Browse Topic: Chassis stiffness

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Multi-Mode Controller Design for Active Seat Suspension with Energy-Harvesting2020-01-10834/14/2020
In this paper, a multi-mode active seat suspension with a single actuator is proposed and built. A one-DOF seat suspension system is modelled based on a quarter car model of commercial vehicle with an actuator which is comprised of a DC motor and a gear reducer. Aiming at improving ride comfort and reducing energy consumption, a multi-mode controller is established. According to the seat vertical acceleration and suspension dynamic travel signals, control strategies switch between three modes: active drive mode, energy harvesting mode and plug breaking mode. In active drive mode, the DC motor works in driving state and its output torque which calculated by LQR algorithm is controlled by a current-loop controller; In energy harvesting mode, the DC motor works in generator state by which induced current can charge the power source, in this mode, the DC motor is considered as a damper which damping coefficient is decided by the charging current and controlled by Skyhook algorithm; In plug breaking mode, the DC motor works in the plug breaking state and its inverse voltage reaches to maximum to stop the suspension movement quickly. Simulations are carried out with random road and triangle block as the road excitation. The simulation results show that the multi-mode control strategy improves the ride comfort a lot compared with passive seat suspension, which effectively reduces energy consumption compared with fully active control strategy meanwhile.
Zhang, Zhenrui, Zhang, Yunqing, Xu, Peijun
The Effect of Friction on Ride Comfort Simulation and Suspension Optimization2020-01-07654/14/2020
The design of suspension affects the vehicle dynamics such as ride comfort and handling stability. Nonlinear characteristics and friction are important characteristics of suspension system, and the influence on vehicle dynamic performance cannot be ignored. Based on the seven-degree-of-freedom vehicle vibration nonlinear model with friction, the vibration response process of the vehicle and the influence of suspension friction on vehicle ride comfort and suspension action process were studied. The results show that friction will significantly affects the simulation of ride comfort and coincide with the function of the shock absorber. The suspension shock absorbers of vehicles were optimized with and without suspension friction. The results showed that the suspension tended to choose softer shock absorbers when there was friction. However, both of the two optimizations are able to improve the ride comfort of vehicles, and the simulation results were similar. At the same time, it was found that the better the dynamic performance of the vehicle model, the greater the influence of suspension friction on the simulation results of ride comfort.
Xuwang, Wang, Chen, Xiaoyu, Xu, Peijun, Zhang, Yunqing
Second-Order Sliding Mode Controller for Performance Analysis of Quarter Car Magnetorheological Suspension System2020-01-10054/14/2020
To achieve the simultaneous improvement in ride comfort of the passenger as well as the stability of the vehicle, a second-order sliding mode controller is proposed in this study. Super twisting algorithm attenuates the chattering effect present in the conventional sliding mode controller without affecting the stability of the system. The Lyapunov stability analysis is carried out to verify the stability of the controller. The effectiveness of the designed super twisting algorithm used second-order sliding mode controller is validated in a semiactive quarter car suspension with seat model. Modified Bouc-wen magnetorheological (MR) damper model is used as a semiactive damper and the voltage that has to be supplied to the magnetorheological damper is controlled by a super twisting algorithm and sliding mode controller. Continuous modulation filtering algorithm is adopted to convert the force signal of a controller into the equivalent voltage input to the MR damper. The entire system is modelled in Matlab/Simulink software and the simulations are carried out based on random road disturbances. The results show that there is a significant improvement in the second-order sliding mode controller semiactive MR suspension system compared with an uncontrolled passive suspension system. The robustness of the system is verified by analyzing it with mass uncertainties. Selected second-order sliding mode controller is validated by comparing it with a conventional sliding mode controller. The results depict a significant improvement in the performance of suspension system because of the application of the super twisting algorithm, second-order sliding mode controller.
Soosairaj, Arockia Suthan, K, Arunachalam
Crank-Lever Electromagnetic Damper (CLEMD) Design for Automobile Suspension System06-13-01-00022/4/2020
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
Study on the Quantitative Relationship between Static Stiffness and Modal Parameters of an Aluminum Space Frame10-04-02-00071/27/2020
In this article, the quantitative relationship between the static stiffness, lightweight factor, and modal parameters of an aluminum space frame was investigated. Modal theory calculation and finite element method were employed in the analysis. Fifty modal parameters were extracted from the finite element model of the frame to calculate the bending stiffness, torsional stiffness, and lightweight factor of the frame. The deviations of the bending stiffness, torsional stiffness, and lightweight factor obtained from the modal theory and the finite element theory were found to be 0.91%, 1.72%, and 1.71%, respectively. It indicates that these two methods have similar accuracy. It was confirmed that the sum of each order modal compliance could be used to calculate the static compliance of the aluminum space frame. The first-order bending mode was found to be the corresponding mode order, which made the largest contribution to the bending stiffness. This method is also applicable for identifying the first-order torsional mode. The results also show that such a modal identification method can avoid effectively the interference of local mode on the major body mode identification. The results obtained from finite element analysis and modal theory method were both verified by the experimental testing results. It proved that both of these two methods were effective in calculating the bending stiffness, torsional stiffness, and lightweight factor. As a comparison, the modal theory showed higher accuracy with lower deviation in the calculated parameters to the experimentally measured ones. The modal theory results of the bending stiffness, torsional stiffness, and lightweight factor were closer to the experimental results with deviations of 4.64%, 3.61%, and 3.64%, while they are 5.82%, 5.53%, and 5.29% for the finite element method, respectively. This article supplies important guidance for the lightweight design and target setting of aluminum space frames in the concept stage.
