scholarly journals Deep Reinforcement Learning-Based Robotic Grasping in Clutter and Occlusion

2021 ◽  
Vol 13 (24) ◽  
pp. 13686
Author(s):  
Marwan Qaid Mohammed ◽  
Lee Chung Kwek ◽  
Shing Chyi Chua ◽  
Abdulaziz Salamah Aljaloud ◽  
Arafat Al-Dhaqm ◽  
...  
Keyword(s):  
Visual Observation ◽  
Robotic Manipulation ◽  
Experimental Simulation ◽  
Multiple Views ◽  
Robotic Grasping ◽  
Visual Change ◽  
Depth Difference ◽  
Set Up ◽  
Partially Occluded ◽  
View Change

In robotic manipulation, object grasping is a basic yet challenging task. Dexterous grasping necessitates intelligent visual observation of the target objects by emphasizing the importance of spatial equivariance to learn the grasping policy. In this paper, two significant challenges associated with robotic grasping in both clutter and occlusion scenarios are addressed. The first challenge is the coordination of push and grasp actions, in which the robot may occasionally fail to disrupt the arrangement of the objects in a well-ordered object scenario. On the other hand, when employed in a randomly cluttered object scenario, the pushing behavior may be less efficient, as many objects are more likely to be pushed out of the workspace. The second challenge is the avoidance of occlusion that occurs when the camera itself is entirely or partially occluded during a grasping action. This paper proposes a multi-view change observation-based approach (MV-COBA) to overcome these two problems. The proposed approach is divided into two parts: 1) using multiple cameras to set up multiple views to address the occlusion issue; and 2) using visual change observation on the basis of the pixel depth difference to address the challenge of coordinating push and grasp actions. According to experimental simulation findings, the proposed approach achieved an average grasp success rate of 83.6%, 86.3%, and 97.8% in the cluttered, well-ordered object, and occlusion scenarios, respectively.

Mechanisms for Robotic Grasping and Manipulation

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Vincent Babin ◽  
Clément Gosselin
Keyword(s):  
Online Publication ◽  
Autonomous Systems ◽  
Robotic Manipulation ◽  
Annual Review ◽  
Publication Date ◽  
Robotic Grasping ◽  
Grasp Planning ◽  
Grasping And Manipulation

This article reviews the literature on the design of robotic mechanical grippers, with a focus on the mechanical aspects, which are believed to be the main bottleneck for effective designs. Our discussion includes gripper architectures and means of actuation, anthropomorphism and grasp planning, and robotic manipulation, emphasizing the complementary concepts of intrinsic and extrinsic dexterity. We also consider interactions of robotic grippers with the environment and with the objects to be grasped and argue that the proper handling of such interactions is key to the development of grasping and manipulation tools and scenarios. Finally, we briefly present examples of recent designs to support the discussion. Expected final online publication date for the Annual Review of Control, Robotics, and Autonomous Systems, Volume 4 is May 3, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Evaluation of pheromone trapping of diamondback moth (Plutella xylostella) as a tool for monitoring larval infestations in cabbage crops in Samoa

2007 ◽  
Vol 25 (1) ◽  
pp. 43 ◽  
Author(s):  
J.B. Sulifoa ◽  
A.A. Ebenebe
Keyword(s):  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Visual Observation ◽  
Pheromone Traps ◽  
Weekly Basis ◽  
Pheromone Trapping ◽  
Set Up

Studies were conducted at Aleisa and Alafua in Samoa, during 2004/2005, to assess the propriety of using pheromone trapping of Plutella xylostella as a tool for monitoring larval infestations in cabbage crops. Numbers of adults and larvae of P. xylostella present in cabbage crops were monitored, concurrently, on a weekly basis at the two sites over a period of 13 and 15 months, respectively. Numbers of P. xylostella adults were monitored by using pheromone traps which were set up in cabbage fields, whereas numbers of larvae were monitored through visual observation of cabbage plants in the same fields where the pheromone traps were placed. Results showed that numbers of P. xylostella adults caught in pheromone traps were positively correlated with larval infestations in the crops (r = 0.894 for Aleisa, r = 0.589 for Alafua). Number of moths caught in traps explained 79.9% and 34.4% of variation in larval infestations at Aleisa and Alafua, respectively.

