Browse Topic: Semi-active suspension systems

Items (188)

Experimental Assessment of a Controlled Slippage Magnetorheological Automotive Active Suspension for Ride Comfort

8/23/2022

Active suspensions can alter the dynamic behavior of a vehicle in real time to respond optimally to any given operating scenario. Today’s active suspension technologies such as hydraulics, rotary electromagnetics, and linear electromagnetics do offer performance gains but these gains are outweighed by important disadvantages including high power consumption, low quality of force, and high costs and weights. Controlled slippage magnetorheological (MR) actuators are an emerging alternative actuation technology that is light, compact, power dense, and produces a high-quality force, making it ideal for active suspension applications. This article conducts an in-depth experimental assessment of the potential of MR actuators to increase vehicle ride comfort quality when used as active suspensions. Four high power MR actuators are installed on a BMW 330Ci and tests are performed on a closed road. Results show that with an impedance controller, comfort is increased by 67% at 65 km/h and by 61% at 80 km/h. These results compare favorably with the best-in-class electromagnetic active suspension technologies reported to date and suggest that MR actuators are promising for automotive active suspensions.

Turcotte, Jérôme, East, William, Plante, Jean-Sébastien

testprint9

SAE-PP-010034/27/2022

testprint9

Mutagaana, Festo

preprint2

SAE-PP-009964/27/2022

preprint2

Mutagaana, Festo

automobile's nviehf

SAE-PP-0047610/6/2021

Mutagaana, Festo

SM0003-Test

SAE-PP-004579/25/2021

Current automobile's auto-transmission has problems of defects and cost reduction because of welding process and very complicated assembly process due to individualized transmission piston and sealing components. Also, size and heavy weight of transmission piston components are the source of low mileage because they are made of aluminum, steel material. In this study, therefore, we perform structure design for piston sealing system which integrates piston and sealing material for automobile's lightweight auto-transmission. Also performed stress analysis through finite element analysis to secure required suitable strength when internal pressure is applied after assemble.

Mutagaana, Festo

SM0001-Test

SAE-PP-004549/25/2021

Mutagaana, Festo

Testing-legacypublishing

SAE-PP-003766/22/2021

ajglkwn

SintzUSER, Jeneane

6.0.120 - Investigation of the Applicability of Numerical Noise Prediction of an Axial Vehicle Cooling Fan

SAE-PP-002752/4/2021

This paper focuses on the applicability of numerical prediction of sound radiation caused by an axial vehicle cooling fan. To investigate the applicability of numerical methods, a hybrid approach is chosen where first a CFD simulation is performed and the sound radiation is calculated in a second step. For the acoustic simulation an integral method described by Ffowcs-Williams-Hawkings is used to predict the sound propagation in the far-field. The simulation results are validated with experiments. The corresponding setup in experiments and simulation represents an overall system which includes the cooler, the cooling fan and a combustion engine dummy. To optimize the economical applicability in terms of simulation setup and run time, different approaches are investigated. This includes the simulation of only one blade using a periodic boundary condition as compared to the whole fan geometry. In the CFD simulation an SAS-turbulence-model is applied. The results show that this is a very useful approach considering the challenges in prediction of numerical sound. On the one hand, the turbulence model has to solve small scales which cause sound in high frequency ranges which leads to a small time increment and a high grid resolution. On the other hand, a long simulation time for predicting sound in low frequency ranges is needed. Additional to the sound propagation in the far-field, it is a benefit to be able to localize the acoustic sources with regards to geometrical optimization. For this, the divergence of the Lighthill Tensor is calculated on the CFD grid.

Mutagaana, Festo

Vibration Control of Semi-Active Vehicle Suspension System Incorporating MR Damper Using Fuzzy Self-Tuning PID Approach

2020-01-10824/14/2020

In this paper, a nonlinear semi-active vehicle suspension system using MR fluid dampers is investigated to enhance ride comfort and vehicle stability. Fuzzy logic and fuzzy self-tuning PID control techniques are applied as system controllers to compute desired front and rear damping forces in conjunction with a Signum function method damper controller to assess force track-ability of system controllers. The suggested fuzzy self-tuning PID operates fuzzy system as a PID gains tuner to mitigate the vehicle vibration levels and achieve excellent performance related to ride comfort and vehicle stability. The equations of motion of four-degrees-of-freedom semi-active half-vehicle suspension system incorporating MR dampers are derived and simulated using Matlab/Simulink software. Control performance criteria including bounce and pitch motions are evaluated in both time and frequency domains in order to quantify the effectiveness of proposed system controllers under bump and random road disturbances. Fuzzy self-tuning PID controller gives a better force tracking than fuzzy logic. The performance of both controlled semi-active suspension systems using MR dampers is compared with MR passive and conventional passive to show the efficiency of the proposed controlled suspension systems. The simulation results prove that the semi-active MR suspension system controlled using fuzzy self-tuning PID controller can offer significant improvements of ride comfort and vehicle stability among all investigated systems.

Gad, Ahmed Shehata, Oraby, W., Metered, H.

Second-Order Sliding Mode Controller for Performance Analysis of Quarter Car Magnetorheological Suspension System

2020-01-10054/14/2020

Soosairaj, Arockia Suthan, K, Arunachalam

Control Performance of Damping and Air Spring of Heavy Truck Air Suspension System with Optimal Fuzzy Control

10-04-02-00132/28/2020

The air suspension system of heavy trucks not only improves the vehicle’s ride comfort but also reduces the negative impact on the road surface. In order to evaluate the performance of the control damping (CD) and the control air spring (CAS) of the vehicle air suspension system on the ride comfort and the road friendliness, a three-dimensional (3D) nonlinear dynamic model with 14 degrees of freedom (DOF) of the heavy trucks and optimal fuzzy control (OFC) with control rules optimized by the genetic algorithm (GA) are proposed in this study. The root mean square (RMS) acceleration response of the tractor and the dynamic load coefficient (DLC) at the wheel axles are chosen as objective functions under the various operating conditions. Contrastive analysis of the RMS and DLC values with the passive (P), CD, and CAS methods of the air suspension system is carried out respectively. The research result shows that both the CD and CAS methods remarkably improve the ride comfort and road friendliness of the heavy trucks in comparison with P, especially the CAS method has an obvious effect on mitigating the road damage in comparison with the CD method; conversely the CD method is better than the CAS method to improve the tractor’s ride comfort under different operating conditions.

