10-05-2012, 01:17 PM
The Revolutionary TETwalker
REVOLUTIONARY TETWALKER puppy.doc (Size: 586.5 KB / Downloads: 48)
ABSTRACT:
Like new and protective parents, engineers watched as the TETWalkerrobot successfully traveled across the floor at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Robots of this type will eventually be miniaturized and joined together to form “autonomous nanotechnology swarms” (ANTS) that alter their shape to flow over rocky terrain or to create useful structures like communications antennae and solar sails. NASA is testing a shape-shifting robot called “TETwalker” for tetrahedral walker, because it looks like a flexible pyramid. It has been tested in the lab and at the McMurdo station in Antarctica to test it under conditions more like those on Mars. Now, it is on the way to be really miniaturized by using micro- and nano electro-mechanical systems. When it’s done, in about thirty years, these nanotech swarms will “alter their shape to flow over rocky terrain or to create useful structures like communications antennae and solar sails.” So in 2034, nanotechnology will land on Mars.
INTRODUCTION TO TETWALKER:
NASA Goddard Space Flight Center offers the opportunity to partner in the further development of this innovative technology for use in robotics and other applications requiring extreme mobility and adaptability in varied environments.
The TETwalker represents a revolutionary idea in robotics and structural architec¬ture. It is a creative application of Addressable Reconfigurable Technology (ART), developed by NASA researchers at Goddard Space Flight Center working jointly with Langley Research Center. This highly integrated three-dimensional mesh of actuators and structural elements has the potential to autonomously change form to optimize its function, reconfigure into specific tools, and perform tasks in a wide range of terrain and environment. This is the first element in the development of a synthetic skeletal muscular and skin system, to be controlled by a synthetic neural system.
Disadvantage of previous robots in space:
They
Do not work in Extreme Thermal Conditions. Require High Reliability Requirements.The very low-pressure in orbit causes metal parts to cold-weld together, atomic oxygen to react with almost any material and nullifies the cooling benefits of convection for electronics.
Radiation also differs from that encountered on Earth and in space, heavy particles make digital electronics misbehave or even burn. Thermal conditions are also extreme, with external temperatures ranging from plus or minus more than a hundred degrees centigrade.
Another characteristic of space missions is that robots have to operate far away from their home base. Radio signals to control and monitor them have to travel for a long time and this introduces communications delays prohibiting real-time or near-real-time tele-operation. Therefore space robots must be able to operate on their own and handle any problems that occur while carrying out their tasks.
hence we go for autonomous system i.e., TETWALKER.
PURPOSE OF TETWALKER : The purpose of the tetrahedral walker (Tetwalker) project is to extend current space exploration into regions currently inaccessible by traditional wheeled or humanoid robots.
CHARACTERISTICS:
• Lightweight and compactness.
• The structural material used has high specific strength and high specific stiffness, to ensure compactness, minimum mass and high stiffness.
• Will subject to the dynamic loads during launch.
• These dynamic loads are composed of sinusoidal vibrations, random vibrations, acoustic noise and separation shock spectra.
• The components are protected against radiation to ensure proper performance throughout its life in orbit.
• Possess a very high degree of reliability and this is achieved right from the design phase of the system.
• A failure mode effect and critical analysis (FMECA) is carried out to identify the different failure modes effects and these are addressed in the design by choosing proven/reliable designs.
THE TECHNOLOGY:
The tetrahedron module is configured using readily available, addressable, elec¬tro-mechanical components. Lightweight telescoping struts are attached at each end to pivoting nodes to allow movement over a wide range of angles. Motors within the nodes control the telescoping struts, allowing specific sections of the tetrahedron to lengthen or shorten, changing its center of mass. This enables the tetrahedron to maneuver in a controlled flip-flop motion by toppling over in alternating directions.
By grouping multiple tetrahedra, many degrees of freedom/function and much smoother locomotion are possible, including the formation of flattened and conformable surfaces (e.g., draping over obstacles) as well as slithering, rolling, and amoeboid/caterpillar-like motions. Independent shaping of the top and bottom interconnected nodes is also possible, to allow reconfiguration for multiple complex functions, such as forming tools and for communications.
While the TETwalker is currently controlled remotely, also under development is a synthetic neural system to enable the TETwalker to function autonomously. This neural system will allow the TETwalker to adapt and actively reconfigure itself according to its environment and recognized needs. Like the physical architec¬ture, the neural system has a three dimensional node-driven architecture.