著者

Kaito Sato Kenji Sawada

出版者

Fuji Technology Press Ltd.

雑誌

Journal of Robotics and Mechatronics (ISSN:09153942)

巻号頁・発行日

vol.35, no.2, pp.298-307, 2023-04-20 (Released:2023-04-20)

参考文献数

21

被引用文献数

1

---

In vehicle control, state estimation is essential even as the sensor accuracy improves with technological development. One of the vehicle estimation methods is receding-horizon estimation (RHE), which uses a past series of the measured state and input of the plant, and determines the estimated states based on linear or quadratic programming. It is known that RHE can estimate the vehicular state to which the extended Kalman filter cannot be applied owing to modeling errors. This study proposes a new computational form of the RHE based on primal-dual dynamics. The proposed form is expressed by a dynamic system; therefore, we can consider the computational stability based on the dynamic system theory. In this study, we propose a continuous-time representation of the RHE algorithm and redundant filters to improve the convergence performance of the estimation and demonstrate its effectiveness through a vehicle path-following control problem.

著者

Takuma WAKASA Kenji SAWADA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)

巻号頁・発行日

pp.2020KEP0009, (Released:2021-05-12)

---

This paper proposes a switched pinning control method with a multi-rating mechanism for vehicle platoons. The platoons are expressed as multi-agent systems consisting of mass-damper systems in which pinning agents receive target velocities from external devices (ex. intelligent traffic signals). We construct model predictive control (MPC) algorithm that switches pinning agents via mixed-integer quadratic programmings (MIQP) problems. The optimization rate is determined according to the convergence rate to the target velocities and the inter-vehicular distances. This multirating mechanism can reduce the computational load caused by iterative calculation. Numerical results demonstrate that our method has a reduction effect on the string instability by selecting the pinning agents to minimize errors of the inter-vehicular distances to the target distances.

著者

Katsuhiko SANDO Takeshi YAMAMOTO Kenji SAWADA Tomoyuki TANIGUCHI Nobuyuki SOWA Hiroki MORI Takahiro KONDO

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

vol.8, no.2, pp.20-00497, 2021 (Released:2021-04-15)

参考文献数

11

被引用文献数

1

---

This paper describes a design method of a friction reducer device using a loading cam to suppress unstable vibration. Nonlinear simulation and energy analysis of numerical solutions demonstrates that destabilization is caused by the large phase difference between the slipping velocity in the translation direction and that in the rotation direction. It was found that similarly unstable vibration occurs in various structures using wedge rollers with translational and rotational motion. The analytical equation could be simplified by focusing on the motion factor that affects the slip velocity of the power transmission surface, which is the factor of vibration. Consequently, the design method for suppressing vibration could be expressed by a mathematical formula. This equation is validated by using the results of experiments conducted in the previous work of the current authors. Furthermore, from this equation, we proposed that vibration could be suppressed by the parameter balance of the power transmission device without using damping. The power transmission surface slips when a quick torque is input and damping is used. The proposed design can handle a quick torque response and reduce the weight of the reducer. Specifically, the shape of the wedge roller is made lighter, so that the moment of inertia of the roller is not lowered, or the wedge roller is set as a small roller.

著者

Tsubasa SASAKI Kenji SAWADA Seiichi SHIN Shu HOSOKAWA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)

巻号頁・発行日

vol.E100-A, no.10, pp.2086-2094, 2017-10-01

被引用文献数

12

---

This paper aims to propose a Fallback Control System isolated from cyber-attacks against networked control systems. The fallback control system implements maintaining functionality after an incident. Since cyber-attacks tamper with the communication contents of the networked control systems, the fallback control system is installed in a control target side. The fallback control system detects the incident without the communication contents on field network. This system detects an incident based on a bilinear observer and a switched Lyapunov function. When an incident is detected, normal operation is switched to fallback operation automatically. In this paper, a practical experiment with Ball-Sorter simulating a simple defective discriminator as a part of Factory Automation systems is shown. Assumed cyber-attacks against Ball-Sorter are Man In The Middle attack and Denial of Service attack.

著者

Hiroshi OKAJIMA Kenji SAWADA Joe KAIBE Nobutomo MATSUNAGA

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.48, no.6, pp.359-361, 2012 (Released:2012-06-30)

参考文献数

6

被引用文献数

2

---

This paper aims at design of network control system for the remote control of robot. As the system includes a communication channel, quantization is required to satisfy communication capacity limitation. Dynamic quantizer is a kind of quantization methods and has been studied in control engineering field. Optimal quantizing width designed of dynamic has been designed based on invariant sets. However, quantizing width of dynamic quantizer designed based on invariant sets has maintainability than one of designed based on reachable sets and big maintainability and poor control performance. We need to design quantizing width of dynamic quantizer based on reachable sets. In this study, we propose design method of quantizing width of dynamic quantizer based on reachable sets. The effectiveness is shown by numerical example.

