Browsing by Author "Yeh, Syh-Shiuh"

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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.
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.
Cutting Force Monitoring and Control System for CNC Lathe Machines
(2016)
Cubas, Jorge
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Leoro, Josuet
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Reyes, Daniel
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Yeh, Syh-Shiuh
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電機資訊國際碩士學位學程
The importance of cutting forces during turning processes creates the need for a simple and low-cost solution to measure those forces. Various improvements on the cutting performance can be achieved by using these measurements. The present study explains the design and construction of a cutting force sensor, as well as the implementation of a fuzzy logic controller to obtain a complete system to monitor and control the cutting forces in rough turning operations. The force sensor uses four strain gauges attached on the sides of the tool holder to estimate the cutting forces. The force controller is designed to smoothly adjust the feed rate because a fast change in the feed rate could damage the cutting tool. The maximum cutting force needs to be input manually in this approach, because it will be the reference variable for the fuzzy controller. The maximum force is selected by the operator based on tool conditions, tool temperature, machining conditions, workpiece material, tool material, etc. A balance between the speed required to achieve the reference force and the smooth feed rate change is considered. The simulation results obtained by controlling the cutting force along with the associated machining time improvements are presented in this paper.
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%.
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).
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.
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.
T-S fuzzy path controller design for the omnidirectional mobile robot
(2006)
Shing, Chong-Cheng
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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
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Institute of Electrical and Control Engineering
This paper focuses on the design of T-S fuzzy path controller for improving the high-speed tracking accuracy of a four-wheel omnidirectional mobile robot (ODMR). Usually, when an ODMR moves in high speed, the adverse effects induced by Coriolis force significantly deteriorate the tracking performances. In this paper, a T-S fuzzy control designed with both the state feedback and path tracking error is proposed to meet the design specifications. Moreover, a new approach of kinematics inversion considering the nonlinear term of coordinate transform is proposed to simplify the analysis of ODMR motion. Finally, an example is provided to compare the present T-S fuzzy path controller with the well-tuned PID controller. The simulation results indicate that the proposed approach provides much better tracking performances as the speed of ODMR increases.
TARGET POSITION ESTIMATION USING MULTI-VISION SYSTEM IMPLEMENTED ON DISTRIBUTED MOBILE ROBOTS
(2013)
Hsiao, Jen-Pin
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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
In this study, a multi-vision system implemented on distributed mobile robots to estimate the target position of an object in the real world was developed. A triangulation method using the colour feature of an object was applied to develop the target position estimation method. The geometrical relationship among mobile robots affects the accuracy of target position estimation; thus, the effects induced by the geometrical relationship were analysed and a fusion method to obtain accurate estimation results was developed. Moreover, a video stabilization method that integrates the block matching method, weighs averaging method, and the Kalman filter design was developed to provide stabilized images to improve the target position estimation accuracy when the distributed mobile robots move on an uneven ground. A method for detecting and eliminating incorrect estimations was further developed to reduce the adverse effects induced by ill-conditioned image quality. Finally, an application related to the cooperative motions of multiple mobile robots demonstrated the feasibility of the multi-vision system and the approaches developed in this study using image- and position-visual servoing techniques.