Kayo Yoshimoto

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.

Retinal Projection Display Using Diffractive Optical Element

We have previously proposed a retinal projection head-mounted display (HMD) using the principles of the Maxwell Ian view. The principle of Maxwell Ian view can provide an image with a focal depth. In conventional HMD prototype, we have been using a holographic optical element (HOE) as an optical combiner. However, there are some problems with HOE. Therefore, in order to solve these problems, we propose the use of diffractive optical elements (DOE) of the phase-type based on computer-generated hologram (CGH). The paper show that phase-type DOE based on CGH is effective as retinal projection optical system.

Gastric Contraction Imaging System Using a 3-D Endoscope

This paper presents a gastric contraction imaging system for assessment of gastric motility using a 3-D endoscope. Gastrointestinal diseases are mainly based on morphological abnormalities. However, gastrointestinal symptoms are sometimes apparent without visible abnormalities. One of the major factors for these diseases is abnormal gastrointestinal motility. For assessment of gastric motility, a gastric motility imaging system is needed. To assess the dynamic motility of the stomach, the proposed system measures 3-D gastric contractions derived from a 3-D profile of the stomach wall obtained with a developed 3-D endoscope. After obtaining contraction waves, their frequency, amplitude, and speed of propagation can be calculated using a Gaussian function. The proposed system was evaluated for 3-D measurements of several objects with known geometries. The results showed that the surface profiles could be obtained with an error of <;10% of the distance between two different points on images. Subsequently, we evaluated the validity of a prototype system using a wave simulated model. In the experiment, the amplitude and position of waves could be measured with 1-mm accuracy. The present results suggest that the proposed system can measure the speed and amplitude of contractions. This system has low invasiveness and can assess the motility of the stomach wall directly in a 3-D manner. Our method can be used for examination of gastric morphological and functional abnormalities.

The Cleaning Effect of Shampooing Care by Adenosine Triphosphate Bioluminescence System

This paper discusses the cleaning effect of shampooing care by using Adenosine Triphosphate (ATP) bioluminescence system. Shampooing care is an important nursing one for patients who are difficult to care oneself. It is necessary to perform effective and comfortable care. So, we need to evaluate these effects quantitatively and qualitatively. We measured ATP, blood pressure, heart rate, heart rate variability, peripheral skin temperature and Visual Analog Scale (VAS) before and after shampooing. When we analyzed ATP adhering to head as “contamination” to evaluate that effect quantitatively, it found that the contamination of the scalp after shampooing decreased by 31%, and that of the hair decreased by 22%. The correlation between ATP and VAS showed that the more ATP decreased, the more subjects felt refresh. The physiological index was stable, and it found that the shampoo method in this study had little load on the body. We were able to clarify the cleaning effect of shampooing using rapid and simple method. These results showed can be the basic data that evaluated the effect by shampooing comprehensively.

Active outline shaping of a rheological object based on plastic deformation distribution

This paper discusses a shaping strategy of a rheological object whose deformation characteristic includes both elasticity and plasticity. We first introduce a seven-nodes viscoelastic model for approximating the outline and the dynamic characteristics of the object. Then, we show a shaping method of the objects outline, where the ratio between the objects length in the grasping direction and that in the perpendicular one is controlled by using a parallel jaw gripper. Based on the plastic deformation distribution for the integrated input stress, the proposed method can actively manage the final objects outline. In addition to the contribution on simplifying the grippers degree of freedom, this method has the advantage that the handling time is drastically reduced, compared with the position based passive method. We finally show the experimental results for confirming the validity of the proposed method.

Experimental study of creep response of viscoelastic contact interface under force control

Viscoelastic materials are known to exhibit temporal response that changes force or displacement at the contact interface under position or force control, respectively. In this paper, we conduct experimental study using force control to explore and observe creep phenomenon in robotic grasping in order to better understand the nature of such contact interface, which has been widely used in soft robotic fingers, robotic feet, and contact surface of robotic arms. We found that the creep response under a constant external force exhibits the characteristics of exponentially increasing or decreasing temporal response. Such characteristics are similar in nature to those found in the relaxation response of viscoelastic materials when the grasping is under position control. Two different types of creep responses are found, depending on the state of grasping. Both Types I and II in creep response mirror the Types I and II in relaxation response. We also found that different loading rates under force control result in different elastic response, in addition to the temporal response. This is an interesting finding because the Fungs model postulates for an elastic response that is independent of, and can be separated from, the temporal response. The experimental results do not show such independence.

