High intensity focused ultrasound (HIFU) has a great potential for the treatments of stones and/or tumors. In HIFU therapy, respiratory organ motions make it difficult to locate the HIFU focus onto the focal lesions and the risk for damaging the surrounding healthy tissues could be increased. Therefore, we have developed the ultrasound guided motion tracking systems for the moving organs, such as kidneys and livers. Here, the changes of the image patterns seriously deteriorate the motion tracking performance for the focal lesions. To cope with this problem, we proposed a novel motion tracking method to switch templates in accordance with the organ positions in the body. Our method works robustly, even if the image patterns change in accordance with the respirations. Experimental results show the validity of our proposing motion tracking method for the kidneys and livers.

With the objective of developing a system for surgical scalpel cutting skill training, a prototype specialized for measurement and modeling capabilities was produced, based on the concept of Haptic Recorder. RT method was applied for pattern recognition and discrimination of the scalpel dissection skills between two types of knife and practice sessions. In this report, we propose an inverse analysis method of RT method to generate a target featured reference data from the prerecorded frequent practice trainee. As a simulation, target tool and stage force data are computed in relation to the knife tip position, based on the prerecorded sensor data of dissection of gelatinous substance. The differential data were computed comparing the model data and the actual recorded data of less experienced subject data. The results showed tidy difference to be used to project a guide force to the trainee.

As one of surgical instrument, an abdominal retractor which has six-DoF with high reliability is developed as substitutes for use during surgery. The proposed retractor consists of a serial three-link arm and three ball joints. During surgery, the retractor needs to maintain the shape of the relevant body part while maintaining own posture. The proposed instrument can increase the efficiency of surgery. Spherical joints can be driven by operator manual operation through inner/outer cables. In particular, in order to strengthen the holding force, it is processing dimples on the ball. In addition, we introduce a knock mechanism as another holding/release mechanism.

Surgical treatment of the eye fundus involves the insertion of thin surgical tools into the eyeball, that have to interact with the micrometer-scale structures of the eye. In such small scale, manually handling the instruments is especially challenging, since involuntary hand tremors alone can have larger amplitudes than the structures being handled. In order to enhance the precision of surgeons in such delicate task, we designed a master-slave eye surgical robot to assist in vitreoretinal surgery, based on a 6-PUS parallel mechanism to provide high precision, while being compact as not to clutter the operating room. Experiments demonstrate that the developed robot in master-slave control provides higher accuracy compared to manual handling. In order to further enhance its usability, an autonomous 3-D surgical instrument positioning method based on visual servoing and contact detection was implemented. That method was evaluated in the automation of cannulation procedures in a manner that is compatible with clinical reality.

A new manipulator with a detachable commercial forceps has developed that can act as a third arm for a surgeon situated in a sterile area near the patient. A mobile locally operated detachable end-effector manipulator (LODEM) with ratchet mechanism for force limiter was developed and tested. The manipulator prototype consists of a parallel-linkage slider-crank mechanism for yaw axis, a balanced center of gravity for pitch axis and a wire transmission for insertion axis. The prototype uses the adjustable spring back force ratchet mechanism for each stepper motor to achieve both manually-operable and motor-drivable manipulator. The mass was 5.8 kg for the manipulator prototype. The ratchet prototype was 0.4 kg of the mass and 90 % of the transmission efficiency. A mobile LODEM 4.0 was designed that allows minimally invasive robotically assisted endoscopic surgery.

A quantitative and effective evaluation of a human lower limb movement is very important in clinical gait analysis for elderly people. Therefore, we propose a gait evaluation method which can be applied for the gait analysis to prevent falls. In this paper, we measured and analyzed the key feature of elderly people's gait and discussed the risk of fall.

This paper presents a needle shooting device at high-speed for the puncture treatment. Problems of the puncture treatment are a curving of needles and a moving of organs because doctors puncture a needle at low speed. We assumed that puncturing a needle at high-speed can solve these problems. The needle with thread is used for inserting treatment instruments into the body. Coil-gun and Railgun were used for the small needle acceleration. We measured relations between the voltage and the velocity on Coil-gun and Railgun. In the case of Coil-gun, the velocity do not monotonous increases as the value of voltage increases. In the case of Railgun, the velocity monotonous increase as the value of voltage increases. The experimental results show that a needle with thread can be accelerated by Coil-gun and Railgun.

