Jui-Hong Horng

Neural adaptive tracking control of a DC motor

Abstract This paper presents a neural network-based adaptive control strategy for speed or position tracking of a DC motor with unknown system nonlinearities. In the proposed scheme, we successfully integrate some existing techniques, such as the input–output linearization technique used to cancel the nonlinearities, and neural networks used to implement the linearizing control law. The network approximation errors are compensated by using the sliding mode control scheme. Moreover, the neural network parameters are updated according to the Lyapunov approach. It is shown that, through the proposed control scheme, the rotor speed or position of a DC motor can follow any arbitrarily selected trajectories under variable load torque. Numerical simulation results are provided to confirm the performance and effectiveness of the proposed control approach.

Quality optimization of liquid phase deposition SiO2 films on gallium arsenide

Abstract For liquid phase deposition (LPD) at room temperature (∼40°C) of silicon dioxide (SiO 2 ) on gallium arsenide (GaAs) substrate, this study correlates growth solution concentrations with resultant film quality. This LPD process pretreats the GaAs substrate with ammonia solution kept at pH=11–12, thereby generating OH radicals on the GaAs surface which enhance SiO 2 deposition. It is found that growth conditions such as low hydrofluosilic acid concentration, proper boric acid concentration, and low growth rate play important roles in optimizing deposited film quality. When LPD-SiO 2 /GaAs grown at optimum conditions is used to fabricate a metal-oxide-semiconductor field effect transistor, the transconductance, g m , is about 68, the drain current, I DS , is 10 mA for gate oxide thickness=20 nm and W / L =40/2. LPD-SiO 2 /GaAs grown at the proposed conditions equals or exceeds the quality of competing techniques, with a process that proceeds rapidly at room temperature and pressure, with inexpensive equipment.

Hybrid MATLAB and LabVIEW with neural network to implement a SCADA system of AC servo motor

The AC servo motor system is a non-linear system with uncertainty of parameters. Therefore, it is not easy to identify the system with traditional mathematical model. In this paper, there are four algorithms, that is, SDBP, MOBP, VLBP and LMBP of back-propagation network are trained, and choose better one to identify the system. The method of designing controller is easy and can be applied conveniently in engineering. Simulation results show that LMBP has more fast convergence and it is suitable for system identification and controller design. In the proposed scheme, we successfully integrate MATLAB/Simulink and LabVIEW with neural network to develop a SCADA system of AC servo motor. Numerical simulation results are provided to confirm the performance and effectiveness of the proposed control approach.

SCADA system of DC motor with implementation of fuzzy logic controller on neural network

In this paper, a supervisory control and data acquisition system of DC motor with implementation of fuzzy logic controller (FLC) on neural network (NN) is presented. We successfully avoid complex data processing of fuzzy logic in the proposed scheme. After designed a FLC for controlling the motor speed, a NN is trained to learn the input-output relationship of FLC. The tasks of sampling and acquiring the input signals, process of the input data, and output of the voltage are commanded by using LabV1EW. Finally, the experimental results are provided to confirm the performance and effectiveness of the proposed control approach.

A compact slot UWB antenna with CPW-fed

A simple and novel compact CPW-fed slot antenna which has small dimension of (25 times14 mm2) is proposed for Ultra-Wideband applications. The special is inner antenna which also has smaller dimension of (7 times 5 mm2). To miniaturize the antenna size, the accessional ground planes and staircase shape antenna are introduced. The proposed planar coplanar waveguide fed antenna is easy to be integrated with radio-frequency /microwave circuitry for low manufacturing cost. The optimal dimensions can be achieved by a parametric analysis. The designed antenna operates over 3.0 to 10.9 GHz for VSWRles2. The antenna also shows omnidirectional radiation patterns and that is suitable for UWB applications.

Compact five-band meandered PIFA by using meandered slots structure

The development of small integrated antennas plays a significant role in the progress of rapidly expanding wireless communication applications. The proposed planar inverted-F antenna is designed for multi-bands operation by using three meandered slots etched in the meandered patch pattern. The novel meandered antenna is able to operate in the GSM-900/GPS-1575/DCS-1800/PCS-1900/WLAN bands with a voltage standing wave radio (VSWR) better than 2.5. Modifying the three meandered slots structure of antenna is alternative way to obtain the desired multi-bands resonance frequency operation and reduce 50% of the conventional meandered antenna size. The compact multi-bands method is attractive from the point of view of practical antenna performances.

Improved Extraction Efficiency of Light-Emitting Diodes by Wet-Etching Modifying AZO Surface Roughness

In this letter, the AlGaInP light-emitting diodes (LEDs) between the air and GaP layer are added to the textured ZnO:Al (AZO) films in order to improve light extraction of the device. At 20 mA, the relative luminous intensity of textured AZO LEDs is increased by 129.9% when compared with the conventional sample. Furthermore, the far-field radiation pattern was improved with intensity not only at 0° , but also from 60° to 300° . Due to loss of internal Fresnel efficiency and critical angle efficiency, textured AZO LEDs are significantly improved by the wet-etching technique. The surface treatment of AZO films generates surface texturing that is characterized as random crater. It presents a better far-field radiation pattern when compared with nontextured AZO films. This letter has demonstrated the far-field radiation pattern and the theory for enhancing light emission efficiency of LEDs.

A Novel Microwave Microstrip Surface Acoustic Wave Filter with Gigahertz Band Low-Loss Wide Bandwidth for Broad Spectrum Communication System

A novel GHz-band low-loss wide bandwidth microwave microstrip, surface acoustic wave (SAW) filter used for the spread spectrum communication system has been designed and fabricated. The 16-µm-input/output-interdigital-transducer (IDT) LiNbO3 61.00-MHz-SAW filter with microwave square open-loop resonators has an insertion loss of 3.987 dB. This device is also a 1 GHz microwave microstrip SAW filter with four coupled microstrip square open-loop resonators and two planar interdigital capacitors with S21 and S11, having bandwidths of -2.962 dB and -25.497 dB, respectively, and 800 MHz. It is speculated that the characteristics of these low-loss wide bandwidth (BW=80%) microstrip SAW filters are influenced by the interaction between electromagnetic wave and piezoelectric SAW. To confirm this speculation, devices with the same design have been fabricated on 128°-rotated YX-cut LiNbO3,GaAs S-I and 9000 A SiO2/Si substrates. Significant variations of performance are observed among these devices.

Direct bonding of recessed-structure SAW filter on silicon substrate

A procedure for fabricating a recessed surface acoustic wave (SAW) device coupled with silicon substrate is reported. The recessed structure is stable and rugged enough against the bonding process, and it can be applied to integrate a semiconductor device into one chip by a direct bonding technique. In this paper, the tensile strength of silicon (Si)-to-recessed-SAW filter is measured, and the performance of the device is discussed.

Adaptive-neural control of a class of unknown nonlinear discrete-time systems

An adaptive controller based on neural networks is derived for controlling a class of unknown nonlinear discrete-time systems. The learning algorithm, Widrow-Hoff delta rule, is used to minimize the error signal. It is proved that the control objective is achieved by the closed-loop system and that the system remains closed-loop stable. The effectiveness of the proposed control scheme is also demonstrated by a simulation example.