Landmines are inexpensive weapons of war, yet they overwhelmingly harm civilians. Almost 85% of landmine victims in recent years have been non-combatants, with more than a third of those injured or killed being children, according to the Landmine Monitor and Human Rights Watch. One promising approach to detecting and neutralizing landmines involves multi-legged robots that integrate soft and rigid components, which are designed to cover a wide variety of terrains.

That’s where Markus Nemitz, an assistant professor of mechanical engineering, comes in. He was recently awarded a four-year, $1.7 million grant from the Office of Naval Research to develop the next-generation crab-inspired robots for aerial deployment and amphibious operations, building on his group’s earlier advances in 3D printed, multi-material, multi-legged robots.

“In this project, all of the robots we develop are inspired by crabs,” said Nemitz. “We want these four, six, or eight-legged robots to navigate highly complex environments. They need to walk on sand, climb over rocks and obstacles, and even traverse terrain underwater. Crabs are remarkable at doing all of that.” 

To refine the mechanics, Nemitz and his group are working with Markus Frederich, a professor and marine scientist at the University of New England who studies energy metabolism and stress physiology in marine vertebrates. His experiments include observing the movements of crabs on miniature underwater treadmills.

Nemitz will model robot locomotion on crab movement, and apply machine learning to help the robots adapt to large variations in terrain. “The way these robots will interact with their environment will be similar to how a child learns,” he said. “We first learn to walk through trial and error, adjusting until we succeed. In the same way, the robots will be trained with reinforcement learning to walk across different terrains.”

Another key aspect of the project is automating robot fabrication through a combined strategy: electronic components are picked and placed by robotic arms, while chassis and limbs are 3D-printed from multiple materials. This approach enables full integration without human intervention, ensuring manufacturing remains economical and scalable.

Landmines are cheap to deploy, but expensive to detect and remove. “If we can field swarms of small robots that are less expensive to produce than the mines themselves, we may begin to reverse this tragic imbalance,” said Nemitz.

The crab-like robots Nemitz is developing could be deployed in great numbers for a wide range of civilian applications, he said. In addition to explosive ordnance disposal, they could be used to monitor oceans, detect glacier melting and movement, track animal populations, and assist in search and rescue operations. 

The new grant also highlights the vital role of undergraduate students in the research. “Undergraduates contribute significantly to this work,” said Nemitz. “More than 20 undergraduates have already been co-authors on our published studies, and I encourage anyone interested in the emerging field of applied swarm robotics to reach out to me.”