This paper proposes a model-mediated telemanipulation scheme, focusing on the kinaesthetic perception of specific geometric properties of the remote environment in the presence of time delay. The basic idea is inspired from previous work on impedance-reflection teleoperation, which is here extended to incorporate the construction of a two-dimensional local geometric model. This model incorporates the local curvature of the remote environment, estimated online using a recursive least squares (RLS) method, which is then used to reconstruct a virtual surface model at the master site for haptic display. A series of experiments has been conducted, where each subject manipulated the haptic master to kinaes-thetically explore the surface of a remote (virtual) environment. The analysis of the obtained experimental results, in terms of telehaptic discrimination of curvature, shows the effectiveness of the proposed model-mediated scheme at mitigating some of the adverse effects of time delay in the communication loop.

In present days, teleoperation is used in many challenging applications where the tasks to be accomplished from a distance are very complex and require accurate and reliable reproduction of the haptic sensations involved. The main factor that can cause a certain degradation of the quality of teleoperation is the presence of time delays. An effective way of alleviating the consequences of time-delays is the use of an adaptive impedance reflection teleoperation scheme, aiming to reconstruct at the master site a local model of the impedance of the remote environment. The goal of this paper is to show the effectiveness of such a controller via experiments that involve a real remote environment. In these experiments, a forced-choice procedure has been used, where each subject is presented in every trial with two spring fields (remotely located and telehaptically perceived) and is asked to identify the stiffer. The proposed adaptive teleoperation control scheme is compared to a typical direct force-reflection telemanipulation, in the presence of an emulated time delay of 100 msec. Experimental results show the superior performance of the proposed adaptive impedance reflection scheme, which, as opposed to classical direct teleoperation, seems to maintain the thresholds of human haptic perception close to the ones obtained when no time delay is present in the bilateral communication and control loop.

This paper proposes the application of an adaptive impedance control scheme to alleviate some of the problems associated with the presence of time delays in a haptic teleoperation system. Continuous on-line estimation of the remote environment's impedance is performed, and is then used as a local model for haptic display control. Lyapunov stability of the proposed impedance adaptation law is demonstrated. A series of experiments is performed to evaluate the performance of this teleoperation control scheme. Two performance measures are defined to assess transparency and stability of the teleoperator. Simulation results show the superior performance of the proposed adaptive scheme, with respect to direct teleoperation, particularly in terms of increasing the stability margin and of significantly ameliorating transparency in the presence of large time delays. Experimental results, using a phantom omni as the haptic master device, support this conclusion.

With the spread of low-cost haptic devices, haptic interfaces appear in many areas in the field of robotics. Recently, haptic devices have been used in the field of mobile robot teleoperation, where mobile robots operate in unknown and dangerous environments performing particular tasks. Haptic feedback is shown to improve operator perception of the environment without, however, improving exploration time. In this paper, we present a haptic interface that is used to teleoperate a mobile robot in exploring polygonal environments. The proposed visuo-haptic interface is found to improve navigation time and operator perception of the remote environment. The human-operator can simultaneously select two different commands, the first one being set as "active" motion command, while the second one is set as a "guarded" motion type of navigation command. The user can feel a haptic equivalent for both types of teleguidance motion commands, and can also observe in real-time the sequential creation of the remote environment map. Comparative evaluation experiments show that the proposed system makes the task of remote navigation of unknown environments easier