Novel shape-lockable self-propelling robot with a helical mechanism and tactile sensing for inspecting the large intestine

This paper presents a pneumatic colonoscopic robot with tactile sensing and shape-locking abilities. With the integration of a helical rotating propulsion module, a specially designed soft-sensing module, and a wire-tension-based shape-locking module, the proposed robot achieves excellent efficiency, visualization quality, and safety. The propulsion module can generate a helical rotating motion in tubular environments with good adaptivity to rigid, flexible, vertical, and elbow tubes. The sensing module, employing a specially designed soft sensor based on conductive rubber, can monitor the contact status between the robot and the environment to avoid slippage and reduce discomfort to patients. In conjunction with actuating balloons, the shape-locking module can keep the robot in any helical formation, which allows the camera attached to the robot to obtain a stable view. Experimental results show that the robot has great adaptability to tubes of different diameters (26–32 mm) and considerable propelling velocity (as fast as 20 mm s⁻¹ with 30 mm tube diameter). The feasibility and practicability of the sensing module and shape-locking module are also demonstrated. A screening test in a simulated colon tube validates its excellent comprehensive performance and indicates good potential for the proposed robot.