Browse Topic: Suspension systems

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Nitrogen Absorption/Desorption (Gas Dissolution) in Aircraft Shock AbsorbersAIR6942 (Current)11/26/2025
This document outlines the current state of the art in the understanding of gas in solution in shock absorber oils in unseperated shock absorbers. A literature review, overview of Henry's law, Henry's law coefficients for known gas and oil couples, in-service operational problems, lessons learned, and potential future work will be discussed in the document.
A-5B Gears, Struts and Couplings CommitteeNEW
Experimental Assessment of a Controlled Slippage Magnetorheological Automotive Active Suspension for Ride Comfort10-06-04-00248/23/2022
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
testprint9SAE-PP-010034/27/2022
testprint9
Mutagaana, Festo
preprint2SAE-PP-009964/27/2022
preprint2
Mutagaana, Festo
Gland Design, O-Ring and Other SealsAS4716D (Current)11/9/2021
This SAE Aerospace Standard (AS) provides standardized gland (groove) design criteria and dimensions for O-ring seal glands for static and dynamic applications, and other seals.
A-6C2 Seals Committee
automobile's nviehfSAE-PP-0047610/6/2021
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 materia
Mutagaana, Festo
SM0003-TestSAE-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-TestSAE-PP-004549/25/2021
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
Suitable Test Sizes for O-ring SpecificationsARP3050A (Current)9/8/2021
There are many tests that have been developed to characterize rubber O-rings. Many of these tests are independent of the size of the O-ring being tested. However, there are some tests, specifically, stress/strain properties, that are a function of the O-ring’s size. The purpose of this report is to provide guidelines for specifying O-rings that would be considered “suitable for testing” when writing O-ring material specifications.
AMS CE Elastomers Committee
Testing-legacypublishingSAE-PP-003766/22/2021
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SintzUSER, Jeneane
CONNECTOR, RECEPTACLE, ELECTRIC THRU BULKHEAD, WALL MOUNTING FLANGE, SERIES I (CLASS E)AS31391 (Current)6/22/2021
AE-8C1 Connectors Committee
Aircraft Tail BumpersAIR1800B (Current)6/22/2021
This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.
A-5B Gears, Struts and Couplings Committee NEW Name Goes Her
Motorcycle Bank Angle Measurement ProcedureJ1168_202104 (Current)4/6/2021
The purpose of this SAE Standard is to specify the procedure for measuring the bank angle of motorcycles.
Motorcycle Technical Steering Committee
6.0.120 - Investigation of the Applicability of Numerical Noise Prediction of an Axial Vehicle Cooling FanSAE-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
Aircraft Tail BumpersAIR1800A (Historical)2/3/2021
This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.
A-5B Gears, Struts and Couplings Committee NEW Name Goes Her
The Effect of Change in Assembly Sequence on Permanent Strain of Cab Suspension Console02-13-02-00118/20/2020
Heavy commercial vehicles play an important role in creating the trade and economic balance of countries. Also, the durability and safety of heavy commercial vehicles come to the fore. Heavy commercial vehicles consist of two parts. These are the chassis area with the equipment that allows the vehicle to move and the cabin section where the driver is located. The cabin area is the most important area that ensures the highest level of driver safety. Considering that the production of trucks is increasing day by day, it is inevitable for companies to increase their R&D activities in the field of cabin and cabin suspension systems for much safer, durable, and comfortable trucks. This study aims to determine the safe torque value of the fasteners and their assembly sequence of the Cab Suspension Console, which is one of the most important connection parts in a truck and which can cause a fatal accident by breaking. In this study, the safe torque value of the fasteners of the cabin suspension console has been determined as 180 ± 15 Nm/180 ± 10 Grad for the outer fasteners and 225 ± 18 Nm/180 ± 10 Grad for the inner fasteners. In addition, two different assembly sequences are determined and permanent strains on the part are measured. At the end of the assembly test, permanent strains on the part and other factors affecting the strain are simulated. According to the results obtained, the assembly sequence with a low permanent strain value is chosen and commissioned in production.
