Manoeuvring of an aquatic soft robot using thrust-vectoring

Wang, Tao; Lidtke, Artur Konrad; Giorgio-Serchi, Francesco; Weymouth, Gabriel

doi:10.1109/robosoft.2019.8722732

Cited by 9 publications

(10 citation statements)

References 31 publications

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“…For example, a 3D-printed nozzle with a fixed angle relative to the long axis of a cephalopod-inspired robot made with compliant ribs reached a turning rate up to 50 deg per second (Christianson et al 2020). Excellent turning maneuverability by cephalopod-inspired soft robots capable of thrust vectoring was also reported by Wang et al (2019) and Zhang et al (2020a).…”

Section: Introductionmentioning

confidence: 91%

Thrust and torque production of a squid-inspired swimmer with a bent nozzle for thrust vectoring

2022

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A three-dimensional pulsed-jet propulsion model consisting of a flexible body and a steerable bent nozzle in tethered mode is presented and studied numerically. By prescribing the body deformation and nozzle angle, we examine the flow evolution and propulsive/turning performance via thrust vectoring. Our results show that the vortex ring is no longer axis-symmetric when the jet is ejected at an angle with the incoming flow. A torque peak is observed during jetting, which is mainly sourced from the suction force (negative pressure) at the lower part of the internal nozzle surface when the flow is directed downward through an acute angle. After this crest, the torque is dominated by the positive pressure at the upper part of the internal nozzle surface, especially at a relatively low jet-based Reynolds number (О(102)). The torque production increases with a larger nozzle bent angle as expected. Meanwhile, the thrust production remains almost unchanged, showing little trade-off between thrust and torque production which demonstrates the advantage of thrust vectoring via a bent nozzle. By decoupling the thrust at the internal and outer surfaces considering special characteristics of force generation by pulsed-jet propulsion, we find that variations in Reynolds number mostly affect the viscous friction at the outer surfaces. The influence of the maximum stroke ratio is also studied. Results show that both the time-averaged thrust and the torque decrease at a larger stroke ratio.

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Section: Introductionmentioning

confidence: 91%

Thrust and torque production of a squid-inspired swimmer with a bent nozzle for thrust vectoring

2022

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“…In fact, its limit is comparable, if not higher than fish [18]. Previous research on jet propulsion in cephalopod-inspired robots with deformable bodies was pre-strained and released by hand [19], employed tendon-driven contraction of a soft shell [20,21], used a lead-screw and snap catch to elastically store and quickly release energy [22], or hydraulically inflated a soft shell [23,24]. The ultrafast escape maneuver demonstrated by hyperinflation of the body achieved high acceleration with a collapsible body, but the motion was not cyclic as it had to be manually pressurized for each trial [19].…”

Section: Introductionmentioning

confidence: 99%

“…To enable free swimming, we developed and implemented a waterproof power supply, resulting in a top speed of 18.4 cm s −1 , corresponding to 0.54 body lengths/s (BL/s), and maximum instantaneous speed of 32.1 cm s −1 (0.94 BL/s). Additionally, we tested nozzles with different orientations with respect to the long axis of the robot to demonstrate turning maneuvers through thrust vectoring [24]. This locomotion strategy may enable effective propulsion without a propeller, reducing the risk of the propulsion system of the robot to get ensnared or to cause damage to objects in its environment.…”

Section: Introductionmentioning

confidence: 99%

Cephalopod-inspired robot capable of cyclic jet propulsion through shape change

Christianson¹,

Cui²,

Ishida³

et al. 2020

Bioinspir. Biomim.

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The compliance and conformability of soft robots provide inherent advantages when working around delicate objects or in unstructured environments. However, rapid locomotion in soft robotics is challenging due to the slow propagation of motion in compliant structures, particularly underwater. Cephalopods overcome this challenge using jet propulsion and the added mass effect to achieve rapid, efficient propulsion underwater without a skeleton. Taking inspiration from cephalopods, here we present an underwater robot with a compliant body that can achieve repeatable jet propulsion by changing its internal volume and cross-sectional area to take advantage of jet propulsion as well as the added mass effect. The robot achieves a maximum average thrust of 0.19 N and maximum average and peak swimming speeds of 18.4 cm s−1 (0.54 body lengths/s) and 32.1 cm s−1 (0.94 BL/s), respectively. We also demonstrate the use of an onboard camera as a sensor for ocean discovery and environmental monitoring applications.

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“…However, these nozzles are prefabricated rigid ones that are not adjustable during operation. A swimmer with steerable nozzle has been developed and its maneuverability has been demonstrated in tests [83]. Adjustable nozzles with more degrees of freedom, such as those activated by shape memory alloys [84], will be useful for this purpose.…”

Section: Discussionmentioning

confidence: 99%

Physics and applications of squid-inspired jetting

Zhu

Xiao

2022

Bioinspir. Biomim.

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In the aquatic world jet propulsion is a highly successful locomotion method utilized by a variety of species. Among them cephalopods such as squids excel in their ability for high-speed swimming. This mechanism inspires the development of underwater locomotion techniques which are particularly useful in soft-bodied robots. In this overview we summarize existing studies on this topic, ranging from investigations on the underlying physics to the creation of mechanical systems utilizing this locomotion mode. Research directions that worth future investigation are also discussed.

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Manoeuvring of an aquatic soft robot using thrust-vectoring

Cited by 9 publications

References 31 publications

Thrust and torque production of a squid-inspired swimmer with a bent nozzle for thrust vectoring

Thrust and torque production of a squid-inspired swimmer with a bent nozzle for thrust vectoring

Cephalopod-inspired robot capable of cyclic jet propulsion through shape change

Physics and applications of squid-inspired jetting

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