Wang, Zhenhu, Xia, Erli, Chen, Ziming, Xue, Zhigang, Li, Luoxing
Modelling and Simulation of Vehicle Suspension System with Variable Stiffness Using Quasi-Zero Stiffness Mechanism10-04-01-000312/2/2019
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
System Level Design of a Self-Stabilizing Two-Wheeler Suspension Concept2019-28-012710/11/2019
Two-wheeler represent one of the most used mode of transport in countries like India. The data from NCRB shows that most injuries to two-wheeler motorists are after being thrown off the vehicle. A self-stabilized combined with enclosure prevents serious injury in case of a skidding of the two-wheeler. The primary objective of the work is to create a suspension system for the enclosed self-balancing two-wheeler such that it can withstand the load of the vehicle itself and the extra payload. Ride comfort was primary objective of the work. The suspension system was modeled from the first principles, solved using MATLABTM SIMULINKTM and kinematics simulation was performed to learn the behavior of the system in MSC ADAMSTM. Dynamic simulations were also carried out to check if the forces were under permissible levels for overall design. The parameters considered for the work were hard-points, suspension stiffness and damping. With manual parameter iterations, suspension parameters were tuned for optimal suspension travel, load transmission and power transmission to ground. The work presents a concept for suspension system verified for kinematics and dynamic performance of the suspension.
Sankarasubramanian, Hariharan, Prabhahar, Dhurai
Simulation Analysis of a Dual-Purpose Intelligent Mobile Platform for Highway and Railway2019-01-14996/5/2019
Railways play a huge role in China's transportation industry. In order to ensure intelligence, advanced technology and high efficiency in functions such as railway inspection, rescue and transportation, a dual-purpose intelligent mobile platform for both roads and railways was developed. Due to the height limitation of this platform, resilient wheels and rubber dampers with short stroke are used as the suspension system for the rail chassis. Based on this special suspension form, the dynamic model of the whole platform is derived, and the simulation model of the whole platform is established in the simulation software. The effects of resilient wheels’ axial stiffness, radial stiffness and vertical stiffness, lateral stiffness of rubber dampers on the vertical and lateral stability of the platform were studied. It is found that the increase of the radial stiffness of the resilient wheels will deteriorate the vertical stability and lateral stability of the platform. The increase in the axial stiffness of the resilient wheels will deteriorate the vertical stability of the platform and the lateral stability will be improved. The increase of the vertical stiffness of the rubber dampers will deteriorate the vertical stability of the platform and have less influence on the lateral stability. The increase of the lateral stiffness of the rubber dampers will make the lateral stability of the platform better, but less on the vertical stability. This shows that the result is to prove that the platform can run smoothly on the rail and can optimize the stability within a certain range of stiffness.
Sun, Nan, Zhang, Wenming, Yang, Jue
A Novel Three Steps Composited Parameter Matching Method of an Electromagnetic Regenerative Suspension System2019-01-01734/2/2019
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
A Non-Contact Overload Identification Method Based on Vehicle Dynamics2019-01-04904/2/2019
The vehicle overload seriously jeopardizes traffic safety and affects traffic efficiency. At present, the static weighing station and weigh-in-motion station are both relatively fixed, so the detection efficiency is not high and the traffic efficiency is affected; the on-board dynamic weighing equipment is difficult to be popularized because of the problem of being deliberately damaged or not accepted by the purchaser. This paper proposes an efficient, accurate, non-contact vehicle overload identification method which can keep the road unimpeded. The method can detect the vehicle overload by the relative distance (as the characteristic distance) between the dynamic vehicle's marking line and the road surface. First, the dynamics model of the vehicle suspension is set up. Then, the dynamic characteristic distance of the traffic vehicle is detected from the image acquired by the calibrated camera based on computer vision and image recognition technology. The data error caused by the vehicle vibration can be reduced by the filter set up in this paper. Finally, the actual axle load of the vehicle can be obtained combined with the established model, which can be compared with the recorded standard data to detect overload vehicles. In this paper, the real vehicle test was carried out with Dong Feng Aeolus S30. The results show that the characteristic distance identification absolute error and relative error can respectively be controlled within 42.2mm and 3.18%, and the vehicle load identification precision can be 96.0%. The method above can effectively improve the efficiency of the overload identification and has certain guiding significance for maintaining the safety of intelligent transportation.
Zhou, Daolin, Tan, Gangfeng, Ding, Yiran, Yu, Shimin, Ma, Xiaofei, Wang, Shuai, Wang, Zhenyu
Application of a Preview Control with an MR Damper Model Using Genetic Algorithm in Semi-Active Automobile Suspension2019-01-50062/5/2019
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
INSIDE E-TRON19AUTP02_012/1/2019
Insights into the German approach to developing a premium-class EV. Audi has made its ambitious electromobility goals clear, saying it will offer 10 all-electric and 10 plug-in hybrid models by 2025, accounting for at least one-third of its sales. To help achieve this, the company carefully designed the all-new 2019 Audi e-tron luxury SUV to not alienate its core audience. As engineer Anno Mertens, Audi's product manager for electrification put it: “In the end, it's an Audi, it's not an electric car.” Audi's target for the e-tron (yes, the name is all lower case) is the same SUV buyer who might also have shopped for a Q7, Mertens said (the e-tron's wheelbase sits between the Q5 and Q7 in Audi's SUV lineup). To that end, early in the development process, Audi surveyed its customer base to learn just what kind of EV they would use. The questions included how many business trips they take and whether they live in detached homes or in multi-family dwellings.
