Evaluation of Force Estimation Method Based on Sliding Perturbation Observer for Dual-arm Robot System

Dual-arm robots require information on the end-effector’s assembly force for the precision and accuracy of assembly work to be ensured. However, the attachment of a force sensor to the end-effector not only considerably increases cost and weight but also introduces structural problems. In this study, through simulations and experiments, a sliding perturbation observer is applied to a seven-degree-of-freedom robot arm to estimate the assembly force without the use of a force sensor. This paper proposes a method for determining whether the end-effector of a robot arm collides with an assembly part on the basis of the estimated perturbation without a force sensor. If the absolute values of the axes perturbations sharply increase, then it can be assumed that the end-effector of the robot manipulator and the assembly part have collided. This research also evaluates the extent of similarity between the estimated perturbation and reaction force at the moment of assembly.