This work introduces a model predictive control (MPC) approach designed for tracking changing setpoints with implicit terminal components. In the presented method, an artificial setpoint is used as a decision variable...
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Bulk trailers are vehicles that are used for transporting powdered construction materials such as cement and fly ash. To ensure high transportation efficiency and low transportation costs, materials stored in the tank...
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In this paper, platoons of autonomous vehicles operating in urban road networks are considered. From a methodological point of view, the problem of interest consists of formally characterizing vehicle state trajectory...
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In this paper, platoons of autonomous vehicles operating in urban road networks are considered. From a methodological point of view, the problem of interest consists of formally characterizing vehicle state trajectory tubes by means of routing decisions complying with traffic congestion criteria. To this end, a novel distributed control architecture is conceived by taking advantage of two methodologies: deep reinforcement learning and model predictive control. On one hand, the routing decisions are obtained by using a distributed reinforcement learning algorithm that exploits available traffic data at each road junction. On the other hand, a bank of model predictive controllers is in charge of computing the more adequate control action for each involved vehicle. Such tasks are here combined into a single framework:the deep reinforcement learning output(action) is translated into a set-point to be tracked by the model predictive controller;conversely, the current vehicle position, resulting from the application of the control move, is exploited by the deep reinforcement learning unit for improving its reliability. The main novelty of the proposed solution lies in its hybrid nature: on one hand it fully exploits deep reinforcement learning capabilities for decisionmaking purposes;on the other hand, time-varying hard constraints are always satisfied during the dynamical platoon evolution imposed by the computed routing decisions. To efficiently evaluate the performance of the proposed control architecture, a co-design procedure, involving the SUMO and MATLAB platforms, is implemented so that complex operating environments can be used, and the information coming from road maps(links,junctions, obstacles, semaphores, etc.) and vehicle state trajectories can be shared and exchanged. Finally by considering as operating scenario a real entire city block and a platoon of eleven vehicles described by double-integrator models, several simulations have been performed with the a
This paper proposes a novel approach to VDM(vehicle dynamics model) determination problem for model-aided navigation of an AUV(autonomous underwater vehicle) when the DVL(doppler velocity log) is unavailable. The conv...
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Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected...
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Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impedance of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standard test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 K·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impedance, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.
Minimum quantity lubrication(MQL)is a relatively efficient and clean alternative to flooding workpiece *** atomization has the merits of small droplet diameter,high uniformity of droplet size,and strong coating,hence ...
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Minimum quantity lubrication(MQL)is a relatively efficient and clean alternative to flooding workpiece *** atomization has the merits of small droplet diameter,high uniformity of droplet size,and strong coating,hence its superiority to pneumatic ***,as the current research hotspot,the influence of jet parameters and electrical parameters on the average diameter of droplets is not ***,by observing the shape of the liquid film at the nozzle outlet,the influence law of air pressure and voltage on liquid film thickness(h)and transverse and longitudinal fluctuations are ***,the mathematical model of charged droplet volume average diameter(VAD)is constructed based on three dimensions of the liquid film,namely its thickness,transverse wavelength(λ_(h)),and longitudinal wavelength(λ_(z)).The model results under different working conditions are obtained by numerical *** of the model results with the experimental VAD of the droplet confirm the error of the mathematical model to be less than 10%.The droplet diameter distribution span value Rosin–Rammler distribution span(R.S)and percentage concentrations of PM10(particle size of less than 10μm)/PM2.5(particle size of less than 2.5μm)under different working conditions are further *** results show that electrostatic atomization not only reduces the diameter distribution span of atomized droplets but also significantly inhibits the formation of PM10 and PM2.5 fine-suspension *** the air pressure is 0.3 MPa,and the voltage is 40 kV,the percentage concentrations of PM10 and PM2.5 can be reduced by 80.72%and 92.05%,respectively,compared with that under the pure pneumatic atomization condition at 0.3 MPa.
Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and ***,the fabrication of hierarchical mi...
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Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and ***,the fabrication of hierarchical micro/nanograting structures is important for these *** this study,a strategy for machining hierarchical micro/nanograting structures is developed by controlling the tool movement trajectory.A coupling Euler-Lagrange finite element model is established to simulate the machining *** effect of the machining methods on the nanograting formation is demonstrated,and a suitable machining method for reducing the cutting force is *** height of the nanograting decreases with an increase in the tool edge ***,optical variable devices(OVDs)are machined using an array overlap machining *** schemes for the parallel column unit crossover and column unit in the groove crossover are designed to achieve high-quality machining of *** coloring of the logo of the Harbin Institute of Technology and the logo of the centennial anniversary of the Harbin Institute of Technology on the surface of metal samples,such as aluminum alloys,is *** findings of this study provide a method for the fabrication of hierarchical micro/nanograting structures that can be used to prepare OVDs.
The efficiency of water electrolysis is significantly affected by the bubbles on the surface and inside the *** enhance the gas-liquid transfer within the porous electrodes,we developed an innovative design termed dua...
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The efficiency of water electrolysis is significantly affected by the bubbles on the surface and inside the *** enhance the gas-liquid transfer within the porous electrodes,we developed an innovative design termed dual-aligned porous electrode(D-APE),achieved by integrating magnetic alignment with freeze casting *** paper investigates the hydrogen evolution performance of porous electrodes prepared using four different methods:evaporation,magnetic-aligned evaporation,freeze casting,and dual-aligned *** findings demonstrate that the magnetic-aligned process effectively alters the electrode structure,resulting in improved hydrogen evolution ***,among all the examined electrodes,the D-APE exhibits the highest hydrogen evolution performance,with further enhancements observed with prolonged the time of magnetic ***,a comparison is made between electrodes prepared using the freeze casting method and the dual-aligned method at various *** results show that the thinner D-APE exhibits excellent hydrogen evolution performance at high current ***,the D-APE demonstrates significantly improved material utilization rates compared to the conventional freeze casting method,offering promising prospects for enhancing the efficiency of water electrolysis.
As the application fields of Autonomous Mobile Robots (AMRs) expand, stress-free interaction with people around them becomes more important. AMRs are highly required to interact with pedestrians like human-human inter...
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