Multichannel Ultrasound Focusing Delay Control Method Based on Variable-Length Shift Register for Airborne Ultrasound Tactile Feedback

Abstract

This paper presents a multichannel ultrasound focusing delay control method based on a variable-length shift register to solve the problem of using counters that occupy more resources. The proposed method can realize the delay control of the driving signal of each transducer of an ultrasound array and achieve ultrasound focusing. While collecting and storing the input data, the shift register moves the stored data to the right, and the delay control of driving signals of all the channels can start simultaneously by controlling the enabling time of the input signal of the shift register. Using experiments, it is verified that the error of the proposed method is related to the frequency of the delay control clock; the higher the frequency of the delay control clock is, the smaller the error and the diameter of the focal point are. The proposed method uses only one shift register to achieve ultrasound focusing without using additional hardware circuits and thus occupies fewer system resources. The proposed method can be applied in the human-computer interaction, virtual reality, and augmented reality fields. INDEX TERMS Multichannel delay control method, tactile displays, ultrasound focusing method.

Haptic Interface Device Using Cable Tension Based on Ultrasonic Phased Array

“…Initially, most of the studies about ultrasonic tactile feedback focus were on improving the physical rendering pressure by advancing hardware and developing rendering tactile patterns [14][15][16][17][18]. The intensity can be improved by utilizing standing waves [14] or enlarging the size of the ultrasonic array [15].…”

Peripheral focused ultrasound stimulation and its applications: From therapeutics to human–computer interaction

“…Large-scale arrays could expedite haptic feedback in wider interaction areas and more applicable scenarios (Suzuki et al, 2019). Moreover, delay control strategies are critical when simultaneously controlling hundreds or thousands of transducers (Chen et al, 2020). Indeed, due to acoustic transmission law, the airborne US can only work in homogeneous media, which might limit its applications in some special conditions.…”

“…Unlike diagnostic US imaging which employs relatively low-intensity US of 0.05-0.5 W/cm 2 (Chen et al, 2020), the intensity of FUS can vary widely. Both low-intensity and high-intensity US have been utilized through thermal effects or non-thermal effects.…”