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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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Thermal Management and Performance Characteristic of Electric Vehicle

Tata Motors Ltd-Sanjoy Biswas, Asmita Ghate
  • Technical Paper
  • 2020-28-0022
To be published on 2020-04-30 by SAE International in United States
Thermal Management System is one of key parallel branch for internal combustion engine (ICE) vehicle over 4 decades as it ensures performance of power train/engine or after treatment system or HVAC (Climate control). In automotive industry, Range Anxiety and safety of Electric Vehicle (EV) are the hot topic of discussion. This paper is dealing with some importance aspects of thermal management system and their link with the performance/Safety Parameter of Electric vehicle. Battery Cooling or Battery thermal management System (BTMS or BCS) and Traction cooling system (TCS) are coupled with near conventional HVAC circuit. BTMS plays important role to ensure performance of Li-ion Battery pack which is indirectly related with Range and safety of electric vehicle. Similar, other 2 Cooling circuit has major role to ensure vehicle performance and comfort. Here, Thermal management system become utmost important to overcome the challenge of range and safety concern of EV along with many other factors. Also, Thermal management system sited in key research arena along with battery technology for Electric and Hybrid Electric Vehicle.
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Formula SAE Data Acquisition and Detailed Analysis of a Lap

Georgia Southern University-Connor M. Ashford, Aniruddha Mitra
  • Technical Paper
  • 2020-01-0544
To be published on 2020-04-14 by SAE International in United States
Formula Society of Automotive Engineers (FSAE) International is a student design competition organized by SAE. The student design involves engineering and manufacturing a formula style racecar and evaluating its performance. Testing and validation of the vehicle is an integral part of the design and performance during the competition. At the collegiate level the drivers are at the amateur level. As a result, the human factor plays a significant role in the outcome of the dynamic events. In order to reduce the uncertainty factor and improve the general performance, driver training is necessary. Instead of overall performance of the driver based on individual lap, our current research focuses on the more detailed components of the driver’s actions throughout different sections of the lap. A complete lap consists of several components, such as, straight line acceleration and braking, max and min radius cornering, slalom or “S” movements, and bus stops or quick braking and turning. In order to evaluate the performance of each driver in each of these components, an AiM data acquisition system is mounted in…
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Development and Application of a Collision Avoidance Capability Metric

AAA Northern California Nevada & Utah-Paul Wells, Atul Acharya
Dynamic Research Inc.-Jordan Silberling, Joseph Kelly, John Lenkeit
  • Technical Paper
  • 2020-01-1207
To be published on 2020-04-14 by SAE International in United States
This paper describes the development and application of a newly developed metric for evaluating and quantifying the capability of a vehicle/controller (e.g., Automated Vehicle or human driver) to avoid collisions in nearly any potential scenario, including those involving multiple potential collision partners and roadside objects. At its core, this Collision Avoidance Capability (CAC) metric assesses the vehicle’s ability to avoid potential collisions at any point in time. It can also be evaluated at discrete points, or over time intervals. In addition, the CAC methodology potentially provides a real-time indication of courses of action that could be taken to avoid collisions. The CAC calculation evaluates all possible courses of action within a vehicle’s performance limitations, including combinations of braking, accelerating and steering. Graphically, it uses the concept of a “friction ellipse”, which is commonly used in tire modeling and vehicle dynamics as a way of considering the interaction of braking and turning forces generated at the tire contact patches. When this concept is applied to the whole vehicle, and the actual or estimated maximum lateral and…
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Improved Customer Experience through Electric Vehicle Sound Enhancement

General Motors LLC-Frank Valeri, Glenn Pietila
  • Technical Paper
  • 2020-01-1361
To be published on 2020-04-14 by SAE International in United States
Electric Vehicles are typically thought of as being quiet and refined, but they do come with some unique N&V challenges. Some of these challenges include a natural sound that can be undesirable due to its tonal nature, presence of high frequency, discontinuities in sound, and characteristics and levels that do not always naturally increase with motor torque and vehicle speed. One approach to address those challenges is Electric Vehicle Sound Enhancement (EVSE) which is a software feature embedded within the infotainment system. EVSE can be used to improve the perception of the vehicle by enhancing the preferred natural sounds of the vehicle, masking unusual and annoying components of the sound and aurally conveying information related to the vehicle performance. A jury study was conducted to better understand how EVSE can be used to accomplish this. This paper will summarize a typical EVSE system and highlight some of the tools and methods that can be used to develop an EVSE tuning that mitigates unpleasant sounds while enhancing the customer experience without completely changing the vehicle DNA.…
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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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Automated Highway Driving Motion Decision Based on Optimal Control Theory

