Energy efficiency: Four-legged robots should move like turtles
Robots with legs should be able to walk as efficiently as possible and consume as little energy as possible. Turtles are a good example of this.
(Image: DGIST)
A research team from the Department of Robotics and Mechatronics at the Daegu Gyeongbuk Institute of Science & Technology (DGIST) in South Korea has discovered that turtles are particularly energy-efficient in relation to their heavy weight, making them a suitable model for energy-efficient robots.
Legged robots are not particularly energy-efficient compared to wheeled robots, but they do make better progress on rough terrain. The South Korean research team has therefore given some thought to what a four-legged robot that can move around in a particularly energy-efficient manner should look like. In the scientific paper "A Study on the Effect of Belly-Dragging Locomotion on a Robot that Mimics a Heavy Reptile", published in Advanced Intelligent Systems, the researchers describe how turtles have developed the most effective method of locomotion.
They observed the reptiles and identified two fundamental factors for the energy efficiency of their movement in relation to their high body weight: they drag their shell across the ground and at the same time move their diagonally arranged legs. Through simulations, the scientists found that this type of locomotion requires less energy than other forms of locomotion. Even when the researchers changed variables such as the size and mass of the turtle robot, locomotion remained energy-efficient.
More efficient with a sliding shell
The scientists verified their observations and simulations with a physical turtle robot with four legs and a shell, which they produced using a 3D printing process. The researchers moved the legs using a total of twelve servomotors, which they controlled using an OpenCM 485 controller board. This enabled them to make the four-legged robot, which weighs around 1.8 kg, move in different ways. They compared the method used by turtles to slide over the ground with their belly plate (plastron) with a method with a raised shell and a raised method without a plastron. The researchers also varied the leg movement. As a result, the scientists determined that the turtle's locomotion is most efficient when using the ventral plate.
The research team therefore advises that robots that need to move in a particularly energy-efficient manner should be designed based on the research results they have obtained.
(olb)