nonlinear control of bilateral teleoperators interacting non-passive termination forces

In this paper, an interconnection and damping assignment passivity based controller is developed for nonlinear bilateral teleoperation system. the aim is to track the position and force in the teleoperation system in the presence of nonpassive external interactions and asymmetric variable timedelay in the communication channel.  for this end, a nonlinear control law is designed based on the notion of timedelay porthamiltonian systems for unforced teleoperator and the lyapunovkrasovskii theorem . sufficient synthesis conditions are derived in terms of linear matrix inequalities to tune the parameters of controller. then, by lyapunov redesign scheme, an auxiliary controller is developed to assure the stable position tracking in the presence of nonpassive operator and/or environment. the main contribution of the proposed method is that the stability and position tracking of system is attained via a fixedstructure controller in the presence of nonpassive interaction forces without need to their dynamical models and force sensor. since the proposed design conditions include the upper bounds of the varying timedelays and their rates; they are less conservative than some rival methods in literature. finally, transparency of the proposed scheme is proved. simulation results on a 2 degree of freedom teleoperation system are compared to rival methods to demonstrate the merits of the proposed strategy.