Simulation And Experiment Research Of Particle’s Transportation Trajectory In Acoustic Standing Wave Field Based On Mixed-modulation Method

As a kind of non-contact manipulation technology, ultrasonic standing wave transportation using transducer array is able to transport any small particles. Meanwhile ultrasonic transportation doesn’t require any special physical properties of the sample. So this non-contact manipulation method show great advantage in the field of micro-assemble, biochemistry engineering, pharmaceutical chemistry, processing high property material. So it is important to improve the transportation process controllability, which is the key point to the advantag e of the ultrasonic transportation.Frist of all, this paper analyzes the mechanism of ultrasonic standing wave transportation and the transportation controlling methods of amplitude modulation and phase modulation, proposes the transportation method of am plitude/phase mixed-modulation. Then builds the parametric model of the transducer array. When the amplitude modulation is set as a sine function, this paper gets different potential well transfer trajectories under different phases. Based on the linearity of the transfer trajectories, the corresponding relations between the phases and the amplitude modulation function are figured out. With the amplitude/phase mixed-modulation control method, the linearity of the transfer trajectory is enhanced, and it becomes easier to control the particle’s position during transportation.Then, this paper researches suspended particle’s transportation trajectory. Firstly, the distribution of horizontal acoustic radiation force’s variation is researched, and builds a motion equation. According to this equation, the motion trajectories of a levitated particle under different modulation period are calculated iteratively. It is pointed that the relative distance between the particle location and the potential well position can’t be too long for stable transportation. Accordingly, the shortest modulation period for ultrasonic standing wave transportation is obtained.In addition, this paper analyses the transducer array controlling requirement, and has developed a high frequency power supply. This power supply outputs two voltage/phase mixed-modulating signals successfully. Meanwhile, the signals are switched automatically between the array elements.Finally, this paper establishes a experiment system of ultrasonic standing wave transportation using transducer array, and does the experiments as follows: Setting the voltage modulation function as sine function, does the transportation experiment at different phases. Based the transportation tractor, this paper figures out the corresponding relations between the phases and the voltage amplitude, which is the amplitude/phase mixed-modulation function. With the amplitude/phase mixed-modulation method, another transportation experiment is down. Then transport the particle at different modulation period, and the transportat ion tractory is analysed.