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Development of An Intelligent Traffic Light for Reducing Traffic Accidents
Katsuya Matsuzaki,Masuhiro Nitta,Kiyotaka Kato 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
Increase of a traffic accident is recognized as a social problem, hence reduction of he accidents now becomes an urgent task. This paper places a special emphasis on saving pedestrians at blind intersections because the death rate of the pedestrian at the blind intersection is high. To prevent the accident, the paper proposes a notion of the intelligent traffic light. In case that a car and a human are in danger of collision at the intersection, the intelligent traffic light makes the corresponding car stop autonomously by transmitting a warning signal. In order to demonstrate the effectiveness of the proposed traffic system, we substituted a mobile robot for a car. As for the intersection, we installed a radio transmitter with a car approaching sensor and a human detection sensor. As for the mobile robot, we installed a radio receiver and a car control unit. Experimental results indicated that the mobile robot stopped autonomously before the collision and pedestrians would not be injured. But the mobile robot stopped suddenly because the present system did not pay mind to the safety of drivers. This paper thus considers the deceleration curve so that cars stop smoothly. As the result of experiments, the proposed system is applicable enough to the real environment.
New Controller Design Method Based on the Data Conversion Method
Ryota Arimura,Chinthaka Premachandra,Kiyotaka Kato 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10
For targeting a feedback system with an unknown plant (controlled object), there are several methods for controller designing. In order to reduce costs, conventional methods use a single set of experimental I/O data to design a controller. In this paper, we propose a new method for this purpose, which improves the conventional data conversion method (DCM) and enables us to design a controller by giving an outline figure of the ideal output. In the proposed method, two kinds of the I/O data of the plant are defined. One data is obtained from the linearity of the plant, experimental data (single set of I/O), and an unknown vector. The other is obtained from the structure of a feedback system when the ideal output is given. A controller is designed by matching these two data. Because designing with giving the ideal output directly is possible, this method provides a design environment that makes it possible to reflect a user’s idea. Furthermore, proposed method produces a more appropriate parameter for the controller. We confirmed the effectiveness of new method by conducting simulation experiments. In the experiments, we compared proposed method with conventional DCM, and designed a controller by assuming the outline of the ideal output. The result of proposed method showed better performances compared to the conventional methods.
Shotaro Sato,Chinthaka Premacandra,Kiyotaka Kato 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10
It is important for an autonomous flying robot to be able to estimate self-position and attitude. However, GPS cannot be used because of the accuracy problem indoors. This paper proposes a measurement system using the positional relation between an ultrasonic transmitter placed on the ground and an ultrasonic receiver mounted on a flying robot. Moreover, the system applies an estimator using an Extended Kalman Filter (EKF) in order to improve the measurement accuracy. The state variable consists of the position vector and attitude vectors. In applying the EKF, a system model is formulated theoretically assuming that the measured distance data are random variables with uniform distribution. Theoretical derivation reveals that the variance calculation becomes very complicated. The simulation experiment demonstrates the propriety of the theory. In addition, the design of a prototype board and the implementation problem with the hardware are discussed.
Error Analysis on Distribution-based Frequency Estimator
Asami Ishizaka,Masuhiro Nitta,Kiyotaka Kato 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
Frequency estimation is a useful technology for analyzing oscillatory phenomena. In these days, there is a demand for rapid and highly accurate frequency estimator. Though various frequency estimation methods have been proposed, most of them can not respond to the demand. An algebraic approach is succeeded in achieving the demand but it requires a lot of multiple integrations due to eliminating differential operations. The present paper proposes a frequency estimator of a sinusoidal signal based on the notion of distribution theory. Then the estimator is realized by single integrations. The proposed method relaxes the complexity of multiple integrations into single integrations but the integration is theoretically evaluated over the infinite interval (-∞,∞). The paper firstly reduces the infinite interval to a finite observation interval [0,T] and secondly approximates the integration by a numerical integration. The authors introduce Gaussian function as a test function and perform an error analysis to ensure the accuracy of the frequency estimator. As a result of the error analysis, the suitable conditions of the Gaussian function are clarified. Under the derived conditions, the authors confirmed that the proposed frequency estimator brings out enough the estimation performance.
