Tactile actuator technology

Over time, a wide variety of tactile stimulation devices have been designed and implemented in an attempt to minimize power requirements and weight while simultaneously maximizing the stimulus effect. Consequently, the hardware is widely varied and has specific strengths and weaknesses. This section discusses the basic features universal to particular tactile actuator (tactor) designs and a summary table indicating the key performance characteristics of each technology. In addition, there are several characteristics that must be considered when attempting to optimize the tactile actuator design. When considering the signal itself, it is important to take into account its strength/amplitude, the amplitude range, power consumption, and the frequency range. Ideally, the available frequency range and stimulus amplitude range should match that of the human sensory system (see Chapter 2) and its perceptual characteristics (see Chapter 3). Conversely, the power consumption should be kept to a minimum, especially when there is a need for portability. In addition, it is ideal to reduce the size/weight of the individual tactors, physical discomfort, distortion of the signal, and any sensitivity to contact pressure. Likewise, there is a need to maximize the reliability of the hardware, improve its ruggedness, and provide the option to protect electrical components from water. Lastly, the amount of acoustic energy and electromagnetic radiation should be kept to a minimum. However, it should be noted that some of these design requirements are specific to the type of tactor technology. For example, purely electrical stimulation typically does not yield acoustic energy radiation. These aspects are discussed in greater detail in the following sections