Robots are currently widely applied in lots of areas such as industry, agriculture, medicine, transportation, social service, military, space exploration, and undersea exploiting. The robot sensor, as a key component of the robot, has been paid increasing attention by robot researchers. Furthermore, sensor based human-robot interaction is currently the frontier of robot research. Robot sensing technology has been an evolving research field involving a strong interdisciplinary effort from researchers in different fields, namely, electronics, mechanics, material science, measurement and control, signal processing, bioengineering, and so forth. During the last decade, much effort has been done to develop robot sensors for robot control, robot perception, robot navigation, human-robot interaction, teleoperational robot, and so forth. In spite of the large and increasing interest and promising applications, robot sensor design is a significant challenge, which is involved in not only chemical sensors, biosensors, optical sensors, and physical sensors but also signal processing, data fusion, and pattern recognition. For instance, remarkable examples of tactile sensors and systems have been proposed; however, their capability to address specific applications and their extension to other fields such as medical instrumentation, prosthetic devices, and augmented reality are questionable.