Nguyen, Vanliem, Jiao, Renqiang, Zhang, Jianrun

Crank-Lever Electromagnetic Damper (CLEMD) Design for Automobile Suspension System

06-13-01-00022/4/2020

An effective damper is among the most important components of the suspension system. It ensures the right amount of damping force is acting on the suspension system to provide comfort to the passengers and proper road holding to tires. Unfortunately, the energy absorbed by the dampers from the suspension system gets wasted in the form of heat. In this article, it is proposed to use innovative electromagnetic damper (EMD) with a crank-lever mechanism to recover energy from the suspension system. The goal is to develop a lightweight design of EMD that can recover a high amount of power. For the design, an off-road vehicle is used since in off-road vehicles the amount of power wasted in the suspension system is high. Three different design approaches are used, which include single-stage gearbox type, two-stage gearbox type, and three-stage gearbox type of CLEMD. Out of them, the best design, i.e. three-stage gearbox type of CLEMD is selected because of minimum weight and inertia of the components. This article is focused on the design and analysis of the three-stage gearbox type of CLEMD. On the basis of the output of numerical simulations of vehicle model, specifications for crank-lever electromagnetic damper (CLEMD) are driven and design is carried out. Also, performance analyses of CLEMD are carried out by interfacing model of CLEMD with the model of a vehicle. The advantage of CLEMD is it can act as an actuator to provide active force in an active suspension system.

Todmal, Prashant Eknath, Melzi, Stefano

A Study of the Control Logic of Electronically Controlled Suspension for Motorcycle

2019-32-05691/24/2020

Electronically controlled suspensions are expected to improve driving performance as the damping characteristics of the suspension can be adjusted in real time to respond to road conditions. This paper reports the results of testing the suspension control logic for improving ride quality, especially when driving on rough roads, using an internally developed riding simulator. The skyhook theory is widely known as a control logic for reducing vibration when driving a four-wheeled vehicle on a rough road, which we utilized in our riding simulator to examine the vibration reduction effects when applying control logic for motorcycle suspensions. The test results show that the skyhook theory can be applied in motorcycles. However, sensors for suspension systems that can be installed in mass-produced motorcycles are severely limited in terms of cost and space. Therefore, we examined a control logic based on skyhook theory that can reduce vibration even with a simple and inexpensive sensor system. A novel control logic was successfully designed that implements the relationship between the suspension stroke speed and the vertical acceleration of the sprung mass from the dynamics of the vehicle body when driving on rough roads. This control logic was tested using the riding simulator, and it was shown that this new control logic can reduce vibration to almost the same level as the original skyhook theory.

Terada, Takenori, Ichikawa, Kazuhiro, Kato, Hideyuki, Iwamoto, Taro

Modelling and Simulation of Vehicle Suspension System with Variable Stiffness Using Quasi-Zero Stiffness Mechanism

10-04-01-000312/2/2019

The dynamics and comfort of a vehicle closely depends on the stiffness of its suspension system. The suspension system of a vehicle always had to trade-off between comfort and performance of a vehicle; since for comfort a softer suspension is preferred which in turn decreases the aerodynamics and cornering performance and increases the ride height of the vehicle; whereas in stiffer suspension the ride height can be lowered, but forces due to bumps are transferred all the way up to the drivers cabin. This article aims to design a vehicle suspension model with variable stiffness using quasi-zero stiffness (QZS) mechanism and study its force-displacement characteristics and minimize the fundamental stiffness of the suspension system. The model developed uses the principle of negative stiffness to achieve low stiffness for the softer suspension system. The mechanism designed comprises of a pushrod suspension system with three parallel springs attached to one end of the rocker arm, one primary coil spring is mounted perpendicular to the rocker arm and the other two secondary plate springs are attached to the primary coil spring. In parallel, stiffness of all the three springs are added, giving stiffer suspension when required at low ride heights and higher cornering performance. For decreasing the stiffness, an actuator is used to position the secondary springs such that negative stiffness is produced, decreasing the stiffness of the system. The geometry stated above is modelled in Catia and simulated in MATLAB/Simulink. Graphs of force vs. displacement and stiffness vs. displacement are studied for both the conditions. A comparative study of conventional suspension and modelled suspension system is done.

Saini, Mohit

Minimizing Power Consumption of Fully Active Vehicle Suspension System Using Combined Multi-Objective Particle Swarm Optimization

2019-01-50777/16/2019

This paper introduces an optimum design for a feedback controller of a fully active vehicle suspension system using the combined multi-objective particle swarm optimization (CMOPSO) in order to minimize the actuator power consumption while enhancing the ride comfort. The proposed CMOPSO algorithm aims to minimize both the vertical body acceleration and the actuator power consumption by searching about the optimum feedback controller gains. A mathematical model and the equations of motion of the quarter-car active suspension system are considered and simulated using Matlab/Simulink software. The proposed active suspension is compared with both active suspension system controlled using the linear quadratic regulator (LQR) and the passive suspension systems. Suspension performance is evaluated in time and frequency domains to verify the success of the proposed control technique. The simulated results reveal that the proposed controller using CMOPSO grants a significant enhancement of ride comfort and road holding, and reduction of actuator power consumption.

Elsawaf, Ahmed, Metered, H., Abdelhamid, A.

A Novel Three Steps Composited Parameter Matching Method of an Electromagnetic Regenerative Suspension System

2019-01-01734/2/2019

The electromagnetic regenerative suspension has attracted much attention recently due to its potential to improve ride comfort and handling stability, at the same time recover kinetic energy which is typically dissipated in traditional shock absorbers. The key components of a ball-screw regenerative suspension system are a motor, a ball screw and a nut. For this kind of regenerative suspension, its damping character is determined by the motor's torque-speed capacity, which is different from the damping character of the traditional shock absorber. Therefore, it is necessary to establish a systematic approach for the parameter matching of ball-screw regenerative suspension, so that the damping character provided by it can ensure ride comfort and handling stability. In this paper, a 2-DOF quarter vehicle simulation model with regenerative suspension is constructed. The effects of the inertia force on ride comfort and handling stability are analyzed. A novel three steps composited matching method is proposed to determine the non-linear damping character of the ball-screw electromagnetic regenerative suspension. In this composited method, a genetic algorithm is adopted to calculate the optimal damping coefficient within its linear range, probability statistics is applied to determine the constant damping force provided by the motor over constant damping range, and the decreasing damping force range is determined by the motor speed ratio. Through the above three steps, system parameters including the motor rated power and the lead of ball screw are determined. The effectiveness of the systematic parameter selection approach is validated through simulation.

