Nabi and Alphred are two of the latest examples, in the fields of bipedal and humanoid robots developed by RoMeLa, the Robotics and Mechanisms Laboratory at UCLA. This is a transcript of the TC Sessions Robotics 2018 demonstration given by by Dennis Hall, professor and director of the RoMeLa Institute.
UCLA RoMeLa is specialised in research and development of robotics and is one of the early pioneers and autonomous vehicles in this field. In 2007 at DARPA urban challenge it placed third place. They come up with all different types of mechanisms from three-, four- and six-legged robots to chemically actuated and wheel-legged hybrids. However, in the past 10 years decade developers at the institute have been focusing more on humanoid robots, like the open-source robot Darn Opie, funded by the National Science Foundation and Charlie, the fully autonomous soccer-playing robot that uses series of linear actuators. Another example is Sapphire, the ship or autonomous firefighting robot funded by the navy for fighting fires on Navy ships.
Humanoid robots are great in science fiction, but they are unstable, constantly fall down and are too slow. Furthermore, they are too expensive and too complex, but we do need them. So, what do we do? Why is it difficult to implement bipedal locomotion on robotics? It is because of the distance between the left and right leg. A leg moves up and down and forward and backward and because of distance creates an unwanted, twisting moment which is the reason why robots fall down.
However, during the RoboOne Competition, a popular robotics competition among hobbyists, we can see stable and very fast robots. They don’t fall down. How? Because they walk sideways, so the left and right leg are aligned, and so they don’t get the twisting moment and therefore are stable. Professor Hall got the inspiration from fencing or ballet dancers who move sideways.
NABi stands for Non-Antropomorphic Biped and is a bipedal robot prototype configurated for simplicity, speed and stability. It walks simple, stable and low-cost. It can step over high door seals by rotating the knee 360 degrees and even can climb stairs. It can hop and jump using the spring-like leg. The goal is to use this robot for many different applications. For example, picking up packages from autonomous delivery cars. So it will need two extra limps for the lifting which can be used in other environments as well, e.g. opening doors. NABi becomes more humanoid.
Therefore, a new robot has been developed called ALPHRED, an Autonomous, Legged, Personal, Helper Robot with Enhanced Dynamics. Its four limbs can be used for both locomotion and manipulation, called multimodal locomotion. It can have a wide sprawl quadruped walking, stable and slow. If it wants to go really fast, it changes its configuration to enable a dog- or horse-like gait. The vision is to have it built with a wheel to perform a somersault kind of motion.
Most robots today use high-geared electric motors as actuators. These are stiff and positioned controlled, not back-drivebale. These are good for accurate motions in assembly tasks, for instance. But for walking on uneven terrains, you need to have an actuator like a muscle that is compliant and can change the position, the stiffness and the force. So therefore, a new actuator, called BEAR has been developed. BEAR stands for Back-drivable, Electromagnetic Actuator for Robots.
This actuator is a revolutionary new technology with all physical properties to control stamping and spring movements and accurate motions at different damping, stiffness and speed levels.
NABi/ALPHRED version-2 is a combination of the first models of NABi and ALPHRED with the new BEAR actuator implemented. It can be used as a conventional stiff robot, but it can also be set to be compliant and perform roll, jumps and other crazy stuff. At RoMeLa, they believe that it will be a break-through.