Applications of mobile ground robots demand high speed and agility while navigating in complex indoor environments. These present an ongoing challenge in mobile robotics. A system with these specifications would be of great use for a wide range of indoor inspection tasks. This paper introduces Ascento, a compact wheeled bipedal robot that is able to move quickly on flat terrain, and to overcome obstacles by jumping. The mechanical design and overall architecture of the system is presented, as well as the development of various controllers for different scenarios. A series of experiments with the final prototype system validate these behaviors in realistic scenarios.

/pdf/ascento-a-two-wheeled-jumping-robot-52lo4gjhru.pdf

Ascento: A Two-Wheeled Jumping Robot

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

For centuries, scientists have explored the limits of biological jump height1,2, and for decades, engineers have designed jumping machines3-18 that often mimicked or took inspiration from biological jumpers. Despite these efforts, general analyses are missing that compare the energetics of biological and engineered jumpers across scale. Here we show how biological and engineered jumpers have key differences in their jump energetics. The jump height of a biological jumper is limited by the work its linear motor (muscle) can produce in a single stroke. By contrast, the jump height of an engineered device can be far greater because its ratcheted or rotary motor can 'multiply work' during repeated strokes or rotations. As a consequence of these differences in energy production, biological and engineered jumpers should have divergent designs for maximizing jump height. Following these insights, we created a device that can jump over 30 metres high, to our knowledge far higher than previous engineered jumpers and over an order of magnitude higher than the best biological jumpers. Our work advances the understanding of jumping, shows a new level of performance, and underscores the importance of considering the differences between engineered and biological systems. 

https://authors.library.caltech.edu/114555/33/AbstractLink.pdf

Engineered jumpers overcome biological limits via work multiplication

Jumping is a locomotion strategy widely evolved in both invertebrates and vertebrates. In addition to terrestrial animals, several aquatic animals are also able to jump in their specific environments. In this paper, the state of the art of jumping robots has been systematically analyzed, based on their biological model, including invertebrates (e.g., jumping spiders, locusts, fleas, crickets, cockroaches, froghoppers and leafhoppers), vertebrates (e.g., frogs, galagoes, kangaroos, humans, dogs), as well as aquatic animals (e.g., both invertebrates and vertebrates, such as crabs, water-striders, and dolphins). The strategies adopted by animals and robots to control the jump (e.g., take-off angle, take-off direction, take-off velocity and take-off stability), aerial righting, land buffering, and resetting are concluded and compared. Based on this, the developmental trends of bioinspired jumping robots are predicted.

https://www.mdpi.com/2076-3417/10/23/8607/pdf

Jumping Locomotion Strategies: From Animals to Bioinspired Robots

The jumping–gliding robot is a kind of locomotion platform with the capabilities to jump on the ground and glide through the air. The jumping of this robot has to juggle the requirements of initial velocity and posture for entry to gliding and progressing on the ground. Inspired by flying squirrels, we proposed the concept of flexible wing-limb blending platform and designed a robot with two jumping modes. The robot can takeoff with different speeds and stances, and adjust aerial posture using the swing of forelimbs. To the best of our knowledge, this is the first miniature and bio-inspired jumping robot that can autonomically change the speeds and stances when takeoff. Experimental results show that the robot can takeoff at about 3 m/s and pitch angle of 0° in the mode of jumping for gliding and adjust the pitch angle at the top to 0°~10° by actuating the forelimbs swing according to the requirement of gliding. In the mode of jumping for progress, the robot can takeoff at about 2 m/s with a pitch angle of 20° and then intermittently jump with a distance of 0.37 m of once jump and an average progress speed of 0.2 m/s. The robot presented in this paper lays the foundation for the development of flexible wing-limb blending platform, which is capable of jumping and gliding.

Design and Demonstration of a Flying-Squirrel-Inspired Jumping Robot with Two Modes

While exploring complex environments, conventional mobile robots can overcome obstacles of limited height and jumping robots can overcome obstacles several times their own size. When jumping motion...

https://journals.sagepub.com/doi/pdf/10.1177/1729881417745608

Wheeled hopping robot with combustion-powered actuator:

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:

In order to solve the conflict of energy utilization and dynamic performance in the underwater robot, this paper proposes a new structure of it. The underwater robot in the paper has two motion modes, cruise mode and tracking mode. In its cruise mode, straight-swimming, turning-swimming, burst, rising and diving are realized like a fish. It has a three -DOF biomimetic tail which can simulate fish swimming. In tracking mode, it can also realize the motion in the cruise mode, but it is thrusted by propellers. So it has a powerful motivation and can swim more smoothly and faster. And it also benefits to use camera to trace targets. We use modular design in it. Each part of the robot can be disassembled. Furthermore, the paper also deals with the motion control of the robot. By the two motion modes, the conflict of energy utilization and dynamic performance is solved. The paper finally proves the superiority of the underwater robot’s performance through experiments.

Design and Motion control of a Small Underwater Robot

Conventional jumping robot can only perform jumping motion on land while the amphibious jumping robot under development is capable of jumping and overcoming obstacles in both terrestrial and aquatic environment. This robot‘s outstanding jumping ability are due to its core component–the water jet thruster. In this paper, we introduce a novel water jet thruster powered by liquid nitrogen, including its inner structure, working process and prototype manufacture. Next, a mathematical model for the water jet thruster is built to analyse its parameter variations during working process. The relationship between the volume fraction of water inside the thruster and the jumping height of the thruster is also studied, and the result shows that there usually exists an optimum volume fraction of water for a given set pressure. Especially, the optimum volume fraction of water will rise with the growing of the set pressure. Finally the outdoor aquatic experiment is carried out to validate the reasonability of the theoretical analysis and the practicability of the water jet thruster.

Design of a novel water jet thruster for amphibious jumping robot

The invention provides a gas-driving jumping device which comprises a cylinder body, a piston and at least one elastic element, wherein the top end of the cylinder body is sealed by an upper cylinder cover; an opening is formed on the bottom of the cylinder body; the cylinder body is fixedly connected with the upper cylinder cover; a pressure detection port, an exhaust port and an ignition device are arranged on the upper cylinder cover; the ignition device is located on the inner side of the upper cylinder cover; a first level step, a second level step and a third level step are respectively formed in a top-wide bottom-narrow form on an inner side wall of the cylinder body; the exhaust port is controlled by an exhaust solenoid valve; the piston is located in the cylinder body in a drawing form; the piston is hollow; the top of the piston is opening; the bottom of the piston is fixedly connected with a base; a gas inlet is formed on the side wall of the lower part of the base; the gas inlet is controlled by an inlet solenoid valve; a lug boss is arranged at the top end of the piston; the lug boss is connected with the top end of the elastic element; the bottom end of the elastic element is connected with the second level step. The gas-driving jumping device has the advantages that the locking force is large, the gas purity can be effectively ensured, the structure is compact, the mounting and dismounting are convenient, and the gas-driving jumping device has high-efficient ignition device and higher space use rate so that the robot has higher extreme obstacle-crossing ability and higher flexibility and maneuverability.

Jixue Mo

Papers

Wheeled hopping robot with combustion-powered actuator:

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

Design and Motion control of a Small Underwater Robot

Design of a novel water jet thruster for amphibious jumping robot

Gas-driving jumping device