Motors are machines used to convert electrical energy into mechanical energy. Linear actuators are special kinds of motors used in a robot to convert the stored energy into movement. Robotics is an area that has helped in the exploration of space. This article looks into an ongoing research of shape-shifting robots.
A group of engineers came up to design the next generation of robots that explore space. This includes Alice Agogino and her lab, who is a mechanical engineering professor at the University of California, Berkeley. The point is to design smaller robots, which are different with the Mars rovers that had the big wheels. The models of these robots are inspired by a baby toy and look like a ball made of cables and balls.
This all began in a brainstorm of how to improve space robotics, between Vytas Sunspiral, who is a robotics researcher and his colleague who is Alice Agogino’s son, Adrian Agogino. Adrian is a robotics researcher too. During the brainstorm, they happened to be having a baby toy, a Skwish. The structure of the Skwish is known as a tensegrity structure. In these kinds of structures, rigid parts like steel beams and wooden rods are connected using wires, chains, cables or any other kind of band. This is preferred instead of being held together using screws or nails. No matter how hard you throw or squash them, they do not break. Thus, they become the most fun baby toys to play with. After they impact, the tensegrity can easily absorb and distribute resulting forces. After throwing around this toy and making observations on its ability to remain in one piece, Sunspiral’s team came up with the idea that this kind of structure would aid space robots’ landing structure immensely.
Traditional space roots, the Mars rover, for example, have a difficult landing problem. This is because of their nature: they are pretty delicate and usually are approaching the planet at very high speeds. A lot of money and time is spent to make sure that everything stays intact during landing by the engineers. Landing Curiosity, which is the current robot on Mars, has been given a nickname, 7 minutes of terror. Furthermore, traditional space robots are limited to the places that they can explore.
Robots made of tensegrity materials are cheaper to make and might be easier to land. The could even solve the exploration challenge of bad terrains altogether. Alice Agogino explains that among the advantages offered by tensegrity Rovers over wheeled ones are being lighter in weight, are more robust and can handle loads of damage since the load is distributed along all the tensile elements.
NASA gave Sunspiral and his colleagues an Innovative Advanced Concept award to test if they can make the structures move and perform tasks required for space exploration.
A lot is involved in designing one of these robots. At a glance, computers control the motors. This motors in turn cause the cables to compress or stretch. The structure thus changes its shape, alters its center of gravity and creates a rolling motion. Eventually, these robots could carry instruments like sensors and cameras.
Several prototypes of the tensegrity structures have been created in Agogino’s Lab, Berkeley. Each prototype is made up of different parameters from the next one, for example, the location of the motors, the materials used and the type of motors. After making the prototypes, tests are carried out. They include how much energy they require moving, how fast they go, how the respond to different environments, how far they can be dropped and how much weight they can carry. The also explore how to best program the robots using NASA’s Tensegrity Robotics Toolkit (NTRT).