Accelerometric Technique Research Articles

Implementasi Gerakan Tangan terhadap Navigasi Robot Beroda menggunakan Teknik Accelerometer

Human-machine interface (HMI) is a system that can connect human organs to the control of a machine using computer technology. Today's robot technology has been widely researched, especially in terms of robot motion control. This research adopts the accelerometer technique by utilizing the wrist to control the motion of a wheeled robot via wireless communication. A wheeled robot as a data receiver and hand movements as a data transmitter. The MPU6050 sensor is mounted on the back of the hand to read hand movements based on the Pitch (y-axis) and Roll (x-axis) values. Communication between robots and hand movements using Bluetooth. The results prove that the accelerometer sensor on the MPU 6050 has successfully identified wrist motion as a remote navigation robot. Pitch value is greater than 160, so the robot moves backward and for moving forward is less than 140. Meanwhile, for moving left, the Roll value is less than 40 and for moving right is greater than 60.

Use of a non-invasive accelerometric method for diagnosing gastroesophageal reflux in premature infants

ObjectiveTo evaluate the clinical usefulness of a non-invasive accelerometric device to diagnose GER in preterm babies.Study designAn accelerometer was taped over the sub-xiphoid process in 110 preterm (GA 29.6 ± 3.3 wk) infants (133 studies). Low frequency, sub-audible signals were captured via digital recording (sampling rate 200 Hz), then re-sampled (rate = 60 Hz) to create a spectrogram (focused range 0–30 Hz). Mean amplitude in the focused range was calculated.ResultsOf 85 studies with simultaneous pH-metry and accelerometry, 18 had concurrent positive and 23 had concurrent negative scores, 42 had negative pH scores when accelerometry was positive (≥1 µV), consistent with non-acid reflux. Eleven infants at high risk of aspiration received surgical interventions. All but 1 had negative pH scores while 10/11 had positive accelerometry.ConclusionsThe non-invasiveness of this accelerometric technique allows for GER screening and for repeated testing to assess efficacy of interventions.

Diagnostics of seal and rod degradation in hydraulic cylinders using acoustic emissions

External leakage from hydraulic cylinders is of a major concern for the offshore oil and gas industry. This occurs mainly as a result of physical damage to the piston rod or due to degradation of the piston rod seals. Numerous studies have been conducted to diagnose leakage from hydraulic cylinders due to seal failure using fluid, pressure, accelerometer or acoustic emission-based condition monitoring techniques. However, very few attempts have been made to diagnose multiple faults in hydraulic cylinders at the same time. Therefore, in this study, acoustic emission-based condition monitoring technique is used to detect and separate acoustic emission features due to different faults that are observed in hydraulic cylinders. An experimental study was performed on a test rig using water glycol as hydraulic fluid. Experiments were performed with different combinations of seals (unworn, semi worn and worn seals), and piston rods (unworn and worn). Acoustic emission features such as root mean square, peak, mean, kurtosis, skewness, mean frequency, median frequency and bandpower were used to identify seal and rod conditions. By using acoustic emission median frequency and mean frequency features it was possible to detect and separate leakage, and seal and rod degradation in the test rig over a large range of hydraulic working pressures. This study indicates that acoustic emission monitoring can be a strong basis for future research to identify and segregate other types of faults that are observed in hydraulic cylinders.

An acoustic system for EOL engines diagnoses in hot test cells

End of Line tests have a crucial role in industrial processes to validate the products’ quality. In automotive industry, engines at the end of assembling process are fully tested within hot test cells at different working conditions by mean specific test cycles. Vibration monitoring is widely used in order to identify potential faults in the assembly process. This contact technique leads to several disadvantages, mainly due to the accessibility and the characteristics of surfaces for accelerometers mounting (e.g. rotating parts, geometries complexes, high temperatures) and to the time-consuming setup procedures. These limitations can be overcome by using microphone sensors. This paper describes the development phases of an acoustic based fault diagnosis system, its integration on hot test cells and the results obtained over large number of engines tested. By mean some specific technical solutions the acoustics approach in the EOL fault diagnosis of combustion engines has showed itself to be compatible with the characteristics of the production industry environment, providing reliable and repeatable results. The latter has been demonstrated also by comparison with the traditional accelerometer technique.

