Vehicle Design Highlights

ARCHIVES

Title: Fault diagnostics in power electronics-based brake-by-wire systems

Author(s): M A Masrur, H-J Wu, C Mi, Z-H Chen, Y L Murphey

Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering

Volume: 222 Page: 1-11. Jan 2008

DOI: 10.1243/09544070JAUTO385

Publisher: Professional Engineering Publishing

Abstract: A d.c.-motor-based brake-by-wire system is studied for the purpose of fault diagnostics of the power electronic switches. The voltage and current generated in the switching circuit under normal and six faulted conditions are observed. A hierarchical fuzzy diagnostic system has been developed to detect certain types of fault condition in any specific solid state power switch at the moment immediately after the occurrence of the fault. The hierarchical fuzzy diagnostic system has been tested and validated using data from both a simulation and a laboratory set-up with a 1 / 3 hp d.c. motor and a d.c.-to-d.c. converter. The system performance has been compared with two different fuzzy diagnostic systems and the results are presented. The hierarchical fuzzy diagnostic system trained on the simulated model has the capability of detecting certain types of fault condition occurring in a brake-by-wire actuator system set-up in a laboratory in less than 0.0009 s and pinpointing the specific types of fault within less than 0.013 s.

Title: Optimal brake torque distribution for a four-wheeldrive hybrid electric vehicle stability enhancement

Author(s): D-H Kim, J-M Kim, S-H Hwang, H-S Kim

Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering

Volume: 221, Number 11 / November 2007 Pages 1357-1366

DOI: 10.1243/09544070JAUTO352

Publisher: Professional Engineering Publishing

Abstract:
Vehicle stability control logic for a four-wheel-drive hybrid electric vehicle is proposed using the regenerative braking of the rear motor and an electrohydraulic brake (EHB). To obtain the optimal brake torque distribution between the regenerative braking and the EHB torque, a genetic algorithm is used. The genetic algorithm calculates the optimal regenerative braking torque and the optimal EHB torque for the given inputs of the desired yaw moment and road friction coefficient. Based on the optimal brake torque distribution, the vehicle stability control logic proposed generates the desired direct yaw moment to compensate the errors of the side-slip angle and yaw rate by a fuzzy control algorithm corresponding to the driver's steering angle and vehicle velocity. Performance of the vehicle stability control logic is evaluated by comparison of the fixed regenerative braking and the optimal regenerative braking for a single lane change manoeuvre. It is found from the simulation results that the optimal regenerative braking is able to provide the increased recuperation energy compared with the fixed regenerative braking while satisfying the vehicle stability.

Title: A study on an anti-lock braking system controller and rear-wheel controller to enhance vehicle lateral stability

Author(s): Jeonghoon Song, Heungseob Kim, Kwangsuck Boo

Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering

Volume: 221, Number 7 / July 2007 Pages 777-787

DOI: 10.1243/09544070JAUTO225

Publisher: Professional Engineering Publishing

Abstract:
This paper presents a mathematical vehicle model that is designed to analyse and improve the dynamic performance of a vehicle. A wheel slip controller for anti-lock braking system (ABS) brakes is formulated using a sliding mode controller and a proportional-integral-derivative (PID) controller for rear wheel steering is also designed to enhance the stability, steerability, and driveability of the vehicle during transient manoeuvres. The braking and steering performances of controllers are evaluated for various driving conditions, such as straight and J-turn manoeuvres. The simulation results show that the proposed full car model is sufficient to predict vehicle responses accurately. The developed ABS reduces the stopping distance and increases the longitudinal and lateral stability of both two-and four-wheel steering vehicles. The results also demonstrate that the use of a rear wheel controller as a yaw motion controller can increase its lateral stability and reduce the slip angle at high speeds.

