2,139 research outputs found

    Simultaneous Estimation of Vehicle Sideslip and Roll Angles Using an Event-Triggered-Based IoT Architecture

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    In recent years, there has been a significant integration of advanced technology into the automotive industry, aimed primarily at enhancing safety and ride comfort. While a notable proportion of these driver-assist systems focuses on skid prevention, insufficient attention has been paid to addressing other crucial scenarios, such as rollovers. The accurate estimation of slip and roll angles plays a vital role in ensuring vehicle control and safety, making these parameters essential, especially with the rise of modern technologies that incorporate networked communication and distributed computing. Furthermore, there exists a lag in the transmission of information between the various vehicle systems, including sensors, actuators, and controllers. This paper outlines the design of an IoT architecture that accurately estimates the sideslip angle and roll angle of a vehicle, while addressing network transmission delays with a networked control system and an event-triggered communication scheme. Experimental results are presented to validate the performance of the IoT architecture proposed. The event-triggered scheme of the IoT solution is used to decrease data transmission and prevent network overload.Funding. Grant [ PID2022-136468OB-I00 ] funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”

    Temperature Reduction Technologies Meet Asphalt Pavement: Green and Sustainability

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    This Special Issue, "Temperature Reduction Technologies Meet Asphalt Pavement: Green and Sustainability", covers various subjects related to advanced temperature reduction technologies in bituminous materials. It can help civil engineers and material scientists better identify underlying views for sustainable pavement constructions

    Traction Control Allocation Employing Vehicle Motion Feedback Controller for Four-wheel-independent-drive Vehicle

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    A novel vehicle traction algorithm solving the traction force allocation problem based on vehicle center point motion feedback controller is proposed in this paper. The center point motion feedback control system proposed utilizes individual wheel torque actuation assuming all wheels are individually driven. The approach presented is an alternative to the various direct optimization-based traction force/torque allocation schemes. The proposed system has many benefits, such as significant reduction of the algorithm complexity by merging most traction system functionalities into one. Such a system enables significant simplification, unification, and standardization of powertrain control design. Moreover, many signals needed by conventional traction force allocation methods are not required to be measured or estimated with the proposed approach, which are among others vehicle mass, wheel loading (normal force), and vehicle center of gravity location. Vehicle center point trajectory setpoints and measurements are transformed to each wheel, where the tracking is ensured using the wheel torque actuation. The proposed control architecture performance and analysis are shown using the nonlinear twin-track vehicle model implemented in Matlab &\& Simulink environment. The performance is then validated using high fidelity FEE CTU in Prague EFORCE formula model implemented in IPG CarMaker environment with selected test scenarios. Finally, the results of the proposed control allocation are compared to the state-of-the-art approach

    Optimal speed trajectory and energy management control for connected and automated vehicles

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    Connected and automated vehicles (CAVs) emerge as a promising solution to improve urban mobility, safety, energy efficiency, and passenger comfort with the development of communication technologies, such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I). This thesis proposes several control approaches for CAVs with electric powertrains, including hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs), with the main objective to improve energy efficiency by optimising vehicle speed trajectory and energy management system. By types of vehicle control, these methods can be categorised into three main scenarios, optimal energy management for a single CAV (single-vehicle), energy-optimal strategy for the vehicle following scenario (two-vehicle), and optimal autonomous intersection management for CAVs (multiple-vehicle). The first part of this thesis is devoted to the optimal energy management for a single automated series HEV with consideration of engine start-stop system (SSS) under battery charge sustaining operation. A heuristic hysteresis power threshold strategy (HPTS) is proposed to optimise the fuel economy of an HEV with SSS and extra penalty fuel for engine restarts. By a systematic tuning process, the overall control performance of HPTS can be fully optimised for different vehicle parameters and driving cycles. In the second part, two energy-optimal control strategies via a model predictive control (MPC) framework are proposed for the vehicle following problem. To forecast the behaviour of the preceding vehicle, a neural network predictor is utilised and incorporated into a nonlinear MPC method, of which the fuel and computational efficiencies are verified to be effective through comparisons of numerical examples between a practical adaptive cruise control strategy and an impractical optimal control method. A robust MPC (RMPC) via linear matrix inequality (LMI) is also utilised to deal with the uncertainties existing in V2V communication and modelling errors. By conservative relaxation and approximation, the RMPC problem is formulated as a convex semi-definite program, and the simulation results prove the robustness of the RMPC and the rapid computational efficiency resorting to the convex optimisation. The final part focuses on the centralised and decentralised control frameworks at signal-free intersections, where the energy consumption and the crossing time of a group of CAVs are minimised. Their crossing order and velocity trajectories are optimised by convex second-order cone programs in a hierarchical scheme subject to safety constraints. It is shown that the centralised strategy with consideration of turning manoeuvres is effective and outperforms a benchmark solution invoking the widely used first-in-first-out policy. On the other hand, the decentralised method is proposed to further improve computational efficiency and enhance the system robustness via a tube-based RMPC. The numerical examples of both frameworks highlight the importance of examining the trade-off between energy consumption and travel time, as small compromises in travel time could produce significant energy savings.Open Acces

    Implementation of Automatic DC Motor Braking PID Control System on (Disc Brakes)

