Bilateral Energy Transfer for high fidelity Haptic Telemanipulation

Among the methods to grant the stability of a telemanipulation system, the bilateral time domain passivity framework has the appealing characteristic to consider both the forces and velocities signal exchanged between the master and slave systems, and the power introduced or dissipated by the elements that compose the whole telemanipulation system. In previous works, [2,7], has been shown how the bilateral passivity controller (BiPC) can preserve stability when the communication channel that conveys data between master and slave is affected by delay. In this work the authors intend to further explore the possibilities offered by the Bilateral Energy Transfer concept as design guideline, and refine the control schemes already discussed in [7]. The underlying idea of Bilateral energy transfer is to achieve a transport of energy between the two sides of the real system as similar to an “ideal” (not delayed) system as it is allowed by the energy leaks. As energy leak is intended the behavior introduced by the not ideality of some components, such as the communication channel. In the meantime, in order to obtain easy-to-use system, the control system must preserve, in some extend, the force, velocity, and position correspondences between master and slave. In order to achieve this goal, a modified version of passivity controller is presented. The main characteristic of this controller is that its correction action aimed to dissipate energy, regarded as generated by energy leaks, is limited and deferred in time. Moreover, in this paper is introduced a drift compensator which role is to match the master and slave position; in order to maintaining the whole system passivity, the action of this controller is bounded to the amount of energy that has been dissipated in excess by the BiPC.