Research On Bioreactor Control System Based On Fuzzy Self-tuning PID Algorithm

The bioreactor cell culture technique is a general technique for culturing cells in suspension in a reactor,and is widely used in the biomedical field.The temperature,p H,and dissolved oxygen concentration(DO)of the culture medium in the cell culture process are critical for cell growth and reproduction.The three parameters are non-linear changes in the control process,and also has the characteristics of inertia,time-varying and hysteresis.Control effect is difficult to satisfactory.According to customer requirements,the need to control the temperature at 36.8 ℃± 0.4 ℃,PH value control between 7.2-7.4,dissolved oxygen concentration(DO)control at 97 ± 2%,the system response to faster,better stability.Therefore,this subject takes the temperature parameter of the bioreactor control system as the typical research object,and designs an effective control method,so that the adjustment time,overshoot quantity and stability of the system control temperature parameters are optimized.Firstly,the fuzzy control algorithm is researched deeply,and the whole process of cell culture is studied in detail.The main factors restricting cell growth are analyzed.Then the typical application of conventional PID control in industrial control is analyzed.A practical control algorithm is designed to lay a foundation for better control of the target parameters and improve the quality of cell culture.The lower part of the system is mainly composed of controller and culture tank.The controller uses Siemens S7-200 series PLC.The part of the culture tank is made of Omron G3 PE single-phase solid-state sensor.The BURKERT company is suitable for liquid medium Of the two-way solenoid valve,WOTSON-MARLOW company’s vaccine production of peristaltic pumps and other devices;host computer is used in Siemens Bote diagram V13 industrial control configuration software to achieve real-time control of the control parameters and the entire system operation real-time monitoring.The entire equipment selection cost-effective,system stability.In the algorithm part of the control parameter,the fuzzy self-tuning PID algorithm which can make the system control more stable and precise is researched by combining the fuzzy logic control with the conventional PID control.The algorithm can also realize on-line self-tuning of the controlled parameters.After simulating the controlled parameters on Simulink,it can be seen by comparing the curves of conventional PID control,single fuzzy control and fuzzy self-tuning PID control simulation.The new integrated control method will control the system And the adjustment time is reduced from 650 s to 400 s and 38.5%.The overshoot decreases from 32% to 25%,and the system steady-state error decreases to near zero.