Browse Topic: Electronic braking systems
This study investigated the feasibility of using Deep Reinforcement Learning (DRL) for aeroelastic stability control of a Tiltrotor Aeroelastic Stability Testbed (TRAST) model. The DRL controllers use rotor swashplate inputs to minimize oscillatory wing root bending moments of the tilt rotor model. First, three DRL-based agents including Deep Deterministic Policy Gradient (DDPG), Twin Delayed Deep Deterministic Policy Gradient (TD3), and Soft Actor-Critic (SAC) were investigated to control the aeroelastic stability of the TRAST model throughout a wide range of airspeed including where the whirl flutter occurs. All three agents demonstrated the capability of stability augmentation while the SAC agent demon-strated the most robust performance. Next, the effectiveness of the SAC agent was studied further by training the SAC agent at a certain airspeed and applying the trained agent through the TRAST whirl flutter conditions. Finally, additional tuning of the SAC agent was performed to improve performance further through a hyperparameter optimization framework called Optuna.
With the growing trend of electric vehicles (EVs) incorporating regenerative braking systems, many compact SUVs, including hybrids and EVs, still utilize drum brakes on the rear wheels to strike a balance between cost, performance, and durability. Drum brake squeal remains a complex and persistent challenge in the field of vehicle noise, vibration, and harshness (NVH). This issue stems from dynamic instability caused by time–dependent friction forces. Traditional linear modal analysis has been used to study the mechanisms behind drum brake squeal, focusing on harmonic vibrations in large–scale models. However, these methods often fail to accurately correlate with real world behavior due to the presence of extra, non-physical modes. To address this, time–domain analysis approaches have been explored, incorporating detailed friction models and contact mechanics. These methods consider different root causes for high and low–frequency squeal and have shown promising results in accurately predicting brake squeal behavior when validated against experimental data.
This study presents an integrated vehicle dynamics framework combining a 12-degree-of-freedom full vehicle model with advanced control strategies to enhance both ride comfort and handling stability. Unlike simplified models, it incorporates linear and nonlinear tire characteristics to simulate real-world dynamic behavior with higher accuracy. An active roll control system using rear suspension actuators is developed to mitigate excessive body roll and yaw instability during cornering and maneuvers. A co-simulation environment is established by coupling MATLAB/Simulink-based control algorithms with high-fidelity multibody dynamics modeled in ADAMS Car, enabling precise, real-time interaction between control logic and vehicle response. The model is calibrated and validated against data from an instrumented test vehicle, ensuring practical relevance. Simulation results show significant reductions in roll angle, yaw rate deviation, and lateral acceleration, highlighting the effectiveness of the proposed approach. Overall, the framework offers a scalable and robust foundation for developing adaptive stability control systems in modern four-wheeled vehicles
As the brain and the core of the electric powertrain, the traction inverter is an essential part of electric vehicles (EVs). It controls the power conversion from DC to AC between the electric motor and the high-voltage battery to enable effective propulsion and regenerative braking. Strong and scalable inverter testing solutions are becoming more essential as EV adoption rises, particularly in developing nations like India. In India, traditional testing techniques that use actual batteries and e-motors present several difficulties, such as significant safety hazards, inadequate infrastructure, expensive battery prices, and a shortage of prototype-grade parts. This paper presents a comprehensive approach for traction inverter validation using the AVL Inverter TS™ system incorporating an advanced Power Hardware-in-the-Loop (PHiL) test system based on e-motor emulation technology. It enables safe, efficient, and reliable testing eradicating the need for actual batteries or mechanical loads. Testing across signal and power levels and the validation of both inverter hardware and software under real-world driving scenarios can be facilitated with proposed test system. Indian OEM challenges like reduction in battery development costs, ensuring high replication precision, and managing thermal and power instability in early-stage prototypes are primary focus areas for this test system. With the Inverter TS, various motor types (IM, EESM, PMSM), switching strategies, and SiC based 800V architectures with different control architectures can be emulated and validated, which can further be optimized for powertrain efficiency. Inverter efficiency maps can be derived and fast control strategy can be iterated which facilitates the the overall drivetrain optimization. This paper focus on how adopting such emulation test methodologies can help EV developers to overcome infrastructure gaps, reduce time-to-market, and enhance powertrain efficiency at a lower cost.
Conventional control of Brake-by-Wire (BBW) systems, including electro-hydraulic brake(EHB) and electro-mechanical brake(EMB), relys on pressure sensors, the errors of which usually resulted inaccurate braking force tracking bringing a lot of safety hazards, e.g., wheel locking and slipping. To address challenges of accurate braking force control under the circumstance of the system nonliearities (such as friction) and uncertainties (such as stiffness characteristics) for a sensorless BBW system, this paper proposes a unified Layer-by-Layer Progressive (LLP) control framework to enable fast and precise brake control. The work has been conducted with three new contributions in the three cascaded stages within the control framework: in the coarse compensation stage, a load-adaptive LuGre friction model is proposed to handle modellable nonlinearities; in the fine compensation stage, an Adaptive Extended Disturbance Observer (AEDO) is developed to estimate and compensate for parameter uncertainties and external disturbances; and in the fine control stage, a cascaded nonlinear controller is designed to suppress unmodeled dynamics and residual disturbances. Through real-vehicle experiments, the proposed LLP method has been validated under both pulse and gradual braking conditions for BBW systems (include EHB and EMB systems). Under pulse braking conditions, the proposed method yields maximum response errors of 1.2bar for the EHB system and 6.3% for the EMB system. Under gradual braking conditions, the steady-state errors are 0.7bar for EHB and 1.74% for EMB. These results empirically confirm the effectiveness and robustness of the proposed method.
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