Conventional Suspension Systems Research Articles

Numerical Study of Reinforced Aluminum Composites for Steering Knuckles in Last-Mile Electric Vehicles

The steering knuckle is a critical component of the suspension and steering drive systems of electric vehicles. The electrification of last-mile vehicles presents a challenge in terms of cost, driving range and compensation of battery weight. This work presents a numerical methodology to evaluate 60XX series aluminum metal matrix composites (AMMCs) with reinforcement ceramic particles for steering knuckle components in medium heavy-duty last-mile cargo vehicles. The use of AMMCs provides lightweight knuckles with sufficient strength, stiffness and safety conditions for electrical vehicle cargo configurations. The numerical study includes three aluminum alloys, two AMMC alloys and an Al 6061-T6 alloy as reference materials. The medium-duty heavy vehicle class < 12 t, such as electrical vehicle cargo configurations, is considered for the numerical study (class 1–4). The maximum von Mises stress for class 4 AMMC alloys exceeds 350 MPa, limited by fracture toughness. The weight reduction is about 65% when compared with commercial cast iron. Moreover, Al 6061-T6 alloys exhibit stress values surpassing 300 MPa, constraining their suitability for heavier vehicles. The study proposes assessing the feasibility of implementing AMMC alloys in critical components like steering knuckles and suggests solutions to enhance conventional vehicle suspension systems and overcome associated challenges. It aims to serve as a lightweight design guide, offering insights into stress variations with differing load conditions across various cargo vehicles.

Optimizing Hydro-Pneumatic Inerter Suspension for Improved Ride Comfort and Handling Stability in Engineering Vehicles Using Simulated Annealing Algorithm

This study introduces a novel hydro-pneumatic inerter suspension (HPIS) system for engineering vehicles, aiming at enhancing ride comfort and handling stability. The research focuses on addressing the limitations of conventional suspension systems by incorporating an inerter element into the vehicle suspension. The unique aspects of HPIS, such as nonlinear stiffness and nonlinear damping characteristics of the hydro-pneumatic spring, are explored. Firstly, a half-car dynamic model of the HPIS suspension is established, and an improved simulated annealing algorithm is applied to optimize the suspension parameters. Then, we compare the dynamic performance of different HPIS structures, specifically parallel and series layouts. For practical analysis, a simplified three-element HPIS suspension model is used, and the suspension parameters are optimized by a simulated annealing algorithm at speeds of 10 m/s, 15 m/s, and 20 m/s. Key findings reveal that compared to the traditional suspension system of S0, the front and rear suspension working space of S1 decreased by 40%, 40.1%, 40.2% and 30.7%, 30.8%, 30.9%, while with the body acceleration and pitch acceleration deteriorated by 3.1%, 3.2%, 3.3% and 63.4%, 63.8%, 64.0%. However, the S2 can improve all the dynamic performance and offer better ride comfort and handling stability.

Nanoconfined catalytic membrane assembled by nitrogen-doped carbon encapsulating Fe-based nanoparticles for rapid removal of 2,4-dichlorophenol in wastewater by peroxymonosulfate activation

Surface-dependent non-radical oxidation of carbon materials-based persulfate systems show a better application prospect in the removal of pollutants in complex wastewater. However, their potential is severely limited by the restricted liquid-to-solid mass transfer efficiency of conventional suspension systems. In this paper, a nitrogen-doped carbon encapsulating iron-based nanoparticles (Fe@NC) was prepared, and loaded onto a polyvinylidene fluoride (PVDF) membrane to construct a novel catalytic membrane Fe@NC/PVDF. The Fe@NC/PVDF/PMS system could achieve 99.74% of 2,4-dicholophenol (2,4-DCP) removal within a retention time of 0.867 s, the kinetic constant is 840 times higher than that of Fe@NC/PMS system, and 2–5 orders of magnitude higher than that of various reported advanced oxidation processes systems. The system exhibits strong anti-interference to various water matrices, long-time operational stability at high flux (306 L·m−2·h−1), universality to pollutants that do not contain strong electron-withdrawing groups and mitigation of membrane fouling. Mechanism studies indicate that the electron transfer pathway dominates the 2,4-DCP removal, and singlet oxygen (1O2) plays an auxiliary role. The higher mass transfer efficiency of the filtration mode releases the full potential of the non-radical pathway. This paper provides theoretical and technical support for the development and efficient utilization of carbon-based materials with excellent persulfate catalytic properties.

