Suspension System Research Articles

Reliability and durability assessment of bridge stay cables

AbstractAn algorithm for the reliability and durability assessment of stay cables in bridges is presented in this study enabling their probability of failure and a safe working period to be determined under various loading scenarios. The algorithm was originally developed based on data collected from an extensive structural monitoring campaign of the biggest single-pylon concrete cable-stayed bridge in Poland and used to assess the durability of its suspension system. It was then modified to be suitable for the evaluation of stay-cables subjected to wind excitation and structural reliability of the suspension system in a real steel bridge where permanent plastic deformations occurred in the anchor zones of the stay cables. The algorithm takes into account analytical models describing the stay cables and their numerical finite element models (FEM). As such, it is a universal tool having a wide range of applications, also beyond stay cables often encountered in medium- and long-span bridges forming a critical part of the civil engineering infrastructure.

Performance Characteristics of a Compact Core Annular-Radial Magnetorheological Damper for Vehicle Suspension Systems

The magnetorheological (MR) damper is a by-wire system capable of providing variable damping stiffness by responding to an apparent magnetic field. In response to the magnetic field application, the magnetorheological fluid (MR fluid) exhibited altered behavior within the damper. Typically, a damper’s internal and external valves operate in flow mode, where the flow is regulated by controlling the magnetic field. This study aims to investigate the performance characteristics of a small core annular and radial magnetorheological valve (SCARMV) designed for applications in vehicle suspension systems. The proposed design of the simplified MR valve is based on a meandering-type valve composed of multiple valve cores that have been simplified to a single core. Dynamic testing was performed on the proposed valve, which features a single rod tube damper, to investigate the damping force characteristics by varying currents and frequencies. The characteristics of the measured damping force were compared to the calculated damping force based on the pressure drop calculation and the FEMM simulation of magnetic flux. By increasing the stroke length of the valve travel is set to 10 mm at a current input of 0 A to 1.0 A, the maximum output of the MR valve damping force was approximately 1.57 kN. In addition, a mathematical model of SCARMV is presented and compared to the experimental data. Therefore, based on the experimental results, it was concluded that the usability of a compact core MR valve is reliable. However, more in-depth studies are required before these dampers can be applied to vehicle suspension systems.

Multifunctional Triboelectric Metamaterials with Unidirectional Charge Transfer Channels for Linear Mechanical Motion Energy Harvesting

AbstractConventional triboelectric generators (TEGs) have been developed to mainly harvest the energy of linear mechanical motions and convert it usually into oscillating or pulsive, but not sustainable, electrical outputs. In this study, unidirectional charge transfer mechanisms are introduced to develop a triboelectric mechanical metamaterial (TMM) with sustainable electrical outputs. Density functional theory and experimental analyses demonstrate three minimum necessary components of TMMs fabricated by only two triboelectric materials (i.e., copper and PTFE) to generate sustainable electrical outputs. Under a wide range of compression‐tension strain of ±50%, the maximum open‐circuit voltage, short‐circuit current, and volumetric power density are 3860 V, 8 µA, and 365.3 kW m−3, respectively. Different from most conventional cellular solids, the mechanical energy dissipation of the TMMs increases quadratically with the unit cell number. High volumetric electromechanical efficiency is achieved when the unit cell is miniaturized. In addition to energy harvesting and mechanical energy dissipation, TMMs can sense the displacement by counting the number of distinctive peaks in the short‐circuit charge transfer or reaction force versus time curves. The extreme electromechanical functionalities of the TMMs facilitate their applications in intelligent suspension systems, miniaturized green power sources, and self‐sensing energy harvesters.

Novel approaches in developing sustainable and cost-effective semi-active suspension systems for smart vehicles—A review