Cui, Dandan, Yongchang, Du

Vibration Control of an Active Seat Suspension System Integrated Pregnant Woman Body Model

2019-01-01724/2/2019

Proportional-integral-derivative (PID) controller is effective, popular and cost effective for a lot of scientific and engineering applications. In this paper, PID and fuzzy-self-tuning PID (FSTPID) controllers are applied to improve the performance of an active seat suspension system to enhance the pregnant woman comfort. The equations of motion of thirteen-degrees-of-freedom (13-DOF) active seat suspension system incorporating pregnant woman body model are derived and simulated. PID gains are tuned and estimated using genetic algorithm (GA) to formulate GA PID controller. In FSTPID, fuzzy logic technique is used to tune PID controller gains by selecting appropriate fuzzy rules using Matlab/Simulink software. Both controlled active seat suspension systems are compared with a passive seat suspension. Suspension performance is evaluated under bump and random road excitations in order to verify the success of the proposed controllers. Theoretical results reveal that the proposed controllers using GA PID and FSTPID grant a significant enhancement of the pregnant woman comfort and her fetus.

Ali, Shaimaa A., Metered, H., Bassiuny, A. M, Abdel-Ghany, AM

A Study of Triple Skyhook Control for Semi-Active Suspension System

2019-01-01684/2/2019

The research described in this paper focused on improving occupant ride comfort and road holding by suppressing sprung and unsprung vibration using a semi-active suspension system. It has been reported that occupants tend to perceive vertical vibrations in a frequency range between 4 and 8 Hz as uncomfortable (described below as the “mid-frequency range”). Previous research into semi-active suspension system has focused on reducing vibration in this mid-frequency range, as well as close to the sprung resonance frequency of between 1 and 2 Hz. Skyhook damper (SH) control is a typical ride comfort control used to damp vibration close to the sprung resonance frequency. However, since SH control is not capable of damping vibration in the mid-frequency range, the shock absorbers are configured with a lower damping factor. This helps to achieve a good balance between reducing vibration close to the sprung mass resonance and in the mid-frequency range. In contrast, it has the trade-off effect of increasing unsprung vibration. The triple skyhook (tSH) control, which suspends the vehicle using three virtual elements (i.e., springs, dampers, and inerters), has been proposed to help resolve these issues. This control is capable of reducing sprung vibration over a wide range without altering the suspension characteristics. Furthermore, this control only uses information from sprung mass sensors, and can be configured using simple control laws. The purpose of this research is to simultaneously satisfy requirements for both ride comfort and road holding by applying tSH control to a vehicle with a semi-active suspension system. This was accomplished by driving a test vehicle over an irregular road surface, and analyzing the vehicle roll, pitch, and heave, as well as the unsprung vibration frequency. As a result, this research confirmed that the proposed control improves ride comfort by reducing sprung vibration over a wide frequency range. In addition, by suppressing deterioration in unsprung vibration, the control improves the road-holding performance compared to the conventional SH control.

Shimoya, Naoto, Katsuyama, Etsuo

Model Reference Control for Active Suspension System

2019-01-01654/2/2019

The objective of this study is to develop a Model Reference Control (MRC) strategy for active suspension System. The MRC strategy employs both the suspension look-ahead preview and wheelbase preview concepts, and the methodology of the MRC based on the ideal hybrid skyhook-groundhook concept. The study performed using a 13 degree-of-freedom (DoF) vehicle vertical dynamics model including the active suspension actuators masses. The engine mass, driver seat and anti-roll bar are considered in the model. The MRC strategy uses eight Proportional-Integral-Derivative (PID) controllers for both body and wheel control. A gradient-based optimization algorithm is applied to obtain the controller parameters using a cost function including both ride comfort and road holding performance. Comparison between the active suspension system provided with proposed MRC strategy, the ideal hybrid skyhook-groundhook suspension system, and the passive suspension system in terms of ride comfort and road holding is performed. The obtained results showed that, the proposed MRC strategy with the PID controllers are able to track the performance of the ideal hybrid skyhook-groundhook system, and provided significant improvements in both ride comfort and road holding.

Kaldas, Mina M.S., Soliman, Aref M.A., Abdallah, Sayed A., Amien, Fomel F.

An Optimization of Suspension Linkages for Wheel-Legged Vehicle

2019-01-01674/2/2019

The guiding mechanism of vehicle suspension can keep the wheels moving along planned trajectory. The geometrical design of the reasonable suspension guide mechanism can reduce the vibration transmitted to the body, improve trafficability and handling stability. The vehicle suspension design method was applied to the wheel-legged vehicle, enhancing ride performance. The optimization of suspension hard points can be obtained by using single variable method, adjusting each hard point coordinate independently. It is also widely recommended by using intelligent algorithm to solve well-designed multi-objective parameter optimization function. In this study, the multi-objective parameter optimization function was solved by using the NSGA-II (Non-dominated Sorted Genetic Algorithm-II). Computer simulations with half-car model were used to support the analysis in this study. ADAMS multibody dynamics software was also used to verify the reliability of the results. The advantages in using this methodology are emphasized by an example of the multi-objective parameter function design of suspension hard points and the results are compared with primary values in ADAMS. It was found that the optimized suspension was substantially improved in the respect of wheel alignment, wheelbase and roll center change. By solving the problem of multi-objective function, the NSGA-II exhibited higher efficiency and accuracy than traditional genetic algorithm. The validity of the algorithm was verified. Besides, this paper presented an alternative methodology to improve the design of intelligent robot. More vehicle design methods can be applied to the intelligent vehicle-robot domain. The process of wheel-legged vehicle suspension design provides reference for relevant applications.

Ma, Fangwu, Nie, Jiahong, Yang, Yu, Wang, JiaWei, Wu, Liang

Application of a Preview Control with an MR Damper Model Using Genetic Algorithm in Semi-Active Automobile Suspension

2019-01-50062/5/2019

A non-linear mathematical model of a semi-active (2DOF) vehicle suspension using a magnetorheological (MR) damper with information concerning the road profile ahead of the vehicle is proposed in this paper. The semi-active vibration control system using an MR damper consists of two nested controllers: a system controller and a damper controller. The fuzzy logic technique is used to design the system controller based on both the dynamic responses of the suspension and the Padé approximation algorithm method of a preview control to evaluate the desired damping force. In addition, look-ahead preview of the excitations resulting from road irregularities is used to quickly mitigate the effect of the control system time delay on the damper response. Adaptive neuro-fuzzy inference system (ANFIS) inverse model without preview, ANFIS inverse model with preview, and ANFIS inverse model with preview and optimization strategies are used to design the damper controller to evaluate different values of the command voltage based on the tracking of a desired damping force to compare which of them gave the best behavior of the MR damper. Each one of these strategies is used in conjunction with the system controller to evaluate the effectiveness of a damper controller design on semi-active control. Control performance criteria are evaluated in the time and frequency domains in order to quantify the suspension effectiveness under bump and random road disturbance. The simulation results prove that the proposed strategy of the ANFIS inverse model with preview and optimization on MR damper produces a smoother and lower input voltage to the MR damper coil, ensuring extended damper life and lower power requirement, respectively. The compared results reveal that although the ANFIS inverse model with preview and optimization is able to improve ride comfort and vehicle stability over other mentioned strategies for semi-active suspension system or even passive suspension system.

