Teppei Tsujita

National Defense Academy of Japan | NDAJ · Department of Mechanical Engineering

A novel encountered-type haptic interface for surgical simulators is proposed. This interface has a container of MR (Magneto–Rheological) fluid, and an operator puts a surgical instrument into the fluid and can feel resistance force. The advantage of this interface is that an operator can move an instrument freely when it does not contact with MR f...

For improving surgical techniques of novice surgeons or preoperative planning, development of practical surgical simulators utilizing virtual reality technology have been expected in the medical field. During surgery, a surgeon uses a variety of surgical instruments. Therefore, a haptic interface should be able to display reaction force through var...

Discussions on how to perform tasks at disaster sites are actively conducted, but there is little debate on important issues such as how to deliver robots to disaster sites. To drop a humanoid robot with a parachute from an airplane is one of the promising ways of delivering robots. In this paper, the behavior of falling during parachute landing is...

Most haptic devices used in surgical simulators cannot display the force of multiple types of surgical instruments. To achieve this, an encountered-type haptic interface using magnetorheological (MR) fluid has been developed. This study aims to propose a scheme for displaying cutting force and elastic restoring force of soft biological tissue by th...

Introduction of surgical simulators, which enable repeated learning of new surgical techniques, is advancing and they are desired in the field of neurosurgery. This study aims to make a two-fold contribution. First is the development of a haptic interface, which can be used while changing the operative tools necessary for training the cerebral fiss...

This study proposes simulation-based surgical navigation concept and describes the development of a laparoscopic surgical simulator that reflects the motion of surgical instruments in the real world. In the proposed simulation-based surgical navigation, movements of the surgical instruments are captured by a motion capture system, and the movements...

Robots that operate at a disaster site have been proposed and the dispatch of rescue robots to such site is required. However, discussion on the transport of these robots is insufficient. One method of transporting such robots is to use an airplane and the parachute. In order to safely drop these robots by parachute, it is important to investigate...

A quad tilt-rotor UAV is a multicopter that can fly in arbitrary attitude by changing the thrust direction and can be applied independent position and attitude control. This paper proposes a tuning process using an adaptive PID control method for the position control system of a quad tilt-rotor UAV that does not require trial-and-error gain adjustm...

This paper proposes a detumbling method using eddy current brakes with permanent magnets for the second stage of the H-IIA rocket. This paper selects three candidate locations for generating the braking force and analyzes the effects of the eddy current depending on the location of the permanent magnet and the distance between the permanent magnet...

This paper presents the validation of thrust coefficients for multicopter UAVs in flight with propeller thrust measurement mechanisms. This paper describes a newer version of the thrust measurement mechanism to avoid resonance which occurred in the previous version. Flight experiments with the UAV equipped with the developed thrust mechanism are ca...

In this study, to realize a palpation simulator, we fabricate magnetic soft materials that can reproduce the wide range of elasticity between lesions and normal biological tissues. The magnetic soft materials consist of silicone gel as the polymer and carbonyl iron particles as the magnetic particles. In this paper, the elasticity of the materials...

This paper describes the fundamental experiment for automating the inspection of a paint coating thickness of spline plates on bridge with a robot arm. The inspection point is estimated using the registration between 3D point cloud data obtained from the actual model and that generated from the CAD model. In the experiment, a robot is set on unstab...

When UAVs approach each other, the airflow affects their flight performance. This paper describes the interaction between two UAVs when two UAVs are close to each other in the vertical direction. In this paper, the proximity flight is imitated with fixed UAVs and the forces applied to the UAVs are measured at different distances between the UAVs. T...

When using MR fluid to present the sensation of cutting, the fluid container is small, and the range in which the surgical tool and MR fluid can initiate contact is also small. In this study, we developed a control system that makes the fluid container follow the tool’s motion, thereby expanding the range in which cutting can start and the range in...

This paper describes the details of the data correction method and feature extraction for skill evaluation of practical laparoscopic surgical training. To analyze the surgical dexterity in practical laparoscopic surgical training, the motion capture (MoCap) based measurement system have been developed, and measurement experiment in cadaver surgical...

Endoscopic sinus surgery (ESS) is one of the standard minimally invasive surgical procedures for diseases of a nasal cavity and paranasal sinuses. This paper describes the development and details of a surgeon skill classification system using machine learning. A learning model was generated based on the features calculated from the dynamic measurem...

This paper describes fundamental evaluation of contactless item inspection using an unmanned ground vehicle (UGV) equipped with a terahertz (THz) sensor. To understand the characteristics of the THz sensor, THz waves were irradiated on an aluminum metal plate from distances of 1.0m, 2.0m, and 3.0m and reflected light was observed. In order to confi...

