Scientists from Skoltech have presented the concept of a modular Mars rover. It is based on the principle of cooperative robotics: the vehicle is divided into four two-wheeled robots, which can function independently or dock in different combinations. The scientific team shows that the modular design will multiply the time of active work on Mars, and therefore the amount of information collected on the history of the planet, its habitability and the presence of traces of life and water.
The work is published in an article in the journal Acta Astronautica. "A group of robots, the Ingenuity helicopter and the Perseverance rover, are already in use by NASA on Mars. This arrangement makes it possible to leverage the advantages of each agent in a heterogeneous system. For example, an unmanned helicopter, with its high speed and ability to view space from altitude, makes it possible to plan the movement of a slow-moving mobile robot," says Dmitry Teteryukov, associate professor at Skoltech and head of the Intelligent Space Robotics Laboratory.
However, since the first mobile exploration vehicle - the NASA-launched Sojourner - successfully landed on Mars in 1997, the basic design of planetoids has not changed much: in particular, all scientific equipment moves on a six-wheeled mobile robot. But scientists working in the field of group robotics suggest that more results could be achieved during a single mission to Mars by sending several smaller robots to the Red Planet, which are equipped with different equipment and can both disperse in different directions and dock to perform more complex tasks.
"A swarm of two-wheeled robots is capable of joining forces to explore the surface or move massive objects, for example. Instead of sending a heavy and energy-consuming rover, an exploration mission can be accomplished using a unique set of two-wheeled robots, each carrying a different instrument - such as GPR, or spectrometer, or sample collection equipment. And by forming a linked chain, the robots would be able to transport heavy or large objects," says Teteryukov.
Aleksandr Petrovsky, the first author of the article, a PhD student at Skoltech, specifies: "Essentially, we solved the problem of optimization: how to achieve the longest operating time and cover the maximum distance without blowing the budget to bits. It turned out that a six-wheeled glider is not the best solution. According to our calculations, the optimal solution is four two-wheeled vehicles. Each has different instruments on board and only the critical payload is duplicated in all four modules."
The solution assumes that even if three robots fail, the last, fourth robot will be able to continue carrying out some research tasks alone, transmit information back to Earth and more progress will have been made by the time the mission is complete. At the same time, some activities - such as grabbing soil samples - require increased stability. For this, the two robots can dock to each other.
"Generally speaking, the risk of flipping is a major drawback, and for the rest of the parameters we examined, a grouping of four robots looks advantageous, or at least not particularly inferior to a standard Mars rover," adds Petrovsky. - And even in this sense, two-wheeled robots have made quite a 'step forward', so instability is no longer as big a problem as it used to be."