Surveying and cleaning plastic pollution in the sediment: SILVER+ approach

Picardi, Giacomo; Chellapurath, Mrudul; Iacoponi, Saverio; Laschi, Cecilia

doi:10.1109/oceanse.2019.8867331

Cited by 8 publications

(5 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the present study, when the crab needs its legs to be in contact with the ground for longer time during the SFP gait, it orients its carapace with a positive pitch angle to possibly create a wedging effect and push the body towards the ground. This strategy could be used in underwater legged robots like SILVER 2.0 [36] to increase tenacity by adjusting the orientation of its body with a bioinspired shell.…”

Section: Kinematics Are Modified Due To Fluid Forcesmentioning

confidence: 99%

Locomotory behaviour of the intertidal marble crab (Pachygrapsus marmoratus) supports the underwater spring-loaded inverted pendulum as a fundamental model for punting in animals

Chellapurath¹,

Stefanni²,

Fiorito³

et al. 2020

Bioinspir. Biomim.

Self Cite

View full text Add to dashboard Cite

In aquatic pedestrian locomotion the dynamics of terrestrial and aquatic environments are coupled. Here we study terrestrial running and aquatic punting locomotion of the marine-living crab Pachygrapsus marmoratus. We detected both active and passive phases of running and punting through the observation of crab locomotory behaviour in standardized settings and by three-dimensional kinematic analysis of its dynamic gaits using high-speed video cameras. Variations in different stride parameters were studied and compared. The comparison was done based on the dimensionless parameter the Froude number (Fr) to account for the effect of buoyancy and size variability among the crabs. The underwater spring-loaded inverted pendulum (USLIP) model better fitted the dynamics of aquatic punting. USLIP takes account of the damping effect of the aquatic environment, a variable not considered by the spring-loaded inverted pendulum (SLIP) model in reduced gravity. Our results highlight the underlying principles of aquatic terrestrial locomotion by comparing it with terrestrial locomotion. Comparing punting with running, we show and increased stride period, decreased duty cycle and orientation of the carapace more inclined with the horizontal plane, indicating the significance of fluid forces on the dynamics due to the aquatic environment. Moreover, we discovered periodicity in punting locomotion of crabs and two different gaits, namely, long-flight punting and short-flight punting, distinguished by both footfall patterns and kinematic parameters. The generic fundamental model which belongs to all animals performing both terrestrial and aquatic legged locomotion has implications for control strategies, evolution and translation to robotic artefacts.

show abstract

Section: Kinematics Are Modified Due To Fluid Forcesmentioning

confidence: 99%

Locomotory behaviour of the intertidal marble crab (Pachygrapsus marmoratus) supports the underwater spring-loaded inverted pendulum as a fundamental model for punting in animals

Chellapurath¹,

Stefanni²,

Fiorito³

et al. 2020

Bioinspir. Biomim.

Self Cite

View full text Add to dashboard Cite

show abstract

“…SILVER2 is a medium-sized robot, featuring the same leg arrangement of CR200, but significantly smaller and lighter. It was originally developed as a novel tool to collect sunken litter and sample microplastics in the sediment [146], but it can be considered as a general-purpose tool for operations on the seabed. With respect to the previously discussed prototypes, which only rely on static walking gaits, SILVER2 was designed to also perform punting locomotion, a form of underwater hopping gait observed in crabs [94].…”

Section: Ulrs Tested In the Fieldmentioning

confidence: 99%

“…Military applications such as mine countermeasure in the surf zone was proposed for both RoboLobster [88] and Ariel [84]. Subsea cable wrenching was envisioned for the hydraulically actuated Hexaterra [103], while CR200 was developed for working under strong current disturbances [74], and SILVER2 for underwater litter collection [146]. Additionally, the unique capabilities demonstrated by ULRs will open notable application scenarios in ecological monitoring and sampling [13].…”

