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Technical Paper

Design Optimization of Bicycle Wheel Hub Assembly for Automotive Applications

2022-03-29
2022-01-0262
The diminutive rolling resistance and wheel bearing drag characteristics of a bicycle wheel assembly makes it a lucrative choice of component in numerous 3-wheeled (3W) and 4-wheeled (4W) automotive applications. However, when a bicycle wheel is subjected to the loads encountered in such applications, complications pertaining to strength, durability and, performance are encountered. Since a bicycle wheel is intended to be arrested at either end of its axle, cantilever loading of the component as practiced in automotive applications diminishes the ability of the spindle to withstand longitudinal, and vertical forces encountered. Furthermore, while cornering on a bicycle, the maneuver of leaning in a corner significantly reduces the lateral stiffness requirement of the hub flanges. Therefore generic hub assemblies are designed without accounting for the action of lateral forces that are experienced at the hub with the wheel held vertical.
Technical Paper

Prediction and identification of vehicle rattle noise caused by shock absorbers

2022-03-29
2022-01-0304
A novel technology is proposed to predict vehicle rattle noise caused by shock absorbers. The model of shock absorber is developed by analyzing the force of moving parts, hydronic characteristic of valves and physical characteristic of oil. The model of mount, fixed between shock absorber and vehicle body, is developed with Maxwell method of combining series of spring and damping components. The characteristics of mount are measured under the specified frequency and amplitude conditions, the spring and damping coefficients of Maxwell model are identified using the measured data. The model of spring is developed by curve interpolation of measured data, considering the hysteresis properties of the real spring. The mass, wheel base etc. data of real vehicle are measured and the model of vehicle body is developed by Carsim using the measured data.
Technical Paper

Modelling of Off-Road Truck Tire-Rim Slip Using Finite Element Analysis

2022-03-29
2022-01-0882
Slip or relative rotation between the tire and rim is a significant concern for vehicle operation and wheel manufacturing since it leads to wheel imbalance and vibration as well as power losses. A slip situation typically occurs due to improper bead lubrication and mounting, irregularities in the bead seat and extreme loading conditions with high torques and low tire pressures. Currently, there are relatively few published studies on the tire-rim interface, and they mainly focus on topics such as the mounting process, load transfer, and friction modelling. This leaves a gap to explore the measurement and variation of gross tire slip under the dynamic conditions of a driven tire. In this paper, a previously developed and validated FEA truck tire model was modified to include a frictional contact surface between the tire and rim and then the slip ratio between the tire and rim was measured under different operating conditions.
Technical Paper

Experimental and Numerical Investigation of Rim Aerodynamics

2022-03-29
2022-01-0891
The automotive industry is facing new emission regulations, changing customer preferences and technology disruptions. All have in common, that external aerodynamics plays a crucial role to achieve emission limits, reduce fuel consumption and extend electric driving range. Probably the most challenging components in terms of numerical aerodynamic drag prediction are the wheels. Their contribution to the overall pressure distribution is significant, and the flow topology around the wheels is extremely complicated. Furthermore, deltas between different rim designs can be very small, normally in the range of only a few drag counts. Therefore, highly accurate numerical methods are needed to predict rim rankings and deltas. This paper presents experimental and numerical results of four different production rim designs, mounted to a modified production car.
Technical Paper

Trajectory following control for automated drifting of 4WID vehicles

2022-03-29
2022-01-0911
It is very significant for autonomous vehicles to have the ability to operate beyond the stable handling limits, which plays a vital role in vehicles’ active safety and enhances riding and driving pleasure. For traditional vehicles, it is rather difficult to control the longitudinal speed, side-slip angle and yaw rate simultaneously when drifting along a given trajectory because they are under-actuated. Nevertheless, for a 4-wheel-independent-drive (4WID) vehicle, it is possible and controllable thanks to its over-actuated characteristics. This article designs a trajectory following control strategy for automated drifting of 4WID vehicles. First, a double-track 7 degree of freedom (7DOF) vehicle dynamic model with actuator redundancy is established, which incorporates longitudinal and lateral load transfer and considers nonlinear tire models. The controller which proposes a hierarchical architecture is then designed.
Technical Paper

