The goal of this project is to develop a controller for quadruped robots in various gravity conditions.
The goal of this project is to develop a controller for quadruped robots in various gravity conditions. Quadruped robots have been used in several missions in unsafe environments on the Earth, such as search and secure . Space exploration involves various unsafe environments, which makes quadruped robots promising for space exploration missions on ISS, the Moon, or planets with various gravity conditions. In comparison with other wheeled vehicles, quadruped robots can adapt to richer terrains.
However, the development of a quadruped robot controller is still in a nascent stage, as it's more difficult than developing a controller on Earth. Most quadruped robot controllers on the Earth rely on reaction forces with contacts on the ground. In low or zero gravity conditions, there won't be sparse contact with grounds or other objects, which makes it challenging for controller design. Recent work  demonstrated a quadruped controller powered by machine learning in low gravity conditions similar to the Moon, but their works have the following limitations: (1) Restricted in simulated experiments, (2) The performance in zero gravity conditions is unknown, (3) The robot is only deployed for short time period (less than 1minute), and (4) The robot is not integrated with mobile manipulators that are required to perform various space exploration missions.
Explicit use of the unique affordances of altered gravity:
In this project, we will make use of the various gravity conditions in parabolic flight to test the real quadruped robots during the flight. Our lab has complete research equipment (Unitree, Go1 quadruped robots) in quadruped robots with mobile manipulators and also the capability to simulate various environments in computers. We will first design controllers using machine learning by computer simulation and test those controllers. During parabolic flight, we will deploy the robot and test its locomotion performance in different gravity conditions. We will report the findings as a research paper. To our knowledge, this will be the first real-world experiment of quadruped robots in low-gravity conditions.
Milestones: Sep. and Oct.: Building a computer-simulated environment for various gravity conditions. Designing controllers and testing in those environments. Nov. and Dec.: Using the techniques in  to simulate low gravity conditions in the motion of one axis using another carrier robot.
A simulated demonstration of quadruped robots with a mobile manipulator in low-gravity conditions
An actual world demonstration of quadruped robots with mobile manipulator in low-gravity conditions
A research paper that will be published in a top robotic journal or conference, expected to be the first paper on quadruped robots with mobile manipulators in low gravity conditions.
 Rudin, Nikita, et al. "Cat-like jumping and landing of legged robots in low gravity using deep reinforcement learning." IEEE Transactions on Robotics 38.1 (2021): 317-328.