Section: Applications Of Ulr In Marine Science and Space Explorationmentioning

confidence: 99%

Underwater legged robotics: review and perspectives

et al. 2023

View full text Add to dashboard Cite

Nowadays, there is a growing awareness on the social and economic importance of the ocean. In this context, being able to carry out a diverse range of operations underwater is of paramount importance for many industrial sectors as well as for marine science and to enforce restoration and mitigation actions. Underwater robots allowed us to venture deeper and for longer time into the remote and hostile marine environment. However, traditional design concepts such as propeller driven Remotely Operated Vehicles (ROVs), Autonomous Underwater Vehicles (AUVs), or tracked benthic crawlers, present intrinsic limitations, especially when a close interaction with the environment is required. An increasing number of researchers are proposing legged robots as a bioinspired alternative to traditional designs, capable of yielding versatile multi-terrain locomotion, high stability, and low environmental disturbance. In this work, we aim at presenting the new field of underwater legged robotics in an organic way, discussing the prototypes in the state-of-the-art and highlighting technological and scientific challenges for the future. First, we will briefly recap the latest developments in traditional underwater robotics from which several technological solutions can be adapted, and on which the benchmarking of this new field should be set. Second, we will the retrace the evolution of terrestrial legged robotics, pinpointing the main achievements of the field. Third, we will report a complete state of the art on Underwater Legged Robots (ULRs) focusing on the innovations with respect to the interaction with the environment, sensing and actuation, modelling and control, and autonomy and navigation. Finally, we will thoroughly discuss the reviewed literature by comparing traditional and legged underwater robots, highlighting interesting research opportunities, and presenting use case scenarios derived from marine science applications.

show abstract

“…An ongoing project for autonomous cleaning of oceans is the Rozalia Project, which focuses both on innovation and education programs [24]. A crab-inspired vehicle was proposed by Picardi et al [25].…”

Section: B Use Of Auvs For Marine Debrismentioning

confidence: 99%

Towards More Efficient EfficientDets and Real-Time Marine Debris Detection

Zocco

Huang

Wang

et al. 2023

IEEE Robot. Autom. Lett.

View full text Add to dashboard Cite

Colab CPU, a Colab GPU (which is either a Tesla P100 or 230 a Tesla T4), an Nvidia Jetson Xavier and a Nvidia Jetson 231 Nano: the server GPU is the fastest followed by the Xavier, 232 the Nano and the server CPU. The same ranking occurs for 233 the scaling ratio: D3(1-5) is 3.2 times slower than D0(1-234 5) with the server GPU, 5.3 times slower with the Xavier, 235 6.3 times slower with the Nano and 7.9 times slower with 236 the server CPU. Therefore, a more powerful GPU has a 237 double benefit: smaller runtimes and smaller scaling ratios; 238 however, the full-fledged GPUs used in large clusters cannot 239 be installed on underwater robots due to energy, space and 240 weight constraints. 241 B. On Marine Debris Datasets 242 Subsequently, we trained our improved EfficientDets on 243 the first 1200 samples of the Trash-ICRA19 [11], which is 244 a publicly available annotated dataset for object detection 245 targeting three classes: "bio" for biological items, "plastic" 246 for plastic items and "rov" for remotely operated vehicles. 247 The results are in Table VI, where 35 epochs have been 248 chosen for demonstration purposes; when training a model 249 for deployment on an AUV, the number of epochs should 250 be increased in order to reach the learning saturation. With 251 35 epochs, we reached 47.4% AP with D0 and 49.6% AP 252 289 4; most of the samples of WPBB are taken at more than 290 a meter of distance from the object, hence most of the 291 pixels are background; some samples of WPBB have low 292 resolution because captured while the drone was steering. 293 All these factors make the WPBB dataset both challenging 294 and realistic. Examples of detections are shown in Fig. 4 295 with different values of confidence threshold τ , which is an 296 hyperparameter meaning that detections with a confidence 297 lower than τ are ignored: the plastic bag is detected by all 298 the four detectors with high confidence, but its detection is 299 relatively easy since it is well visible; in contrast, one of the 300 two floating bottles at the top is detected only by D0 with 301 just a 43% confidence. 302 C. Evaluations on Simulator 303 Given that underwater data were expensive to collect, 304 we further carried out reproducible simulation evaluations 305 using the proposed D2(1-5). The simulation in Unity 3D 306 engine provided realistic visual effects and labor-free ground 307 truth labeling. The general setup is similar to our previ-308 ous work [27]. The system included two simulators: Unity 309 (virtual reality (VR) side) and Gazebo (robot side). In the 310 current study, the VR side was involved to transfer real-311 time realistic images rendered by the Unity 3D engine to 312 the object detector. Both Unity and Gazebo included its own 313 virtual vehicle, i.e., a boat equipped with an underwater 314 camera. The robot side was designed to switch either via 315 the Gazebo simulation or a real robot. The robot side 316 included an object detection module running the D2(1-5) 317 model, a navigation and control module pe...

show abstract

Surveying and cleaning plastic pollution in the sediment: SILVER+ approach

Cited by 8 publications

References 25 publications

Locomotory behaviour of the intertidal marble crab (Pachygrapsus marmoratus) supports the underwater spring-loaded inverted pendulum as a fundamental model for punting in animals

Locomotory behaviour of the intertidal marble crab (Pachygrapsus marmoratus) supports the underwater spring-loaded inverted pendulum as a fundamental model for punting in animals

Underwater legged robotics: review and perspectives

Towards More Efficient EfficientDets and Real-Time Marine Debris Detection

Contact Info

Product

Resources

About