The dynamic evolution of automotive technology necessitates integrating intelligent systems in suspension systems to enhance vehicle dynamic performance and environmental sustainability. The major challenge in the vehicle suspension design is to achieve an optimum tradeoff between riding comfort and ground holding with the available rattle space. Semi-active suspension systems (SASSs), which meet these requirements more effectively than passive and active systems, have gained prominence for their potential. Different SA control strategies and dampers have been developed to enhance dynamic performance. The optimal control strategies and design parameters improve the responsiveness of SASSs in the vehicle dynamic performance. The algorithms attempt to avail the full potential of various dampers controlled electronically. The accurate representation of nonlinearities in mathematical modeling with noise mitigation enhances the practical implementation of novel controllers in SASSs. This review investigates the forefront of research and development in SASSs, focusing on innovative strategies to make these systems more sustainable, adaptive, and cost-effective for smart vehicles. Semi-active magnetorheological dampers have more commercial applications than other dampers, but the high cost makes them unaffordable for economical cars. Several researchers have attempted to develop inexpensive, high-performance dampers that can vary damping coefficients precisely for different road conditions. Real-time energy harvesting-based dampers for sustainable electric mobility are under development. Commercially available SASSs are less expensive than active suspensions but they have limited applications than passive suspensions. The low market share of existing SASSs and their regenerative inability are the major drawbacks in making it a sustainable suspension system. The novel strategies attempted to develop an effective smart suspension system and its limitations are discussed in this review. The next generation of SASSs that aligns with the global drive towards smarter, greener, and economical vehicles is identified.

ELLIPSOIDAL DESIGN OF SLIDING MODE CONTROL FOR CAR ACTIVE SUSPENSION SYSTEM

The issue of state feedback sliding mode control (SMC) for a particular kind of active quarter-car suspension system is discussed in this work. The suspension systems' dynamic system is built with the three control objectives of maximal actuator control force, suspension deflection, and ride comfort in mind. The next step is to build the state-feedback controller with the disturbance (vibration) attenuation level in mind to guarantee the asymptotic stability of the closed-loop system. The algorithm for SMC design is introduced. It is predicated on choosing the sliding surface correctly using the invariant ellipsoid approach. The system motion in the sliding mode is guaranteed to be little affected by mismatched disturbances according to the control architecture. Furthermore, the presence of admissible controllers is articulated in terms of LMIs through the use of Lyapunov theory and the linear matrix inequality (LMI) technique. The objective is to create a desired dynamic state-feedback controller when these requirements are met. Lastly, a quarter-car model is used to illustrate how successful a suggested approach is.

Influence of the geometric parameters of the connecting pipeline on the stiffness and damping of the pneumatic spring suspension at high-speed rolling stock

The study presents investigation is the pneumatic spring suspension system of diesel train DPKr-3. The research aims to estimate the influence of track irregularities on the pneumatic spring dynamic stiffness and its damping coefficient at 170–250 km/h speeds. The pneumatic spring suspension system characteristics were studied using an improved mathematical model of the system ‘rolling stock-track’. The pneumatic spring ‘force-strain’ relations are obtained at different values of the connecting pipeline diameter and length at high speeds. It was determined that increasing a connecting pipeline diameter from 20 to 40 mm and a speed change from 170 to 250 km/h causes decreasing a spring dynamic stiffness. It is shown that at a speed range from 170 to 250 km/h and a connecting pipeline diameter from 20 to 40 mm, a change in a pipeline length from 3 to 6 m does not lead to significant changes in stiffness. It was found that in the range of speeds from 170 to 250 km/h, the damping coefficient has maximum values with a diameter of the connecting pipeline from 25 to 30 mm.

Active disturbance rejection control based on BP neural network for suspension system of electromagnetic suspension vehicle

Active disturbance rejection control based on BP neural network for suspension system of electromagnetic suspension vehicle

Robust Static Output Feedback Control of a Semi-Active Vehicle Suspension Based on Magnetorheological Dampers

This paper proposes a novel design method for a magnetorheological (MR) damper-based semi-active suspension system. An improved MR damper model that accurately describes the hysteretic nature and effect of the applied current is presented. Given the unfeasibility of installing sensors for all vehicle states, an MR damper current controller that only considers the suspension deflection and deflection rate is proposed. A linear matrix inequality problem is formulated to design the current controller, with the objective of enhancing ride safety and comfort while guaranteeing vehicle stability and robustness against any road disturbance. A series of experiments demonstrates the enhanced performance of the proposed MR damper model, which exhibits greater accuracy than other state-of-the-art damper models, such as Bingham or bi-viscous. An evaluation of the vehicle behavior under two simulated road scenarios has been conducted to demonstrate the performance of the proposed output feedback MR damper-based semi-active suspension system.

