Robotic vehicles that are capable of autonomously transitioning between various terrains and fluids have received notable attention in the past decade due to their potential to navigate previously unexplored and/or unpredictable environments. Specifically, aerial-aquatic mobility will enable robots to operate in cluttered aquatic environments and carry out a variety of sensing tasks. One of the principal challenges in the development of such vehicles is that the transition from water to flight is a power-intensive process. At a small scale, this is made more difficult by the limitations of electromechanical actuation and the unfavorable scaling of the physics involved. This paper investigates the use of solid reactants as a combustion gas source for consecutive aquatic jump-gliding sequences. We present an untethered robot that is capable of multiple launches from the water surface and of transitioning from jetting to a glide. The power required for aquatic jump-gliding is obtained by reacting calcium carbide powder with the available environmental water to produce combustible acetylene gas, allowing the robot to rapidly reach flight speed from water. The 160-gram robot could achieve a flight distance of 26 meters using 0.2 gram of calcium carbide. Here, the combustion process, jetting phase, and glide were modeled numerically and compared with experimental results. Combustion pressure and inertial measurements were collected on board during flight, and the vehicle trajectory and speed were analyzed using external tracking data. The proposed propulsion approach offers a promising solution for future high-power density aerial-aquatic propulsion in robotics.

https://robotics.sciencemag.org/content/robotics/4/34/eaax7330.full-text.pdf

Consecutive aquatic jump-gliding with water-reactive fuel

A novel water jet thruster which is capable of conducting two sequential jumps is proposed for the amphibious jumping robot. The proposed water jet thruster adopted a unique structural design with ...

Study of a new water jet thruster for robotic returnable jumping

A squid-inspired swimming robot using folding of origami

In this study, we demonstrated a novel jumping robot that has the ability of accurate obstacle-crossing jumping and aerial pitch control. The novel robot can quickly leap high into the air with a powerful water jet thruster. The robot was designed to overcome multiple general obstacles via accurate jumping. Then a modified whale optimization algorithm (MWOA) was proposed to determine an optimized jumping trajectory according to the form of obstacles. By comparing with classical intelligent optimization algorithms, the MWOA revealed superiority in convergence rate and precision. Besides, the dynamics model of aerial pitch control was built and its effect was verified by the pitch control experiment. Lastly, the robot’s obstacle-crossing experiments were performed and the results validated the robot’s good ability of obstacle-crossing and aerial body righting. We believe the optimization of trajectory and the pitch control are of great help for the jumping robot’s complex jumping and obstacle-crossing performance.

Study of Obstacle-Crossing and Pitch Control Characteristic of a Novel Jumping Robot.

A soft quadruped robot that can perform linear locomotion and turning patterns is proposed. The silicone rubber legs were cable-actuated and powered by motors. First, the bending behavior of the soft legs under quasi-static conditions was studied, and then mathematical models for linear and turning motions were established based on gait analysis. The soft-legged robot can decouple linear and turning motions. Furthermore, slope walking and payload were experimentally tested. The results showed that the robot can conduct linear locomotion at a speed of 19.8 mm/s and turn with an angular velocity of 4.4°/s. In addition, it had a payload of up to 300 g, and performed well on a smooth surface with a 17° slope. 

Walking locomotion of a cable-driven soft-legged robot

In nature, certain aquatic animals and seabirds are capable of leaping from water surface and overcoming aquatic obstacles with ease. Inspired by that, researchers have developed various underwater...

Design, analysis, and performance verification of a water jet thruster for amphibious jumping robot:

Compared to other types of mobile robots, amphibious jumping robots have good ability of overcoming obstacle and can adapt to various environments. This paper mainly introduces the Study of a miniature amphibious gas-powered liquid jet thruster which can be used on amphibious jumping robots. We lists three kinds of jet thruster structures in this paper, which are the spring-driven valve type structure, the magnetic clamshell valve type structure and the hot melting glue valve type structure. Then we compare the advantages and disadvantages of each structure. After that, through theoretical modeling analysis and simulation analysis, the performance of the jet thruster is calculated. In the part of experiment, a jet thruster with a hot glue valve type structure, which weight is approximately 550g, is manufactured. The experimental propulsion performance of this experimental device is verified by terrestrial jumping experiment and aquatic jumping experiment. Among them, in the aquatic jumping experiment, the jet thruster reached a maximum height of about 15m, and in an aquatic jumping experiment, the jet thrust reached a maximum height of about 9.5m. This study designed a feasible jumping propulsion device for the amphibious jumping robots, and also provided a research method combining theoretical modeling and simulation calculations for the theoretical research of gas-power liquid jet thruster.

Yunlu Zhang

Papers

Design, analysis, and performance verification of a water jet thruster for amphibious jumping robot:

Study of a Gas-powered Liquid Jet Thruster for Amphibious Jumping Robot *