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Lin Y.-C.,Precision Machinery Research and Development Center | Chen C.-H.,National Taiwan University of Science and Technology | Chen L.-Y.,National Taiwan University of Science and Technology | Hsu S.-C.,Tamkang University | Qian S.,Old Dominion University
RSC Advances | Year: 2014

In this study, polyvinyl alcohol/nitrogen (PVA/N) hybrid thin films doped with sharp-sword ZnO nanowires with insulating effect and wide-range spectrum are demonstrated for the first time. PVA/N doped ZnO nanocomposites were developed by blending PVA and N-doped ZnO nanowires in water at room temperature. Measurements from the field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman, and photoluminescence emission (PL) spectra of the products show that nitrogen is successfully doped into the ZnO wurtzite crystal lattice. In addition, the refractive index of PVA/N doped ZnO hybrid thin films can be controlled by varying the doped ZnO nanowires under different NH3concentrations. It is believed that PVA/N doped ZnO hybrid thin films are a suitable candidate for emerging applications like heat-shielding coatings on smart windows. This journal is © the Partner Organisations 2014.

Wu Y.,National Chin - Yi University of Technology | Li S.,National Chin - Yi University of Technology | Chuang W.,Precision Machinery Research and Development Center
Advanced Science Letters | Year: 2013

Focusing on the effects of design and operating parameters of the stirring system in the reactor processing equipment including blade deflection angle, blade number, stirring rotation speed and reactor chamber volume size on the reactor stirring flow field homogeneity, this study mainly conducts the simulation analysis of the velocity field, turbulence intensity and concentration field inside the reactor chamber in case of different parameter combinations by using the computational fluid dynamics (CFD) simulation analysis technology. This study also employs the Taguchi method (design of experiment) to conduct parameter optimization analysis and discuss the weights of effects o arious parameters on reactor homogeneous flow field in accordance with simulation results. The proposed me be applied for rapid and effective discussions on concentration stirring in case of different reactor chamber volume structure design and blade type. In particular, when the procedure is changed in the future, the optimal reactor design can be obtained quickly and be used to predict the entire stirring procedure and thermal flow field homogeneity in advance. 2013 American Scientific Publishers All rights reserved.

Sung C.K.,National Tsing Hua University | Lu C.H.,National Tsing Hua University | Chan T.C.,Precision Machinery Research and Development Center
19th International Congress on Sound and Vibration 2012, ICSV 2012 | Year: 2012

This study evaluated the influence of external excitations on ball positioning in an automatic ball balancer (ABB) installed in a rotor system. The authors' previous studies adopted a model that considered the ABB as an autonomous system by neglecting external excitations. However, the ABB may be employed in various rotor systems where the external excitations, for example, caused by cutting and floor vibrations, may not be avoidable. Herein, we examined how the magnitude, the frequency and even the phase of an external excitation affected ball positioning. The equations governing the motions of the rotor system and the balancing balls were derived first. Then, simulations were performed to predict the ball positions under various external forces. Finally, we constructed an experimental rig by employing a shaker to apply excitations to the rotor system and the associated ABB to verify the theoretical development. Simulation results indicated that the balancing balls of the ABB could counterbalance the external force by changing the ball positions. However, it was observed from the experiment that the ball would not be displaced if the external force was applied after the ball had been positioned because the excessive rolling resistance between the ball and the race prevented the ball from motion. This may further deteriorate the balancing performance and cause larger undesired residual vibrations.

Hwang K.-S.,National Sun Yat - sen University | Jiang W.-C.,National Chung Cheng University | Chen Y.-J.,National Chung Cheng University | Wang W.-H.,Precision Machinery Research and Development Center
Proceedings - 2013 IEEE International Conference on Systems, Man, and Cybernetics, SMC 2013 | Year: 2013

In this paper, a model learning method based on tree structures is present to achieve the sample efficiency in stochastic environment. The proposed method is composed of Q-Learning algorithm to form a Dyna agent that can used to speed up learning. The Q-Learning is used to learn the policy, and the proposed method is for model learning. The model builds the environment model and simulates the virtual experience. The virtual experience can decrease the interaction between the agent and the environment and make the agent perform value iterations quickly. Thus, the proposed agent has additional experience for updating the policy. The simulation task, a mobile robot in a maze, is introduced to compare the methods, QLearning, Dyna-Q and the proposed method. The result of simulation confirms the proposed method that can achieve the goal of sample efficiency. © 2013 IEEE.

