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Technical Paper

Research on the Control Strategy of Trailer Tracking Tractor for Articulated Heavy Vehicles

2019-11-04
2019-01-5054
The purpose of this paper is to improve the path-following capability and high-speed lateral stability of the articulated heavy vehicles (AHVs). The six-axle heavy articulated vehicle was taken as the research object, in order to simplify the control design, the three-axle trailer of the articulated vehicles was simplified to a single-axle trailer. The Newton's second law was applied to the tractor unit and the single-axle trailer unit respectively, a three-degree-of-freedom vehicle yaw plane model was established, and its state space equation was derived. The trailer steering controller was designed by linear quadratic regulator (LQR) technique. At the same time, the optimal index function was determined by combining the vehicle state variables, and the optimal control input was obtained by using the algebraic Riccati equation.
Technical Paper

Research on Control Algorithm of Active Steering Control Based on the Driver Intention

2019-11-04
2019-01-5064
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.
Technical Paper

Lightweight Design and Multi-Objective Optimization for a Lower Control Arm Considering Multi-Disciplinary Constraint Condition

2019-04-02
2019-01-0822
The requirement for low emissions and better vehicle performance has led to the demand for lightweight vehicle structures. Two new lightweight methods of design and optimization for the lower control arm were proposed in this research to improve the effectiveness of the traditional lightweight method. Prior to the two lightweight design and optimization methods, the static performance, including strength, stiffness and mode, and fatigue performance for the lower control arm were analyzed and they provided constraints for subsequent design and optimization. The first method of lightweight design and optimization was integrated application of topography optimization, size optimization, shape optimization and free shape optimization for the control arm. Topography optimization was first applied to find the optimal distribution form of reinforcement rib for the lower control arm. Size optimization was then applied in this study to optimize the plate thickness.
Technical Paper

CATARC New Type Drivetrain NVH Test Facility

2019-04-02
2019-01-0788
A vehicle’s NVH performance has a significant impact on the user experience of the driver and passengers. About one-third of the vehicle complaints are related to NVH performance. As the core component of the vehicle, the drivetrain’s NVH characteristics have a significant impact on vehicle comfort. How to reliably and stably reproduce the specific condition of the whole vehicle through the test method, and obtain the highly consistent objective data for analyzing and improving the NVH characteristics of the drivetrain is of great significance in engineering. For this purpose, China Automotive Technology Research Center Co., Ltd. (CATARC) designed and built a new type drivetrain NVH test facility, which consists of five dynamometers, and can carry horizontal/vertical, front/rear drive or four-wheel drive structures including powertrain, transmission, and rear axle, or even a whole vehicle.
Technical Paper

Numerical Analysis of Underbody Diffusers with Different Angles and Channels

2019-04-02
2019-01-0668
The underbody diffusers are used widely in race cars to improve the flow field structure at the bottom of the car and provide enough downforce. In recent years, passenger cars have begun to use bottom diffuser to improve aerodynamic characteristics, so as to reduce drag and increase downforce. In this paper, the aerodynamic characteristics of the bus with different underbody diffuser angles and channel numbers are studied by numerical simulation analysis. Firstly, the aerodynamics of the bus under different diffuser inlet and outlet angles are studied, and then an optimal inlet and outlet angle is determined based on the simulation results. Then, using this angle as a constant, the 2, 3, and 4 channel numbers were chosen as the diffuser channel variables to study the influence of the multiple-channel diffusers on the aerodynamic drag of the vehicle.
Technical Paper

Performance Analysis on 3D Printed Beak-Shaped Automotive Tail Fin Filled with Honeycomb Cellular Structure

