Mitsuru Higashimori

The 100 G capturing robot - too fast to see

This paper discusses the capturing robot with the maximum acceleration of 100 G in design specification. We aim find the combination of the arm with a mass of 0.1 kg and the spring capable of producing the initial compressed force of 100 N, in order to achieve the 100 G. To reduce the total capturing time, we propose an arm/gripper coupling mechanism where the spring energy initially accumulated in the arm is transferred to the kinetic energy of the arm and continuously to the kinetic energy for closing the gripper at the capturing point without any time lag. The experimental results show the maximum acceleration of 91 G and the capturing time of 25 ms were achieved. Experiments on capturing a dropping ball were also executed with the assistance of the 1 ms-vision.

Noninvasive Assessment of Wall Distensibility With the Evaluation of Diastolic Epicardial Movement

BACKGROUND Left ventricular (LV) wall stiffening plays an important role in the development of heart failure with preserved ejection fraction (HFpEF). Based on the linear elastic theory, we hypothesized that the evaluation of epicardial movement during diastole is helpful for the noninvasive assessment of LV wall distensibility. METHODS AND RESULTS Based on the linear elastic theory, the epicardial movement index (EMI) was calculated on the echocardiogram as: [see text.] We calculated diastolic wall strain (DWS) as follows to examine whether DWS substitutes for EMI: [see text.] The animal study using hypertensive Dahl salt-sensitive rats, HFpEF model, and normotensive Dahl rats showed the significant and inverse correlation of EMI or DWS with myocardial stiffness constant. Preload alteration did not affect EMI or DWS. In the clinical study, the HFpEF patients had lower EMI and DWS than the normal volunteers and the asymptomatic patients with LV hypertrophy. CONCLUSIONS The evaluation of epicardial movement may be useful in noninvasively assessing wall distensibility in the absence of LV systolic dysfunction.

Dynamic Manipulation Inspired by the Handling of a Pizza Peel

This paper discusses dynamic manipulation inspired by the handling mechanism of a pizza chef. The chef handles a tool called ldquopizza peel,rdquo where a plate is attached at the tip of a bar, and he remotely manipulates a pizza on the plate. We found that he aggressively utilizes only two degrees of freedom (DOFs) from the remote handling location during manipulation: translation along the bar and rotation about the bar. From the viewpoint of a dynamic system, the inertial loads for these specific DOFs are never affected by the length of the bar. This is important for the production of quick plate motions so that the object on the plate can be dynamically and remotely manipulated. Applying this handling mechanism to a robot system, we first reveal how to make the objects motion for three DOFs by using two DOFs of plate motion. We then show that it is guaranteed to achieve an arbitrary desired set of position and orientation of the object by the proposed manipulation scheme. The proposed method has good manipulability because the translational motion of the object can be fully decoupled from the rotational motion (though not vice versa). Finally, we show a couple of experiments that confirm the basic idea.

A new stiffness evaluation toward high speed cell sorter

Cell stiffness could be an index for evaluating its activity. Although various systems measuring cell stiffness have been proposed so far, they are slow for adaptively connecting to cell sorters capable of handling more than 1000 [cells/sec]. This paper proposes a new approach that can indirectly evaluate the cell stiffness by measuring the passing time for a narrow channel. When a cell passes through the channel, it receives a viscous force depending upon how much deformation is exerted on the cell. We show that the stiffness is a function of both the passing time and the initial diameter of cell. We also show that the stiffness is proportional to the passing time and inversely proportional to the initial diameter, under the assumption that the thickness of fluid film is inversely proportional to the normal force. The experimental validation is given together with the basic working principle.

Design of the 100G Capturing Robot Based on Dynamic Preshaping

In this paper we discuss the design of the 100G capturing robot from the point of view of dynamic pre-shaping where all finger links make contact with the target object simultaneously. After briefly explaining the overview of the 100G capturing robot, we mathematically formulate the dynamic pre-shaping problem where we discuss how to determine the mechanical parameters, such as pulley positions, pulley radius, mass of finger link, and spring constant. We show a couple of experiments where the robot parameter is determined based on the dynamic pre-shaping problem.

