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Byline: Abhijit. Chandra, Prabhu. Singh, Saket. Kumar, Nikhil. Chopra, Vishal. Gupta, Pradeep. Joshi, Vivek. Gupta Introduction: Laparoscopic ventral mesh rectopexy (LVMR) has gained widespread acceptance for the management of complete [...]

Byline: Nikhil. Chopra, Vivek. Gupta, Rahul, Saket. Kumar, Pradeep. Joshi, Vishal. Gupta, Abhijit. Chandra Introduction: Most centres offer laparoscopic treatment for liver hydatid cyst (LHC). There have been concerns about [...]

In this technical note 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. This bound improves the one derived by Jadbabaie et al. [8]. We then calculate a lower bound on the coupling gain that is sufficient to guarantee oscillator synchronization and derive further sufficient conditions to ensure exponential synchronization of the angular frequencies of all oscillators to the mean natural frequency of the group. We also characterize the coupling gain that is sufficient for the oscillator phase differences to approach any desired compact set in finite time. Index Terms--Cooperative control, exponential stabilization, Kuramoto oscillators, multi-agent systems, synchronization.

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 loss and offset of initial conditions is a well-known problem in such systems. In this paper, we introduce a new architecture, which builds upon the traditional passivity-based configuration by using additional position control on both the master and slave robots, to solve the steady-state position and force-tracking problem. Lyapunov stability methods are used to establish the range of the position control gains on the master and slave sides. Experimental results using a single-degree-of-freedom master/slave system are presented, showing the performance of the resulting system. Index Terms--Bilateral teleoperation, force tracking, position tracking, time delay.