OBJECT DETECTION AND TRACKING IN REAL TIME ENVIRONMENT WITH DIFFERENT COLOUR BACKGROUND IN EUCLIDEAN COLOR FILTER

2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Trapti Mala Mishra ◽  
Md. Amzad Quazi
Keyword(s):  
Visual Observation ◽  
Paper Analysis ◽  
Video Observation ◽  
Color Filter ◽  
Detection And Tracking ◽  
Color Detection ◽  
Colored Background ◽  
Transient Data ◽  
Set Up ◽  
Normal Background

The innovation of moving item is imperative in numerous undertakings, for example, video reconnaissance and moving article following. In this paper, an audit has been made on a video reconnaissance situation with constant moving item identification and following. The configuration of a video observation framework is coordinated on programmed distinguishing proof of occasions of interest, particularly on following and arrangement of moving articles. The article following and discovery is utilized to set up a correspondence between items or article parts in continuous edges and to concentrate transient data about items, for example, direction, stance, speed and direction. Tracking is distinguishing the items outline by edge in video. It can be utilized as a part of numerous districts, for example, video reconnaissance, movement checking and individuals following. In static environment division of article is not complex. In element environment because of element ecological conditions, for example, brightening changes, shadows and waving tree limbs in the wind object division is a troublesome and noteworthy issue that should be taken care of well for a powerful visual observation framework. In this paper analysis of different colored object in different colored background with the help of Euclidean color filter and compare normal background with different lightening condition. In this work, we analysis the detection capability of filter in same color  with different lightening condition  background and find out the range of color detection by the filter.

scholarly journals RGB-D object detection and semantic segmentation for autonomous manipulation in clutter

2017 ◽  
Vol 37 (4-5) ◽  
pp. 437-451 ◽  
Author(s):  
Max Schwarz ◽  
Anton Milan ◽  
Arul Selvam Periyasamy ◽  
Sven Behnke
Keyword(s):  
Object Detection ◽  
Disaster Response ◽  
Semantic Segmentation ◽  
Object Perception ◽  
Robotic Manipulation ◽  
Learning Approach ◽  
Fusion Method ◽  
Autonomous Manipulation ◽  
Complex Scenes ◽  
Partially Occluded

Autonomous robotic manipulation in clutter is challenging. A large variety of objects must be perceived in complex scenes, where they are partially occluded and embedded among many distractors, often in restricted spaces. To tackle these challenges, we developed a deep-learning approach that combines object detection and semantic segmentation. The manipulation scenes are captured with RGB-D cameras, for which we developed a depth fusion method. Employing pretrained features makes learning from small annotated robotic datasets possible. We evaluate our approach on two challenging datasets: one captured for the Amazon Picking Challenge 2016, where our team NimbRo came in second in the Stowing and third in the Picking task; and one captured in disaster-response scenarios. The experiments show that object detection and semantic segmentation complement each other and can be combined to yield reliable object perception.

scholarly journals Experimental Simulation of Solar Aqua Lens Concentrator

2019 ◽  
Vol 9 (2) ◽  
pp. 1591-1594
Keyword(s):  
Concentration Ratio ◽  
Focal Point ◽  
Tap Water ◽  
Focal Length ◽  
Experimental Simulation ◽  
Radius Of Curvature ◽  
Sugar Solution ◽  
Hyper Elastic ◽  
Set Up ◽  
Auto Cad

The lens was built from readily available materials in the market. The liquid used in lenses were tap water, 30% sugar solution in the hyper elastic low density polyethylene foil. The experimental set up was exposed to sunlight. The focal length point and light intensities were measured at that focal point spot, concentration ratio at each focal point was calculated. The concentration ratio is inversely proportional to focal point. The experimental data was tabulated. The theoretical lens radius of curvature and deformation of lens was validated by ANSYS finite Element Modeling (FEM).The lens deformation of hyper elastic foil was also compare with AUTO CAD. Solar aqua concentrator can be used where high focusing thermal application is required.

