This paper presents a mechanism for the robot moving inside of pipelines. The mechanism is composed of the 2-2D differential gear mechanism, the active adhesion mechanism, and the rescue mechanism. The 2-2D differential gear mechanism is designed to be driven with single actuator at any elbow type pipelines without any additional control efforts. The active adhesion mechanism is for providing sufficient adhesion forces of the robot on climbing over the pipelines against the gravity. In addition the rescue mechanism is designed for retrieving the robot safely in emergency situation. In this paper, three proposed mechanisms are explained in details and their effectiveness is experimentally demonstrated.

In this paper, a back-drivable joint mechanism for an in-pipe robot is presented. The joint mechanism consists of 2-pitch and 1-roll joint. The back-drivability of the joint mechanism is realized by using a ball-screw and a steel wire rope. When the in-pipe robot with the back-drivable joint mechanism passes through pipeline elements except the miter and the branch, the control of the joint mechanism is not required. In addition, a rescue mechanism is not needed in case of emergency such as the loss of power, communication and control. Besides, the 2-pitch joint of this joint module assists the in-pipe robot to pass through the miter and the branch safely and quickly. Finally, the performance of back-drivable joint module is experimentally validated.

This paper introduces a novel robot which is able to climb hanger cables of long span suspension bridges. The robot has been developed for inspection purpose, and it can help us remotely inspect the state of cables by using cameras and Non-Destructive Testing (NDT) devices. The robot consists of two traction modules, two sub modules, and an adhesion mechanism. The unique design of the traction module ensures the stable movement of the robot on the twisted surface of the hanger cable. In this paper, we describe the structure and environmental situation of hanger cables and the mechanisms of the robot. Also, the results of experiments in the indoor and outdoor environments are included.

To deploy an untethered robot inside pipelines without any external assistance, it is prerequisite to recognize the pipeline elements such as straight pipeline, elbow, T-branch, and miter. This paper presents a method of recognizing pipeline elements using PSD(Position Sensitive Device) sensors. It is easy to implement, but help us collect accurate information necessary for navigating inside pipelines without heavy computation. The method is composed of three parts, which is the method for distinguishing T-branch and miter, searching the direction in T-branch and elbow, and determining the types of pipeline element, respectively. The design for the PSD sensor suite is presented and the algorithm for recognition procedures are addressed. The sensor suite is implemented in an in-pipe robot, called MRINSPECT VI, and its performances are validated.

In this paper, novel mechanisms for an in-pipe robot are presented. Multi-axial differential gear mechanism is designed to be driven with only single motor at any elbow-pipe without additional control efforts while all three wheels keep driving power. Brake system was added to prevent slip of wheel. Active wall pressing mechanism allows controlling the contact forces. And additional rescue mechanism is designed for emergency situation. Lastly, their effectiveness is experimentally validated.

This paper presents a mechanism for an in-pipe robot, called MRINSPECT VI (Multifunctional Robotic crawler for In-pipe inspection VI), which is under development for the inspection of gas pipelines with 150mm inside diameter. The mechanism is composed of multi-axial differential gear mechanism, wall pressing one, and driven by single motor. It is designed to adapt to the varying inside geometries of pipelines such as elbows by modulating the velocities of active wheels mechanically without any control effort. In this paper, the design features of the mechanism are detailed and its effectiveness is experimentally validated.

Improvement of the adaptability of a quadruped robot in rough terrain is studied in this paper. First, the position and posture of the body of the robot are adjusted to maximize the number of choices for foot placement of the next swing leg. The more choices the robot has to select the next suitable foothold, the better it will be to cope with rough terrain. Second, an effective foothold search algorithm is developed. The foothold search algorithm not only tries to find a valid foothold but also tries to maintain high adaptability of the robot. For implementing the algorithm, some new concepts such as potential swing direction, complementary kinematic margin and elliptical set of candidate footholds are also proposed. The effectiveness of this procedure in improving the adaptability of a quadruped robot moving in challenging terrain is verified in both simulation and experiment.

In this paper, we propose a method of sensing outdoor environments for a walking and climbing robot. The proposed method ensures the realtime perception of the surface geometry by integrating a range and a gyroscope with a novel arrangement of the sensors. In addition, a gait planning algorithm based on the sensing method is presented. The algorithm runs fast since it is simple, and the rich information from the sensing system helps the robot overcome the real environment, even an extremely complex one. The sensing system is implemented in a quadruped walking robot, called MRWALLSPECT IV and its effectiveness is proved experimentally.