Shehata Gad, Ahmed, El-Zoghby, Helmy, Oraby, Walid, Mohamed El-Demerdash, Samir

Improving Vehicle Rollover Resistance Using Fuzzy PID Controller of Active Anti-Roll Bar System

06-12-01-000312/20/2018

The active anti-roll bar (AARB) system in vehicles has recently become one of the research hotspots in the field of vehicle technology to improve the vehicle’s active safety. In most off-road vehicles, high ground clearance is required while keeping all wheels in contact with the ground in order to improve traction and maintain load distribution among the wheels. A problem however arises in some types of the off-road vehicles when the vehicle is operated at high speeds on smooth roads. In such condition, the combination of the vehicle’s center of gravity position, large suspension stroke, and soft spring construction creates a stability problem, which could make the vehicle liable to rollover. This article analyzes a comparison of stability performance between passive and active anti-roll bar systems to improve rolling resistance. For active systems, two control strategies will be investigated. The conventional Proportional Integral Derivative (PID) controller is firstly investigated and taken as a reference. Then a modified Proportional Integral Derivative (PID) controller with fuzzy technology is developed and compared to the reference one. A full-car model of 14-degrees of freedom (DOF) associated with the Pacejka tire model is used for the analysis and the simulation of the rollover prevention. The performances of the control strategies are compared and simulated using the MATLAB/Simulink program through a series of stability tests prepared by the National Highway Traffic Safety.

Khalil, Mohamed Mostafa, Atia, Mostafa R.A.

Influence of Intelligent Active Suspension System Controller Design Techniques on Vehicle Braking Characteristics

10-03-01-000312/4/2018

This article presents a comprehensive investigation for the interaction between vehicle ride vibration control and braking control using two degrees of freedom (2DOF) quarter vehicle model. A typical limited bandwidth active suspension system with nonlinear spring and damping characteristics of practical hydraulic and pneumatic components is controlled to regulate both suspension and tire forces and therefore provide the optimum ride comfort and braking performance of an anti-lock braking system (ABS). In order to design a suitable controller for this nonlinear integrated system, various control techniques are followed including state feedback tuned using Linear Quadratic Regulator (LQR), state feedback tuned using Genetic Algorithm (GA), Proportional Integral (PI) tuned genetically, and Fuzzy Logic Control (FLC). The ABS control system is designed to limit skid ratio below threshold of 15%. Several simulations are carried out in MATLAB environment to assess the benefits of the designed integrated controller including vehicle body vertical acceleration, dynamic tire load, stopping time, and distance. Furthermore, the proposed control techniques have been examined in terms of robustness, disturbance rejection, and noise attenuation. The obtained results revealed that the nonlinear assumptions of hydraulic and pneumatic suspension system components are notably influenced by the braking performance in terms of stopping time and distance which has successfully justified the aimed research topic. The effectiveness and robustness of the proposed controllers are discussed based on the simulation results which confirmed their significant improvements in both braking and ride characteristics.

Onsy, Ahmed Mahmoud, Sharaf, Alhossein Mostafa, Ashrey, Mahmoud Mohamed, Eldemerdash, Samir Mohamed

PSO-Fuzzy Gain Scheduling of PID Controllers for a Nonlinear Half-Vehicle Suspension System

06-12-01-000111/19/2018

The present article addresses the gain scheduling of proportional-integral-differential (PID) controllers using fuzzy set theory coupled with a metaheuristic optimization technique to control the vehicle nonlinear suspension system. The nonlinearities of the vehicle suspension system are due to the asymmetric piecewise dampers, quadratic tire stiffness, and the cubical spring stiffness. Conventional PID controller suffers from the low performance subject to modeling nonlinearities, while fuzzy logic controller (FLC), as a universal approximator, has the capacity to deal with the nonlinear, stochastic, and complex models. However, finding the optimal Mamdani FLC rules is still a challenging task in addition to a proper architecture of the membership functions (MFs). As a remedy to this drawback, particle swarm optimization (PSO) technique is employed in this article to improve the efficiency of the FLC-based PID controllers. The proposed nonlinear controller is suggestive of the decreased overshoot and reduced settling time for the heave and pitch motions of the half-vehicle model. The satisfactory performance of the controller, when tires are subject to random excitations, to reduce the peak magnitude is observable in a relatively less computational time.

Taghavifar, Hamid, Li, Bin

Considerations for ISO 26262 ASIL Hazard Classification

J2980_201804 (Historical)

4/28/2018

This SAE Recommended Practice presents a method and example results for determining the Automotive Safety Integrity Level (ASIL) for automotive motion control electrical and electronic (E/E) systems. The ASIL determination activity is required by ISO 26262-3:2011 [1], and it is intended that the process and results herein are consistent with ISO 26262:2011 [1]. The technical focus of this document is on vehicle motion control systems. It is limited to passenger cars weighing up to 3.5 metric tons. Furthermore, the scope of this recommended practice is limited to collision-related hazards associated with motion control systems. The recommended practice focused on motion control systems since the hazards they can create generally have higher ASIL ratings, as compared to the hazards non-motion control systems can create. Because of this, the Functional Safety Committee decided to give motion control systems a higher priority and focus exclusively on them in the SAE J2980 recommended practice. ISO 26262:2011 [1] has a wider scope than SAE J2980, covering other functions and accidents (not just motion control or collisions as in SAE J2980).

Functional Safety Committee

Dynamic Characteristics Analysis of an Ambulance with Hydraulically Interconnected Suspension System

2018-01-08154/3/2018

The vibration and instability experienced in an ambulance can lead to secondary injury to a patient and discourage a paramedic from emergency care. This paper presents a hydraulically interconnected suspension (HIS) system which can achieve enhanced cooperative control of roll, pitch and bounce motion modes to improve the ambulance's ride comfort and handling performance. A lumped-mass model integrated with a mechanical and hydraulic coupled system is developed by using free-body diagram and transfer matrix methods. The mechanical-fluid boundary condition in the double-acting cylinders is modelled as an external force on the mechanical system and a moving boundary on the fluid system. A special modal analysis method is employed to reveal the vibration characteristics of the ambulance with the HIS. A series of frequency analyses, including free vibration with identified eigenvalues and eigenvectors, vibration transmissibility and force vibration with stochastic road inputs, are performed to evaluate the vehicular performance between an ambulance with a conventional suspension and one with the HIS. The results show that the proposed HIS system is able to reduce the roll and pitch motion of sprung mass to improve the handling stability, meanwhile provide softer bounce stiffness to maintain the ride comfort. Furthermore, the vibration decay rate of sprung mass is significantly increased.

