At the end of May last year we posted up a video of a quadrotor helicopter capable of aggressive movement. The movement was so accurate that the quadrotor could fly through a window at speed with less than 3-inches of clearance and at multiple angles. It could also do multiple flips while retaining full movement control, and land on angled surfaces (even upside down) using a Velcro pad as an anchor.
The project was headed up by David Mellinger at the University of Pennsylvania’s GRASP Lab. Since then work has continued with the quadrotors to make them more useful. The latest development is teams of quadrotors working together to build structures with a new gripper attached to their underside.
The quadrotors have been programmed to pick up and use parts of a framework to build a tower structure. Each end of the frame sections has a strong magnet allowing it to stay in place if positioned correctly next to other frame sections. The quadrotors just have to accurately place the framework in either a horizontal or vertical position.
Once positioned they check a piece is secure with a “yawing moment” which attempts to twist the section. If it remains in place then the quadrotor determines it is positioned correctly and moves on. If it moves out of place it obviously isn’t secure and the quadrotor tries to position it again.
The accuracy the quadrotors have in picking up and placing the frame sections is impressive enough, but they can also work as a team. Each quadrotor can keep track of the others that form part of the team working on a given structure and navigate around them. This drastically speeds up the construction of a tower.
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The important technology on display here is the accuracy of the quadrotors and the ability for them to work together. In their current small form the potential for them carrying objects is limited, but there’s nothing to say the quadrotors couldn’t be scaled up and made to carry much larger cargo.
The one limiting factor of the quadrotors is their battery life. But with such accurate movement it shouldn’t be difficult for them to navigate to and land on a charging pad. With teams of quadrotors working together recharges could be handled in such a way that there is always an active group of quadrotors working.