Estimation of Obstacle Contact Force and Position for Robots in Task Space

This paper presents a disturbance observer for robots that can estimate obstacle contact force and position in relation to the environment. The disturbance observer operates in task space, eliminating the need to measure accelerations. The global exponential convergence of the estimated disturbances to the true values was proven based on Lyapunov's theory. An experiment using a tree-pruning robot which has the possibility of colliding with tree branches is presented to show the effectiveness of the proposed disturbance observer.