Chongqing University-Wei Yang, Zheng Ling, Yinong Li
  • Technical Paper
  • 2020-01-0130
To be published on 2020-04-14 by SAE International in United States
According to driving scenarios, intelligent vehicle is mainly applied on urban driving, highway driving and close zone driving, etc. As one of the most valuable developments, automated highway driving has great progress. This paper focuses on automated highway driving decision, and considering decision efficiency and feasibility, a hierarchical motion planning algorithm based on dynamic programming was proposed, and simultaneously, road coordinate transformation methods were developed to deal with complex road conditions. At first, all transportation user states are transformed into straight road coordinate to simplify modeling and planning, then a set of candidate paths with Bezier form was developed and with the help of obstacles motion prediction, the feasible target paths with collision-free were remains, and via comparing vehicle performance for feasible path, the optimal driving trajectory was generated. At last, the optimal control model was applied to obtain the motion parameters, which were regarded as the control target for lower level controller. A three-lane highway simulations was designed, and the results demonstrated that the proposed algorithm was valid to avoid obstacles with given speed,…
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The Resolution of 8th Order Whining Noise for a Battery Electric Vehicle

China FAW Group Co., Ltd.-Jingting Feng, Jianjiao Deng, Yingjie Liu, Hangsheng Hou, Ryusuke Oka
  • Technical Paper
  • 2020-01-1269
To be published on 2020-04-14 by SAE International in United States
With significant improvement in overall vehicle NVH performance in recent years, sound quality has increasingly become an important customer concern. In search of excellence in customer satisfaction with BEVs (Battery Electric Vehicles), optimizing e-motor noise is one of the most effective ways to improve the vehicle sound quality. This paper aims to resolve a whining noise issue from a PMSM (Permanent Magnet Synchronous Motor) during the development of a BEV program. The most critical order of the whining noise from an e-motor on market today is most likely the 48th order, which could be mitigated by implementing sound package material on the motor casing. In this work, however, the 8th order instead is found to be the most critical issue, and it is perceived as the whining noise in the frequency range under 600Hz. With such a low frequency content, sound package treatment has little effect. With subjective evaluation and test data analysis, it is found that the worst case is associated with the peak of the 8th order. The 8th order electromagnetic force is…
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A Study on the Development of the CPA (Centrifugal Pendulum Absorber)Reducing the Rattle & Booming Noise in the Manual Transmission Vehicle

Ukjin Kim
  • Technical Paper
  • 2020-01-0397
To be published on 2020-04-14 by SAE International in United States
In recent years, the automotive engine strategies are forced on downsizing and down speeding to enhance fuel economy and reduce the emission. These make torque increase significantly in order to improve the vehicle performance, especially in diesel engines. At this time, the torsional damper performs the most important role in the driveline NVH of the manual transmission system. The clutch disk with torsional dampers is not easy to be applicable to the high torque of low speed RPM range. And DMF with sufficient isolation of vibrations of driving system includes disadvantages of the expensive cost, delayed response, and engine NVH aspect deteriorated due to increase of angular acceleration of engine. This paper presents that the Centrifugal Pendulum Absorber (CPA) is applied to maximize the isolation and to compensate for the disadvantages of DMF and SMF system. Furthermore, CPA was developed for the first time in the world on SMF clutch discs in manual transmission.
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Development and Demonstration of a New Range-Extension Hybrid Powertrain Concept

Tongji University-Zhiyu Han, Zhenkuo Wu, Xiaojie Gao, Yongzheng Sun, Runyu Ni, Jian Feng, Jian zhong, Xinbo Chen, Zhiguo Zhao, Zhuoping Yu
  • Technical Paper
  • 2020-01-0845
To be published on 2020-04-14 by SAE International in United States
A new range-extension hybrid powertrain concept, namely the Tongji Extended-range Hybrid Technology (TJEHT) was developed and demonstrated in this study. This hybrid system is composed of a direct-injection gasoline engine, a traction motor, an Integrated Starter-Generator (ISG) motor, and a transmission. In addition, an electronically controlled clutch between the ISG motor and engine, and an electronically controlled synchronizer between the ISG motor and transmission are also employed in the transmission case. Hence, this system can provide six basic operating modes including the single-motor driving, dual-motor driving, serial driving, parallel driving, engine-only driving and regeneration mode depending on the engagement status of the clutch and synchronizer. Importantly, the unique dual-motor operation mode can improve vehicle acceleration performance and the overall operating efficiency. The hybrid system controls and energy management strategy based on equivalent fuel consumption minimization were developed and validated. The choice of an operating mode is optimized according to the drivers’ demand, actual vehicle state, operation conditions, and other boundary conditions. In this paper, the powertrain architecture and operating modes are firstly described. Secondly, the…