Suspension Damping Research Articles

Topology optimization with the redesigned suspension system of the internal combustion vehicle converted to an electrical vehicle

Abstract In this paper, the topology optimization of lower wishbone for a passenger car which is the converted of an internal combustion engine vehicle to an electrical vehicle was presented. On the other hand, the need to study on a suspension system arose for electrical car that was redesigned. In study, topology optimization of the structural design of the lower wishbone to be used in the front suspension was carried out by Finite Element Analysis (FEA) Method. For this purpose, firstly, the suspension spring curves and damper curves that will improve the handling, ride and comfort behaviour of the vehicle were determined, suspension system was modelled with the Multi Body Dynamics (MBD) approach. Hardpoints is necessary for vehicle dynamics and that is also an input for FEA were obtained from new suspension system via MBD analysis. In the second step, The preliminary design of the lower wishbone was created, taking into account together with the positions of the wheel drive shaft, suspension spring and brake system structural elements according to hardpoints. After designing the structure suitable for the joint types, initial design was studied on the remaining region that is for weight reduction region except the joint connection surfaces. Then, topology optimization was applied to the preliminary design for the selected load types that is come from MBD analysis. Thus, the excess volume on the preliminary design was determined for each load type. In the last stage, the results of topology optimization analysis were evaluated to reach out target weight and the producible design of the wishbone was made. Finally, Finite Element Analysis were applied to the final design for validation purposes within topology optimization work was done with the forces coming from Multi Body Dynamics. After statically solved Finite Element Analysis, a modal neutral file(.mnf) was created via FEA solver and was integrated to Adams Car as a flexbody. Flexbody was attahced to the other parts which are rigid bodies like nuckle according to Multi Body Dynamics approach. Dynamics durability cases was carried out via Adams Car. Stress results was compared to FEA results and evaluated depends on yield stress. Study results shows that the new design is lighter and competitive design and also safe in dynamics analysis for redesigned passenger car.

Technical study of magnetorheological semi-active suspension control strategy for vehicles based on reinforcement learning

The suspension system is an important part of the car, the main function is to alleviate the road surface does not level brought about by the shake, to ensure that the vehicle driving smoothness and comfort, so as to improve the vehicle handling performance and safety, improve the vehicle to reduce the vibration performance more and more become a hot topic in the industry. Among them, semi-active suspension is a popular suspension system. This paper explains the significance and classification of the role of the suspension, and gives a relevant introduction to the magnetorheological fluid, on the basis of which it combines the domestic and international research results, looks forward to the development trend of the semi-active suspension of the vehicle, analyzes the advantages and shortcomings of four important semi-active suspension control strategies, and finally introduces the reinforcement learning and combines the reinforcement learning with the existing control strategies of the semi-active suspension, and designs a reliable reward function to enhance the suspension's damping performance by taking into account the multifaceted driving factors. The reward function to enhance the damping ability of the suspension by considering multiple driving factors, which can provide a reference for further research on the control of magnetorheological semi-active suspensions for vehicles.

Influence of pneumatic tire enveloping behavior characteristics on the performance of a half car suspension system using multi-objective optimization algorithms

The interaction between a vehicle's tire and the road surface is pivotal for a driver's control over the vehicle's movements. It serves as the fundamental link between the vehicle and the road. The modeling of tires holds significant importance in contemporary vehicle design, playing a critical role in assessing aspects such as vehicle handling, ride comfort, and road load analysis. This study focuses on investigating the impact of the enveloping behavior characteristics of a pneumatic tire on the performance of a suspension system. The analysis of the vehicle's ride comfort utilizes a half-car model. Unlike a previous model with a single point of contact with the road, the presented suspension system, coupled with a four-degree-of-freedom rigid ring tire model, offers a more precise estimation of both ride comfort and road holding. The primary emphasis of this research lies in the modeling and evaluation of the proposed suspension system's performance. A comprehensive computer model of the entire system is developed using MATLAB software. This work enhances the existing framework by incorporating both a Multi-Objective Genetic Algorithm (MOGA) and a Multi-Objective Particle Swarm Optimization (MOPSO) to optimize the damping and stiffness coefficients of the passive suspension. This approach allows for a detailed comparison of the optimization capabilities and effectiveness of both algorithms in refining vehicle ride comfort. The results from MATLAB simulations highlight performance improvements, and the comparative analysis of MOGA and MOPSO provides insights into the selection of optimization techniques for suspension system design.

