In the previous chapter, we introduced tactile sensors as an additional source of information that enables a manipulation robot to identify the grasped object. To recognize the object, the robot acquired
tactile images after grasping was complete. In contrast to this, we focus in this chapter on features that describe the
in the tactile response while the robot is grasping or manipulating an object. As we will show, the dynamic components of the tactile signal can be used to infer several aspects of the internal state of an object. For example, these features allow a robot to detect whether a grasped bottle contains liquid and whether its cap has been properly closed. This information is highly relevant for domestic robots that fulfill service tasks such as tidying up.