Refine Your Search

Topic

Search Results

Viewing 1 to 19 of 19
Technical Paper

Virtual Set-up of a Racing Engine for the Optimization of Lap Performance through a Comprehensive Engine-Vehicle-Driver Model

2011-09-11
2011-24-0141
In Motorsports the understanding of the real engine performance within a complete circuit lap is a crucial topic. On the basis of the telemetry data the engineers are able to monitor this performance and try to adapt the engine to the vehicle's and race track's characteristics and driver's needs. However, quite often the telemetry is the sole analysis instrument for the Engine-Vehicle-Driver (EVD) system and it has no prediction capability. The engine optimization for best lap-time or best fuel economy is therefore a topic which is not trivial to solve, without the aid of suitable, reliable and predictive engineering tools. A complete EVD model was therefore built in a GT-SUITE™ environment for a Motorsport racing car (STCC-VW-Scirocco) equipped with a Compressed Natural Gas (CNG) turbocharged S.I. engine and calibrated on the basis of telemetry and test bench data.
Technical Paper

Vehicle Side Slip and Roll Angle Estimation

2016-04-05
2016-01-1654
Vehicle dynamics estimation has been the subject of study for some years now. If on-board vehicle control systems can be provided with information such as side slip angle, lateral force etc. then stability of the vehicle can be improved. To estimate these dynamic variables different observers have been used e.g., sliding mode, fuzzy logic, neural networks etc. In this article the authors propose an extended Kalman filter to estimate vehicle side slip angle. Roll angle is estimated using vertical loads as input. First, a linear Kalman filter is used to filter out the vertical forces and estimate roll angle. This information is then used to estimate the vehicle side slip angle. To take into account the nonlinearities concerning lateral vehicle dynamics, Pacejka magic formula is used to model lateral forces. Estimated results are then compared with simulations, showing good accuracy.
Technical Paper

Vehicle Dynamics Simulation to Develop an Active Roll Control System

2007-04-16
2007-01-0828
Active Roll Control (ARC) is one of the most promising active systems to improve vehicle comfort and handling. This paper describes the simulation based procedure adopted to conceive a double-channel Active Roll Control system, characterized by the hydraulic actuation of the stabilizer bars of a sedan. The first part of the paper presents the vehicle model adopted for this activity. It is Base Model Simulator (BMS), the 14 Degrees-of-Freedom vehicle model by Politecnico di Torino. It was validated through road tests. Then the paper describes the development of the control algorithm adopted to improve the roll dynamics of the vehicle. The implemented control algorithm is characterized by a first subsystem, capable of obtaining the desired values of body roll angle as a function of lateral acceleration during semi-stationary maneuvers.
Journal Article

Sideslip Angle Estimation of a Formula SAE Racing Vehicle

2016-04-05
2016-01-1662
A method for estimating the sideslip angle of a Formula SAE vehicle with torque vectoring is presented. Torque vectoring introduces large tire longitudinal forces which lead to a reduction of the tire lateral forces. A novel tire model is utilized to represent this reduction of the lateral forces. The estimation is realized using an extended Kalman filter which takes in standard sensor measurements. The developed algorithm is tested by simulating slalom and figure eight maneuvers on a validated VI-CarRealTime vehicle model. Results indicate that the algorithm is able to estimate the sideslip angle of the vehicle reliably on a high friction surface track.
Technical Paper

Shock Absorber Modeling and Experimental Testing

2007-04-16
2007-01-0855
Simulation is becoming the fundamental tool to design the main components of a vehicle. The paper describes the shock absorber model which was implemented by the Vehicle Dynamics Research Team of Politecnico di Torino. It is a modular model which can be adopted both for mono-tube and twin-tube shock absorbers. It can be used at different levels of approximation, as a function of the kind of user and his/her targets. The main data which have to be inserted in the model are fluid properties, the basic dimensions of the component and the characteristics of the orifices of the shock absorber. An experimental test bench was conceived to obtain the diagrams plotting flow rate through an orifice of a shock absorber versus the pressure drop between input and output ports. The test rig and the procedure to perform the experimental tests and insert the results in the shock absorber model are described in detail.
Technical Paper

Road to Virtual Tuning: New Physical Lump Model and Test Protocol to Support Damper Tuning in Hyundai Motor Europe Technical Center

2019-04-02
2019-01-0855
Vehicle dynamics is a fundamental part of vehicle performance. It combines functional requirements (i.e. road safety) with emotional content (“fun to drive”, “comfort”): this balance is what characterizes the car manufacturer (OEM) driving DNA. To reach the customer requirements on Ride & Handling, integration of CAE and testing is mandatory. Beside of cutting costs and time, simulation helps to break down vehicle requirements to component level. On chassis, the damper is the most important component, contributing to define the character of the vehicle, and it is defined late, during tuning, mainly by experienced drivers. Usually 1D lookup tables Force vs. Velocity, generated from tests like the standard VDA, are not able to describe the full behavior of the damper: different dampers display the same Force vs. Velocity curve but they can give different feeling to the driver.
Technical Paper