Yildirim, Bariscan, Öztürk, Dogan
Hybrid Fuzzy-PID Control Development for a Truck Air Suspension System02-13-01-00045/11/2020
A hybrid fuzzy and proportional-integral-derivative (PID) controller is proposed for roll angle handling of a three-axle truck with an active air suspension system. The conventional truck suspension system has four air springs for the rear wheels and two leaf springs for the front wheels, which cannot properly control the pitch angle, and here in this study is upgraded into front air springs. Therefore in the full air suspension system, the pitch angle is controlled by the active suspension system. Roll reduction of a heavy vehicle can improve the ride comfort and rollover tendency of the truck, simultaneously. The relation of air spring pressures and vehicle dynamics is developed in a simple and accurate model. Using this comprehensive model, it is possible to control the variables of vehicle dynamics such as roll, pitch, and height of the truck. The truck air suspension system is examined in step steering, fishhook, and asymmetric rough road (types E and G power spectral density [PSD] road) tests. The fuzzy input is a normalized roll angle and the output is the normalized mass flow rate (of the air springs). Both of the fuzzy input and output have nine membership functions (MFs), which have optimized with the genetic algorithm (GA) method. The optimization cost function is a combination of maximum and integral of the absolute roll angle of the truck sprung mass. Besides, the PID controller is tuned by the Ziegler-Nichols method at the first stage and optimized by the GA method. The results show that the optimized fuzzy controller has good roll performance in a different test; however, the simple PID addition to the fuzzy controller can improve vehicle comfort and stability.
Nazemian, Hossein, Masih-Tehrani, Masoud
N&V Component Structural Integration and Mounted Component Durability Implications2020-01-13964/14/2020
Exterior component integration presents competing performance challenges for balanced exterior styling, safety, ‘structural feel’ [1] and durability. Industry standard practices utilize noise and vibration mode maps and source-path-receiver [2] considerations for component mode frequency placement. This modal frequency placement has an influence on ‘structural feel’ and durability performance. Challenges have increased with additional styling content, geometric overhang from attachment points, component size and mass, and sensor modules. Base excitation at component attachment interfaces are increase due to relative positioning of the suspension and propulsion vehicle source inputs. These components might include headlamps, side mirrors, end gates, bumpers and fascia assemblies. Here, we establish basic expectations for the behavior of these systems, and ultimately consolidate existing rationales that are applied to these systems. We consider a simple two degree-of-freedom system subject to a base excitation consisting of masses attached via springs and dampers. Component mode decoupling, vibration amplification and basic design guidance relationships are suggested.
Stebbins, Mark, Schudt, Joseph
Vibration Control of Semi-Active Vehicle Suspension System Incorporating MR Damper Using Fuzzy Self-Tuning PID Approach2020-01-10824/14/2020
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.
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
Design and Fabrication of Carbon Fibre/Epoxy-Aluminum Hybrid Suspension Control Arms for Formula SAE Race Cars2020-01-02304/14/2020
Suspension system of a vehicle plays an important role to carefully control motion of the wheel throughout the travel. The vertical and the lateral dynamics (ride and handling) is affected by the unsprung-to-sprung mass ratio. Lower value of this mass ratio leads to enhanced performance of the car. To optimize the unsprung mass of the car, design of control arm plate is optimized with Aluminum material and Carbon fibre reinforced composite control arms framework are used to achieve high stiffness to weight ratio. These leads to increase in overall power to weight ratio of the car which helps to deliver maximum performance to the wheels. Through analysis of real-life working conditions of the entire steering knuckle assembly in ACP pre- post ANSYS 18.1 with the defined boundary conditions, equivalent stress and total deformations are obtained. Based on the results, geometrical topology of the control arms plates is further optimized. After several tensile tests on different bond length and bond gap, the outer surface of control arm tube was bonded to the inner surface of control arm plate with a bond length of 30mm using the DP 490 adhesive. The carbon fibre/epoxy aluminum framework design achieved a weight reduction of 4 kgs from the AISI 1020 control arm assembly.
Gupta, Mayank, Porwal, Akash, Budi, Harshvardhan Rao, Krishnan, Padmanabhan, Hande, Pramod
Parameter Optimization of Anti-Roll Bar Based on Stiffness2020-01-09214/14/2020
The anti-roll bar is an important structural component of the automobile, which can effectively prevent the automobile from rolling and improve the safety of the automobile during steering. In the design of the current anti-roll bar, the stiffness is determined by empirical or oversimplified mathematical models, often not reaching the optimal value. In this paper, eight parameters are used to determine the structure of the anti-roll bar. Combining the Deformation Energy theorem and Castigliano’s theorem, a mathematical model of the stiffness is established. The optimal solution and corresponding parameter values of the mathematical model are obtained by nonlinear programming and genetic algorithm. The influence of structural parameters on the anti-roll bar stiffness is analyzed, and the regular pattern of design is obtained. In addition, the finite element method is used to verify the stiffness solution model. In the experiment, the anti-roll bar designed by the regular pattern is attached to the Baja Racing, and the stiffness of the bar is changed by adjusting the length of the arm of the bar, then the correctness of the design regular pattern is verified by testing the roll response. The improved anti-roll bar can effectively improve the anti-roll stiffness and has a better effect on the cornering stability of the automobile.
