Many robotic applications require a robot to operate in an environment with unknowns or uncertainty, at least initially, before it gathers enough information about the environment. In such a case, a robot must rely on sensing and perception to feel its way around. Moreover, it has to couple sensing/perception and motion synergistically in real time, such that perception guides motion, while motion enables better perception. In this talk, I will introduce our research in combining perception and motion of a robot to achieve autonomous contact-rich assembly, object recognition, object modeling, and constrained manipulation in uncertain or unknown environments, under force/torque, RGBD, or touch sensing. I will also introduce our recent work on integrated semantic SLAM and accurate loop closure detection, SmSLAM+LCD.