Browsing by Author "Wang, Bor-Chyun"

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Design of the Adaptive Smith Predictor for the Time-Varying Network Control System
(2008)
Lai, Chien-Liang
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Hsu, Pau-Lo
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Wang, Bor-Chyun
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電控工程研究所
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Institute of Electrical and Control Engineering
Ibis paper integrates Ethernet and control area network (CAN) with the TCP/IP communication gateway. The developed system has been applied to a remote control system for an AC 400W servo motor to verify the proposed adaptive Smith Predictor control method with the time-delay estimation algorithm. The time delay effect, defined as the round-trip time (1117), between the application layer of the server and the application layer of the client, has been measured and analyzed. Moreover, results indicate that NCS performance is degraded, and may even become unstable mainly due to the serious network time delay in a stochastic nature mainly occurred in the Ethernet. The Smith predictor is adopted to eliminate the constant time delay. However, the delay in a commercial network is time varying and it depends on the number of end users. An adaptive Smith predictor control scheme is developed in this paper by applying the on-line estimation to further improve control performance of the proposed NCS with the integrated Ethernet and CAN buses. Experimental results indicate that the time delay is drifting in both bounded and random natures for the integrated Ethernet+CAN network and the proposed control approach significantly improves motion accuracy as in the NCS for an AC motor-based motion system.
Implementation of autonomous vehicles with the Hough transform and fuzzy control
(2007)
Tsai, Yu-Kuen
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Han, Lin-Yi
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Hsu, Pau-Lo
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Wang, Bor-Chyun
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電控工程研究所
An automatic driving system for a golf car is developed and tested in the campus. The system utilizes a single vision sensor CCD and adopts the road-model-matching method to obtain the lane marks by applying the Hough transform method. Compared with the inverse perspective mapping (IPM) method of which is affected greatly by the position, yaw and tilt angle of the camera [1] with heavy computation, the present method directly detects the lane marks without including information of the camera. Besides, the present method can be applied to detect curved lane marks simply by using a 2(rd)-order road model. Moreover, in the control for the nonholonomic vehicle, the commonly used PID control is not suitable for the automatic driving system. This paper proposes two different fuzzy logic controllers (FLCs) with nine and fifteen rules, respectively, to achieve the autonomous driving performance satisfactorily.
The motion message estimator in real-time network control systems
(2006)
Hsieh, Chen-Chou
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Hsu, Pau-Lo
;
Wang, Bor-Chyun
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電控工程研究所
;
Institute of Electrical and Control Engineering
In network systems, the time-delay effect is unavoidable and it usually degrades system performance. Furthermore, in the real-time network control system (NCS), messages are required to be transmitted on time to meet specifications of the deadline. Otherwise, it leads to data dropout which occurs randomly in real-time NCS control. The data dropout not only degrades performance of the NCS but also causes the NCS to be unstable. In this paper, a second-order motion message estimator is proposed to compensate for the missing messages containing motion commands and measurements, since most motion systems can be described suitably by second-order Newtonian motion law. The dropout rate of the controller area network (CAN) bus has been evaluated in different transmission rate in this paper. The proposed NCS with the message estimator has been successfully implemented on a CNC machine to achieve significantly improved motion accuracy.
The SDQ-based Message Estimator for Motion NCS
(2009)
Hsieh, Chen-Chou
;
Hsu, Pau-Lo
;
Wang, Bor-Chyun
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The limitation of network bandwidth leads to data dropout of communication which degrades performance of NCS. For motion control system implemented with NCS, the missing interpolation messages will cause motion error and it can be compensated by applying the message estimator. However, the distribution of the missing data will be more relevant to motion accuracy in NCS even with the same dropout rate. This paper proposes a novel performance index, the short-window dropout quantities (SDQ) which is an estimation of both the data dropout rate and the messing message distribution, for the motion NCS. Furthermore, based on the estimation of SDQ. the intelligent motion message estimator (IMM) is proposed in this paper to effectively compensate for data dropout effect. Finally, simulation results of a multi-axis motion NCS indicate that the present IMM significantly improves motion contouring accuracy compared with the 1-delay estimator or the Taylor estimator.
The time-delay effect of multiple-network systems in NCS
(2007)
Cheng, Ching-Wen
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Lai, Chien-Liang
;
Wang, Bor-Chyun
;
Hsu, Pau-Lo
;
電子工程學系及電子研究所
Applications of the network control system (NCS) improve the efficiency, the flexibility, and the reliability of large-scale systems in modem industries. In the same time, applications of NCS for remote control and monitoring reduce the time and cost of installation, reconfiguration, and maintenance. This study integrates the Ethernet, the control area network (CAN) network, and the wireless 802.11b in the present NCS. The TCP/IP and the CAN protocols are adopted as the communication gateway in a remote control system for an AC 400W servo motor. The time delay between the application layer of the client and the application layer of the remote control target has been measured and analyzed in this study. Experimental results indicate that different sampling rates and the environments will greatly affect the delayed time. Also, results indicate that the distance will not affect the delay time in wireless communication. However, as the sampling period reduces, the delay time of the network increases dramatically. In the wireless network, the delay time may change suddenly by the environment interferences. Finally, with a serious time delay, a Smith predictor has been successfully applied to control the servo motor from Kaohsiung which is in 300 kin away to verify the feasibility of the proposed NCS.