Although modular robots with snake-like structures have been proposed in previous studies, very few have achieved separation and docking without direct human intervention. Based on prior research on conventional snake robots and modular robots, we propose a modular snake robot composed of a minimum module consisting of five links and four joints. This robot is capable of rotating and translating in a two-dimensional plane even as a single module. Each module is equipped with a unique detachable and dockable structure using magnets and mechanical hooks, and reconfiguration between modules is realized through these motions. Through field experiments, we verified the reproducibility of the detachment and docking actions, as well as the locomotion capability of each module in the detached state.

We have developed a CT guided needle puncture robot (Zerobot) to assist in interventional radiology surgery. Currently, Zerobot is operated remotely, and the next goal is to perform automatic needle puncture surgery. There is a challenge that automatic detection of puncture needle from CT images for first step of automatic puncture surgery. Because there is the case that the form of puncture needle is curved, it is necessary to detect the needle from CT image instead of estimating the needle position from arm of Zerobot. First, the method detects ROI with ResNet. Next, difference of the CT value is calculated for each pixel in the ROI, and a linear approximation is performed for to detect the needle shape. Images from animal experiments were used to evaluate the learner and image processing. We confirmed that the proposed method can detect needles in a single image and in multiple images.

There is minimally invasive method called Interventional Radiology (IR) that achieves an operation by using diagnostic imaging equipment such as Computed Tomography (CT). IR has advantages that it is a minimally invasive method and it is applied widely such as lung cancer treatment, liver cancer treatment, biopsy, and so on. However, it has a problem that doctors are exposed by X-ray due to a procedure in the vicinity of the CT gantry. To solve this problem, we have developed a robot so we calling “Zerobot”. Zerobot has six DOF and controlled remotely. We previously conducted animal experiment using a rabbit to evaluate Zerobot. As a result, percutaneous puncture was impossible without epidermis cutting. Therefore, we developed a new function called instantaneously puncture that can achieve high speed and short stroke puncture like a human operator. In this paper, overview of Zerobot is described first. Then, measurement of puncture speed of a human operator is described. Furthermore, design and system structure of instantaneously puncture system is described. Finally, we present results of animal experiment using the instantaneously puncture system.

In this paper, we develop a new type of snake-like robot using screw-drive units that are connected by active joints. The screw-drive units enable the robot to generate propulsion on any side of the body in contact with environments. Another feature of this robot is the omnidirectional mobility by combinations of screws' angular velocities. We also derive a kinematic model and apply it to trajectory tracking control. Furthermore, we design a front-unit-following controller, which is suitable for manual operations. In this control system, operators are required to command only one unit in the front; then, commands for the rest of the units are automatically calculated to track the path of the preceding units. Asymptotic convergence of the tracking error of the front-unit-following controller is analyzed based on a Lyapunov approach for the case of constant curvature. The effectiveness of the control method is demonstrated by numerical examples and experiments.

Recently, multiple locomotion gaits of snake have been realized by snake robots. However, previous locomotion gaits are mainly limited on two-dimensional plane. In this study, we make a snake robot that can move in three-dimensional space by connecting several units serially. The each unit is composed by assembling one pitch axis and one yaw axis, and it can have two passive wheels. We realize previously achieved basic locomotion gaits and simple cylinder climbing locomotion. In addition, we also realize cylinder climbing locomotion with helical form by the snake robot using mathematical continuum model.

This paper presents a path-tracking control method for a snake-like robot using screw drive mechanism. The operators are required to command only one unit in the head, then commands for the rest of the units are automatically calculated to track the path of the preceding units. Although the velocity commands for exact path tracking can be calculated using past command signals due to the omni-directional property of the robot, a simpler control law without using past signals is adopted from the implementation viewpoint. Asymptotic tracking error is investigated based on a Lyapunov approach for the case of a constant curvature. Furthermore, the effectiveness of the proposed method is investigated by computer simulations and laboratory experiments.

In this paper, we develop a prototype of a new snake-like robot using the screw drive mechanism, and design a control system design for trajectory tracking. First, we explain the outline of the snake-like robot using the screw drive units and joint units, as well as the principle of the screw drive mechanism. Next, in order to achieve the trajectory tracking of the robot, we derive a kinematic model. Finally, the validity of the derived model and the effectiveness of the proposed control system are demonstrated by simulations and experiments.

To search victims in the narrow space at the disaster site, we have developed the snake-like rescue robot called "KOHGA". The robot is constructed by connecting multiple crawler vehicles serially by active joints. KOHGA has a problem that obstacles are caught to the joints and then the robot is stuck. To solve this problem, we developed an unit assembled robot "KOHGA2". It can be rearranged. The robot can swing crawler-arms and avoid the stuck. In this paper, we report the construction of the hardware and the control system of KOHGA2, the basic mobility performance, and the stuck avoidance strategy.

Our research perspective is to develop mechanisms for gathering information efficiently in disaster sites. Ideally this requires mechanisms with capabilities of flexible, on-site, adaptation of the overall shape and of the locomotion strategy to unknown and unstable environments. We have been developing three-legged modular robots which can be interconnected to cooperatively achieve multiple locomotion modes and collaboratively perform tasks that cannot be done by a single module. In this paper, we report the development of experimental modular robots and experimentations with their cooperative activities which evolve out of their various inter-connectivity options.

In this paper we report the development of a new rescue robot platform. The robot is constructed by connecting multiple crawler vehicles serially, resulting a long and thin structure so that it can enter narrow space. The units are connected by 2-DOF active joints and 3-DOF passive joints, so that the robot can have both the capability to climb over obstacles as well as adaptation to irregular surfaces. Basic steering and experiments for the robot are also shown.

Robots are useful for search and detection missions for trapped victims after disasters due to their abilities enter places where human rescuers cannot go without risking their own lives. We have experienced and found much knowledge about rescue robots while participating in the RoboCup Rescue Competitions. In this paper we introduce examples of "effective multiple robot cooperative activities" and "a study of the number of robots and operators in a multiple robot team" from our experiences in these competitions.

Reinforcement learning is very effective for robot learning. It is because it does not need prior knowledge and has higher capability of reactive and adaptive behaviors. In our previous works, we proposed new reinforce learning algorithm: "Q-learning with dynamic structuring of exploration space based on genetic algorithm (QDSEGA)". It is designed for complicated systems with large action-state space like a robot with many redundant degrees of freedom. However the application of QDSEGA is restricted to static systems. A snake-like robot has many redundant degrees of freedom and the dynamics of the system are very important to complete the locomotion task. So application of usual reinforcement learning is very difficult. In this paper, we extend layered structure of QDSEGA so that it becomes possible to apply it to real robots that have complexities and dynamics. We apply it to acquisition of locomotion pattern of the snake-like robot and demonstrate the effectiveness and the validity of QDSEGA with the extended layered structure by simulation and experiment.

We present a type of locomotion mode, path planning of shape transition, and design and implementation of a 3-dimensional hyper-redundant snake-like robot. First we explain the multiple locomotion modes, for example ring mode, inching mode, bridge mode, and so on. We propose a new type of locomotion "twisting mode" and analyze the principle of the locomotion based on statics. Next, the motion planning using genetic algorithm for transition of locomotion modes is explained and simulation results for the GA research is shown. Finally, we explain the designed prototype system and experimental results are shown.