An improved multi-objective artificial physics optimization algorithm based on R2 indicator and its application

Artificial Physics Optimization (APO) algorithms in solving constrained multi-objective problems often encounter challenges such as uneven population distribution and imbalances between global and local search capabilities. To address these issues, we propose the Constrained Rank Multi-Objective Artificial Physical Optimization based on the R2 indicator (R2-ICRMOAPO) algorithm. This algorithm integrates non-dominated sorting with the R2 indicator and updates the external storage set using the contribution value derived from the R2 indicator formula, ensuring both set distribution and convergence. It also dynamically adjusts inertia weights and gravitational factors to enhance its global and local search capabilities. To evaluate the performance of the R2-ICRMOAPO algorithm, we compared it with four other multi-objective optimization algorithms using standard test functions. The results indicate that it demonstrates superior distribution and optimization performance. Furthermore, we applied it to optimize the parameters of a hydro-pneumatic suspension system. The experimental results show that it can reduce the root mean square value of car body vertical acceleration by approximately 21.4% and the root mean square value of dynamic tire load by about 19.6%. This reduction effectively enhances vehicle smoothness within a reasonable range. Consequently, these results confirm the feasibility of the R2-ICRMOAPO algorithm to solve practical problems.

Linear parameter varying μ synthesis robust control of CDC semi‐active suspension system for nonlinearity and uncertainty

AbstractBecause the continuous damping control (CDC) semi‐active suspension system has complex nonlinear and uncertain characteristics that can significantly affect the performance of the system. And in the controller design process, achieving a balance of multiple performance objectives is often difficult. Therefore, this paper designs a linear parameter varying (LPV) μ synthesis robust controller for the vibration suppression and multi‐objective control of a 7‐degree‐of‐freedom (7‐DOF) vehicle suspension system equipped with CDC dampers. Firstly, the nonlinear force model of the solenoid valve CDC damper is developed based on the actual damping variation. Considering the nonlinear forces of the coil springs, the nonlinear model of the 7‐DOF suspension system is expressed as LPV form. Further, the linear fractional transformation (LFT) method is used to analyze and reconstruct the system model for multiple parameter uncertainties of the suspension. The actuator time delays are also simulated through a frequency domain transfer function, which is considered to be an unmodeled dynamic at the input of the system. Finally, an LPV‐μ synthesis robust controller based on nonlinearity and mixed uncertainty is designed to improve car ride comfort and achieve the best relationship between comfort and handling stability. Simulation and experimental results under random disturbance conditions show that the LPV‐μ synthesis controller has better anti‐jamming performance and controllability compared to the H∞ controller and μ synthesis controller.

Performance Verification and Evaluation of Semi-Active Actuator System Using Quarter Car Lab Simulation with RLDA Data

This study outlines a methodology for determining the durability specifications of electronically controlled dampers by examining performance degradation observed on actual driving roads. It identifies areas of performance decline and the primary causes affecting major actuator dampers. Traditionally, the durability performance of automobile parts has been assessed by calculating damage based on load profiles. However, analyzing actual road conditions is essential because the control commands of electronically controlled suspension systems change in real time according to load conditions. Simulations based on Road Load Data Acquisition (RLDA) use statistically independent representative road surfaces to assess damper deterioration performance. Following this analysis, a rig test of the damper is performed to establish the durability specifications for damper actuator products. The primary form of performance degradation observed was a change in the tensile damping force, which was more substantial than the degradation observed on the compression side. Oil leakage and cavitation were identified as significant influencing factors from a Failure Mode and Effects Analysis (FMEA) perspective. The study concludes that additional design research is necessary, focusing on damper oil and leakage, while also considering the control algorithm’s effects in designing electronically controlled dampers.

Optimization of Dynamic Characteristics of Rubber-Based SMA Composite Dampers Using Multi-Body Dynamics and Response Surface Methodology

The suspension system of a commercial vehicle cab plays a crucial role in enhancing ride comfort by mitigating vibrations. However, conventional rubber suspension systems have relatively fixed stiffness and damping properties, rendering them inflexible to load variations and resulting in suboptimal ride comfort under extreme road conditions. Shape memory alloys (SMAs) represent an innovative class of intelligent materials characterized by superelasticity, shape memory effects, and high damping properties. Recent advancements in materials science and engineering technology have focused on rubber-based SMA composite dampers due to their adjustable stiffness and damping through temperature or strain rate. This paper investigates how various structural parameters affect the stiffness and damping characteristics of sleeve-type rubber-based SMA composite vibration dampers. We developed a six-degree-of-freedom vibration differential equation and an Adams multi-body dynamics model for the rubber-based SMA suspension system in commercial vehicle cabins. We validated the model’s reliability through theoretical analysis and simulation comparisons. To achieve a 45% increase in stiffness and a 64.5% increase in damping, we optimized the suspension system’s z-axis stiffness and damping parameters under different operating conditions. This optimization aimed to minimize the z-axis vibration acceleration at the driver’s seat. We employed response surface methodology to design the composite shock absorber structure and then conducted a comparative analysis of the vibration reduction performance of the optimized front and rear suspension systems. This study provides significant theoretical foundations and practical guidelines for enhancing the performance of commercial vehicle cab suspension systems.

