Acoustic Soft Tactile (AST) skin is a novel soft-flexible, low-cost sensor that can measure static normal forces and their contact location. This letter presents the design, fabrication, and experimental evaluation of AST skin. The proposed AST skin has some Acoustic channels(s) (ACs) arranged in parallel below the sensing surface. A reference acoustic wave from a speaker unit propagates through these ACs. The deformation of ACs under the contact force modulates the acoustic waves, and the change in modulation recorded by a microphone is used to measure the force magnitude and the location of the action. We used a static force calibration method to validate the performance of the AST skin. Our two best AST configurations are capable of (i) making more than 93% of their force measurements within $\pm$ 1.5 N tolerances for a range of 0-30 N and (ii) predicting contact locations with more than 96% accuracy. Furthermore, we conducted a robotic pushing experiment with the AST skin and an off-the-shelf Xela uSkin sensor, which showed that the AST skin outperformed the Xela sensor in measuring the interaction forces. With further developments, the proposed AST skin has the potential to be used for various robotic tasks such as object grasping and manipulation.

翻译：声学柔性触觉（AST）皮肤是一种新型软柔性、低成本传感器，可测量静态法向力及其接触位置。本文介绍了AST皮肤的设计、制造和实验评估。所提出的AST皮肤在传感表面下方平行排列若干声学通道（ACs）。扬声器单元发出的参考声波通过这些ACs传播。接触力作用下ACs的形变调制了声波，麦克风记录的调制变化用于测量力的大小和作用位置。我们采用静态力标定方法验证了AST皮肤的性能。两种最佳AST配置能够：（i）在0-30 N范围内，超过93%的力测量误差在$\pm$ 1.5 N以内；（ii）接触位置预测准确率超过96%。此外，我们使用AST皮肤与商用Xela uSkin传感器进行了机器人推挤实验，结果表明AST皮肤在测量相互作用力方面优于Xela传感器。通过进一步开发，所提出的AST皮肤有望应用于物体抓取与操控等多种机器人任务。