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Enhancement of Occupant Ride Comfort by GA Optimized PID Control Active Suspension System

Anna University-Arivazhagan Anandan, Arunachalam K
  • Technical Paper
  • 2020-01-1532
To be published on 2020-06-03 by SAE International in United States
The main objective of this work is to enhance the occupant ride comfort. Ride comfort is quantified in terms of measuring distinct accelerations like sprung mass, seat and occupant head. For this theoretical evaluation, a 7- degrees of freedom (DOF) human-vehicle-road model was established and the system investigation was limited to vertical motion. Besides, this work also focused to guarantee other vehicle performance indices like suspension working space and tire deflection. A proportional-integral-derivative (PID) controller was introduced in the vehicle model and optimized with the aid of the genetic algorithm (GA). Actuator dynamics is incorporated into the system. The objective function for PID optimization was carried out using root mean square error (RMSE) concept. The severity of various suspension indices and biomechanics responses of the developed model under proposed approach were theoretically analyzed using various road profiles and compared with conventional passive system. Furthermore, this work discussed the seat to head transmissibility ratio (STH) response to examine the severity of whole-body vibration (WBV). Subsequently, the respective performance measures were statistically analyzed using root mean square…
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Sliding Mode Controlled Half Car Suspension System with Magnetorheological Damper

Anna University-AROCKIA SUTHAN SOOSAIRAJ, ARUNACHALAM K
  • Technical Paper
  • 2020-01-1540
To be published on 2020-06-03 by SAE International in United States
Attenuation of vibrations caused by the road undulance conditions are tedious and very much related to human health and vehicle handling problems. One of the promised approaches to solving these problems in a vehicle suspension system is the use of effective controllers. In this paper, the sliding mode controller (SMC) is designed and used to control the magnetorheological (MR) damper. The performance of the proposed controller is verified by incorporating the controller in a half car vehicle suspension model. In a suspension damper design, Modified Bouc-Wen model is used to characterize the hysteretic behaviour of MR damper parameters. The voltage control algorithm is used to convert the desired force into the varied voltage input to the MR damper. The fail-proof advantage of MR damper is analysed by comparing the results of uncontrolled MR suspension with a passive system. In order to limit the pitch angle and to achieve the improved ride comfort and stability of the vehicle, the vertical displacement of the front and rear body of the half-car model is controlled by the SMC…
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Real-Time Capable Wind and Rolling Noise Synthesis for a More Realistic Vehicle Simulator Experience

Institute of Electronic Music & Acoustic-Julian Koch, Alois Sontacchi
MAGNA STEYR Fahrzeugtechnik AG & CO KG-Thorsten Bartosch, Werner Reinalter
  • Technical Paper
  • 2020-01-1546
To be published on 2020-06-03 by SAE International in United States
Nowadays a large proportion of the overall acoustic vehicle development takes place within virtual phases. Increasingly, projects require the auralization of virtual developed acoustics measures, e.g. from the disciplines of electro-acoustic, ride comfort, rolling noise or passive acoustic on dynamic or static driving simulators. In practice it turns out that in addition to engine noise also a realistic reproduction of rolling and wind noise is important. In this article, approaches to synthetic rolling and wind noise generators are discussed. We developed such real-time capable sound generators that are parametrizable according to arbitrary driving conditions. Furthermore, spacial reproduction of the driving sounds is achieved for binaural headphone, as well as for other arbitrary loudspeaker setups, like often found in driving simulators. Derived models and parametrization are based on measurements and recordings from several real vehicles. In order to facilitate the adjustment on specific vehicles and designing rolls thereof, the suggested parametrization is guided by a defined procedure. The influence of these noise components on an improved perception of the overall driving experience is objectified by means…
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Asian Consumers Challenging the NVH Performance of European Cars – Implications on the Product Development in the 2020ies

MAGNA STEYR Automotive Technologies-Paulo Padilha
NVH Experts-Christoph Fankhauser
  • Technical Paper
  • 2020-01-1552
To be published on 2020-06-03 by SAE International in United States
Sales of SUV and luxury cars on the largest market of the world – China – are growing at a high rate. The highways in large cities like Beijing or Shanghai are increasingly populated with cars from all over the world like Japan, USA, Europe and Korea and even some refined domestic brands. More than 10 million rich people can afford those cars and are skilled drivers. This huge group of potential consumers is targeted by luxury brand OEMs and by startup companies. It has been understood, that these people have a strong attitude towards comfort. The twistbeam rear axle was replaced by multilink, double clutch transmissions were improved by comfort-mode drive programs, interior trims raised to Western standard performance levels, tyres specially developed for comfort in China, localized insulation materials and packages engineered to a one vehicle class higher level. The European avant-garde is capable of such high levels of complete vehicle NVH performance, whereas premium brands often compromise NVH with respect to high vehicle dynamics performance and passive safety requirements. At the same…
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Simulating and Optimizing the Dynamic Chassis Forces of the Audi e-tron