A high-precision two-parameter road roughness grading and identification methodology across multiple frequency intervals

Based on a dual track road shape meter, various road roughness was measured. It was discovered that the road grading method in ISO 8608 assumes a constant waviness value of W = 2 with a one-straight line approximation, but it could not accurately fit and grade the measured road roughness. A high-precision piecewise fitting function for the low-frequency and high-frequency parts of the road roughness power spectral density (PSD) is established. A high-precision two-parameter grade method in multiple frequency bands for road roughness is proposed ( G q( n0), the geometric average of the road roughness index at n0, W, the waviness, is the slope of the road roughness PSD fitting expression in the double logarithmic coordinate system). According to the vehicle driving performance obtained by simulation, the grading method is verified. For Paved and Undulating roads, compared to the road roughness classification method in ISO 8608, the performance simulated based on the grade results of the two parameters grading method are closer to the performance simulated based on the measured road roughness. The grading method proposed in this paper can more accurately fit and classify the measured road roughness. The influence of these parameters at each frequency interval on vehicle driving performance is studied. A two-parameter identification method for road roughness PSD at variable intervals over a large frequency range is proposed. In the double logarithmic coordinate system, this method divides the selected spatial frequency into three sub-intervals along the abscissa, in each sub-interval, the parameters G q( n0) and W are identified separately. This method can provide effective control inputs for the vehicle’s active or semi-active suspension system.

Accelerometer-Based Pavement Classification for Vehicle Dynamics Analysis Using Neural Networks

This research examines the influence of various pavement types on vehicle dynamics, specifically concentrating on vertical acceleration and its implications for unsprung mass, including the wheels and suspension system. The objective of this project was to categorize pavement types with accelerometer data, enabling a deeper comprehension of the impact of road surface conditions on vehicle stability, comfort, and mechanical stress. Two categorization methods were utilized: a neural network and a multinomial logistic regression model. Accelerometer data were gathered while a car navigated diverse terrain types, such as grates, potholes, and cobblestones. The neural network model exhibited exceptional performance, with 100% accuracy in categorizing all surface types, while the multinomial logistic regression model reached 97.14% accuracy. The neural network demonstrated exceptional efficacy in differentiating intricate surface types such as potholes and grates, surpassing the logistic regression model which had difficulties with these surfaces. These results underscore the neural network’s effectiveness in the real-time categorization of road surfaces, enhancing the comprehension of vehicle dynamics influenced by pavement conditions. Future studies must tackle the difficulty of identifying analogous surfaces by enhancing methodologies or integrating more data attributes for greater precision.

Event-triggered finite-time guaranteed cost control of uncertain active suspension vehicle system

The event-triggered finite-time guaranteed cost control problem is important for an uncertain active suspension vehicle system. Existing works on the design of finite-time controllers for active suspension systems have not been extended to the event-triggered finite-time guaranteed cost control problem for uncertain active suspension systems. In this paper, we investigate the problem of designing an event-triggered finite-time guaranteed cost controller for an uncertain active suspension system. A new event-triggered controller and a cost function are first defined. Then, some new sufficient conditions for designing an event-triggered state feedback controller are derived based on linear matrix inequalities to stabilise the closed-loop systems while guaranteeing an adequate cost level of performance. Finally, numerical results and simulations are given to illustrate the effectiveness of the proposed method.

Stability Analysis of Electromagnetic Suspension Systems Coupled with Flexible Frames: Modeling, Control, Analysis and Experimentation

The stability of the suspension is a key challenge for the application and promotion of electromagnetic suspension technology, especially when it operates in conjunction with a flexible structure, which significantly increases the system's complexity. This paper abstracts the characteristics of the coupling conditions between an electromagnetic suspension system and a flexible structure and designs and constructs an experimental apparatus that includes an electromagnet and a simulated flexible structure with adjustable stiffness and inertia. Based on the Lyapunov method, the central manifold theorem, and the Poincaré method, the stability of the electromagnetic suspension system and the conditions for Hopf bifurcations are derived. Finally, through reasonable experimental design and data analysis, the correctness of the theoretical analysis conclusions is validated, providing references for the engineering applications of electromagnetic suspension systems.

