164 research outputs found
Strain-tunable magnetic and electronic properties of monolayer CrI3
Two-dimensional CrI3 has attracted much attention as it is reported to be a
ferromagnetic semiconductor with the Curie temperature around 45K. By
performing first-principles calculations, we find that the magnetic ground
state of CrI3 is variable under biaxial strain. Our theoretical investigations
show that the ground state of monolayer CrI3 is ferromagnetic under
compression, but becomes antiferromagnetic under tension. Particularly, the
transition occurs under a feasible in-plane strain around 1.8%. Accompanied by
the transition of the magnetic ground state, it undergoes a transition from
magnetic-metal to half-metal to half-semiconductor to spin-relevant
semiconductor when strain varies from -15% to 10%. We attribute these
transitions to the variation of the d-orbitals of Cr atoms and the p-orbitals
of I atoms. Generally, we report a series of magnetic and electronic phase
transition in strained CrI3, which will help both theoretical and experimental
researchers for further understanding of the tunable electronic and magnetic
properties of CrI3 and their analogous
Toward Design of a Drip-Stand Patient Follower Robot
A person following robot is an application of service robotics that primarily focuses on human-robot interaction, for example, in security and health care. This paper explores some of the design and development challenges of a patient follower robot. Our motivation stemmed from common mobility challenges associated with patients holding on and pulling the medical drip stand. Unlike other designs for person following robots, the proposed design objectives need to preserve as much as patient privacy and operational challenges in the hospital environment. We placed a single camera closer to the ground, which can result in a narrower field of view to preserve patient privacy. Through a unique design of artificial markers placed on various hospital clothing, we have shown how the visual tracking algorithm can determine the spatial location of the patient with respect to the robot. The robot control algorithm is implemented in three parts: (a) patient detection; (b) distance estimation; and (c) trajectory controller. For patient detection, the proposed algorithm utilizes two complementary tools for target detection, namely, template matching and colour histogram comparison. We applied a pinhole camera model for the estimation of distance from the robot to the patient. We proposed a novel movement trajectory planner to maintain the dynamic tipping stability of the robot by adjusting the peak acceleration. The paper further demonstrates the practicality of the proposed design through several experimental case studies
Prioritized Planning for Target-Oriented Manipulation via Hierarchical Stacking Relationship Prediction
In scenarios involving the grasping of multiple targets, the learning of
stacking relationships between objects is fundamental for robots to execute
safely and efficiently. However, current methods lack subdivision for the
hierarchy of stacking relationship types. In scenes where objects are mostly
stacked in an orderly manner, they are incapable of performing human-like and
high-efficient grasping decisions. This paper proposes a perception-planning
method to distinguish different stacking types between objects and generate
prioritized manipulation order decisions based on given target designations. We
utilize a Hierarchical Stacking Relationship Network (HSRN) to discriminate the
hierarchy of stacking and generate a refined Stacking Relationship Tree (SRT)
for relationship description. Considering that objects with high stacking
stability can be grasped together if necessary, we introduce an elaborate
decision-making planner based on the Partially Observable Markov Decision
Process (POMDP), which leverages observations and generates the least
grasp-consuming decision chain with robustness and is suitable for
simultaneously specifying multiple targets. To verify our work, we set the
scene to the dining table and augment the REGRAD dataset with a set of common
tableware models for network training. Experiments show that our method
effectively generates grasping decisions that conform to human requirements,
and improves the implementation efficiency compared with existing methods on
the basis of guaranteeing the success rate.Comment: 8 pages, 8 figure
CANEAT [automated kitty litter box]
Cleaning up pet waste is a daily activity for breeders. This is especially true for cats, as they use litter boxes to urinate and defecate in. It is important to clean the box frequently, otherwise the stink smell will linger in the room. Having someone, or something, who can clean the boxes frequently would make life much easier for breeders.
Our prototype, CANEAT, aims to automate the cleaning procedure to make life easier for breeders. The product will filter out the waste and store it into a sealed container. This container will prevent the smell from leaking into the rest of the room. Those who are disabled, busy, or travel a lot would also benefit from CANEAT.
The device will be assembled using a microcontroller, detecting sensor, power source, and some 3D-printed components. The prototype will be designed and constructed as a stable device which is strong enough to support all the materials.
Ultimately, our product will have the ability to scoop the waste and clean the litter box for breeders automatically. Using it will be simple, and we will also develop an IOS/Android app to streamline the procedure further
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