Article
Engineering, Mechanical
Rupam Singh, Bharat Bhushan
Summary: Unmanned helicopters have gained popularity due to their versatility in various applications, but their automatic control systems face challenges due to nonlinearity and disturbances. Research on robust flight control methods is essential for enhancing safety and system management of helicopters.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Computer Science, Hardware & Architecture
Clara Hobbs, Bineet Ghosh, Shengjie Xu, Parasara Sridhar Duggirala, Samarjit Chakraborty
Summary: Checking the safety of feedback control loops on complex and distributed embedded systems is crucial for emerging autonomous systems. Analyzing quantitative properties like maximum deviation involves computationally expensive reachability analysis, but suitable approximation strategies can address this bottleneck. Identifying the best combinations of control and deadline miss handling strategies for individual systems and timing uncertainties is possible with these quantitative safety property checks.
IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS
(2022)
Article
Automation & Control Systems
Sergiy Bogomolov, Goran Frehse, Amit Gurung, Dongxu Li, Georg Martius, Rajarshi Ray
Summary: This paper investigates the falsification problem of hybrid systems and proposes leveraging symbolic reachability techniques to improve the scalability of falsification algorithms. By adding linear state constraints to reduce the search space of the optimization problem, an alternating minimization algorithm is presented to solve falsification problems.
NONLINEAR ANALYSIS-HYBRID SYSTEMS
(2021)
Article
Automation & Control Systems
Mohamed Serry, Gunther Reissig
Summary: This paper presents a method to approximate reachable tubes for linear continuous-time time-varying control systems. The method utilizes numerical approximations and transition matrices to handle uncertainties in initial states and inputs, and demonstrates a variant for different uncertainty cases.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Computer Science, Information Systems
Zhongjie He, Jianning Li
Summary: This paper studies a robust iterative learning control approach for a class of nonlinear systems with nonparametric uncertainties and time-iteration-varying parametric uncertainties. By using a barrier Lyapunov function for controller design and incorporating alignment condition and robust learning method, excellent tracking performance and constraint control can be achieved.
Article
Automation & Control Systems
Wendi Huang, Min Wu, Luefeng Chen, Jinhua She, Hiroshi Hashimoto, Seiichi Kawata
Summary: This article discusses the trajectory optimization problem of a drilling process and proposes a new method OR-NSGA-II to solve the multi-objective optimization problem with parameter uncertainties. The method effectively reduces the negative effects of parameter uncertainties and ensures population diversity through the outlier removal mechanism and improved crowding distance calculation.
IEEE TRANSACTIONS ON SYSTEMS MAN CYBERNETICS-SYSTEMS
(2022)
Article
Environmental Studies
Qian Ding, Jianbai Huang, Hongwei Zhang
Summary: The study reveals that the effects of financial and geopolitical uncertainties on commodity markets are concentrated in the short term, with volatility being more impacted than returns. Different types of financial uncertainty shocks have varying effects on commodity futures volatility, with financial stress shocks having relatively large impacts, especially post-global financial crisis. Furthermore, shocks caused by financial liquidity increase commodity returns only in the short term.
Article
Automation & Control Systems
Qiang Chen, Xinqi Yu, Mingxuan Sun, Chun Wu, Zijun Fu
Summary: This article proposes an adaptive repetitive learning control (ARLC) scheme for PMSM servo systems with bounded nonparametric uncertainties, ensuring high steady-state tracking accuracy without the need for prior knowledge on uncertainty bounds in controller design. This approach divides uncertainties into two parts and utilizes different strategies for each part to achieve effective compensation and superior performance.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2021)
Article
Automation & Control Systems
Luan Viet Nguyen, Hoang-Dung Tran, Taylor Johnson, Vijay Gupta
Summary: This article presents a decentralized safe control approach for distributed cyber-physical systems, which utilizes real-time reachability analysis to ensure safety and collision-free guarantees. The proposed method predicts collision risks and updates waypoints and control strategies for achieving mission goals.
IEEE TRANSACTIONS ON CONTROL OF NETWORK SYSTEMS
(2023)
Article
Energy & Fuels
Hossein Sartipizadeh, Farnaz Harirchi, Mohammad Babakmehr, Payman Dehghanian
Summary: The DC-DC Floating Interleaved Boost Converter (FIBC) is introduced to convert low-level voltage generated by renewable energy sources to high-level voltage required for AC inverters. Designing a proper voltage gain for FIBC is challenging due to uncertainties, such as variations in input voltage caused by parameters like external load. A robust model predictive control is used to regulate the output voltage despite uncertainties, eliminating the need for individual tuning for each converter. This approach is demonstrated to be superior to non-robust model predictive framework in simulations.