Optimal Layout of Suspension System Employing Mechatronic Inerter for Comfort Enhancement Based on Structure-Immittance Approach

<div>The usage of the inerter and its studies has greatly developed in recent years as it offers better performance compared to passive systems and has lower cost and power consumption than active and semi-active systems. This article focuses on studying a half-vehicle model to obtain the optimal layout of the mechatronic inerter, spring, and damper suspension system (ISD) for comfort enhancement with the aid of the structure-immittance approach, ensuring structural simplicity.</div> <div>The mechatronic inerter, which consists of a single capacitance, resistance, and inductance, is added to a half-vehicle model composed of an inerter, spring, and damper. All possible layouts are studied to achieve the optimal design layout. Evaluation criteria such as the performance index, system peak-to-peak value, and settling time are utilized to assess body acceleration, thereby improving passenger comfort. Furthermore, the system’s impact on dynamic tire load and suspension working space under diverse road conditions is analyzed. Theoretical analyses conducted using MATLAB/Simulink demonstrate that the novel mechatronic ISD layout significantly enhances body acceleration performance compared to conventional passive systems, switchable hydraulic ISD systems, and fuzzy logic-controlled three-setting switchable dampers.</div>

Modelling and Experimental Study of a Passive Frequency-Dependent Vehicle Suspension Damper

Abstract The recent trends in the automotive industry have enforced chassis solutions beyond the reach of conventional systems. Thus, extending the functionality of passive hydraulic dampers is vital in improving their effectiveness while maintaining low production and operating costs. This paper presents a general structure of a passive shock absorber with so-called frequency-dependent (FD) damping characteristics and points to constitutive elements of the valves used in this type of an adaptive damper. A mathematical description of FD damper is provided together with a model developed in the Siemens AMESim environment. The performance of the model was verified against the data from tests with a real, commercially available FD shock absorber. Furthermore, in order to emphasise its efficiency, the authors have carried out a study involving quarter car models (QCM) with and without the FD damper, respectively. The results have clearly shown major advantages of utilising FD dampers in a suspension.

Vertical dynamics analysis and multi-objective optimization of electric vehicle considering the integrated powertrain system

Integrated powertrain system, mainly composed of driving motor and reducer, is one of the excitation sources to electric vehicle vibration but is limited in coupling with the vertical vehicle dynamic in the existing research, which restricts the reliability of dynamics investigation of vehicle and integrated powertrain system. This work proposes a novel vertical dynamic model of the electric vehicle considering the integrated powertrain system, enabling the way to access the coupled vibration among the chassis, unsprung mass, and integrated powertrain system. The road irregularity, unbalanced magnetic pull, and gear mesh excitation are developed and are further applied to the novel vehicle dynamic model with ten degrees of freedom (DOFs). Then, the dynamic response between the novel model and traditional one is compared. Further, the effects of the stiffness and damping of suspension and mounting on the vibration of chassis and integrated powertrain system are explored by numerical calculation. Finally, a multi-objective optimization model is proposed and is driven by the dragonfly algorithm to minimize the vibration of chassis and integrated powertrain system. The research results shown that there will be present the new complex dynamic characteristics with considering the excitation from the integrated powertrain system. The suspension and mounting parameters have the nonlinear effects on the vehicle vibration. And the system vibration can be globally optimized with the optimization algorithm.

The nexus of sustainability and damping: A quasi-zero stiffness and pseudo-piecewise inerter damper for vehicle suspension

This paper proposes a vibration control-energy harvesting damper (VCEHD) for vehicle suspension. The principles used in the proposed VCEHD include quasi-zero stiffness (QZS), mechanical motion rectifier (MMR), and semi-active control. In the dynamic analysis, the authors found that the inherent disengagement and engagement properties of the MMR can undermine the robustness of the system, that is, the inherent properties of the MMR as an energy harvesting device are not conducive to vibration isolation. Therefore, it needs to be restrained. According to the numerical simulation results, VCEHD cannot simultaneously achieve the minimum body displacement and the maximum energy harvest, and the energy harvest performance needs to be partially sacrificed. The experimental results show that the maximum energy output is 14.70 mW/kg, and the minimum displacement transmissibility is 24.32%. Combined with the numerical simulation results, VCEHD can harvest 8.82–97.79 W of power in actual vehicle running, which can provide auxiliary power for intelligent vehicles.