Wang, Zhenyu, Guo, Donghua, Wang, Haoyu, Tan, Gangfeng, Jiang, Yifeng, Li, Ming, Hou, Xiaoge
A Study on Sliding Mode Control for Active Suspension System2020-01-10844/14/2020
Sliding mode control with a disturbance observer (SMC-DO) is proposed for suppressing the sprung mass vibration in a quarter-car with double-wishbone active suspension system (ASS), which contains the geometry structure of the upper and lower control arms. The governing equations of double-wishbone ASS are obtained by the balance-force analysis of the sprung mass in ASS. Considering uncertainties in damping, stiffness, and external disturbance acting on the sprung mass, we design a disturbance observer based on a sliding mode control (SMC) to estimate these uncertainties under the unknown road excitation. By the Lyapunov minimax approach, the uniform boundedness and the uniform ultimate boundedness of ASS with the proposed control are rigorously proved. Through co-simulation of ADAMS software and MATLAB/Simulink software, the sprung mass acceleration of ASS can be obtained with and without the proposed control. The results show that ASS with the proposed control can yield better riding comfort performance of vibration attenuation of the sprung mass, which verifies the effectiveness of the proposed approach. Furthermore, the effects of external disturbance and control parameter in the disturbance observer on the sprung mass acceleration are investigated.
Qin, Wu, Shangguan, Wen-Bin, Xu, Pu, Feng, Huayuan, Sun, Yi
A McPherson Lightweight Suspension Arm2020-01-07724/14/2020
The paper deals with the design and manufacturing of a McPherson suspension arm made from short glass fiber reinforced polyamide (PA66). The design of the arm and the design of the molds have been made jointly. According to Industry 4.0 paradigms, a full digitalization of both the product and process has been performed. Since the mechanical behavior of the suspension arm strongly depends on constraints which are difficult to be modelled, a simpler structure with well-defined mechanical constraints has been developed. By means of such simple structure, the model for the behavior of the material has been validated. Since the suspension arm is a hybrid structure, the associated simple structure is hybrid as well, featuring a metal sheet with over-molded polymer. The issues referring to material flow, material to material contact, weld lines, fatigue strength, high and low temperature behavior, creep, dynamic strength have been investigated on the simple structure. The detailed understanding gained with the simple structure has been transferred on the actual suspension arm. The McPherson arm has been produced and withstood the technical specifications.
Belingardi, Giovanni, Bernasconi, Andrea, Chessari, Marcello, Maccarinelli, Silvia, Mastinu, Giampiero, Previati, Giorgio, Scattina, Alessandro, Spini, Erico
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
Behavioral Study on Passenger and Driver Dynamics Utilizing 14-DOF Half Car Active Suspension System2020-01-10064/14/2020
The main aim of the current research work is to investigate the behavior of passenger and driver biomechanics when the vehicle is excited under road irregularities. For this purpose, a 14-degrees of freedom (DOF) human-vehicle-road model was proposed. In addition to that, the ride comfort of the occupant with the aid of active suspension and its influence on other performance indices like suspension working space and road holding were also investigated. Besides sprung mass acceleration, the ride comfort was evaluated with pitching acceleration and occupant’s head acceleration representation. Active suspension based on Proportional Integral Derivative (PID) controller with hydraulic actuator was implemented. Then, the parameters of the PID controller are optimally tuned by adopting genetic algorithm (GA) with the assist of integral time absolute error (ITAE) method. The objective function was obtained by combining the ITAE of tire deflection, suspension deflection and sprung mass motion. Various road profiles such as single bump and random profile were generated and tested on the proposed controller vehicle model to guarantee the robustness. Numerical examples were presented under frequency and time domains to clearly demonstrate the effectiveness of the proposed GAPID-based active suspension system over the passive system. Furthermore, the Seat-To-Head transmissibility ratio (STH) for driver and passenger was established to comprehend the behavior.
