小西 康夫

This study proposes a data-driven approach for controlling a dual-rate sampled-data system using the lifting technique, where the sampling interval of the plant output is longer than the holding interval of the control input. In the proposed method, the structure of the dual-rate controller is linearized to its controller parameter, and the controller parameter is optimized using noniterative correlation-based tuning. Furthermore, intersample ripples are eliminated because the difference in the control inputs between sampled outputs is weighted. The effectiveness of the proposed method is demonstrated through numerical and experimental examples.

The aim of the present study is to improve the understanding of the control engineering for university students through the experience of the control experiment, and hence an experimental device is developed. The students are educated the control engineering using the device, and the educational effect is evaluated. In the present study, the students take examinations for the control engineering before and after the experiment, and the effect is evaluated objectively.

This paper proposes a method for determining a high accuracy posture for serial redundant manipulators with parametric uncertainty that suppresses the effect of the uncertainty. In the proposed method, the uncertainty variance is introduced as an index for quantifying the magnitude of the distribution of the end-effector coordinates of the manipulator caused by the uncertainty, and the posture is determined by using the uncertainty variance as an evaluation function of posture. In order to efficiently calculate the uncertainty variance, the method includes a calculation method based on the polynomial chaos theory. The effectiveness of the method is confirmed by a posture determination simulation of a serial redundant manipulator with uncertainty. In this simulation, it is confirmed that the calculation of the uncertainty variance can be achieved by the method using the polynomial chaos theory, and that the proposed method can determine the high-accuracy posture that suppresses the effect of the uncertainty.

The present study discusses an optimal design method of a proportional integral derivative (PID) control system for a continuous-time second-order plus dead-time system (SOPDT) that includes an under-damping system. The proposed PID control system is designed to minimize the performance index defined as the tracking performance for the set-point or the regulation performance for the disturbance, where the assigned stability margin is also achieved in order to attain robust stability for the modeling error. Because of the relationship between tracking performance and robust stability, the PID parameters are decided such that the tracking performance is optimized subject to the user-specified stability margin. In the proposed design method, in order to obtain the most general optimal PID possible parameters for controlled plants, we discuss a design method based on a normalized plant model. As a result, the PID parameters are seamlessly optimized between over-damping, critical-damping, and under-damping systems. The effectiveness of the proposed method is demonstrated through numerical examples.

This study proposes a new design method for the mobile robot trajectory generation considering obstacle avoidance using mixed integer linear programming (MILP). In the proposed method, the velocity of a mobile robot as well as the position of the mobile robot are used in the initial condition of MILP. Numerical examples show that the mobile robot collides with obstacles using a conventional method, in which the velocity is not taken into account, and on the other hand, the problem is resolved using the proposed method.

A dual-rate sampled-data control system is designed in which the sampling interval of measured signals is twice as long as the holding interval of a control input. In the proposed method, a control law is extended based on the null space and intersample ripples are eliminated without changing the sampled output trajectory in the steady state. Polynomial and state-space approaches are conventional open-loop design methods based on the null space. However, conventional methods are ineffective for unstable systems and are unavailable when the null space of the plant model is only the zero vector because the controlled plant is not arbitrarily selectable. On the other hand, the proposed method is effective for unstable systems, as well as stable systems, even when the null space of the plant model is only the zero vector, because the proposed controller is designed based on a closed-loop system.

The aim of the present study is to improve the understanding of the control engineering for university students through the experience of the control experiment, and hence an experimental device is developed. The students are educated using the device, and the educational effect is evaluated. In the present study, the students take examinations for the control engineering before and after the experiment, and the effect is evaluated objectively.

© 2013 IEEE. The present study discusses the consensus control of dual-rate multi-agent systems, where the sampling/communication interval of quantized data is an integer multiple of the control interval. A conventional multi-agent system uses a dynamic quantizer which is designed in a single-rate system where the intervals are equal, i.e., the control interval length is the same as the communication interval length. However, a dynamic quantizer designed in a dual-rate system is expected to have improved control performance. In the present study, an objective function is divided into a quantization term, which is related to the quantization error, and the remaining term. The proposed dual-rate dynamic quantizer is designed such that the quantization term is minimized. Finally, in numerical examples, the proposed dual-rate method is quantitatively evaluated by comparing with the conventional single-rate method, and the effectiveness of the proposed method is demonstrated.

© 2019 IEEE. Multi-agent systems (MASs) are used for distributed control purposes and substantial research attention has been directed to these systems because of their practical merits. In MASs, agents' information is shared through networks. In networked-control systems, the measured data is usually quantized because of sensor performance or specification, and its resolution is inadequate. Furthermore, because of network quality, the measurement interval is often longer than the control interval. Therefore, the present study introduces a design method for a dual-rate quantized control system, in which the measurement interval of agents is an integer multiple of the control interval.