Utilizing Dynamic Analysis in the Complex Design of an Unconventional Three-Wheeled Vehicle with Enhancing Cornering Safety

Current trends in the transportation industry prioritize competitive rivalry, compelling manufacturers to prioritize concepts such as quality and reliability. These concepts are closely associated with public expectations of safety, vehicle lifespan, and trouble-free operation. However, the public must recognize that a vehicle weighing several hundred kilograms, moving at a non-zero speed, only contacts the road surface through a few points (depending on the number of wheels), each no larger than a human palm. Therefore, it is imperative to operate the vehicle in a manner that optimizes the behavior of these contact points. There are situations where drivers find themselves requiring dynamic vehicle handling, often unpredictable with a high degree of uncertainty. Rapid changes in direction become necessary in these cases. Such maneuvers can pose a significant risk of rollover for three-wheeled vehicles. Hence, the vehicle itself should contribute to increased ride safety. This paper presents key findings from the development of an unconventional three-wheeled vehicle utilizing the delta arrangement. Rollover safety for three-wheeled vehicles is currently well-managed, thanks to the utilization of electronic or mechatronic systems in delta-type vehicles to enhance stability. However, these systems require additional components. In contrast, the proposed control system operates solely on a mechanical principle, eliminating operational costs, energy consumption, maintenance expenses, and similar factors. The study also explores the absence of equivalent suspension and steering systems for front-wheel steering. Such designs are lacking in both practical applications and theoretical realms. Analytical and simulation calculations are compared in this study, highlighting the effectiveness of the newly proposed control system in enhancing stability and safety compared to conventional front-wheel suspension systems. Simulation programs provide more realistic results than analytical calculations due to their ability to account for dynamic effects on vehicle components and passengers, which is practically unfeasible in analytical approaches. Furthermore, this study focuses on investigating the fatigue life of material frames subjected to dynamic loading, which is a crucial aspect of ensuring safety. It is essential to have various testing devices to examine the fatigue life of materials under both uniaxial and multiaxial loading conditions. However, obtaining experimental results for fatigue life measurements of specific materials, which can be directly applied to one’s research, poses significant challenges. Hence, the proposed testing device plays a vital role in measuring material fatigue life and advancing the development of unconventional transportation methods. The information about the original testing device aligns perfectly with the article’s emphasis on dynamic analysis. The ultimate objective of all these efforts is to put the vehicle into practical operation for commercial utilization.

Model-Based Estimation of Vehicle Center of Gravity Height and Load

AbstractWith an increasing number of driver assistance functions and the upcoming trend of autonomous driving, knowledge of the current state and changeable parameters of the vehicle becomes more and more important. One particularly significant parameter with regard to vehicle dynamics is the center of gravity (COG) height, which mainly accounts for its roll dynamics in combination with the mass of the vehicle. Thus, a highly increased vehicle mass and COG height might lead to rollover during cornering, which underlines the need for accurate knowledge of the load of the vehicle. Based on that, an improved rollover prevention could be implemented, for instance, by enhancing the electronic stability program (ESP) of the vehicle. Therefore, the main contribution of this work is the model-based online estimation of the additional load of the vehicle, comprising its COG position and mass. This is achieved by applying a joint extended Kalman Filter (EKF) for the simultaneous state and parameter estimation. Based on a nonlinear model with roll, pitch, and vertical dynamics, an accurate and reliable estimation is possible. One major novelty of this work is the consideration of air suspension systems on top of conventional steel spring suspension systems. Therefore, a nonlinear air spring model with sufficient complexity is proposed, making it suitable for real-time applications. Further, a system theoretical observability analysis allows for an online adaptation of the Kalman Filter weights in order to account for different driving situations. The proposed estimation method is tested and validated by considering a wide range of driving situations, considering distinct loading conditions on both a test track and public roads. The estimation accuracy lies within roughly 50 kg and 1.5 cm for the vehicle mass and COG height, respectively.