Design and optimization of H-type asymmetric magnetic suspension vibration absorber for ships

The active–passive hybrid vibration isolation technology emerges with the advancement of the requirements for ship vibration and noise reduction. Among these, the magnetic suspension damper based on magnetic suspension technology has received more attention. In this paper, the effects of magnetic pole area and control current on the magnetic flux density and suspension force are verified by establishing a magnetic suspension structure model and comparing and verifying the results carried out by combining the theoretical formulas and finite element simulation. By exploring the effect of the structure on the magnetic flux density and suspension force, a new H-type asymmetric magnetic suspension structure is proposed and simulated. The results show that the H-type asymmetric magnetic suspension structure is more successful at improving the suspension force while also widening the suspension force response interval and improving the performance of the magnetic suspension damper. In addition to offering a new design concept for the construction of ship vibration and noise reduction structures, this structural solution serves as a reference for the development of magnetic suspension dampers.

Dynamic Analysis and Optimization of Vehicle-Bridge Interaction System under Road Roughness and Time Variability of Element Interpolation Function

Vehicle-induced load, as one of the main excitation factors to bridge vibration and fatigue damage, plays a vital role in the analyzing of the vehicle-bridge interaction (VBI) system, but is still limited in both spatial location and numerical value. This paper presents an improved VBI system to investigate bridge vibration and vehicle vibration considering the coherent roughness and multiple lanes excitation. The vehicle and bridge subsystems and coherent roughness road are developed and are further integrated to form the VBI system based on the displacement relationship between wheels and the bridge. Further, the solution method of the VBI system is given, and the calculation platform is constructed. Meanwhile, the natural frequencies and mode shapes, as well as the mid-span displacement of the bridge, are verified with the results calculated in commercial software. Subsequently, the responses of the VBI system are investigated under different degrees of freedom of vehicle vibration, bridge damping ratio, road roughness class, multiple lanes, and velocity. It can be concluded that road roughness and velocity have a complex nonlinear relationship with the vibration of the VBI system. Finally, the Pareto strategy is applied to find the optimized value of suspension stiffness and damping, and the depth, unit mass, and elastic modulus of the bridge to minimize the system vibration. The results show an obvious improvement in the vibration of the VBI system.

A suspension damping enhancement method based on permanent magnet damping conductive plate for superconducting maglev sled

A suspension damping enhancement method based on permanent magnet damping conductive plate for superconducting maglev sled

Analysis of damping multi-mode switching control of semi-active suspension based on digital controlled hydraulic cylinders group

In order to improve the ride comfort of vehicle suspension, this article proposes a damping multi-mode semi-active suspension system and its control method. The semi-active suspension takes a hydraulic electromagnetic shock absorber based on a digital controlled hydraulic cylinders group as the core, and realizes the switching of multiple damping modes by controlling the on-off statuses of three groups of switch solenoid valves, thus making the semi-active suspension have the characteristics of damping multi-mode adjustable. The damping characteristics corresponding to the single damping mode are verified through the prototype bench test of the shock absorber principle. On this basis, the semi-active suspension model of the vehicle is established, and a multi-mode switching control strategy of suspension damping using fuzzy control is designed. The filtered Gaussian white noise is used as the random road excitation for simulation. The simulation results show that compared with the traditional passive suspension and the semi-active suspension based on skyhook control, the damping multi-mode semi-active suspension based on the digital controlled hydraulic cylinders group can realize the switching of multiple damping modes, have good damping performance, and help to improve the vehicle ride comfortable capability.

Design and verification of low-friction and high-performance monotube magnetorheological damper

The frictional force of the suspension damper is an essential factor affecting vehicle ride comfort. As an important basic component of intelligent suspension, magnetorheological (MR) damper has the advantages of simple structure and adjustable damping performance. However, the frictional force of the MR damper is excessively high, due to the high-pressure gas to avoid the cavitation effect. If the frictional force of MR damper can be reduced, the vibration isolation performance of the intelligent suspension based on the MR damper will be further improved. In this study, a monotube MR damper with low friction and high performance is proposed and investigated. Firstly, the structural design of the low-friction MR damper is carried out, and the mathematical model of its controllable damping force and uncontrollable damping force is established. Secondly, the key structural parameters of the MR piston are optimized, and the valve system is matched based on the optimized mechanical characteristics of the piston to avoid the cavitation effect. Thirdly, bench tests are carried out on the developed low-friction MR damper. The experimental results show that the frictional force of the MR damper is very low, and no cavitation effect occurs. Finally, the system performance simulation analysis is carried out on the 1/4 vehicle semi-active suspension using the MR damper, and the influence of frictional force on the performance evaluation indexes of passive and semi-active suspensions is investigated. The simulation results indicate that the influence of frictional force on semi-active suspension is higher than that of passive suspension, and reducing the frictional force of the MR damper is of great significance to improve the performance of the semi-active suspension.

