Robotic sensor networks provide an effective approach for underground pipeline inspection. Such networks are comprised of sensor nodes (SNs) and relay nodes (RNs) carried by robots for information sensing and communication, and are able to perform accurate and realtime inspection, especially in adverse environments. SN localization is critical in such networks because localization results can be used not only for locating and pinpointing leaks, but also for maneuvering mobile SNs in a pipeline of complex configuration. However, both the underground operational environment and the limited resources of the SNs pose significant challenges for SN localization. This paper presents algorithms for SN localization in robotic sensor networks for underground pipeline inspection. Specifically, self-localization of underground in-pipe SNs were investigated by taking into account SN movement dynamics, and using the measurements of the SN's velocity and the received signal strength (RSS) of the radio signal from aboveground RNs. Depending on the availability of the RSS at the SN, different localization algorithms based on the Kalman filter are proposed for different scenarios. Simulation results show the efficacy of the proposed algorithms. The framework also provides insight into the design of robotic sensor networks for the inspection and maintenance of other types of pipeline systems, such as oil and gas pipelines.

Autonomous underwater robots provide opportunities to perform missions in confined environments such as water pipe networks. They can carry sensors in these pipes and perform tasks such as mapping and inspection. Those robots must have a high level of maneuverability in order to navigate through complex networks of pipes with irregularities due to rust and calcite deposition. We propose a fully integrated, untethered robot capable of carrying sensors and maneuver into water pipe networks. The objective of this paper is to present (i) the optimal shape design and (ii) a propulsion system selection and sizing procedure for such robots. A prototype is built to demonstrate the basic elements of maneuverability, including following straight lines and making sharp turns.

In this work we present a new in-pipe leak detection robot, the MIT Leak Detector. The system performs autonomous leak detection in gas pipes in a reliable and robust fashion. Detection in based on the presence of a pressure gradient in the neighborhood of the leak. As the MIT Leak Detector travels through pipes, it picks up the pressure gradient in case of leaks via a carefully designed detector. In this work we demonstrate the performance of the system in a lab setup, which consists of 100mm ID pipes containing pressurized air.

Leakage is the most important factor for unaccounted losses in any pipe network around the world. Most state of the art leak detection systems have limited applicability, lack in reliability and depend on user experience for data extraction. This paper is about a novel system for robotic pipe integrity inspection. Unlike existing systems, detection in based on the presence of a pressure gradient in the neighborhood of a leak. This phenomenon is translated into force measurements via a specially designed and instrumented mechanical embodiment (detector). In this paper an analytic dynamic model of the robotic detector is derived and studied. A prototype is built and the main concepts are validated via experiments.

Wireless sensor networks (WSNs) provide an effective approach for underground pipeline inspection. Such WSNs comprise sensor nodes (SNs) and relay nodes (RNs) for information sensing and communication. WSNs can perform accurate and realtime inspection, especially in adverse environments. However, transmitting information between underground and aboveground nodes is very challenging. First, in-pipe SNs conducting controlled maneuvers underground are mobile. Second, SNs need to transmit the information wirelessly to aboveground base stations (BSs). In addition, radio propagation is complex because radio waves travel in a multi-medium environment. Finally, the SNs have limited energy supply. Therefore, proper deployment of a WSN is critical to providing reliable communications and efficient inspection. This paper presents a channel-aware methodology for deploying aboveground RNs in WSNs for underground pipeline inspection. Specifically, first, the paper provides a path loss model for radio propagation over multiple transmission media. Then, based on the path loss model a method is developed for optimum placement of the RNs so as to minimize the energy use of SNs and allow reliable communications. This method takes into account characteristics of the wireless channels, power consumption constraint, pipeline coverage requirement, and the limit of the number of the RNs. We provide an algorithm for optimization of RN placement and SN's power consumption. Simulation results show the efficacy of the proposed framework.

In-pipe wheeled robots require friction on the wheels to maintain traction. Ability to vary this friction is highly desirable but conventionally used linkage mechanism is not suitable for it. This paper presents a novel mechanism generating adjustable friction with minimal energy consumption for in-pipe robots. The mechanism uses permanent magnets to achieve the objective. An appropriate model for the system is also presented and discussed. The paper identifies the important design parameters, and more importantly establishes the relation between the design parameters and the system's performance. In addition, a prototype of the mechanism was designed, fabricated and tested for validation.