Blanco, Sebastian
Modeling and Simulation of Steady State Handling Characteristics of Formula Vehicle with Antiroll Bars2019-26-00681/9/2019
Antiroll bar plays an important role in rollover stability of the vehicle. But not only does it limit the vehicle roll during cornering, but also alters the lateral load transfer between the tracks, which in turn affects the cornering performance of the vehicle. This paper deals with the design and mathematical modeling of antiroll bars to reduce the body roll of the vehicle from 1.5°/g to less than 1.0°/g. Rear bar uses a conventional torsion type bar but the front anti roll mechanism is an unconventional antiroll bar using a rotating double cantilever mechanism. Mathematical modeling is done for pushrod rod actuated antiroll mechanisms to simulate its non-linear roll rates. Antiroll bars for front and rear are designed for the calculated stiffness. Finite Element Analysis of antiroll bar and its components is done and the mechanism is tested on the vehicle. Steady state tire model parameters are generated by curve fitting tire testing data into pacejka coefficients. Then the vehicle mathematical model is built and simulated in multi-body simulation tool CarSim for various steady state and transient response tests like skidpad and double lane change. The effect of various antiroll bar configuration on front and rear to achieve the desired roll rate and handling characteristics of the vehicle. The use of Antiroll bar allowed to use softer spring rates and reduce the effective roll rate of the vehicle to 0.98 °/g. It also reduced the skidpad time by 1.4% and the autocross timings were reduced by 0.4 seconds per lap.
Gupta, Amit, Jadhav, Suraj, Mane, Ramchandra, Vora, Kamalkishore, Agrewale, Mohammad Rafiq
Enhanced Coil Spring Modeling in Passenger Car Suspension for Improved Target Setting Process06-12-01-000412/14/2018
The problem addressed in this work is how to formulate accurate targets for coil springs in passenger car suspensions to ensure that the required ride height and wheel rate are achieved. The issue arises because suspensions often tend to introduce significant spring deformations other than a purely axial compression. Although these effects are quite common, their influence on suspension performance is still not well understood. To this purpose, a new enhanced spring model is presented. The theory behind the model is explained and the relationship between spring and suspension performance discussed in detail. To validate formulations, a series of numerical simulations has been carried out demonstrating the model accuracy. Finally, a novel approach to spring target setting is proposed based on this advanced spring model.
Bianco, Roberto
Influence of Intelligent Active Suspension System Controller Design Techniques on Vehicle Braking Characteristics10-03-01-000312/4/2018
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
SHEAth-based Rollable LEnticular-Shaped and Low-Stiction (SHEARLESS) Composite BoomsTBMG-3339112/1/2018
NASA's Langley Research Center has developed the SHEARLESS composite boom with a final cross-section shape that is lenticular and is flexible enough to allow elastic flattening and subsequent coiling around a cylindrical reel/drum. The torsional stiffness of the structure is also greatly increased and becomes two orders of magnitude larger than that of the individual tape-spring components alone.
PSO-Fuzzy Gain Scheduling of PID Controllers for a Nonlinear Half-Vehicle Suspension System06-12-01-000111/19/2018
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
Selecting Gearhead Technology for Medical Imaging EquipmentTBMG-297467/1/2018
CT scanners have far greater accuracy than x-ray technology but place more demands on patients. Getting the high precision, three-dimensional images necessary for accurate diagnosis requires patients to lie still on a table moving through a magnetic field created by a large ring of magnets that rotates around them. Although the fundamentals of these designs are limited by the laws of physics and economics, over the years, medical equipment manufacturers have made great strides in refining system mechanics to maximize patient comfort. They have, for example, reduced the duration of a single rotation from hours to below 500 milliseconds, which has shortened sessions dramatically.
Improving Ride Comfort of a Heavy Truck2018-01-01354/3/2018
Ride comfort is simply defined as the vibration performance of the vehicle which is excited by road surface roughness, generally as the vehicle moves at specific constant velocity over the road profile. Ride comfort was an important index for heavy truck, due to long distance transfer and long time driving. In order to improve the ride comfort of a heavy truck, a detailed model, including flex frame, chassis suspension, cab suspension, powertrain, etc., was built and assembled by MSC.ADAMS software. Simulation and testing data were consistent very well, which showed the correctness of the model. The optimization of chassis and cab suspension including the stiffness of the leafspring, the damping of the shock absorber, etc. was carried out to improve the ride comfort of the vehicle. The ride comfort testing was carried out on the proving ground to verify the effectiveness the optimization results. The testing results shows that the ride comfort has been improved after tuning.
Jiang, Xuefeng, Yan, Feng, Chen, Wei, wang, Huawu
Dynamic Characteristics Analysis of an Ambulance with Hydraulically Interconnected Suspension System2018-01-08154/3/2018
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
Vibration Control of Active Vehicle Suspension System Using Optimized Fuzzy-PID2018-01-14024/3/2018
In this paper, a fuzzy-PID controller is applied in a half vehicle active suspension system to enhance vibration levels of vehicle chassis and passenger seat. The fuzzy-PID controller consists of fuzzy and PID connecting in a series manner, the fuzzy output is considered as the PID input. Genetic Algorithm (GA) is selected to tune controller parameters to obtain optimal values that minimize the objective function. The equations of motion of five-degrees-of-freedom active half-vehicle suspension system are derived and simulated using Matlab/Simulink software. Double bumps and random road excitations are used to study the performance of suspension systems including bounce and pitch motion. The performance of the active suspension system using optimized fuzzy-PID controller is compared with conventional passive to show the efficiency of the proposed active suspension system. The simulation results prove that the active suspension system controlled using the optimized fuzzy-PID controller can offer significant improvements of ride comfort and vehicle stability.