Title: A study of commercial vehicle brake judder transmission using multi-body dynamic analysis


Author(s): K Hussain, S H Yang, A Day

Source: Proceedings of the I MECH E Part K Journal of Multi-Body Dynamics

Volume: 221, Number 2 / 2007 Pages 311-318

DOI: 10.1243/1464419JMBD23

Publisher: Professional Engineering Publishing

Abstract:
Braking-induced forced vibration, known as brake judder in road vehicles, causes dissatisfaction to drivers and passengers and also damage and possible early failure in components and systems. In this paper, the transmission of judder vibration from the point of generation (the brake friction pair) through the vehicle structure to the driver is investigated for the particular case of a heavy commercial vehicle. The investigation uses a computer simulation multi-body dynamic model based on the automatic dynamic analysis of mechanical systems software to identify any characteristics of the vehicle suspension design that might influence the vibration transmission from the wheel to the driver.

The model uses a simplified rigid chassis and cab to lump the chassis parameters, so that the investigation can focus on the front axle/suspension design, which is a beam axle leaf spring arrangement, and the rear axle/suspension assembly, which is a tandem axle bogie design. Results from the modelling indicate that brake judder vibration is transmitted to the chassis of the vehicle through a leaf spring ‘wind-up’ mode and a ‘walking’ mode associated with the rear tandem axle. Of particular interest is the longitudinal vibration transmitted through the chassis, since this creates a direct vibration transmission path to the cab and driver. The simulation results were compared with the previously published experimental work on the same design of commercial vehicle, and agreement between the predicted and the measured vibration characteristics and frequencies was found.

It is concluded that the rear suspension design parameters could affect the transmission of brake judder vibration to the cab and driver and that a tandem rear axle offers some design opportunity to control the transmission of brake judder vibrations from the wheel to the cab and driver. Given that brake judder has so far defied all attempts to eliminate completely from vehicle brake systems, this is potentially an important opportunity.

Title: Integrated control of suspension and front steering to enhance vehicle handling


Author(s): C. March, T. Shim

Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering

Volume: 221, Number 4 / 2007 Pages 377-391

DOI: 10.1243/09544070JAUTO152

Publisher: Professional Engineering Publishing

Abstract: Integration of vehicle chassis control system has gained increasing attention since it can improve the vehicle safety and performance through effective coordination of individual control systems. This paper presents the development of an integrated control system of active front steering and normal force control using fuzzy reasoning to enhance the vehicle-handling performance. Individual control systems were first developed, and then their performances were compared with that of the integrated system. The simulation results indicate that the integrated chassis control scheme utilizing the steering and suspension controllers has proven to be more effective in attaining the desired performance that would not be attained individually.

Title: Standard multi-body system software in the vehicle development process

Author(s): E. Fischer

Source: Proceedings of the I MECH E Part K Journal of Multi-Body Dynamics

Volume: 221, Number 1 / 2007 Pages 13-20

DOI: 10.1243/1464419JMBD59

Publisher: Professional Engineering Publishing

Abstract: In the developmental processes of a complex product, such as a passenger car, simulation software tools are used today to such an extent that the notion of a ‘virtual development process’ is justified, paralleling the hardware-based development process. In conjunction with several other software tools, a multi-body software system (MBS) can be an integral part of the virtual process, covering the area of suspension analysis and vehicle dynamics, provided it is tailored to the specific needs of the product, the software users, and the industrial organization. This article describes these needs by showing the context in which MBS is used, its interface with other tools, and the expectations of the users and concludes with an assessment of the current state.

Title: Structural analysis of steering wheel grip comfort by the semantic differential method

Author(s): K Nishina, M Nagata, N Ishii

Source: Proceedings of the I MECH E Part I Journal of Systems and Control Engineering     
Volume: 220 Page: 675-681. Nov 2006

DOI: 10.1243/09596518JSCE145

Publisher: Professional Engineering Publishing

Abstract: Kansei quality varies with the individual. Therefore, when building a structural model of Kansei quality, it is very important to identify some essential structures by analysing individual differences. In this paper, the semantic differential method is used to improve steering wheel grip comfort. Assuming a hierarchical structural model of the steering wheel grip comfort, the individual differences are analysed using principal component analysis, and then some hierarchical structural models are built using graphical modelling. As a result, two remarkably different structures are built. Some guidelines for developing steering wheel production can be shown by comparing the different structures.