Browsing by Author "Hsu, Pau-Lo"

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A Boundary Element Application of Plastic Hinges Development in a Circular Ring
(2011)
Young, Lih-jier
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Hsu, Pau-Lo
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Yeh, Syh-Shiuh
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Chang, Yufang
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電控工程研究所
Circular ring is the most popular specimen in industry. The location of a crack in a circular ring can strongly affect the sequence of plastic hinge development which in turn affects stability of a circular ring which has been obtained theoretically in Young [1] but not any numerically. Boundary element method is employed to investigate these effects. In fact, the ring will collapse if the number of plastic hinges is up to four. The results show the potential application of the boundary element method in this project.
Analysis and applications of the motion message estimator for network control systems
(2008-01-01)
Hsieh, Chen-Chou
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
The time-delay effect in network systems is unavoidable because of its limited transmission bandwidth. In real-time network control systems (NCS), all messages are required to be transmitted or received to meet specifications of the deadline. Therefore, the data dropout may thus occur in NCS due to its time delay in a stochastic nature. In this paper, a motion message estimator is proposed to construct a real-time motion NCS to significantly reduce the data-dropout effect. Both simulation and experimental results indicate that a 3rd-order message estimator based on the Taylor expansion can be properly implemented in NCS for industrial motion control systems. Furthermore, since the uncertainties of the NCS estimator are greatly suppressed by applying the message, experimental results indicate that its integration with the feedforward control leads to significantly improved accuracy for the NCS implemented on an industrial computerized numerical control (CNC) machine tool.
Analysis and Implementation of a Model-free Approach in Network-induced Delay Compensation for Remote Control Systems
(2011)
Lai, Chien-Liang
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Hsu, Pau-Lo
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電機工程學系
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Department of Electrical and Computer Engineering
With the rapid development and implementation of Internet technologies, well-designed/tuned controllers obtained from control design without network are desired, which can be further realized in remote control systems directly. Theoretically, available networked control system (NCS) designs are developed with a known system model and time delay. However, the nature of network-induced delay is unpredictable, which depends on network protocol and hardware, and available design approaches usually become impractical in real concerns. The study presents an NCS structure with the proposed perfect delay compensation (PDC) scheme, which is constructed with modified butterfly elements to deal with unknown delay effects without system model and delay information. Both analytical and simulation results prove that the proposed model-free PDC scheme effectively compensates for the unknown network-induced delays. Furthermore, the proposed PDC is carried out using Ethernet, and a well-tuned PI controller for the AC servo motor was directly networked to the remote control system. Experimental results indicate that the proposed PDC renders satisfactory and desirable design results in real NCS applications.
Applications of integrated motion controllers for precise CNC machines
(2009-10-01)
Yeh, Syh-Shiuh
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Tsai, Zheng-Hong
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
The error resources of precise motion control systems are basically categorized into linear and nonlinear effects. To realize the precise motion of industrial computer numerical control (CNC) machines, this paper presents an integrated motion control structure with modular algorithms, including both the linear control and the nonlinear compensation. In the linear control design, this study applies three algorithms: (1) feedforward control to address the tracking errors, (2) cross-coupled control to reduce the contouring errors, and (3) digital disturbance observer to lessen the effects of modeling errors and disturbances in real applications. The results indicate that the linear motion controller achieves greatly improved accuracy in both tracking and contouring by reducing the servo lags and mismatched dynamics of the different axes. However, the adverse effect due to friction still exists and cannot be eliminated by applying the linear motion controller only. This study further integrates the nonlinear compensator and develops friction estimation and compensation rules for CNC machines. The digital signal processors are suitable to implement all the developed linear and nonlinear algorithms, and the present controllers have been successfully applied to industrial CNC machines. Experimental results on a vertical machining center indicate that, under different feed rates, the CNC machine with the integrated motion controller significantly reduces the maximum contouring error by 135% on average.
