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Set-based and Dynamical Feedback-augmented Hands-off Control

Andrei Sperilă, Sorin Olaru, Stéphane Drobot

TL;DR

This work reframes hands-off control from a purely time-minimization perspective to a set-based, spatial approach for FD LTI systems. It introduces a hands-off region in the state space and uses dynamical feedback to keep the system's state inside this region, switching off control whenever possible. A joint, S-procedure–based synthesis procedure designs both a dynamical controller and lifted invariant sets that guarantee state and input constraints while enabling hands-off behavior with recursive feasibility and convergence guarantees. A numerical example with a discretized vehicle model demonstrates efficient, sub-millisecond computation and clear switching between open- and closed-loop modes, illustrating practicality and robustness of the approach. The results offer a principled, scalable path toward distributed or multi-agent implementations in contexts where centralized control is impractical.

Abstract

A novel set-theoretical approach to hands-off control is proposed, focusing on spatial arguments for command limitation rather than temporal ones. By employing dynamical feedback alongside invariant set-based constraints, actuation is employed only to drive the system's state within a "hands-off region" of its state-space, where the plant can freely evolve in open-loop configuration. A computationally-efficient procedure with strong theoretical guarantees is devised, and its effectiveness is showcased via an intuitive practical example.

Set-based and Dynamical Feedback-augmented Hands-off Control

TL;DR

This work reframes hands-off control from a purely time-minimization perspective to a set-based, spatial approach for FD LTI systems. It introduces a hands-off region in the state space and uses dynamical feedback to keep the system's state inside this region, switching off control whenever possible. A joint, S-procedure–based synthesis procedure designs both a dynamical controller and lifted invariant sets that guarantee state and input constraints while enabling hands-off behavior with recursive feasibility and convergence guarantees. A numerical example with a discretized vehicle model demonstrates efficient, sub-millisecond computation and clear switching between open- and closed-loop modes, illustrating practicality and robustness of the approach. The results offer a principled, scalable path toward distributed or multi-agent implementations in contexts where centralized control is impractical.

Abstract

A novel set-theoretical approach to hands-off control is proposed, focusing on spatial arguments for command limitation rather than temporal ones. By employing dynamical feedback alongside invariant set-based constraints, actuation is employed only to drive the system's state within a "hands-off region" of its state-space, where the plant can freely evolve in open-loop configuration. A computationally-efficient procedure with strong theoretical guarantees is devised, and its effectiveness is showcased via an intuitive practical example.

Paper Structure

This paper contains 9 sections, 4 theorems, 54 equations, 4 figures, 1 table, 2 algorithms.

Key Result

Theorem III.1

Consider a system of type eq:ss_sys and a controller of type eq:ss_ctl, for which $A_{CL}$ is a Schur matrix and for which $\Omega_I$ along with $\Omega_O$ satisfy I1)-I3) and O1)-O4), respectively. If the system's initialization satisfies $x[k_0]\in\mathcal{S}_c\,$, then applying Algorithm alg:ho_p

Figures (4)

  • Figure 1: The greyscale shading inside the sets indicates the connection between states and their corresponding control action: dark grey indicates admissible states that will never be reached (due to the applied commands), medium grey marks full "hands-on control" space, light grey designates the transitional space, and white is assigned to full "hands-off control" space.
  • Figure 2: The external acceleration profiles that act upon the vehicle.
  • Figure 3: State evolution of the vehicle, under the action of Algorithm \ref{['alg:ho_periodic']}.
  • Figure 4: The feedback actuation and switching computed by Algorithm \ref{['alg:ho_periodic']}.

Theorems & Definitions (13)

  • Remark II.1
  • Remark III.1
  • Theorem III.1
  • proof
  • Corollary III.1
  • proof
  • Remark III.2
  • Theorem III.2
  • proof
  • Theorem III.3
  • ...and 3 more