Benchmarking Particle Filter Algorithms for Efficient Velodyne-Based Vehicle Localization

Keeping a vehicle well-localized within a prebuilt-map is at the core of any autonomous vehicle navigation system. In this work, we show that both standard SIR sampling and rejection-based optimal sampling are suitable for efficient (10 to 20 ms) real-time pose tracking without feature detection that is using raw point clouds from a 3D LiDAR. Motivated by the large amount of information captured by these sensors, we perform a systematic statistical analysis of how many points are actually required to reach an optimal ratio between efficiency and positioning accuracy. Furthermore, initialization from adverse conditions, e.g., poor GPS signal in urban canyons, we also identify the optimal particle filter settings required to ensure convergence. Our findings include that a decimation factor between 100 and 200 on incoming point clouds provides a large savings in computational cost with a negligible loss in localization accuracy for a VLP-16 scanner. Furthermore, an initial density of ∼2 particles/m 2 is required to achieve 100% convergence success for large-scale (∼100,000 m 2 ), outdoor global localization without any additional hint from GPS or magnetic field sensors. All implementations have been released as open-source software

MultiVehicle Simulator (MVSim): Lightweight dynamics simulator for multiagents and mobile robotics research

Development of applications related to closed-loop control requires either testing on the field or on a realistic simulator, with the latter being more convenient. To ease that need, this work introduces MVSim, a simulator for multiple vehicles or robots capable of running in real time dozens of agents in simple scenarios, or a handful of them in complex scenarios. MVSim employs realistic physics-grounded friction models for tire–ground interaction, and aims at accurate and GPU-accelerated simulation of most common modern sensors employed in mobile robotics and autonomous vehicle research, such as depth and RGB cameras, or 2D and 3D LiDAR scanners. All depth-related sensors are able to accurately measure distances to 3D models provided by the user to define custom world elements. Efficient simulation is achieved by means of focusing on ground vehicles, which allows the use of a simplified 2D physics engine for body collisions while solving wheel–ground interaction forces separately. The core parts of the system are written in C++ for maximum efficiency, while Python, ROS 1, and ROS 2 wrappers are also offered. A custom publish/subscribe protocol based on ZeroMQ (ZMQ) is defined to allow for multiprocess applications to access or modify a running simulation. This simulator enables and makes easier to do research and development on vehicular dynamics, autonomous navigation algorithms, and simultaneous localization and mapping (SLAM) methods. An experimental performance benchmarking is provided against other state-of-the-art simulators showing significant less CPU usage. The project source code is freely available online under the BSD 3-clause license in https://github.com/MRPT/mvsim

Cambios en los comportamientos de salud, salud mental y física entre los adultos mayores bajo severas restricciones de confinamiento durante la pandemia de COVID-19 en España

We used data from 3041 participants in four cohorts of community-dwelling individuals aged ≥65 years in Spain collected through a pre-pandemic face-to-face interview and a telephone interview conducted between weeks 7 to 15 after the beginning of the COVID-19 lockdown. On average, the confinement was not associated with a deterioration in lifestyle risk factors (smoking, alcohol intake, diet, or weight), except for a decreased physical activity and increased sedentary time, which reversed with the end of confinement. However, chronic pain worsened, and moderate declines in mental health, that did not seem to reverse after restrictions were lifted, were observed. Males, older adults with greater social isolation or greater feelings of loneliness, those with poorer housing conditions, as well as those with a higher prevalence of chronic morbidities were at increased risk of developing unhealthier lifestyles or mental health declines with confinement. On the other hand, previously having a greater adherence to the Mediterranean diet and doing more physical activity protected older adults from developing unhealthier lifestyles with confinement. If another lockdown were imposed during this or future pandemics, public health programs should specially address the needs of older individuals with male sex, greater social isolation, sub-optimal housing conditions, and chronic morbidities because of their greater vulnerability to the enacted movement restrictionsThe Seniors-ENRICA-2 study was supported by Instituto de Salud Carlos III (Spain), State Secretary of R+D+I and FEDER/FSE research grants PI16/609, PI18/287, and 19/319; CIBERESP (16/01); and Cátedra de Epidemiología y Control del Riesgo Cardiovascular at UAM (#820024). ELS was supported by a Juan de la Cierva Contract from the Ministy of Universities. DMG and MSP were supported by supported by a “Ramon y Cajal”contract. Edad con Salud was funded by the Seventh Framework Programme (grant number 223071-COURAGE Study); the Insti tuto de Salud Carlos III (grants number PS09/00295(JMH), PS09/01845 (JLA), PI12/01490 (JMH), PI13/00059 (JLA), PI16/00212 (JMH), PI16/00218 (MM), PI16/01073 (JLA)); the European Regional Development Fund (ERDF) “A Way to Build Europe” (grant numbers PI12/01490, PI13/00059, PI16/00212 and PI16/01073);and CIBERSAM. EL was supported by the Sara Borrell postdoctoral programme (CD18/00099) from the Instituto de Salud Carlos III and co-funded by the European Union (FEDER/FSE, “Investing in your future”). BO was supported by the Miguel Servet programme (reference CP20/00040), funded by Instituto de Salud Carlos III and co-funded by European Union (ERDF/ESF, "Investing in your future"). The Toledo Study for Healthy Ageing was funded by the Spanish Ministry of Economy, Industry and Competitiveness, cofinanced by FEDER (RD120001/0043), CIBERFES (CB16/10/00464) and DIABFRAIL-LATAM (contract number 825546, Horizon 2020). The Elderly EXERNET multicenter study was supported by the Ministerio de Economía, Industria y Competitividad (DEP2016-78309-R (GVR)), the Ministerio de Educación y Ciencia (Red EXERNET DEP2005-00046 JAC)), the High Council of Sports (Consejo Superior de Deportes) of the Ministe rio de Cultura y Deportes (09/UPB/19 (JAC) and 45/UPB/20 (JAC)), CIBERFES, the 4IE+ project (0499_4IE_PLUS_4_E (NG)) funded by the Interreg V-A España-Portugal (POCTEP) 2014-2020 pro gram, and FEDER funds from the European Union (CB16/10/00477 (IA)). The funding agencies had no role in study design, data collection and analysis, interpretation of results, manuscript preparation or the decision to submit this manuscript for publicatio