This article presents GraphSLAM, a unifying algorithm for the offline SLAM problem. GraphSLAM is closely related to a recent sequence of research papers on applying optimization techniques to SLAM problems. It transforms the SLAM posterior into a graphical network, representing the log-likelihood of the data. It then reduces this graph using variable elimination techniques, arriving at a lower-dimensional problems that is then solved using conventional optimization techniques. As a result, GraphSLAM can generate maps with 108 or more features. The paper discusses a greedy algorithm for data association, and presents results for SLAM in urban environments with occasional GPS measurements.

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The Graph SLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures

Pipelines for the urban gas-supply system require a robot possessing outstanding mobility and advanced control algorithms, since they are configured with various pipeline elements, such as straight pipelines, elbows, and branches. We present a comprehensive work for moving inside underground urban gas pipelines with a miniature differential-drive in-pipe robot, called the Multifunctional Robot for IN-pipe inSPECTion (MRINSPECT) IV. MRINSPECT IV has been developed for the inspection of urban gas pipelines with a nominal 4-in inside diameter. The mechanism for steering with differential-drive wheels, arranged three-dimensionally, allows it to easily adapt to most of the existing configurations of pipelines, as well as providing excellent mobility during navigation. After carrying out analysis for fittings in pipelines, mathematical descriptions of their geometries are presented, which make it possible to estimate the movement patterns of the robot while passing through the fittings. Also, we propose a method of controlling the robot by modulating speeds of driving wheels that is applicable without sophisticated sensory information. To confirm the effectiveness of the proposed method, experiments are performed, and supplementary considerations on the design of the in-pipe robot are discussed.

Differential-drive in-pipe robot for moving inside urban gas pipelines

Although the off-road mobility characteristics of wheeled or tracked vehicles are generally recognized as being inferior to those of man and cursorial animals, the complexity of the joint-coordination control problem has thus far frustrated attempts to achieve improved vehicular terrain adaptability through the application of legged locomotion concepts. Nevertheless, the evident superiority of biological systems in this regard has motivated a number of theoretical studies over the past decade which have now reached a state of maturity sufficient to permit the construction of experimental computer-controlled adaptive walking machines. At least two such vehicles are known to have recently demonstrated legged locomotion over smooth hard-surfaced terrain. This paper is concerned with an extension of the present theory of limb coordination for such machines to the case in which the terrain includes regions not suitable for weight-bearing and which must consequently be avoided by the control computer in deciding when and where to successively place the feet of the vehicle. The paper includes a complete problem formalization, a heuristic algorithm for solution of the problem thus posed, and a preliminary evaluation of the proposed algorithm in terms of a computer simulation study.

Adaptive Locomition of a Multilegged Robot over Rough Terrain

In this paper, we address the problem of creating an objective benchmark for evaluating SLAM approaches. We propose a framework for analyzing the results of a SLAM approach based on a metric for measuring the error of the corrected trajectory. This metric uses only relative relations between poses and does not rely on a global reference frame. This overcomes serious shortcomings of approaches using a global reference frame to compute the error. Our method furthermore allows us to compare SLAM approaches that use different estimation techniques or different sensor modalities since all computations are made based on the corrected trajectory of the robot.

We provide sets of relative relations needed to compute our metric for an extensive set of datasets frequently used in the robotics community. The relations have been obtained by manually matching laser-range observations to avoid the errors caused by matching algorithms. Our benchmark framework allows the user to easily analyze and objectively compare different SLAM approaches.

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On measuring the accuracy of SLAM algorithms

Application of robotics in offshore oil and gas industry- A review Part II

This paper presents an in-pipe robot, called MRINSPECT V (Multifunctional Robotic crawler for In-pipe inSPECTion V), which is under development for the inspection of pipelines with a nominal 8-inch inside diameter To travel freely in every pipeline element, the robot adopts a differential driving mechanism that we have developed Furthermore, by introducing clutches in transmitting driving power to the wheels, MRINSPECT V is able to select the suitable driving method according to the shape of the pipeline and save the energy to drive in pipelines In this paper, the critical points in the design and construction of the proposed robot are described with the preliminary results that yield good mobility and increased efficiency

In-pipe robot based on selective drive mechanism

Pipelines which are tools for transporting oils, gases and other fluids such as chemicals, have been employed as major utilities in a number of countries for long time. Recently, many troubles occur in pipelines, and most of them are caused by aging, corrosion, cracks, and mechanical damages from the third parties. Even though lasting activities for maintenance are strongly demanded, they need enormous budgets that may not be easily handled by related industries. Currently, the applications of robots for the maintenance of the pipeline utilities are considered as one of the most attractive solutions available. In-pipe robots which have the long history of development in robotics can be classified into several elementary forms according to moving patterns, as shown in Fig. 1, although most of them have been designed depending upon specific applications.

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In-pipe Robot with Active Steering Capability for Moving Inside of Pipelines

In this paper we present an in-pipe robot, called MRINSPECT V (Multifunctional Robotic crawler for In-pipe inSPECTion V), which is under development for the inspection of pipelines with a nominal 8-inch inside diameter. To travel freely in every pipeline element, the robot adopts a differential driving mechanism that we have developed. Furthermore, by introducing clutches in transmitting driving power to the wheels, MRINSPECT V is able to select the suitable driving method according to the shape of the pipeline and save the energy to drive in pipelines. The robot aiming for autonomous navigation is configured with four modules serially connected. Two active driving modules are located in front and rear of the system, respectively. Passive modules are linked between the driving modules. This module-based robot can fit to narrow and winding pipelines by using the novel mechanism such as the specially designed module-joints. In this paper, the critical points in the design and construction of the proposed robot are described with the preliminary results of experiments that yield good mobility and increased efficiency.

Modularized in-pipe robot capable of selective navigation Inside of pipelines

In the previous reports (2001), we presented a miniature inpipe robot called MRINSPECT (Multifunctional Robotic crawler for INpipe inSPECTion) IV which has been developed for the inspection of urban gas pipelines with a nominal 4-inch inside diameter Its steering capability with three-dimensional differentially driven method provides the outstanding mobility for navigation and the new mechanism for steering can easily adjust itself to most of pipelines or fitting, in which other former inpipe robots can hardly travel as ever In this paper, we present the strategy and the critical points established on using the speed modulation for the navigation in elbows and branches The analysis for the navigation inside fittings and curved pipelines is given in detail and it is addressed how to compute the speeds of the independent wheels for the differential drive in elbows and branches

Se-gon Roh

Papers

Differential-drive in-pipe robot for moving inside urban gas pipelines

In-pipe robot based on selective drive mechanism

In-pipe Robot with Active Steering Capability for Moving Inside of Pipelines

Modularized in-pipe robot capable of selective navigation Inside of pipelines

Strategy for navigation inside pipelines with differential-drive inpipe robot