Suspension Control Strategies Using Switched Soft Actor-Critic Models for Real Roads

In this article, we propose learning and control strategies for a semiactive suspension system in a full car using soft actor-critic (SAC) models on real roads, where many road profiles with various power of disturbance exist (e.g., speed bumps and general roads). Therefore, a technique that enables deep reinforcement learning to cover different domains with largely different reward functions is proposed. This concept was first realized in a simulation environment. Our proposed switching learning system continuously identifies two different road disturbance profiles in real time such that the appropriately designed SAC model can be learned and applied accordingly. The results of the proposed switching SAC algorithm were compared against those of advanced and conventional benchmark suspension systems. Based on the results, the proposed algorithm showed smaller root-mean-square values of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$z$</tex-math></inline-formula> -directional acceleration and pitch at the center of the body mass. Finally, we also presented our successfully implemented SAC training system in a real car on real roads. The trained SAC model outperforms conventional controllers reducing the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$z$</tex-math></inline-formula> -directional acceleration and pitch, similar to the simulation results, which is highly related to the riding comfort and vehicle maneuverability.

Power-efficient low-stray field hybrid magnets for MAGLEV technology

A hybrid suspension system is proposed for maglev transport that utilizes electromagnets (EM) in combination with permanent magnets (PM). Several design schemes are compared searching for optimum performance. Sufficient reduction of power consumption and stray field is achieved on the hybrid configuration as compared to conventional EM suspension systems.

Design of the Active Control Algorithm to Reduction of the Vibrations due to Interaction High-Speed Railway Vehicle Bogie and Structure

This study analyzes excessive vibrations that occurred on the railway vehicle bogie with the computer simulation of a 4-DOF half car railway bogie dynamic physical model and Euler-Bernoulli flexible bridge beam with the simply supported boundary conditions has been introduced considering some limitations which affect problem formulation. To reduce these excessive vibrations other than conventional suspension systems such as passive one, an active suspension system has been designed and attached to the primary suspension system of the railway bogie car. Then, to control these active suspension systems, a control algorithm based on PID and SMC is considered. The coupled equation of motion of the railway bogie car and flexible Euler-Bernoulli bridge beam is obtained by Hamilton’s principle in the time domain with the active suspension system. Finally, to demonstrate the effect of the active suspension system with the PID and SMC algorithm upon these excessive vibrations, a computer simulation has been implemented, and the results are presented comparatively. Consequently, the maximum railway vehicle bogie vertical displacement and vertical acceleration have been significantly reduced.

Structural and magnetic analysis of electro-magnetic suspension spring

Suspension is the term given to the arrangement of springs, shock absorbers and linkages that interfaces a vehicle to its wheels. Unlike conventional suspension systems that smother the vibrations by scattering the vibration energy into waste heat, the regenerative suspension with vitality reaping shock absorbers can change over the generally squandered vitality into electricity. Thus in this work, designing of the suspension spring for Hero Splendor Plus bike by applying Nimonic 80A material. Specifically, it focuses on a static and dynamic study of the suspension spring. This framework uses electromagnets as inactive dampers, which is utilized to lessen displacement and acceleration of spring mass so as to enhance drive ease.

Active hybrid suspension system: A review

In the current research paper, researcher has tried to give a review on hybrid/active suspension system. The primary purpose of a suspension system in an automobile is to sustain vehicle’s stability and maneuverability during irregular and uneven road surfaces. Owing to the fast changing technology, conventional suspension systems limit the performance necessary. However, the modern suspension systems lack the practicality of implementation. The objective of this research is to highlight the various damping systems available and thereby, taking into account the best feasible option for further research in the area. An attempt has been made by the researcher to review significant papers in this area and focus on considered parameters like performance, feasibility, capacity, safety etc.