Active control of Camber and Toe angles to improve vehicle Ride Comfort

2022-03-29
2022-01-0920
This paper is part of the European OWHEEL project. It proposes a method to improve the comfort of a vehicle by adaptively controlling the Camber and Toe angles of a rear suspension. The purpose is achieved through two actuators for each wheel, one that allows to change the Camber angle and the other the Toe angle. The control action is dynamically determined based on the error between the reference angle and the actual angles. The reference angles are not fixed over time but dynamically vary during the manoeuvre. The references vary with the aim of maintaining a Camber angle close to zero and a Toe angle that follows the trajectory of the vehicle during the curve. This improves the contact of the tire with the road. This solution allows the control system to be used flexibly for the different types of manoeuvres that the vehicle could perform. An experimentally validated sports vehicle was used to carry out the simulations. The original rear suspension is a Trailing-arm suspension.
Technical Paper

Integrated Wheel Assembly Designing and optimization for BAJA SAE ATV

2022-03-29
2022-01-0795
The conventional Wheel assembly is optimized using Stub and Hub integration by researching and evaluating new assembly designs, Material selection using Charpy impact test on different materials (EN24, 20MNR5, EN36) with different hardening processes (through hardening, Carburizing) are evaluated for the best combination of material and type of hardening which absorbs highest impact energy, which further evaluated for different types of brittle and ductile failure on those specimens, Component designing is performed considering various boundary condition evaluated for BAJA SAE ATV which includes Bump force due to hill fall down, Tension/Compression generation in case of improper landing on wheels, Torsion transfer through axle and Lateral forces due to centrifugal forces were used for design calculation and then FEA is used for Design validation. Finite model is generated in Hypermesh using various Meshing techniques considering rotating symmetry for achieving good quality criteria.
Technical Paper

Lap Time Optimization and Path Following Control for 4WS & 4WID Autonomous Vehicle

2022-03-29
2022-01-0376
In contrast to a normal vehicle, a 4-wheel steer (4WS) and 4-wheel independent drive (4WID) vehicle provides more flexibilities in vehicle dynamics control and better handling performance, since both the steer angle and drive torque of each wheel can be controlled. However, for motorsports, how much lap time can be improved with such a vehicle is a problem undiscussed. So, this paper focuses on the racing line optimization and lap time improvement for a 4WS &4WID vehicle. First, we optimize the racing line and lap time of three given circuits with the genetic algorithm (GA) and interior-point method, and several objective functions are compared. Next, to evaluate the lap time improvement of 4WS & 4WID, a detailed vehicle dynamic model of our 4WS & 4WID platform vehicle is built in Carsim. To follow the racing line, a path following controller which contains a PID speed controller and a model predictive control (MPC) yaw rate controller is built.
Technical Paper

Mobility Boundaries for the Wheel Normal Reaction

2022-03-29
2022-01-0360
When a vehicle moves over uneven ground, motion of the sprung and unsprung masses causes dynamic shifting in the load transmitted to the ground, making the normal reaction in the tire-soil patch a continuously changing wheel parameter that may affect vehicle performance. At high loads, sinkage of the wheel can become high as the wheel digs into the soil. At low loads, the wheel can have difficulty acquiring sufficient traction. Additionally, steerability of the wheel can be diminished at very low loads. Controlling the damping forces in the suspension that is usually used to improve ride quality and stabilize motion of the sprung mass can result in an increase in the dynamic variation of the wheel normal reaction and cause vehicle performance deterioration. In this paper, a method is developed to establish boundary constraints on the dynamic normal reaction to maintain reasonable tire-terrain mobility characteristics.
Technical Paper

A Hybrid Approach Combining LSTM Networks and Kinematic Rules for Vehicle Velocity Estimation

2022-03-29
2022-01-0157
Vehicle speeds, in both longitudinal and lateral directions, are vital signals for vehicular electronic control systems. In in-wheel motor-driven vehicles (IMDVs), because there is no slave wheel that can be used for reference, it becomes more challenging to conduct speed estimation, especially when all wheels turn to slip. To reduce the dependence of speed estimation on physical plant parameters and environment perception, in this work, we develop a new method which estimates the longitudinal and lateral velocities of an IMDV by using the kinematic model with Kalman filter. For longitudinal velocity measurement, we propose an integrated approach combing the kinematic rules and double Long-Short Term Memory (LSTM) networks to obtain a reliable estimation. More specifically, when there is at least one effective driven wheel available, that is, no-slip happening, the longitudinal velocity can be derived by using the average of those effective wheels’ rotational speeds.
Technical Paper

