How Mofopefoluwa Aluko Developed a Snake-Like Robot for Pipeline Inspection

By Abigail Joseph · · Robotics

How Mofopefoluwa Aluko Developed a Snake-Like Robot for Pipeline Inspection

The way pipelines are built enables them to move fluids over long distances, but their maintenance is a different challenge altogether. Fluids like oil, water…

The way pipelines are built enables them to move fluids over long distances, but their maintenance is a different challenge altogether. Fluids like oil, water and gas can run underground in these pipelines or through areas where direct access is difficult. Inside the pipes, corrosion, cracks, dents, deposits and other defects can develop without being visible from the outside, making regular inspection important for identifying problems before they escalate. In-pipe inspection robots are one of the technologies being developed to tackle the challenge, with different designs and forms of locomotion. Mofopefoluwa Aluko, a mechatronics engineering student at Landmark University and robotics trainee at Robotics and Artificial Intelligence Nigeria (RAIN), decided to tackle the industrial problem with a different kind of machine. He developed a segmented robot designed to move like a snake.

Aluko’s project, listed by RAIN as a Kinematic Snake-like Robot for Pipeline Inspection, shed more light on whether the movement pattern of a snake could be replicated mechanically using servo motors, an Arduino-based control system and mathematical wave patterns. This resulted in a working prototype that showed a coordinated snake-like movement and provided a basis for further development toward applications such as pipeline inspection.

Why a Snake-Like Robot?

A regular wheeled robot depends on a stable path and enough room for its wheels to move around a relatively even surface. In the case of a pipeline, which is a constrained environment, its diameter can limit the size of a regular-sized robot. Friction can also affect how the machine moves. That is one reason researchers have explored snake-like robots for in-pipe inspection. As opposed to a rigid wheeled platform, an articulated robot can distribute movement across multiple connected sections of its body. Further studies have also shown their ability to move through bends and maintain contact with the inner walls of pipes.

The most important part of the project was getting to reproduce the mechanics of the regular movement of a snake. When a snake moves forward, its body does not move as one rigid unit, but bends and straightens. One of the first challenges Aluko had to solve was how to make several servo motors work together to create something that actually resembled said movement.


In an update documenting his progress, he explained that getting realistic movement required wide research and relearning how sine waves work. His resulting approach was to use the sine function to determine the angle of each servo along the robot’s body. The servos would not all move to the same angle at the same time, instead, each one would receive a slightly shifted version of the same wave. As the wave progresses, one joint changes position, then the next, and so on. The result is a travelling bend that moves through the robot’s body.


RAIN’s project documentation describes this mathematically as phase-shifted sinusoidal control. The control system uses a sine-wave function to calculate joint angles, while the phase difference between the servos creates the travelling motion. If the servos simply moved together, the robot would bend and straighten without producing the same forward-propagating movement.

In Aluko’s early demonstration, the machine had not been completed. In his first project update, he showed part of the robot’s segmented body coupled together to show the motion. He described this as a breakthrough after struggling to work on how to reproduce the movement only using the servo motors. He also documented using Fusion 360 to develop his engineering designs, which was evidence that he was learning to think like a designer solving a physical problem. At one point, he paused work while waiting for the components he needed to proceed with the project to arrive.

Once the desired motion was achieved, he went further to document that the speed of the robot was too slow. This made him lean more towards its physical design. With fewer segments, the robot could generate only a limited body wave, meaning that less of its body was contributing to momentum over a period of time. He had to establish a relationship between the number of segments, movement of joints, friction and propulsion. In other words, the software and mechanical design could not be treated as separate problems.

In a post about the completed project, Aluko described it as one of the most technically challenging projects he had worked on and that it involved several failed attempts when the components did not work as they were expected to. But the final result was a machine capable of coordinated sinusoidal locomotion. This involved translating a mathematical model into commands, translating those commands into joint movements, and refining the physical structure when the resulting motion did not perform as it was intended to.


He eventually took the completed robot to the RAIN hackathon, where the project placed second overall and won first place in the People’s Choice Category.


The prototype does not yet represent a complete pipeline inspection system, as there is no evidence that it can currently detect corrosion or cracks, collect inspection data or operate independently inside an industrial pipeline. In its current state, it shows a segmented robot whose servo-driven joints can be coordinated through sinusoidal control to produce snake-like locomotion. 


For Aluko, the project involved working out how to produce biological movement mechanically, testing that movement in a physical system and changing the design when the first version did not perform well enough. This resulted in a working robotics prototype with potential application in one of the more difficult environments for conventional machines, which is the inside of a pipeline.



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