Chou H.-C.,National Taiwan University of Science and Technology | Chung J.-C.,National Taiwan University of Science and Technology | Kuo C.-H.,National Taiwan University of Science and Technology | Chou B.-Y.,Precision Machinery Research and Development Center
Proceedings of the World Congress on Intelligent Control and Automation (WCICA) | Year: 2011

In this paper, a kid size humanoid robot, HuroEvolution, is presented. The HuroEvolution is developed for two autonomous robot competitions of RoboCup 2010 and FIRA 2010. In order to perform various competition functions, the robot structure, sensor modules, control systems and software programs are designed to meet the competition requirements of participated games. In addition to the brief introductions of the mechanical structure, sensor modules and control system, this paper focuses on the illustrations of autonomy for various skill-oriented functions. Our solutions are developed based on autonomous sensing and decision approaches. The autonomous sensing approach is realized in terms of typical sensor fusion techniques, which combine the information collected from a web camera and a 3-axis magneto-resistive sensor. The fused sensor information is further used for skill-oriented autonomous decision systems which are responsible of navigations and task executions. Currently, the HuroEvolution is capable of playing the games of soccer, weightlifting, obstacle run, sprint, marathon and basketball. Finally, the proposed skill-oriented functions were verified in the RoboCup 2010 and FIRA 2010 competitions. © 2011 IEEE.

Hwang K.-S.,National Sun Yat - sen University | Li J.-S.,National Sun Yat - sen University | Jiang W.-C.,National Chung Cheng University | Wang W.-H.,Precision Machinery Research and Development Center
Proceedings of the SICE Annual Conference | Year: 2013

The study on biped walking control using reinforcement learning is presented in this paper. The Q-learning algorithm makes a robot learn to walk without any previous knowledge of dynamics model. The research topic is mainly focused on how the robot keeps balance with one leg. This balance control way that utilized the motion of robot arm and leg to transfer the Zero Moment Point (ZMP) of the robot would maintain the ZMP in a stable state. Hence, the proposed method which integrated this balanced algorithm with the balance control way applied on biped walking on the plain or seesaw, it makes the biped walk more stable. Finally, there are several simulations that demonstrate the feasibility and effectiveness of the proposed learning scheme.

Hwang K.S.,National Sun Yat - sen University | Ling J.L.,Shih Hsin University | Chen Y.-Y.,National Chung Cheng University | Wang W.-H.,Precision Machinery Research and Development Center
Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics | Year: 2014

In this paper, a non-expert learning system was proposed to guide the robots learn their behaviors by humans' emotional expressions. The proposed system used interval fuzzy type-2 algorithm to recognize the human's facial expressions, which were captured by a web camera. Furthermore, emotion value (E-value), generated based on non-expert human's facial expressions, was applied to the reinforcement learning to train robots. Two kinds of problems were experimented. One was the human being know the exact solution to train robots and could clearly observe good or bad choice robots had been made. The other one was human being did not know the exact solution but robots could still learn from human's experience. The experiment results show that no matter the learning environment could be clearly observed by human being or not, robots could learn from human's facial expressions by the proposed learning system. © 2014 IEEE.

Yu S.-H.,National Sun Yat - sen University | Hsieh Y.-F.,National Sun Yat - sen University | Lai P.-Y.,National Sun Yat - sen University | Chen Y.-L.,National Sun Yat - sen University | And 2 more authors.
International Conference on Applied Electronics | Year: 2015

An FPGA-based class-D power amplifier is designed for driving an ultrasonic transducer. The amplifier is capable of automatically detecting and tracking the transducer's resonant frequency, driving the transducer right at its resonance for maximizing vibration efficiency. The design focuses on devising resonant frequency tracking and optimal modulation algorithms that are suitable for FPGA implementation. © 2015 University of West Bohemia.

Hwang K.S.,National Sun Yat - sen University | Ling J.L.,Shih Hsin University | Wang W.-H.,Precision Machinery Research and Development Center
IEEE International Conference on Automation Science and Engineering | Year: 2014

In this paper, an adaptive state aggregation Q-Learning method, with the capability of multi-agent cooperation, was proposed to enhance the efficiency of reinforcement learning (RL) and applied to box-pushing tasks for humanoid robots. First, a decision tree was applied to partition the state space according to temporary differences in reinforcement learning, so that a real valued action domain could be represented by a discrete space. Furthermore, adaptive state Q-Learning, which is the modification of estimating Q-value by tabular or function approximation, was proposed to demonstrate the efficiency of reinforcement learning when a humanoid robot pushing a box was simulated. During the process of a robot pushing a box, because the box moves along with the direction the robot asserts force and the pushing point on the box, the robot needs to learn how to adjust angles, avoid obstacles, keep gravity, and push the box to the target point. From the simulation results, the proposed method shows its learning efficiency outperforms the Q-Learning without using adaptive states. © 2014 IEEE.

Wang D.-A.,National Chung Hsing University | Chuang W.-Y.,Precision Machinery Research and Development Center | Hsu K.,Precision Machinery Research and Development Center | Pham H.-T.,National Chung Hsing University
Ultrasonics | Year: 2011

A new horn for high displacement amplification is developed. The profile of the horn is a cubic Bézier curve. The ultrasonic actuation of the horn exploits the first longitudinal displacement mode of the horn. A design method of the horn using an optimization scheme and finite element analyses is developed. Prototypes of the horns are manufactured by a numerical control machining process. Performances of the proposed horn have been evaluated by experiments. Experimental results of the harmonic response of the fabricated horn confirm the effectiveness of the design method. The displacement amplification of the proposed horn is 71% higher than that of the traditional catenoidal horn with the same length and end surface diameters. © 2010 Elsevier B.V. All rights reserved.

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