著者

Hiroshi OKAJIMA Kenji SAWADA Nobutomo MATSUNAGA

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.47, no.2, pp.126-133, 2011 (Released:2011-12-19)

参考文献数

15

被引用文献数

4 2

---

This paper proposes a design method of the dynamic quantizer for the networked control systems. In the networked control systems, the data size of the signals is limited because of the transmission rate of the communication channel. It is well known that feedback type dynamic quantizers such as Delta/Sigma modulator are effective for quantization of data series. The dynamic quantizer includes a set of the dynamic filter and the static quantizer. Many methods have been proposed to design the dynamic filter. However, the static quantizer part has not been designed although the quantization level number of the static quantizer has an effect on the data size. The simultaneous design of dynamic filter and the quantization level will be important issue to satisfy the given communication rate. In this paper, the integrated design method of the filter and the static quantizer is proposed based on the communication rate constraints. The proposed method is derived based on the invariant set analysis with LMIs. The effectiveness is shown by numerical examples.

著者

Hiroshi OKAJIMA Nobutomo MATSUNAGA Kenji SAWADA

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.46, no.6, pp.327-335, 2010 (Released:2011-11-03)

参考文献数

21

被引用文献数

6 3

---

This paper proposes the design method of the dynamic quantizer for the networked control systems. It is well known that feedback type dynamic quantizer such as Delta/Sigma modulator is effective for quantization of data series and many methods for designing the dynamics have been proposed. When it is required to control with network communication, the data size of signal should be minimized appropriately by quantizers. Since the quantizing width of the quantizer concern with the data size, determination of quantizing width is important problem in networked control systems. However, the quantizing width has not been designed analytically in the past researches. In this paper, we propose the design method of the quantizing width based on the LMIs. The quantizing width would be determined explicitly with the communication rate constraints. By the proposed method, the quantizing width guarantee that the signals are quantized appropriately within the given data size. The effectiveness is illustrated by numerical examples.

著者

Takuma WAKASA Kenji SAWADA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)

巻号頁・発行日

vol.E104-A, no.11, pp.1461-1469, 2021-11-01

---

This paper proposes a switched pinning control method with a multi-rating mechanism for vehicle platoons. The platoons are expressed as multi-agent systems consisting of mass-damper systems in which pinning agents receive target velocities from external devices (ex. intelligent traffic signals). We construct model predictive control (MPC) algorithm that switches pinning agents via mixed-integer quadratic programmings (MIQP) problems. The optimization rate is determined according to the convergence rate to the target velocities and the inter-vehicular distances. This multi-rating mechanism can reduce the computational load caused by iterative calculation. Numerical results demonstrate that our method has a reduction effect on the string instability by selecting the pinning agents to minimize errors of the inter-vehicular distances to the target distances.

著者

Katsuhiko SANDO Takeshi YAMAMOTO Kenji SAWADA Tomoyuki TANIGUCHI Nobuyuki SOWA Haruki MORI Takahiro KONDO

出版者

The Japan Society of Mechanical Engineers

雑誌

Mechanical Engineering Journal (ISSN:21879745)

巻号頁・発行日

pp.20-00497, (Released:2021-03-03)

参考文献数

11

被引用文献数

1

---

This paper describes a design method of a friction reducer device using a loading cam to suppress unstable vibration. Nonlinear simulation and energy analysis of numerical solutions demonstrates that destabilization is caused by the large phase difference between the slipping velocity in the translation direction and that in the rotation direction. It was found that similarly unstable vibration occurs in various structures using wedge rollers with translational and rotational motion. The analytical equation could be simplified by focusing on the motion factor that affects the slip velocity of the power transmission surface, which is the factor of vibration. Consequently, the design method for suppressing vibration could be expressed by a mathematical formula. This equation is validated by using the results of experiments conducted in the previous work of the current authors. Furthermore, from this equation, we proposed that vibration could be suppressed by the parameter balance of the power transmission device without using damping. The power transmission surface slips when a quick torque is input and damping is used. The proposed design can handle a quick torque response and reduce the weight of the reducer. Specifically, the shape of the wedge roller is made lighter, so that the moment of inertia of the roller is not lowered, or the wedge roller is set as a small roller.