National Natural Science Foundation of China (No. 61503370), National Science and technology support program (2015BAI01B13) and the Natural Science Foundation of Liaoning Province (No. 20141151).
One of the most important reasons that make the capsule robot cannot be used in clinic is the absence of its mechanical model, especially when the capsule robot moves at a constant velocity, which is its major working condition. An analytical friction model of the capsule robot in the small intestine is researched in the paper. The model is based on the size of the capsule robot, hyperelastic constitutive model of the small intestine’s material and their interaction properties. Analytical expressions of time-dependent frictional resistance are obtained and curves are plotted when all the parameters are substituted. Compared with experimental results, the model calculation results are valid. The errors of the period, valley value and peak value are 6.88, 9.38 and 4.78 %, respectively. The work is hoped to perfect the friction model between the capsule robot and the small intestine and contribute to the development of the capsule robot.