Applications of the Network Controlled System to the Omni-directional Mobile Robot
(2008)
Lin, Yee-Chang
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Liu, Chun-Wei
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Li, Jian-Lung
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Hsu, Pau-Lo
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電控工程研究所
The network control system (NCS) becomes popular in recent industrial applications. Typical advantages of NCS like low cost, reduction of the assembly wires and installation, and maintenance. The command between DSP and each motor can be controlled by either the centralized structure with a voltage signal or the proposed network distributed structure. hi this paper, the serial interface RS-232 is adopted because of its wide applications and support in both hardware and software. The DSP F2812 controls four servo motors through the RS-232 interface. The kinematics model of the omni-directional mobile robot (ODMR) is also considered and the relation between robot and each axis is decoupled by applying its inverse kinematics. The mobile robot was tested with both at a low speed (30 cm/s) and a high speed (100 cm/s). The sampling time for the centralized control structure is usually faster compared with the NCS structure, A suitable sampling time for the NCS with the applications of the ODMR indicates the balance between the sampling time and system performance in real applications.
Design and simulation of adaptive fuzzy control on the traffic network
(2006)
Liu, Hsing-Han
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
In this paper, the adaptive fuzzy control method [1-4] is adopted to improve the traffic network. To deal with traffic during the rush hours, fuzzy controllers commonly switch signals more frequently according to certain circumstances, but it is not practical for real traffic control. In this paper, the adaptive control is concerned to satisfy real applications. The proposed controller adopts more simplified membership functions than those in Kaur and Konga (1994) [5] through analysis of the waiting length; moreover, the number of applied fuzzy rules is also reduced from 86 to 18. To verify the proposed controller through simulation, the parameter setting interface of the software system VISSIM [6] was used to simulate a real traffic intersection and VisVAP was used to achieve the adaptive signal control logic. Given traffic flows as Light (300Veh./hr), Heavy (1000Veh./hr), and Peak (0 similar to 1200Veh./hr), simulation results indicate that the delay time of the proposed approach is significantly reduced.
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.
Design of the channel allocation procedure of the IEEE 802.11 ad-hoc networks for traffic control systems
(2006)
Lin, Tsung-Han
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Wang, B. C.
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
The multi-agent traffic control system is a popular topic in intelligent transportation systems (ITS). Considering the cost of deploying wired networks in real world, the wireless network is more convenient in implementation and it is also more appropriate to serve as the communication interface in the multi-agent traffic control system. In this paper, we propose a new method called the channel allocation procedure (CAP) and its physical protocol of IEEE 802.11 ad-hoc network is further modified to suit the hopping procedure for each single channel sequentially. By combining both the proposed CAP method and the ad-hoc on-demand distance vector routing (AODV), an effective communication interface for the multi-agent traffic control system can be thus directly established. The CAP method solves the hidden terminal problem which is the main cause of the degradation of network throughput. By evaluating the CAP method using the NCTUns network simulator, results indicate that the throughput of proposed CAP method increases by 75% to 2300% compared with that of the original 802.11 ad-hoc networks.
Design of the Multiple-rate Robust Controller for Wireless Networked Control Systems
(2008)
Lai, Chien-Liang
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
This paper integrates the IEEE 802.11 g ad-hoc wireless network and the control area network (CAN) in the present network control systems (NCS) or wireless-NCS (WNCS). Both the TCP and the CAN protocols are adopted as the communication gateway in a remote control system. 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 paper. Experimental results on an AC 400W servo motor indicate that the communication jam mainly causes the instability due to the induced time delay. In this paper, by applying the adaptive Smith predictor with the switching sampling time, satisfactory control performance of WNCS can be obtained even though the time delay seriously increases. Moreover, the feasibility of the proposed WNCS has been proven through experimental results.
Design the Adaptive Controller for Delta Robots with the Decoupling-Current Servo Motor
(2015-01-01)
Huang, Wei-Sheng
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
To pursue high-speed motion control for robots, applications of servo motors with appropriate controllers may render fast responses with satisfactory precision. However, the current coupling effect on the servo motor control unavoidably downgrades stability and contouring precision as the operation speed increases in practice. This paper proposes a control structure simply by adding a decoupling gain Kc to significantly improve stability of motor control systems under high-speed operations. Simulation results on the joints of a Delta robot indicate that the present decoupling control structure effectively leads to satisfactory performance and precision under high-speed operations.
