Robots Climb to New Heights

Climbing robots have garnered significant attention in recent years due to their potential to perform tasks in challenging environments. These robots are designed to navigate surfaces such as walls and ceilings, making them useful for a wide range of applications like search and rescue, building maintenance, and military operations.

One major advantage of these robots is their ability to access areas that may be difficult or impossible for humans to reach. For example, climbing robots could be used to inspect the exterior of a high-rise building or to search for survivors in the aftermath of a natural disaster. Another benefit of climbing robots is their potential to perform tasks more efficiently and safely than humans. For example, a climbing robot could be used to paint a building or perform routine maintenance tasks without the need for scaffolding or other safety equipment.

Of the many types of climbing robots that have been developed, from those with adhesive feet that mimic those of a gecko, to those with wheels that run on tracks, magnetic climbing robots have proven to be among the most reliable (as long as the climbing surface is made of a ferromagnetic material, that is). However, that reliability has come at the expense of low movement speeds and being limited to only very simple locomotion tasks.

Recent innovations by a team of researchers split between the Korea Advanced Institute of Science and Technology and the University of Illinois at Urbana-Champaign have made great strides in addressing the present shortcomings of magnetic climbing robots. Their untethered quadrupedal climbing platform, called MARVEL (Magnetically Adhesive Robot for Versatile and Expeditious Locomotion), is capable of rapidly traveling along ferromagnetic walls and ceilings. Importantly, it can make successful transitions between planes (e.g. between the floor and a wall), and it can also traverse gaps and obstacles. This set of skills may make MARVEL an attractive platform for real-world applications.

To make MARVEL possible, the researchers designed a new type of feet for their quadruped robot. They leveraged electropermanent magnets, which have a very fast switching time and are very energy efficient to provide the holding power. These magnets were used in conjunction with magnetorheological elastomer footpads that increase the holding pressure and give the robot added agility.

To control the movement of these legs, a proprioceptive actuation scheme was implemented. This allows MARVEL to move in a way that is similar to humans or animals, as this control mechanism allows the robot to adapt to changing environments and respond to external stimuli in a more natural and intuitive way. This technique also prevents slipping and tipping over during foot adhesion to surfaces.

A series of experiments were conducted to assess how well the robot would perform under real-world conditions. It was found that MARVEL could move along ceilings and vertical walls at a very speedy pace of 1.51 and 2.12 body lengths per second, respectively. The robot was also demonstrated as being capable of stepping over gaps of up to 10 centimeters and climbing past obstacles up to 5 centimeters high. When it came time to transition between floors, walls, and ceilings, MARVEL was found to be up to the task, making the shift without difficulty.

In the future, the team envisions their technology being used at industrial sites, including steel-structured buildings, bridges, ships, or storage tanks to perform inspections or maintenance. Working towards that goal, the team is currently investigating ways to give MARVEL enhanced adhesion on very irregular or sharply curved surfaces.