Simulation and Experiment of the Smoothness Performance of an Electric Four-Wheeled Chassis in Hilly and Mountainous Areas

This paper addresses the issues caused by traditional tractors during seeding operations, such as soil compaction, decreased soil fertility, use of unclean fuel leading to environmental pollution, and the disruption of sustainable development. In response, the study designs a compact and lightweight electric four-wheel-drive chassis for a seeding robot suitable for strip planting of soybeans and corn. Using RecurDyn(V9R2) software and MATLAB/Simulink(2020a) modules, the paper conducts simulation and analysis of the straight-line driving process of the electric four-wheel-drive chassis on hilly terrain in field conditions. The simulation results demonstrate that when the suspension stiffness is 14.4 kN/m and the damping is 900 N·s/m, the chassis achieves optimal vibration reduction and straight-line driving performance. Experimental results based on the simulation findings indicate a high consistency between the simulation and actual models, confirming that optimizing the suspension damping parameters effectively improves chassis smoothness and enhances operational quality.

Nonlinear Dynamic Mechanical Characteristics of Air Springs Based on a Fluid–Solid Coupling Simulation Method

The use of air springs has become widespread in various industries due to their exceptional superelastic properties; however, their strong nonlinear characteristics have become a hindrance to numerical simulations of air springs and have garnered increasing attention. This paper examined the nonlinear dynamic mechanical characteristics of air springs from a fluid–structure interaction perspective and verified the accuracy of the simulation analysis model through quasistatic tension and compression experiments. The average relative errors for air spring load and gas pressure were found to be 8.1% and 7.7%, respectively, which supports the validity of the model. The impact of frequency and amplitude excitations on the axial load characteristics of air springs was investigated through tension and torsion testing. The results showed that increasing the excitation frequency improves the stability of the axial load, while increasing the excitation amplitude enhances the axial load value. The change in axial compression was found to be more significant than that in axial tension, as it was affected not only by the axial load but also by the radial load, which is a key factor affecting the dynamic characteristics of air springs. A radial load analysis model was established to study the influence of frequency and amplitude excitations on the axial load characteristics of air springs. The simulation results indicated that under different amplitudes, the radial load of air springs goes through four stages: a steady period, rising period, steady period, and falling period. Additionally, under the same amplitude, the radial load value increases with an increase in frequency. This research on the dynamic load characteristics of air springs under amplitude and frequency excitations is important for their application in low-frequency and low-amplitude vibration environments, and its findings can be utilized to improve the technical parameters of air springs for suspension damping.

Design and Optimization of a New Type of Magnetic Suspension Vibration Absorber for Marine Engineering

The magnetic suspension damper, which is based on magnetic suspension technology, is receiving more and more attention from academics as active–passive hybrid damping technology develops. A new symmetric magnetic suspension structure is constructed in this study, and the accuracy of the simulation findings is confirmed by contrasting the output from finite element simulation with the theoretical formulations. On the basis of this, how the structure, size, and material of the electromagnet and armature affect the magnetic flux density, electromagnetic force, and suspension force is investigated. The structure optimization of the electromagnet and armature was performed in accordance with the simulation results, and a new symmetric magnetic suspension structure was produced. The results of the simulation demonstrate that DT4(electrical pure iron) is the ideal material for armatures and electromagnets. The reinforcing ring construction can be built up by the armature to increase suspension force. The suspension force output by the armature will be greatly increased when the size and placement of the reinforcing ring structure are right. The system stiffness adjustment range will expand at this point, enhancing the magnetic suspension damper’s functionality. This study offers novel perspectives for designing structures that reduce vibration and noise in various projects and serves as a guide to constructing magnetic suspension dampers.

A Robust Control for a Controllable Suspension System with an Input Time Delay

In this study, a state feedback robust control strategy with time delay dependence for the uncertainty, fault, and input time delay of a vehicle’s controllable suspension system is designed. Firstly, based on the working principle of the adjustable damping suspension system, the total damping force of the suspension is divided into “foundation damping force” and “controllable damping force”, taking the adjustable damping interval as the constraint boundary, which varies with the actuating velocity. Furthermore, based on the sensitivity analysis of the input time delay’s relationship with damping force disturbance, it exerts influence on the controllable damping force part. The associated uncertainty and fault are defined through linear fraction transformation and proportional gain, respectively, and the two are decoupled from the control mechanism. Then, based on the Lyapunov stability theory, a robust control law for the time-delay-dependent H∞ state feedback is designed and transformed into a linear matrix inequality convex optimization problem to solve. Finally, the feasibility and effectiveness of the proposed method are verified by designing different combinations of uncertainty and fault tests and by comparing and analyzing these with the time-delay-independent H2/H∞ robust control strategy under random and pulse road excitation.

