Applied Mechanics and Materials Vols. 479-480

Abstract: This study considered the application of fiber Bragg grating (FBG) to a composite material leaf spring as a vehicle loading sensing system. The loading of the vehicle by the leaf spring was calculated by the period change of the fiber grating caused by deformation of the composite material leaf spring under loading. From the experiment results, a good linear relationship between loading and Bragg wavelength shift for light. The R-squared value for the linear regression reached 0.99. The loading sensitivity is about 0.267 nm/N.

Abstract: In this paper, a novel disk piezoelectric actuator structure - 4-9-9-14 piezoelectric actuator is constructed, and it is made of piezoelectric buzzer to drive a biaxial piezoelectric actuated stage. The 4-9-9-14 piezoelectric actuator offers a better balanced capability of forward rotation and reverse rotation than the conventional edge-driving piezoelectric actuator. The biaxial piezoelectric actuated stage structure comprises a base, a V-shaped guide rail, an optical scale measurement system, a preload adjusting structure, and a load-carrying stage. The movement of a stage is read and analyzed by means of LabVIEW operating in conjunction with an optical scale. Stage movement-related signals read by the optical scale are processed. With a human-machine interface of LabVIEW, the movement of the stage is depicted by a waveform chart to thereby facilitate the observation of the waveform chart and the understanding of propulsion of the stage by the actuator.

Abstract: In this research, our research team used the self-designed piezoelectric actuator to achieve the micro/nanometer level precise positioning biaxial piezoelectric actuated stage through the redesign of stage mechanism. A novel piezoelectric actuator structure - 4-9-9-14 piezoelectric actuator is constructed, and it is made of piezoelectric buzzer to drive the stage. The movement of the piezoelectric actuated stage is read and analyzed by means of NI PCI-6115 data acquisition card and LabVIEW software operating in conjunction with a linear encoder. The new consideration of tuning time T_on is used to place of traditional method of changing the magnitude of driving voltage to control the stepping distance of the stage. Under a constant driving voltage, the displacement of the stage increases with time T_on, and the displacement of the stage decreases with time T_on. The aforesaid phenomenon occurs to leftward or rightward movement of the upper stage and forward or backward movement of the lower stage. Given a constant time T_on, the displacement of the stage in motion decreases with the driving voltage, and the displacement of the stage in motion increases with the driving voltage.

Abstract: This study presents a simple and low-cost spray coating process for producing high performance CO (carbon monoxide) sensors utilizing toluene-based gold nanoparticles (Au-NPs). Thanks to the success synthesis of Au-NPs in toluene, this low surface tension organic solvent prevents Au-NPs from colligation. And therefore Au-NPs can be well dispersed on the surface of the electrodes as the sensing layer during spraying. To compare with the typical metal oxide based CO sensors that have to work at a higher working temperature of about 150~350°C, the produced sensor can work at room temperature and have a better detection limit for CO gas (5 ppm). Experimental results indicate good linear sensitivity under repeated measurements for concentration range from 5 250 ppm (R²=0.996). The repeatability is also confirmed by measuring 100 ppm CO gas, the calculated variation is less than 2.8% for six repeating measurements. The process developed in this study can be used to produce not only high performance CO gas sensors but other related gas sensors.

Abstract: This paper presented a simple laser measuring method for measuring small displacement of a thin plastic string. The laser measuring method is based on the deviation of laser energy method. This measuring system consists of a laser diode and a photodetector. A photodetector received the laser beam from the laser diode is used to detect the laser energy deviation. A straight thin plastic string is placed between the laser diode and the photodetector to cover half area of the photodetector. When the string moves into or out the photodetector, the amount of the laser energy will change proportionally to the displacement of the string. A plastic string for the tennis is tested in this paper. The relation between the displacement of a plastic string and deviation of laser energy is verified by using a linear moving stage and a laser interferometer. The result showed the correlation is obtained. Thus, the displacement of a plastic string can be measured using the proposed laser measuring system.

Abstract: In this study, the multi-parameter bio-signals sensor was proposed to apply smartphones into m-health service application. The proposed sensor for the experiments was consisted of one set of two small devices; the size of each sensor was 25 mm × 20 mm × 4 mm. This sensor was made of either copper or titanium in order to pursue the better body affinity as well as electric conductivity. A manufactured sensor was able to measure for major bio parameters including electrocardiogram (ECG) signal of a channel, temperature, photoplethysmography, and body fat. Further, independent analogue hardware was manufactured to measure the each bio parameter. In results, bio parameters were easily obtained and they will be effectively applied into smartphones.

Abstract: The oscillating signals of NOx sensor observed in urea selective catalytic reduction (SCR) tests are explained via spectral analysis. The NOx sensor built by NGK / Continental requires decoding following the SAE J1939 protocol and thus higher harmonic induced by the discretization is observed in the spectral analysis. The reciprocating motion of the urea pump induces fluctuation of the ammonia dosage, which combined with the nonlinear characteristic from ammonia dosage to NOx downstream SCR result in oscillating NOx sensor readings with different amplitude. The cross-sensitivity of the NOx sensor to ammonia concentration for higher-than-stoichiometric ammonia dosage also results in oscillating NOx sensor signal at lower frequencies.

Abstract: In this paper, the photo diode sensors are used to realize the solar light detector for measuring the relative solar orientations. The proposed solar light detector comprises five photo diode sensors which are positioned on the front, back, left, right, and upper sides, respectively, on a cubic structure and cubic light-measuring detector is constructed. Accordingly, the photo sensors located on five facets can detect solar light from various directions and measure the incident solar power. Therefore, the relative solar azimuth and elevation angles can be measured precisely. The experimental results have confirmed the validity of the developed system.

Abstract: The purpose of this study is to design a redundant robot meeting the specific task and tracking the specific trajectory. Although the Moore-Penrose pseudo-inverse kinematic is commonly using to solve the inverse kinematic problem, it cannot solve the singularity exists in some situations that the rank of Jacobian matrix is not full rank for the redundant robot. Thus, a fuzzy motion planning algorithm is proposed to solve the inverse kinematic with singularity. Finally, we can obtain the position of five axes robot manipulator using fuzzy motion planning mapping method, and the errors of the singular points are approximately to zero. The results prove the fuzzy inverse kinematic mapping method can robust singular point when the tracking path with singular points.

Abstract: We consider an output based adaptive iterative learning control (AILC) for robotic systems with repetitive tasks in this paper. Since the joint velocities are not measurable, a sliding window of measurements and an averaging filter approach are used to design the AILC. Besides, the particle swarm optimization (PSO) is used to adjust the learning gains in the learning process to improve the learning performance. Finally, a Lyapunov like analysis is applied to show that the norm of output tracking error will asymptotically converge to a tunable residual set as iteration goes to infinity.