Non-singular Fast Terminal Sliding Mode Control for Crack Sealing Manipulator

In this work, the branch of the tree robot has been controlled for crack sealing of concrete pipe. This tree robot is used for repair and maintenance purposes. It can maneuvers inside vertical pipes, horizontal pipes and surfaces. A CAD model of the pipe is modelled in Solidworks, and a mimic of the existing crack is simulated inside the pipes. Furthermore, the crack repair has been assured for the branch of the tree robot. However, due to the presence of uncertainty and disturbances, the end-effector of the tree robot doesn't follow the desired crack trajectory. Sliding mode control (SMC) is a well-known method to address such types of problems. But, conventional SMC solved one aspect of the problem. Therefore, The Non-singular fast terminal sliding mode control (NFTSMC) is proposed for this work since it ensures fast convergence in finite time. After performing the simulation and numerous iterations, it is found that the NFTSMC gives a more promising result compared to SMC with constant plus proportional reaching law (CPPRL). Furthermore, the work exploits the Lyapunov candidate function to ensure the asymptotic stability of the crack trajectory.