Interleukin-16 Promotes Cardiac Fibrosis and Myocardial Stiffening in Heart Failure with Preserved Ejection Fraction

Background Chronic heart failure (CHF) with preserved left ventricular (LV) ejection fraction (HFpEF) is observed in half of all patients with CHF and carries the same poor prognosis as CHF with reduced LV ejection fraction (HFrEF). In contrast to HFrEF, there is no established therapy for HFpEF. Chronic inflammation contributes to cardiac fibrosis, a crucial factor in HFpEF; however, inflammatory mechanisms and mediators involved in the development of HFpEF remain unclear. Therefore, we sought to identify novel inflammatory mediators involved in this process. Methods and Results An analysis by multiplex-bead array assay revealed that serum interleukin-16 (IL-16) levels were specifically elevated in patients with HFpEF compared with HFrEF and controls. This was confirmed by enzyme-linked immunosorbent assay in HFpEF patients and controls, and serum IL-16 levels showed a significant association with indices of LV diastolic dysfunction. Serum IL-16 levels were also elevated in a rat model of HFpEF and positively correlated with LV end-diastolic pressure, lung weight and LV myocardial stiffness constant. The cardiac expression of IL-16 was upregulated in the HFpEF rat model. Enhanced cardiac expression of IL-16 in transgenic mice induced cardiac fibrosis and LV myocardial stiffening accompanied by increased macrophage infiltration. Treatment with anti-IL-16 neutralizing antibody ameliorated cardiac fibrosis in the mouse model of angiotensin II-induced hypertension. Conclusion Our data indicate that IL-16 is a mediator of LV myocardial fibrosis and stiffening in HFpEF, and that the blockade of IL-16 could be a possible therapeutic option for HFpEF.

Mechanical design of the Wheel-Leg hybrid mobile robot to realize a large wheel diameter

In this paper, a new category of the wheel-leg hybrid robot is presented. The proposed mechanism can compose large wheel diameter compared with the previous hybrid robot to realize a greater ability to climb obstacles. A prototype model of one Wheel-Leg module of the proposed robot mechanism has been developed to illustrate the concept. Actual design and mode changing experiment with a test mechanical module is also presented. Basic movement tests and a test of the basic properties of the rotational fingertip are also shown. The Basic configurations of wheel-leg retractable is considered well. The integrated mode is also described.

A device for the rapid transfer/transplantation of living cell sheets with the absence of cell damage.

In this study, we developed a device that could easily, rapidly, and completely transfer cell sheets from one material to another or transplant cell sheets onto the dorsal subcutaneous tissues of rats without leaving residual cells. Because the manipulation is as simple as pipetting, technical expertise is not required to transfer cell sheets very rapidly (the transfer time was 3.7 ± 1.6 s) using the device compared with that of a conventional method using a pipette (430 ± 180 s). After transfer by the device, C2C12 skeletal myoblast sheets showed active cell metabolism, cell viability, and very high production of vascular endothelial growth factor and stromal-derived factor-1α, indicating transfer without cell damage. Cardiac cell sheets after transfer showed spontaneous and synchronous beating, indicating intact cell-cell junctions and ion channel proteins on the cell surface. In addition, the device allowed us to transfer C2C12 cell sheets onto soft, rugged and curved surfaces such as human hands. Furthermore, cardiac cell sheets adhered rapidly and tightly onto the dorsal subcutaneous tissues of rats. This transfer/transplantation device may be a powerful tool in cell sheet-based tissue engineering and regenerative medicine.

Active shaping of an unknown rheological object based on deformation decomposition into elasticity and plasticity

This paper discusses an active shaping method for an unknown rheological object by considering the characteristics of viscoelasticity. By utilizing a four-element model for approximating the dynamic characteristics of objects deformation, we drive the deformation decomposition into the elastic response and the plastic one. For shaping the object, we then propose a two-phase strategy for controlling the resultant deformation; in the first phase the viscoelastic parameters are estimated with avoiding the over deformation, based on the elastic response; in the second phase the desired resultant deformation is generated by actively managing the integral force, based on the plastic response. This strategy has an advance that the handling time of the robot is given by a finite time, while the desired resultant deformation is theoretically completed in the infinite time. We finally show experimental results for confirming the validity of the proposed strategy.

Applying viscoelastic contact modeling to grasping task: An experimental case study

In this paper, we employ Fungpsilas viscoelastic model discussed by Tiezzi and Kao to study the experimental data presented by Sakamoto et al. for grasping viscoelastic objects using a parallel-jaw gripper. The viscoelastic contact modeling presented in this paper is characterized by two separate responses: elastic response and temporal response. Two main and intriguing results were found in the modeling and analysis of experimental data. The first is the consistency on the normalized coefficients for the curve fitting of the temporal response during the relaxation period of the grasping. Such consistency suggests that the proposed model is applicable to the grasping task at hand. The other result is the generic pattern of the elastic response deduced from the experimental data. The pattern of elastic response represents different physical significance of grasping which involves viscoelastic contact interface.