301 research outputs found
Event-Triggered Algorithms for Leader-Follower Consensus of Networked Euler-Lagrange Agents
This paper proposes three different distributed event-triggered control
algorithms to achieve leader-follower consensus for a network of Euler-Lagrange
agents. We firstly propose two model-independent algorithms for a subclass of
Euler-Lagrange agents without the vector of gravitational potential forces. By
model-independent, we mean that each agent can execute its algorithm with no
knowledge of the agent self-dynamics. A variable-gain algorithm is employed
when the sensing graph is undirected; algorithm parameters are selected in a
fully distributed manner with much greater flexibility compared to all previous
work concerning event-triggered consensus problems. When the sensing graph is
directed, a constant-gain algorithm is employed. The control gains must be
centrally designed to exceed several lower bounding inequalities which require
limited knowledge of bounds on the matrices describing the agent dynamics,
bounds on network topology information and bounds on the initial conditions.
When the Euler-Lagrange agents have dynamics which include the vector of
gravitational potential forces, an adaptive algorithm is proposed which
requires more information about the agent dynamics but can estimate uncertain
agent parameters.
For each algorithm, a trigger function is proposed to govern the event update
times. At each event, the controller is updated, which ensures that the control
input is piecewise constant and saves energy resources. We analyse each
controllers and trigger function and exclude Zeno behaviour. Extensive
simulations show 1) the advantages of our proposed trigger function as compared
to those in existing literature, and 2) the effectiveness of our proposed
controllers.Comment: Extended manuscript of journal submission, containing omitted proofs
and simulation
Certifying non-existence of undesired locally stable equilibria in formation shape control problems
A fundamental control problem for autonomous vehicle formations is formation
shape control, in which the agents must maintain a prescribed formation shape
using only information measured or communicated from neighboring agents. While
a large and growing literature has recently emerged on distance-based formation
shape control, global stability properties remain a significant open problem.
Even in four-agent formations, the basic question of whether or not there can
exist locally stable incorrect equilibrium shapes remains open. This paper
shows how this question can be answered for any size formation in principle
using semidefinite programming techniques for semialgebraic problems, involving
solutions sets of polynomial equations, inequations, and inequalities.Comment: 6 pages; to appear in the 2013 IEEE Multiconference on Systems and
Contro
Rigid formation construction from non-rigid components
This paper discusses the construction of rigid formation from arbitrary non-rigid components in two-dimensional space. Specifically, we focus on developing strategies for the construction sequences under the premise of building minimum number of links between the non-rigid components. Three operations, namely spindle splitting, rigid component shrink and edge floating, are proposed. The scenarios of acquiring a rigid formation from different kinds of non-rigid components are discussed respectively. It is proved that our strategy will guarantee the rigidity of the obtained formation with minimum number of inserted links, and will cover all the possible solutions during the construction process
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