2026/7/29
Yazdan Batmani

Yazdan Batmani

Academic rank: Associate Professor
ORCID:
Education: PhD.
ResearchGate:
Faculty: Faculty of Engineering
ScholarId:
E-mail: y.batmani [at] uok.ac.ir
ScopusId: Link
Phone: 4345
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Research

Title
Suboptimal Safety-Critical Control of Nonlinear Systems With Time-Varying Constraints
Type
JournalPaper
Keywords
barrier states | nonlinear systems | optimal control | safety-critical control | SDRE | time-varying constraints
Year
2026
Journal International Journal of Robust and Nonlinear Control
DOI
Researchers Yazdan Batmani ، Mohammad Hosein Sabzalian

Abstract

This paper develops a suboptimal safety-critical control framework for nonlinear systems subject to time-varying constraints by integrating barrier-state augmentation with the state-dependent Riccati equation (SDRE) technique. First, a single-barrier design guarantees asymptotic stabilization and forward invariance of slowly evolving safe sets.Next, a multibarrier extension assigns each safety constraint its own barrier state and weighting factor, enabling independent tuning of conservativeness. At each time step, the controller solves a pointwise SDRE for the augmented dynamics. We establish that, provided the employed state-dependent coefficient (SDC) representation is pointwise controllable and observable, the origin of the closed-loop system remains asymptotically stable as long as the variation rates of the safety constraints are bounded. A key extension addresses scenarios where safety constraints and stabilization objectives are in conflict, ensuring forward invariance of time-varying safe sets even when the origin may belong to the unsafe set. To this end, we introduce a conflict-resolution barrier state and a discounted cost formulation that prioritizes safety over stability until constraints realign. Simulation results on mobile-robot collision avoidance and quadrotor navigation tasks show strict enforcement of time-varying constraints, successful handling of conflicts, and up to 50% faster computation than standard CBF-QP methods, demonstrating the real-time viability of the proposed method for complex safety-critical applications.