In this paper, we consider the consensus control of multiagent systems with quantized signal communication. In such a network system, when the static quantizer is used, the control performance is degraded because of the influence of the quantization error. To compensate the quantization error, in a conventional method, a probabilistic quantizer is used. On the other hand, in this paper, the dynamic quantizer is introduced instead of the static quantizer. Because the dynamic quantizer is optimally designed, the control performance of the proposed method can be improved better than the conventional methods. Finally, the effectiveness of the proposed method is demonstrated through numerical examples.

This study proposes a new design method for a dual-rate cascade control system, in which the interval of the outer loop is longer than that of the inner loop. In the proposed method, the controller parameters are optimized off-line using the controlled data. The effectiveness of the proposed method is demonstrated through numerical simulations.

© 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. The present paper discusses a design method for a single-input single-output linear time-invariant dual-rate sampled-data control system, where the sampling interval of a plant output is longer than the holding interval of a control input. In such a control system, intersample output oscillation, called ripple, can occur even if the sampled output converges to the reference input. In order to resolve this problem, two design methods have been proposed such that the existing sampled output response is maintained: an open-loop system design method and a closed-loop system design method. However, the open-loop design method cannot be applied to systems for which the gain matrix of the control input is full rank. On the other hand, the closed-loop design method can be used for such systems, but the sampled output response is maintained only in the steady state. The present study proposes a new closed-loop design method in which ripples are eliminated and both the transient and steady-state responses are maintained. The effectiveness of the proposed method is demonstrated through numerical examples. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

© 2019 The Institute of Electrical Engineers of Japan. This letter proposes a new design method for controlling a dual-rate sampled-data control system, in which the sampling interval of a plant output is an integer multiple of the holding interval of a control input. In the proposed method, a discrete-time control law is extended such that the existing discrete-time response is maintained. As a result, the control law is re-designed independent of the reference response as well as the disturbance response in discrete time.

© 2019 The Institute of Electrical Engineers of Japan. This paper considered a backward path-tracking control method for an articulated vehicle. One of the most effective method in this research area is the exact feedback linearization based approach. Although this method can design the control law systematically, the controller has singular point that the control law cannot be defined. One such a singular point is the situation which the angle between a tractor and a trailer is the right angle. To avoid such an uncontrollable situation and improve the control performance, we proposed a method which is added a new input to the exact feedback linearization controller. This additional input constraints the change of the angle and avoids the vehicle to approach the singular point. The stability of the additional input was discussed by the Lyapunov's direct method. To confirm the effectiveness of our proposed method in actual use, we carried out the tractor-trailer model experiment. In this experiment, the FastSLAM method was employed to estimate the location of the model. The experimental result indicated that our proposed method was fasible even if the actual system

© 2019 The Institute of Electrical Engineers of Japan. This paper discusses a design method for a single-input single-output multi-rate sampled-data control system, where the sampling interval of a plant output is an integer multiple of the hold interval of a control input. In such a sampleddata control system, the intersample output can oscillate even if the sampled output converges to the reference input. Because of the oscillation, heavy load is on the actuator, and the control performance is deteriorated. To resolve the problem, in a conventional method, a control law is extended using the null-space, and the intersample response is improved such that the sampled response is maintained. The conventional method has been designed based on the transfer function representation. In the proposed method, on the state-space representation, the null-space is introduced, and the existing control system is extended. Finally, through numerical examples, the effectiveness of the proposed method is verified.

© 2019 Institute of Electrical Engineers of Japan. All Rights Reserved. This study proposes a data-driven control method for a dual-rate sampled-data control system, where the sampling interval of a plant output is shorter than the holding interval of a control input. The proposed data-driven method is based on an open-loop input/output data. Therefore, the controller parameter is optimized using only the one-shot controlled data. Finally, the effectiveness of the proposed method is demonstrated through a numerical example.

This study proposes a new design method for the consensus control of multi-agent systems with quantized signal communication. When the static quantizer used, the performance of the consensus control is deteriorated depending on the quantizing level. In a conventional method, the quantization is implemented the probability function. On the other hand, in the proposed method, the dynamic quantizer is introduced, and it is optimally designed. As a result, the consensus control performance is improved. Finally, the effectiveness of the proposed method is demonstrated through numerical examples.

© 2018 IEEE. This study discusses a space-space design method for controlling a single-input single-output dual-rate system, where the sampling interval of a plant output is longer than the holding interval of a control input. In such a dual-rate control system, the intersample output can oscillate even if the sampled output converges to the reference input. In the proposed method, an existing control law is extended using the null-space so that the intersample ripple is eliminated. As a result, the intersample output response is redesigned independent of the sampled output response. Finally, through numerical examples, the effectiveness of the proposed method is verified.

The present study discusses a data-driven control method for the single-input single-output (SISO) dual-rate control system, in which the sampling interval of the plant output is shorter than the holding interval of the control input. Using the lifting technique, the SISO dual-rate system is converted to the single-input multi-output (SIMO) single-rate system, where the sampling intervals are the same as the holding interval, and the controller parameters are optimized using only the open loop data. Finally, the effectiveness of the proposed method is demonstrated through numerical examples.

