arXiv subjects

Kunal Garg

Publications and source records attributed to Kunal Garg.

42 records · Page 3Linked to original sources

arXiv2019

Prescribed-time convergence with input constraints: A control Lyapunov function based approach

In this paper, we present a control framework for a general class of control-affine nonlinear systems under spatiotemporal and input constraints. Specifically, the proposed control architecture addresses the problem of reaching a given final set $S$ in a prescribed (user-defined) time with bounded control inputs. To this end, a time transformation technique is utilized to transform the system subject to temporal constraints into an equivalent form without temporal constraints. The transformation is defined so that asymptotic convergence in the transformed time scale results into prescribed-time convergence in the original time scale. To incorporate input constraints, we characterize a set of initial conditions $D_M$ such that starting from this set, the closed-loop trajectories reach the set $S$ within the prescribed time. We further show that starting from outside the set $D_M$, the system trajectories reach the set $D_M$ in a finite time that depends upon the initial conditions and the control input bounds. We use a novel parameter $μ$ in the controller, that controls the convergence-rate of the closed-loop trajectories and dictates the size of the set $D_M$. Finally, we present a numerical example to showcase the efficacy of our proposed method.

eess.SY↗

arXiv2018

First results on $\mathrm{K}^{*}(892)^{\pm}$ resonance production in pp collisions with ALICE at the LHC

The study of strange hadronic resonances in pp collisions contributes to the study of strangeness production in small systems. Measurements in pp collisions constitute a reference for the study in larger colliding systems and provide constraints for tuning QCD-inspired event generators. Since the lifetimes of short-lived resonances such as $\mathrm{K}^{*}(892)^{\pm}$ ($τ\sim 4$ fm/\textit{c}) are comparable with the lifetime of the fireball produced in heavy-ion collisions, regeneration and rescattering effects can modify the measured yield, especially at low transverse momentum. The first results for the $\mathrm{K}^{*}(892)^{\pm}$ resonance obtained in inelastic pp collisions at $\sqrt{\text{s}}=$ 5.02, 8, and 13 TeV will be shown. The $\mathrm{K}^{*}(892)^{\pm}$ has been measured at mid-rapidity via its hadronic decay channel $\mathrm{K}^{*}(892)^{\pm}\rightarrow \mathrm{K}^{0}_{\mathrm{S}}+π^{\pm}$, with the ALICE detector. In particular, the transverse momentum ($p_{\mathrm{T}}$) spectrum, integrated yields, $\langle p_{\mathrm{T}}\rangle$ and ratio to stable hadrons will be presented. The $\mathrm{K}^{*}(892)^{\pm}$ results are compared with $\mathrm{K}^{*}(892)^{0}$ measurements and with commonly-used Monte Carlo models. Measurements at 13 TeV are in addition a baseline for comparison with pp measurements at other LHC energies.

hep-ex↗

arXiv2018

Hybrid Planning and Control for Multiple Fixed-Wing Aircraft under Input Constraints

This paper presents a novel hybrid control protocol for de-conflicting multiple vehicles with constraints on control inputs. We consider turning rate and linear speed constraints to represent fixed-wing or car-like vehicles. A set of state-feedback controllers along with a state-dependent switching logic are synthesized in a hybrid system to generate collision-free trajectories that converge to the desired destinations of the vehicles. The switching law is designed so that the safety can be guaranteed while no Zeno behavior can occur. A novel temporary goal assignment technique is also designed to guarantee convergence. We analyze the individual modes for safety and the closed-loop hybrid system for convergence. The theoretical developments are demonstrated via simulation results.

eess.SY↗

arXiv2018

New Results on Finite-Time Stability: Geometric Conditions and Finite-Time Controllers

This paper presents novel controllers that yield finite-time stability for linear systems. We first present a sufficient condition for the origin of a scalar system to be finite-time stable. Then we present novel finite-time controllers based on vector fields and barrier functions to demonstrate the utility of this geometric condition. We also consider the general class of linear controllable systems, and present a continuous feedback control law to stabilize the system in finite time. Finally, we present simulation results for each of these cases, showing the efficacy of the designed control laws.

math.DS↗

arXiv2018

Finite-Time Resilient Formation Control with Bounded Inputs

In this paper we consider the problem of a multi-agent system achieving a formation in the presence of misbehaving or adversarial agents. We introduce a novel continuous time resilient controller to guarantee that normally behaving agents can converge to a formation with respect to a set of leaders. The controller employs a norm-based filtering mechanism, and unlike most prior algorithms, also incorporates input bounds. In addition, the controller is shown to guarantee convergence in finite time. A sufficient condition for the controller to guarantee convergence is shown to be a graph theoretical structure which we denote as Resilient Directed Acyclic Graph (RDAG). Further, we employ our filtering mechanism on a discrete time system which is shown to have exponential convergence. Our results are demonstrated through simulations.

eess.SY↗

arXiv2018

Robust Semi-Cooperative Multi-Agent Coordination in the Presence of Stochastic Disturbances

This paper presents a robust distributed coordination protocol that achieves generation of collision-free trajectories for multiple unicycle agents in the presence of stochastic uncertainties. We build upon our earlier work on semi-cooperative coordination and we redesign the coordination controllers so that the agents counteract a class of state (wind) disturbances and measurement noise. Safety and convergence is proved analytically, while simulation results demonstrate the efficacy of the proposed solution.

eess.SY↗