Study On Predictive Zone Control And Its Application In Pipeline Detector

Most of the control systems in industrial production adopt the set point value control mode,that is,the output of the control system is maintained at a certain point value.However,considering the complexity and variety of the production environment,the set point control cannot meet the control requirements very well in many cases.For example,when considering factors such as productivity,energy consumption and system controllability,the system output only needs to be controlled within a certain zone;in addition,when the model parameters of the control system are not accurate,it is very difficult to control the output variables at a set point value.Zone control means that giving the desired output target in form of "zone".The output variables can be controlled at any point in the zone.And the controller takes the corresponding action only when the output variables violate the zone.Compairing with set point control,zone control relaxed the control effect according to the control demand,which can make up for the defects of the control system freedom,reduce the frequency of control and improve the economic benefit.The speed control system of the pipeline detector is a typical zone control system.The safety of long-distance pipeline transportation of natural gas is an important issue which is related to national economy and people's livelihood.Regular detection of pipelines by using inner detection technology is an important way to ensure normal operation of pipelines,and the smooth running speed of inner detector is the premise for ensuring the quality of detection.In engineering,it is often required that the speed of the detector in the pipeline be controlled within a desired zone,so it's needed to use zone control method to control the speed of the Pipeline detector.In addition,the model of inner detector is quite complicated,the parameters of the model will change within a definite zone,so the model of speed control system of the inner detector is a kind of zone system,which belong to uncertain system.At present,there is little information on the speed control of the inner detector,and the control effect is not satisfactory.In this paper,the detector speed control system is taken as the research object,the zone control method is applied to the deterministic parameter model and the uncertain parameter model of the internal detector respectively.The specific research work is as follows:Firstly,the zone control is reviewed,including the research background and significance,the research status of zone control theory,and a brief introduction to the control of the detector speed in the pipeline.Secondly,for the determination system,considering the shortcomings of the conventional soft constrained zone control method,a method of soft constrained model predictive control with additional margin is proposed.By introducing the output margin,the zone error is effectively reduced.Finally,the stability analysis is given.Then,for uncertain systems,a zone predictive control method is proposed based on interval analysis.And the stability of the proposed algorithm is analyzed.Finally,the internal relations of four kinds of control systems are analyzed,and the universality of the methods proposed in this chapter is proved.Finally,through the analysis of the motion state of the inner detector,the deterministic parameter model and the uncertain parameter model of the inner detector are obtained.The control methods of the above determination system and the uncertain system are applied to control the inner detector respectively.Compared with the traditional methods,the superiority of the proposed algorithm is verified.In the end,the thesis made a whole summary and presented the future prospect on zone control further study.