The Rapid Application Development (RAD) concept is an approach for developing high-quality computer systems in a short period using Computer-Aided Software Engineering (CASE) tools. This paper aims to build a RAD framework for UAV development to enable flexible and rapid verification for various hardware and software configurations. This paper pres...

Recently, multi-copters have been used in various areas, including outside and inside buildings. In the inside flight, airflow due to a wall or ceiling may affect multi-copters. This study aims to clarify the relationship between the airflow around the propeller and the force applied to the propeller near the wall using CFD (Computational Fluid Dyn...

In order to realize the deployment of a humanoid robot to a disaster site by parachute descent, it is necessary to generate a landing impact absorbing motion. This paper develops a dynamic simulator to demonstrate a motion of a one-legged robot with a Series Elastic Actuator (SEA) during the landing. First, the model parameters, such as spring and...

The goal of this research is to realize a robot development framework to prevent the abuse of robots using open source software. A basic framework has been proposed by demonstrating that program modifications can be identified by applying an image recognition method for malware and that a secure control system can be constructed using an FPGA and a...

Laparoscopic surgery is very difficult for surgeons and requires time and experience to master the technique, so an enhanced surgical navigation system is needed to assist the surgeon. In this research, we will develop a simulation system that displays the deformation of organs due to contact with surgical instruments calculated by the finite eleme...

In this paper, technical issues of body scanning with a teleoperated manipulator for contactless detection of dangerous items were clarified. A knife is concealed under the clothes of the model of a human body, and the manipulator with a metal detector attached to its end-effector is teleoperated to detect the knife. It was found that the system co...

In laparoscopic surgery, the problem is that endoscopic cameras have a narrow field of view and are often overlooked even if organs outside the field of view are damaged. As support, surgical navigation systems present the entire organ. However, because the navigation system uses preoperative medical images, the difference between the actual situat...

This paper describes the fundamental experiment for inspecting the paint coating thickness of spline plates of bridges with a teleoperated manipulator. In general, unstable suspended scaffolds are used at the bridge construction sites. In this study, the unstable scaffolds and the inspection area of a bridge are imitated, and the feasibility of the...

Neuronavigation is a computer-assisted technique for presenting three-dimensional images of a patient’s brain to facilitate immediate and precise lesion localization by surgeons. Neuronavigation systems use preoperative medical images of patients. In neurosurgery, when the dura mater and arachnoid membrane are incised and the cerebrospinal fluid (C...

Laparoscopic surgery is a minimally invasive procedure that is performed by viewing endoscopic camera images. However, the limited field of view of endoscopic cameras makes laparoscopic surgery difficult. To provide more visual information during laparoscopic surgeries, augmented reality (AR) surgical navigation systems have been developed to visua...

This paper presents force feedback control of an encountered-type haptic interface using MR (Magneto-Rheological) fluid based on biaxial forces measured by a surgical instrument with a single strain area. The haptic interface is developed for a surgical simulator. Therefore, the interface is supposed to display forces pressing or cutting the biolog...

The purpose of this study was to characterize the motion features of surgical devices associated with laparoscopic surgical competency and build an automatic skill-credential system in porcine cadaver organ simulation training. Participants performed tissue dissection around the aorta, dividing vascular pedicles after applying Hem-o-lok (tissue dis...

This research explores how robots can be used to protect parties to a conflict and civilians from suicide bombings in conflict areas under the international humanitarian law. This paper examines the issue from the perspectives of robotics and international law using a real robot. In this paper, the articles of international humanitarian law are int...

Background Our aim was to build a skill assessment system, providing objective feedback to trainees based on the motion metrics of laparoscopic surgical instruments. Methods Participants performed tissue dissection around the aorta (tissue dissection task) and renal parenchymal closure (parenchymal-suturing task), using swine organs in a box train...

During neurosurgery, brain deformation occurs because of gravity and leakage of the cerebrospinal fluid (CSF), which is referred to as brain shift. Brain shift is a serious problem in neuronavigation because neuronavigation relies on preoperatively taken medical images. This paper presents a brain shift estimation method based on hydrostatics and d...

A laparoscopic surgery is a minimally invasive surgery that reduces the burden on the patient. However, main disadvantage of the laparoscopic surgery is the narrowness of the field of view provided by an endoscopic camera. Therefore, if an organ is damaged by a surgical instrument outside the field of view, it is easily overlooked. To support the l...

