Motion Priority Optimization Framework towards Automated and Teleoperated Robot Cooperation in Industrial Recovery Scenarios

In this study, we present an optimization framework for efficient motion priority design between automated and teleoperated robots in an industrial recovery scenario. Although robots have recently become increasingly common in industrial sites, there are still challenges in achieving human-robot collaboration/cooperation (HRC), where human workers and robots are engaged in collaborative and cooperative tasks in a shared workspace. For example, the corresponding factory cell must be suspended for safety when an industrial robot drops an assembling part in the workspace. After that, a human worker is allowed to enter the robot workspace to address the robot recovery. This process causes non-continuous manufacturing, which leads to a productivity reduction. Recently, robotic teleoperation technology has emerged as a promising solution to enable people to perform tasks remotely and safely. This technology can be used in the recovery process in manufacturing failure scenarios. Our proposition involves the design of an appropriate priority function that aids in collision avoidance between the manufacturing and recovery robots and facilitates continuous processes with minimal production loss within an acceptable risk level. This paper presents a framework, including an HRC simulator and an optimization formulation, for finding optimal parameters of the priority function. Through quantitative and qualitative experiments, we address the proof of our novel concept and demonstrate its feasibility

Comparative studies of MRI and operative findings in rotator cuff tear.

A prospective study was performed to determine the accuracy of magnetic resonance imaging (MRI) compared with operative findings in the evaluation of patients associated with rotator cuff tears. Fifty-four of 60 shoulders (58 patients) examined by MRI were confirmed as full-thickness tears and 6 as partial-thickness tears at the time of surgery. The oblique coronal, oblique sagittal, and axial planes of T2-weighted images with the 0.5 tesla MRI system were obtained preoperatively and compared with operative findings. MRI correctly identified 46 of 54 full-thickness rotator cuff tears and 5 of 6 partial-thickness tears. A comparison of MRI and operative findings in full-thickness cuff tears showed a sensitivity of 85%, a specificity of 83%, and a positive prospective value (PPV) of 99%. A comparison of partial-thickness tears showed a sensitivity of 83%, a specificity of 85%, and PPV of 39%. Linear regression analysis showed an excellent correlation between the MRI assessment and measurement at the time of surgery (r = 0.90, P &#60; 0.01). MRI was useful in evaluating large and medium-sized rotator cuff tears, but less useful in distinguishing small full-thickness tears from partial-thickness tears.</p

InSAR analysis for detecting the route of hydrothermal fluid to the surface during the 2015 phreatic eruption of Hakone Volcano, Japan

Abstract Although the 2015 Hakone Volcano eruption was a small-scale phreatic eruption with a discharged mass of only about 100 tons, interferometric synthetic aperture radar successfully detected surface deformations related to the eruption. Inversion model of the underground hydrothermal system based on measured ground displacements by ALOS-2/PALSAR-2 images showed that a crack opened at an elevation of about 530–830 m, probably at the time of the eruption. A geomorphological analysis detected several old NW–SE trending fissures, and the open crack was located just beneath one of the fissures. Thus, the crack that opened during the 2015 eruption could have been a preexisting crack that formed during a more voluminous hydrothermal eruption. In addition, the inversion model implies that a sill deflation occurred at an elevation of about 225 m, probably at the time of the eruption. The deflation of sill-like body represents a preexisting hydrothermal reservoir at an elevation of 100–400 m, which intruded fluid in the open crack prior to eruption. The volume changes of the open crack and the sill were calculated to be 1.14 × 105 m3 (inflation) and 0.49 × 105 m3 (deflation), respectively. A very local swelling (about 200 m in diameter) was also detected at the eruption center 2 months before the eruption. The local swelling, whose rate in satellite line-of-sight was 0.7–0.9 cm/day during May 2015 and declined in June, had been monitored until the time of the eruption, when its uplift halted. This was modeled as a point pressure source at an elevation of about 900 m (at a depth of about 80–90 m from the ground surface) and is considered to be a minor hydrothermal reservoir just beneath the fumarolic field. Our analysis shows that the northernmost tip of the open crack reached within 200 m of the surface. Thus, it is reasonable to assume that the hydrothermal fluid in the open crack found a way to the surface and formed the eruption.Graphical abstractXXX

Temporal changes in inflation sources during the 2015 unrest and eruption of Hakone volcano, Japan

