Li Suling

Application of PLC and Industrial Control Configuration Technique in Middle or Small Water Works

Giving an example of a small second pressing water works, the principle, construction and characteristics as well as the application of a automatic constant pressure closed-loop water supply and monitor system, composed of PLC and industrial control configuration software and frequency converter, is introduced in this paper. The system, which is tested in the applying scene, has the features of operating simple, moving reliable, automatic level high, protecting function completely and saving-energy better. It has the marked economic and social benefit as well as the value of spreading application also.

Maximum power point tracker for solar cells based on boost converter

In order to overcome the shortcomings such as long time and high cost of using solar cells to experiment, this paper successfully used a DC power supply and a variable resistor to simulate the solar cells output characteristic curve, its feasibility is analyzed theoretically. The basic principle of the maximum power point tracking (MPPT) was described in detail. Aiming at the normal maximum power point tracker algorithms some deficiencies in low tracking and concussion near the maximum power point, a new MPPT method—beeline approximation method combined with perturbation method with changing perturbation step is presented. Experimental results show that the system can track the maximum power point accurately and quickly, and the proposed method can eliminate the power oscillation at maximum power point.

Development on the Forming Principle and Control Model of Taper Leaf Spring

Taper leaf spring mill is the special equipment for rolling leaf springs used in automobiles. During the rolling technological process of taper leaf spring, in order to obtain the equal-stress mechanics characteristic of taper leaf spring it is need to control the dynamic changes of gap between rollers, completing the figure of parabola or other special ones along the longitudinal parabola of un-machined plates. Therefore, the type of two-degree computer controlling system is adopted in the controlling system of taper leaf spring mill, in which, the top one is industrial computer, the below one is PLC. Structure characteristics and composing principles based on the dynamic controlling system are researched, establishing the mathematics model of controlling system. The controlling program is developed based on the manufacturing craftwork flow of taper leaf spring. The equipment has been applied in the practical manufacturing, achieving kinds of equal-stress taper leaf spring provided with different parabola coefficients.

Design and Implementation of Electro-Hydraulic Control System of Multi-station Press

Multi-station press is an advanced special forming mechanical equipment. The Centralized control mode has been adopted by PLC in the machine. The control system software construction is the modular program type. The control program of PLC fulfills real-time controlling and testing in the system’s runtime. And there are various protection function devices and alarm devices on the press. Equipped with Electro-hydraulic servo-driven hydraulic cylinder and sensor with the properties of high precision and good linearity, many procedures calendar of vehicles leaf spring such as rolling, scrap edge, pressure tank, stamping and so on could has been completed on the machine by Using multi-stage feeding mechanism (manipulators) which delivers work-pieces from one mold to be shaped, then to another one to formed.

The stability analysis and improvement of SPIDNN control system

SPIDNN (Single-output Proportional Integral Derivative Neural Network) control is the dynamic integration of neural network with PID. PID neural network control system was only applied to the system which has PID prior knowledge. For improving and expanding its using range, the improved algorithm was proposed on the basis of analyzing of the structure, the algorithm and its stability based on the different applied condition. The improved algorithm includes the improvement of output function, adoption of the attachment momentum method, the dynamic change of the step length and the elimination of the static error. And carried on the simulation with Matlab to the improved algorithm, the result indicates that the improved algorithm has very good effect in the aspect of the speed of convergence. The validity of the algorithm has been verified experimentally. Therefore, no matter that having the PID prior knowledge or not, the improved PID neural network control system can realize the systematic stability.

Design and application of auto-constant water supply system

An automatic constant pressure closed-loop water supply and monitor system of small, Secondary Pressure Waterworks, which composed of Siemens S7–300 PLC, WinCC and ABB frequency converter, is presented. The principle and construction as well as characteristics of the system are introduced also. The function, the stability and the reliability of the water supply system has been improved. The super-harmonic oscillation and labour intensity of workers is reduced. The purpose of saving energy and reducing consumption has been realized. The necessary support conditions have been provided for the entire production management information system.

Development of Control System of Electro Hydraulics Servo Leaf Spring Mill

The electro hydraulics servo tape leaf spring mill is a special equipment used to manufacture automobile tape leaf spring. The structure of main body of mill is adopted four-column type. The roll gap of mill is driven by the servo hydraulics cylinder. The type of two degree computer control system, composed by microcomputer and PLC, has been adopted in this mill. The movement control requirement of the mill for manufacturing tape leaf spring has been analyzed. The structure characteristic and forming principle of the electro hydraulics servo control system of the mill has been introduced. The control programs for rolling leaf spring and digital PID had been designed for having accomplished the automatic control of roll gap for tape leaf spring and precision indemnity. The precision and efficiency requirement of all type of leaf spring at home and abroad to the mil has been satisfied.