El-taweel, H., Abd elhafiz, Mohamed M., Metered, H.
An ATV Model for CarSim2018-01-05734/3/2018
This paper presents the development of a CarSim model of an All-Terrain Vehicle (ATV) that can be used to predict the handling and stability characteristic of the vehicle. The inertia and suspension characteristics of a subject ATV are measured and a model of the ATV is built in CarSim based on the measurements. A simplified suspension model is developed to convert the suspension compliance measurements into parameters suitable to a CarSim model. Procedures used to apply vehicle mass, inertia and suspension kinematics data in CarSim are also shown. The model is evaluated using predictions of vehicle response during a constant radius circle test. The simulation results of the maneuver are compared with the field test results shown in a recent CPSC report on ATV’s. Similar cornering characteristics are found in both results. Modifications are made to the model to study how changes to the ATV affect performance. The model developed provides a sound baseline for more comprehensive ATV models that contain more accurate tire and damping models based on actual tire and shock absorber measurements.
Jia, Bingrui, Guenther, Dennis, Heydinger, Gary, Zagorski, Scott, Sidhu, Anmol
Energy-Harvesting Potential and Vehicle Dynamics Conflict Analysis under Harmonic and Random Road Excitations2018-01-05684/3/2018
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.
Optimized Proportional Integral Derivative Controller of Vehicle Active Suspension System Using Genetic Algorithm2018-01-13994/3/2018
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.
Rubber Suspension Bushing Model Identified by General Design Parameters for Initial Design Phase2018-01-06934/3/2018
This article proposes a rubber suspension bushing model considering amplitude dependence as a useful tool at the initial design phase. The purpose of this study is not to express physical phenomena accurately and in detail and to explore the truth academically, but to provide a useful design method for initial design phase. Experiments were carried out to verify several dynamic characteristics of rubber bushings under vibration up to a frequency of 100 Hz, which is an important frequency range when designing ride comfort performance. When dynamic characteristic theory and the geometrical properties of the force-displacement characteristic curve were considered using these dynamic characteristics as assumptions, an equation was derived that is capable of calculating the dynamic stiffness under an arbitrary amplitude by identifying only two general design parameters (dynamic stiffness and loss factor) under a reference amplitude. The rubber suspension bushing model was then constructed by transforming this equation. Two verifications were carried out to confirm that the model is capable of reproducing measured bushing characteristics. Previous models consist of a large amplitude stiffness component and an artificially created friction component, and must be identified using three unknown values. In contrast, the proposed model only consists of a function derived theoretically from the above assumptions. Consequently, this model can be identified using the two unknown values described above, which are general design parameters used by suspension engineers in everyday design work.
Horiuchi, Kentaro, Sakaguchi, Shinichi
Chevy unveils larger, lighter 2019 Silverado at Detroit auto show18AUTP02_122/1/2018
With chief rival Ford setting sales records with its F-Series pickups and FCA's Ram brand prepared to unveil an all-new Ram light-duty pickup at the 2018 Detroit auto show, Chevrolet answered by unveiling on the eve of the Detroit show the 2019 Silverado 1500 that Mark Reuss, General Motors executive vice president of Global Product Development, confirmed is “all-new from the ground up.” That means totally new sheetmetal that telegraphs the Silverado's larger footprint and taller profile, but also includes a new frame that contributes to the 2019 Silverado's claimed weight reduction of up to 450 lb (204 kg) compared with a V8-powered crew cab model from the existing Silverado lineup. Still aiming to parry Ford's ground-breaking use of aluminum for the F-Series' body panels-as well as its cargo bed-Reuss said the new Silverado's weight reduction is the “direct result of our expertise in mixed materials and manufacturing technology.”
Visnic, Bill
Degradation of Vehicle Noise and Vibration by Ageing of Elastomers2017-01-03923/28/2017
The vehicle elastomeric components such as engine mounts could be aged and degraded by environmental loads such as thermal and mechanical loads during long term usage by customers. These make the degradation of vehicle driving performance comparing with a new condition. In this study, the main cause of NVH (Noise, Vibration and Harshness) degradation of a used vehicle was analyzed. It could be identified by the analysis of vibration insulating property changes of elastomeric components. The properties changes of aged engine mounts were analyzed and compared with initial properties. The accelerated laboratory ageing test mode was developed for simulating the degradation of engine mounts by thermal load analysis. Moreover, parametric studies were carried out to identify the robust engineering design technique. The engineering design parameters of elastomers such as volume, thickness and mechanical loading types were identified to improve the degradation phenomenon.
Sung, Dae-Un, Busfield, James, Ryu, Yong Hyun
Mount Model Dependent on Amplitude and Frequency for Automotive Powertrain Mounting System2017-01-04053/28/2017
Three constitutive models which capture the amplitude and frequency dependency of filled elastomers are implemented for the conventional engine mounts of automotive powertrain mounting system (PMS). Firstly, a multibody dynamic model of a light duty truck is proposed, which includes 6 degrees of freedom (DOFs) for the PMS. Secondly, Three constitutive models for filled elastomers are implemented for the engine mounts of the PMS, including: (1) Model 1: Kelvin-Voigt model; (2) Model 2: Fractional derivative Kelvin-Voigt model combined with Berg’s friction; (3) Model 3: Generalized elastic viscoelastic elastoplastic model. The nonlinear behaviors of dynamic stiffness and damping of the mounts are investigated. Thirdly, simulations of engine vibration dynamics are presented and compared with these models and the differences between common Kelvin-Voigt model and other constitutive models are observed and analyzed.