Anandan, Arivazhagan, K, Arunachalam
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
2021 Cadillac Escalade brings a dash of curved OLED - and a diesel20AUTP03_133/1/2020
Cadillac has unveiled the 2021 Escalade and will differentiate the full-size SUV from its Tahoe/Yukon platform-mates with a large dose of exclusive technologies including Super Cruise, audio systems from new partner AKG and the industry's slickest display-screen integration. Gaining similar mechanical benefits as its platform siblings, including wheelbase stretches and the new independent rear suspension (IRS) that should improve dynamics along with seating/cargo space, the all-new 2021 Escalade leverages the platform's new digital network architecture (see p.10) to raise the bar for integrated infotainment technology. The 2021 Cadillac Escalade makes use of GM's new GMT T1XX platform that began underpinning its pickup trucks in 2019, and serves as the basis of the upcoming MY2021 Chevy Tahoe/Suburban and GMC Yukon/Yukon XL full-size SUVs. In the fifth generation of Cadillac's longest-running nameplate, this equates to the same notable passenger space and interior volume gains for the 2021 Escalade, which was only revealed in the standard-length model. The longer Escalade ESV is expected to be unveiled at the 2020 New York Auto Show.
Seredynski, Paul
Spring Drive FittingTBMG-361833/1/2020
Valve and tube manufacturers continue to battle the problem of fitting pipes and tubing together quickly and reliably. The spring drive fitting addresses this challenge, bridging the gap between solutions for small-diameter tube fittings commonly seen in high-pressure, low-flow-area pneumatic systems and solutions for large flanges used in low-pressure, high-flow-area hydraulic systems.
Control Performance of Damping and Air Spring of Heavy Truck Air Suspension System with Optimal Fuzzy Control10-04-02-00132/28/2020
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 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
Better Solutions for Testing and Measuring Compression and Extension SpringsTBMG-359562/1/2020
The design, manufacture, and use of springs can be traced back in time to The Bronze Age. Spring design is a science based on complex arithmetic calculations combined with material science. Springs are used in everyday consumer devices including cellular phones and computers, in industrial applications including automotive and aerospace, and in precision medical devices where a spring with a diameter of .0036” (about equal to the size of a human hair) is used in catheters and endoscopic instruments.
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
A Study of the Control Logic of Electronically Controlled Suspension for Motorcycle2019-32-05691/24/2020
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
Numerical optimization of independent suspension hardpoint2019-36-01541/13/2020
The present work aims to use complex tools for the calculation of vehicle dynamics, using optimization analysis. The study was applied to a single seat off-road prototype that has independent suspension, Double A or WishBones type, both on the front and rear axles and whose main objective will be the analysis of the prototype suspension arms fixing points. A multi-body model was created by MotionView software and straight-line acceleration and deceleration analyzes were applied to obtain better longitudinal load transfer ratios for the axes, besides the force measurements for the arm connections during these events. After the creation of the multi-body model, some studies using optimization tools, through HyperStudy software, were performed in order to obtain the new positions of the attachment points in the chassis, achieving a better dynamic suspension design. The new points change the longitudinal load transfer design and generate controlled alteration between predefined parameters in the behavior of the camber and toe in angles resulting in a different suspension arm geometry. In addition, the new geometry also had a pickup analysis of forces for comparison between models. At the end of the study, the prototype model generated allows full comparison of the macro operation of the prototype, and allowing the developers to evaluate if this model is more efficient and robust than the previous one. The optimization tool allows to find important results that allow the studied competition prototype to gain competitive advantages contributing to achieve better results and a better design.
Alvim, Olavo Fava Furtado, Silveira, Marcio Eduardo
WHAT WE'RE DRIVING20AUTP02_081/1/2020
A summer job during college gave me occasion to drive a Mack R-model dump truck. This Class-8 bruiser's inline-six diesel delivered 280 hp and 1,000 lb-ft (1,356 Nm). I thought of that smoky old Mack while driving Ford's latest SuperDuty pickups in real-world hauling demos in the Arizona mountains. Ford's upgraded 6.7-L turbodiesel V8 delivers amazing Mack-mauling grunt-1,050 lb-ft and 475 hp-for nearly any task. With a 37,000-lb max towing rating, the big pickup didn't break a sweat hauling a 12,000-lb, 33-ft-long RV trailer over the mountains. Indeed, the Ford engineers on hand also could have loaded the F-350's cargo bed to its 7,850-lb max payload and their baby would've obliged without fuss. And no need for old-school gear-jamming: Ford's new in-house-engineered 10-speed HD automatic provided a ratio for every situation.