2019-04-02
2019-01-0712
The concept of “bionic design” has driven the developments of automotive design. In this paper, a novel beak-shaped automotive tail fin with honeycomb cellular structure is proposed based on the idea of “bionic design”. Beak-shaped appearance is utilized to meet the requirement of aerodynamics performance, inner honeycomb cellular structure is filled to achieve more lightweight space. This paper starts from the establishment of three dimensional (3D) model based on the real characteristics of sparrow’s beak. On this basis, aerodynamic performances of novel beak-shaped tail fin and conventional shark tail fin are analyzed by experiment. Finally, the stiffness and modal analyses of solid beak-shaped tail fin and honeycomb beak-shaped tail fin are carried out respectively. The results indicate that the deformation of solid beak-shaped tail fin and honeycomb beak-shaped tail fin satisfy the basic requirements.
Technical Paper

Lightweight Design of CFRP Automobile Tailgate Based on Multi-Step Optimization

2019-04-02
2019-01-1103
As a critical part of auto-body, the design of tailgate not only affects the beauty, usability and safety of automobile, but also involves more and more issues about environmental protection and energy saving. Hence, it is of vital importance to investigate lightweight of tailgate. This paper mainly focuses on lightweight design of CFRP tailgate based on conventional SUV metal tailgate, which can be realized under the condition of meeting requirements of stiffness, modal and manufacturing with the adoption of multi-step optimization method. To start with, finite element (FE) model of metal tailgate is established. Meanwhile, the stiffness and modal analyses, including bending stiffness, torsional stiffness, lateral stiffness, vertical stiffness and free modal are set up. Then, the structural performances of metal tailgate are analyzed, and the topology optimization of CFRP tailgate is performed.
Technical Paper

Research on Multi-Vehicle Coordinated Lane Change of Connected and Automated Vehicles on the Highway

2019-04-02
2019-01-0678
With the rapid development of modern economy and society, traffic congestion has become an increasingly serious problem. Vehicle cooperative driving can alleviate traffic congestion and improve road traffic capacity. Compare with vehicle separate control, cooperative driving combines various vehicle systems, and highly integrates information on obstacle location, vehicle status and driving intention. Then the controller uniformly issues instructions to ensure the orderly driving of the platoon. In the cooperative driving platoon, the displacement difference and the speed difference between vehicles have a certain relationship, which reduces the possibility of traffic accidents and then improves the safety of driving. In the process of cooperative driving, if there are multiple vehicles whose speeds don’t meet the current lane requirements, or if there are obstacles ahead, multi-vehicle lane change measures must be taken.
Technical Paper

Aeroelastic Response and Structural Improvement for Heavy-Duty Truck Cab Deflectors

2019-01-14
2019-01-5004
Numerical simulations on the fluid-structure interaction were conducted using commercial software STAR-CCM+ and ABAQUS. The aeroelastic responses of a deflector under several different working conditions were simulated utilizing finite volume and finite element methods to investigate the aeroelastic problem of automotive deflectors. Results showed that the structural response of a top deflector is minimal under the influence of aerodynamics given its large structural stiffness. The size of the top deflector was optimised by using thickness as a variable. The volume and quality of the top deflector were significantly reduced, and its lightweight performance was improved to satisfy the stiffness performance requirement. The vibration of a side deflector structure was mainly induced by the turbulence on the structure surface. The amplitude of vibration was small and the vibration gradually converged in a few seconds without obvious regularity.
Technical Paper

Deterioration Characteristic of Catalyzed DPF Applied on Diesel Truck Durable Ageing

2018-09-10
2018-01-1701
In this paper, it was researched the degradation characteristics of catalytic performance of three kinds of DPFs (C1, C2 and C3, with precious metal concentrations being 15, 25 and 35 g/ft3 respectively) after diesel truck aging. It is found out that the crystallinity of three kinds of DPF samples (Used) in full vehicle aging was higher than that of fresh samples (Fresh) and aged samples (Aged) in the laboratory. Compared with Fresh samples, the concentration of Pt atom in precious metal on the surface of Aged and Used samples tends to decrease in most cases. Activities to CO and C3H8 of Aged and Used samples of three kinds of DPFs had all been degraded, and activity degradation showed a substantial correlation with concentration reduction rate of precious metal on the carrier surface. NO2 productivity of Used samples all rose. Crystallinity of DPF samples after full vehicle aging in Inlet, Middle and Outlet areas successively increased.
Technical Paper