IEEE TRANSACTIONS ON ENERGY CONVERSION
(2021)
Article
Automation & Control Systems
Ronghu Chi, Yu Hui, Chiang-Ju Chien, Biao Huang, Zhongsheng Hou
Summary: This article proposes a new convergence analysis method for sampled-data iterative learning control systems, considering LLC nonlinear nonaffine systems and relaxing repetitive conditions. It proves the bounded convergence of tracking error and further investigates the relationship between error bounds and iteration-varying uncertainties and sampling periods.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2021)
Article
Engineering, Mechanical
Ping Liu, Sen Chen, Zhi-Liang Zhao
Summary: This paper introduces a new control method to address the challenges posed by mismatched nonlinear uncertainties and unknown control coefficients, with a design process involving determining the equivalent integrators chain form, constructing an extended state observer, and designing a dynamic system to generate the desired input signal. Theoretical results demonstrate the strong robustness of the proposed method to mismatched uncertainties and unknown control coefficients.
NONLINEAR DYNAMICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Dilaksan Thillaithevan, Paul Bruce, Matthew Santer
Summary: We demonstrate a methodology for robust optimization using multivariable parameterized lattice microstructures. By introducing material uncertainties at the microscale, we are able to simulate manufacturing variations and design structures tolerant to those variations. We impose different types of material uncertainties to generate more robust structures.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Automation & Control Systems
Muhammad Syifa'ul Mufid, Dieky Adzkiya, Alessandro Abate
Summary: This article focuses on the reachability analysis of interval max-plus linear systems and presents algorithms for verifying system trajectories that eventually reach a target set. By encoding the system, initial set, and target set into linear real arithmetic expressions and using a satisfiability modulo theory solver, the developed algorithms demonstrate superior performance compared to existing methods.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Automation & Control Systems
Hefu Ye, Yongduan Song
Summary: This note presents a control solution for achieving zero-error tracking in high-order MIMO nonlinear systems. The proposed control can achieve precise tracking within the prescribed time regardless of initial conditions, uncertainties, and disturbances.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Ethics
David J. Hess, Dasom Lee, Bianca Biebl, Martin Fraenzle, Sebastian Lehnhoff, Himanshu Neema, Juergen Niehaus, Alexander Pretschner, Janos Sztipanovits
Summary: This study develops a comparative sociotechnical design perspective for interdisciplinary teams, focusing on technical and governance challenges and their interplay. With a triple comparative perspective, the research explores issues across different technological systems, societal implications, and continents, providing insights on values, solution portability, and policy harmonization potential. Through international collaboration, the study offers practical applications for research and teaching.
JOURNAL OF RESPONSIBLE INNOVATION
(2021)
Article
Computer Science, Information Systems
Erzana Berani Abdelwahab, Martin Fraenzle
Summary: This research demonstrates that adding natural constraints to the model of delayed feedback channels effectively reduces the complexity caused by delays. The reduction is based on a sampling approach that is applicable when specific conditions on the feedback are satisfied. Furthermore, the method has potential for application in mixed discrete-continuous dynamics of delayed hybrid systems.
IT-INFORMATION TECHNOLOGY
(2021)
Article
Physics, Condensed Matter
Till Kahlke, Martin Fraenzle, Alexander K. Hartmann
Summary: Numerically studying the maximum z-matching problem on ensembles of bipartite random graphs has shown results on the capacity and energy of the optimum matchings. Confirming analytical results for bipartite regular graphs and observing the same scaling behavior as standard matching for finite size behavior indicate the universality of the problem. Investigating saturability in bipartite Erdos-Renyi random graphs based on average degree revealed phase transitions between unsaturable and saturable phases, coinciding with changes in the running time of the matching algorithm.
EUROPEAN PHYSICAL JOURNAL B
(2021)
Article
Automation & Control Systems
Bai Xue, Naijun Zhan
Summary: This article investigates the estimation problem of the maximal robust invariant set for discrete-time perturbed nonlinear systems within the optimal control framework. The main contribution is reducing the problem to solving a Bellman type equation, and using numerical methods to provide an approximation of the maximal robust invariant set. Two examples demonstrate the performance of the Bellman equation based method.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Computer Science, Theory & Methods
Martin Fraenzle, Mahsa Shirmohammadi, Mani Swaminathan, James Worrell
Summary: This paper investigates the Pareto analysis of multi-priced timed automata (MPTA) and studies the Pareto Domination Problem. The results show that this problem is decidable for MPTA with at most three observers, but undecidable in general. Additionally, an approximate Pareto Domination approach is considered, which can be decided in exponential time.
INFORMATION AND COMPUTATION
(2022)
Article
Computer Science, Theory & Methods
Xiong Xu, Shuling Wang, Bohua Zhan, Xiangyu Jin, Jean-Pierre Talpin, Naijun Zhan
Summary: This paper presents a method to efficiently design safety-critical cyber-physical systems (CPS) by combining AADL and Simulink/Stateflow (S/S) for co-modeling and verification. The proposed approach provides a unified graphical modeling environment and supports simulation through C code generation.