To develop a further compact, lightweight, versatile surgical robotic system for laparoscopy, we designed novel robotic forceps developed based on compliant mechanism within the diameter of 6 mm. In this paper, we present the mechanical model and its evaluation tested on the prototype.

Surgery conducted with an endoscopic camera is challenging for surgeons because they typically cannot precisely determine the scale of internal organs or gauge the distance between organs and forceps due to the limitations of stereo visual perception. The purpose of this study is to develop a surgery assistive system for a laparoscopic surgery by using an omnidirectional camera. We developed a prototype that displays omnidirectional images inside a box training system through a head mounted display.

We proposed an active in vivo power generation system using electrical muscle stimulation as an alternative to an implanted battery and a-transcutaneous drive line. In this system, skeletal muscle contraction generated by applying electrical stimulation was used to drive a power generator. In this paper, an electromagnetic induction type one was designed to be compact, durable and efficient. The muscle contraction is transmitted to an oscillator supported by parallel leaf springs through a non-contact clutch mechanism using magnetic force. The experimental electric power generation was 20.9 μW, and the energy efficiency was 24.7%.

In this research, we developed a surgical robotic system which consists of pneumatically-driven hand-held forceps with 2-dof wrist joint and 4-dof forceps holder. A master-slave type wrist joint, in which the master is integrated the hand-held forceps itself, is proposed. Moreover, intuitive operation is realized by an active transformation from the surgeon's wrist-rotation to the tip-rotation using an IMU and the pneumatic cylinders. Finally, we experimentally confirmed the joints and the tip rotation controls are satisfactory.

Microbubbles are expected as carriers of acoustic targeted drug/gene delivery therapy. To realize the therapeutic system, we have proposed a technique that controls microbubble behavior in blood vessels using ultrasound emitted from the body surface. To apply this technique in vivo, robotic positioning of therapeutic devices on body surface is required. For this purpose, though we have developed a robotic system using parallel link robot, the motion of the diagnostic probe positioning was not included in the previous system. To carry out the cooperation between ultrasound diagnosis and therapy at the same time, we have developed a gripping mechanism of multiple sound sources. In this paper, we introduce the prototype of this mechanism and perform evaluation experiment of positioning accuracy. The results demonstrated that the system has a great potential to realize accurate positioning with 1.5mm in translation and 2.5deg in rotation.

We propose a laparoscopic surgery supporting system by using effect of skill transmission of the view-sharing. To realize overlapping the video of expert's motion onto trainee's view with very low latency and without jitter, we developed the custom hardware for synthesize images. Additionally, the movement mechanism of expert's camera is implemented to following the laparoscope camera, and then the trainee's forceps and teacher's forceps are viewed from the corresponding position.

Permanent brachytherapy with 198Au grains for oral cancer can reduce the burden of patients. Since surgeons insert the radiation source by hand, they are exposed to radiation during the brachytherapy operation. To reduce the radiation exposure, we developed a remotely operated brachytherapy system previously. The system has a remotely insertion device and a gripper. The gripper needs to open the mouth and shift the gripping place. In addition, oral organs have slippery and flexible surfaces. In this paper, we produced a new type of sucker for the gripper. The sucker has balloon bellows that can transform its surface passively. It can grasp a flexible and slippery object as a human oral organ with no slip.

We have developed the Sensorimotor Enhancing Suit (SEnS) and revealed that the SEnS can unload the load of one's upper limb and then improve the force perception capability. In this study, we develop a new version of SEnS for a laparoscopic surgery. The SEnS for the laparoscopic surgery was designed to unload the muscle effort around one's shoulder, and it also helps to maintain the appropriate posture for the surgery. We measured smoothness of motions during forceps manipulations when wearing the SEnS. The experimental results show that the SEnS can improve the smoothness of motions.

Lifestyle-related disease patients by the rapid change of lifestyle and social environment in Asian countries of high economic growth have increased. In addition, there are low rate of getting a medical check-up and many infectious diseases. Therefore Asian countries need the health sensing system that allows infection prophylaxis and mass visits. In this study, a user easily performs a medical check-up for the early detection of ills including the lifestyle-related disease and provides the system that can manage the diagnosis information. The non-contact sensing system of height and body temperature is developed for infection prophylaxis and reduction of inspection time. The user can receive the benefit of the advanced medical institution of foreign countries far distantly as well as a local medical institution, because the health sensing system spread widely.

