Automotive Science and Engineering

Active Control of the Bounce and Roll of a Suspension System Using Optimal and Fuzzy ‎Approaches

Hami Tourajizadeh

Conventional suspension systems exhibit performance limitations when encountering road irregularities and specific surface profiles, often failing to attenuate road-induced disturbances effectively. This functional deficiency reduces ride comfort and compromises vehicle dynamic stability under various driving conditions. In contrast, active suspension systems, utilizing hydraulic or pneumatic actuators in combination with feedback control strategies, have demonstrated a significant potential for disturbance suppression and considerable improvement in ride comfort and vehicle stability. Previous studies have identified that vertical (bounce) and rotational (roll) motions are among the primary factors influencing passenger comfort and vehicle stability in dynamic scenarios. Therefore, controlling these motions is essential to enhance ride quality and handling performance. In this study, a half-car dynamic model equipped with an active suspension system is developed, focusing on controlling bounce and roll motions. All modeling and simulation tasks are conducted within the MATLAB environment, where two control strategies fuzzy control and optimal control are designed and implemented for the active suspension system. Finally, the dynamic performance of these two approaches is compared and analyzed. The simulation results indicate that the optimal control strategy outperforms the fuzzy control method regarding disturbance rejection and overall ride comfort and vehicle stability improvement.

RD-CFAR: Fast and Accurate Constant False Alarm Rate Algorithm for Automotive Radar Application

Jamal Kazazi

Target detection using cameras or automotive radar to identify traffic or prevent collisions is an important issue in Autonomous Vehicles (AV) research. Traditional Constant False Alarm Rate (CFAR) methods are commonly employed. Although these methods are suitable for lightweight hardware, improving the target detection process often leads to losing real-time performance. The method proposed in this paper improves detection accuracy. It reduces response time by modifying the position of guard cells in the first stage and employing harmonic averaging (inverse of the sum of the inverse of data) while eliminating data sorting in the second stage. Moreover, this approach exhibits better performance in the presence of interfering targets. Since the proposed method is more applicable to the Range-Doppler map, it has been named RD-CFAR. The proposed method also enhances target detection in Synthetic Aperture Radar (SAR) images. Simulation results demonstrate that the proposed algorithm improves detection probability by nearly 40% compared to conventional methods (like CA-CFAR), while maintaining comparable computational time.

Durability-Driven Energy Management for Fuel Cell Hybrid EVs: Multi-Scenario Optimization Across Different Traffic and Driving Cycles

Morteza Montazeri

The rising demand for sustainable transportation has intensified research on Fuel Cell Hybrid Electric Vehicles (FCHEVs). Integrating fuel cells with lithium-ion batteries provides a pathway to enhance energy efficiency and driving performance, but ensuring the durability of both components under real operating conditions remains a critical challenge. This work proposes an integrated framework to improve FCHEV performance and lifetime through combined modeling, degradation analysis, and optimized energy management. Dynamic vehicle simulations were conducted using the ADVISOR platform under both the Urban Dynamometer Driving Schedule (UDDS) and a real-world cycle based on Tehran traffic data. Degradation models were implemented to capture platinum dissolution in the Proton Exchange Membrane Fuel Cell (PEMFC) and capacity loss in the lithium-ion battery, incorporating the effects of state of charge, temperature, and current rate. An energy management strategy was developed using a Fuzzy Logic Controller (FLC) for fuel cell–battery power distribution, which was further refined with a Genetic Algorithm (GA). The optimization objectives included reducing hydrogen consumption and extending component lifetimes. The GA-optimized FLC extended PEMFC lifetime by 50.6% Tehran and 12.9% UDDS and reduced battery capacity fade by 10% and 4.9%, respectively. While direct hydrogen consumption increased in Tehran due to more aggressive regenerative-energy routing to the battery, the Equivalent Fuel Consumption (EFC) decreased from 971.32 → 937.21 g/100 km (Tehran) and 794.41 → 782.24 g/100 km (UDDS), reflecting a net efficiency gain once SOC restoration is accounted for.

