Research On Ultrasonic Phased Array Dynamic Suspension System Based On FPGA

With the development of modern ultrasonic technology,the acoustic suspension technology has gradually developed,and it has been widely used in the fields of biological reaction,droplet separation,and high temperature treatment.The traditional standing wave suspension has problems such as poor maneuverability and the need for a reflector to establish a standing wave sound field,which greatly limits its application.Ultrasonic phased array focusing suspension technology is a new type of acoustic suspension technology,which can control the suspension of objects in any position in three dimensions through phase modulation technology.It has the advantages of strong maneuverability and flexible sound beam,so the scope of ultrasonic phased array application is more and more extensive.In this paper,we will study the problem that the workpiece is difficult to reach a stable suspension state in the process of ultrasonic machining.A new ultrasonic suspension system,FPGA ultrasonic phased array suspension system,will be built.The control technology controls the array delay signal generation,and outputs the array ultrasonic signal to the open array semi-elliptical device to produce a focusing effect,which realizes energy gathering in space and can cancel out the gravity of the suspended matter,thereby realizing Suspension,the workpiece can be placed in a microgravity environment to achieve the steady state.The research content of this paper is as follows:(1)By studying the acoustic wave equation and the ultrasonic phased array focusing theory,the two-dimensional plane ultrasound focused sound field and the sound field time series color map are simulated.Combined with the fan array focusing theory,the open array model focusing method is derived.The numerical simulation method is used to simulate the sound field change of the open array in the non-suspended state and the suspended state.Simulating the same radius of polyethylene foam and water droplet suspension state gets the array ultrasonic sound field change trend map and axial sound pressure change trend map,which is to analyze the change of polyethylene foam and water droplet suspension sound field.(2)This paper mainly studies the hardware circuit system design and focus delay algorithm of open array.Firstly,an ultrasonic focusing delay transmission system is established to accurately control the delay signals of various parts to ensure the accuracy of the array ultrasonic emission focusing.Then,an ultrasonic power amplifying circuit is established,and the input delayed signal is subjected to signal amplification processing so that the output signal matches the power requirement of the ultrasonic suspension.Finally,through a single ultrasonic probe test,verify the amplitude of the output signal of the circuit and the signal delay of each part,and finally complete the design of the hardware circuit.(3)Based on the established open array suspension system,the array focused suspension performance was studied.Firstly,the test device and test method are introduced.Then,when the diameter of the polyethylene foam is different,when the input power circuit is the same as the diameter of the polyethylene foam,different power circuits are input,and the relationship between the suspension states is changed.It turns out that only when the polyethylene foam has a diameter of 1 mm and the voltage of 18-19 V is input,the polyethylene foam can be stably suspended in the open array sound field.