Against the background of increasing the number of cases of endoscopic surgery, more effective training system has been requested from doctors. By the way, it is important to assess the proficiency level of operating an endoscopic forceps. Then, this study aims to develop an assessment system for the operation skill of endoscopic forceps. In our system, the operation skill of endoscopic forceps is assessed by adding the disturbance to a trainee who is practicing the forceps operation. Three doctors were employed as the test subjects of this study and the differences in their proficiency levels were confirmed in our experiments.

Neuronavigation has been widely used in brain surgery. However, it is known that the effects of brain shift make the navigation inaccurate. Brain shift is the deformation of a patient’s brain caused by removing the cerebrospinal fluid. Intraoperative MRI is one of the techniques to measure the brain shift. However, intraoperative MRI requires large and expensive equipments. Therefore, the method for estimating the brain shift with simple equipment will be useful. We aim to develop a dynamics simulator. In this study, we conducted a dynamics simulation to estimate the brain shift using the particle method and finite element method. In this paper, we describe a framework of MPS-FEM coupled analysis and the results of dynamics simulations.

In neurosurgery, precise and complicated surgical tasks are required to be performed in deep and narrow spaces in the brain, and such surgical tasks are difficult even for skilled surgeons. Many master-slave neurosurgical robots have been developed to assist surgeons; however, previously developed systems are rather bulky and do not have sufficient degrees of freedom (DOFs). Therefore, we are developing a new miniature master-slave neurosurgical robotic system targeted for tasks in deep and narrow spaces of the brain. This robot is equipped with multi-DOF robotic forceps for tasks in deep and narrow spaces. This paper describes the mechanical design and control method of the robot. As a preliminary experiment, a needle insertion task was performed using a model simulating a workspace, showing promising results.

The purpose of this study is to investigate an optimal area to estimate a foot arch deformation based on plantar images. We captured the images of planter skin using a high speed camera and measured longitudinal arch length using 3 dimensional motion analysis system each step at the same time. The planter skin deformations were calculated by each proposed area and compared with the results of 3 dimensional motion analysis system. As a result, using the area which is 0% to 25% and 75% to 100% from the front of sole of the foot except toes as the optimal area showed highest correlation (R=0.67) with the result calculated from 3 dimensional motion capture system among any other areas in this study. This correlation is higher than using the method mentioned in the previous study (R=0.50).

The present paper reports the experimental results of muscle proprioceptive properties in the perception task of reaction forces under slow hand motion. The results demonstrates that human perception accuracy of reaction force changes in both movement direction and arm posture while enhancing as the magnitude of reaction forces becomes smaller: The muscle proprioceptive properties has the spatio-tensional distortion. Finally, biomechanical analysis using human force manipulability successfully explains the experimental findings.

This paper presents a novel evaluation method for an intuitive operability of master-slave surgical robot. Surgical robot is controlled to match the posture of the arm tip between master-slave, however, it’s impossible to match the posture because strict sensing is difficult and the error accumulates during manipulation. The objective is to validate the change of the brain activation against the change of error of posture in the arm tip. In experiment, participants controlled the virtual master-slave simulation. As a result, the brain activity decreased when the error of posture in the arm tip increased. The paper concluded that the 30° would be the acceptable error because when the error was smaller than 30° , the brain activated same as he relaxed.

Our research focuses on effective operation of heterogeneous robotic group that could carry out point-to point navigation in GPS-denied dynamic environment, applying a mixed local and global planning approach, and such instruments as planning in belief space and SLAM. In this paper we introduce our heterogeneous group robots and their modelling in ROS/Gazebo, and briefly describe Homotopy based high level planner solution.

In this study, we aim to achieve an cooperative locomotion of multiple heterogeneous mobile robots. Autonomous rendezvous of an aerial robot and ground robot are proposed. For path planning of each robot, Voronoi Diagram is adopted to express the path and caluculation of edge cost in 2-D space is carried out. Volonoi Diagram is laminated to extend the path planning algorithm to 3-D space. Numerical simulation of rendezvous of two robot is conducted and the validity of proposed method is shown.