scholarly journals Design, Modeling and Control of Bionic Knee in Artificial Leg

2019 ◽  
Vol 14 (5) ◽  
pp. 733
Author(s):  
Hualong Xie ◽  
Yao Xie ◽  
Fei Li
Keyword(s):  
Sliding Mode ◽  
Biped Robot ◽  
Experimental Simulation ◽  
Driving Mechanism ◽  
Modeling And Control ◽  
Driving Mode ◽  
Leg Muscles ◽  
Lower Limb Prosthesis ◽  
Set Up ◽  
And Control

The biped robot with heterogeneous legs (BRHL) greatly facilitates the development of intelligent lower-limb prosthesis (ILLP). In the BRHL, the remaining leg of the amputee is simulated by an artificial leg, which provides the bionic leg with the precise gait following trajectory. Therefore, the artificial leg must closely mimic the features of the human leg. After analyzing the motion mechanism of the human knee, this paper designs a four-link bionic knee in light of the coexistence of rolling and sliding between the femur, the meniscus and the tibia. Drawing on the driving mechanism of leg muscles, two pneumatic artificial muscles (PAMs) were adopted to serve as the extensor and flexor muscles on the thigh. The two PAMs move in opposite direction, driving the knee motions in the artificial leg. To overcome the complexity of traditional PAM modelling methods, the author set up a PAM feature test platform to disclose the features of the PAMs, and built static and dynamic nonlinear mathematical models of the PAMs based on the test data. Next, a proportional-integral-derivative (PID) closed loop controller and sliding mode controller was designed for the bionic knee, referring to the kinetics equation of the knee. Through experimental simulation, it is confirmed that the proposed controller can accurately control the position of the four-link bionic knee, and that the designed bionic knee and PAM driving mode are both correct.

scholarly journals Effects of Voltage Dips on Robotic Grasping

Robotics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 28 ◽  
Author(s):  
Giuseppe Carbone ◽  
Marco Ceccarelli ◽  
Christopher Fabrizi ◽  
Pietro Varilone ◽  
Paola Verde
Keyword(s):  
Electric Power ◽  
Power Quality ◽  
Experimental Tests ◽  
Robotic Hand ◽  
Robotic Grasping ◽  
Voltage Dip ◽  
Electric Power Quality ◽  
Voltage Dips ◽  
Set Up

This paper addresses the effects of electric power quality on robotic operations. A general overview is reported to highlight the main characteristics of electric power quality and it’s effects on a powered system by considering an end-user’s viewpoint. Then, the authors outline the influence of voltage dip effects by focusing on robotic grasping applications. A specific case study is reported, namely that of LARM Hand IV, a three-fingered robotic hand which has been designed and built at LARM in Cassino, Italy. A dedicated test rig has been developed and set up to generate predefined voltage dips. Experimental tests are carried out to evaluate the effects of different types of voltage dip on the grasping of objects.

scholarly journals In-vitro sonothrombolysis using thick-shelled polymer microbubbles - a comparison with thin-shelled microbubbles

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Jovana Janjic ◽  
Malin K Larsson ◽  
Anna Bjällmark
Keyword(s):  
Drug Delivery ◽  
Mass Loss ◽  
Low Pressure ◽  
Clot Lysis ◽  
Ultrasound Exposure ◽  
Blood Clots ◽  
Upstream Pressure ◽  
Set Up ◽  
Partially Occluded