Detection of the time of foaling by accelerometer technique in horses (Equus caballus)-a pilot study.

Observation of preparturient mares is labour-intensive and time requirements would be reduced with automated monitoring systems. Recently, small-size accelerometers have become available. We followed the hypothesis that increased restlessness in mares shortly before the expulsive stage of labour can be detected with such accelerometers. Accelerometers were attached medioventrally to the halter of eight late pregnant mares. To evaluate an influence of accelerometer position, in one mare two additional accelerometers were attached close to the mandibular and atlanto-occipital joints. Accelerometers were programmed to send 600signals/min (10Hz). Signals were recorded continuously and, for evaluation, four intervals of 30-min duration on day 4 before foaling and the last 2hr before rupture of the allantochorion at foaling were selected. Signal detection was influenced by position of the accelerometer on the mares' halter. The highest signal detection rate was reached with the accelerometer in the lateral and dorsal position but differences of accelerations measured by the system differed neither between sensor positions nor between time intervals 4days before foaling. Differences of accelerations increased from 120min before foaling until birth of the foal (p<0.001) and this increase was most pronounced during the last 30-20min before birth of the foal (p<0.001). Technical improvements and a foaling specific algorithm are required to improve the accuracy to predict foaling. Even if this preliminary study included only a small number of mares, results demonstrate that accelerometers could be an important component of birth alert systems in horses in the future.

Measurement of Bridge Dynamic Responses Using Network-Based Real-Time Kinematic GNSS Technique

The network-based real-time kinematic (NRTK) global navigation satellite system (GNSS) technique was proposed for the first time to monitor the dynamic response of bridges. It could receive corrections from an established remote continuously operating reference station (CORS) network instead of a user-defined local reference station. To validate the feasibility of the NRTK-GNSS technique, laboratory and field experiments were both conducted at the University of Nottingham, U.K., and the Wilford suspension bridge, a footbridge close to the university’s campus. The conventional real-time kinematic (RTK)-GNSS and accelerometer techniques were synchronously considered for validating the accuracy of the NRTK-GNSS technique. A wavelet packet filtering scheme was designed to process full-scale experimental data according to the characteristics of NRTK-GNSS measurement noise. The dynamic displacements and vibration frequencies of the bridge were successfully identified from the NRTK-GNSS data with satisfactory accuracy. In conclusion, the study confirms that the proposed NRTK-GNSS can be a potential technique for the dynamic monitoring of bridges, with adequate performance and lower operational cost. It will be a powerful monitoring tool for structural health monitoring with continuous enhancement in the hardware and algorithm.

GPR Application – Non-destructive Technology for Verification of Thicknesses of Newly Paved Roads in Slovakia

The paper focuses on the use of non-destructive testing technology for measurement of asphalt and unbound pavement structure layer thicknesses for quality control and quality assurance within the context of civil engineering project handover process. In addition to layer thickness information, the pavement roughness was also verified using 3D accelerometer technique and IRI parameters were calculated and analyzed. This presentation summarizes the technology and results of a project where a special section of highway R2 Žiar nad Hronom bypass in the length of 5.2km was selected for the non-destructive testing. The processing and interpretation consists of extensive data sets presented as longitudinal profiles from survey of each lane of road. The designed layer thicknesses of the road were then compared with measured thickness data. In addition, a comprehensive presentation of the results in GIS view was produced to ensure the subsequent decision-making process easy to execute.