DESIGN THE HIGH-SPEED MICRO-MOTION CONTROLLER FOR PECK DRILLING WITH THE LUGRE FRICTION MODEL
(2015-01-01)
Huang, Cong-Sheng
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Yeh, Syh-Shiuh
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Hsu, Pau-Lo
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電機工程學系
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Department of Electrical and Computer Engineering
Micro-motion control on the peak drilling, particularly in 3C industry processing, is difficult for the spindle to precisely follow the high-frequency commands, mainly because the repetitive motion distance is very small and it passes through zero velocity frequently to cause serious problems of friction. Experimental results indicate that the axis is nearly unmoved by applying traditional controllers in practice. By applying the static friction compensation constructed under constant-speed operations, results indicate that it is suitable only when the motion command is slowly-varying in a low frequency range. In this paper, the LuGre model is adopted and a systematic approach is proposed to obtain corresponding modeling coefficients. Results indicate that by applying the controller with the LuGre model, the bandwidth of the velocity loop is greatly improved from 394Hz to 663.7Hz, and the position loop is greatly improved from 9.5 Hz to 113.8 Hz. The LuGre model has also been realized on a DYNA 1007 CNC machine to prove its feasibility. Moreover, the tracking error of its peck drilling is improved 67.5% in RMS and the maximum peak error improvement is 72.0%.
Design the Remote Control System With the Time-Delay Estimator and the Adaptive Smith Predictor
(2010-02-01)
Lai, Chien-Liang
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
In real applications, a remote control system is generally an integration of different networks consisting of a commercial network for message transmission and an industrial network to control the remote hardware through a communication gateway. Since the induced time-delay in network control system (NCS) may cause system instability, this paper proposes a remote NCS structure by implementing the adaptive Smith predictor with an online time-delay estimator. As the delay in a commercial network Ethernet is significantly time-varying depending on the number of end-users, the delay is estimated in this paper by processing the online measurement of the round-trip time (RTT) between the application layers of the server and the client. The adaptive Smith predictor control scheme is developed by directly applying the estimated time-delay. To prove the feasibility of the proposed remote control system, the developed design has been applied to an AC 400 W servo motor tested from a 15 km distance. The experimental results indicate that the significantly improved stability and motion accuracy can be reliably achieved by applying the proposed approach.
Development of A Behavior-Based Cooperative Search Strategy for Distributed Autonomous Mobile Robots Using Zigbee Wireless Sensor Network
(2014-03-01)
Shih, Tzu-Chiang
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Yeh, Syh-Shiuh
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Hsu, Pau-Lo
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電機工程學系
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Department of Electrical and Computer Engineering
To achieve efficient and objective search tasks in an unknown environment, a cooperative search strategy for distributed autonomous mobile robots is developed using a behavior-based control framework with individual and group behaviors. The sensing information of each mobile robot activates the individual behaviors to facilitate autonomous search tasks to avoid obstacles. An 802.15.4 ZigBee wireless sensor network then activates the group behaviors that enable cooperative search among the mobile robots. An unknown environment is dynamically divided into several sub-areas according to the locations and sensing data of the autonomous mobile robots. The group behaviors then enable the distributed autonomous mobile robots to scatter and move in the search environment. The developed cooperative search strategy successfully reduces the search time within the test environments by 22.67% (simulation results) and 31.15% (experimental results).
Implementation of a remote hierarchical supervision system using Petri nets and agent technology
(2007-01-01)
Lee, Jin-Shyan
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Hsu, Pau-Lo
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電控工程研究所
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Institute of Electrical and Control Engineering
For remote control systems, certain human operations may violate desired requirements and result in catastrophic failure. For such human-in-the-loop systems, this paper implements a hierarchical supervision system to guarantee that remote human-issued commands meet required specifications. In the presented scheme, Petri nets are applied to model, design, and verify both the local controller and the remote supervisor. Then, the agent technology is adopted to implement the supervisor as an intelligent agent for an online supervision of the remote control system. Hence, undesired resource conflicts and deadlock states can be avoided. An application to a flexible manufacturing system controlled over the Internet is provided to illustrate the developed approach. Implementation results show that by applying the presented hierarchical scheme, the supervisor has a more compact model with fewer states. Moreover, fewer request/response transmissions are consumed so that the effects of time delays and packet losses across the Internet could be moderated.
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.