Pseudo-Real-Time Control of a USB I/O Device under Windows 7
Yuto Watanabe,Akiyoshi Yamada,Masuhiro Nitta,Kiyotaka Kato 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
Windows-based PCs (Personal Computers) provide a powerful development environment for controller synthesis because it is easy to evaluate the control effect via installed multifunction I/O devices. These I/O devices are expensive due to handling a real-time processing while non-real-time I/O devices are constructed by inexpensive general-purpose ICs (Integrated Circuits.) The aim of this paper is to assemble an inexpensive I/O device with USB interface and to realize a software-based real-time processing. Since Windows does not allow application programs to access such devices, device drivers are required certainly. Device driver should be coded by fulfilling the device drivers’ specification but it is so costly for beginners. The present paper relaxes the development cost by employing the KMDF (Kernel-Mode Driver Framework.) Then the authors develop an application program to command the I/O device periodically. In order to measure the elapsed time precisely, the paper utilizes the RDTSC (Read Time Stamp Counter) instruction. The authors tackle the stabilization problem of the rotational inverted pendulum to evaluate the usefulness of the developed system.
Development of an Adaptive Cruise Control System Using a Monocular Camera
Yuto Baba,Yuto Watanabe,Masuhiro Nitta,Kiyotaka Kato 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
ACC (Adaptive Cruise Control) system has been attracted much attention because it has a potential to reduce traffic accidents and drivers’ stress. The system maintains a safe inter-vehicular distance and assists driving by keeping traffic lane automatically. Though the conventional ACC system can observe the preceding vehicles using a millimeter wave radar, it fails in following in case of a curved road because of the narrow detection angle. The present paper develops an ACC system to maintain the safe distance by using a monocular camera even though the tracking course is curved. The inter-vehicular distance and the steering angle is calculated by image processing of the acquired video image. By using the processed data, the proposed ACC system properly controls the vehicle velocity and the steering angle. The effectiveness of the proposed system has been evaluated through experiments using mobile robots instead of real cars. The experimental results reveal that the proposed system surely maintains the inter-vehicular distance to the preceding mobile robot.
Design of Two Degree of Freedom Controller Using Data Conversion Method
Shota Higuchi,Ryota Arimura,Chinthaka Premachandra,Kiyotaka Kato 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10
Several data-driven design methods for a feedback controller for an unknown plant were studied. The data conversion method (DCM), which is one of the methods, has improved the design ability for more various plants by using a new approach. This paper applies the revised DCM to a two degree of freedom controller. First, the paper discusses a theory when applying DCM to a two degree of freedom controller. Then, it discusses the application of DCM to three structures of two degree of freedom controllers. Several experiments show that a controller can be directly designed from outline waveforms to a two degree of freedom controller. As a result, the paper shows that DCM is a convenient method for designing a two degree of freedom controller compared to conventional methods.
Absolute positioning control of indoor flying robot using ultrasonic waves and verification system
Fumiya Sato,Yuta Motomura,Chinthaka Premachandra,Kiyotaka Kato 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10
Currently, absolute positioning methods for indoor flying robots use multiple cameras to measure position through image processing. However, such systems are large scale and costly. Therefore, we have developed a measurement and control system that uses ultrasonic waves. The system consists of a ground base with three ultrasonic transmitter units and a flying robot. The flying robot is equipped with onboard measurement and control devices. This system is small and inexpensive. This paper reports on a verification system that proved the effectiveness of the proposed system. The verification system resulted in improvements to the measurement and control devices. Then, the system realized autonomous flight using ultrasonic waves. This paper describes the details of the method for using ultrasonic waves to control the positioning of an indoor flying robot, the newly developed hardware and software that enable the autonomous flight, and the results of a flight experiment.