Performance Optimization for the XAM Hybrid Electric Vehicle Prototype

2012-04-16
2012-01-0773
Given the ever-increasing concern about environmental issues, the automotive industry is focusing on the development of innovative technologies that allow reduction of gas emissions and fuel consumption. Over the last few years, Hybrid Electric Vehicles (HEV) and Fuel Cell Vehicles have been developed as the most promising alternative solutions for many car manufacturers. Although fuel cells are considered as the best technology to have zero emission, the impact on infrastructure for a large-scale deployment is not yet solved. For this reason, HEV represent a valid shorter-term alternative that guarantees drastic emissions reduction and reduced fuel consumption with a much lower infrastructural impact. This paper reports the results obtained by the optimization of the emissions and fuel performances of a hybrid electric city vehicle for urban transportation named XAM (eXtreme Automotive Mobility). In order to optimize these performances, a 1D model of the vehicle has been created.
Technical Paper

Pem Fuel Cell Performance Under Particular Operating Conditions Causing the Production of Liquid Water: A Morphing on Bipolar Plate's Channels Approach

2011-04-12
2011-01-1349
A fuel-cell-based system's performance is mainly identified in the overall efficiency, strongly depending on the amount of power losses due to auxiliary devices to supply. In such a situation, everything that causes either a decrease of the available power output or an increment of auxiliary losses would determine a sensible overall efficiency reduction.
Technical Paper

Linear Approach to ESP Control Logic Design

2006-04-03
2006-01-1017
An Electronic Stability Program (ESP) control logic is designed. It is devoted to stabilize vehicle during cornering maneuvers. The aim of the activity is to obtain a feed forward (FF) control structure, capable of better performance than a previously developed closed loop one. The efficiency of ESP intervention is determined observing yaw rate peak reduction and oscillation damping time during step steer maneuver, together with vehicle side slip angle containment and longitudinal speed loss. A single track vehicle model is used to obtain two transfer functions describing vehicle and active system behavior. A third transfer function is derived from active vehicle frequency response that is the designer's target. The interaction between the transfer functions permits to design a feed forward control logic, which is then merged in a closed loop control structure in order to ensure fail safe conditions and control robustness.
Technical Paper

Improvement of Lap-Time of a Rear Wheel Drive Electric Racing Vehicle by a Novel Motor Torque Control Strategy

2017-03-28
2017-01-0509
This paper presents a novel strategy for the control of the motor torques of a rear wheel drive electric vehicle with the objective of improving the lap time of the vehicle around a racetrack. The control strategy is based upon increasing the size of the friction circle by implementing torque vectoring and tire slip control. A two-level nested control strategy is used for the motor torque control. While the outer level is responsible for computing the desired corrective torque vectoring yaw moment, the inner level controls the motor torques to realize the desired corrective torque vectoring yaw moment while simultaneously controlling the wheel longitudinal slip. The performance of the developed controller is analyzed by simulating laps around a racetrack with a non-linear multi-body vehicle model and a professional human racing driver controller setting.
Technical Paper

Electro-Hydraulic Braking System Modelling and Simulation

2003-10-19
2003-01-3336
The first step toward a braking system ‘by wire’ is Electro-Hydraulic Braking System (EHB). The paper describes a method to evaluate through virtual experimentation the actual improvement in vehicle behaviour, from the point of view of both handling and comfort, including also pedal feeling, due to EHB. The first step consisted in modelling the hydraulic unit, comprehensive of sensors. Then it was conceived a control logic devoted to medium-low intensity braking manoeuvres, without ABS intervention, to determine an optimal braking force distribution and pedal feeling depending on the manoeuvre. A failsafe strategy, complete of on board diagnosis, to prevent dangerous system behaviour in the eventuality of a component failure was carried out and tested. Finally, EHB wheel pressure sensors were used to improve both ABS performance, increasing the adherence estimation, and Vehicle Dynamics Control (VDC) performance, through a more precise actuation.
Technical Paper

Effective Vehicle Sideslip Angle Estimation using DVS Technology

2014-04-01
2014-01-0084
The vehicle sideslip angle is one of the most important variables for evaluating vehicle dynamics. The potential value of such a variable for obtaining significant improvements over current stability control systems is widely recognized. However, its direct measurement requires the use of complex and expensive devices which cannot be used in production cars. Large research efforts has been devoted to the problem of estimating the sideslip angle from other variables currently measured by standard Electronic Stability Control (ESC) sensors. However, at the best of author's knowledge, until now no application to production cars is known. In this paper, a new sideslip angle estimation technology is presented.
Technical Paper

Differentials Modeling for Four Wheels Drive

2006-04-03
2006-01-0581
This paper deals with modeling the most commonly used passive and active differentials, conceived for Four Wheel Drive (4WD) systems. The vehicle dynamics of a 4WD equipped with the modeled differentials is investigated. The models presented are both based on a functional approach and, according to a more detailed analysis, based on the physical performance of the components constituting a differential.
Technical Paper