Lv, Tianqi, Feng, Xingxing, Xu, Peijun, Zhang, Yunqing
An Improved PID Controller Based on Particle Swarm Optimization for Active Control Engine Mount2017-01-10563/28/2017
Manufacturers have been encouraged to accommodate advanced downsizing technologies such as the Variable Displacement Engine (VDE) to satisfy commercial demands of comfort and stringent fuel economy. Particularly, Active control engine mounts (ACMs) notably contribute to ensuring superior effectiveness in vibration attenuation. This paper incorporates a PID controller into the active control engine mount system to attenuate the transmitted force to the body. Furthermore, integrated time absolute error (ITAE) of the transmitted force is introduced to serve as the control goal for searching better PID parameters. Then the particle swarm optimization (PSO) algorithm is adopted for the first time to optimize the PID parameters in the ACM system. Simulation results are presented for searching optimal PID parameters. In the end, experimental validation is conducted to verify the optimized PID controller. The study demonstrates that the improved PID controller reveals effective vibration isolation performance.
Guo, Rong, Wei, Xiao-Kang, Gao, Jun
Methodology to Study the Effect of Variation of Suspension Characteristics on Body Durability2017-01-03483/28/2017
In an automobile, road loads due to tire-road interaction are transferred to vehicle body through suspension. This makes suspension a critical component from the body durability perspective. During vehicle design and development, optimization of suspension parameters to suit ride and handling performance is a continuous and iterative process. These changes on suspension can affect vehicle body durability performance. This paper tries to establish a process to evaluate the effect of changes in suspension parameters on body durability, thus helping in understanding the impact of these changes. The process starts with virtual model building in Multi Body Dynamics software. The base line model is correlated with testing using fatigue at some critical locations on Body in White (BIW). Once correlated, Design of Experiments (DOE) approach is used on suspension parameters like spring properties, damper properties etcetera to identify critical parameters that will affect the magnitude of loads on the body-suspension attachment points. These loads are further used to evaluate effect on durability of the body using Finite Element Method (FEM) approach.
Shankar, Mani, Sri Harsha, I V N, Sunil, K V, Ramachandran, Ramsai
Simulating the Mobility of Wheeled Ground Vehicles with Mercury2017-01-02733/28/2017
Mercury is a high-fidelity, physics-based object-oriented software for conducting simulations of vehicle performance evaluations for requirements and engineering metrics. Integrating cutting-edge, massively parallel modeling techniques for soft, cohesive and dry granular soil that will integrate state-of-the-art soil simulation with high-fidelity multi-body dynamics and powertrain modeling to provide a comprehensive mobility simulator for ground vehicles. The Mercury implements the Chrono::Vehicle dynamics library for vehicle dynamics, which provides multi-body dynamic simulation of wheeled and tracked vehicles. The powertrain is modeled using the Powertrain Analysis Computational Environment (PACE), a behavior-based powertrain analysis based on the U.S. Department of Energy’s Autonomie software. Vehicle -terrain interaction (VTI) is simulated with the Ground Contact Element (GCE), which provides forces to the Chrono-vehicle solver. The driver model implements an array of tests for evaluating vehicle mobility performance. With these physics submodules, Mercury can simulate a variety of performance tests such as ride quality, maximum shock, sand slope climbing, VCI1, acceleration tests, and many others. Additionally, the open, modular framework of Mercury makes the extension of the software to new tests and physics domains fast and easy.
Goodin, Chris, Priddy, Jody, Lynch, Larry, Mange, Jeremy, Pace, Sara, Skorupa, Thomas, Kedziorek, Daniel
Simulation Modeling on Dynamic Stiffness of Leaf Spring Based on Three-link Model2017-01-04213/28/2017
The leaf spring has significant hysteresis characteristics due to the interleaf friction. The traditional three-link model could not simulate the hysteresis characteristics at all. According to the dynamic load test results one can find that the dynamic stiffness of leaf spring has a nonlinear relationship with the travel distance and the load frequency has a tiny influence on it. Based on the traditional three-link model, this paper proposed a simulation modeling method by introducing torsional friction on the revolute joints. The key parameters including torsional spring stiffness, friction torque preload, stiction transition velocity and max stiction deformation are optimized by combining the ADAMS and OPTIMUS. The comparison analysis between the simulation and test results of front and rear leaf springs have revealed that the maximum average errors are 4.84% and 6.41%, respectively. The proposed simulation modeling method of leaf spring lays a foundation for the high efficiency and precision modeling of vehicles on ride comfort.
Liu, Xiang, Zhao, Jing, Chen, Wei, Chen, Ying
Basic Characteristics of Adaptive Suspensions of Vehicles with New Principle of Operation2017-01-04043/28/2017
Currently, a group of scientists consisting of six doctors of technical sciences, professors of South Ural State University (Chelyabinsk, Russia) has completed a cycle of scientific research for creation of adaptive suspensions of vehicles. We have developed design solutions of the suspensions. These solutions allow us to adjust the performance of the suspensions directly during movement of a vehicle, depending on road conditions - either in automatic mode or in manual mode. We have developed, researched, designed, manufactured, and tested experimentally the following main components of the adaptive suspensions of vehicles: 1) blocked adaptive dampers and 2) elastic elements with nonlinear characteristic and with improved performance. Applications of our developed designs are as follows: suspensions of almost all vehicles (trucks, cars, buses and so on), except "waterfowl", and high-speed tracked vehicles, including special purpose and trailers, aircraft for various purposes, rail transport, particularly high-speed one, motorcycles, etc. Application of our designs will allow harmonizing by optimal way the various performance requirements for vehicles, which are often contradictory: requirements on smoothness and comfort ride, rapidity, stability and control, traffic safety, values of dynamic loads acting on components and units of vehicles, stabilization of their movements and body position. In this paper we analyze the main features of the performance of our designs of adaptive shock absorbers and elastic elements, results of our theoretical and experimental studies.
