Research On Powdery Materials Weighing Control Of Asphalt Mixing Plant

With the development of our society,transport becomes one of the key factor affecting economic growth's.The growing volume of traffic and the emergence of large,heavy vehicles call for higher and higher demands to highway.Owning the high level road is very important to develop and speed the economic development.However,the quality of asphalt pavement and the use of performance are closely related to performance of raw materials on asphlat mixture gradation,construction control and so on..But the control of production mixing ratio is also an important factor.In addition to the structure of mixing plant,the more important impact of asphalt mixture ratio of production is the control of weighing accuracy.Therefore,the study on powdery materials weighing system for asphalt mixing equipment is an important issue which has the actual meaning of the project.This paper studied the basic structure and working principle of powdery materials weighing system for asphalt mixing equipment.It putted forward "two speed" way to powdery materials weighing system,which divided the weighing system to high-speed and low-speed process,This not only guarantee the weighing accuracy,but also the weighing speed.Because the weighing system as a transient non-linear system,it was equivalent to second-order system;then,we transformed the issue into a question of dynamic weighing.Through the estimated of factors affecting weighing,we obtained the specific control model of weighing system.This paper studied the problem of asphalt mixing equipment and the control model of weighing system,then,it putted forward the adaptive algorithms to control the whole weighing process.It divided the control process to two piriod.according realistic controlling value to revise the next controlling value,it can reduce the error constantly.Because weighing system has the feature of lagging,instability and overshoot, we design and apply smith predictor which improved the stability of weighing system.Meanwhile,using SIEMENS S7-300 programming language LAD completed the relevant programming,including data acquisition and processing module program,using simulation software S7-PLCSIM to debug the program to perform its normal functiom.In order to enhance anti-interference capacity of weighing system,designing the low pass filter and filtering program from aspects of hardware and software.The powdery materials weighing system of asphalt mixing is highly automated,high-efficiency,improving precision weighing characteristics.such as SIEMENS S7-300 controller used as a data acquisition and processing of the core equipment,to achieve automatic control of high-accuracy,advanced hardware and software used to improve the reliability of system,to achieve stability,low failure rate and bringing immeasurable economic benefits.