| Electronic weighing technology is an integration of mechanism,electron,material, information and supervisation and is also a systemic project.Quantitative steelyard and other weighing apparatus get wide attention in the whole world as a newly high-tech industry.In various weighing apparatus,input value of static weighing is eternal,little interfered and these to the dynamic weighing are completely different.For dynamic weighing system,one side,signal form and disturbance which are produced by different weighed objects are various.On the other hand,the weighing process is time-variant, non-linearity and etc.So dynamic weighing's control is more complex and difficult than static weighing's control.The technology of dynamic weighing at home is not mature,and weighing control system is the hardcore of the electronic steelyard.Because of these,this paper adopts prognosticating method on-line to control the electronic steelyard's dynamic weighing process,and parallelly connects sensor to enhance the control system's precision, velocity,reliability and practicability for the steelyard's weighing control system.This paper analyzes the whole weighing control system and makes multilevel control to the weighing process according to the dynamic weighing's traits,for the purpose of assuring weighing velocity and precision.In the control method,this design establishes prognosticating model first and then estimates switch quotiety which is based on the prognosticating model in all levels to adjust on-off time of entering staff's valve.The control system's hardware and software of this design both adopt modulization makeup which is convienient for maintenance and diagnosis.Except for the study on control method,this paper also research on the following parts:signal's collection,magnifying, filtering,A/D conversion,data processing,liquid crystal display,serial communication and etc.In order to reach high precision,each component is filtrated rigorously.For the sake of heightening the system's reliability and stability,the paper introduces multi-methods to make the anti-jamming design for the hardware and software of the system.The drawing software used in this design is Protel 99SE,and we made imitate experiments before entitative experiments.In this way,the research cost is greatly reduced and the study period is shortened.According to the data from the experiments,we analyze the result,take apart the experiments' error in various aspects and ascertain the controller's whole design. |
