5 research outputs found
Monitoring Control Updating Period In Fast Gradient Based NMPC
In this paper, a method is proposed for on-line monitoring of the control
updating period in fast-gradient-based Model Predictive Control (MPC) schemes.
Such schemes are currently under intense investigation as a way to accommodate
for real-time requirements when dealing with systems showing fast dynamics. The
method needs cheap computations that use the algorithm on-line behavior in
order to recover the optimal updating period in terms of cost function
decrease. A simple example of constrained triple integrator is used to
illustrate the proposed method and to assess its efficiency.Comment: 6 pages, 8 Figure
On Adaptive Measurement Inclusion Rate In Real-Time Moving-Horizon Observers
This paper investigates a self adaptation mechanism regarding the rate with
which new measurements have to be incorporated in Moving-Horizon state
estimation algorithms. This investigation can be viewed as the dual of the one
proposed by the author in the context of real-time model predictive control. An
illustrative example is provided in order to assess the relevance of the
proposed updating rule.Comment: 6 pages. 4 Figure
A Parametric Non-Convex Decomposition Algorithm for Real-Time and Distributed NMPC
A novel decomposition scheme to solve parametric non-convex programs as they
arise in Nonlinear Model Predictive Control (NMPC) is presented. It consists of
a fixed number of alternating proximal gradient steps and a dual update per
time step. Hence, the proposed approach is attractive in a real-time
distributed context. Assuming that the Nonlinear Program (NLP) is
semi-algebraic and that its critical points are strongly regular, contraction
of the sequence of primal-dual iterates is proven, implying stability of the
sub-optimality error, under some mild assumptions. Moreover, it is shown that
the performance of the optimality-tracking scheme can be enhanced via a
continuation technique. The efficacy of the proposed decomposition method is
demonstrated by solving a centralised NMPC problem to control a DC motor and a
distributed NMPC program for collaborative tracking of unicycles, both within a
real-time framework. Furthermore, an analysis of the sub-optimality error as a
function of the sampling period is proposed given a fixed computational power.Comment: 16 pages, 9 figure