Behzad Khademian

Dual-User Teleoperation Systems: New Multilateral Shared Control Architecture and Kinesthetic Performance Measures

This paper proposes a novel six-channel multilateral shared control architecture for dual-user teleoperation systems. The proposed controller allows interaction between two users as well as the slave and environment through a dominance factor. The dominance factor adjusts the authority of the users over the slave robot and environment. The proposed controller is implemented on a haptic simulation test bed consisting of two planar twin pantograph haptic devices and a simulated pantograph as the slave robot. To analyze the kinesthetic performance of the proposed multilateral shared controller, a number of performance measures are extended or proposed. These measures are evaluated analytically and experimentally for various types of environments, users’ grasps, and levels of dominance of the users over the task.

Shared control architectures for haptic training: Performance and coupled stability analysis

A novel shared control architecture is presented for dual-user haptic training simulation systems for enhanced interaction between the users and between each user and the virtual environment. The coupled stability of the proposed control architecture against uncertainties in the environment and the user’s dynamics is investigated using the three-port master–slave network model of the dual-user haptic simulation system. For this purpose, Llewellyn’s unconditional stability criterion is applied to an equivalent two-port network model obtained from the corresponding three-port network, considering the environment as a load termination. The kinesthetic performance of the proposed architecture is numerically analyzed for transparency and evaluated against a benchmark control architecture under different operating conditions, such as various types of environments, users’ grasps, and levels of dominance of users over the task. An experimental user study is carried out to assess the effectiveness of the proposed architecture in terms of users’ perception of environment stiffness sensing, device agility, and haptic guidance reception.

A robust multilateral shared controller for dual-user teleoperation systems

This paper proposes a force-position multilateral shared control architecture for dual-user teleoperation systems that is robust stable to uncertainties in userspsila hand dynamics, environment impedance and userspsila dominance over the task. The proposed controller is evaluated for intermittent contact for different levels of dominance of the users over the task using dynamic simulations.

Unconditional stability analysis of dual-user teleoperation systems

A novel method is presented for unconditional stability analysis of dual-user teleoperation systems. The method is based on the application of Llewellyns criterion to an equivalent two-port network of the system. Unlike unconditional stability of single-user systems which depends on the multi-port network parameters, the unconditional stability of dual-user systems also depends on the network port termination, in this case the environment impedance. The proposed robust stability analysis method is examined on two multilateral shared control architectures previously developed in [11, 12].

A Framework for Unconditional Stability Analysis of Multimaster/Multislave Teleoperation Systems

A novel robust stability analysis framework is presented for unconditional stability analysis of multimaster/multislave teleoperation systems. Unlike the unconditional stability criterion for single-user systems, the newly proposed criteria for unconditional stability of multimaster/multislave teleoperation systems depend on the multiport network parameters and the port terminations. In addition to the analytical solution, the graphical demonstration of the unconditional stability region facilitates the analysis of coupled stability against variations in the dynamics of the environments and operators, even when they behave actively. The proposed robust stability analysis framework is examined on two multilateral shared control architectures that were previously developed for dual-user teleoperation systems.

Novel shared control architectures for enhanced users' interaction in haptic training simulation systems

This paper proposes two new multilateral shared control architectures for dual-user haptic training systems. Similar to the architecture previously proposed in [1], the controllers allow interaction between both users, the trainee and the trainer, as well as between the users and the virtual slave robot and environment. However, the newly proposed architectures provide increased maneuverability and enhanced sense of environment to the users. The kinesthetic performance of the proposed control architectures are analyzed under different operating conditions. Furthermore, the architectures are implemented on a dual-user haptic simulation testbed for user study experiments to investigate the effectiveness of the proposed architectures in terms of sense of environment, maneuverability, and guidance.

Experimental performance evaluation of a haptic training simulation system

In this paper the performance of a dual-user haptic simulation system with a proposed shared control architecture is experimentally evaluated for a specific trajectory following task under different operating conditions. The multilateral control architecture developed for training purposes, allows interaction between both users, the trainee and the trainer, as well as between the users and the virtual slave robot in a shared environment. The performance of the architecture is evaluated experimentally in terms of the effect of environment point of view, environment mushiness, and the existence of virtual fixtures. The performance is measured against task completion time, the path following accuracy and energy exchange by the trainer and the trainee.

Kinesthetic performance analysis of dual-user teleoperation systems

In dual-user teleoperation systems, unlike traditional teleoperation systems, two users are in interaction with each other as well as with environment. In this paper, the issue of transparency in such collaborative systems is discussed. In addition a number of measures are presented to analyze kinesthetic performance in dual-user systems. These indices are evaluated for a collaborative haptic control architecture presented in [1] for various types of environments, user grasps, and levels of dominance of users over tasks.