This paper proposes a collective movement control method based on both of an internal energy and a phase transition in thermodynamic model for swarm robots, which can move between obstacles with changing an aggregation suitable for arrangement of obstacles in an environment. Swarm robots shape a fixed aggregation by virtual attraction and repulsion forces based on the method, and follow a leader robot with keeping its shape. When the aggregation shape of swarm robots cannot keep to move through narrow spaces surrounded by obstacles, the swarm robots flexibly change the shape according to a shape of the environment based on a partial phase transition provided with directivities, and can continue to move. Simulation results show that swarm robots can move along to the path in an open space, and pass through narrow spaces surrounded by obstacles with changing the aggregation shape according to the environment.

When multiple robots cooperate within same environment, collision avoidance is an essential technology for each robot. In order to achieve effective collision avoidance, it is desired to recognize surrounding robot's motion each other. For this purpose, it is appropriate to exchange motion information by inter-robot communication. We have proposed a local communication system for collision avoidance based on inter-robot communication. By rotating a transmitter and a receiver using a motor, spatially seamless communication toward every direction of robot's surroundings is achieved, and spatial resolution of transmission information which is changed according to transmitting direction is also improved. In this paper, we define transmitting/receiving areas for robot's surroundings and achieve information switching according to transmitting direction. Especially, a settlement of inconsistency on received data is discussed. Finally, we conducted experiments to confirm consistency of received data on a division of transmitting area.

We propose a method of allocating multiple types of tasks to heterogeneous robots based on the theory of comparative advantage for minimizing the makespan (the total length of taskexecuting time). The theory of comparative advantage is an economic theory that maximizes benefit by specialization. Calculation time in the proposed method is negligibly short compared with task-executing time, and it may also be effective for dynamic allocation (e.g., in the real world). We show that our method is also effective in uncertain environments. We also performed two real-world experiments: 1. allocating tidying-up tasks to a wheeled robot and a small humanoid and 2. allocating tasks to a robot and a human.

In multiple robots environment, it is an essential technique that the robots avoid collisions with each other. To achieve efficient collision avoidance, it is desirable that each robot avoids surrounding robots considering not only their positions but also their behaviors. We have developed spatially seamless local communication system in order to exchange behaviors between the robots. This system ensures spatially seamless communicable area towards robot's surroundings by rotating a transmitter and a receiver. However, a bit rate of the communication is insufficient. Although the system has redundant frame structure to detect interference between signals from different transmitters, it causes decrease of the bit rate. In this paper, we aim to improve the bit rate by reducing length of frame of transmission pulse with the interference detection function.

Gravity compensation systems are required for the prototype tests of deployable space structures on the ground. We propose a prototype test system for deployable space structure by using multi robotic units. Each robotic unit is autonomously controlled by using force control. The validity of the proposed system is verified by hardware experiments.

By utilizing the forced entrainment of van der Pol(VDP) equation which is self-excited oscillation system, it is possible to synchronize a periodic input and a controlled object. Further, by the periodic input whose amplitude and phase is modulated by the deviation from the target energy, it is also possible to control the energy of the controlled object. We applied periodic input control to a swing which is parametric excitation system, and showed that it has a characteristic of self-excited oscillation system. Furthermore, we showed that forced entrainment occurs in parametric excitation system that its energy is controlled by periodic input control. In this paper, we indicate that mutual entrainment occurs in two-coupled parametric excitation system.

A cooperative transportation system with three position controlled mobile manipulators is developed using passive joint mechanisms. The installed passive joint mechanisms enable position controlled cooperative transportation with some robots, but they may cause the concentration of the object load on single manipulator because the load applied to each manipulator changes according to the postures of passive joint mechanisms due to the positioning error of mobile platforms. Therefore, a feedback control method of compensating the positioning error of the object is proposed considering the characteristics of the passive joint mechanisms. Then, the effectiveness of the proposed method is verified by experiments.