Dubrovskiy, Anatoliy, Aliukov, Sergei, Dubrovskiy, Sergei, Alyukov, Alexander
Servo Couplings for High-Tech SystemsTBMG-264322/1/2017
Couplings are a critical part of system performance in high-tech applications, yet they are often one of the last components to be specified. Selecting the proper coupling ensures the equipment will meet performance requirements and have a long, trouble-free life. Poor coupling selection can lead to high maintenance costs, frequent downtime, and imprecise positioning.
Integrated Approach for Development of Air Suspension System for a SUV Category Vehicle Using Analytical and Experimental Tools2017-26-03401/10/2017
Air suspension systems had been introduced in automobiles since 1950s. These systems are being explored to improve the ride comfort, handling stability and also serve as a medium for better cargo protection. These system are well developed for buses and high end passenger sedans, also have feasibility for adapting for wide range of configurations of suspension system and axle. Passenger cars and Sports Utility Vehicle (SUV) pickup category of vehicle offers different challenges such as space availability, spring selection and characterization that need to be addressed for successful implementation of air suspension in these category vehicles. This work defines methodology to implement air suspension system in SUV Pickup category vehicle. Paper work includes concept study, mathematical co-relation, and prediction of air spring characteristics and integration of experimental and analytical tool for development of air suspension system.
Bire, Sarang, Pawar, Prashant R, Saraf, M
Critique of Torsional Vibration Damper (TVD) Design for Powertrain NVH2017-26-02171/10/2017
Crank train torsional vibration is an important aspect for design and development of Powertrain for NVH refinement and durability. Crank train torsional vibration parameters like angular acceleration of flywheel or twist, depends upon various design parameters like geometry of crankshaft, mass of flywheel, stiffness of clutch, mass of pulley etc. It also depends upon engine operating conditions like engine speed, engine load, combustion peak pressure and combustion pressure variation etc. Most of these parameters are decided by engine power, torque, engine architecture and packaging constraints. Addition of torsional vibration damper (TVD), which works on the principle of tuned dynamic absorber, is commonly deployed design solution to control the torsional vibrations as well as stresses (to improve durability of crank train) induced in crank train assembly at specified modal frequency. This paper is critique study, which emphasizes on importance of accurate tuning of TVD frequency to make it work for NVH & durability improvement rather than deterioration. It also emphasizes whether crank train really need TVD or not. As its principle of working calls for, it needs to be tuned at right frequency to reduce the torsional vibration peak/twist at particular frequency. Any deviation in tuning of TVD frequency will force it to act as additional mass rather than tuned absorber. This will lead to the lowering of torsional frequency of crank train assembly and can shift the crank train assembly mode to critical operating frequency range of engine.
Yadav, Arvind Kumar, Birari, Mayur, Bijwe, Vilas, Billade, Dayanand
Finite Element and Experimental Analysis of the Torsional Stiffness of a Chassis of a Baja SAE Prototype2016-36-012410/25/2016
The torsional stiffness of a chassis is one of the most important properties of a vehicle’s structure, once a low torsional stiffness has many negative effects, especially in handling characteristics. For the first time, the torsional stiffness was considered on the design of a Baja SAE prototype of the team from UNESP - FEG, “Equipe Piratas do Vale”. In this work, a finite element analysis is first performed in order to evaluate the torsional stiffness of this prototype, called MB1114. Then, an experimental evaluation of this parameter is executed, detailing the post-processing of the results, such as the hysteresis effect and uncertainty analysis. It also shows that it is possible to measure the torsional stiffness of chassis with a low experimental uncertainty without spending too much. The test rig used is simple to be produced and can be easily stocked. Those features are important for Baja and Formula SAE teams. After performing the finite element analysis, a result 13.4% higher than the measured value was reached. This difference is believed to be due to the finite element model inaccuracy, in other words, it came from the fact that is not possible to simulate every detail present on the real model.
Motta Barbosa, Luís Felipe Ferreira, Tomazini, José Elias, Martins, Marcelo Sampaio, Querido Moreira, Lucas Reis Rangel, Tokuue Hori, Marcos Yukio, Silva, Luís Felipe Santos
Formula SAE Chassis Design to Improve Suspension Tuning2016-36-023910/25/2016
In many vehicle motorsport categories, the one of the most important factors that lead a team to the victory is the suspension setup. Parameters like roll stiffness and camber changing are essential to the vehicle behavior during a driving situation. To handle these variables, features like suspension hardpoints arrangement, pivot points position and spring stiffness can be settled. However a setup only will perform a desirable effect if the chosen configuration does not change. Ideally, to make it possible, every component that holds suspension loads (suspension members, mounting plates and chassis) would have to be infinitely rigid. Even though it is not achievable, the existing deformation can be small enough to be negligible when compared with suspension displacement. In order to reach this target, this paper introduce a spring modeling and a Finite Element multibody modeling process of a Formula SAE prototype’s suspension and chassis. These models allows the investigation of chassis elasticity effect on suspension’s operation properties. Furthermore, the data obtained are essential to set the chassis torsional stiffness target and the final suspension’s pick-up points geometries, avoiding an oversized design. To validate the model a bench test was performed to obtain a correlation between the real case and Finite Element model, which reached a value of 98,2% and allowed the removal of excessive torsional stiffness and a mass reduction of 9%. In addition, the study allowed to identify a critical stress point and a reinforcement was added.
