The integration of vibrotactile feedback in digital music instruments (DMIs) is thought to improve the instrument’s response and make it more suitable for expert musical interactions. However, given the extreme requirements of musical performances, there is a need for solutions allowing for independent control of frequency and amplitude over a wide frequency bandwidth (40–1000 Hz) and low harmonic distortion, so that flexible and high-quality vibrotactile feedback can be displayed. In this paper, we evaluate cost-effective and portable solutions that meet these requirements. We first measure the magnitude–frequency and harmonic distortion characteristics of two vibrotactile actuators, where the harmonic distortion is quantified in the form of total harmonic distortion (THD). The magnitude–frequency and THD characteristics in two unloaded cases (actuator suspended freely or placed on a sandbag) are observed to be largely identical, with minor attenuation for actuators placed on the sandbag. Loading the actuator (when placed in a DMI) brings resonant features to its magnitude–frequency characteristics, increasing the output THD and imposing a dampening effect. To equalize the system’s frequency response, an autoregressive method that automatically estimates minimum-phase filter parameters is introduced, which by design, remains stable upon inversion A practical use of this method is demonstrated by implementing vibrotactile feedback in the poly vinyl chloride chassis of an unfinished DMI, the t-Stick. We finally compare the result of equalization by performing sinesweep measurements on the implementation and discuss the degree of equalization achieved using it.

中文翻译：

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定义用于数字乐器的触觉工具包：表征音圈执行器，负载效应和频率响应均衡

震动触觉反馈集成在数字乐器（DMI）中被认为可以改善乐器的响应，使其更适合专家级的音乐互动。但是，鉴于音乐表演的极端要求，需要一种解决方案，以允许在较宽的频率带宽（40-1000 Hz）内独立控制频率和幅度，并实现低谐波失真，以便灵活，高质量的触感反馈被显示。在本文中，我们评估了满足这些要求的经济有效的便携式解决方案。我们首先测量两个振动触觉致动器的幅度-频率和谐波失真特性，其中谐波失真以总谐波失真（THD）的形式量化。在两个空载情况下（自由悬挂或放置在沙袋上的执行器），其幅值-频率和THD特性在很大程度上相同，而放置在沙袋上的执行器的衰减较小。加载执行器（当放置在DMI中时）会使其共振特性达到其幅度-频率特性，从而增加输出THD并产生阻尼效果。为了均衡系统的频率响应，引入了一种自动估计最小相位滤波器参数的自回归方法，该方法通过设计在反转时保持稳定。通过在未完成的聚氯乙烯底盘中实现触觉反馈，证明了该方法的实际应用DMI，对于放置在沙袋上的执行器，衰减很小。加载执行器（当放置在DMI中时）会使其共振特性达到其幅值-频率特性，从而增加输出THD并产生阻尼效果。为了均衡系统的频率响应，引入了一种自动估计最小相位滤波器参数的自回归方法，该方法通过设计在反转时保持稳定。通过在未完成的聚氯乙烯底盘中实现触觉反馈，证明了该方法的实际应用DMI，对于放置在沙袋上的执行器，衰减很小。加载执行器（当放置在DMI中时）会使其共振特性达到其幅值-频率特性，从而增加输出THD并产生阻尼效果。为了均衡系统的频率响应，引入了一种自动估计最小相位滤波器参数的自回归方法，该方法通过设计在反转时保持稳定。通过在未完成的聚氯乙烯底盘中实现触觉反馈，证明了该方法的实际应用DMI，t-Stick。最后，我们通过对实现进行正弦扫描测量来比较均衡的结果，并讨论使用它实现的均衡程度。