Browsing Waterloo Research by Author "Nielsen, Christopher"
Now showing items 119 of 19

Cardinality Constrained Robust Optimization Applied to a Class of Interval Observers
McCarthy, Philip James; Nielsen, Christopher; Smith, Stephen L. (IEEE, 20140721)We propose a linear programmingbased method of interval observer design for systems with uncertain but bounded model parameters and initial conditions. We assume that each uncertain parameter in the system model is bounded ... 
Coordinated path following of unicycles : A nested invariant sets approach
Doosthoseini, Alireza; Nielsen, Christopher (Elsevier, 2015)We formulate a coordinated path following problem for N unicycle mobile robots as an instance of a nested set stabilization problem. Stabilization of the first set corresponds to driving the unicycles to their assigned ... 
Dual Conditions for Local Transverse Feedback Linearization
D'Souza, Rollen S.; Nielsen, Christopher (IEEE, 20190121)Given a controlaffine system and a controlled invariant submanifold, the local transverse feedback linearization problem is to determine whether or not the system is locally feedback equivalent to a system whose dynamics ... 
Global SampledData Regulation of a Class of Fully Actuated Invariant Systems on Simply Connected Nilpotent Matrix Lie Groups
McCarthy, Philip James; Nielsen, Christopher (IEEE, 20210209)We examine a regulator problem for a class of fully actuated continuoustime invariant systems on Lie groups, using a discretetime controller with constant sampling period. We present a smooth discretetime control law ... 
Global Stability of a Class of Difference Equations on Solvable Lie Algebras
McCarthy, Philip James; Nielsen, Christopher (Springer, 20200617)Motivated by the ubiquitous sampleddata setup in applied control, we examine the stability of a class of difference equations that arises by sampling a right or leftinvariant flow on a solvable matrix Lie group. The map ... 
Hybrid Virtual Holonomic Constraints for a 2D.O.F. Bipedal Robot
Al Lawati, Mohamed; Nielsen, Christopher (IEEE, 20150625)We apply virtual holonomic constraints (VHCs) to a fully actuated EulerLagrange system with impacts : a bipedal walking robot consisting of a stance leg, swing leg and hip mass. We call these hybrid virtual holonomic ... 
Local nested transverse feedback linearization
Doosthoseini, Alireza; Nielsen, Christopher (Springer, 20150829)We study two local feedback equivalence problems for a nonlinear controlaffine system with two nested, controlledinvariant, embedded submanifolds in its state space. The first, less restrictive, result gives necessary ... 
Local observers on linear Lie groups with linear estimation error dynamics
Koldychev, Mikhail; Nielsen, Christopher (IEEE, 20140306)This technical note proposes local exponential observers for systems on linear Lie groups. We study two classes of systems. In the first class, the full state of the system evolves on a linear Lie group and is available ... 
A Local Solution to the Output Regulation Problem for SampledData Systems on Commutative Matrix Lie Groups
McCarthy, Philip James; Nielsen, Christopher (IEEE, 20180816)We present a smooth nonlinear control law for a kinematic plant on commutative matrix Lie groups that achieves regulation, if the state tracking and estimation errors are initialized in a suitable neighbourhood of identity. ... 
Local synchronization of sampleddata systems on oneparameter Lie subgroups
McCarthy, Philip James; Nielsen, Christopher (IEEE, 20170703)We present a distributed nonlinear control law for synchronization of identical agents on oneparameter Lie subgroups. If the agents are initialized sufficiently close to one another, then synchronization is achieved ... 
Local transverse feedback linearization for nested sets
Doosthoseini, Alireza; Nielsen, Christopher (IEEE, 20160211)We study a local feedback equivalence problem for a nonlinear controlaffine system with two nested, controlled invariant, embedded submanifolds in its state space. The main result of this paper gives necessary and sufficient ... 
Mitigation of CyberPhysical Attacks in MultiArea Automatic Generation Control
Alhalali, Safoan; Nielsen, Christopher; El Shatshat, Ramadan A. (Elsevier, 201911)In recent years, several cyberattacks have been recorded against sensitive monitoring systems. Among them is the automatic generation control (AGC) system, a fundamental control system used in all power networks. AGC ... 
PassivityBased Control of SampledData Systems on Lie Groups with Linear Outputs
McCarthy, Philip James; Nielsen, Christopher (Elsevier, 20161222)We present a method of stabilizing a sampleddata system that evolves on a matrix Lie group using passivity. The continuoustime plant is assumed passive with known storage function, and its passivity is preserved under ... 
Path Following for Mobile Manipulators
Gill, Rajan; Kulic, Dana; Nielsen, Christopher (Springer, 20170725)This paper presents a framework of path following via set stabilization for mobile manipulator systems. The mobile manipulator is modelled as a single redundant dynamic system. The mobile base considered belongs to a large ... 
Path following using dynamic transverse feedback linearization for carlike robots
Akhtar, Adeel; Nielsen, Christopher; Waslander, Steven L. (IEEE, 20150216)This paper presents an approach for designing path following controllers for the kinematic model of carlike mobile robots using transverse feedback linearization with dynamic extension. This approach is applicable to ... 
Periodic Adaptive Stabilization of Rapidly TimeVarying Linear Systems
Simard, Joel D.; Nielsen, Christopher; Miller, Daniel E. (Springer, 20190619)Adaptive control deals with systems that have unknown and/or timevarying parameters. Most techniques are proven for the case in which any time variation is slow, with results for systems with fast time variations limited ... 
PhaseLocked Loop Stability Based on Stochastic Bounds
Baker, Robert J. A.; Leung, Bosco; Nielsen, Christopher (Springer, 20150811)In this paper we study the stability of a phaselocked loop (PLL) in the presence of noise. We represent the noise as Brownian motion and model the circuit as a nonlinear stochastic differential equation, with the noise ... 
Synchronized closed path following for a differential drive and manipulator robot
Li, Yuqian; Nielsen, Christopher (IEEE, 20160523)We locally solve a synchronized pathfollowing problem for a heterogeneous multiagent system consisting of a differential drive robot and a serial manipulator. Each is assigned a simple, regular, and closed curve in its ... 
Transverse Feedback Linearization with Partial Information for SingleInput Systems
Nielsen, Christopher (SIAM, 20140925)This paper is motivated by the problem of asymptotically stabilizing invariant sets in the state space of control systems by means of output feedback. The sets considered are smooth embedded in submanifolds and the class ...