Abstract Global navigation satellite system data from Hakone volcano, central Japan, together with GEONET data from the Geospatial Information Authority of Japan, were used to investigate the processes associated with the volcanic activity in 2015, which culminated in a small phreatic eruption in late June 2015. Three deep and shallow sources, namely spherical, open crack, and sill, were employed to elucidate the volcanic processes using the observed GNSS displacements, and the MaGCAP-V software was used to estimate the volumetric changes of these sources. Our detailed analysis shows that a deep inflation source at 6.5 km below sea level started to inflate in late March 2015 at a rate of ~ 9.3 × 104 m3/day until mid-June. The inflation rate then slowed to ~ 2.1 × 104 m3/day and ceased at the end of August 2015. A shallow open crack at 0.8 km above sea level started to inflate in May 2015 at a rate of 1.7 × 103 m3/day. There was no significant volumetric change in the shallow sill source during the volcanic unrest, which is evident from interferometric synthetic aperture radar analysis. The inflation of the deep source continued even after the eruption without a significant slowdown in inflation rate. The inflation stopped in August 2015, approximately 1 month after the eruption ceased. This observation implies that the transportation of magmatic fluid to a deep inflation source (6.5 km) triggered the 2015 unrest. The magmatic fluid may have then migrated from the deep source to the shallow open crack. The phreatic eruption was then caused by the formation of a crack that extended to the surface. However, steam emissions from the vent area during and after the eruption were apparently insufficient to mitigate the internal pressure of the shallow open crack

Chronology of the 2015 eruption of Hakone volcano, Japan: geological background, mechanism of volcanic unrest and disaster mitigation measures during the crisis

Abstract The 2015 eruption of Hakone volcano was a very small phreatic eruption, with total erupted ash estimated to be in the order of only 102 m3 and ballistic blocks reaching less than 30 m from the vent. Precursors, however, had been recognized at least 2 months before the eruption and mitigation measures were taken by the local governments well in advance. In this paper, the course of precursors, the eruption and the post-eruptive volcanic activity are reviewed, and a preliminary model for the magma-hydrothermal process that caused the unrest and eruption is proposed. Also, mitigation measures taken during the unrest and eruption are summarized and discussed. The first precursors observed were an inflation of the deep source and deep low-frequency earthquakes in early April 2015; an earthquake swarm then started in late April. On May 3, steam wells in Owakudani, the largest fumarolic area on the volcano, started to blowout. Seismicity reached its maximum in mid-May and gradually decreased; however, at 7:32 local time on June 29, a shallow open crack was formed just beneath Owakudani as inferred from sudden tilt change and InSAR analysis. The same day mud flows and/or debris flows likely started before 11:00 and ash emission began at about 12:30. The volcanic unrest and the eruption of 2015 can be interpreted as a pressure increase in the hydrothermal system, which was triggered by magma replenishment to a deep magma chamber. Such a pressure increase was also inferred from the 2001 unrest and other minor unrests of Hakone volcano during the twenty-first century. In fact, monitoring of repeated periods of unrest enabled alerting prior to the 2015 eruption. However, since open crack formation seems to occur haphazardly, eruption prediction remains impossible and evacuation in the early phase of volcanic unrest is the only way to mitigate volcanic hazard

Precursory tilt changes associated with a phreatic eruption of the Hakone volcano and the corresponding source model

Abstract The 2015 unrest of the Hakone volcano in Japan, which began on April 26, generated earthquake swarms accompanied by long-term deformation. The earthquake swarm activity reached its maximum in mid-May and gradually calmed down; however, it increased again on the morning of June 29, 2015. Simultaneously with the earthquake increase, rapid tilt changes started 10 s before 07:33 (JST) and they lasted for approximately 2 min. The rapid tilt changes likely reflected opening of a shallow crack that was formed near the eruption center prior to the phreatic eruption on that day. In this study, we modeled the pressure source beneath the eruption center based on static tilt changes determined using both tilt meters and broadband seismometers. In the best-fit model, the source depth was 854 m above sea level, and its orientation (N316°E) agreed with the direction of maximum compression estimated based on focal mechanism and S-wave splitting data. The extent of the crack opening was estimated to be 4.6 cm, while the volume change was approximately 1.6 × 105 m3. The top of the crack reached to approximately 150 m below the eruption center. Because the crack was too thin to be penetrated by magma, the crack opening was attributed to the intrusion of hydrothermal water. This intrusion of hydrothermal water may have triggered the phreatic eruption. Reverse polarity motion with respect to that expected from crack opening was recognized in 1 Hz tilt records during the first 20 s of the intrusion of hydrothermal water. This motion, not the subsidence of volcanic edifice, was responsible for the observed displacement