Self-powered magnetorheological dampers for motorcycle suspensions

Dampers are the parts of suspensions which improve the ride comfort and the safety of vehicles including motorcycles. Magnetorheological dampers are very attractive for motorcycle suspensions, because of their controllable properties and their fast responses. Considerable energy is wasted owing to the energy dissipation by dampers encountering road irregularities and accelerating processes during everyday use of motorcycles. In addition, the current magnetorheological suspension systems depend on the power supply of batteries. Therefore, in this paper, a self-powered magnetorheological damper for motorcycle suspensions is proposed and implemented for the first time. It can convert the wasted mechanical energy into useful electrical energy to power itself. There are great merits in this such as energy saving, independence of extra batteries and less maintenance in comparison with conventional magnetorheological suspension systems, while keeping controllable performances. A customized prototype of the self-powered magnetorheological damper that is compatible with a motorcycle is developed and actually implemented in a motorcycle. Modelling for the self-powered magnetorheological damper is developed and validated by laboratory testing. Laboratory testing showed that the self-powered feature works well to generate the electrical power and to vary the magnetorheological damping force. Preliminary system-level testing showed that a self-powered magnetorheological suspension results in a better ride comfort, compared with that of a magnetorheological suspension without power generation. The results showed that implementing self-powered magnetorheological dampers in motorcycle suspensions is feasible and beneficial.

Adaptive soft computing paradigm for a full-car active suspension system with driver biodynamic vibration damping control

In the current car automobile industry, vehicle ride comfort is the most important design aspect due to its direct effect on the health and efficiency of human beings. The available literature on vehicle active suspension systems to improve vehicle performance (ride comfort, handling, road holding and suspension deflection, etc.) is somewhat sparse, and there is a major lack of research on seated driver biodynamic comfort analysis and enhancement. In this paper, a nonlinear full-car active suspension system with seated driver biodynamics [19 degrees of freedom (DoF)] model is presented. The effects of biodynamic vibrations on different parts of the driver’s body are examined. A NeuroFuzzy adaptive control paradigm is applied to the full-car active suspension system to damp the vehicle low-frequency vibrations, which can cause health problems and fatigue, resulting in fatal accidents. The effectiveness of the proposed control strategy to damp vehicle low-frequency and biodynamic vibrations is validated by comparing the performance with conventional (passive) and PID-controlled suspension systems.

Dynamic Behaviour of a 7 DoF Passenger Car Model

Conventional vehicle suspension systems, which are passive in nature consists of springs with constant stiffness and dampers with constant damping coefficient. These suspension systems cannot meet the characteristics such as ride comfort, road handing and suspension deflection during abnormal road conditions simultaneously. Active and semi-active suspension systems are the solutions to achieve the desired suspension characteristics. Since, active system is bulky and requires high energy for working, a semi-active suspension system is considered in the present work to analyze vehicle traversing over various road profiles for ride comfort. Mathematical model of a 7 DoF passenger car is formulated using Newton’s method. A semi-active suspension system with skyhook linear control strategy avoids the road excitations at resonant frequencies by shifting the natural frequencies of the model by varying damping coefficients based on the vehicle response for different road conditions where the excitations could be harmonic, transient and random. Modal analysis is carried out to identify the un-damped natural frequencies and mode shapes for different values of damping. The above analyses are carried out through analytical and numerical methods using MATLAB and ANSYS software respectively and the results obtained from both are in good agreement.

Particulate Photocatalyst Sheets Based on Carbon Conductor Layer for Efficient Z-Scheme Pure-Water Splitting at Ambient Pressure.

