Tatsushi Tokuyasu

Mechanical modeling of a beating heart for a cardiac palpation training system

In cardiac plastic surgery, the cardiac surgeon touches the cardiac muscle to diagnose the patients heart that may be diseased due to infarction or dilate cardiomyopathy to determine the regions where it needs plastic surgery. In other words, the cardiac surgeon needs to recognize the mechanical characteristics of the thin muscle regions by the haptic sensitivity of his/her fingertips. Cardiac images available before cardiac surgery could enable a qualitative estimation of the patients heart. However, cardiac palpation is the only accurate way for making surgical plans for ventricular plastic surgery in the operating theater. Since young inexperienced cardiac surgeons have few occasions to perform cardiac palpation, even in operation cases, a cardiac palpation training system is highly desired. The training system for a cardiac palpation system we have developed consists of a virtual heart based on human left ventricular magnetic resonance images and a one-dimensional manipulator as a haptic device. Mechanical properties of the cardiac muscles of a pig and a dog are embedded into the virtual heart linked to a Windkessel model for the systemic circulation. Our experiments show that the developed training system enables users to feel the elasticity of the cardiac muscle wall through the manipulator in real-time.

A study on postural optimization for bicycle exercise based on electromyography

At present, commercially available bicycles have various sizes of frame to suit the user’s physical size, and the positions of both the saddle and the handlebars can be altered, but there is a lack of interest in the importance of the rider’s position when riding the bicycle in relation to their physical properties. Adjusting the rider’s position on the cycle on the basis of their physical properties before the exercise makes it possible to improve its efficiency. In this article, we develop an automatic saddle height-control system for cycle exercise, and present a useful method of determining cycling posture with the use of physical information. This system is composed of a computer, an electromyographic measurement device, and a fixed cycle trainer. In particular, in order to give the fixed cycle trainer a degree of freedom depending on the direction of the seat tube, we designed and built a device to control the height of the saddle. This article explains the structure of the system, introduces our data processing method, and discusses the results of our experiments. We then give an evaluation of the standard cycling posture for different settings of saddle height based on a quantitative evaluation method, principal component analysis.

Training System for Endoscopic Surgery by Using Augmented Reality and Forceps Control Devices

Endoscopic surgery is one of minimally invasive medical treatments, which reduces both physical and mental burdens of a patient than conventional abdominal operations. At present, a variety of training environments for endoscopic surgery, such as a dry box, a virtual reality (VR) simulator, and an animal experiment have been prepared to cultivate certifying physicians of endoscopic surgery. Even now, more effective training environments have been requested from the surgeons. Thus, this study proposes an application of augmented reality to establish a novel training environment of endoscopic surgery. We focused on one of Japanese learning styles in writing, in which children repeatedly trace the letters written on a sheet in order to learn how to use a pencil to write neatly without concerning the meanings of the letters. This study applies this learning style to our training system by using a dry box and augmented reality (AR). In our training system, AR Toolkit is utilized to describe a target trajectory which is displayed on a monitor and is refereed by a trainee. And we originally develops the devices which detect the motions of endoscopic forceps while training. This paper introduces the basic constitution of our training system and discusses about the training effects obtained from the experimental results with beginner subjects.

Development of a Training System for Cardiac Muscle Palpation

Touching the cardiac muscle is necessary to get mechanical conditions of muscle before cardiac surgery. The cardiac palpation is the only way to make surgical plans for left ventricular plastic surgery. The training system for cardiac palpation we have developed consists of a MRI-based virtual left ventricular image and a one-dimensional manipulator as a haptic device. Mechanical properties of the cardiac muscles of a dog and a pig are embedded in the virtual heart. Our experiments show that the developed training system enables users to feel the reactional force to the virtual heart surface from the manipulator in real time.

Predicting the individual best saddle height of bicycle based on electromyography and Fuzzy Inference

Recently, various social issues, such as global warming problem, economical abrupt move, and diseases associated with adult lifestyle habits, are reported. Against them, the role of bicycle has been reviewed as one of effective solutions. In fact, many types of bicycles have been developed and have been widely used in our daily life. Though commercially available bicycles have various size of frame for users physical size, and the positions both of a saddle and a handle can be modified, but there is a lack of interests in the importance of bicycle position as a shared awareness. Provision of proper riding posture for riders based on their physical properties would enable to improve the efficiency of cycling exercise, and to prevent some chronic pains occurred in places of body. To establish an optimization method of bicycle position based on individual biomedical information, this study focuses on the importance of bicycle position, especially we address to search a suitable saddle height corresponding to users physical features and properties. This paper firstly develops an automatic saddle height control system, and secondly supposes an evaluation standard of cycling exercise based on electromyographic signals of riders leg during cycling exercise, and an optimization method of saddle height by using Fast Fourier Transformation (FFT), Principle Component Analysis (PCA), and Fuzzy Inference. This paper shows firstly the concepts of the evaluation standard we have defined for riders pedaling performance with some experimental results, and introduces a fuzzy control system for automatic saddle height control.