Sensitivity Analysis and Optimization of the Hydraulic Interconnected Suspension Damping System of a Small Rescue Craft

Component parameters directly affect the dynamic characteristics of suspension systems in small rescue craft. To study and improve the vibration reduction performance of a new suspension system, sensitivity analysis and genetic algorithm (GA) optimization were performed for a three-degree-of-freedom (3-DOF) vibration reduction suspension system. The system performance was analyzed using AMESim multi-condition simulations, and the sensitivity of the system to parameters that affect its dynamic characteristics was analyzed. Furthermore, the parameters were optimized using the GA. The simulation results indicated that the hydraulic cylinder inner diameter, the piston rod diameter, the accumulator volume, the accumulator pre-charge pressure, and the damper valve aperture size all influenced the working performance of a small salvage vessel. The optimization results showed that the stability of the ship was improved by 60% and that the main hull acceleration root mean square value decreased by 2.24% as a result of the optimization. The stability and riding comfort of the small salvage ship were improved, and there was an evident stability optimization effect. The comprehensive performance of the salvage ship was significantly improved.

Bridge frequency extraction method based on contact point response of two-axle vehicle

Extracting bridge frequencies through the vehicle-bridge contact point response is more effective than that of the response of the vehicle body and wheels. However, when driving on uneven roads, the pitch effect caused by the vertical and rotational motion of the vehicle will affect the extraction of bridge frequencies. Therefore, this study establishes a two-axle vehicle model considering the suspension system and pitch effect. Meanwhile, general equations for calculating the contact point response related to the model are proposed. The accuracy of the equations is verified through numerical simulation. The result shows that extracting bridge frequencies through the contact point response is better than that of the wheel response. Three parameters, such as suspension damping, road surface roughness and vehicle speed are investigated to demonstrate the reliability of extracting bridge frequencies through the contact point response.

Design and analysis of a high-speed planetary rover with an adaptive suspension and spring damper

The development of deep space exploration has led to new exploration demands that cannot be met by traditional planetary rovers. This paper proposes a new wheeled rover that combines the advantages of passive all-wheel attachment and vibration reduction at high speeds. This rover can achieve vibration reduction in the vertical direction from ground excitation, preventing the instability of pitch and roll. Flexible wheels were used to reduce the high-frequency excitation of the ground on the rover. The design concept and mechanical principle of the proposed rover were comprehensively analyzed. A quasi-static kinematic model was developed to analyze the overstepping performance of the rover with this new design. Further, the response characteristics of the system to the ground excitation were investigated by vibration equations established using the Lagrangian method. The optimal parameters were obtained using a genetic algorithm to optimize the system with multiple objectives. Furthermore, the overstepping performance, all-wheel attachment, and vibration reduction of the planetary rover were verified through multi-body simulation. The proposed rover has considerable potential for missions such as the Mars sample return and planetary station construction.

A Linear Variable Parameter Observer-Based Road Profile Height Estimation for Suspension Nonlinear Dynamics Improvements

The accuracy of road profile height estimation has a significant impact on suspension control quality, which in turn influences handling, stability of vehicle motion and occupants' comfort. Based on our previous published work, this article designs and proposes a novel method for road profile estimation that is based on suspension nonlinear dynamics. The proposed approach first establishes the road profile height estimation model considering a real suspension design, including nonlinear characteristics of the shock absorber, bushing stiffness and damping, actual geometry of the control arms, and positioning of absorber. Unlike the conventional sprung-unsprung mass model, the real nonlinear suspension model provides much higher output prediction accuracy as computational and experimental results demonstrated. Moreover, the established estimation method and model require only two easily measurable parameters, which are the acceleration of the sprung mass and the travel of the shock absorber. While considering nonlinearity and hysteretic characteristics of the damping force, the proposed approach is based on the estimation framework of linear parameter-varying systems and establishes a sliding mode observer for estimating the road profile height. The stability of estimation error dynamics of the observer is guaranteed by the Lyapunov stability analysis. As bench-test experiments of a hardware implementation of the suspension-wheel unit validated the computational results. The tests demonstrated that the proposed method allows for real-time estimating of the road profile height in different road conditions and electric currents of the suspension damper and is robust to uncertainty of the payload.