Loading Classification for Fatigue Design applied to Automotive Time-Series

2022-03-29
2022-01-0254
This study focuses on variable amplitude loadings applied to automotive chassis parts experiencing carmaker’s specific proving grounds. They are measured with respect to time at the wheel centres and composed of the six forces and torques at each wheel, within the standard vehicle reference frame. In the scope of high cycle fatigue, the loadings considered are supposedly acting under the structure yield stress. Among the loadings encountered during the vehicle lifetime, two classes stand out: • Driven Road: loads measured during the vehicle manoeuvre (cornering, braking). • Random Road: random loads mainly coming from the road asperity. To separate both effects, a frequency decomposition method is proposed before applying any lifetime assessment methods. The usual rainflow counting method is applied to the Driven Road signal. These loadings, depending on the vehicle dynamic, are time-correlated. Thus, the load spectra is set only thanks to the vehicle accelerations time-measurement.
Technical Paper

Virtual Driveline Concept-based Maneuverability Control of a Skid-Steering UGV with Individually Driven Wheels

2022-03-29
2022-01-0366
In the absence of a physical driveline between the wheels powered by individual electric motors, in this paper, a concept of the virtual driveline system was applied to a small skid-steering unmanned ground vehicle (UGV) for the purpose of controlling its maneuverability, i.e., for fulfilling desired maneuvers in terrain zones constrained by natural and man-made objects. The virtual driveline concept supposes that the UGV driving wheels are connected via a virtual driveline that is a computational code to manage the power split among the wheels by using characteristics of a mechanical driveline system. The kinematic discrepancy factor (KDF) as a mechanical driveline characteristic is utilized to mathematically link the angular velocities and the drive torques of the electrically driven wheels.
Technical Paper

Vehicle Feature Recognition Method Based on Image Semantic Segmentation

2022-03-29
2022-01-0144
In the process of truck overload and over-limit detection, it is necessary to detect the characteristics of the vehicle's size, type, and wheel number. In addition, in some vehicle vision-based load recognition systems, the vehicle load can be calculated by detecting the vibration frequency of specific parts of the vehicle or the change in the length of the suspension during the vehicle's forward process. Therefore, it is essential to quickly and accurately identify vehicle features through the camera. This paper proposes a vehicle feature recognition method based on image semantic segmentation and Python, which can identify the length, height, number of wheels and vibration frequency at specific parts of the vehicle based on the vehicle driving video captured by the roadside camera.
Technical Paper

Electric Vehicle Corner Architecture: Driving Comfort Evaluation Using Objective Metrics

2022-03-29
2022-01-0921
The transportation sector now faces several technological and societal challenges; the most urgent one is a shift to carbon-neutral mobility. One of the most efficient ways to reach this goal is car electrification. Vehicle corner architecture with an in-wheel motor is a promising stage of technological development for a new generation of electric vehicles. The state of art analysis indicates that a higher degree of integration between powertrain and chassis and the shift towards corner solution promises improved performances regarding new vehicle architecture design, energy efficiency, vehicle stability, reducing the overall system's weight. However, in-wheel mounted electric motor significantly increases unsprung vehicle mass; therefore, some undesirable impact on chassis loads and driving comfort occur.
Technical Paper

Control strategy for ISD suspension considering dynamic vibration absorber of wheel motor

2022-03-29
2022-01-0285
Vehicles driven by in-wheel motors have the advantages of compact structure and high transmission efficiency, which is one of the most ideal energy-saving, environmentally friendly and safe driving forms in the future. However, the addition of the in-wheel motor significantly increases the unsprung mass of the vehicle, resulting in a decrease in the mass ratio of the vehicle body to the wheel, which will deteriorate the ride comfort and safety of the vehicle. To improve the vibration performance of in-wheel motor vehicles, a semi-active inerter-spring-damping(ISD) suspension based on in-wheel motor vibration absorption is proposed in this paper. Firstly, mounting elements are applied to the wheel to provide elastic isolation between the in-wheel motors and the tyre, which converts the in-wheel motor mass into a vibration absorber to suppress the high-frequency vibration of the unsprung mass.
Technical Paper

