A new type of mobile pipeline maintenance robot has been designed to clarify the feasibility of lazy tongs mechanism for adaptation to various size pipelines. The robot basically consists of three modules with two joints between modules and can move straight and spirally along the surface of pipeline. The robot can change its arm length in order to move on the pipeline of various size from 25 A to 100 A, and pass over obstacles such as reducer, diffuser, flange and other plant equipment. The control of the robot is so complicated that the modified dual control mode is introduced using the coordinate transformation matrix. By calculating the position and attitude of the robot under the control mode, the manoeuvrability of passing over a reducer is shown with experimental results.

Deals with a computer simulation study of the cooperative behavior of multirobots for investigating the characteristics of swarm intelligence generated by multirobot system. Individual robots in the multirobot system are equipped with low-level intelligence to detect obstacles, steer, proceed, and undertake a hello-call communication. This paper first clarifies the characteristics of multirobot behavior under free traveling without hello-call communication and then the characteristics of hello-call communication with respect to message transmission power over whole member robots. Introducing a marker robot to the multi-robot system, the authors find that the multirobot system can generate a communication chain to be used for searching the route to their goal. They demonstrate the swarm intelligence of the multirobots system in the case of route-searching and show the effects of robot population on the swarm intelligence.

The basic idea of a new type of actuator based on a shape memory alloy (SMA) and its application to underwater mobile robots are presented. The actuator consists of a multimode SMA, so that any shape can be produced as the synthesized sum of excited modes. Thus, the actuator shows the characteristics of distributed-parameter-type actuators with a specified number of modes. A flat-belt-type SMA is employed, and its bending characteristics are examined. A method of waveform synthesis is presented. Applying the proposed distributed actuators to the underwater mobile robot, a fish-fin-like mechanism is shown to obtain thrust forces in the water. The shape of the actuator was shown experimentally to be similar to the computed shape. As a result, the distributed actuator shows the possibility of application to distributed-parameter shape control.>

The authors describe rubber actuators using a hydrogen storage alloy for an in-pipe inspection robot, which is capable of moving inside pipelines with inner diameter as small as 2 in. Rubber actuators with both stretching and shrinking capability are shown for realization of such a robot. The proposed robot uses twelve actuators, including six kinds of independently controlled actuators, so that it si more flexible and adaptable in motion: it can move in an inchworm mode through pipelines, it is adaptive for changing pipe diameters, and it is able to pass over the L- and T-joints of pipelines. The robot actuators can initially be achieved and prepared by hydrogen gas. The control method is also shown, with a T-joint movement as an example.>

A new type of mobile robots with the inch worm mechanism is presented in this paper for inspecting pipelines from the outside of pipe surfaces under hostile environments. This robot, Mark III, is made after the successful investigation of the prototypes, Mark I and II, which can pass over obstacles on pipelines, such as flanges and T-joints and others. Newly developed robot, Mark III, can move vertically along the pipeline and move to the adjacent pipeline for the inspection. The sensors, infra ray proximity sensor and ultra sonic sensors and others, are installed to detect these obstacles and can move autonomously controlled by the microprocessor. The control method of this robot can be carried out by the dual control mode proposed in this paper.