Development of sunlight-driven water splitting systems with high efficiency, scalability, and cost-competitiveness is a central issue for mass production of solar hydrogen as a renewable and storable energy carrier. Photocatalyst sheets comprising a particulate hydrogen evolution photocatalyst (HEP) and an oxygen evolution photocatalyst (OEP) embedded in a conductive thin film can realize efficient and scalable solar hydrogen production using Z-scheme water splitting. However, the use of expensive precious metal thin films that also promote reverse reactions is a major obstacle to developing a cost-effective process at ambient pressure. In this study, we present a standalone particulate photocatalyst sheet based on an earth-abundant, relatively inert, and conductive carbon film for efficient Z-scheme water splitting at ambient pressure. A SrTiO3:La,Rh/C/BiVO4:Mo sheet is shown to achieve unassisted pure-water (pH 6.8) splitting with a solar-to-hydrogen energy conversion efficiency (STH) of 1.2% at 331 K and 10 kPa, while retaining 80% of this efficiency at 91 kPa. The STH value of 1.0% is the highest among Z-scheme pure water splitting operating at ambient pressure. The working mechanism of the photocatalyst sheet is discussed on the basis of band diagram simulation. In addition, the photocatalyst sheet split pure water more efficiently than conventional powder suspension systems and photoelectrochemical parallel cells because H+ and OH- concentration overpotentials and an IR drop between the HEP and OEP were effectively suppressed. The proposed carbon-based photocatalyst sheet, which can be used at ambient pressure, is an important alternative to (photo)electrochemical systems for practical solar hydrogen production.

Particulate photocatalyst sheets for Z-scheme water splitting: advantages over powder suspension and photoelectrochemical systems and future challenges.

Water splitting using semiconductor photocatalysts has been attracting growing interest as a means of solar energy based conversion of water to hydrogen, a clean and renewable fuel. Z-scheme photocatalytic water splitting based on the two-step excitation of an oxygen evolution photocatalyst (OEP) and a hydrogen evolution photocatalyst (HEP) is a promising approach toward the utilisation of visible light. In particular, a photocatalyst sheet system consisting of HEP and OEP particles embedded in a conductive layer has been recently proposed as a new means of obtaining efficient and scalable redox mediator-free Z-scheme solar water splitting. In this paper, we discuss the advantages and disadvantages of the photocatalyst sheet approach compared to conventional photocatalyst powder suspension and photoelectrochemical systems through an examination of the water splitting activity of Z-scheme systems based on SrTiO3:La,Rh as the HEP and BiVO4:Mo as the OEP. This photocatalyst sheet was found to split pure water much more efficiently than the powder suspension and photoelectrochemical systems, because the underlying metal layer efficiently transfers electrons from the OEP to the HEP. The photocatalyst sheet also outperformed a photoelectrochemical parallel cell during pure water splitting. The effects of H+/OH- concentration overpotentials and of the IR drop are reduced in the case of the photocatalyst sheet compared to photoelectrochemical systems, because the HEP and OEP are situated in close proximity to one another. Therefore, the photocatalyst sheet design is well-suited to efficient large-scale applications. Nevertheless, it is also noted that the photocatalytic activity of these sheets drops markedly with increasing background pressure because of reverse reactions involving molecular oxygen under illumination as well as delays in gas bubble desorption. It is shown that appropriate surface modifications allow the photocatalyst sheet to maintain its water splitting activity at elevated pressure. Accordingly, we conclude that the photocatalyst sheet system is a viable option for the realisation of efficient solar fuel production.

Analysis and optimization of air suspension system with independent height and stiffness tuning

Suspensions play a crucial role in vehicle comfort and handling. Different types of suspensions have been proposed to address essential comfort and handling requirements of vehicles. The conventional air suspension systems use a single flexible rubber airbag to transfer the chassis load to the wheels. In this type of air suspensions, the chassis height can be controlled by further inflating the airbag; however, the suspension stiffness is not controllable, and it depends on the airbag volume and chassis load. A recent development in a new air suspension includes two air chambers (rubber airbags), allowing independent ride height and stiffness tuning. In this air suspension system, stiffness and ride height of the vehicle can be simultaneously altered for different driving conditions by controlling the air pressure in the two air chambers. This allows the vehicle’s natural frequency and height to be adjusted according to the load and road conditions. This article discusses optimization of an air suspension design with ride height and stiffness tuning. An analytical formulation is developed to yield the optimum design of the new air suspension system. Experimental results verify the mathematical modeling and show the advantages of the new air suspension system.