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    The vital role of an automated braking system in ensuring the safety of motorized vehicles and their passengers cannot be overstated. It simplifies the braking process during driving, enhancing control and reducing the chances of accidents. This study is centered on the design of an automatic braking device for DC motors utilizing disc brakes. The instrument employed in this study was designed to accelerate the vehicle in two primary scenarios - before the collision with an obstacle and upon crossing the safety threshold. It achieves this by implementing the Proportional Integral Derivative (PID) control method. A significant part of this system comprises ultrasonic sensors, used for detecting the distance to obstructions, and rotary encoder sensors, which are utilized to measure the motor's rotational speed. These distance and speed readings serve as essential reference points for the braking process. The system is engineered to initiate braking when the distance value equals or falls below 60cm or when the speed surpasses 8000rpm. During such events, the disc brake is activated to reduce the motor's rotary motion. The suppression of the disc brake lever is executed pneumatically, informed by the sensor readings. Applying the PID method to the automatic braking system improved braking outcomes compared to a system without the PID method. This was proven by more effective braking results when the sensors detected specific distance and speed values. Numerous PID tuning tests achieved optimal results with K_p = 5, K_i = 1, and K_d = 3. These values can be integrated into automatic braking systems for improved performance. The PID method yielded more responsive braking outcomes when applied in distance testing. On the contrary, the braking results were largely unchanged in the absence of PID. Regarding speed testing, the PID method significantly improved the slowing down of the motor speed when it exceeded the maximum speed limit of 8000 rpm. This eliminates the possibility of sudden braking, thus maintaining the system within a safe threshold. The average time taken by the system to apply braking was 01.09 seconds, an indication of its quick responsiveness. This research is a valuable addition to control science, applying the PID control method to automatic DC motor braking. It provides valuable insights and concrete applications of PID control to complex mechatronic systems. It is also noteworthy for its development and optimization of suitable PID parameters to achieve responsive and stable braking. The study, therefore, offers a profound understanding of how PID control can be employed to manage braking systems on automatic DC motors, thereby advancing knowledge and application of control in control science and mechatronics

    The Mogadishu Effect: America\u27s Failure-Driven Foreign Policy

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    The October 1993 Battle of Mogadishu, commonly referred to as “Black Hawk Down,” transformed American foreign policy in its wake. One of the largest special operations missions in recent history, the failures in Somalia left not only the United States government and military in shock, but also the American people. After the nation’s most elite fighting forces suffered a nearly 50 percent casualty rate at the hands of Somali warlords during what many Americans thought was a humanitarian operation, Congress and the American people erupted in anger. Although the United States has continued to be seen as an overbearing global peacekeeping force in the thirty years since Somalia, the Battle of Mogadishu served as the turning point for a generational foreign policy shift that significantly limited future global intervention because of the overt publicization of battle’s aftermath in the media, domestic and international reactions, and a fear of repeating the same mistakes elsewhere. The first major American loss of life after the Cold War, the battle and the reaction that followed, known as the “Mogadishu effect,” forced President Clinton to rethink the United States’ role internationally. Clinton and his administration struggled to convince the American people that involvement overseas, especially global peacekeeping, was vital to international order after becoming the world’s sole superpower. Congressional hearings, presidential correspondence, government documents, poll results, and numerous media releases across Clinton’s presidency mark the distinct shift in American foreign policy that took place after Mogadishu. Although he inherited involvement in the United Nations mission in Somalia from George H.W. Bush, the failures in Somalia transformed Clinton’s humanitarian involvement in Haiti, Bosnia, and Rwanda, tarnishing the remainder of his presidency and shifting expectations of significant American involvement in international peacekeeping after the Cold War

    Development and evaluation of 4WSS electric-driven chassis for high-clearance sprayer

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    IntroductionThe high clearance sprayer with conventional steering mechanisms, as an intelligent spraying machine, is frequently stuck or broken in muddy fields due to the excessive torque load.MethodsA Four-Wheel Self-Steering (4WSS) electric-driven chassis with a smaller turning radius and better passability is developed to handle complex agricultural terrains. The 4WSS chassis is mainly composed of two custom-designed steering bridges and four in-wheel drive motors. It can achieve steering and driving forward simultaneously through coordinate differential speed control of drive motors, saving a set of dedicated servo steering systems and requiring less torque during steering compared to conventional structures. A kinematic model depicting the speed relationships between four wheels is established via geometric analysis, and a Speed Distribution Controller (SDC) is designed to accomplish locomotion objectives.ResultsExperimental results demonstrate the effectiveness of the new prototype 4WSS chassis system in tracking speed and steering angle. Compared to conventional agricultural chassis, the 4WSS chassis has a smaller turning radius of 2,877 mm. DiscussionThe 4WSS chassis exhibits superior performance in typical field conditions, including muddy terrain, deep gullies, and ridges

    Historical Burdens on Physics

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    When learning physics, one follows a track very similar to the historical path of the evolution of this science: one takes detours, overcomes superfluous obstacles and repeats mistakes, one learns inappropriate concepts and uses outdated methods. In the book, more than 200 articles present and analyze such obsolete concepts methods. All articles have the same structure: 1. subject, 2. deficiencies, 3. origin, 4. disposal. The articles had originally appeared as columns in various magazines. Accordingly, we had tried to write them in an easily understandable way

    A Changing Landscape:On Safety & Open Source in Automated and Connected Driving

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