Review Paper on Development of Mini Refrigerator

Abstract: This project focuses on the innovative development of a regenerative magnetic suspension system that uses permanent magnets to capture energy from the vibrations and movements of vehicles, aiming to improve energy efficiency and sustainability within the automotive sector. Unlike conventional suspension systems that dissipate energy as heat, this design utilizes highperformance neodymium magnets and wound copper coils to convert mechanical energy into electrical energy via electromagnetic induction as the vehicle moves across varying terrains. The energy recovered through this process can potentially power auxiliary vehicle systems such as sensors, lights, and infotainment units, thereby contributing to overall vehicle efficiency. Preliminary simulations and calculations indicate a substantial potential for energy recovery, positioning the system as a cost-effective and practical solution that can be integrated into existing vehicle architectures with minimal modifications. By leveraging readily available materials, this project addresses the challenges of energy waste in conventional suspensions while promoting sustainable practices. The research not only advances regenerative technologies within the automotive industry but also paves the way for future innovations in vehicle design and broader engineering applications

Adaptive robust constraint-following control method for improving carbody hunting stability of high-speed trains

The low-frequency carbody hunting motion of high-speed trains (HSTs) frequently occurs due to the complex operating environment and deterioration of wheel–rail contact conditions. It not only affects ride comfort but also poses a risk of derailment safety accidents for HSTs. In such scenarios, traditional passive suspension systems struggle to ensure satisfactory dynamic performance of HSTs. However, active suspension systems can offer an effective solution. To enhance the low-frequency carbody hunting stability and environmental adaptability of HSTs, this study proposes a novel adaptive robust displacement inequality constraint following control (AICFC) method for active suspension utilising the beneficial nonlinearity inspired by bio-inspired structures (BIS). The effectiveness of the proposed AICFC-BIS method is validated through numerical simulations comparing it with other control strategies. Simulation results show that the AICFC-BIS method can effectively suppress low-frequency carbody hunting motion and improve the dynamic performance of HSTs. Compared with conventional passive suspensions and other active suspensions, HSTs equipped with AICFC-BIS active suspension exhibit significantly reduced operational safety risk and improved ride comfort indices while being energy efficient.

Review Paper on Agricultural Terrain Traversal Rocker Bogie Mechanism

Abstract: This paper details the design and implementation of a terrain traversal system leveraging the rocker-bogie mechanism, specifically tailored for agricultural applications where uneven terrain presents significant challenges. The rocker-bogie suspension system, renowned for its application in planetary rovers, is innovatively adapted to navigate the complexities of agricultural fields. The primary objective of this research is to create a prototype that minimizes soil disturbance while effectively maneuvering over obstacles such as rocks, furrows, and varying soil conditions. Through this approach, the prototype aims to enhance operational efficiency in critical agricultural tasks, including planting, monitoring, and maintaining crops. The system's design incorporates advanced navigation capabilities, potentially integrating sensors for obstacle detection and GPS for precise positioning. This research addresses the pressing need for low-cost, scalable solutions in the realm of agricultural mechanization, ultimately contributing to improved productivity and reduced labor costs in farming operations. The findings from this study are anticipated to provide significant insights into the future of agricultural technology, paving the way for further innovations in automated systems that can adapt to the dynamic challenges of modern agriculture. The successful deployment of this prototype not only underscores the feasibility of the rocker-bogie mechanism in agricultural settings but also highlights its potential to revolutionize practices in the industry.

Generalized [formula omitted] observer for road profile estimation in the automotive suspension system

This study develops a generalized H2 observer to estimate the road profile in the semi-active automotive suspension system. The dynamics of the quarter-car model are represented in the descriptor nonlinear parameter-varying system framework, with the road profile as a system's state that is of arbitrary dynamics. Then, a road profile estimation method is designed by using a generalized H2 observer, which utilizes the onboard accelerometers as the observer's input. The adverse impact of measurement noises on the accuracy of estimation results is alleviated via the generalized H2 framework. The proposed observer is designed by solving an LMI-based constrained optimization problem. Frequency domain analysis and time domain simulations illustrate the efficiency of the proposed strategy