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
Heavy Dump TruckTBMG-3567512/1/2019
Mack Defense Allentown, PA 1 (800) 866-1177
The Three Rs of Analog Position Sensor-Based Mechanical MeasurementsTBMG-3568112/1/2019
Those of us old enough to remember the “good old days” recall that grade school focused on learning the 3 R's: reading, ‘riting, and ‘rithametic. In the world of sensors, there are also 3 R's: Repeatability, Resolution, and Response. As important as these sensor parameters are, there is often confusion in the mind of users about exactly what they mean and in what ways they tend to interact with each other. This article will attempt to explain the 3 R's for position sensors and dispel any confusion that might exist.
Countering the Destabilizing Effects of Shifted Loads through Pneumatic Suspension Design10-04-01-000111/8/2019
This article proposes a novel approach to reduce the destabilizing impacts of the shifted loads of heavy trucks (due to improper loading or liquid slosh) by pneumatic suspension design. In this regard, the pneumatically balanced suspension with dual leveling valves is introduced, and its potential for the improvement of the body imbalance due to the shifted load is determined. The analysis is based on a multi-domain model that couples the suspension fluid dynamics, shifted-load impacts, and tractor-semitrailer dynamics. Truck dynamics is simulated using TruckSim, which is integrated with the pneumatic suspension model developed in AMESim. This yields a reasonable prediction of the effect of the suspension airflow dynamics on vehicle dynamics. Moreover, the ability of the pneumatic suspension to counteract the effects of two general shifted loads - static (rigid cargo) and dynamic (liquid) - is studied. The simulation results indicate that the dual-leveling-valve suspension results in a reduction in roll angle and roll rate of the vehicle body for both static and dynamic load-shifting cases, as compared to the conventional single-leveling-valve suspension. Suppression of the liquid sloshing behavior is obtained by the truck with the dual-leveling-valve suspension. Furthermore, the co-simulation platform established in the study is useful for efficient and accurate analyses of the coupled shifted load-pneumatic suspension-vehicle system dynamics.
Chen, Yang, Ahmadian, Mehdi
Research on Control Algorithm of Active Steering Control Based on the Driver Intention2019-01-506411/4/2019
Active steering technology can improve the operability of the driver by the involvement to the steering system. Driver is the major controller of the vehicle Therefore, the involvement of advanced technologies including the active steering technology shouldn’t interfere with the intention of the driver, and the driver should still have great control of the vehicle. The aim of this paper is to solve the problem of the driver’s control when the active steering system works to improve the flexibility of the low speed and the stability of the high speed, and the active steering model based on the driver’s steering intention is established. Through the CarSim simulation software, this paper adopts 9 parameters related to the vehicle steering of the DLC (Double Line Change). And PCA (Principal Component Analysis) algorithm, a tool of statistical analysis, is applied to select 4 parameters which can stand for the DLC from the 9 parameters, which makes the data processing easier. Through the 4 parameters, this model divide the driver’s steering intention into four categories (emergency steering, normal steering, turn left and turn right) having different weights of active steering angle by clustering analysis, which ensures the driver get better control to the vehicle than traditional active steering system at different steering conditions. Finally, the feasibility of this model is verified by the simulation results through the comparison with the curve of the ideal steering at DLC steering condition.
Zhang, Pengcheng, Zheng, Hongyu
Spring Calculations Using Noonan’s XymT Method and an Eccentric Force03-13-01-000710/14/2019
Abstract The usual method of calculating spring deflection is to assume the end force acts through the central axis of the spring. The author takes a different approach where he calculates the eccentricity of the end force and from this calculates the spring deflection due to combined bending and torsion using a completely new model which he names the Noonan XymT Method. Also, the usual method widely used, where a strain energy approach is used, is proven to be in error. That statement is proven using a special example. Rough measurements have shown that the displacements calculated using the Strain Energy Method, can have errors as high as 40%, at a position up 0.6 coils from the bottom of the spring, and 10% at the top of the spring. The reason for this error has been identified, and calculations using Noonan’s XymT Method greatly reduces, if not eliminates, this error. This is particularly relevant in calculating individual coil stiffness and binding. With the displacement calculated, the combined complex stress due to bending tensile stress and torsional shear stress is calculated. An unusual observation was found, where 3° bending of the valve stem results in a 48% higher spring stress.
