Modular robot design uses tether jumps for planetary exploration

Recent technological advances have opened up new possibilities for the development of robotic systems, including spacecrafts for the search of other planets. These new systems may ultimately contribute to our understanding of galaxies and the unique properties of many celestial objects that they contain.

The Romera researchers, the Institute for Robotics and Mechanisms at the University of California, Los Angeles (UCLA), designed a splitter, an intelligent tethered technology exploration robot for space and planets. By the tether.

Their proposed system, which is scheduled to be announced at the IEEE Aerospace Conference (Aeroconf) 2025, can also jump to the surface of the moon or asteroid and collect data from its surroundings. This work is also available on the ARXIV preprint server.

“The inspiration for this study comes from the challenges of motion and attitude control in low-gravity environments such as the moon and asteroids (3D directional control),” Tanaka, the first author of The Paper, told Tech Xplore I did.

“Traditional rovers are large, heavy and slow, limiting the area and efficiency of planetary exploration.

“Airborne solutions like drones can observe larger surface areas than rovers, but are unrealistic because there is no atmosphere on the moon or asteroid.”

The Romela research team previously introduced the Limbed Climbing Robot. This was called the Scaler (automatic leg exploration robot that strengthens the spine) designed for planetary exploration.

However, when they tested this robot, they discovered it was moving slowly, both on walking and climbing. Therefore, they set out to explore ways to increase its efficiency without dramatically changing the overall structure.

“The main purpose of this paper was to demonstrate attitude control through inertia morphing by adjusting the inertia associated with changes in limb composition and tether length.

“Our one is one of the first (if not the first) approaches to achieving attitude control through inertia morphing using a Model Prediction Controller (MPC).”

In their new study, Tanaka and his colleagues introduced an MPC-based inertia morphing mechanism. This mechanism adjusts the orientation of the robot during flight and improves stability.

“The inertia morphing mechanism utilizes the tennis racket theorem (dzhanibekov effect), which explains how objects with asymmetric inertia experience spontaneous flips when rotating about an intermediate axis.” Tanaka explained.

“Our inertia morphing-based attitude controllers use this principle to enable us to actively stabilize the stability of air flights in a controlled way.”

The researcher’s paper outlines the design of a new robotic system called a splitter, including the actuator specifications required for its operation. The robot is essentially composed of two small, four-legged robots called hemisplitters, connected by tethers to form a dumbbell-like structure.

“The robot’s limbs are strong enough to jump under reduced gravity, but require stable mid-flight control,” Tanaka said. “Instead of relying on heavy reaction wheels and gas thrusts for attitude control, the splitter dynamically changes its inertia by adjusting the length of the tether and the position of its limbs.”

The new system designed by this research team could have many advantages over many previously proposed robots for planetary exploration. One of its important benefits is its mass efficiency. This eliminates the need for dedicated attitude control hardware, such as gas thrusters, reaction wheels, wings and improved agility.

“Tether mechanisms can also help explore planets,” Tanaka said. “For example, one hemisplitter can enter a crater or cave, while the other side is fixed to support. Successful jump movements are effective because they can store jump energy in rotation. That is, You can continue to accelerate with each jump.”

The design of splitter robots and the mechanisms that support their movements may be particularly suitable for exploring low-gravity environments. In these environments, traditional wheeled robots have been found to be inefficient, but aerial robots are not always easy to deploy.

“Our findings show that splitters can control the posture of airborne robots through inertia morphing techniques using MPC in simulations,” Tanaka said. “We have shown that using MPCs the system can adjust angular velocity/direction to maintain stability without the need for external forces or momentum wheels.”

Researchers envision the deployment of robotic systems as a swarm of robots, which allows efficient crossing and exploring the vast, unstructured environment. The MPC-based inertial morphology mechanisms they developed could potentially be applied not only to satellites and spacecraft, but also to other robots to improve the stability of space.

“Our future research will focus on splitter experiments in high fidelity simulations to further validate inertia morphing MPCs, which allow for more accurate physics simulations and robotic motion analysis,” Tanaka said. added. “This paper is part of Project Splitter, the fundamental task of studying the technology needed to develop splitter hardware.”

Currently, the Romela team at UCLA is working to further strengthen the robot’s hardware. For example, they focus on developing new actuators and splitter sensing mechanisms, allowing them to broaden their capabilities.

“Our lab expertise lies mainly in Legiod’s robots, for ground movement on Earth. We have learned from decades of research developing these systems. is applying them to space applications.

Dr. Dennis Hong, the project’s PI and director of Romela, told Tech Xplore, “With new challenges, we will create new solutions and new knowledge that will make this work more meaningful and interesting.”

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