Tan, Bohuan, Wu, Yang, Zhang, Nong, Zhang, Bangji, Zheng, Minyi, Qi, Hengmin

Study on Fuzzy Control of MR into Semi - Active Suspension

2018-01-05614/3/2018

Suspension has a great influence on vehicle ride comfort and handling stability. How to improve the suspension performance has received more and more attention. To improve vehicle ride comfort, the magnetorheological damper (MRD) semi-active suspension is studied in this paper. Firstly, the dynamic calibration experiment of MRD was carried out so that the mechanical property curves was obtained. According to the experimental results, the Bouc-Wen model of MRD was identified and validated by Simulink Design Optimization. Secondly, The 1/4 of the vehicle vibration model can construct and calculate the vibration differential equations. The suspension of the simulation model can be constructed by the use of Matlab/Simulink software. Based on the established model, we can do an in-depth research on the active suspension control strategies under different road conditions and make related control strategies use the transfer function method. Then, taking the strong nonlinear of MRD itself into account, the fuzzy control algorithm is used to design the semi-active controller, which is realized by the single-chip microcomputer. Finally, in the Simulink, the magneto-rheological semi-active suspension is simulated and analyzed. We do the research on simulation of active suspension fuzzy control and get the simulation results for different road excitation and speeds. Simulation and experimental results show that the fuzzy control of the semi-active suspension can effectively improve the overall performance of the vehicle suspension. Compared with the passive suspension, the overall performance of the MRD semi-active suspension under the random pavement excitation is obviously improved. It provides the theoretical basis and numerical reference for the experimental study of the semi-active suspension.

Long, Haiyang

Control Research of Nonlinear Vehicle Suspension System Based on Road Estimation

2018-01-05534/3/2018

The control parameter of the semi-active suspension system varies with road profile; therefore, in this study a new algorithm based on cuckoo search (CS) optimization method and road estimation was proposed to investigate the characteristics of the nonlinear parameters and at the same time improve the riding comfort. Based on this, a seven degree of freedom full vehicle model was developed with nonlinear damper and spring. The sprung mass acceleration, pitch acceleration, and tire deflection could be selected as the objective functions, and the control current of semi active suspension was selected as optimization variable. A multi-object CS algorithm was utilized to obtain the optimal parameters under different road profiles, and a road estimation algorithm was used to identify the road level. Then the control parameters could be adjusted adaptively according to the level of the road. Furthermore, computer simulations were carried out to illustrate the performance of the proposed algorithm. Simulation results indicate that the proposed algorithm can easily identify the road level and adjust the control parameters adaptively. Moreover, the CS algorithm can provide better control performance compared to Particle Swarm Optimization (PSO).

Sun, Jinwei, Dong, Mingming, Qin, Yechen, Gu, Liang

Vibration Isolation Analysis and Optimization of Commercial Vehicle Cab Suspension System

2018-01-14054/3/2018

This paper starts with study on the transfer characteristics, and the vibration isolation of the cab suspension. Vibration models of cab suspension and complete vehicle were built through multi-body dynamics software ADAMS. Finite element and multi-body dynamics were collaborated into the analysis of the transfer characteristics, the response and the isolation feature of cab suspension based on the complete vehicle. To improve the vibration performance of the cab suspension, improvements and optimization design were proposed with genetic algorithm method. The analysis results show that there only limited effectiveness on coil spring. So the improvement plans were proposed to replace the coil spring with an air spring and setting transverse damper. According to the plans, the original cab suspension was modified. The piecewise function method was used in fitting the characteristic of the air spring. This method can directly reflect the stiffness characteristic of the air spring within its working area, thus is good for the design and optimization toward different working stage. Meanwhile, the damping characteristic curve of the cab suspension was also designed. Based on the optimization of the modified suspension, there was a great enhancement on the vibration isolation. The lateral and vertical vibration of the seat sliding was decreased a lot. The result shows the optimization and the modification were effective and correct.

Wang, Kaiyan, Gao, Feng

Energy-Harvesting Potential and Vehicle Dynamics Conflict Analysis under Harmonic and Random Road Excitations

2018-01-05684/3/2018

Energy has the worldwide concern since the World War. Recently, the energy harvesting technology has got more attraction in different fields and applications. Hence, in a world where energy becomes rare and expensive, even the small quantities are worth to be harvested where it can be exploited in different applications. Vehicle suspension is one of the vibration power dissipation sources in which the undesired vibration is dissipated into heat waste. Accordingly, the principal motivation of this study is exploitation the conflict between the potentially harvested power and vehicle dynamics in automotive suspension system induced by road irregularity. Therefore, in terms of RMS conflict diagrams, the conflict between the potential power and vehicle dynamics are sufficiently and comprehensively defined considering a vehicle speed of 20 m/s. The conflict analysis includes ride comfort (body acceleration), road handling (dynamic tire force) and potentially harvested power considering the influence of sprung and unsprung masses, stiffness rate, damping coefficient, tire stiffness, speed and road roughness. In this manner, a quarter suspension mathematical model is developed and built in Matlab/Simulink interface and uneven road profile is modeled for different road classes according to the ISO standard. Besides, a parametric analysis study is adopted to investigate the influence of the model parameters on the potentially harvested power. Then, the amount of the potential harvested power is quantified and presented for different driving conditions. The results are of interest for the researchers and vehicle manufacturers for further considerations during design and test preparation in the generative vehicle suspensions.

Abdelkareem, Mohamed A. A., Xu, Lin, Zou, Junyi, Ali, Mohamed Kamal Ahmed, Essa, F. A., Elagouz, Ahmed, Hassan, Mohamed A.

On Enhanced Fuzzy Sliding-Mode Controller and Its Chattering Suppression for Vehicle Semi-Active Suspension System

2018-01-14034/3/2018

This paper aims to present an enhanced fuzzy sliding-mode control scheme with variable rate reaching law for semi-active vehicle suspension systems, which can reduce chattering phenomena in high frequency compared with the sliding-mode controller with traditional exponent reaching law. First, an ideal-skyhook damping suspension system is taken as reference model; then the new control law is synthesized by employing the fuzzy logic control while considering the sliding-mode reaching segment characteristics, which can dynamically change the reaching rate to suppress chattering in closed-loop control systems; finally, simulation analysis is conducted under both random road and bump road surface, the results verified the effectiveness and feasibility of the proposed control scheme.