Installation of Mechatronics Education Using the MindStorms for Dept. of Mechanical Engineering, O.N.C.T

The author constructed an installation course of mechatronics and conducted on the students of department of mechanical engineering, Oita national college of technology. The course is composed of six sessions and is aiming to grow up the mechanical engineers who can adapt quickly to changes in industrial society. Then, the education programs of computer technology and information processing are more emphasized in this course. Certainly the specific subjects involved with mechatronics are constructed as a part of curriculum in the older grades, however there is some difficulties to make students of department of mechanical engineering to have interests in electronics and/or information science. Viewed in this light, it is better to begin mechatronics education with undergoing experiments like this course since they were in early grade.

Development of a training system for intraoral radiography

Intraoral radiography is one of the effective diagnosis method for dental clinic, which is used to examine dental caries and gum disease. A patient needs to have a small film inserted in their mouth. The position and orientation of the film are properly adjusted by the dentist. An indicator cone which directs X-ray is set up outside the patients mouth. The intraoral radiograph provide a dental perspective projection image of the patients teeth, thus the individual differences of patients make it more difficult to take an appropriate radiograph regardless of the experience of dentist. Recently, the skills of intraoral radiography of Japanese dental students and intern doctors are declining. A conventional education method for intraoral radiography currently conducted does not provide enough time to master intraoral radiographic technique for the dental students, because much time to develop the roentgenogram is necessary. This paper describes the development of a training system for intraoral radiography. The system is composed of a notebook computer, two PHANToM Omni devices, and a dental arch model, where the PHANToM Omni devices are used to measure the position and orientation of a indicator cone and film of the system. We applied the computer graphics technique to draw an intraoral radiograph on the computer display, thus the system enables trainees to practice the intraoral radiography without a X-ray machine, lots of film sheets, and time for the development of roentgenogram. In this paper, we present the system structure, a simulation method for generating an intraoral radiography, and simulation results

Extraction of Physical Motion Dictating the Difference between Skilled Cyclist and Beginner

In the field of cycling competition, cyclists commonly utilize binding pedals to maximize their competitive performance. The feature of binding pedals is to hold the sole of cycling shoe on the upper body of pedal, which enables a cyclist to not only push down the pedals but also pull up the pedals in one revolution of pedaling motion. Pedaling motion is implemented by the combination of muscle activities of lower extremity. The conversion efficiency from the physical strength of a cyclist to the propulsion power of a bicycle has been considered as the skill of pedaling exercise. By the way, neither effective instruments nor methods to accurately evaluate the pedaling skill have been established. Then, this study aims to extract the difference of physical motions between a skilled cyclist and a beginner by using the mechanical data of a bicycle and the electrophysiological data of a subject while pedaling exercise. This paper firstly introduces the experimental device and describes the protocol of measurement experiment. The measured data are statistically processed by using principal component analysis to extract the physical motions dictating the difference of pedaling skill between a skilled cyclist and a beginner.

Construction of virtual patient model for maxillofacial palpation training system

Abstract Palpation has been considered as one of the important diagnostic skills for doctors, which is conducted on a patient to identify the size, the consistency, and the location of a subcutaneous tumor. Accurate palpation skill often detects the cause of disease early. Even in the field of dentistry, palpation has been considered as the important diagnostic skill for dentists. By the way, any practical training of palpation against a patient did not implemented in the dental education because the patient safety has a priority more than its educational effect. Then we propose a training system for maxillofacial palpation by using virtual reality and haptic interface. The details of modeling a virtual patient model for the training system are shown in this paper, and the experimental results are also described.

Development of automatic positioning system for bicycle saddle based on lower limb's EMG signals during pedaling motion

This paper proposes an automation system for cyclists, which provides the optimum setting of bicycle components such as saddle and handle against the physical properties of a cyclist. In order to complete our purpose, the evaluation criteria for saddle setting by using bio-signals of a cyclist who pedals a bicycle have to be established firstly. We focus on patterns of muscle activity of the leg muscles that activate in pedaling exercise, and assume that undesirable pattern of muscle activity would appear in the pedaling motion of inexperienced cyclists. We use principal component analysis (PCA) to extract the features of muscle activity from the leg muscles. Our previous work has already clarified that the PCA scores come close to zero in the pedaling motion performed by a skilled cyclist at the saddle height which is subjectively evaluated good. In this paper, we add other degrees of freedoms of saddle setting such as fore-and-back position and angle adjustment to the experimental device. Surface electromyogram (SEMG) of the leg muscles has also been used to measure bio-signals of a cyclist during pedaling exercise. With the use of the aforementioned experimental environment, the effects of setting height and fore-and-back position to the pattern of muscle activity of the leg muscles are investigated in this paper.