Kai-Yuan Cai’s research while affiliated with Osaka University and other places

... Several papers consider the navigation of autonomous robots. In both [253] and [254] the synthesized supervisor is used to ensure nonblocking and safe execution of each robot once it has been assigned a task from a higher-level (external) task-planning module. Both deploy several supervisor architectures like monolithic, modular, and decentralized synthesis. ...

Reference:

Offline supervisory control synthesis: taxonomy and recent developments

... These approaches are less conservative and impose fewer conditions on the system, but proving stability and achieving acceptable control performance with active methods is more challenging. Great works on both active and passive fault approaches have been published; the reader can refer to [6][7][8] for more details. This paper introduces an active FTC approach for nonlinear time-delay systems using adaptive dynamic programming (ADP). ...

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Fault-tolerant control for nonlinear time-delay systems using neural network observers

... Moreover, the distributed information can be gathered by a Supervisory Control And Data Acquisition (SCADA) system (Figueiredo, 2008), which controls and supervises the overall performance of the CPS. An advantageous direction to control CPSs is the supervisor control theory, in the Ramdage-Wonham (RW) framework (Cassandras & Lafortune, 2021;Ramadge & Wonham, 1987;Wonham & Cai, 2019). In the supervisor control theory, the desired performance of a CPS is described as desired regular languages, realized by appropriate supervisor automata. ...

Reference:

Event‐based supervisor control for a cyber‐physical waterway lock system

... In real life, we refer to entities that have independent thoughts and can interact with the surrounding environment as agents. The problem of consensus is that all agents converge to a certain state with the evolution of time, which is of great practical significance and theoretical value as the basis for cooperative coordination and control between agents [5,6]. In [7], the authors discuss the problem of consensus under fixed topologies through event-triggered control. ...

Reference:

Consensus of multi-agent systems with randomly occurring nonlinearities via uncertain pinning control under switching topologies

... where p j,k is the position of the center mass of robot j at time k, E = diag (a j , b j , c j ) is an invertible scaling matrix to bound the boundary of the ellipse. The details of designing E can be found in Quan et al. (2023a). If the robot i is regarded ...

Reference:

Optimal virtual tube planning and control for swarm robotics

... In recent years, with the wide application of the multicopter [1][2][3][4], its safety has become increasingly important [5,6]. As the power of multicopter, the failure of rotors is a significant threat to the safety of the multicopter. ...

Reference:

Analysis of a Uniform Passive Fault-Tolerant Control Method for Multicopters

... This candidate is then incrementally refined by preventing events enforcing controllability and non-blockingness least-restrictively until an admissible controller control(Γ ) is obtained (closedness under arbitrary union also implies that the order in which violations of controllability and non-blockingness are resolved is insignificant). Note that this fixed-point procedure supports also cyclic LTSs in general (in which, as usual, loops may delay the visiting of safe states indefinitely as opposed to [55]). To handle the case with priorities, we resolve priorities among uncontrollable events before applying the fixed-point procedure and resolving priorities of remaining controllable steps afterwards to obtain the priority-aware controller pControl(Γ ). ...

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Combining Look-ahead Design-time and Run-time Control-synthesis for Graph Transformation Systems

... where N = N + Δ N . Therefore, with (36) in consideration, ...

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Uniform Passive Fault-Tolerant Control of a Quadcopter With One, Two, or Three Rotor Failure

... The concept of usability-aware cost levels was introduced by Matsui and Cai (2021b), which takes into account the impact of the protection policy on the system's usability. That is, the impact on the services/functions provided by the system when a protection is implemented at a certain location, determining if such protection is too costly. ...

Reference:

A classification of cybersecurity strategies in the context of Discrete Event Systems

... Lemma 1 ( [27]): Based on Assumptions 4 and 5, assume that the velocity command for the ith robot is (20). Then there exist sufficiently small ϵ m and ϵ s > 0 in u 2,i , and a sufficiently small ϵ t > 0 in u 3,i , such that S i (t) ∩ S j (t) = ∅ and S i (t) ∩ ∂T ′ = ∅ for all initial positions p i (0), t > 0, i, j = 1, · · · N , i ̸ = j. ...

Reference:

Navigating Robot Swarm Through a Virtual Tube with Flow-Adaptive Distribution Control