Noonan, Michael
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
Considerations for Suspension ModificationJ2492_201910 (Current)10/9/2019
The scope of this document is limited specifically to the following types of passenger vehicles: automobiles, light trucks, and sport/utility vehicles. This document addresses modifications as they apply to legal use of the vehicle, and examines suspension modification as it applies to stock (as manufactured) ride height, and changed (raised or lowered) ride height. Note that modifications of ride height are considered, exclusive of wheel and/or tire modifications, which can also have potentially serious side effects, and are outside the scope of this document.
Motor Vehicle Council
Waveform Synthesis for Shock Response Spectrum Replication, Applied to Ground Vehicle Component TestingTBMG-3535410/1/2019
The motivation for this work is to mitigate shock levels on vehicle components, through testing new designs of equipment. The objective is to generate a time history to perform shock testing on military and commercial ground vehicle components. The time histories are used to drive hydraulic actuators coupled to a test specimen.
Brake Squeal Prevention through Suspension Design and Adaptive Suspension10-03-03-00119/3/2019
The brake squeal phenomenon has bothered automobile manufacturers for a long time. Although having no ill effects on the braking performance, the squeaky noise is often a nuisance and one of the major complaints of many customers. In order to design quality and noise-free automobiles, the brake squeal issue has to be permanently tackled. Many researchers have suggested shape optimization and additional damping of the disk as brake squeal control measures. Other methods proposed in the literature include the use of a different brake pad material or an anti-squeal paste. However, the effect of the type of brake pad suspension on brake squeal has not been studied. In this article, we demonstrate that the use of a 4-element viscoelastic support can prevent brake squeal for a vehicle speed of 5-200 kmph, which is the practical vehicle speed range. For a 2-element support, we have identified a suitable control parameter and proposed an efficient active control for squeal prevention based on that. A nondimensional analysis has been carried out so as to ensure that the results are applicable for any system.
Saxena, Shashank, Dutt, Jayanta Kumar
2020 Hyundai Palisade: New chassis, Atkinson V619AUTP09_139/1/2019
The three-row 2020 Hyundai Palisade's strong, stable and quiet body structure serves as the starting point for ride quality, roll control and a quiet cabin. “We put a lot of resources toward this vehicle knowing it was going to be Hyundai's flagship SUV,” Michael O'Brien, vice president of product, corporate and digital planning for Hyundai Motor America, said at a recent media ride-and-drive program. With more headroom and legroom, larger exterior dimensions and more cargo volume than the three-row, 7-passenger Santa Fe XL it replaces, the 8-passenger Palisade is a newcomer to the segment that includes the all-new, 6th-generation Ford Explorer, Honda Pilot, Mazda CX-9, Toyota Highlander, Nissan Pathfinder and Volkswagen Atlas.
Buchholz, Kami
Miniature Spring Performance TesterTBMG-351409/1/2019
In order to qualify miniature springs, manufacturers of these systems rely on commercially available testers that are designed for large-scale springs (>0.5" diameter). Commercially available spring test systems lack sufficient force resolution or cyclic test capabilities for miniature-scale springs. Traditional spring testers work on the basis of compressing (or extending) a spring to a known deflection and recording that force value, then moving to the second known deflection and recording that force value. This is done manually by a user and has no capability of automation or fatigue.
WHAT WE'RE DRIVING19AUTP09_089/1/2019
As the sporting player in Volvo's C-segment sedan lineup, this all-wheel drive, turbocharged-and-supercharged R-Design S60 faces benchmark competition in the BMW 3-Series, Audi A4 and Mercedes-Benz C-Class. In pure performance, the stylish Swede stacks up nicely against the Germans: Its 316 hp (236 kW) pushes the 3,900 lb (1769 kg) car plus my 200-lb (91 kg) of dead weight from a standstill to 60 mph (97 km/h) in 5.5 s, according to my stopwatch. Dynamically, the S60 T6 (not my choice of nomenclature, as it's a 4-cyl., not a six) feels solid and secure, if not exceptionally nimble, when pushed hard in the corners. But where the S60 R-Design clearly beats the others is inside, the area where Volvo shows its taillamps to the other premium brands. The S60's cabin is a beautifully integrated blend of rich materials and tasteful accents - brushed aluminum of the lower IP contrasting with deep ebony, offset by delightful-to-touch control knobs. The front seats are both handsome and comfortable. Rear-seat legroom is excellent, as my 37-in. (940-mm) inseam can attest.
Minimizing Power Consumption of Fully Active Vehicle Suspension System Using Combined Multi-Objective Particle Swarm Optimization2019-01-50777/16/2019
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.
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