Underground water pipes are important to any country's infrastructure. Overtime, the metallic pipes are prone to corrosion, which can lead to water leakage and pipe bursts. In order to prolong the service life of those assets, water utilities in Australia apply protective pipe linings. Long-term monitoring and timely intervention are crucial for maintaining those lining assets. However, the water utilities do not possess the comprehensive technology to achieve it. The main reasons for lacking such technology are the unavailability of sensors and accurate robot localization technologies. Feature based localization methods such as SLAM has limited use as the application of liners alters the features and the environment. Encoder based localization is not accurate enough to observe the evolution of defects over a long period of time requiring unique defect correspondence. This motivates us to explore accurate contact-less and wireless based localization methods. We propose a cost-effective localization method using UHF-RFID signals for robot localization inside pipelines based on Gaussian process combined particle filter. Experiments carried out in field extracted pipe samples from the Sydney water pipe network show that using the RSSI and Phase data together in the measurement model with particle filter algorithm improves the localization accuracy up to 15 centimeters precision.
Asset management of a marine port or terminal requires inspection of the asset components below the water surface, at the water surface line and above the water surface. In order to determine asset health, high fidelity, multi-modal data is captured remotely using robotics, and subsequently analyzed. This facilitates the production of prioritized actionable insights to be produced. These insights can be scheduled as maintenance works. This paper outlines a novel multimodal inspection system that was deployed at a port to facilitate its remote inspection. Two inspections are detailed in this paper, with differing inspection requirements and constraints. The inspection operation can be broken down into multiple components, an underwater scan of the port, a water-surface scan, a ground level scan and an aerial scan. The Port Asset required the inspection of the wharf and quay walls. The Marine Terminal Asset required inspection of the complex pipework. The data collected from the different modalities were represented in the 3D space. The alignment of the different modalities could then be done in this representation. For the Port Asset, where multibeam sonar maps were collected, the difficulty in alignment of the different modalities is apparent due to no shared points below and under-water, which requires estimation using extended features as landmarks. There also exists slight warping between the data that must need localized scaling for certain sections, which may be done using local submaps and scaling. For the Marine Terminal Asset, artificial markers are used to allow scaling of the drone captured photogrammetry. High levels of coverage from the multiple views of the asset from different data collection strategies allowed the complex pipework to be well mapped, with further insights from the co-registered imagery. The novel information described in this paper is the unique combination of different modalities for a broadscale port inspection, with point clouds from sonar, lidar, photogrammetry and imagery, in a combined reference frame which acts as a digital twin for the port. This also allows unique insights, such as the exact context and magnitude of faults in the port environment, to allow corrective works to be targeted correctly.
This paper outlines an optical stereo photogrammetric imaging system, called the Lantern Eye Air (LEA), for inspecting the mooring chain above the water in the area known as the splash zone. The system is mounted and deployed by a Rope Access Technician (RAT), and achieves data collection in this difficult to access region for subsequent 3D reconstruction and measurements for inspection. Typically, splash zone mooring chain inspections are carried out using mechanical calipers which are difficult to deploy, provide measurements at discrete locations only and are dependent on the proficiency and judgement of the operator on the field. The LEA system overcomes these problems, providing objective, accurate and repeatable measurements based on reconstructed photorealistic 3D models. Imagery of the chain links is captured systematically which was used to generate 3D reconstructions and establish measurements of bar diameter and inter-grip length. A splash zone inspection was undertaken on an offshore platform. The 3D metrology bar diameter measurements were within 1.7% of caliper measurements based on 2σ (95% confidence). Similarly, the 3D metrology inter-grip length measurements were within 0.9% of caliper measurements based on 2σ (95% confidence). Application of a systematic validation procedure following the inspection placed the expected uncertainty of measurements at the 1% range. Similarly, the uncertainty in caliper measurements has been estimated to be 2% based on the use of a standard handheld caliper and measurement procedure laid out in the ABS Guide for the Certification of Offshore Mooring Chain and the 2020 Life Extension Mooring Platform Chain Inspection. Considering these uncertainty bounds, the 3D metrology measurements can also be deemed consistent with the ground truth dimensions. Based on the results, the LEA and 3D metrology measurements are consistent with current techniques and provide a more systematic and repeatable basis for mooring chain inspection and measurement in the splash zone. This is anticipated to improve the consistency and comparability of inspections and will enable precise change tracking between inspections.
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