Controller and disturbance observer design for robot manipulator to determine the applied force at the end-effector

This paper presents a nonlinear disturbance observer (NLDOB) designed for n-link robotic manipulators, specifically for three-degree-of-freedom manipulators in master-slave teleoperated surgical systems. The observer detects external forces applied to the end-effector of the slave robot, providing precise force feedback to the surgeon’s hand on the master robot. A dynamic model for n-link manipulators was developed, and stability was analyzed using the direct Lyapunov method. Numerical simulations on a three-joint robotic manipulator demonstrated high tracking accuracy under varying loads and external disturbances. The results show that the proposed observer maintains force estimation errors within ±0.1, ±0.2, and ±0.3 Newtons in the X, Y, and Z directions, respectively. This work contributes to enhanced force sensing and disturbance rejection in robotic surgical systems, offering a practical solution for real-time force feedback during minimally invasive surgeries.

Controller and disturbance observer design for robot manipulator to determine the applied force at the end-effector Keywords:

Nonlinear disturbance observer , Robotic manipulators , Teleoperated surgical robots , Force estimation