Research On Phase Optimization Of Array Ultrasonic Microparticle Manipulation

With the rapid development of biological cell,material chemistry and precision electronics industries,the requirements for manipulating target objects are becoming higher.Acoustic manipulation is the non-contact control method which able to meet the requirements because its safety and non-damage to objects.However,the ultrasonic standing wave manipulation has poor flexibility and is only manipulated in one-dimensional space.And it requires cumbersome acoustic emission components,which limits the application in various fields.Starting from the acoustic field of the array,the study has established the ultrasonic manipulation model of the array and optimized the model.This study realized the three-dimensional spatial manipulation of particles,and analyzed the motion state of the manipulated object.Aiming at the problem of acoustic field and visualization of array ultrasonic transducer,the radiation model of single point acoustic source in space from the wave equation is deduced in this thesis.Then the radiation model of circular piston transducer is calculated based on the single point acoustic source.According to the spatial position of each transducer in the ultrasonic array and the superposition property of sound waves,the acoustic field model of the array transducer is obtained.Based on the radiation model of array transducer,the acoustic field of array transducer is visualized and simulated by MATLAB,and the acoustic field distribution characteristics of single transducer and array transducer are analyzed.Aiming at the array ultrasonic manipulation model and its solution problem,the mathematical model of particle manipulation in sound field is constructed from the point of sound energy of object.Genetic algorithm is proposed by a phase optimization solution,and the motion state of particles is analyzed by image measurement method.Starting from the mechanism of the object's manipulation in the sound field,the radiation force received by the object in the sound field is analyzed,and the manipulation model of particles in the array sound field is obtained.In order to obtain the phase solution of the model,BFGS algorithm is used to solve the model,and then genetic algorithm is introduced to solve the control model of large-scale array.The visual simulation of the phase results is carried out.Then the influence of model parameters and the position of the control points on the manipulate performance is analyzed.According to the acoustic pressure distribution of the manipulate field,an equivalent spring oscillator model is proposed to analyze the factors affecting the stability of the control particles.Simulation experiments show that compared with traditional methods,the results of large-scale array can be obtained quickly by using genetic algorithm,which is significance to the optimization of array ultrasonic manipulation model.Finally,a phase control system based on FPGA is designed in this thesis,and the capture and movement experiments of polypropylene pellets are carried out with hardware platforms which includes circuit,transducer array and camera.The experimental results show that the control model and its optimization method can manipulate particles stably.