THEORETICAL COMPUTER SCIENCE
(2022)
Article
Computer Science, Artificial Intelligence
Bernd Finkbeiner, Martin Fraenzle, Florian Kohn, Paul Kroeger
Summary: Signal Temporal Logic is a linear-time temporal logic used for classifying time-dependent signals and monitoring cyber-physical systems. Existing algorithms assume perfect identity between sensor readings and ground truth, but we proposed an extended analysis to address inexact measurements and provide more informative monitoring verdicts. We developed optimal evaluation algorithms based on affine arithmetic and SAT modulo theory to solve the problem of inconclusive state estimations.
Article
Computer Science, Theory & Methods
Qiuye Wang, Mingshuai Chen, Bai Xue, Naijun Zhan, Joost-Pieter Katoen
Summary: We present an invariant barrier-certificate condition for ensuring unbounded-time safety of differential dynamical systems. The condition, which is the weakest possible one to achieve inductive invariance, can be encoded as an optimization problem subject to bilinear matrix inequalities (BMIs). We propose a synthesis algorithm based on difference-of-convex programming that approaches a local optimum of the BMI problem through solving a series of convex optimization problems. Our method, incorporated in a branch-and-bound framework, demonstrates effectiveness and efficiency in finding barrier certificates for ensuring safety.
INFORMATION AND COMPUTATION
(2022)
Article
Automation & Control Systems
Shuyuan Zhang, Shizhong Song, Lei Wang, Bai Xue
Summary: This paper investigates stability verification for heterogeneous polynomial complex networks using an iterative sum-of-squares programming approach. By introducing polynomial Lyapunov functions, a global asymptotic stability criterion is established for the heterogeneous complex networks under directed topology. The stability verification problem is reduced to a sum-of-squares optimization problem for solving polynomial matrix inequalities based on the proposed criterion. An iterative sum-of-squares programming approach is presented to handle the non-convex terms of the polynomial matrix inequalities, effectively achieving stability verification with polynomial Lyapunov functions. A numerical example demonstrates the theoretical and algorithmic advantages of the proposed method in fully automatic verification of global asymptotic stability for heterogeneous polynomial complex networks.
IEEE CONTROL SYSTEMS LETTERS
(2023)
Article
Computer Science, Software Engineering
Shenghua Feng, Mingshuai Chen, Han Su, Benjamin Lucien Kaminski, Joost-Pieter Katoen, Naijun Zhan
Summary: In this paper, a new proof rule is proposed for verifying lower bounds on quantities of probabilistic programs. Unlike existing rules, this proof rule is not limited to almost-surely terminating programs and can be applied to establish non-trivial lower bounds on termination probabilities and expected values for potentially divergent probabilistic loops, such as the well-known three-dimensional random walk on a lattice.
PROCEEDINGS OF THE ACM ON PROGRAMMING LANGUAGES-PACMPL
(2023)
Article
Automation & Control Systems
Changyuan Zhao, Shuyuan Zhang, Lei Wang, Bai Xue
Summary: This article investigates the problem of approximating robust reach-avoid sets for discrete-time polynomial dynamical systems subject to disturbances over open time horizons. The robust reach-avoid set can be characterized exactly via a Bellman-type equation, but due to the challenge in solving it analytically, a reformulation is proposed to approximate the solution using novel constraints. When the involved data are polynomials, the problem can be encoded into a semidefinite program and efficiently solved using interior point methods. Several examples are provided to demonstrate the performance of the proposed method.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Computer Science, Software Engineering
Janis Kroeger, Bjoern Koopmann, Ingo Stierand, Martin Fraenzle
Summary: The design of safety-critical systems requires the rigorous application of specification and verification methods. This paper presents an extension of a framework for timing property specification, which addresses the explicit handling of operating modes and transitions, reducing the complexity of verification. Formal semantics are provided to reason about the specifications and contract operations, enabling statements about mode composition. The results are illustrated through a real-world example.
INNOVATIONS IN SYSTEMS AND SOFTWARE ENGINEERING
(2023)
Proceedings Paper
Computer Science, Hardware & Architecture
Janis Kroeger, Bjoern Koopmann, Ingo Stierand, Nadra Tabassam, Martin Fraenzle
Summary: This paper presents an extension of a framework for specifying timing properties in contract-based design paradigm. By enhancing the specification language, it allows for specifying mode-dependent behavior and mode transitions. A formal specification is provided for reasoning and making statements about mode composition.
VERIFICATION AND EVALUATION OF COMPUTER AND COMMUNICATION SYSTEMS (VECOS 2021)
(2022)
Proceedings Paper
Automation & Control Systems
Bai Xue, Renjue Li, Naijun Zhan, Martin Franzle
Summary: This paper investigates the reach-avoid problem of stochastic discrete-time systems over open time horizons, using iterative polynomial maps with stochastic disturbances to model the system and computing an inner approximation of its p-reach-avoid set to ensure safety.
2021 AMERICAN CONTROL CONFERENCE (ACC)
(2021)