4,175 research outputs found
Transients of platoons with asymmetric and different Laplacians
We consider an asymmetric control of platoons of identical vehicles with
nearest-neighbor interaction. Recent results show that if the vehicle uses
different asymmetries for position and velocity errors, the platoon has a short
transient and low overshoots. In this paper we investigate the properties of
vehicles with friction. To achieve consensus, an integral part is added to the
controller, making the vehicle a third-order system. We show that the
parameters can be chosen so that the platoon behaves as a wave equation with
different wave velocities. Simulations suggest that our system has a better
performance than other nearest-neighbor scenarios. Moreover, an
optimization-based procedure is used to find the controller properties
Robust Distributed Control Protocols for Large Vehicular Platoons with Prescribed Transient and Steady State Performance
In this paper, we study the longitudinal control problem for a platoon of
vehicles with unknown nonlinear dynamics under both the predecessor-following
and the bidirectional control architectures. The proposed control protocols are
fully distributed in the sense that each vehicle utilizes feedback from its
relative position with respect to its preceding and following vehicles as well
as its own velocity, which can all be easily obtained by onboard sensors.
Moreover, no previous knowledge of model nonlinearities/disturbances is
incorporated in the control design, enhancing in that way the robustness of the
overall closed loop system against model imperfections. Additionally, certain
designer-specified performance functions determine the transient and
steady-state response, thus preventing connectivity breaks due to sensor
limitations as well as inter-vehicular collisions. Finally, extensive
simulation studies and a real-time experiment conducted with mobile robots
clarify the proposed control protocols and verify their effectiveness.Comment: IEEE Transactions on Control Systems Technology, accepte
Sensitivity Function Trade-offs for Networks with a String Topology
We present two sensitivity function trade-offs that apply to a class of
networks with a string topology. In particular we show that a lower bound on
the H-infinity norm and a Bode sensitivity relation hold for an entire family
of sensitivity functions associated with growing the network. The trade-offs we
identify are a direct consequence of growing the network, and can be used to
explain why poorly regulated low frequency behaviours emerge in long vehicle
platoons even when using dynamic feedback
Transients in the Synchronization of Oscillator Arrays
The purpose of this note is threefold. First we state a few conjectures that
allow us to rigorously derive a theory which is asymptotic in N (the number of
agents) that describes transients in large arrays of (identical) linear damped
harmonic oscillators in R with completely decentralized nearest neighbor
interaction. We then use the theory to establish that in a certain range of the
parameters transients grow linearly in the number of agents (and faster outside
that range). Finally, in the regime where this linear growth occurs we give the
constant of proportionality as a function of the signal velocities (see [3]) in
each of the two directions. As corollaries we show that symmetric interactions
are far from optimal and that all these results independent of (reasonable)
boundary conditions.Comment: 11 pages, 4 figure
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