Bortoluzzi, Lucas Iensen, Schommer, Adriano, Martins, Mario, Buenos, Alexandre Aparecido
Adaptive Suspension of Vehicles with Wide Range of Control2016-01-80329/27/2016
In this paper we consider a new design of adaptive suspension systems of vehicles with better technical characteristics and functional abilities in comparison with existing designs. We have developed the following main suspension components of vehicles: a lockable adaptive shock absorber with a wide range of control performance, implementing "lockout" mode by means of blocking adaptive shock absorber, and an elastic element with progressive non-linear characteristic and automatic optimization of localization of work areas. Advantages of our developments in the vehicle suspensions are the following: 1) when the vehicle is in a wide range of speeds in a so-called "comfort zone", we have managed, by applying the non-linear elastic element, to reduce significantly the stiffness of the elastic suspension elements in compare with the regular structures - at least in two times. This means that comfort, smooth motion, high performance the vehicle when driving over bumps are improved in times. Dynamic loads on the crew, passengers, equipment, components and assemblies of the vehicles are reduced in a big extent; 2) stiffness of the non-linear elastic element beyond "comfort zone" is increasing: at first - more than three times as compared with regular elastic elements; and further increasing of the stiffness of the elastic elements is more than 60 times. We have installed the developed design of the suspension on the Russian cars VAZ "LADA-GRANTA" and "LADA-KALINA." In this paper we describe some results of experimental studies. The experimental results confirmed the validity of the theoretical propositions.
Dubrovskiy, Anatoliy, Aliukov, Sergei, Keller, Andrei, Dubrovskiy, Sergei, Alyukov, Alexander
Effect of Cab Suspension Configuration and Location on Tractor Semi-Trailer Driver Comfort2016-01-90189/16/2016
It is well known that the ride quality of trucks is much harsher than that of automobiles. Additionally, truck drivers typically drive trucks for much longer duration than automobile drivers. These two factors contribute to the fatigue that a truck driver typically experiences during long haul deliveries. Fatigue reduces driver alertness and increases reaction times, increasing the possibility of an accident. One may conclude that better ride quality contributes to safer operation. The secondary suspensions of a tractor have been an area of particular interest because of the considerable ride comfort improvements they provide. A gap exists in the current engineering domain of an easily configurable high fidelity low computational cost simulation tool to analyze the ride of a tractor semi-trailer. For a preliminary design study, a 15 d.o.f. model of the tractor semi-trailer was developed to simulate in the Matlab/Simulink environment. The developed model incorporates the effects of frame beaming. The contributions of the different modes of vibration to the ride comfort were analyzed. It is shown in this work that the ride at the driver seat can be significantly improved by relocating the cab mounts near the nodes of the first mode of bending of the tractor frame and by employing a full cab suspension. The developed simulation tool was used to quantify the improvements in the driver ride comfort.
Roy, Judhajit, Law, E. Harry
Servo-Flap Rotor Design for High Density Altitude OperationF-0072-2016-114005/17/2016
It is a unique and challenging task to design a servo-flap main rotor control system that is operational at high density altitudes. At such elevated altitudes, both the main rotor blade and the servo-flap aerodynamics strongly affect helicopter operation. The changes in flap lift alter the aerodynamic pitching moment with respect to the main rotor blade, which results in an interesting blade feathering motion and its required control input. The servo-flap rotor design does not require any pitch link control spring rate. In addition, the blade torsional stiffness and tennis racket moment due to centrifugal force, are almost un-changed by the high altitude air density. The helicopter’s high altitude operation can be achieved through a unique combination of rotor design, servo-flap control, and installed engine power. The servo-flap rotor has a unique ability that allows flap adjustment every time the pilot alters the operating aircraft density altitude by 5,000 feet. This allows the aircraft to retain the same flight characteristics at any altitude that it had at sea level. This unique feature makes the servo-flap rotor one of the best candidates for high altitude flight operation. A new and improved design feature is proposed in this paper. The high altitude actuator control system provides a steady null offset that is simultaneously applied to all flaps. The new actuator signal is introduced in parallel with the basic servo-flap control system. The new hardware is designed to be used within the present control system. This design opens up the autorotation flap control range without impacting servo-flap flight control operation and safety.
Wei, Fu-Shang
Results Of A Parametric Design Study To Adapt The Structural Properties And Strain Distribution Of Active Twist BladesF-0072-2016-115425/17/2016
Rotor Blades, especially active twist blades, have been investigated by DLR (German Aerospace Center) for many years and the feasibility of this technology was shown in several projects. (1-8) However, many relevant features must be taken into account within the design process. The most challenging aspect is the proper tuning of the structure to integrate the fragile actuators, because they have to sustain a variety of loads, while still providing the expected performance. Further different constraints on bending and torsional stiffness or axes positions of the rotor blade exist. At DLR a tool called SaMaRA (Structural Modelling and Rotor Analysis) was developed. It's a parametric finite element model to meet these partially conflicting requirements as part of a structural optimization framework. The proposed paper provides an overview of the adaption of structural properties and shows representative results for active twist blades.
