Transparent bilateral teleoperation interacting with unknown remote surfaces with a force/velocity observer design

Abstract

ABSTRACTA master–slave teleoperation system is considered, in which the slave manipulator is interacting with a rigid surface with unknown geometry. It is assumed that neither force nor velocity measurements at the slave side are available. To deal with this problem, an extended-state high-gain observer is proposed to estimate in an arbitrary close manner the velocity and force signals. At the same time, the gradient vector for the remote surface is online estimated and employed into an hybrid position/force controller based on the orthogonal decomposition of the task space. A formal proof is presented, which guarantees ultimate boundedness of the state of the system, with arbitrarily small ultimate bound. Furthermore, it is established the transparency of the teleoperation system that, roughly speaking, gives the human operator the sensation of being interacting directly with the remote surface. The proposed scheme is validated through numerical simulations and experiments.