Tactile Displays for Virtual Reality Applications

本提案的目的是开发、构建和试验旨在刺激人体皮肤内的机械感受器的触觉显示器。显示器能够在正常方向以及横向方向上向指尖施加力和振动。为此，压电弯曲致动器与电磁驱动的法向力致动器组合成单个销。除了尺寸的销，个别致动器之间的相互作用进行了调查。如有必要，必须开发电子控制方案，以调整整个系统的各个致动器的性能。用于驱动该组合致动器的电子器件旨在实现可扩展性，因此由多个模块组成，包括主处理板和可变数量的信号发生器和运算放大器。由此产生的系统是特别紧凑的，可以自主操作，而不需要外部计算机。用于控制单个销的数据由基于有限元模拟的神经生理学激励模型生成。其目的是使用显示器为机械感受器创造足够的刺激，以尽可能接近原始触觉印象。该模型能够将真实的表面形貌转换为复杂的振动模式，以便在受体位置处紧密地再现最初发生的振动模式。一个中间表示称为“触觉地图”用于存储表面的抽象表示，并允许考虑粗糙以及精细的表面特征。基于我们新开发的4针触觉显示器，驱动电子设备的扩展和我们用于创建刺激的新创新模型，该概念需要扩展到4x4致动器阵列。除了创建用于寻址最终显示器的32个自由度中的每一个的导体路径之外，耦合的致动器的轴承可能需要优化。此外，驱动电子设备需要扩展。除了触觉显示器的位置之外，驱动电子设备还应该跟踪触觉显示器的方向。这样，用户手指的自然移动可以更准确地映射到模型。然后，需要通过一系列试验对组合系统的性能进行广泛评估。这些研究将与知觉心理学家合作进行。

Object of this proposal is the development, construction and the trial of a tactile display intended to stimulate the mechanoreceptors within the human skin. The display is able to exert forces and vibrations to the fingertip in normal as well as lateral direction. For this purpose a piezoelectrical bending actuator is combined with an electromagnetically driven normal force actuator into a single pin. Besides dimensioning of the pins, the interaction between individual actuators has to be investigated. If necessary, an electronically controlling scheme has to be developed in order to adjust the performance of the individual actuators of the whole system. The electronics for driving this combined actuators aims for expandability and therefore consists of several modules including a main processing board and a variable amount of signal generators and operational amplifiers. The resulting system is particularly compact and can be operated autonomously without the need for an external computer. The data for controlling the individual pins is generated by a neurophysiological motivated model based on Finite Element simulations. It aims to create adequate stimuli for the mechanoreceptors using the display to approximate the original tactile impression as close as possible. The model is able to transfer real surface topography to complex vibration patterns in order to recreate the originally occurring vibration patterns at the receptors position closely. An intermediate representation called "tactile map" is used to store an abstract representation of the surface and allows to take coarse as well as fine surface features into account. Based on our newly developed 4-pin tactile display, an extension of the driving electronics and our new innovative model for creating the stimuli, the concept needs to be extended to a 4x4 actuator array. Besides creating the conductor paths for addressing each of the 32 degrees of freedom of the final display, the bearing of the coupled actuator may need optimizations. Additionally, the driving electronics need to be extended. The driving electronics should also track the tactile display's orientation besides its position. This way, natural movement of the user's finger can be mapped to the model more accuratly. The performance of the combined system then needs to be evaluated extensively by a series of trials. These studies will be conducted in cooperation with a perceptual psychologist.