Legged robots are slowly swarming many industries today. With the help of robotic innovations like the legged machines, people can perform real-world tasks that need extreme solutions, such as guarding a place non-stop overnight and having the right speed and load limit for many logistic purposes.

Today, experts are trying to work on small-sized robots that can maneuver around tiny areas not reachable by humans.

Meet SQuRo: Small Quadruped Robot Based on Rats

Small Quadruped Robot “SQuRo” Developed to Mimic Agility of Rats, Can Carry Objects as Heavy as Its Own Weight
(Photo: IEEE Transactions on Robotics / Beijing Institute of Technology)
SQuRo

Previous studies have shown how machines based on quadruped animals, like ANYmal and BigDog, can perform in terms of load capacity and adaptability to the immediate environment. However, these standard-sized robots can not enter narrow spaces perfectly.

These robotics, categorized as sub-2g machines, might have to perform the extra effort in order to slip in through spaces unreachable by humans but do not perform tasks requiring their load capacity due to the limited cargo they have.

With that said, experts developed a new machine that could cater to all the requirements needed to adapt to smaller environments while also being able to carry light payloads in and out of the spaces.

Brown rats, also known as Rattus norvegicus, are small animals that contain the agility and physiology that is perfect for small-scale jobs. The way they move and adapt throughout any given environment fascinated many engineers, and this allowed the experts to have the best inspiration for robots that can match what larger machines lack.

Scholars from China's Beijing Institute of Technology, led by professor Qing Shi, initiated research to mimic the unparalleled natural movements of the rats. The main purpose of the study is to embed the animal's skills into a machine in an attempt to create a small-sized, quadruped robotic system.

The rat robot, named SQuRo, was a product of more than a decade of robotic studies carried out by Shi's team. Previous research conducted by the experts produced several innovations that were based on natural skills that selected animals have, EurekAlert reports.

This new bioengineering advancement takes the robotic animals to a whole new level, as SQuRo behaves, moves, and does other tricks that mirror what an actual brown rat does. In the research, the team equipped the rat robot with specialized legs instead of the conventional wheels that many robots were equipped with.

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How SQuRo Works

Biological rats move and adapt to smaller spaces by utilizing their stretchable, elongated slim bodies. For SQuRo to copy the animal's agility, the scientists programmed the closest motion patterns of the rats to the machine.

In addition, they customized the morphology of SQuRo according to the exact key movement joints (KMJ) of the animals in order for the robot to perform as close as the rats when moving in and out of enclosed, tiny areas.

The algorithm programmed into SQuRo is based on the degree of freedom (DOF) configuration. With this approach, each limb, as well as the waist part of the rat robot, can replicate the flexibility of the tiny animals and even respond quickly such as turning around without any delays.

SQuRo can also fall from a certain height but can recover fast. It can even perform multimodal motions such as walking, turning, crouching, and standing right after an unexpected drop with the help of its own adjustments on its center of mass (CoM).

SQuRo can pass obstacles as small as 30 millimeters in height, and enter irregular, narrow paths as tight as 90 millimeters. It can turn inadvertently at a radius of 0.48 body length and can travel in terrains angled as much as 15 degrees. The rat robot can also carry payloads that measure 91 percent of its own weight.

The study was published in the journal IEEE Transactions on Robotics, titled "Development of a Small-Sized Quadruped Robotic Rat Capable of Multimodal Motions."

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