  This paper presents a novel design and experimental investigation for a
self-propelled capsule robot that can be used for painless colonoscopy during a
retrograde progression from the patient's rectum. The steerable robot is driven
forward and backward via its internal vibration and impact with orientation
control by using an electromagnetic actuator. The actuator contains four sets
of coils and a shaft made by permanent magnet. The shaft can be excited
linearly in a controllable and tilted angle, so guide the progression
orientation of the robot. Two control strategies are studied in this work and
compared via simulation and experiment. Extensive results are presented to
demonstrate the progression efficiency of the robot and its potential for
robotic colonoscopy.
