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This paper obtains a theoretical value of the maximum transportation throughput of Automated Guided Vehicle (AGV) System in a logistics center. To know the maximum transportation throughput is important to design the system since we need to know the feasibility of the design. It is proposed that the method which the problem to obtain the maximum transportation throughput is reduced to a linear programming...
This paper proposes a new model checking method to detect falsification on control system software. In the previous study, we have examined a method which detects illegal rewriting for control system software via Petri Net and Kalman Decomposition (KD). In this paper, in order to divert this method to model checking, we consider a new toolchain with the existing model checker SPIN. Specifically, we...
This paper presents a variable adaptive law, which is robust to bounded disturbances. Combining with the dead zone, the proposing adaptive law uses a sort of the σ-modified adaptive law in the small estimation error region. Viability of the adaptive law, in comparing with the dead zone type adaptive law, is shown by theoretical analysis and a simple numerical simulation.
This paper considers a sampled-data model following control for continuous-time discrete-valued input systems. The synthesis problem the authors address is the simultaneous synthesis of the nominal controller and the dynamic quantizers. A synthesis condition is recast as a set of matrix inequalities via the matrix uncertainty approach, while the quantized accuracy and the sampling time of discretizing...
This paper aims to propose a fallback system isolated from man-in-the-middle attack (MITM) for networked control systems. In this paper, fallback is an incident response of the control system in which facilities are preferentially protected and a minimal system operates during MITM. Since the communication contents of the networked control systems can be tampered with by MITM, the proposed system...
This paper considers a sampled-data model following control for continuous-time discrete-valued input systems. A synthesis condition is recast as a set of matrix inequalities via the matrix uncertainty approach, while the quantized accuracy and the switching speed of discretizing the continuous-valued signal are considered simultaneously. To reduce the conservativeness of the synthesis condition,...
This paper considers reduced-order dynamic quantizer synthesis for discrete-valued input systems. Our approach is based on the ellipsoidal invariant set analysis and the slack variable approach of linear matrix inequality. We consider the tractable numerical design, which covers the full-order design result of the current authors. In the numerical examples, the effectiveness of the slack variable...
Recent control systems of critical infrastructures are networked systems, which are exposed to the infection of the computer malwares. This paper considers a cybersecurity technology of networked control systems in terms of availability. Architecture of fallback control is proposed, which consists of the remote controller and the local controller. The former achieves the high control performance and...
This paper presents a present status of cyber security of critical infrastructures, which are controlled by microcomputers and connected through the network system, including Internet. There is strong possibility of cyber attack and some defense is necessary. The defense along Control System Security Center, which is established in 2012, is shown here.
To enhance the security of networked control systems, we propose the concept of secured control rules that is defined as a method that achieves concealing both signals over communication channels and parameters within controllers. Our method proposed in this study uses the homomorphism of the RSA cryptosystem to determine control signals directly from encrypted feedback signals and control parameters...
This paper proposes a new scheduling method of dispatching and conflict-free routing for overhead hoist transport (OHT) systems in semiconductor fabrication (Fab). This paper utilizes a model predictive control (MPC) strategy in which the cycle of measurement, prediction, optimization and control is repeated. The first aim of the MPC application is to set a small prediction horizon for the scheduling...
Recently, automobile industry requires energy saving technology for reducing the environment burden and operational costs. Hybrid engines are environmental friendly, but hybrid heavy-duty trucks have not been still sold in the Japanese market, as their development has posed considerable problems. To solve these problems, the automobile industry has begun to develop simulation models of actual vehicles...
This paper proposes a smartphone centered system where home appliances cooperate with each other. This system realizes convenience of a consumer as low cost and high secure environment by Near Field Communication (NFC) and a Cloud Server consists of Social Networking Service (SNS) and a Virtual Server (VS). Moreover, Verbal Communication (VC) through the smartphone is added for usability. A cooking...
This paper considers an adaptive observer construction for summational type state space (StSS) equation, which is a suitable mathematical expression for modeling physical dynamical systems with parasitic elements. Although this expression is appropriate to the realities of physical and engineering problems in terms of the system identification and the control system design, to our knowledge, little...
This paper considers output feedback control for continuous-time discrete-valued input systems. Our controller achieves model following control for networked control systems and embedded devices with low-resolution AD/DA converters. The synthesis problem we address is simultaneous synthesis of a nominal controller and a delta-sigma modulator (the modulator is called a dynamic quantizer). Our approach...
This paper considers a task scheduling problem in heterogeneous systems of processors and proposes a multistep scheduling algorithm for the problem. There are two important points for task scheduling problem. First, it is necessarily to consider optimality. Second, it is necessarily to reduce scheduling time which is calculation time for the problem. For first point, idle time and communication costs...
This paper considers an output feedback control for discrete-valued input systems. Our controller achieves model following control for networked control systems and embedded devices with low-resolution AD/DA converters. The synthesis problem we address is the simultaneous synthesis of the nominal controller and the delta-sigma modulator (where the modulators are called the dynamic quantizers). Our...
This paper considers a task scheduling problem for multicore CPUs and proposes a multistep scheduling algorithm. The existing scheduling algorithms formulated as 0–1 integer linear programming can consider optimality of a task scheduling. However, the existing scheduling algorithms cannot address complicated relations among tasks or cannot consider communication costs among processors. Then, first...
This paper proposes a new static simultaneous optimization of dispatching and conflict-free routing for unidirectional Overhead Hoist Transport (OHT) systems. Our objective is to minimize the entire transportation time where the given transportation tasks are finished. A hybrid system modeling is applied for OHT system that is constituted by the OHT vehicles at the lower level and governed by the...
This paper considers an output feedback control for quantized feedback systems. Our controller provides high accuracy control performance for embedded devices with low-resolution AD/DA converters. For a certain system, we provide closed form and numerical solutions for the synthesis problem. The synthesis problem we address is the simultaneous synthesis of the nominal controller and the delta-sigma...
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