A multirotor helicopter is a flight robot which can hover, take off, fly, and land in small areas. Recently, multirotor helicopters are getting a lot of attention for information gathering in disaster areas and photogrammetric measuring. They have some drawbacks such as a short duration of flight and a risk of confliction during multi vehicle operation. This paper deals with the formation flight control system for multirotor helicopters that can inspect a wide area in a short time. Practical experiments show that the photogrammetric measuring by using proposed formation flight is more suitable for practical use than the measuring by single vehicle.

Many types of modular robots have been proposed, however the control methods for their transformation have not been established so far. Although equations of motion are necessary for the motion control, it is difficult because modular robots associate with unexpected discontinuity appearing in morphology changes. The objective of this study is to propose a modular robot, in which the contact surfaces between modular robots consist of circular-arc-gears. The geometric restrictions are maintained with a neodymium-magnets force. Here we develop the circular-arc-gear type modular robots equipped with a servo-motor, a micro controller, a battery, and a wireless communication device. Additionally, the experiments are carried out by hardware.

For the field robotics it is necessary to possess the mobility on irregular grounds. One of methods for improvement mobility is that the robot actively constructs environmental conditions, for example, stacking structural objects enable to bridge uneven floors. In this study we focus on what the novel shape of the structural objects is for supporting to move. Particularly, we investigate the ratio of airspace in ragwork of objects which consist of three rigid cuboid bodies. We employed the genetic algorithm to find the optimal shape of structural objects with computer simulations.

A new 2D geometric local interaction rule is developed for decentralised deployment of robot swarms. The objective is to configure a swarm of robots into a lattice of equilateral triangles by local interactions. The local interaction rule configures three robots, from a random initial configuration, into an equilateral triangle whilst minimising the movement distance between configurations.

Performance of swarm systems should be dependent on network structures resulting from various activities of agents. In the present study, we investigated properties of networks appeared through the activities of agents in a swarm system. The system called Ant System imitates a colony of ants in order to solve large scale problems with many agents acting based on local information. We observed the evolution of network structures constructed by the Ant System solving a Travelling Salesman Problem and investigated how they effect on the exploration for better solutions. In the early stage of exploration, nodes with relatively much links changed dynamically. In later stage, network structure showed relatively minor changes, suggesting gradual improvements of in the solution.

We attempted to simulate the swarm behavior of ‘soldier crabs’ Mictyris brevidactylus with a modified Boids model. Interesting periodical movement of the real crab population was not reproduced by our current model. Further investigation on the real crabs are required to improvement our simulation model.

This study proposed a self organizing method to localize self position and to define the final destination for formation control of swarm-robot without any bird's-eye camera or landmark.

In this paper, we propose a cooperative multi-robot control system, operating in dynamic and uncertain environments. We focus on a robust model predictive control (robust MPC) framework that enables robotic agents to operate in uncertain environments. The proposed system includes multiple observation robots that gather information cooperatively as well as a main robot controlled by the robust MPC. Therefore, the system works for not only treating the uncertainty but also decreasing it so that the performance of the robust MPC can be improved. We carry out a Monte Carlo simulation of a multi-robot collision avoidance scenario and analyze a required time for the main robot to arrive at the goal. Simulation results show that the information acquisition by the observation robots enables the main robot to move efficiently and arrive at the goal faster than a case without the observation robots.

Many studies have attempted to create life-like swarm behaviors on computer simulations. The most famous and simple model is Boids proposed by Reynolds where individuals just follow three local rules based on distances and positions to the others. The model can show the realistic and dynamic swarm behaviors but it is not plausible in a sense that all individuals can sense the distances to the others precisely in a real world. We have developed vision-based autonomous robots to form a swarm behavior on 2D environment using a convolutional neural network. This paper extends the model to 3D and investigates how the robots can form a swarm behavior. The results of 3D formation patterns by evolved robots are shown.

Swarm robotics has attracted the attention because it can realize superior functions using simple multiple robots. We have proposed a simple algorithm to realize swarming and following behaviors for omni-directional mobile robots which have only three PSD sensors. Because the following behavior was not observed under a certain condition, we researched the condition by changing the robot parameters in previous study. In this paper, the emergence conditions of leader following behavior are analyzed in more detail through simulation by changing leaderrobot velocity and number of the follower robots.