Personalized Eco-Driving for Intelligent Electric Vehicles

2018-08-07
2018-01-1625
Minimum energy consumption with maximum comfort driving experience define the ideal human mobility. Recent technological advances in most Advanced Driver Assistance Systems (ADAS) on electric vehicles not only present a significant opportunity for automated eco-driving but also enhance the safety and comfort level. Understanding driving styles that make the systems more human-like or personalized for ADAS is the key to improve the system comfort. This research focuses on the personalized and green adaptive cruise control for intelligent electric vehicle, which is also known to be MyEco-ACC. MyEco-ACC is based on the optimization of regenerative braking and typical driving styles. Firstly, a driving style model is abstracted as a Hammerstein model and its key parameters vary with different driving styles. Secondly, the regenerative braking system characteristics for the electric vehicle equipped with 4-wheel hub motors are analyzed and braking force distribution strategy is designed.
Technical Paper

Analysis of Vehicle Steering Stability of Nonlinear Four Wheel Steering Based on Sliding Mode Control

2018-08-07
2018-01-1593
Steering movement is the most basic movement of the vehicle, in the car driving process, the driver through the steering wheel has always been to control the direction of the car, in order to achieve their own driving intention. Four Wheel Steering (4WS) is an advanced vehicle control technique which can markedly improve vehicle steering characteristics. Compared with traditional front wheel steering vehicles, 4WS vehicles can steer the front wheels and the rear wheels individually for cornering, according to the vehicle motion states such as the information of vehicle speed, yaw velocity and lateral acceleration. Therefore, 4WS can enhance the handling stability and improve the active safety for vehicles.
Technical Paper

Aerodynamics of Open Wheel Racing Car in Pitching Position

2018-04-03
2018-01-0729
Formula One (F1) racing cars are often running at high-speed with the pitching angle changing frequently due to road conditions. These pitching angle changes result in changes to the car’s aerodynamic characteristics that will directly affect handling stability and other performance factors including safety. This paper takes a F1 racing car as the model; the influence of the change of pitching angle on aerodynamic drag force and lift force are investigated. CFD code-PowerFLOW based LBM is used to simulate the aerodynamic characteristics with different pitching angles. The distribution of aerodynamic coefficients, velocity and pressure in the flow field are obtained; and the differences between different pitching angles were analyzed. The results show that as the pitching angle increases, the drag force increases and the lift force decreases. The down-force of the car is mainly supplied by the front wing and the rear wing.
Technical Paper

Unsteady Flow Control and Wind Noise Reduction of Side-View Mirror

2018-04-03
2018-01-0744
It aims to study the unsteady flow characteristic of the side-view mirror wake field, and reduce the wind noise by means of unsteady flow control. In this paper, the PIV test in a wind tunnel is used to capture the unsteady flow in the wake field of the side-view mirror, which is used to verify the accuracy of the steady simulation method with RANS after being averaged. Then LES turbulence model is used to obtain the wind noise, and the unsteady flow characteristic like vortex shedding of the side-view mirror is studied. The results show that, in the wake of the side-view mirror, there is a vortex pair similar to Karman Vortex Street. In both horizontal and vertical sections, these two vortexes are respectively separated from the upper and lower edges of the side-view mirror. Accompanied by a significantly uncertain periodic shedding, they continue to extend back until dissipating.
Technical Paper

Dynamic Characteristics Analysis of an Ambulance with Hydraulically Interconnected Suspension System

2018-04-03
2018-01-0815
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.
Technical Paper

Research on the Dynamic Integration Control for Distributed-Traction Electric Vehicle with Four-Wheel-Distributed Steering System