Hand Speed Measurements in Boxing

Hand speed is particularly important in boxing both for protection against incoming blows and delivering blows. Sixteen amateur boxers (10 male, 6 female) with varying levels of experience from a boxing gym performed 20 jabs and 20 cross punches in air. The movement was recorded with a small wrist mounted accelerometer under the glove. The maximum velocity of each punch was determined from the RMS acceleration profile. The mean values of the jab maximal velocity was higher than the cross maximal velocity for 9 participants. The cross showed some dependence on reach (Spearman's correlation coefficient r = 0.57) and the jab dependence on experience (Spearman's correlation coefficient r = 0.56). The accelerometer technique has some promise for routine assessment of fist speed.

Note: A balloon-borne accelerometer technique for measuring atmospheric turbulence.

A weather balloon and its suspended instrument package behave like a pendulum with a moving pivot. This dynamical system is exploited here for the detection of atmospheric turbulence. By adding an accelerometer to the instrument package, the size of the swings induced by atmospheric turbulence can be measured. In test flights, strong turbulence has induced accelerations greater than 5g, where g = 9.81 m s(-2). Calibration of the accelerometer data with a vertically orientated lidar has allowed eddy dissipation rate values of between 10(-3) and 10(-2) m(2) s(-3) to be derived from the accelerometer data. The novel use of a whole weather balloon and its adapted instrument package can be used as a new instrument to make standardized in situ measurements of turbulence.

Tower Bridge Movement Analysis with GPS and Accelerometer Techniques: Case Study Yonghe Tower Bridge

Tower Bridge Movement Analysis with GPS and Accelerometer Techniques: Case Study Yonghe Tower Bridge

Defocused CO2laser therapy in traumatic arthritis of the metacarpophalangeal joint: A randomized clinical study

AbstractA prospective, blinded, randomized and controlled study was conducted in horses with traumatic arthritis of the metacarpophalangeal joint in order to evaluate the efficacy of defocused carbon dioxide (CO2) laser therapy. Sixteen horses were randomly assigned to two groups: active laser (an output power of 16 W, scanned over 42 cm2, an average dose of 91 J cm− 2) and sham laser (the laser beam directed at the non-reflecting floor). All the horses received a total of five treatments during 1 week. The horses were evaluated with respect to the degree of initial lameness by conventional lameness examination and an objective accelerometer technique before the onset of treatment, and at 1 and 3 weeks. The concentrations of substance P (SP), prostaglandin E2(PGE2) and Met-enkephalin-Arg-Phe (MEAP) in synovial fluid were also assessed. Our study demonstrates that there was no significant difference in lameness score between the laser- and the sham-treated group before the treatment and at 1 and 3 weeks after the initial examination. Moreover, no significant difference in the concentrations of SP, PGE2and MEAP in synovial fluid in the active laser group compared with the sham-treated group was observed. In conclusion, this study suggests that treatment with defocused CO2laser in the management of traumatic arthritis of the metacarpophalangeal joint is not statistically better than sham treatment at reducing the grade of lameness as evaluated by conventional lameness examination and accelerometer technique.

ERRORS IN THE MEASUREMENT OF STRUCTURE-BORNE POWER FLOW USING TWO-ACCELEROMETER TECHNIQUES

This paper presents a theoretical study of three errors in the measurement of structure-borne power flow in one-dimensional structures using two-accelerometer techniques. It is assumed that the physical and material properties of the test structure are known. For the measurement of bending wave power flow, the errors due to the neglect of shear force and rotating inertia and the presence of longitudinal waves are examined individually. It is shown that the omission of shear force and rotating inertia results in a large bias error at high frequencies. The presence of incoherent longitudinal waves results in no bias error for the biaxial accelerometer technique or usually a negligible bias error for the two-accelerometer array technique. However, if longitudinal waves are coherent with bending waves the bias error increases with increasing the coherence and the longitudinal to bending wave energy ratio and becomes large when the bending wave energy is smaller than the highly coherent longitudinal wave energy. For the measurement of longitudinal wave power the effect of bending waves is important. As long as the bending wave power is not much smaller than the longitudinal wave power, the bias error is large even if bending and longitudinal waves are incoherent. Measures should be taken during measurements to eliminate or reduce the contribution from bending waves to a certain extent, otherwise, the longitudinal wave power cannot be measured using the two-accelerometer array technique.

