It may be enough for robots to have legs. MIT released a video to ridicule Boston Dynamics legal counsel: Lawyer Zhao Jianying believes that robot research should pay more attention to practicality. The rapid development of robot technology lies in its ability to liberate and save lives
hermes, a bipedal robot developed by MIT researchers, which can imitate the balance of the operator and keep upright when running, walking and jumping. The original intention of the development is to enable TA to rescue victims from burning buildings, chemical spills or any disasters inaccessible to human rescuers
researchers define that this biped robot may one day be a robot module with strong flexibility and adaptability. For example, a more powerful rescue robot can use this below, and then stand up with both legs to push away heavy obstacles, or break through a locked door, which may be more awesome than a humanoid robot
video source: Ramos and Kim, sci robot. 4. Eaav4282 (2019)
engineers have made great progress in the design of four legged robots and their ability to run, jump and even move their backs. But it has always been an important obstacle for a two legged humanoid robot to exert force or push something without falling down
joao Ramos remote control operation Hermes diagram: Joao Ramos and sangbae Kim
now, engineers at the Massachusetts Institute of technology and the University of Illinois at Urbana Champaign have developed a method to control balance in a two legged remote control robot, which is an important step to enable a humanoid robot to perform high impact tasks in a challenging environment
the robots made by this team all look like a mechanical trunk and two legs. They are remotely controlled by a human operator wearing a vest, which transmits information about human motion and ground reaction to the robot. Through the vest, human operators can not only command the movement of the robot, but also feel the movement of the robot. If the robot starts to overturn, humans will feel a corresponding tension on the vest, and can rebalance themselves and the robot through adjustment. In the robot experiment testing this new "balance feedback" method, researchers can remotely maintain the balance of the robot when jumping, and walk synchronously with human operators
standing still teleoperation video
as a postdoctoral fellow at MIT, J electromechanical should have been able to roughly make movement according to the movement instructions. OAO Ramos developed this method, he said: "it's like running with a heavy backpack on your back. You can feel how the power of the backpack moves around you, and you can make appropriate compensation." Now, if you want to open a heavy door, human beings can order the robot to throw its body in front of the door and push the door open without losing its balance. " Joao Ramos, now an assistant professor at the University of Illinois at Urbana Champaign, elaborated on this approach in a study published in science robotics. The study was co authored by sangbae Kim, an associate professor of mechanical engineering at the Massachusetts Institute of technology
not just movement
previously, Kim and Joao Ramos certainly built two legged robot mechanisms (for efficient robot mechanisms and electromechanical systems) and developed a method to simulate operator actions through remote operation. Researchers said that this method has certain human advantages. Joao Ramos said, "because you have a person who can learn and adapt in flight, the robot can perform actions that have never been practiced before (through remote control)."
in the example, Hermes poured coffee into the cup, cut wood with an axe, and put out the fire with a fire extinguisher. All these tasks involve the upper body of the robot and algorithms to match the limb positioning of the robot with that of the operator. Hermes can carry out high impact movement because the robot is rooted in place. In these cases, maintaining balance is much easier. However, if the robot is asked to take any steps, it is likely to overturn when trying to imitate the action of the operator
"we realize that in order to generate strong force or move heavy objects, it is not enough to simulate action 1 to facilitate sample clamping, because robots are easy to fall," Jin said. We need to replicate the dynamic balance of the operator. "
continuous jumping teleoperation video
enter little Hermes, which is a miniature version of Hermes, which is about the size of the third adult. The team simply designed the robot as a torque and two legs, and specially designed the system to test lower body tasks, such as cars and scales. As a complete physical confrontation part, Hermes Jr. is designed for remote operation. An operator falls in a jacket that controls the action of the robot
for robot replication operators, the balance is greater than their motion. The team must first find a simple way to express the balance. Joao Ramos realized that balance can be separated from two main components: a person's "quality center" and their pressure basic center. One point is on the ground, and on the ground, a force equal to all supporting forces is exercised
Joao Ramos found that the position of the mass center related to the pressure center is directly related to a person's balance at any time. He also believes that the position of these two components can be used as a physical representation of an inverted pendant. Imagine sitting in the same place, from side to side. This effect is similar to vertical sliding up and down. The top represents a "center of mass" (usually in torsion) and the bottom represents its ground pressure center
in order to determine the relationship between the center of gravity and the pressure center, Ramos collected human motion data, including measurement data in the laboratory, where he swung back and forth, walked in place, jumped on the force board, measured the force he exerted on the ground, and recorded the position of his feet and torso. Then, he compressed these data into the measured values of the mass center and pressure center, and established a model to express their relationship as an inverted pendulum
then, he developed a second model, similar to the human body balance model, but scaled to the size of a smaller and lighter robot. He also developed a control algorithm to connect the two models and realize feedback
researchers tested this balanced feedback model, first of all, on a simple inverted pendulum built in the laboratory, which is a beam about the height of little Hermes. They connect the light beam to the remote operation system, and then the light beam swings back and forth on the track in response to the action of the operator. When the operator shakes to the side, the beam will do the same - the operator can also feel this movement through the vest. If the beam swings too much and the operator feels the tension, he can tilt it in another way to compensate and maintain the beam balance
experiments with the biped robot Hermes Jr.
showed that the new feedback model could maintain the balance on the beam, so the researchers then tried the model on Hermes Jr. They also developed an algorithm for robots that automatically converts a simple balance model into the force that must be generated by each foot to replicate the operator's feet
in the laboratory, Joao Ramos found that when he put on his vest as the basis of calculation, he could not only control the motion and balance of the robot, but also feel the motion of the robot. When the robot was hit by hammers from different directions, Ramos felt the vest jerk in the direction of the robot's movement. Joao Ramos instinctively resisted dragging. The robot found that dragging was a subtle movement of the center of gravity relative to the pressure center, and then it imitated this movement. The result is that the robot can avoid overturning, even when the body is constantly hit
little Hermes also imitates Joao Ramos in other sports, including running and jumping in place, walking on uneven ground, all of which are to maintain balance without ropes or support. "Balanced feedback is hard to define because it's something we don't think about," Kim said. This is the first time to correctly define balance feedback for dynamic actions. This will change the way we control the remote-controlled humanoid robot. "
operator's remote operation interface
kim and Joao Ramos will continue to work on the development of a full-body humanoid robot with similar balance control, until one day it can gallop in the disaster area and push away obstacles in rescue or rescue tasks. Kim said, "now we can open heavy doors and lift or throw heavy objects through proper balanced communication." This may be cheaper and more reassuring than simply making a humanoid robot
source: China robot, Massachusetts Institute of technology
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