In laparoscopic surgery, current surgical navigation systems use preoperative medical images. The actual shape of organs and the navigation image are different from each other due to the deformation of the organ during the operation. To solve this problem, our research group is developing an endoscopic surgery support system that can present intrao...

Multicopters are useful in a variety of fields. However, there is still a risk of loss of control due to updrafts or wind generated by the multicopter itself. Therefore, the goal of this research is to achieve robust flight against wind disturbances. As a first step, we develop an onboard airflow visualization system to visualize the airflow around...

Since laparoscopic surgery is performed through the images displayed on the monitor, it requires a higher degree of surgeons’ skills than open surgery, in which surgery is performed while directly checking the surgical field. In order to support decisions and surgical procedures in laparoscopic surgery, a surgical support system that displays defor...

Kinect has been utilized as a cost-effective, easy-to-use motion capture sensor using the Kinect skeleton algorithm. However, a limited number of landmarks and inaccuracies in tracking the landmarks’ positions restrict Kinect’s capability. In order to increase the accuracy of motion capturing using Kinect, joint use of the Kinect skeleton algorithm...

Background Our aim was to characterize the motions of multiple laparoscopic surgical instruments among participants with different levels of surgical experience in a series of wet-lab training drills, in which participants need to perform a range of surgical procedures including grasping tissue, tissue traction and dissection, applying a Hem-o-lok...

This article was updated to correct the labeling of Fig. 6.

Robots that operate at disaster site have been proposed, but how to transport robots has not been discussed. To drop the robots with a parachute from an airplane, it is important to investigate the aerodynamics coefficient of the robots in the free-fall before the opening of the parachute. In this study, the aerodynamics forces, which worked on the...

This paper describes the development of a surgical tool with a single strain area for measuring biaxial cutting forces. For measuring bending and compression forces in a single strain area, strain area needs to be sensitive to both bending and compression. In general, the bending strain is easier to measure compared with the compression strain. In...

There are many tasks that require a constant distance from the object, such as scanning with a hand-held metal detector or spray painting. However, in the teleoperation of the robot, it is difficult to understand the distance. In this paper, in order to solve this problem, a control method is proposed that compensates the distance between the objec...

This paper describes the detail of the objective surgical skill assessments from the viewpoint of a way of grasping organ with forceps in dissection procedure in wet lab training. In the surgical skill measurement experiments, 46 cases of grasping force/position of gripper in lymphadenectomy are measured. Surgical skill is analyzed based on six ind...

Life-size humanoid robots are expected to replace work at disaster sites, but there is little discussion about a quick introduction to the site. We will consider parachute descent as quick. In this case, we focus on landing impact, which is a big problem. A drop experiment was conducted to reduce impact by using a simple life-size one-legged robot....

Encountered-type haptic interfaces using MR fluid have been developed for surgical simulators. This haptic interface can display high-frequency force and can be used with various surgical tools. In order to develop this haptic interface, the relationship between display force and magnetic flux density is required in the design process. However, it...

Terahertz waves are electromagnetic waves which are frequency bands ranged from 0.1–10 THz. These waves have high transparency to non-metal, and high reflectivity for the metals. Expected to be application to non-contact exploration sensor for the dangerous goods, bomb, knife, and so on, the development to railway and airport is considered. In this...

This paper presents a surgical skill analysis based on the way of grasping organs with forceps in dissection procedure in a wet lab training for laparoscopic surgery. Forty-four medical doctors and students conducted lymphadenectomy training using laparoscopic surgical instruments and porcine cadaver organs. During the training, movement of surgica...

The objective of this paper is to propose a numerical calculation method for vessel preservation simulations to help brain surgeons in training techniques. Recently, neurosurgery simulators have been recognized as an effective training tool for surgical techniques. Vessel preservation is an important neurosurgical technique. Brain vessels are nonli...

This paper presents details of the development and validation of a measurement system for laparoscopic surgical procedures. An individual marker set is attached to each surgical instrument, and hence the developed system can simultaneously track multiple surgical instruments. The tracked surgical instruments can be exchanged during an operation. Th...

A surgical simulator is considered as one of promising applications in virtual reality and haptic fields. In our previous research, an encountered-type haptic interface using MR fluid had been developed. The system can display arbitrary force by controlling the magnitude of yield stress of the MR fluid and an operator can feel resistance force by c...

Motion capture systems are used to gauge the kinematic features of the motion in numerous fields of research. Despite superb accuracy performance, the commercial systems are costly and difficult to use. To solve these issues, Kinect has been proposed as a low-priced markerless motion capture sensor, and its accuracy has been assessed using previous...

