A Compact Optical Six-Axis Force/Torque Sensor for Legged Robots Using a Polymorphic Calibration Method

This paper presents a novel design for a compact, lightweight 6-axis force/torque sensor intended for use in legged robots. The design promotes easy manufacturing and cost reduction, while introducing innovative calibration methods that simplify the calibration process and minimize effort. The sensor's advantages are achieved by streamlining the structure for durability, implementing noncontact sensors, and providing a wider sensing range compared to commercial sensors. To maintain a simple structure, the paper proposes a force sensing scheme using photocouplers where the sensing elements are aligned in-plane. This strategy enables all sensing elements to be fabricated on a single printed circuit board, eliminating manual labor tasks such as bonding and coating the sensing elements. The prototype sensor contains only four parts, costs less than $250, and exhibits high response frequency and performance. Traditional calibration methods present challenges, such as the need for specialized equipment and extensive labor. To facilitate easy calibration without the need for specialized equipment, a new method using optimal control is proposed. To verify the feasibility of these ideas, a prototype six-axis F/T sensor was manufactured. Its performance was evaluated and compared to a reference F/T sensor and previous calibration methods.Comment: 12 pages, 13 figures, 9 table

Effects of muscular response for the intensity of vibratory stimulus applied on the ankle tendon

The present study was conducted to measure the individual threshold value for the somatosensory system of the human body, the thresholds value of vibratory stimulus were assessed through the ascent and descent methods. In the interests of the attainment of this study`s goal, comparing the thresholds value measured and change of state of the muscles when applied on the ankle tendon connected to muscles, changes in threshold measurement accuracy due to the differences in measuring methods were discussed. The experiment was conducted by constructing systems to stimulate somethetic sensibility by vibratory stimulus, ultrasound imaging system and EMG system. Five adult males were involved in this experiment. According to the results of experiments, the threshold value of somatosensory stimulation measured by the ascent method was greater than the threshold values measured by the descent method. And the muscular response to the somatosensory stimulation applied to the tibialis anterior tendon showed a larger rate of change with the ascending stimulus than with the descending stimulus. The results of this study could serve as a basis to discuss the reliability of the measurement method of the human body’s individual threshold value for the somatosensory system through the ascent and descent methods and can be used as reference data for the integration and performance threshold measurement methods

A study on the changes in gait characteristics by applying sub-threshold vibration stimulus in the ankle

This study was conducted to suggest the potential use of a mechanical vibration stimulus in the ankle to correct gait abnormalities. As for the mechanical vibration stimulus, different locations and durations are suggested based on the detection results of real-time gait patterns. 5 young males participated in this study. They were asked to perform assigned gait tasks when either a threshold or sub-threshold stimulus was applied in the tibialis anterior and Achilles tendon. The analysis results of gait cycle and muscle activity showed the changes on gait cycle, the activity pattern of used muscle for gait and the movement pattern of the ankle were observed based on the applied locations of vibration stimulus. Also, the result of sub-threshold stimulus showed similar effects as that of threshold stimulus. As such, the mechanical vibration stimulus was considered to affect gait by being adjusted its characteristics and local stimulus also would affect human body systemically. The result of this study can be used as basic data for the correction of individual’s specific gait abnormality and rehabilitation using vibration stimulus

TCF/β-catenin plays an important role in HCCR-1 oncogene expression

<p>Abstract</p> <p>Background</p> <p>Oncogene <it>HCCR-1 </it>functions as a negative regulator of the p53 and contributes to tumorigenesis of various human tissues. However, it is unknown how <it>HCCR-1 </it>contributes to the cellular and biochemical mechanisms of human tumorigenesis.</p> <p>Results</p> <p>In this study, we showed how the expression of <it>HCCR-1 </it>is modulated. The luciferase activity assay indicated that the <it>HCCR-1 </it>5'-flanking region at positions -166 to +30 plays an important role in <it>HCCR-1 </it>promoter activity. Computational analysis of this region identified two consensus sequences for the T-cell factor (TCF) located at -26 to -4 (Tcf1) and -136 to -114 (Tcf2). Mutation at the Tcf1 site led to a dramatic decrease in promoter activity. Mobility shift assays (EMSA) revealed that nuclear proteins bind to the Tcf1 site, but not to the Tcf2 site. LiCl, Wnt signal activator by GSK-3β inhibition, significantly increased reporter activities in wild-type Tcf1-containing constructs, but were without effect in mutant Tcf1-containing constructs in HEK/293 cells. In addition, endogenous <it>HCCR-1 </it>expression was also increased by treatment with GSK-3β inhibitor, LiCl or AR-A014418 in HEK/293 and K562 cells. Finally, we also observed that the transcription factor, TCF, and its cofactor, β-catenin, bound to the Tcf1 site.</p> <p>Conclusion</p> <p>These findings suggest that the Tcf1 site on the <it>HCCR-1 </it>promoter is a major element regulating <it>HCCR-1 </it>expression and abnormal stimulation of this site may induce various human cancers.</p

Investigation of the physicochemical features and mixing of East/Japan Sea Intermediate Water: An isopycnic analysis approach

We present spatial distributions of the mixing ratio and properties of the East/Japan Sea Intermediate Water (ESIW) at its core density layer (σθ = 27.2–27.3) based on high-quality hydrographic data observed in the East/Japan Sea (EJS) during summer 1999. ESIW is defined as a source water type showing minimum salinity and maximum dissolved oxygen concentration. ESIW plays an important role in supplying dissolved oxygen and transporting anthropogenic carbon into the intermediate/deep layers in EJS. Studying the ESIW formation and distribution processes may provide insights on EJS\u27s shallow- to mid-depth thermohaline circulation and recent ocean changes. Here, we combine the previously estimated mixing ratio of ESIW, based on Optimum Multi-Parameter (OMP) analysis, and its physicochemical properties, such as pressure, dissolved oxygen, and phosphate, interpolated onto several isopycnic surfaces (σθ = 27.20, 27.25, and 27.30). The physicochemical properties of ESIW show steep north-south gradients across the subpolar front at 40–41°N. Higher dissolved oxygen concentrations (≥335 μmol kg–1) of ESIW are found in the western Japan Basin particularly off the Primorye coast, indicating a potential source region. The spatial and depth distributions of apparent oxygen utilization (AOU) on the ESIW isopycnic surfaces indicate that the subduction of ESIW occurs at 131–133°E (Ulleung Basin) across the subpolar front to the south. The density layer of ESIW shoals near the Korean coast in the Ulleung Basin, implying a potential link to coastal upwelling. The relative age of ESIW at its core layer is estimated from the oxygen utilization rate and AOU. The correlation between the pCFC12 and relative ages, and AOU estimated at 90% surface water oxygen saturation condition suggests a decadal-scale ventilation of ESIW (≤24 years). Younger waters at the ESIW coexist with the high-salinity intermediate water at the same density layer in the eastern Japan Basin. Our analysis suggests that ESIW is sensitive to climate forcing and an important shallow- to mid-depth thermohaline circulation component of EJS