Transfer function modeling and dynamic performance analysis of single-axis acoustic-levitation systems

•A transfer function model to reveal the internal relationship between the position change of acoustic traps and the motion of levitated objects is proposed.•The time-domain dynamic performance and frequency-domain characteristics of levitated objects are systematically described.•The effects of parameter modulations on the time-domain dynamic performance and frequency-domain characteristics of the system are obtained.•Verification by simulations and experiments. The development of contactless acoustic-levitation technology has grown rapidly in recent years, and the acoustic-levitation system is an electromechanical system with complex dynamics. However, the traditional differential equation model, used as the core basement for the system, is ineffective at describing the effects of structural changes or parameter adjustments on system performance, which is vital for the design and analysis of the system. This paper proposes a transfer function model to solve this issue. The model can characterize the dynamic performance of the system. Meanwhile, it is competent to describe the effects of structural changes or parameter adjustments on system performance because it can directly derive the relationship between the system performance index and the system parameter variation. It simplifies system design and analysis. In the proposed model, the displacement of the acoustic trap and that of the object are considered as the input and output, respectively, clearly demonstrating the relationship between the acoustic-trap movement and the object motion. Based on the model, the time-domain dynamic performance and the frequency-domain characteristics of the system are systematically described. Furthermore, the model describes the effects of the parameters (the stiffness coefficient, levitated objects, and media) adjustments on the time-domain dynamic performance (damped oscillation frequency, rise time, and peak time) and the frequency-domain characteristics (resonance frequency and bandwidth frequency) of the system. The damping oscillation frequency, resonance frequency, and bandwidth frequency are positively correlated with the stiffness coefficient, while the rise time and peak time are negatively correlated with the stiffness coefficient. These results are verified by numerical simulations and physical experiments. These works will support the design of the acoustic-levitation controller, serve the analysis of the whole system performance, and guide the parameter