This paper presents a proportional-integral-derivative (PID) control system design method for discrete-time first-order plus dead-time plants. Because the relation between the tracking performance and the robust stability is the trade-off, the PID parameters of the PID control system are decided such that the tracking performance is optimized subject to the assigned robust stability, where the reference or disturbance response is selected as the tracking performance. In the proposed method, the PID parameters decision method is designed using a neural network with an extreme learning machine. Hence, the optimal PID parameters are obtained based on the trade-off between the tracking performance and the robust stability. Furthermore, the proposed design method is extended as the adaptive control, and hence an unknown or time-varying plant, is well controlled using the proposed method. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley &amp Sons, Inc.

The present study proposes a new approach to a data-driven PID control design method based on one-shot closed-loop input and output data. Even if the proposed controller is designed using only one-shot data, both the prescribed robust stability and tracking performance optimization are attained. The proposed control law is designed by solving a constrained optimization problem, in which the robust stability as a constraint condition is designed by a sensitivity function estimated using the discrete-time Fourier transform, and the performance function defined using a fictitious reference is minimized. As a result, the proposed method provides trade-off design between the tracking performance and robust stability, where the robust stability is arbitrarily selected depending on the plant perturbation. The effectiveness of the proposed method is demonstrated through numerical examples.

This study proposes a new design method for controlling a multi-input single-output dual-rate system, where the sampling interval of the plant output is longer than the hold intervals of the control inputs. Using the lifting technique, the dual-rate system is converted to the multi-input multi-output single-rate system, and the controller parameters are optimized based on one-shot closed-loop data. Finally, the effectiveness of the proposed method is demonstrated through numerical examples. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley &amp Sons, Inc.

This paper proposes a new design method for controlling the dual-rate sampled-data control system, in which the sampling interval of a plant output is longer than the holding interval of a control input. In such a sampled-data control system, the continuous-time plant is controlled by the discrete-time controller using the sampled output, and hence the intersample response is designed as well as the sampled output response. In the proposed method, the dual-rate control system is extended independent of the discrete-time response. Furthermore, the intersample response for the disturbance is improve without changing the existing sampled response.<bold> </bold>

In the control education, students are able to understand the control theory intuitively through the education using experiments. In this study, the authors develop an experimental device for the control education. By using the device, it is possible for students to comprehend the control through experience and to enhance the students comprehension in the control. In the device, a controlled object is floated by rotating a propeller, and the floating level is adjusted by controlling the angular velocity of the propeller. Further, students recognize the control effect resulted from the control actuation since the propeller is rotating while the object is floated. The floating device is developed of commercial components, and hence, an experimental setup can be prepared at a low price. Students are educated on the control theory using the device, and its effectiveness is validated. In the control education, the device operation method and the control theory are explained alternately. From the questionnaire before and after the experiment, the effectiveness of the control education using the device is demonstrated.

Copyright © 2018 by ISFA The present study discusses a design method for controlling a twin-motor system, where a shaft is actuated by two direct-current (DC) motors. In order to optimize controller parameters such that the trajectory of the rotation speed of the shaft follows that of the reference model, fictitious reference iterative tuning (FRIT) is used. To decide the controller parameters of a two-input one-output system using FRIT, the system is designed as a dual-rate system. Finally, the designed controller parameters are applied to an experimental setup, and its effectiveness is demonstrated.

<p>In this paper, we propose an active fault detection scheme with input redundancy of the plant. The proposed active fault detection scheme aims at quickly detecting of the occurrence of actuator sticking under steady state. In addition, a new fault tolerant control (FTC) design is developed to implement the active fault detection scheme for input redundant 2-input 1-output plant. Finally, the effectiveness of the proposed FTC and the applicability of the proposed active fault detection scheme are verified through several experiments.</p>

© 2017 IEEE. The present study proposes a design method for a single-input single-output dual-rate control system, in which the sampling interval of the plant output is twice the hold interval of the control input. In such a dual-rate control system, intersample ripples might occur even if the discrete-time response converges to a reference input because the control input can be updated between sampling intervals. The present study proposes a new design method for eliminating the intersample ripples without changing a pre-designed discrete-time response. In the proposed method, a pre-designed control law is extended using redundant input in the dual-rate control system, and the intersample response is enhanced independent of the discrete-time response.

This study proposes a new design for generalized predictive control in a multirate system in which the sampling interval of the plant output is an integer multiple of the hold interval of the control input. We design a system with one degree of freedom, and then, for integral action we extend it to two degrees of freedom. Because the integral compensation is revealed only when a modeling error or a disturbance arises, the integral compensation does not cause the transient response to deteriorate when these are absent. Moreover, even if there is a modeling error or a step-Type disturbance, the plant output converges to the step-Type reference input, because the integral compensation is revealed. The proposed design is based on a state-space representation, and hence it can be easily extended to a multivariate system.