2018-04-03
2018-01-0814
With rapid development of the automobile industry and the growing maturity of the automotive electronic technologies, the distributed-traction electric vehicle with four-wheel-distributed steering/braking/traction systems is regarded as an important development direction. With its unique chassis structure, it is the ideal benchmark platform used to evaluate active safety systems. The distributed-traction electric vehicle with four-wheel-distributed steering system is essentially full drive-by-wire vehicle. With its flexible chassis layout and high control degrees-of-freedom, the full drive-by-wire electric vehicle acted as a kind of redundant system is an ideal platform for the research of integrated control. In this treatise, the longitudinal dynamics of the electric vehicle as well as its lateral and yaw motions are controlled simultaneously.
Technical Paper

Fuzzy PID Based Optimization of Starting Control for AMT Clutch of Heavy-duty Trucks

2018-04-03
2018-01-1166
Starting control has become a troublesome issue in the developing field of the control system for heavy-duty trucks, due to the complexity of vehicle driving and the variability of driver's intention. The too fast clutch engagement may result in serious impact, influence on the comfort and fatigue life, and even the engine flameout, while the too slow clutch engagement may lead to long time of friction, the increased temperature, and accelerated wear of friction pair, as well as influence on the power performance and fatigue life[1]. Therefore, the key technique of starting control is clutch engagement control, for which the fuzzy PID based optimization of starting control for AMT clutch is proposed, with the pneumatic AMT clutch of heavy-duty trucks as the research object.
Technical Paper

Research on Steering Performance of Steer-By- Wire Vehicle

2018-04-03
2018-01-0823
With the popularity of electrification and driver assistance systems on vehicle dynamics and controls, the steering performance of the vehicle put forward higher requirements. Thus, the steer-by-wire technology is becoming particularly important. Through specific control algorithm, the steer-by-wire system electronic control unit can receive signals from other sensors on the vehicle, realize the personalized vehicle dynamics control on the basis of understanding the driver’s intention, and grasp the vehicle movement state. At the same time, to make these driver assistance systems better cooperate with human drivers, reduce system frequent false warning, full consideration of mutual adaptation for the systems and the driver’s characteristics is critical. This paper focuses on the steering performance of steer-by-wire vehicle. Feature parameters are obtained from the virtual turning experiment designed on the driving simulator experimental platform.
Technical Paper

Modelling and Validation for an Electro-Hydraulic Braking System Equipped with the Electro-Mechanical Booster

2018-04-03
2018-01-0828
The intelligent and electric vehicles are the future of vehicle technique. The development of intelligent and electric vehicles also promotes new requirements to many traditional chassis subsystems, including traditional braking system equipped with vacuum boosters. The Electro-Mechanical Booster is an applicable substitute of traditional vacuum booster for future intelligent and electric vehicles. It is independent of engine vacuum source, and can be combined with electric regenerative braking. A complete system model is necessary for system analysis and algorithm developing. For this purpose, the modeling of electro-hydraulic braking system is necessary. In this paper, a detailed electro-hydraulic braking system model is studied. The system consists of an electro-mechanical booster and hydraulic braking system. The electro-mechanical booster which mainly contains a permanent magnet synchronous motor (PMSM) and a set of transmission mechanism is the critical component.
Technical Paper

Lateral Dynamics and Suspension Tuning for a Two-Axle Bus Fitted with Roll-Resistant Hydraulically Interconnected Suspension

2018-04-03
2018-01-0831
In this paper, a new roll-plane hydraulically interconnected suspension (HIS) system is proposed to enhance the roll and lateral dynamics of a two-axle bus. It is well-known that the suspension tuning is of great importance in the design process and has also been explored in a number of studies, while only minimal efforts have been made for suspension tuning for the newly proposed HIS system especially considering lateral stability. This study aims to explore lateral dynamics and suspension tuning of a two-axle bus with HIS system, which could also provide valuable information for roll dynamics analysis. Based on a ten-DOFs lumped-mass full-car model of a bus either integrating transient mechanical-hydraulic model for HIS or the traditional suspension components, three newly promoted parameters of HIS system are defined and analyzed-namely the total roll stiffness (TRS), roll stiffness distribution ratio (RSDR) and roll-plane damping (RPD).
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