In a recent article published in the journal Biomimetic Intelligence and Robotics, researchers introduced a novel helical gait for snake robots that can perform three-dimensional (3D) spiral motions and inspect the inner walls of pipelines more effectively and comprehensively. Their primary goal was to address the critical challenge of precisely determining the coordinates and orientations of pipeline leaks, a longstanding safety concern in the industry.
Study: Novel Helical Gait for Snake Robots in Pipeline Inspection. Image Credit: FOTOGRIN/Shutterstock.com
Background
Pipeline transportation is vital across various sectors, including oil, gas, water supply, drainage, and heating systems. However, these pipelines are susceptible to environmental factors that may cause cracks and defects over time, potentially leading to catastrophic incidents. Consequently, regular inspection and maintenance of pipeline structures are crucial. Current inspection methods often struggle to pinpoint the exact locations and orientations of pipeline leaks, posing significant safety risks.
Snake robots, composed of multiple joint modules, offer diverse motion patterns such as meandering, traveling waves, and helical movements. This versatility enables them to adapt to varying pipe diameters and navigate through complex structures and obstacles efficiently. Additionally, these robots can be equipped with cameras and sensors, allowing them to capture real-time images and data of the pipeline's interior walls.
About the Research
In this study, the authors developed a helical gait specifically tailored for inspecting the inner walls of gas pipelines. They utilized the backbone curve method, which defines a continuous curve's shape through curvature and torsion parameters. This technique facilitates the creation of a gait capable of performing complex 3D spiral motions. Additionally, it enables the precise calculation of joint angles in a snake robot with a discrete modular structure, ensuring that the robot accurately follows the intended curve.
The researchers started by reviewing the existing literature on the helical gait of snake robots. They identified a significant research gap: most studies have concentrated on helical motions on the outer surface of cylinders, with few addressing the development of helical motions for inspecting the interiors of pipelines. To address this gap, they proposed a new helical motion model capable of generating both cylindrical and conical spiral motions within pipes.
The paper introduces the structural design of a snake robot consisting of 21 joint modules connected orthogonally. These modules are engineered to facilitate 3D spiral motion within gas pipelines with diameters ranging from 200 mm to 500 mm. The head joint is equipped with cameras and sensors to aid in inspection tasks.
To control the snake robot's motion, the authors developed functions using two methods: the gait equation method and the backbone curve method. The gait equation method is used to generate simple two-dimensional (2D) motions, such as meandering and traveling wave movements. In contrast, the backbone curve method is employed to produce complex 3D motions, including cylindrical and conical spiral movements. The study also derived mathematical models and detailed the specific parameters crucial for executing these helical motions.
Research Findings
The authors carried out both physical and simulation experiments to validate the feasibility and effectiveness of the proposed helical gait. Physical experiments showed that the snake robot could successfully perform meandering and traveling wave motions within a transparent pipe of 300 mm in diameter.
Simulation experiments demonstrated that the snake robot could execute cylindrical and conical spiral motions in a virtual pipe of the same diameter. These experiments facilitated a comparison of the advantages and disadvantages of the different helical motions.
The findings revealed that cylindrical spiral motion enables the snake robot to adhere closely to the inner wall of the pipe, which is beneficial for thorough surface inspection. However, this motion restricts the inspection space and limits the robot's travel speed. Conversely, conical spiral motion allows the snake robot to partially detach from the pipe's inner wall, thereby expanding the inspection space and increasing travel speed. Furthermore, this motion positions the head joint closer to the pipe’s centerline, enhancing image quality and providing a more comprehensive panoramic view.
Applications
The proposed helical gait holds significant potential for applications across various sectors that require pipeline inspection and maintenance, such as oil, gas, water supply, drainage, and heating systems. This gait enables snake robots to adapt to varying pipe diameters and structures, allowing them to gather comprehensive and accurate data about the pipeline's inner wall.
Furthermore, the versatility of the helical gait extends to performing secondary tasks, such as clearing sediment or patching cracks. This is achieved by equipping the snake robots with specialized tools or a reamer in place of the standard head joint, enhancing their utility and effectiveness in maintaining pipeline integrity.
Conclusion
In summary, the proposed helical gait-based snake robot proved effective for comprehensively performing 3D spiral motion inside pipelines and inspecting their inner wall for defects. Future work should focus on enhancing the stability and robustness of the helical gait through the design of more effective feedback regulators for traveling wave and helical motions, improving the hardware and software of the snake robot prototype, and testing the robot in real-world pipeline environments.
Journal Reference
Liu, J., Li, M., Wang, Y., Zhao, D., Deng, R. Multi-gait snake robot for inspecting inner wall of a pipeline. Biomimetic Intelligence and Robotics, 2024, 4, 100156. DOI: 10.1016/j.birob.2024.100156, https://www.sciencedirect.com/science/article/pii/S2667379724000147
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Article Revisions
- Jul 10 2024 - Title changed from "Novel Helical Gait for Snake Robots Enhances Pipeline Inspection" to "Snake Robots Revolutionize Pipeline Inspections"