This paper presents an examination of particles and dispersion vehicle of MR fluid for a surgical simulator using an encountered-type haptic device. We have developed an encountered-type haptic device using MR fluid for surgical simulator. Cutting biological tissue by operational instruments is demonstrated by cutting the MR fluid whose magnitude o...

In neurosurgeries, a neuronavigator is useful for improving safety. However, the brain displacement called brain shift is a problem which makes surgical images taken before surgeries inaccurate. In this paper, we describe a method of the real-time visualization of the brain shift using augmented reality (AR) technology and real-time physics simulat...

This paper proposes a Hardware-In-the-Loop-Simulator (HILS) for designing a robot which has flexible joints. The simulator consists of a hardware part, which flexible joints in this research, and numerical simulation, which calculates forward dynamics of whole robot system. By combining real hardware and numerical model, we do not need to model com...

Recently, medical technology has rapidly developed, and accordingly, the demand for surgical simulators has increased. An encountered type haptic device using MR fluid has been developed by our research group. The system can display arbitrary force by controlling the magnitude of yield stress of the MR fluid and the operator can feel resistance for...

Brain retraction is an important surgical technique that is used for lesion exposure in brain surgeries. However, in brain retraction, an excessive load may cause permanent damage to the brain. Therefore, the development of surgical simulators that can simulate the stress and force of brain reaction in advance of a real surgery is required. In orde...

This paper describes a way of massive object transportation by a humanoid robot. It is assumed that an object is too heavy for a humanoid robot to lift up, hence the object is transported by pushing or pulling. Model-based object transportation motion generation is discussed, in which a QP problem is solved on-line to optimize joint torques. In ord...

Motion capture systems are used to quantify kinematics of a motion in various fields of research. Despite high accuracy, commercial systems are expensive and complicated to use. The Microsoft Kinect has been used as an inexpensive markerless motion capture sensor but it has shown imprecision in measuring delicate motions. To address these limitatio...

To drop a humanoid robot with a parachute from an airplane is one of the promising ways of delivering robots to a disaster site, and this research has focused on how to absorb parachute landing shock. Two large impacts were observed in one drop test using a small one-legged robot in our previous experiment. The second peak could be reduced by the s...

Although how to perform tasks at disaster sites has been actively discussed, there is little debate on important issues such as how to deliver robots to disaster sites. We propose to drop a humanoid robot with a parachute from an airplane as one of the methods of delivering robots. In this research, we aim to establish a method to absorb the shock...

By using a surgery simulator, young doctors can train in surgical techniques to get essential skills and knowledge of surgery. In addition, surgeons can make a surgical plan and verify it. We have developed a neurosurgery simulator that can simulate surgical procedures in craniotomy such as brain retraction to expose a deep brain lesion. The simula...

Recently, the development in space is being progressed actively. Grasping is one of the fundamental actions in various space activities, such as an inspection of International Space Station (ISS), a docking of transfer vehicle to the ISS, a collection of samples of a planet and a removing space debris. However, grasping systems existing now on grou...

This paper proposes a visual haptic display with an encountered-type haptic interface using MR (Magneto-Rheological) fluid. The proposed system can display arbitrary force by controlling the magnitude of yield stress of MR fluid and provide realistic visualization by displaying computer graphics images on the container of MR fluid directly. An oper...

In this paper, I describe turning walk on loose soil of a humanoid robot. I propose landing position control to curb ZMP deviation on loose soil. I inspected effectiveness which is use a miniature humanoid robot.

This paper presents a walking control system for biped robots on loose soil. The proposed method realizes long time continuous walking and stable stopping on sand. Characteristics of the proposed system is landing position (modification) control. In this control, as a balance index, amount of CoM position modification is utilized. Considering past...

This paper proposes a visual haptic display with an encountered-type haptic interface using MR (Magneto-Rheological) fluid. The proposed system can display arbitrary force by controlling the magnitude of yield stress of MR fluid and provide realistic visualization by displaying computer graphics images on the container of MR fluid directly. An oper...

The generation of patient-specific models is one of the difficult problems in the clinical application of surgery simulators. In particular, when estimation of soft tissue deformation is required, a finite element (FE) mesh needs to be generated from the patient's medical images. One of the effective methods of FE mesh generation is the volume embe...

This paper presents a viscoelastic model of brain parenchyma which is based on the generalized Maxwell model but considers also inertial force. The proposed model is implemented in finite element method (FEM). The viscoelastic behavior of brain parenchyma was confirmed by stress relaxation tests using porcine brain parenchyma. The stress relaxation...