Nikhil Chopra

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In this paper we study the problem of exponential synchronization for one of the most popular models of coupled phase oscillators, the Kuramoto model. We consider the special case of finite oscillators with distinct, bounded natural frequencies. Our first result derives a lower bound on the coupling gain which is necessary for the onset of synchronization.(More)
Challenges Communications: Real‐time control over networks with random time‐varying delay, communication loss, hybrid (discrete/continuous) dynamics, parameter uncertainty. Performance Goals: Position Tracking : The slave robot should track the position of the master. Force Reflection : To be immersed in the remote environment, the human should accurately(More)
This paper addresses the problem of time-varying communication delay in force reflecting bilateral teleoperation. The problem is motivated by the increasing use of the Internet as a communication medium where the time delay is variable depending on factors such as congestion, bandwidth, or distance. The well-known scattering formalism introduced in [1](More)
Bilateral teleoperators, designed within the passivity framework using concepts of scattering and two-port network theory, provide robust stability against constant delay in the network and velocity tracking, but cannot guarantee position tracking in general. In this paper we fundamentally extend the passivity-based architecture to guarantee state(More)
In this paper, we investigate issues in the discrete-time implementation of passivity based control of bilateral teleoperators. The usual scattering formalism which, in continuous time, guarantees passivity for any constant delay, is extended in several important ways to the discrete domain, in particular to the case where communication between the master(More)
Synchronization is a key concept to the understanding of self-organization phenomena occurring in coupled oscillators of the dissipative type. In this paper we study one of the most representative models of coupled phase oscillators, the Kuramoto model. The traditional Kuramoto model (all-toall connectivity) is said to synchronize if the angular frequencies(More)
This paper addresses the problem of steady-state position and force tracking in bilateral teleoperation. Passivity-based control schemes for bilateral teleoperation provide robust stability against network delays in the feedback loop and velocity tracking, but do not guarantee steady-state position and force tracking in general. Position drift due to data(More)
In this paper we propose a systematic methodology for designing implicitly verified event-triggered dynamic output feedback controllers for LTI systems that are observable and controllable. Event-triggering conditions that depend only on local information are proposed for sampled-data implementation of the observer and the controller in three different(More)
This paper addresses the problem of time-varying communication delay in force reflecting bilateral teleoperation. The problem is motivated by the increasing use of the Internet as a communication medium where the time delay varies depending on factors such as congestion, bandwidth, or distance. The well-known scattering formalism introduced in (Anderson and(More)
Passivity-based control has emerged as an important paradigm for synchronization of networked robotic systems. Despite the practical utility of task-space algorithms, the previous results focused on joint-space synchronization and were primarily derived for kinematically identical manipulators. Hence, in this paper, the problem of task-space synchronization(More)