Kalow, Steffen, Opitz, Steffen, Riemenschneider, Johannes, Hoffmann, Frauke
The Research of Vehicle Dynamics Modeling Method Based on the Characteristics of Suspension and Steering Systems2016-01-04704/5/2016
This paper presents the relationship between suspension and steering systems and wheels, and proposes the vehicle dynamics modeling method. A vehicle dynamics model combined with the suspension K&C test data of a concrete vehicle was built based on the method. The simulation results show that the method is correct and feasible, and the dynamics model performed characteristics of the suspension and steering systems with high precision can be used for the followup simulation and optimization.
Chen, Wei, Sun, Zhe, Zheng, Jun, Pan, Liang, Yi, Xurong
Lateral Stability and Improvement for a Prototype Pickup Truck Vehicle Using Multi-Body Dynamics Simulation Tools2016-01-16284/5/2016
Lateral Stability is an important attribute which must be accounted for in the pick-up truck segment vehicles. If designed in an improper way, undesirable effects such as oversteer or tail sway may occur. Excessive yaw rate magnitudes, or tail sway, can reduce the confidence of the driver during severe lane change events. The concept architecture of the vehicle plays an important role in how stable the vehicle will be. High yaw rate or tail sway during limit cornering was reported during prototype vehicle evaluations. The tested vehicle configuration incorporated a double wish bone front suspension with an antiroll bar and a rear solid axle suspension with leaf springs and an antiroll bar. The feedback was critically analysed using computer simulations of the condition found in on track testing. Since the vehicle was still with the validation team, quick solution was necessary. This paper discusses the process which resulted in improved vehicle performance. The modelling and analysis of the vehicle for lateral dynamics is discussed as is the correlation of the simulation results with real world test data. The analysis of the influence of various parameters on the lateral dynamics using the MSC.ADAMS/CAR software is also presented. Simulations with different spring stiffnesses were carried out on the in-house existing suspension. Different antiroll bar configurations were studied for their effect on vehicle yaw stability thus avoiding new system development time and cost. The influence of the above parameters was studied using maneuvers which involved steady-state cornering as well as single lane change and double lance change tests. The results of the simulations indicated that the shock-absorber needed higher damping levels and the antiroll bars were increased in size in order to improve the dynamic performance of the pickup truck. The new suspension tuning level felt improved compared to the existing configuration.
Pahwa, Gurdeep Singh, Anthonysamy, Baskar, Shah, Karan
Dynamic Modeling and Simulation Analysis of Interconnected Air Suspension System2016-01-04424/5/2016
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
Optimization of Suspension System of Self-Dumping Truck Using TOPSIS-based Taguchi Method Coupled with Entropy Measurement2016-01-13854/5/2016
This study presents a hybrid optimization approach of TOPSIS-based Taguchi method and entropy measurement for the determination of the optimal suspension parameters to achieve an enhanced compromise among ride comfort, road friendliness which means the extent of damage exerted on the road by the vehicles, and handling stabilities of a self-dumping truck. Firstly, the full multi-body dynamic vehicle model is developed using software ADAMS/Car and the vehicle model is then validated through ride comfort road tests. The performance criterion for ride comfort evaluation is identified as root mean square (RMS) value of frequency weighted acceleration of cab floor, while the road damage coefficient is used for the evaluation of the road-friendliness of a whole vehicle. The lateral acceleration and roll angle of cab were defined as evaluation indices for handling stability performance. The spring stiffness and shock absorber damping of the front suspension, spring stiffness of the rear suspension, torsional stiffness of the front and rear anti-roll bar are taken as the design variables, which are considered at three levels. A L18 orthogonal array is applied to implement the simulations, and the TOPSIS is thus used to integrate all determined performance criteria of ride comfort, road friendliness and handling stability into a single performance index. Meanwhile, the weights of the quality characteristics are determined by employing the entropy measurement method. Furthermore, the best factor levels are identified according to the Taguchi method principles for single response optimization. Finally, the optimal combination of suspension parameters is confirmed to illustrate the effectiveness of the proposed hybrid optimization method.
Jiang, Rongchao, Wang, Dengfeng
Design and Control of a Novel Geared Electromagnetic Active Suspension2016-01-15544/5/2016
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
Regenerative Shock Absorbers and the Role of the Motion Rectifier2016-01-15524/5/2016
The development of suspension systems has seen substantial improvements in the last years due to the use of variable dampers. Furthermore, the efficiency increase in the subsystems within the automotive chassis has led to the use of regenerative solutions, in which electric machines can be employed as generators to recover part of the energy otherwise dissipated. However, the harvesting capability of regenerative suspensions is often limited by friction and inertial phenomena. The former ones waste mechanical energy into heat, while the latter ones hamper the shock absorption by locking the suspension when subject to dynamic excitation. Besides a suitable design and sizing of components, recent research works highlight the use of the so-called motion rectifier to improve energy recovery by constraining the motion of the electric motor to a single sense of rotation. This strategy can potentially reduce inertial issues related to zero-speed crossing and motion inversion, thus leading to better conversion efficiency. Although results in literature indicate favorable damping characteristics of the shock absorbers equipped with this device, the real advantages introduced by the motion rectifier are yet to be quantified. In this context, the present paper aims to analyze hydraulic regenerative shock absorbers with the particular goal of putting in evidence the benefits and implications introduced by the use of the motion rectifier. Quantitative results from accurate modeling and simulation highlight the capabilities of the device in terms of harvested power, conversion efficiency, comfort and road holding.
Galluzzi, Renato, Tonoli, Andrea, Amati, Nicola, Curcuruto, Gabriele, Conti, Piero, Greco, Giordano, Nepote, Andrea
A New Interval Inverse Analysis Method and Its Application in Vehicle Suspension Design2016-01-02774/5/2016
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 Control2016-01-04284/5/2016
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
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