Birds are known to literally have a handle to land safely on branches and the like. Similar to the leg-claw system, researchers have now developed a robotics concept that enables drones to perch on branches or grab objects. In the future, ‘SNAG’ could enable aircraft to take energy-efficient breaks when exploring the natural environment.
Thick, thin, convex, slippery…: The branches can have many different characteristics however birds can land on most copies without any problems. Obviously, the function of their claws and legs along with their sense of balance can ensure this adaptability. This is an interesting nature concept also from an artistic point of view. Because until now, the possibilities of landing aircraft on targets with uneven surfaces were limited. For example, methods for catching and settling birds have come into focus for researchers working with William Rodrik of Stanford University.
Investigations into the landing behavior of young parrots formed the basis of its technical implementation of Nature’s Patent. Scientists recorded the animals using high-speed cameras as they flew back and forth between special perches. The targets were of different sizes and consisted of different materials such as wood, foam, sandpaper or Teflon. The roosts also contain sensors that record the physical forces that occurred when the baby parrots land, sit, and take off.
Natural Model Analysis
“The amazing thing is that the animals did the same maneuvers no matter what surface they landed on,” Rodrik says. “They left it up to the feet, so to speak, to respond reasonably to the diversity and complexity of the surface structure.” The researchers explain that this is not a question of “intentional” behavior, but rather an unexpected phenotypic mechanism that underlies the birds’ flexible landing capabilities. They then used this principle and other aspects as a basis for developing their concept of the artistic application of the animal system.
This is how the Modular Nature Inspired Air Pistol (SNAG) came to be — a technical leg and claw system that can be attached to a quad drone. In order to take into account the size of the quadrocopter, SNAG elements are designed on the leg and claw structures of the hawks. The bones are imitated by 3D-printed plastic elements and the function of muscles and tendons is performed by actuators and fishing lines. Each leg in the concept has a thrust element to move back and forth and another to enable grip.
Also inspired by structures and processes used in birds, the robot’s system mechanism absorbs shock energy during landing and passively converts it into a gripping force. The result is that SNAG has a particularly strong and fast coupling that can be turned on and off within 20 milliseconds, the developers explained. As soon as the mechanism has a branch under control, the integrated accelerometer reports the landing on the system and activates the stabilization function: a special compensation algorithm ensures that the drone is in a stable position.
Promising test results
The researchers have already demonstrated the performance of the system through practical tests. In this way, they were able to demonstrate that a drone equipped with SNAG can safely land on objects of different design. In addition, small items can be grabbed and carried away. Experiments have documented that techno’s tentacles react so quickly upon contact that they can grab a lying object such as a bag full of beans or a tennis ball.
The performance of SNAP under natural conditions was also shown: the scientists reported that tests of landing on branches in the forest led to promising results. To further develop the concept, they now want to focus on improving preparation for landing in complex environments. This requires, for example, improving the capabilities of the position detection and flight control of the robot system.
When the landing system is fully developed, it could have a number of uses, say Rodrik and colleagues. The potential lies above all in the breaks. Because the high demand for energy and the lack of landing opportunities have so far severely restricted the use of drones. One potential area of application for this system is search and rescue or forest fire monitoring. However, the researchers particularly emphasize the potential uses of SNAG in environmental research: “Part of the motivation for this work has been to develop tools that we can use to explore the natural world,” says Rodrik. “If we had a robot that could act like a bird, it could open up entirely new ways to search for the environment,” says the scientist.
Source: Stanford University, technical article: Science Robotics, doi: 10.1126/scirobotics.abj7562
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