Customer Oriented Vehicle Dynamics Assessment for Autonomous Driving in Highway

2019-04-02
2019-01-1020
Autonomous Driving is one of the main subjects of academic research and one important trend in the automotive industry. With the advent of self-driving vehicles, the interest around trajectory planning raises, in particular when a customer-oriented analysis is performed, since more and more the carmakers will have to pay attention to the handling comfort. With that in mind, an experimental approach is proposed to assess the main characteristics of human driving and gain knowledge to enhance quality of autonomous vehicles. Focusing on overtaking maneuvers in a highway environment, four comfort indicators are proposed aiming to capture the key aspects of the chosen paths of a heterogeneous cohort. The analysis of the distribution of these indicators (peak to peak lateral acceleration, RMS lateral acceleration, Smoothness and Jerk) allowed the definition of a human drive profile.
Technical Paper

Braking System Components Modelling

2003-10-19
2003-01-3335
The paper deals with a method implemented to study braking systems design, modelling components' characteristics through commercial software. It summarizes the potential improvement possible by using modelling techniques in chassis systems design. The first part consisted in producing a passive braking system model. A first validation was carried out on a test bench by using components of different braking systems. Particular attention was devoted to booster modelization both in semi-stationary and dynamic conditions. The second part was callipers, roll-back and thermal phenomena modelization. Finally, it were modelled Anti-lock Braking System (ABS) and Vehicle Dynamics Control (VDC) Hydraulic Units and their integration with control strategies and with vehicle dynamics model.
Technical Paper

Base Model Simulator (BMS) - A Vehicle Dynamics Model to Evaluate Chassis Control Systems Performance

2005-04-11
2005-01-0401
Chassis Control Systems development methodology is nowadays strongly based on analyzing performance by using PC vehicle dynamics simulation. Generally, the overall design, test bench and road validation process is continuously accompanied by simulation. The Base Model Simulator was developed by the Vehicle Dynamics Group at the Department of Mechanics of Politecnico di Torino both to satisfy this requirement and for educational purposes. It considers a complete vehicle dynamics mathematical model, including driver, powertrain, driveline, vehicle body, suspensions, steering system, brakes, tires. The Base Model Simulator takes in account the suspensions system elastokinematics, including, for example, automatic computation of camber variation during the vehicle roll motions. Tire model considered are either Pacejka's models or experimental data.
Technical Paper

An Objective Evaluation of the Comfort During the Gear Change Process

2007-04-16
2007-01-1584
This paper presents the methodology adopted by Politecnico di Torino Vehicle Dynamics Research Team to obtain objective indices for the evaluation of the comfort during the gear change process. Some test drivers and different passengers traveled on a test vehicle and assigned marks on the basis of their subjective feeling of comfort during the gearshifts. The comparison between the most significant subjective evaluations and the experimental values obtained by the instruments located on the vehicle is presented. As a consequence, some indices (based on physical parameters) to evaluate the efficiency and the comfort of the gearshift process are obtained. They are in good agreement with the subjective evaluations of the drivers and the passengers. The second part of the paper presents a driveline and vehicle model which was conceived to reproduce the phenomena experimented on the vehicle. The experimental validation of the model is presented.
Technical Paper

A Methodology to Investigate the Dynamic Characteristics of ESP and EHB Hydraulic Units

2006-04-03
2006-01-1281
The paper deals with the Hardware-In-the-Loop based methodology which was adopted to evaluate the dynamic characteristics of Electronic Stability Program (ESP) and Electro-Hydraulic Brake (EHB) components. Firstly, it permits the identification of the time delays due to the hardware of the actuation system. Secondly, the link between the hardware of the hydraulic unit and a vehicle model running in real time permits the objective evaluation of the performance induced by the single components of different hydraulic units in terms of vehicle dynamics. The paper suggests the main parameters and tests which can help the car manufacturer in evaluating ESP hydraulic units, without expensive road tests.
Technical Paper

A Deep Learning based Virtual Sensor for Vehicle Sideslip Angle Estimation: Experimental Results

2018-04-03
2018-01-1089
Modern vehicles have several active systems on board such as the Electronic Stability Control. Many of these systems require knowledge of vehicle states such as sideslip angle and yaw rate for feedback control. Sideslip angle cannot be measured with the standard sensors present in a vehicle, but it can be measured by very expensive and large optical sensors. As a result, state observers have been used to estimate sideslip angle of vehicles. The current state of the art does not present an algorithm which can robustly estimate the sideslip angle for vehicles with all-wheel drive. A deep learning network based sideslip angle observer is presented in this article for robust estimation of vehicle sideslip angle. The observer takes in the inputs from all the on board sensors present in a vehicle and it gives out an estimate of the sideslip angle. The observer is tested extensively using data which are obtained from proving grounds in high tire-road friction coefficient conditions.
X