An experimental study and modeling of loading and unloading of nonlinear viscoelastic contacts

The latency model is an analytical model for describing the behavior of nonlinear viscoelastic contact interface in robotic grasping and manipulation. The latency model is based on experimental observation of viscoelastic materials which exhibit the behavior of both elastic and temporal responses when subject to external force or displacement. It is postulated that such materials display latency in response of external influence by the rearrangement of molecules, holes, and structures in order to achieve an equilibrium state corresponding to the instantaneous loading. As a result, we propose that there are temporal latent activities in progress before the material reaches the equilibrium state. In the previous study [21], the latent activity of strain re-distribution with a prescribed constant displacement was presented using both theoretical modeling and experimental results. In this paper, we build upon this latency model to study the behavior of viscoelastic materials under different loading rates with experimental results. The latency model is employed to explain the behavior of responses of hard and soft viscoelastic materials typically found in robotic contact and grasping.

Continuous non-invasive blood pressure during continuous repositioning by pulse transit time

Abstract The purpose of the present study was to propose a method to measure continuous non-invasive arterial pressure (CNAP) of severely handicapped patient during continuous repositioning. We have been interested in healthcare for severely handicapped children. Although their long stay in hospital could be led to a circulatory disorder or a serious secondary disease, there was little way to give an adequate healthcare service for them due to several kinds of side effects. Thus, we developed the non-invasive sensor system to measure pulse transit time (PTT) through the different output signal between the two different measuring points. The proposed extended model of algorithm enabled us to measure continuous blood pressure (BP) with the measured PTT. The algorithm considered the influence of gravity on BP; there was no need to re-tune the system even if the posture of patient was changed. We performed the continuous repositioning experiment from the supine posture to 45 or 75° postures after the effectiveness of the proposed algorithm was confirmed. Through experimental results, it was found that the proposed method has the strongest correlation with commercial BP device. The experimental results showed that it was possible for the proposed algorithm to measure CNAP during continuous repositioning without the re-tune of system. It was recommended that some points of developed prototype hardware were necessary to be improved and the integration of other bio signals was more helpful for providing important insight into the overall physical condition.

Gastrointestinal tract volume measurement method using a compound eye type endoscope

We propose an intestine volume measurement method using a compound eye type endoscope. This method aims at assessment of the gastrointestinal function. Gastrointestinal diseases are mainly based on morphological abnormalities. However, gastrointestinal symptoms are sometimes apparent without visible abnormalities. Such diseases are called functional gastrointestinal disorder, for example, functional dyspepsia, and irritable bowel syndrome. One of the major factors for these diseases is abnormal gastrointestinal motility. For the diagnosis of the gastrointestinal tract, both aspects of organic and functional assessment is important. While endoscopic diagnosis is essential for assessment of organic abnormalities, three-dimensional information is required for assessment of the functional abnormalities. Thus, we proposed the three dimensional endoscope system using compound eye. In this study, we forces on the volume of gastrointestinal tract. The volume of the gastrointestinal tract is thought to related its function. In our system, we use a compound eye type endoscope system to obtain three-dimensional information of the tract. The volume can be calculated by integrating the slice data of the intestine tract shape using the obtained three-dimensional information. First, we evaluate the proposed method by known-shape tube. Then, we confirm that the proposed method can measure the tract volume using the tract simulated model. Our system can assess the wall of gastrointestinal tract directly in a three-dimensional manner. Our system can be used for examination of gastric morphological and functional abnormalities.

Three-Dimensional Light Field Display with Overlaid Projection

In the three-dimensional light field display, the quality of the 3D image depends on the resolution of the display device which is part of the system. A single LCD or projector device has been used as a display to construct the conventional 3D display. However, it is difficult to display the high quality 3D image by the system constructed of a single display device, because the resolution of the display device is limited. In order to solve this problem, we proposed the 3D display system with overlaid projection. The system consists of multiple projectors, a lenticular lens array sheet, and a condenser lens. In this system, light rays from a projector pass through a lenticular lens sheet and condenser lens and are observed directly. This paper describes the principle of proposed 3D display system, and the experimental results.