Applied Mechanics and Materials Vol. 145

Abstract: This paper proposes a new addressing method for high-efficiency switching-capacitor DC-DC voltage converter based on combination of CTS (charge-transfer-switch) charge pump and cross-coupled output stage is proposed in order to get a high output power and pump-efficiency. By using three level addressing methods, it can increase both of pump-efficiency and power-efficiency. The proposed three level addressing mixed-structure charge pump can operate at as high as 1MHz switching-frequency on the 0.1 μF pump-capacitors. Simulation by using HSPICE level 3 model shows that our work can convert the input low DC-voltage (V_in=1.5V) up near to 11.26 times of it (V_OUT=16.9V), so that more output power can be generated with a little power loss. The newly proposed addressing method for DC-DC charge pump circuit is suitable for various low-voltage applications.

Abstract: Walking is one of the basic human activities. Several well-defined, motion tracking systems have been used for gait analysis. However, these systems such as the optical motion tracking system are very expensive and limited to laboratory usage. Recently, microelectromechanical systems (MEMS)-based inertial sensors have made it possible to overcome these disadvantages. The aim of this study was to identify gait events and the supporting leg by measuring the mediolateral swing angle. An inertial sensor unit with a 3-axis accelerometer and 2-axis gyroscope was attached to the subject’s lower trunk using an elastic band. Five, healthy and young (20–29 yrs.) subjects participated in this experiment. Each walked twice along a straight, 25-m path at three different speeds. During each trial, the sensor transmitted signals to a PC via Bluetooth technology. In this study, gait events and the supporting leg were identified using the peak and sign of the mediolateral swing angle. The mediolateral swing angle was calculated using the integrated gyroscope signal. For comparison, a well-defined spatiotemporal gait analysis technique was also applied. In this reference method, the gait event was identified with the last peak of the vertical acceleration before the sign change from positive to negative. The supporting leg was identified using the sign of the mediolateral acceleration double integration. Identification of the supporting leg was difficult in the reference method because of the offset and gravity components in the mediolateral acceleration. However, the proposed method reported here, showed stable identification of gait events and the supporting leg. This study could be expanded to more detailed gait analysis with the additional fusion of a 3-axis acceleration, gyroscope and magnetometer.

Abstract: Shuffled frog leaping algorithm (SFLA) is a new meta-heuristic evolutionary algorithm with simple algorithm and effective calculation speed. It performs stochastic searching process that mimics natural biological evolution and the social behavior of species. SFLA conducts its formulation from two main methods, the local searching validated by particle swarm optimization and the competitiveness mixing of information implemented by shuffled complex algorithm. A modified shuffled frog leaping algorithm (MSFLA) is investigated that improves the leaping rule by properly extending the leaping step size and adding a leaping inertia component to account for social behavior. In this paper, a MSFLA is proposed to solve combinatorial optimization problem for a stand-alone photovoltaic (SPV) generation planning. Several practical installed and operated costs for a SPV system were used to trade off nonlinear system reliability in the three specified locations of Taiwan. Different degrees of loss of load hours and load profiles were investigated to achieve the long-term planning requirement.

Abstract: This paper presents a robust proportional-derivative (PD) based cerebellar model articulation controller (CMAC) for vertical take-off and landing flight control systems. It is known that PD control is a simple and effective control method. However, it does not ensure the robustness if it is used alone for uncertain systems. CMAC can be used for robust control. However, it requires training patterns for tuning some weighting factors. A novel CMAC incorporating with a PD controller design is proposed in this paper. Successful on-line training and recalling process of CMAC accompanying the PD controller was developed. The advantage of the proposed method is mainly the robust tracking performance against aerodynamic parametric variation and external wind gust. Even when the PD controller is not designed well, the CMAC is capable of doing a robust tracking control through on-line recalling and training procedures.

Abstract: In this paper, we propose an adaptive radio frequency identification (RFID) indoor positioning system technology for wheelchair home health care robot with wireless communication. The proposed RFID positioning system uses one reader and four tags which is low cost when applying in a large space of the indoor environment. It reduces the measured calculation by using multiple RFID tags instead of multiple RFID readers. While the measured experimental RFID data found with error leading to signal changes in different environmental parameters, we developed the adaptive fuzzy neural network technology to adjust the measurement data. Through the compensation of the measurement error, the actual wheelchair robot location-based application could be performed to overcome the uncertain environmental parameters. The positioning system provides very good accuracy and make home health care wheelchair robot positioning system available for navigation and guidance.

Abstract: The check is a popular form for the non-cash payment and accounts for more than 50% of the non-cash transactions. Magnetic ink character recognition system can recognize the check magnetic code automatically and get the information of the bank and account. In magnetic ink character recognition system, the recognizing algorithm is mostly based on correlation coefficient. The computational cost of this algorithm is very high. This paper has proposed a new algorithm based on the peak-valley code and peak-valley distance after analyzing the characteristics of magnetic code signals in E-13B standards to simplify the calculations and system design. Firstly, the magnetic code signal is normalized and separated into magnetic character signals by the thresholds of peak and valley. Secondly, the features of the peak-valley code and peak-valley distance of each magnetic character signal are extracted, then the recognition based on peak-valley code and the nearest neighbor recognition algorithm based on peak-valley distance are utilized to recognize the magnetic code. The recognition results and statistical parameters from a large number of experiments show that the new method has high recognition rate, good robustness and low computational cost.

Abstract: Counter-based Digital PWM (DPWM), the simplest DPWM device, can be easily implemented only by a counter and a comparator; however, the resolution of the counter-based DPWM is directly proportional to its input reference clock, and thus the higher clock frequency is required, which means higher dynamic power consumption and noise interference may be incurred. In this paper, without increasing the reference clock frequency, a new design approach using capacitor integration is proposed to extend the resolution of the counter-based DPWM, and it also can reduce the hardware complexity compared with the delay-line DPWM.

Abstract: Inspired by the studies of modern cognitive psychology and real-world pattern recognition systems, a new developed model for pattern recognition is proposed to provide an alternative solution for some complicated pattern recognition problems. This study exploits a creative problem solving (CPS) skill to derive a pattern recognition solution and presents the basic principles, criteria, and techniques for CPS. Next, CPS is devoted to develop pattern recognition application and demonstrate a case study. In addition, this paper discusses the case study on the application of CPS thinking model. Experiment results show that CPS thinking model can improve this application performance of pattern recognition.