Applied Mechanics and Materials Vols. 284-287

Abstract: Up to date, smart phone with built-in sensors (tri-accelerometer, GPS) and Internet access has become a useful kit for many purpose using. In this paper, we present the design and the implementation a combine approach for the detection of falls by smartphone. It used analyzing of body postures, mobility and falling location to recognize falls happened. In this paper, we present a system with real-time classification of human movements based on built-in sensor of smartphone. At the same time, it is able to classify the data for falling recognition. In our algorithm, it is not only to analysis of body postures by tri-accelerometer, but also to analysis of falling location by GPS sensor. We used a parameter called falling-risk (FR) to measure falling risk at different location. The FR is based on falling history at GPS location (x, y). It will alarm falling with fall location when falling and it will notice when user entered the high risk area. The major advantage of the proposed system is the novel application of smartphone which already have the necessary sensors and can monitor fall ubiquitously without any additional devices. We develop an Android application that monitors the phone’s built-in sensors, detects falls, and generates high risk alerts when user passes through the high risk area. We test the application against a number of Activities of Daily Life (ADLs) and fall events, and present the results.

Abstract: In this paper, we proposed a novel texture preserving optical flow technique to estimate the motion patterns of contrast agent on the ultrasound image. The proposed method estimated the motion fields based on three major steps. Firstly, the proposed method recomposed the original image based on the weighted structure-texture decomposition. Secondly, we applied a slightly non-convex approximation approach by utilizing the spline interpolation based coarse-to-fine warping scheme to handle the motion discontinuities in ultrasound image. Lastly, after each warping step, we employed the bilateral filter into the numerical framework to minimize the tracking errors in motion estimates. To evaluate the tracking performance of our method, we estimated the motion fields of microbubbles for the tissue mimicking phantom, and compared its results to those of the existing methods. As a result, it was found that the proposed technique provides the most reliable motion patterns of microbubbles, and reduces computational loads, simultaneously. We also confirmed the potential usefulness of our estimation scheme for the microbubble based diagnostic analysis.

Abstract: This study focuses on establishing an in-vitro sound filed measurement system in order to investigate the effect of sound source angle and frequency on the head shadow effect (HSE). The study used sound stimuli at frequencies of 125 Hz, 250 Hz, 500 Hz, 750 Hz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 5 kHz, 6 kHz, 7 kHz, 8 kHz, and with sound source positioning at angles of 0, 30, 45, 60 and 90 degrees. It evaluated the effect these frequencies and positioning combinations had on the HSE. When the sound source was positioned at 90 degrees to the ear, this study found that the HSE not only existed at the frequencies of 4 kHz to 6 kHz, but also the HSE could be happened at 3 kHz, 7 kHz and 8 kHz. In addition, a significant influence on HSE was also demonstrated when the sound stimulus was positioned at 45 degrees to the ear, with a frequency range between 3 kHz~8 kHz. As well as considering head and ear anatomy and the head shadow effect when selecting and fitting hearing aids, it is also necessary to consider adjustment to account for angular sound sources at different sound frequencies.

Abstract: Error compensation is an effective and inexpensive way that can further enhance the machining accuracy of a multi-axis machine tool. The volumetric error measurement method is an essential of the error compensation method. The measurement of volumetric errors of a 5-axis machine tool is very difficult to be conducted due to its complexity. In this study, a volumetric-error measurement method using telescoping ball-bar was developed for the three major types of 5-axis machines. With the use of the three derived error models and the two-step measurement procedures, the method can quickly determine the volumetric errors of the three types of 5-axis machine tools. Comparing to the measurement methods currently used in industry, the proposed method provides the advantages of low cost, easy setup, and high efficiency.

Abstract: This Paper Proposed a Low-power Smart Temperature Sensor. the Sensor Consisted of a PTAT Circuit, and a Ring Oscillator. the Current of the PTAT Circuit Was Used to Drive the Ring Oscillator which Generates a Temperature Related Signal. the Sensor Was Implemented by the TSMC CMOS 0.35 µm 2P4M Digital Process. the Core Aµµrea Is only 1105.59 µm². the Power Consumption Is aboutµ 159.15 nw. the Linearity between the Output Frequency and Temperature Is Marked by R-square Rule. the Value of the Linearity Is 0.991 during the Temperature Range. the Proposed Sensor Required only One Supply Voltage. the Core Area Was Small. Therefore, the Sensor Was Suitable for Embedded in any Circuit that Required Temperature Monitoring.