Pang, Hui, Yang, Junjie, Liang, Jun, Xu, Zeren

Optimized Proportional Integral Derivative Controller of Vehicle Active Suspension System Using Genetic Algorithm

2018-01-13994/3/2018

Proportional integral derivative (PID) control method is an effective, easy in implementation and famous control technique applied in several engineering systems. Also, Genetic Algorithm (GA) is a suitable approach for optimum searching problems in science, industrial and engineering applications. This paper presents the usage of GA for determining the optimal PID controller gains and their implementation in the active quarter-vehicle suspension system to achieve good ride comfort and vehicle stability levels. The GA is applied to solve a combined multi-objective (CMO) problem to tune PID controller gains of vehicle active suspension system for the first time. The active vehicle suspension system is modeled mathematically as a two degree-of-freedom mechanical system and simulated using Matlab/Simulink software. The performance of the proposed suspension system controlled using the optimized PID GA is compared to both controlled system using the classical PID (C PID) controller and the passive suspension systems. Systems performance criteria are evaluated in both time and frequency domains, in order to quantify the success of the proposed suspension system. The theoretical results reveal that the proposed optimized PID GA controller of the active vehicle suspension provides a vital enhancement of ride comfort and vehicle stability levels.

Metered, H., Abbas, W., Emam, A. S.

Method for Controlling Wheel End Loading through Pothole Event Using Continuously Variable Dampers

2017-01-14873/28/2017

A semi-active suspension system is designed to improve secondary ride by lowering damping levels while maintaining or enhancing primary ride control and vehicle handling. In order to provide optimized ride comfort, base damping levels are reduced. Reduced damping levels increase damaging loads through pothole events. The Road Load Mitigation (RLM) algorithm seeks to resolve the tradeoff of high damping levels required to control the vertical and horizontal spindle loads and the need for lower damping forces to improve secondary ride. As the base active damping forces are increased to control these loads, ride benefits or vehicle ride comfort is diminished. RLM looks at suspension velocity at all four corners independently to determine if a pothole signature is detected and requires compensation. Compensation is delivered quickly to reduce wheel drop into the pothole thereby reducing damaging loads. When detection occurs on the front axle, rear axle damping levels are increased just before the pothole event occurs.

Norton, Russ, Bulat, Ben, Mohamed, Ahmed

Development of Full Air Pneumatic Suspension Type for Commercial Vehicles

2017-01-14903/28/2017

The air suspension development and its applications have becoming increasingly relevant for commercial vehicles to provide dynamic ride comfort to driver and reduce the load impact onto driver and or cargo. This paper shows the analysis and application of an air suspension system for commercial tractor vehicles and its dynamic influence. A special focus was given to pneumatic actuation system, responsible for leveling and control of suspension´s stiffness under different conditions of usage, laden and unladed. The project was conducted starting with the vehicle dynamic performance analysis, evaluating the pneumatic suspension circuit modifications in order to obtain vehicle dynamic behavior improvement, ensuring directional stability under different maneuvering conditions. During the development quality tools were used, considering the possible failure modes and effects to guide the design changes in order to achieve the desired behavior, as well as virtual simulation tools (Adams) and rig test validations. Using data acquisition and vehicle test analysis, the improved dynamic results proposed were validated and considered as the final design solution.

Iombriller, Silvia Faria

Effect of Road Disturbance on the Ride Performance of Twin Accumulator and Semi-Active Suspension Systems

2017-01-04103/28/2017

Although active suspension improved vehicle ride comfort, their two main drawbacks are the required high component costs and energy input levels for active suspension. The semi-active and twin accumulator suspensions are proposed which addresses these two drawbacks. Ride performances for passive, twin accumulator and semi-active are examined theoretically using half vehicle model. The power consumed in rolling resistance and power dissipation in suspension for passive, twin accumulator and semi-active suspension systems are evaluated. The effect of road disturbance on the vehicle ride performance for twin accumulator and semi-active suspension systems is studied. The rolling resistance power losses are also investigated. The results showed that the optimum twin accumulator suspension system over all road roughness/speed conditions would have adaptable spring stiffness and damping coefficients which could be changed depending on the road conditions. Semi-active suspension systems already achieve part of this requirement by providing a limited choice of damper setting. The percentage of power dissipation in suspension relative to power consumed in rolling resistance for semi active suspension system is higher than that obtained for twin accumulator and passive system. The rolling resistance power losses are discussed.

Soliman, Aref M. A.

Optimization of Damper Top Mount Characteristics for Semi-Active Suspension System

2017-01-04123/28/2017

Semi-active suspension offers variety of damping force range which demands greater need to optimize the top mount to ensure multiple objectives of ride comfort, harshness and safety can be achieved. For this purpose, this paper proposes a numerical optimization procedure for improving the harshness performance of the vehicle through the adjustment of the damper top mount characteristics of the semi-active suspension system. The proposed optimization process employs a frequency dependent combined objective function based on ride comfort and harshness evaluation. A detailed and accurate damper top mount mathematical model is implemented inside a validated full vehicle model to provide a realistic simulation environment for the optimization study. The semi-active suspension system employs a Rule-Optimized Fuzzy-Logic controller. The ride comfort and harshness of the full vehicle are evaluated by analyzing the body acceleration in different frequency ranges. The dynamic stiffness of the damper top mount is used to describe the optimum damper top mount characteristics for different optimization case studies. The results show that, the proposed optimization routine enables - compensation of the harshness degradation in the semi-active suspension system by adjusting the characteristics of the damper top mount.

Çalışkan, Kemal, Henze, Roman, Küçükay, Ferit, Kaldas, Mina M.S.

Study on Controller of Electronically Controlled Air Suspension for Bus

2016-01-80339/27/2016

According to the vehicle’s driving conditions, electronically controlled air suspension (ECAS) systems can actively adjust the height of vehicle body, so that better ride comfort and handling stability will be achieved, which can’t be realized by traditional passive suspension. This paper presents a design and implementation of ECAS controller for vehicle. The controller is aimed at adjusting the static and dynamic height of the vehicle. To exactly track the height of the vehicle and satisfy the control demand of air suspension, a height sensor decoding circuit based on the inductance sensor is designed. Based on it, a new height control algorithm is adopted to achieve rapid and precise control of vehicle height. To verify the function of the designed controller and the proposed height control algorithm, an air spring loading test bench and an ECU-in-loop simulation test bench are respectively established.

