Lunar tubes, natural underground structures on the Moon formed by ancient volcanic activity, offer natural protection from extreme temperatures, radiation, and micro-meteorite impacts, making them prime candidates for future lunar bases. However, the exploration of lunar tubes requires a high degree of mobility. Given the Moon's gravity, which is approximately six times weaker than Earth's, efficient navigation across rugged terrains within these lava tubes is achievable through jumping. In this work, we present the design of subsystems for a miniature hexapod rover weighing 1 kg, which can walk, jump, and stow. The walking system consists of two subsystems: one for in-plane walking, employing four single-degree-of-freedom (DOF) legs utilizing the KLANN walking mechanism, and another for directional adjustments before jumping. The latter employs a novel three-DOF mechanism employing a cable pulley mechanism to optimize space utilization.
Continuous improvements and innovations towards sustainability in the aviation industry has brought interest in electrified aviation. Electric aircrafts have short missions in which the temporal variability of thermal loads are high. Lithium-ion (Li-ion) batteries have emerged as prominent power source candidate for electric aircrafts and Urban Air Mobility (UAM). UAMs and Electric aircrafts have large battery packs with battery capacity ranging in hundreds or thousands of kWh. If the battery is exposed to temperatures outside the optimum range, the life and the performance of the battery reduces drastically. Hence, it is crucial to have a Thermal Management System (TMS) which would reduce the heat load on battery in addition to cabin, and machinery thermal loads. Thermal management can be done through active or passive cooling. Adding a passive cooling system like Phase Change Material (PCM) to the TMS reduces the design maximum thermal loads.
In Intelligent Surveillance and Reconnaissance (ISR) missions, multiple autonomous vehicles, such as unmanned ground vehicles (UGVs) or unmanned aerial vehicles (UAVs), coordinate with each other for efficient information gathering. These vehicles are usually battery-powered and require periodic charging when deployed for continuous monitoring that spans multiple hours or days. In this paper, we consider a mobile host charging vehicle that carries distributed sources, such as a generator, solar PV and battery, and is deployed in the area where the UAVs and UGVs operate. However, due to uncertainties, the state of charge of UAV and UGV batteries, their arrival time at the charging location and charging duration cannot be predicted accurately.
Battery electric vehicles are quickly gaining momentum to improve vehicle fuel efficiency and emission reduction. However, they have to be designed to provide an adequate range on a single charge combined with good acceleration performance, top speed, grade and fast charging times. The paper presents a model for sizing the power train of an electric vehicle, including the power electronic converter, electric motor, and battery pack assuming an optimal wheel slip rate that modern vehicles can achieve using slip control systems. Simulations, using MATLAB/Simulink, were conducted based on speed and acceleration profiles. Additionally, the impact of wide-bandgap semiconductor devices and regenerative braking on the sizing process was studied. The research utilized a validated full nonlinear vehicle model that uses optimal value for the slip rate, considering the effect of the weather conditions, vehicle dynamics, road states, and traction/braking control systems.
In recent years, the burgeoning applications of hydrogen fuel cells have ignited a growing trend in their integration within the transportation sector, with a particular focus on their potential use in multi-rotor drones. The heightened mass-based energy density of fuel cells positions them as promising alternatives to current lithium battery-powered drones, especially as the demand for extended flight durations increases. This article undertakes a comprehensive exploration, comparing the performance of lithium batteries against air-cooled fuel cells, specifically within the context of multi-rotor drones with a 3.5kW power requirement. The study reveals that, for the specified power demand, air-cooled fuel cells outperform lithium batteries, establishing them as a more efficient solution.
The transportation sector's profound impact on greenhouse gas emissions mandates a paradigm shift towards eco-friendly solutions. School buses are one of the largest bus networks in the USA and are deployed in an ad hoc manner. These buses are widely running on fossil fuels which account for over five million tons of yearly greenhouse gas emissions and require the execution of a variety of steps to deploy a fleet of smart e-school busses. This study addresses the need by focusing on the transition from diesel-fueled to electric school buses (e-buses) to minimize environmental impact. However, e-buses face a critical challenge: their limited driving range compared to diesel counterparts. To tackle this issue, accurate predictive models for e-school bus electrical loads are essential for performance optimization. This research introduces a comprehensive control-oriented model for estimating auxiliary loads in electric school buses.
KEYWORDS – True implementation of Atkinson cycle, ICE cycles with extended expansion and continuous VCR variation, indicated fuel conversion efficiency, unlimited high pressure turbocharging, hydrogen and multi fuel operation, throttle-free new load control while maintaining a stoichiometric mixture Ultra-Downsizing (UD) was introduced as an even higher level of downsizing for Internal Combustion Engines ICEs, see SAE 2015-01-1252.
SAE EDGE Research Reports provide examinations significant topics facing mobility industry today including Connected Automated Vehicle Technologies Electrification Advanced Manufacturing
SAE EDGE Research Reports provide examinations significant topics facing mobility industry today including Connected Automated Vehicle Technologies Electrification Advanced Manufacturing
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