| Objective:For the past few years,as the development of science and technology,The technology of animal cell culture has been widely used in biomedical products in industrial production,such as the development of protein drugs,stem cell transplantation,vaccine production,artificial organs and other fields.For example,hematopoietic stem cell transplantation can be long-term reconstruction of hematopoiesis and immunity,it is suitable for the treatment of hematopoietic stem cells,progenitor cells and defective genes related to diseases,such as leukemia,severe immunodeficiency and autoimmune disease,is a kind of important biological treatment or cell therapy.However,the human body itself can provide little hematopoietic stem cells,which is an urgent need for large-scale expansion of these stem cells in vitro.The appearance of bioreactor provides a very effective method for the expansion in vitro of hematopoietic stem cells.The process of cell culture and proliferation is an extremely complex biochemical reaction process.There must be in a properly surrounding environment that the metabolism can be effectively.There has been a relatively mature bioreactor in foreign countries,but there is no commercialized animal cell bioreactor in china.This paper study on the control system of the wave bioreactor to complete a set of control system of cell culture conditions based on wave bioreactor,which can get better application in cell culture,and promote China's bioreactor industry forward.Methods:By analyzing and discussing the control methods and control systems of the current bioreactor,we propose a control method for the wave bioreactor culture system.The control system consists of three-part design: the design of the culture condition controling means,the design of software and hardware part of the control system,the simulation and the experimental verification.The design of control method,according to the requirement of temperature control and temperature control characteristics of large delay,we designed the control algorithm of Fuzzy-PID;In the light of the requirements of PH control and the strong nonlinearity of PH process,the segmented variable gain PID was improved to design four section variable gain PID control algorithm;According to the characteristics of non fixed value control of dissolved oxygen,design a control algorithm of PID+TP.With regard to the design of software part and hardware part of the control system,we use the Microprogrammed Control Unit as the core control chip,combined with MPLAB,MATLAB,etc..The effect of the control algorithms and the performance of the control system are verified by the actural experiments based on the simulation experiments.Content:The major work of this paper consists of following parts:?1?Research on the classification and parameter control method of bioreactor control system and the design of control system.Through a large number of literature review and contact with the relevant industry,study the latest progress of cell culture bioreactor.In this paper,we analyzed the advantages and shortcomings of various control methods and systems,so as to provide practical significance and application prospects for the selection and control methods of the control system.Design the whole system control plan and the best system scheme is selected by comparing the performance of hardware components and applications.?2?Hardware design and application of the control system.The design of hardware in system consists mainly of the selection of the execution unit of the lower computer,the selection of the host controller chip of the host computer and the integration between the host and lower computer.The hardware part of the slave computer is composed of a main control chip,a detection device,an actuating device and a transmission line.We choose the main control chip dspic30f6014 a microcontroller as the core of control system,which integrated the core processing layer and the peripheral circuit layer as input / output port,memory,timer,counter and so on are all integrated on a chip,it achieves things include receiving a whole set of experimental data,the computing,memory and transfer capabilitys;The detection device were selected for PT100 online,PH online instrument and dissolved o xygen meter according to the three culture conditions of the temperature,PH,dissolved oxygen concentration that need to be controlled;The executing device select electric blanket,peristaltic pump,electromagnetic valve etc..according to the control pri nciple.The host computer control unit choose the DGUS screen according to the need which set display,control,storage and other functions at a suit,to achieve the overall monitoring of the control system.The host and lower computer integration is mainl y realized by the communication lines between them and the unified communication protocol.?3?Designing and achieving the control algorithms of the control system.This paper mainly completed the design of the three kinds of control algorithms,namely the Fuzzy-PID temperature control algorithm,the four variable gain PID control algorithm for PH control and the TP-PID control algorithm for dissolved oxygen concentration.Among them,the Fuzzy-PID control algorithm is not used in the traditional parallel mode,it integrates the two methods together and it uses the detection signal as the input of fuzzy control,and the fuzzy-control's output as the input of PID control,finally the PID output result as the signal of output control of the control system;The four section variable gain PID control algorithm is improved based on segmented variable gain PID according to the actual situation of bioreactor,considering the strong nonlinear characteristics of PH control;The control algorithm of dissolved oxygen concentration is mainly refer to the traditional control mode considering that it only need to be controlled in a certain range.?4?The design of human-computer interface and the completion of touch configuration.The host computer man-machine interface uses the DGUS screen,the type is DWT80600T08006WT,which uses Microsoft Visio Premium 2010 to drawing,the display pictures includes system initialization,main interface,data input interface etc..Touch configuration using the DGUS V49 configuration tool,import the image into configuration tool,add text display,key return and the display of RTC configuration in the corresponding location area according to the operation requirements,and set up the corresponding configuration variables address,the length of text,the key value,the effect of the case etc..Then ipmort the image of the touch function into the DGUS screen to complete the design of human-computer interface.?5?The simulation experiments and practical experiments to verify the reliability of the algorithms and the performance of the whole control system.To verify the reliability of the control,simulation experiments include temperature control of Fuzzy-PID and PH control of segmented variable gain PID are designed with the Simulink software package in MATLAB,the control time and control precision can be used as the basis to judge whether the performance of the algorithm is reliable.Designe actural experiments after the verification of the reliability of the algorithm by simulation experiments.MPLAB software is used to design the programs of three control algorithms according to the design of algorithms,and then it is introduced into the Microprogrammed Control Unit to carry out the actual experiment.Walidation criteria is still control time and control precision after the stablilty.Results:This paper designed three control algorithms about the three culture conditions of temperature,PH and dissolved oxygen in wave bioreactor control system,the hardware selection of control system according to the requirement of cell culture,Completed the hardware choose of the control system,the circuit design,the design of the communication of host and lower computer,the selection and design of man-machine interface,and the program Microprogrammed Control Unit,finally,designed actual experimentals to verify the reliability of algorithms based on simulation experiments.Published two papers.Conclusion:This paper introduced all kinds of bioreactor control systems and control methods,by analyzing the advantages and disadvantages of all the control systems,we proposed the microcontroller as the main control chip of the wave bioreactor control system to study,and designed different control methods according to the characteristics of the cultivation conditions need to be regulated.When the actual experiments were carried out,the temperature control precision can reach ?0.1,the control precision of PH can reach ? 0.05,and the dissolved oxygen concentration control precision can reach ? 6%.The research shows that the control system can be operated stablly and reliably and the control effect is well,it also shows that the whole control system can well maintain the suitable environment that cell growth needed to meet the control requirement of cell culture process.The innovation of this paper is according to the different controlled conditions to design the corresponding control methods,such as Fuzzy PID control is designed for temperature control,The segmented variable gain PID is designed for the control of the PH;Use the dsPIC30f6014 a Type MCU as the main control chip,not only reduces the cost,but also improves the flexibility of the system,and shorten the development cycle;Use the DGUS screen as a man-machine interface,realize the collocation of interface;the system is modular designed,and integrated finally,reduce the impact rate of the failure. |
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