Abstract Background Vascular thrombosis can be treated pharmacologically, however, serious shortcomings such as bleeding may occur. Several studies suggest that sonothrombolysis can induce lysis of the clots using ultrasound. Moreover, intravenously injected thin-shelled microbubbles (MBs) combined with ultrasound can further improve clot lysis. Thick-shelled MBs have been used for drug delivery, targeting and multimodal imaging. However, their capability to enhance sonothrombolysis is unknown. In this study, using an in-vitro set-up, the enhancement of clot lysis using ultrasound and thick-shelled MBs was investigated. Thin-shelled MBs was used for comparison. Method The main components in the in-vitro set-up was a vessel mimicking phantom, a pressure mearing system and programmable ultrasound machine. Blood clots were injected and entrapped on a pore mesh in the vessel phantom. Four different protocols for ultrasound transmission and MB exposure (7 blood clots/protocol) were considered together with a control test were no MBs and ultrasound were used. For each protocol, ultrasound exposure of 20 min was used. The upstream pressure of the partially occluded mesh was continuously measured to assess clot burden. At the end of each protocol blood clots were removed from the phantom and the clot mass loss was computed. Results For the thick-shelled MBs no difference in clot mass loss compared with the control tests was found. A 10% increase in the clot mass loss compared with the control tests was found when using thin-shelled MBs and low pressure/long pulses ultrasound exposure. Similarly, in terms of upstream pressure over exposure time, no differences were found when using the thick-shelled MBs, whereas thin-shelled MBs showed a 15% decrease achieved within the first 4 min of ultrasound exposure. Conclusion No increase in clot lysis was achieved using thick-shelled MBs as demonstrated by no significant change in clot mass or upstream pressure. Although thick-shelled MBs are promising for targeting and drug delivery, they do not enhance clot lysis when considering the ultrasound sequences used in this study. On the other hand, ultrasound in combination with thin-shelled MBs can facilitate thrombolysis when applying long ultrasound pulses with low pressure.

scholarly journals Assessment of Phytoviral Status of some New Plum Orchards Established in Iaşi County, Romania

2020 ◽  
Vol 77 (2) ◽  
pp. 155
Author(s):  
Ioan ZAGRAI ◽  
Luminița ZAGRAI ◽  
Georgeta GUZU
Keyword(s):  
Czech Republic ◽  
Visual Observation ◽  
The Other ◽  
High Rate ◽  
Planting Material ◽  
Infected Tree ◽  
Set Up

Four young plum orchards from Iaşi county, two of these established by using propagated material in Romania, and the other two with material from Austria, Czech Republic and Netherlands, were surveyed by visual observation of viral symptoms. Then, trees were sampled and tested for the presence of six viruses (PPV, PDV, PNRSV, ACLSV, ApMV and MLRSV) by serologic assays. A high rate of PPV infection (78% and 79%, respectively) was determinated in the two orchards established with planting material propagated in Romania, and a rate of 5% PDV infection was found in one of them. A rate of 2.5% PPV infection was determined in the orchard established with propagated material in Austria and Czech Republic, and no PPV infected tree was found in the orchard set up with material propagated in Netherlands. The infections with PNRSV, ACLSV, ApMV and MLRSV were not detected in the four orchards surveyed.

scholarly journals Experimental Simulation of the Behaviour of Diagnostic First Mirrors Fabricated of Different Metals for ITER Conditions

2016 ◽  
Vol 3 (1) ◽  
pp. 23-54 ◽  
Author(s):  
V.S. Voitsenya ◽  
A.F. Bardamid ◽  
A.J.H. Donné
Keyword(s):  
Operating Conditions ◽  
Experimental Simulation ◽  
Science Center ◽  
Plasma Facing Component ◽  
Laser Diagnostic ◽  
Set Up ◽  
The Impact ◽  
Experimental Fusion

In the experimental fusion reactor ITER, the plasma-facing component of each optical and/or laser diagnostic needs to be based on reflective optics with at least one mirror (first mirror) facing the thermonuclear plasma. The different kinds of radiation emanating from the burning plasma (neutrons, neutral atoms, electromagnetic radiation) create hostile operating conditions for the first mirrors. Therefore, a special program has been set up under the ITER framework aimed at solving the first mirror problem. This paper will review the main results in this field that have been obtained in the Institute of Plasma Physics, National Science Center “Kharkov Institute of Physics and Technology” (in many cases in cooperation with groups of other countries, as indicated in corresponding parts of the manuscript) during long-term investigations directed to find a solution of this problem,i.e., to find a material and accompanying precautions in order to satisfy the requirements for first mirrors. The main efforts were devoted to finding solutions to overcome the impact of the most severe deteriorating factors resulting in degradation of the optical properties of mirrors: sputtering by charge exchange atoms and deposition of contaminants. The obtained results are focused on: the effects of long term sputtering on mirror specimens fabricated from different metals with different structures (polycrystals, single crystals, metal film on metal substrates, amorphous), the effects of contaminating film and the possible protection to avoid of its appearance, the role of chemical processes for some metal mirrors, and the choice of material of laser mirrors.

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