Chen, Guoying

Development of Pneumatic Suspension Type Full Air for Commercial Vehicles

2016-36-00695/11/2016

The air suspension development and application has becoming increasingly applied also in commercial vehicles, offering to the driver more dynamic comfort as well as contributing to the reduction of impact loads on highways. Through this project pursuit show the analysis and application of an air suspension system for commercial tractor vehicles application. A special focus was given to pneumatic actuation system, responsible for leveling and control of suspension′s stiffness under different conditions of usage, laden and unladen. The project was conducted starting with the vehicle dynamic performance analysis, evaluating the pneumatic suspension circuit modifications in order to obtain the vehicle dynamic behavior improvement, ensuring directional stability under different maneuvering conditions. For entire development were also used quality tools, considering the possible failure modes and effects as well as virtual simulation tools (Adams) and bench validations. Through data acquisition and vehicular analysis, the better dynamic results proposed was validated and considered the final design solution.

Silva, Misael Neris da, Belli, Milton Monteverde, Iombriller, Silvia Faria, Knoll, Paulo Henrique, Conde, Ramon, Netto, Robson, Carraro, Eduardo

Study of Observer Considering Damper Force Dynamics for Semi Active Suspension Systems

2016-01-15534/5/2016

This paper reports that estimation accuracy of suspension stroke velocity is increased by considering the damping force delay characteristics to an observer. Thereby ride comfort is improved, using the simple and low-cost semi active suspension systems that use only three vertical acceleration sensors.

Yamamoto, Akihito, Tanaka, Wataru, Makino, Takafumi, Tanaka, Shunya, Tahara, Ken

Simulation Analysis on Controllability of Hydraulic Electrical Energy Regenerative Semi-Active Suspension

2016-01-04434/5/2016

A vehicular hydraulic electrical energy regenerative semi-active suspension(HEERSS) was presented, and its working principle and performance were analyzed. Firstly, configuration and working principle of the HEERSS were described; Secondly, kinetic equation of HEERSS was deduced, and a skyhook controller was designed for HEERSS. The traditional skyhook control strategy should be changed for the characteristic of HEERSS, because the damping force during extension stroke could be controlled, but not in compression stroke. Thirdly, the performance of HEERSS was compared with passive suspension(PS), traditional semi-active suspension(TSS). The simulation results indicated that the performance of HEERSS would be compromise between TSS and PS, but the HEERSS could harvest vibration energy which was advanced than TSS and PS.

Zhang, Han, Li, Gang, Wang, Yu, Gu, Yuchuan, Wang, Xiang, Guo, Xuexun

Dynamic Modeling and Simulation Analysis of Interconnected Air Suspension System

2016-01-04424/5/2016

Interconnected air suspension system can change a vehicle’s operation characteristics by exchanging gas between air springs. In this paper, we analyze the structure and working principle of interconnected air suspension based on thermodynamics and vehicle dynamics. Then air suspension’s mathematical model including interconnected characteristics is established to study gas exchange principle of air suspension system. Interconnected pipeline parameters and excitation phase differences’ influence on characteristics of air suspension system in whole vehicle are calculated and analyzed. Simulation results show that the stiffness of air suspension is reduced when air springs of the suspension system are interconnected, as well as it decreases gradually with the increase of interconnected pipeline diameter; the stiffness of air springs is minimum if the excitation phase difference between both sides of air springs is 180 degrees. In the condition of twist pavement (tires at diagonal positions are excited simultaneously), the interconnected air suspension can reduce dynamic load difference between left tire and right tire markedly, which can increase adhesive force between tire and road effectively. On the other hand, with the condition of double lane-change testing, the bigger the interconnected pipeline diameter is, the larger the roll angle of car body is. Meanwhile, the increasing pipeline diameter has no obvious influence on roll angle when it is over 10 mm.

Xu, Xing, Nannan, Zou

Design and Control of a Novel Geared Electromagnetic Active Suspension

2016-01-15544/5/2016

A novel geared electromagnetic active suspension is proposed in this paper. A pushing rod and a rocker are introduced to transfer the suspension vertical motion to the rotational motion of the motor. Comparing with the common ball-screw active suspension, it presents advantages of simple structure, easy manufacturing and module design. As the state variables of the suspension system cannot be all obtained for the sake of cost, taking the suspension deflection as the measurement, an output feedback LQR optimal controller is adopted, and it is concluded that the system can be stable with damping. Considering the nonlinearity of equivalent stiffness and unsprung mass caused by the system structure, parameter perturbation ranges are concluded through dynamic analysis, and robust H∞ control algorithm is proposed to realize the multi-objective optimization. The performance comparisons of both controllers mentioned above are carried out in the ADAMS/MATLAB co-simulation to reflect the influence of the nonlinearity of real time in practice. The results conclude that, in real system containing nonlinearity and parameter perturbations, the robust H∞ controller performs better in robustness of improving the ride comfort and handling stability.

Gu, Cheng, Chen, Xinbo, Yin, Jun

Design Aspects of a Novel Active and Energy Regenerative Suspension

2016-01-15474/5/2016

Traditional active suspension which is equipped with hydraulic actuator or pneumatic actuator features slow response and high power consumption. However, electromagnetic actuated active suspension benefits quick response and energy harvesting from vibration at the same time. To design a novel active and energy regenerative suspension (AERS) utilizing electromagnetic actuator, this paper investigates the benchmark cars available on the market and summaries the suspension features. Basing on the investigation, a design reference for AERS design is proposed. To determine the parameters of the actuator, a principle is proposed and the parameters of the actuator are designed accordingly. Compared the linear type and rotary type Permanent Magnet Synchronous Motor (PMSM), the rotary type is selected to construct the actuator of the AERS. Basing on the suspension structure of the design reference model and utilizing rotary type PMSM, a novel AERS structure is proposed. A prototype concept is thus designed and a scheme of test bench is shown. Further improvements of the actuator are discussed and through proper modifications, the actuator is expected to be applied on various suspension types.

Yin, Jun, Chen, Xinbo, Wu, Lixin, Li, Jianqin

A New Interval Inverse Analysis Method and Its Application in Vehicle Suspension Design

2016-01-02774/5/2016

Interval inverse problems can be defined as problems to estimate input through given output, where the input and output are interval numbers. Many problems in engineering can be formulated as inverse problems like vehicle suspension design. Interval metrics, instead of deterministic metrics, are used for the suspension design of a vehicle vibration model with five degrees of freedom. The vibration properties of a vehicle vibration model are described by reasonable intervals and the suspension interval parameters are to be solved. A new interval inverse analysis method, which is a combination of Chebyshev inclusion function and optimization algorithm such as multi-island genetic algorithm, is presented and used for the suspension design of a vehicle vibration model with six conflicting objective functions. The interval design of suspension using such an interval inverse analysis method is shown and validated, and some useful conclusions are reached.