Superconducting accelerometry: its principles and applications

After giving a brief historical review of their technological development, we discuss the principle of a superconducting accelerometer. We then expand into the design and optimization of various specialized accelerometers: superconducting gravity gradiometers and a superconducting six-axis accelerometer. We report the performance of these devices. Finally, we discuss how the superconducting accelerometer techniques are applied to various differential accelerometers in proposed space missions.

変形性膝関節症における膝側方動揺性の加速度測定による検討

This study investigated the correlation between lateral thrust of the knee joint and several parameters which are thought to influence the osteoarthritic knee. The degree of thrust was estimated applying the accelerometric technique. Fifty-eiqht osteoarthritic knees of 35 patients were studied with regard to height, weight, BMI (body mass index), osteoarthritic changes on roen tgenograms, difference of lateral joint opening angle of knee between an upright position and supine, and the point at the tibial plateau where the mechanical axis passes in a standing position. The latter two parameters on roentgenograms correlated with the degree of acceleration of osteoarthritic knee by multivariate statistical analysis, with correlation coefficients of 0.39 and -0.38 respectively. The results suggest that the accelerometric technique evaluates the lateral thrust of the knee joint quantitatively.

Sensory control of the male rat's copulatory thrusting patterns

The effects of reduced somatosensory feedback from the penis and/or the preputial region upon the male rat's copulatory thrusting patterns and sexual behavior were analyzed. Copulatory thrusting was recorded with an accelerometric technique allowing for the determination of duration and frequency of the thrusting trains. Section of the dorsal penile nerves (denervation) or lidocaine applied to the distal part of the penis reduced the number of intromissions and the intromission ratio. These treatments had no effect on copulatory thrusting patterns. Lidocaine injected into the preputial region also reduced the number of intromissions and the intromission ratio. Moreover, the number of disorganized mounts, as revealed by the accelerometric record, was much increased by this treatment. In addition, the duration of the thrusting trains associated with mount and intromission was increased. No effect was found on thrusting frequency. These data suggest that somatosensory feedback from the penis is critical for the achievement of intromission, whereas feedback from the preputial region is important for the execution of copulatory thrusting. Furthermore, it is possible that the strong sensory stimulation of the prepuce associated with penile insertion participates in the termination of thrusting and penile withdrawal.

Hypernasality in dysarthric speakers following severe closed head injury: a perceptual and instrumental analysis.

Hypernasality in the dysarthric speech of 20 severely closed-head-injured (CHI) subjects was investigated using both perceptual and instrumental techniques. A perceptual analysis of the speech of the CHI subjects was performed using a four-point rating scale for hypernasality. Instrumental assessment was carried out using a computerized accelerometric technique yielding a nasal coupling index. Results revealed a high incidence of perceived hypernasality (95%) in the speech of subjects in the CHI group. More than half of these subjects exhibited hypernasality of speech to a moderate to severe degree. When compared with a control group matched for age and sex the severely CHI subjects were perceived as being significantly more hypernasal. Instrumental assessment revealed that the functioning of the velopharyngeal valve in the group of CHI subjects was significantly impaired compared to the control group. The study highlighted the need to evaluate the perceptual and instrumental assessment results for the severely CHI subjects on an individual basis. The clinical implications of these findings are discussed.

