Manipulation And Formation Of Multi-Point Based On Ultrasonic Standing Wave

The methods of multi-point manipulation include optical manipulation,acoustic manipulation,and magnetic manipulation.They are called optical tweezers,acoustic tweezers,and magnetic tweezers,respectively.They are playing an increasingly important role in interdisciplinary,biomedical,and chemical fields.In recent years,the research on acoustic tweezers has made continuous progress.Ultrasonic array control and standing wave control is main research direction.However,in terms of multi-point levitation,the array type suspension has too long iteration time for the objective function of multiple particle acoustic field focusing,which may have problems such as no solution during the solution process.The large array size has certain limitations for multipoint control.The standing wave phased array levitation produces a stronger particle acoustic field capturing force.The number of transducers used for the same amount of particle suspension is relatively small,and it is better in multi-point manipulation,so it has a wider range of applications and greater research potential.Therefore,this paper uses an ultrasonic standing wave phased array to study the control of multi-point.In order to establish an ultrasonic standing wave phased array radiation model,this paper starts from the principle of standing wave and combines a single ultrasonic transducer model to calculate the acoustic pressure distribution of the standing wave sound field model.The acoustic radiation force distribution is obtained in different axial directions.Then three main phased array models were created,which are concave model,circular model and plane model.After the model was established,we used Acoustic SIM to simulate the acoustic field.In the simulation,we obtained the distribution data of the acoustic radiation force,acoustic pressure,Cor’kov potential energy,etc.Then different indicators are analyzed.In circular model,the influence of the shape is explored.In concave model,the influence of the radius of curvature on the acoustic field is mainly explored.In plane array,the main factors have the number of arrays,the height of the array,and so on.We compare the advantages and shortcoming of the three phased array models in 10 aspects,such as levitation pressure,acoustic nodes,and acoustic traps,and decide to choose a plane array.In this paper,we apply a movement algorithm based on the BFGS.For the control of multi-point formations,the IB algorithm is more suitable.The algorithm calculates multiple acoustic traps at different positions through different phase combinations.The location and number of traps can achieve a simple formation.Both only need to control the phase array.In addition,this paper has carried out experimental verification on theoretical simulation.The experimental platform is based on the FPGA software and the phased array hardware of the double-layer phase array.In the experiment,we separately verified the simulation part,including the levitation stability,the analysis of the fault tolerance of the array randomly closed,and the phase array switching and moving experiments.Finally,different formations are formed through the changes of the acoustic traps.The experiment shows that phase array conforms to the simulation theory analysis in terms of the formation of the acoustic trap and the acoustic field distribution.