Feng, Xingxing, Zhuo, Kaimin, Wu, Jinglai, Godara, Vikas, Zhang, Yunqing

Research on Inerter-Spring-Damper Semi-Active Suspension with Robust Control

2016-01-04284/5/2016

For coordinating the ride comfort and driving safety, the “inerter-spring-damper” (ISD) system is proposed in this paper, and the “spring-adjustable damper” is adapted to connect with ISD in series, then, a new type of semi-active suspension system is established. In order to verify the system rationality, the ISD semi-active suspension model and robust controller model are established respectively in the AMESim and MATLAB/Simulink environment, which is based on two degrees of freedom suspension model. Then, the co-simulation of ISD semi-active suspension with robust control is analyzed. Compared with the conventional ISD suspension, the results show that, the ISD semi-active suspension with robust control can significantly reduce the body vertical vibration, restrain tire resonance and enhance the tire grounding, that is, this system can coordinate the conflicts between vehicle ride comfort and driving safety.

Wang, Ruochen, Ding, Renkai, Ye, Qing

Performance Analysis of the Rule-Optimized Fuzzy-Logic Controller for Semi-Active Suspension

2016-01-04444/5/2016

This paper presents a performance analysis study for the Rule-Optimized controller of a semi-active suspension system. The Rule-Optimized controller is based on a Fuzzy Logic control scheme which offers new opportunities in the improvement of vehicle ride performance. An eleven degree of freedom full vehicle ride dynamics model is developed and validated through laboratory tests performed on a hydraulic four-poster shaker. An optimization process is applied to obtain the optimum Fuzzy Logic membership functions and the optimum rule-base of the semi-active suspension controller. The global optima of the cost function which considers the ride comfort and road holding performance of the full vehicle is determined through discrete optimization with Genetic Algorithm (GA). The performance analysis of the controller is performed by evaluating the Rule-Optimized controller performance under different driving conditions; including different road profiles, different vehicle speeds and different vehicle loadings. The results show that, the Fuzzy-Logic based Rule-Optimized controller for semi-active suspension provides significant improvements in both ride comfort and road holding performance of the vehicle under different operating conditions.

Çalışkan, Kemal, Kaldas, Mina M.S., Henze, Roman, Küçükay, Ferit

Implementation of Fuzzy Logic Control in Semiactive Suspension for a Vehicle Using MATLAB SIMULINK

2016-28-00352/1/2016

The design of the conventional passive suspension has always been a compromise between vehicle handling and comfort, which led to the development of the modern active and semi active suspension systems. Amongst these, semi-active suspension has been focus of research in recent years owing to its lesser complexity and less power consumption as compared to active suspension. Semi active suspension uses real time variation in damping coefficient which can be achieved by using various control strategies. It is observed from available literature that Skyhook (for better ride comfort), Groundhook (for better vehicle handling) and Hybrid are most widely used strategies. These strategies use ‘On-Off’ control strategy (i.e. two preset values of damping co-efficient) but a better control over damping coefficients can be achieved using Continuous Control strategy. This paper aims to implement Continuous control strategy using Fuzzy logic for the semi active suspension. For the analysis, Two degree of freedom Quarter car model is used which is excited by three road profiles namely Bump, Sine Wave and Swept Sine wave. Comparison is done on the basis of vehicle parameters: Body displacement, Wheel displacement, Suspension working space and Dynamic tire deflection. Also frequency response of system is analysed using Fast Fourier Transform. Simulation is done using MATLAB SIMULINK and results of ‘Continuous control strategy’ are compared with the results of ‘On-Off control strategy’ and ‘Passive suspension’. Continuous control strategy using Fuzzy Logic control was found to provide better overall performance with 22.1% reduction in body displacement, 11.66% reduction in dynamic tire deflection and 31.77% reduction in suspension working space. Also Fuzzy logic control retained its stability over whole frequency range.

Rasal, Shraddhesh, Jaganmohan, Jayanth, Agashe, Sohan, Wani, Kiran P

Considerations for ISO 26262 ASIL Hazard Classification

J2980_201505 (Historical)

5/7/2015

This SAE Recommended Practice presents a method and example results for determining the Automotive Safety Integrity Level (ASIL) for automotive electrical and electronic (E/E) systems. This activity is required by ISO 26262-3:2011 [1], and it is intended that the process and results herein are consistent with ISO 26262:2011 [1]. The technical focus of this document is on vehicle motion control systems. It is limited to passenger cars weighing up to 3.5 metric tons. Furthermore, the scope of this recommended practice is limited to collision-related hazards. ISO 26262:2011 [1] has a wider scope than SAE J2980, covering other functions and accidents (not just motion control or collisions as in SAE J2980).

Functional Safety Committee

A Comparative Study of Lumped Parameter Models for Assessing the Performance of Vehicle Suspension Systems

2015-01-06204/14/2015

Idealized mathematical models, also known as lumped parameter models (LPMs), are widely used in analyzing vehicles for ride comfort and driving attributes. However, the limitations of some of these LPMs are sometimes not apparent and a rigorous comparative study of common LPMs is necessary in ascertaining their suitability for various dynamic situations. In the present study, the mathematical descriptions of three common LPMs, viz. quarter, half and full car models, are systematically presented and solved for the appropriate response parameters such as body acceleration, body displacement, and, pitch and roll angles using representative passive suspension system properties. By carrying out a comparison of the three stated LPMs for hump-type road profiles, important quantitative insights, not previously reported in the literature, are generated into their behaviors so that their applications can be judicious and efficient.

Mahala, Manoj, Deb, Anindya, Chou, Clifford

A Semi-Active Suspension System Using Ride Control Based on Bi-linear Optimal Control Theory and Handling Control Considering Roll Feeling

2015-01-15014/14/2015

New ride control and handling control are developed, and installed in a system using only vehicle height sensor as dedicated sensors and pressure control type semi-active damper. Bi-linear optimal control is applied for controlling ride comfort control constructed observer which is inputted vehicle height sensor for calculating state quantity then used output of the observer. Behavior of vehicle was investigated by vehicle experiment and formalized to further improve the feeling of roll generated by handling control and devised and applied semi-active suspension control method which transiently realize the behavior. Proposed semi-active suspension system not only achieves damping performance as well as skyhook control, but also improves smooth ride comfort and handling performance including roll feeling. In this report, we describe aim, feature and effect of this system.

Hirao, Ryusuke, Kasuya, Kentaro, Ichimaru, Nobuyuki

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