Multiparadigm modeling for hybrid dynamic systems using a Petri net framework
(2008-03-01)
Lee, Jin-Shyan
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Zhou, MengChu
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Hsu, Pau-Lo
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電機資訊學士班
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Undergraduate Honors Program of Electrical Engineering and Computer Science
Recently, modeling and simulation of hybrid dynamic systems (HDSs) have attracted much attention. However, since simultaneously dealing with the discrete and continuous variables is very difficult, most of the models result in a unified but more complicated and unnatural format. Moreover, design engineers cannot be allowed to use their preferred domain models. Based on the multiparadigm modeling concept, this correspondence proposes a Petri net framework with associated state equations to model the HDSs. In the presented approach, modeling schemes of the hybrid systems are separated but combined in a hierarchical way through specified interfaces. Designers can still work in their familiar domain-specific modeling paradigms, and the heterogeneity is hidden when composing large systems. An application to a rapid thermal process in semiconductor manufacturing is provided to demonstrate the practicability of the developed approach.
Particle filter design for mobile robot localization based on received signal strength indicator
(2016-11)
Hsu, Cheng-Chung
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Yeh, Syh-Shiuh
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Hsu, Pau-Lo
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電機工程學系
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Department of Electrical and Computer Engineering
This paper presents a particle filter design to improve the accuracy of received signal strength indicator (RSSI)-based localization algorithms for localizing mobile robots that move in an environment with an 802.15.4 ZigBee wireless sensor network. In this study, the RSSI of transmission signals is adopted to estimate the location of a mobile robot by applying the trilateration algorithm. However, the interference and reflection effects of transmission signals and the orientation effects of the antenna can significantly affect the RSSI signals and result in serious localization errors. This study analyses the characteristics of RSSI signals and the orientation effects of the antenna and then develops a particle filter design with the fusion of the current states of the mobile robot to improve localization accuracy. A static localization experiment shows that the developed localization algorithm can significantly improve the localization accuracy, and a maximum rate of improvement of up to 85% is achieved in the test environment. A dynamic localization experiment demonstrates that the developed algorithm is suitable for localizing a mobile robot.
Precision Control and Compensation of Servomotors and Machine Tools via the Disturbance Observer
(2010-01-01)
Huang, Wei-Sheng
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Liu, Chun-Wei
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Hsu, Pau-Lo
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Yeh, Syh-Shiuh
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電控工程研究所
The computerized numerical control machine tool is a highly integrated mechatronic system in manufacturing processes. However, uncertainties degrade its motion accuracy. These include modeling errors, parameter variation, friction, and measurement errors that are present in either linear or nonlinear nature. In this paper, a state-space disturbance observer was successfully applied to servomotors to estimate and compensate for the uncertainties of parameter variation and current measurement problems, in the velocity and current loops, respectively. Furthermore, an autotuning procedure was developed accordingly to identify the varied parameters of the motor. Furthermore, by implementing the present servomotor systems in high-precision machine tools, the nonlinear friction compensation was adopted to reduce the slip-stick effect in contouring motion. Experimental results indicate that the roundness error has been significantly reduced from 13.3 to 2.0 mu m by applying the proposed approaches.
Realization of Networked Control Systems on Ethernet with Varied Time Delay
(2010)
Lai, Chien-Liang
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Hsu, Pau-Lo
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電機工程學系
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Department of Electrical and Computer Engineering
An online delay estimation algorithm is adopted for the adaptive Smith predictor in the networked control systems (NCS) design under the significant delay time. However, the Smith predictor is sensitive to parameter uncertainties within the system model and time delay. The quantitative feedback theory (QFT) controller is suitable to cope with parameter uncertainties of the Smith predictor in this paper; moreover, a template expressed in phase and gain for the QFT design has been constructed by considering the bounded variations with the time delay and the external loading. Therefore, the adaptive Smith predictor control scheme with QFT controller provides better tolerance to parameter uncertainties. Both simulation and experimental results on AC servo motor with both the hybrid controller area network (CAN) bus and the Ethernet network have proven the feasibility and improved performance of the proposed NCS.
Remote Control Realization of Distributed Rescue Robots via the Wireless Network
(2008-01-01)
Yeh, Syh-Shiuh
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Hsu, Cheng-Chung
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Shih, Tzu-Chiang
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Hsiao, Jen-Pin
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Hsu, Pau-Lo
Applications of wireless sensor network (WSN) have been widely developed recently. This paper represents distributed rescue robots applying the techniques of WSN to achieve remote control and monitoring through different sensing devices by integrating the ZigBee and 802.11g. The communication channel between the rescued target and the remote host for transmitting video and voice signals through the 802.11g is established for further motion detection to effectively discover victims.