English

The suspension system plays a major role in any automobile as far as the vehicle stability and ride comfort of the passengers are considered. In conventional or passive suspension systems performance parameters like ride comfort, road holding and suspension travel, are mutually contradicting while active suspension system has the potential to improve these factors. The present work aims to study a full vehicle model having passive and active suspension system subjected to random road profile as per ISO standards. The linear quadratic controller (LQR) is used for active suspension system. Using optimization procedure the actuator force, which minimizes the performance index is determined. Passenger ride comfort is directly related to the passenger seat acceleration and road holding relates to wheel displacement and suspension travel. The active suspension system performance is compared with passive suspension system subjected to random road profile. Results show passenger bounce and acceleration are reduced drastically in active suspension system indicating improvement in both road holding and comfort.

Optimum design analysis of hybrid cable-stayed suspension bridges

A design methodology to predict optimum post-tensioning forces and dimensioning of the cable system for hybrid cable-stayed suspension (HCS) bridges is proposed. The structural model is based on the combination of an FE approach and an iterative optimization procedure. The former is able to provide a refined description of the bridge structure, which takes into account geometric nonlinearities involved in the bridge components. The latter is utilized to optimize the shape of post-tensioning forces as well as the geometry of the cable system to achieve minimum deflections, lowest steel quantity involved in the cable system and maximum performance of the cables under live load configurations. Results are proposed in terms of comparisons with existing formulations to validate the proposed methodology. Moreover, parametric studies on more complex long span structures are also developed to verify existing cable-dimensioning rules and to analyze between HCS bridges and conventional cable-stayed or suspension systems.

Characteristic analysis of pitch-resistant hydraulically interconnected suspensions for two-axle vehicles

This paper proposes a new method to investigate the characteristics of pitch-resistant hydraulically interconnected suspension (HIS) systems for two-axle vehicles in the pitch plane. The equations of motion for the mechanical and hydraulic coupled system are developed, in which the hydraulic strut forces are derived using the impedance transfer matrix method. The stiffness and damping matrices of the coupled systems are described in a manner similar to the generalized form of uncoupled conventional suspension (UCS) systems. The additional properties of HIS systems are explicitly described via hydraulic physical parameters. Based on the generalized form, (1) the accumulators of HIS systems can be functionally equivalent to a combined system with tandem bump and pitch-angular springs; (2) the direction damper valves (DDVs), which are located at the outlets of actuator cylinders, function like uncoupled tandem dampers; (3) the pitch damper valves (PDVs), which are fitted on the hose to connect the accumulators, alter the mode damping similar to the accumulators changing the mode stiffness; (4) the opposite installation corresponding to the schematic of front piston-rod-upward and rear piston-rod-downward produces higher mode stiffness and damping than the other installations. The dynamic responses are studied between the vehicles with HIS and UCS. Moreover, the damping coefficients are evaluated with the modal analysis method. The obtained results indicate that (1) the top and bottom DDVs mainly affect the vehicle body’s pitch motion and bounce vibration, respectively, (2) the PDVs are able to alter the load distribution among wheel stations, and (3) damping parameters can be designed to minimize the vehicle body’s pitch motion.

Optimization of suspension system of off-road vehicle for vehicle performance improvement

Vehicle suspension design includes a number of compromises to provide good leveling of stability and ride comfort. Optimization of off­road vehicle suspension system is one of the most effective methods, which could considerably enhance the vehicle stability and controllability. In this work, a comprehensive optimization of an off­read vehicle suspension system model was carried out using software ADAMS. The geometric parameters of suspension system were optimized using genetic algorithm (GA) in a way that ride comfort, handling and stability of vehicle were improved. The results of optimized suspension system and variations of geometric parameters due to road roughness and different steering angles were presented in ADAMS and the results of optimized and conventional suspension systems during various driving maneuvers were compared. The simulation results indicate that the camber angle variations decrease by the optimized suspension system, resulting in improved handling and ride comfort characteristics.