Swarm robotics is a research area which aims for coordination of large numbers of robots. One of the design methods for swarm robotic systems is the use of evolutionary robotics approach. In evolutionary robotics approach, evolution process often carries out in simulation due to the large amount of time required to obtain the desired collective behavior. The behavior of real robots, however, tends to vary from the one in simulation. This problem is known as the reality gap, which is one of the major issues in evolutionary robotics. This paper focuses on how the individual-level simplicity affects the reality gap of the swarm-level behavior. By changing the resolution capability of sensory inputs, preferable specification of robot's sensors are investigated which is effective to reduce the reality gap.

One approach in swarm robotics is homogeneous system which is embedded with sensing, computing, mobile and communication components. Such a system enhances the potential to be robust, scalable and flexible. In our previous study, we confirmed that Lévy flight is useful for an exploration strategy of swarm robotic network in a target detection problem. This study investigates the robustness of swarm robotic network in the target detection problem, where robustness is the ability to cope with the loss of individuals.

Many current models and theories of controlling flocks depend on metric distance. According to a thesis written by Ballerini considered sterling interaction rule, actual animal collective behavior depends on topological distance. In this paper, we verify the difference of performing by simulating flocking algorithm depend on metric and topological distance.

Two quasi-dynamic walking methods for our working six-legged robot are proposed. This robot can stand up with four lower legs and can use two upper legs as arms; the body is vertical. The robot resembles upright posture of humans. Walk gait moves two pairs of diagonal legs alternately. Parallel gait is a new method specialized for our robot. It makes one pair of two front legs and the other pair of two rear legs. The robot walks by moving these pairs alternately. The experimental results show that the robot can walk by both methods and that parallel gait is faster than walk gait.

A running method for our working six-legged robot is proposed. The robot has two legs at the front side of its body and four legs at the rear side. The four rear legs can kick the ground together, thus generating large propulsive force. Like bound running of quadrupeds, the robot runs by repeating two actions: 1) the robot kicks the ground with the rear legs and jumps forward, and 2) the robot moves its body forward with the front legs and lands the rear legs near the front legs. The robot is redesigned for running, and running poses are determined. Then a method of changing the running speed is proposed. Running performance is evaluated by experiments.

Our four-legged running robot adopts an active suspension type leg module with a linear motion mechanism comprised of a "compression spring" and "DC motor." Because of its simple structure, this robot expresses running motion with a simple physical model. If the robot's dynamic motion is divided into several types, such as fore-leg landing, in the air, and rear-leg landing, and these cases are appropriately switched, a set of these motion equations can precisely write the entire system during running. If we employ a robotic model composed of two masses, the robot while in the air can be described as the free motion of a two-mass system, and the robot while landing can be described as a double pendulum. Our study confirms that it is possible to express the running of the robot with these models, based on the experiments with simulation and the robot.

Four-legged animals move with high speed and high efficiency by selecting their gait according to the terrain. Our aim is to reproduce the features of a four-legged animal in a robot. To reproduce the legs of a four-legged animal, we adopt as a leg module an active suspension with a linear motion mechanism comprised of a compression spring and a DC motor. We are studying high-speed running of a four-legged running robot with an active suspension mechanism. It is necessary to efficiently reproduce an animal’s leg motion in order to increase the moving speed of the robot. In this study, we examined the gallop gait, which is the fastest, in an experiment targeting the generation of a stable gallop gait. As a result, a stable gallop gait was obtained, and we found there is asymmetry of left and right leg motion.

Robots have recently become more active participants in human life. They are being studied and developed actively all over the world, and are designed for use in various areas. Multi-legged robots, such as those with six legs, are highly adaptable to various environments and terrains. We focused on a robot's ability to walk in mud, as such walking is particularly difficult, especially on uneven surfaces. Based on the results of our past walking experiment, from which we determined that walking instability is due to a loss of balance caused by decreased power and instability of the support legs in mud, we aimed to achieve stable walking ability by center of gravity control use the support legs.

This research presents the development of a six-legged walking robot namely Giacometti Robot and its leg design mechanism using thin soft actuator. The robot is aimed to have long, light and thin legs taking concept from Giacometti's sculptural technique. The robot prototype has 12 DOF with 2 DOF at each leg and was tested with basic walking locomotion. Result shows the robot successfully demonstrates basic walking motion.