A porous electrode model, incorporating particle stress effects, is developed for the electrode kinetic processes in the positive Li(Ni 1/3 Mn 1/3 Co 1/3)O 2 or NMC111 electrode. The model is used to analyze experimental data from galvanostatic intermittent titration technique (GITT) during charging at the beginning of life. The equilibrium potential accounts for the influence of mechanical stress in the electrode particles. While the standard Newman-based model proves unable to capture the dynamic performance of NMC111, the extended model with stress allows good fits of the GITT responses for NMC half cells for a voltage range from 3.7-4.1 V vs Li/Li + at 10°C, 25°C and 40°C. Four physical parameters are extracted to analyze the underlying diffusive, kinetic, thermodynamic and stress phenomena from polarization to relaxation during a GITT transient. Strong dependencies of the kinetic rate constant k, slope of the open-circuit potential curve dE conc /dx pos and stress proportionality factor ϒ stress with lithium concentration are found. The effective diffusion coefficients D s,eff are ∼10 −14-10 −13 cm 2 /s across voltages and temperatures. Diffusion limitation and particle surface stress are more profound at higher voltages and at higher temperatures. This leads to large lithium concentration gradient near particle surface, requiring longer relaxation time during GITT.
Simultaneous Localization and Mapping (SLAM) is one of the most essential techniques in many real-world robotic applications. The assumption of static environments is common in most SLAM algorithms, which however, is not the case for most applications. Recent work on semantic SLAM aims to understand the objects in an environment and distinguish dynamic information from a scene context by performing image-based segmentation. However, the segmentation results are often imperfect or incomplete, which can subsequently reduce the quality of mapping and the accuracy of localization. In this paper, we present a robust multi-modal semantic framework to solve the SLAM problem in complex and highly dynamic environments. We propose to learn a more powerful object feature representation and deploy the mechanism of looking and thinking twice to the backbone network, which leads to a better recognition result to our baseline instance segmentation model. Moreover, both geometric-only clustering and visual semantic information are combined to reduce the effect of segmentation error due to small-scale objects, occlusion and motion blur. Thorough experiments have been conducted to evaluate the performance of the proposed method. The results show that our method can precisely identify dynamic objects under recognition imperfection and motion blur. Moreover, the proposed SLAM framework is able to efficiently build a static dense map at a processing rate of more than 10 Hz, which can be implemented in many practical applications. Both training data and the proposed method is open sourced 1 .
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