1,721,014 research outputs found
Soft Robotics in Underwater Legged Locomotion: From Octopus–Inspired Solutions to Running Robots
No full textModel-based open loop control of a multigait legged underwater robot
No full textIn this paper a model-based open loop control of SILVER, a multigait legged underwater vehicle for the benthic zone exploration, is presented. The contributions of underwater environment are taken into account by resorting to a recently introduced fundamental model of monopedal underwater hopping locomotion on which the tuning of a completely open loop control algorithm for dynamic gaits is based. The design of the robot and the control algorithm of each gait are presented along with experimental results which demonstrate on-spot static and dynamic rotation, and forward locomotion by crawling, walking and hopping. Moreover, for the first time the behavior of multi-legged underwater robots is grounded to the fundamental monopedal model. SILVER is the first underwater legged robot capable of performing dynamic self-stabilizing hopping gaits together with static gaits and precise foot placement. Thanks to its unique features the category of underwater legged robots has the potential to be a very versatile and valuable alternative to the existing technology for the exploration of the seabed
Bioinspired locomotion and grasping in water: the soft eight-arm OCTOPUS robot
No full textThe octopus is an interesting model for the development of soft robotics, due to its high deformability, dexterity and rich behavioural repertoire. To investigate the principles of octopus dexterity, we designed an eight-arm soft robot and evaluated its performance with focused experiments. The OCTOPUS robot presented here is a completely soft robot, which integrates eight arms extending in radial direction and a central body which contains the main processing units. The front arms are mainly used for elongation and grasping, while the others are mainly used for locomotion. The robotic octopus works in water and its buoyancy is close to neutral. The experimental results show that the octopus-inspired robot can walk in water using the same strategy as the animal model, with good performance over different surfaces, including walking through physical constraints. It can grasp objects of different sizes and shapes, thanks to its soft arm materials and conical shape
Dynamics of underwater legged locomotion: Modeling and experiments on an octopus-inspired robot
No full textDynamic Model of a Multibending Soft Robot Arm Driven by Cables
No full textThe new and promising field of soft robotics has many open areas of research such as the development of an exhaustive theoretical and methodological approach to dynamic modeling. To help contribute to this area of research, this paper develops a dynamic model of a continuum soft robot arm driven by cables and based upon a rigorous geometrically exact approach. The model fully investigates both dynamic interaction with a dense medium and the coupled tendon condition. The model was experimentally validated with satisfactory results, using a soft robot arm working prototype inspired by the octopus arm and capable of multibending. Experimental validation was performed for the octopus most characteristic movements: bending, reaching, and fetching. The present model can be used in the design phase as a dynamic simulation platform and to design the control strategy of a continuum robot arm moving in a dense medium
Morphologically induced stability on an underwater legged robot with a deformable body
Full text linkFor robots to navigate successfully in the real-world, unstructured environment adaptability is a prerequisite. While this is typically implemented within the control layer, there have been recent proposals of adaptation through a morphing of the body. However, the successful demonstration of this approach has mostly been theoretical and in simulations thus far. In this work we present an underwater hopping robot that features a deformable body implemented as adeployable structure which is covered by a soft skin for which it is possible to manually change the body size without altering any other property (e.g. buoyancy or weight). For such a system, we show that it is possible to induce a stable hopping behaviour instead of a fall, by just increasing the body size. We provide a mathematical model that describes the hopping behaviour of the robot under the influence of shape-dependent underwater contributions (drag, buoyancy and added mass) in order to analyse and compare the results obtained. Moreover, we show that for certain conditions, a stable hopping behaviour can only be obtained through changing the morphology of the robot as the controller (i.e. actuator) would already be working at maximum capacity. The presented work demonstrates that, through the exploitation of shape-dependent forces, the dynamics of a system can be modified through altering the morphology of the body to induce a desirable behaviour and, thus, a morphological change can be an effective alternative to the classic control
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