Audi AG-Stefan Uhlar
  • Technical Paper
  • 2020-01-1521
To be published on 2020-06-03 by SAE International in United States
With battery electric vehicles (BEV), due to the absence of the combustion process, the rolling noise comes even more into play. The BEV technology also leads to different concepts of how to mount the electric engine in the car. Commonly, also applied with the Audi e-tron, the rear engine is mounted on a subframe, which again is connected to the body structure. This concept leads to a better insulation in the high frequency range, yet it bears some problems in designing the mounts for ride comfort (up to 20Hz) or body boom (up to 70Hz). Commonly engine mounts are laid-out based on driving comfort (up to 20Hz). The current paper presents a new method to find an optimal mount design (concerning the stiffness) in order to reduce the dynamic chassis forces which are transferred to the body up to 100Hz. This directly comes along with a reduction of the sound pressure level for the ‘body boom’ phenomena. Here we use multibody simulation along with a sophisticated tire model in the time domain in order to…
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Research on the Subjective Rating Prediction Method for the Ride Comfort with Deep Learning

Hitachi Automotive Systems, Ltd-Ryusuke Hirao
Hitachi Automotive Systems, Ltd.-Nobuyuki Ichimaru
  • Technical Paper
  • 2020-01-1566
To be published on 2020-06-03 by SAE International in United States
Suspension is an important chassis part which is vital to ride comfort. However, it is difficult to achieve our targeted comfortability level in a short time. Therefore, improving efficiency of damper development is our primary challenge. We have launched a project which aims to reduce the workload on developing dampers by introducing analytical approaches to the improvement of ride comfort. To be more specific, we have been putting effort into developing subjective rating prediction, vehicle dynamics prediction, the damping force prediction. This paper describes the subjective rating prediction method which output a subjective rating corresponding to the physical value of the vehicle dynamics with Deep Learning. As a result of verifying with the unlearning data, DNN(Deep Neural Network) prediction method could almost predict the subjective rating of the expert driver.
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Nonlinear Model Predictive Control of Autonomous Vehicles Considering Dynamic Stability Constraints

Tongji University-Xunjie Chen, Guangqiang Wu, Meng Ren
  • Technical Paper
  • 2020-01-1400
To be published on 2020-04-14 by SAE International in United States
Autonomous vehicle performance is increasingly highlighted in many highway driving scenarios, which leads to more priorities to vehicle stability as well as tracking accuracy. In this paper, a nonlinear model predictive controller for autonomous vehicle trajectory tracking is designed and verified through a real-time simulation bench of a virtual test track. The dynamic stability constraints of nonlinear model predictive control (NLMPC) are obtained by a novel quadrilateral stability region criterion instead of the conventional phase plane method using the double-line region. First, a typical lane change scene of overtaking is selected and a new composited trajectory model is proposed as a reference path that combines smoothness of sine wave and comfort of linear functional path. Reference lateral velocity, azimuth angle, yaw rate, and front wheel steering angle are subsequently taken into account. Then, by establishing a nonlinear vehicle dynamics model where Magic Formula of nonlinear tire model is adapted, the quadrilateral vehicle stability region is defined in consideration of designed velocity, road adhesion coefficient, and front wheel steering angle. Working condition-variant constraints determined by the…
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Second-Order Sliding Mode Controller for Performance Analysis of Quarter Car Magnetorheological Suspension System

Anna University-Arockia Suthan Soosairaj, Arunachalam K
  • Technical Paper
  • 2020-01-1005
To be published on 2020-04-14 by SAE International in United States
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…
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Customer Perception of Road-Induced Structural Feel

General Motors LLC-Mark Stebbins, John Cafeo, Mark Beltramo
  • Technical Paper
  • 2020-01-1080
To be published on 2020-04-14 by SAE International in United States
Structural feel, or “vehicle feels solidly built” is a subjective measure that traditionally has been assessed by technical experts and executives. Vehicle programs’ timing and viability can be affected by these assessments. Objective measures would improve the vehicle development process. The first step in developing objective measures is to assess whether road-induced structural feel can be sensed by the customer. To this end, an internal drive clinic was conducted and proved to be an effective approach for obtaining customer perception of structural feel. Vehicles that spanned a range of excellent to poor structural feel were chosen by experts as part of the experimental design. The non-expert participants rank-ordered the vehicles’ structural feel performance in the order determined a priori by the experts. Results also indicate that the question “vehicle feels solidly built” is a good overall question for assessing structural feel.
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Micro-Mobility Vehicle Dynamics and Rider Kinematics during Electric Scooter Riding

Exponent Inc.-Christina MR Garman, Steven G. Como, Ian C. Campbell, Jeffrey Wishart, Kevin O'Brien, Scott McLean
  • Technical Paper
  • 2020-01-0935
To be published on 2020-04-14 by SAE International in United States
Micro-mobility is a fast-growing trend in the transportation industry with stand-up electric scooters (e-scooters) becoming increasingly popular in the United States. To date, there are over 350 ride-share e-scooter programs in the United States. As this popularity increases, so does the need to understand the performance capabilities of these vehicles and the associated operator kinematics. Scooter tip-over stability is characterized by the scooter geometry and controls and is maintained through operator inputs such as body position, interaction with the handlebars, and foot placement. In this study, testing was conducted using operators of varying sizes to document the capabilities and limitations of these e-scooters being introduced into the traffic ecosystem. A test course was designed to simulate an urban environment including sidewalk and on-road sections requiring common maneuvers (e.g., turning, stopping points, etc.) for repeatable, controlled data collection. A commercially available e-scooter was instrumented to measure acceleration and velocity, steering angle, roll angle, and GPS position. Operators ranging from the 15th percentile to the 85th percentile were instrumented with wearable sensors to gain insight into the…