Locomotion analysis of a clamper-based capsule robot in a compliant tube

A clamper-based capsule robot (CCR) capable of exploring a compliant tube is promising for a minimally invasive medical application. It is composed of a locomotion unit and some functional modules (e.g., camera and telemetry circuit) at both ends; and the locomotion unit consists of a linear mechanism, a fixed clamper, and a free clamper that can be linearly moved by the linear mechanism. For the CCR design and optimization, analyzing the interaction between the CCR and the compliant tube is necessary. For this reason, this article conducts a quantitative locomotion analysis of the CCR in the compliant tube. Based on a minimum displacement assumption and by analyzing the tube deformation induced by each CCR locomotion gait, a model correlating the CCR locomotion efficiency with it design parameters was built. Then, the correctness of the model was validated in an intestine-constructed compliant tube. With the validated model, the influence of the design parameters on the CCR locomotion efficiency was analyzed to derive the design rules. In addition, a quantitative comparison between the locomotion efficiencies of the CCR and a previously developed inchworm-like capsule robot was conducted, showing that the CCR can enable a more efficient exploration for the compliant tube.