On-board estimation of road adhesion coefficient based on ANFIS and UKF

2022-03-29
2022-01-0297
The road adhesion coefficient has a great impact on the performance of vehicle tires, which in turn affects vehicle safety and stability. A low coefficient of adhesion can significantly reduce the tire's traction limit. Therefore, the measurement of the coefficient is much helpful for automated vehicle control and stability control. Considering that the road adhesion coefficient is an inherent parameter of the road and it cannot be known directly from the information of the on-vehicle sensors. The novelty of this paper is to construct a road adhesion coefficient observer which considers the noise of sensors and measures the unknown state variable by the trained neural network. A Butterworth filter and Adaptive Neural Fuzzy Interference System (ANFIS) are combined to provide the lateral and longitudinal velocity which cannot be measured by regular sensors.
Technical Paper

Vehicle Energy Dissipation during Curb Traversal

2022-01-04
2022-01-5002
Previously published vehicle curb traversal test data for 122 full-scale vehicle tests were examined to evaluate the change in a vehicle’s kinetic energy during traversal of a roadside curb while rolling on its wheels. This change in energy was correlated to test parameters including the ratio of tire radius to curb height, vehicle approach angle, and vehicle speed at curb contact. Various regression relationships quantifying the change in vehicle kinetic energy during curb traversal versus the above parameters were examined, wherein the kinetic energy change was expressed as an equivalent energy speed (EES) in which the energy change was normalized using the test vehicle’s mass. No statistical significance was observed in relations involving EES as a function of parameters which included approach angle and the ratio of tire radius to curb height.
Technical Paper

Path Tracking Control of Vehicles Based on Adaptive Model Prediction Control

2021-12-14
2021-01-7034
In order to improve the path tracking accuracy of driverless vehicles at different speed, a fuzzy adaptive model prediction control method was proposed to adjust constant predictive horizon of MPC. Based on the MPC method of 3-DOF vehicle dynamics model, prediction horizon and weight coefficient of the MPC controller could be varied in real time according to the speed and road curvature. With the desired path as the target, the front wheel angle was changed to achieve path tracking. Simulation analysis was performed under the CarSim/Simulink co-simulation environment. Simulation results show that under the condition of satisfying ride comfort and stability of vehicle, the tracking error of the proposed method in the path tracking control is reduced by 30.0%, 29.9% and 14.6% at 36km/h, 72km/h and 108km/h, respectively, which are helpful to path tracking control.
Technical Paper

Research on Locked Wheel Protection Function of Aircraft Brake System

2021-10-11
2021-01-1269
Locked wheel protection is an important part of antiskid control for aircraft brake control system. Locked wheel protection compares the wheel speed of two or more wheels, if one of the wheels is too slow, locked wheel protection releases the brake pressure on the slow wheel. This work aims to study the control logic for locked wheel protection. Locked wheel protection control logic consists of 3 key factors: paired wheels, active threshold and inhibit velocity. Focus on comparison different options of these 3 factors, all aspects of control logic for locked wheel protection had been expounded in this study. Simulation and calculation analysis is applied for different locked wheel strategies to evaluate the effect. One conclusion is that the greatest wheel speed of the wheel under control shall be set as a reference speed for locked wheel protection. This study provide the basis to design a proper locked wheel protection function of aircraft brake control system.
Technical Paper

Measurement of Particle Dynamics on the Real Vehicle in Different Driving Scenarios with Swarm Sensors

2021-10-11
2021-01-1299
Due to the increase in public attention in the analysis of non-exhaust emission sources because of the growing electrification of vehicles, measurements have been performed in recent years to develop a consistent test standard. In particular, the consideration of tyre and brake abrasion took a predominant position due to the small particle sizes. With measurements under controlled and laboratory-like athmosphere, for example for brakes on dynamometers, attempts have been made to create a uniform test standard according to the Worldwide harmonized Light vehicles Test Procedure (WLTP). However, a transfer to the real driving environment is not yet feasible because of many external disturbance variables, such as the wheel housing or atmospheric variables. Typical reference measurement sensors in the vehicle are only suitable to a limited extent for mobile operation due to their size and the necessary measurement infrastructure.
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