is estimated by the actual accident of generator. Besides, the common evaluation index is calculated, including the contribution electric quantity, response time, delay time and the contribution ratio. Finally, the algorithm is applied to the actual hydro power units and thermal power units, and the results illustrate the feasibility and reliability of the algorithm.