Collision Avoidance in Cluttered Environments: A Low-cost Mechatronic Approach for Autonomous Robots

Mansour Hakim-Elahi

The deployment of autonomous robots in unstructured, cluttered environments remains a significant challenge, particularly for low-cost platforms. While the Dynamic Window Approach (DWA) provides a robust foundation for reactive navigation, its performance is often suboptimal due to a lack of historical context, leading to oscillatory behavior and entrapment in local minima. This paper presents a novel, cost-effective mechatronic system that enhances DWA with a real-time spatial memory module and optimizes its performance using a Bayesian Optimization strategy. Our platform integrates a Raspberry Pi 4 with a fused ultrasonic and infrared sensor suite. The core innovation is a Local Occupancy History Map that provides a short-term, decaying memory of obstacle locations. This memory influences the DWA’s trajectory evaluation, discouraging paths through recently occupied space. Furthermore, we employ Bayesian Optimization loop to automatically tune the critical hyperparameters of the navigation system—the memory decay rate and the history weight—to maximize efficiency and safety. We validate our system in complex indoor environments, comparing the baseline DWA, the DWA with Spatial Memory (DWA-SM), and the optimized DWA-SM (DWA-SM-Opt). Quantitative results demonstrate that the optimized system (DWA-SM-Opt) achieves a 40% reduction in average path completion time and a 65% decrease in collisions compared to the baseline DWA. Qualitative analysis confirms more intelligent, fluid navigation and a consistent ability to escape trapping configurations. This work establishes that the fusion of a lightweight spatial memory with an AI-driven optimization routine, implemented on low-cost hardware, can yield a level of performance previously associated with more complex and expensive systems.

Numerical and Experimental Analysis of the Vibration Response of Lithium-Ion Battery Packs

Abbas Rahi

This study investigates the dynamic response of a lithium‑ion battery pack subjected to environmental vibrations. Considering the widespread use of such packs in electric vehicles and energy storage systems, and the adverse effects of vibrations on their performance and safety, both numerical and experimental approaches are employed. In the numerical simulation phase, a detailed three-dimensional model of the battery pack, including all components and joints, is developed in Abaqus, and a full modal analysis is performed to extract the natural frequencies and mode shapes of the system. In the experimental phase, modal testing is conducted using an impact hammer and an accelerometer on a physical battery-pack sample under free‑free boundary conditions to validate the simulation results. A systematic comparison between the two approaches demonstrates a good agreement, with the maximum deviation in the primary natural frequencies being less than 10%. This level of consistency confirms the accuracy and reliability of the proposed model. The developed model can serve as an effective tool during the early design stages for mechanical optimization, dynamic behavior prediction, and mitigation of vibration‑induced failures in battery packs. The results of this study mark an important step toward improving the reliability and safety of battery packs in operational environments.

Comparison of the strength and energy absorption of adhesive-bonded with resistance spot-welded single-lap joints

javad marzbanrad

In lightweight body-in-white design, joints must not only provide strength but also allow for ductility and sufficient energy absorption. In this study, Single Lap Joints (SLJs) made with adhesive bonding are compared experimentally with those joined by Resistance Spot Welding (RSW) in low-carbon steel sheets. The influence of overlap length (15 and 25 mm) and weld number (one or two spots) is examined. Tensile force–displacement tests, conducted at room temperature with a crosshead speed of 1 mm/min, revealed that extending the overlap from 15 to 25 mm improved the peak load, final displacement, and fracture energy of the adhesive joints. Among the tested configurations, double spot welds (2RSW) provided the greatest capacity and toughness. However, adhesive joints with a 25 mm overlap (AB25) exhibited higher strength than single spot welds (1RSW), while their ductility was comparable. The observed failure modes varied across the joint types. In resistance spot welds, failure occurred mainly through button pull-out, whereas adhesive joints exhibited a mixed adhesive–cohesive failure mode. In contrast, the 2RSW specimens displayed pull-out and necking sequences, reflecting load sharing between the weld nuggets. Overall, the findings suggest straightforward design guidelines. When maximum strength and energy absorption are required, two Spot Welds (2RSW) are the best choice. On the other hand, AB25 joints, with a 25 mm overlap, provide higher strength than single Spot Welds (1RSW).