Abstract: This paper describes a method for generating a center of gravity trajectory of a biped humanoid robot under variable reference ZMP trajectory. A simple inverted pendulum model (SIPM) is used to calculate a center of gravity (CoG) trajectory from a reference zero moment point (ZMP) trajectory with an analytic form, which is based on the Fourier series. Fundamentally, we used a time segmentation based approach. For each segment, we defined its duration and boundary conditions, which are the key parameters of ZMP trajectory design. After designing the ZMP trajectory in each segment, we can automatically calculate the CoG trajectory by matching the boundary conditions and by calculating the coefficients between the time segments. The reference ZMP trajectory can be changed by updating the boundary conditions during walking. We successfully verified the proposed method through full-body dynamic simulations with variable step length.

Abstract: A technique using surface wave energy to move a sensor platform up and down a mooring wire is introduced in this paper. It permits a complete vertical profile to be obtained with a single sensor, eliminating the need for multiple sensors on the mooring line. The sensor platform can be pre-programmed to dwell at depth for set periods of time. The platform can be configured to carry a variety of payloads including CTD, optical and acoustic sensors.

Abstract: An adaptive nonlinear trajectory tracking design for mobile robot and its practical implementation are presented in this paper. The design objective is to specify one nonlinear controller with a parameter adaptive law that satisfies the adaptive H2 optimal performance. In general, it is hard to obtain the closed-form solution from this nonlinear trajectory-tracking problem. Fortunately, based on the property of the trajectory tracking system of the nonholonomic mobile robot, the adaptive H2 trajectory tracking problems can be reduced to solving one nonlinear time varying Riccati-like equations. Furthermore, one closed-form solution to this nonlinear time varying Riccati-like equation can be obtained with very simple forms for the preceding control design. Finally, there are two practical testing conditions: circular and S type reference trajectories are used for performance verification.

Abstract: In nuclear power plants, there are many cables that perform safety-related functions. These cables should implement condition monitoring during the operation period in the nuclear power plant, in order to assess the remaining qualified life and extend the qualified life. In this study we focused on the indenting method which can measure the hardness of the cable jacket. This method is selected because it is non-destructive and requires short testing time and small sized equipment. In order to address the problems with the existing indenting test equipment, we developed new indenting test equipment, which could automatically move on the surface of the object cable. The newly developed equipment is designed for a small-sized and light-weight robot using wireless communication in order to implement condition monitoring in a harsh environment or locations that are inaccessible to the tester. The developed wireless cable indenting robot is composed of three parts, which are mechanical and electrical hardware parts and remote-control part. In order to analyze the degradation tendency of the cable, we prepared four thermally aged specimens and one un-aged specimen. Using the developed robot, we measured the modulus of the cable jacket of each specimen. The test data showed that the modulus of the cable jacket increased linearly as the accelerated aging time increased. From these results, we can analyze the degradation trends pertaining to cables installed in nuclear power plant according to the operation period.

Abstract: Automotive industry is growing widely and rapidly by the involving of multi-fields not only mechanical engineering but also electrical and electronic engineering, material and more. As a key system in vehicles, suspension system and its control have been studied for a long time. A well-controlled suspension system provides high vehicle handling, good drivability and high comfort for passengers, and good isolation from road noise and vibration. To enhance comfort and handling of light-weight vehicles, semi-active suspension system is considered and proposed by numbers of papers. A semi-active suspension features small system space, low complexity and easy maintenance. Therefore, it is suitable for small compact car body known as light vehicles. This paper focuses on the analysis and control of a semi-active suspension for light-weight vehicles. Models of a quarter-car suspension with air spring and magneto rheological damper were built. Because components in the system involve nonlinear dynamic characteristics, a self-tuning Fuzzy logic controller was designed. Simulation results showed that the designed suspension system with its controller had good performance in vibration suppression.