The Influence of Nasal Patency on Accelerometric Transduction of Nasal Bone Vibration

The transmission characteristics of nasal tract energy to a nasal accelerometer were evaluated in relation to nasal tract airway resistance. Ten adult speakers repeated three utterances while recordings of nasal bone vibration, as detected by miniature accelerometers, were obtained simultaneously from both sides of the nose and referenced to a common throat signal. Average nasal-to-oral accelerometry ratios recorded from the more resistant side of the nose were significantly larger in magnitude than those recorded simultaneously from the less resistant side of the nose. While accelerometer ratio waveforms from each side of the nose essentially overlapped for some subjects, others displayed unilateral variations in accelerometer output as a function of time. The anatomic and physiologic condition of the nasal passage appears to be an important variable in the detection of nasal tract acoustic energy using the accelerometric technique.

Restoration of the copulatory pelvic thrusting pattern in castrated male rats by the intracerebral implantation of androgen

The characteristics of duration, vigour, frequency and rhythmicity of pelvic thrusting during copulation were studied by an accelerometric technique in 25 male rats before castration and following restoration of sexual behavior by local implants of testosterone propionate (TP) in the medial preoptic area (mPOA). Twenty-one Ss displayed the complete copulatory pattern during the control tests. Implantation of TP in the mPOA restored mounting activity after castration in 14 out of 21 Ss and only six of them “ejaculated.” Spinal cord structures involved in pelvic thrusting of castrated Ss implanted with TP were presumably not exposed to circulating androgen since the sexual accessories were atrophic; in spite of this, only modest differences were found in the characteristics of pelvic thrusting, i.e., an increase in the duration of the mounting trains of the TP implanted Ss. Present data suggest that activation of mPOA-anterior hypothalamic neurons would not only affect limbic and cortical areas related to sexual arousal through their ascending connections but would also modulate through descending pathways, the activity of lower spinal structures involved in copulation.

Sexual dimorphism in the motor mounting pattern of the New Zealand white rabbit: Steroid regulation of vigor and rhythmicity of pelvic thrusting

The motor mounting patterns of male and female New Zealand white rabbits were analyzed by means of an accelerometric technique and frequency analysis. Clear behavioral dimorphism was noted in the motor mounting pattern. Pelvic thrusting by males was periodic while that performed by females lacked rhythmicity. Thrusting in males was more vigorous than in females. Ovariectomy markedly decreased the incidence of mounting behavior. Testosterone propionate (TP, 5 mg daily for 1 month), restored mounting in all ovariectomized rabbits. TP stimulated the vigor of thrusting and induced a rhythmic mounting pattern in many cases similar to that displayed by intact male rabbits, i.e., thrusting frequency 13–16 per second. Estradiol benzoate (10 μg daily for 1 month), elicited mounting in three of the seven rabbits tested. Pelvic thrusting in these rabbits was often highly synchronous showing a frequency higher (18 to 21 thrusts per second) than that displayed by male rabbits. The results suggest the following conclusions: (a) the behavioral dimorphism in mounting observed in rabbits is due to variations in the secretion of sex steroids by the adult gonads rather than to differences in the organization of the neural substrate of mounting; (b) gonadal steroids influence directly or indirectly the neural structures involved in some characteristics of pelvic thrusting, i.e., rhythmicity and vigor.

Patterns of motor and seminal vesicle activities during copulation in the male rat

The interaction between behavioral and visceral events during copulation was studied in nine intact adult male Wistar rats. The motor copulatory pattern was analyzed by an accelerometric technique and the seminal vesicle pressure (SVP) was recorded through a catheter chronically inserted into the right seminal vesicle. Mounting was associated with a small broad rise in SVP that often preceded the initiation of pelvic thrusting. Penile insertion resulted in a second sharp rise in SVP superimposed on the primary wave related to mounting. A steep rise in SVP occurred during the performance of the motor ejaculatory pattern after a variable period of intravaginal thrusting. This final rise was associated with ejaculation. Analysis of the temporal relationships between the SVP changes and copulatory behavior revealed that each of the three rises of SVP was related to distinct patterns of stimulation, suggesting that they were mediated by separate reflex arcs.