Warren Manning

Coordination of active steering, driveline, and braking for integrated vehicle dynamics control:

Abstract An integrated vehicle dynamics control system which aims to improve vehicle handling and stability by coordinating active front steering (AFS) and dynamic stability control (DSC) subsystems is developed in this paper. The DSC subsystem includes driveline-based, brake-based, and driveline plus brake-based DSC subsystems. The influence of varying forward speed and lateral acceleration on the lateral vehicle dynamics is investigated first. The AFS controller, which is used to improve vehicle steerability in the low to mid-range lateral acceleration, and the DSC controller, which manages to maintain vehicle stability during extreme driving situations, are then designed by using the sliding mode control (SMC) technique and phase plane method respectively. Based on the two independently developed controllers, a rule-based integration scheme is proposed to optimize the overall vehicle performance by minimizing interactions between the two subsystems and extending functionalities of individual subsystems. Computer simulation results confirm the effectiveness of the proposed control system and the overall improvements in vehicle handling and stability.

A review of yaw rate and sideslip controllers for passenger vehicles

The development of chassis control schemes has been a major area of study for automotive control engineers over the past 30 years. The volume of published literature is large, exceeding 1000 papers. Of this literature, there are 250 examining yaw and sideslip control. Here is a comprehensive review of this field of study to identify the current state of the art and research in yaw rate and sideslip control. The survey shows that there is still a significant research effort needed to address the subjective performance of handling systems, and more research is needed to develop schemes that integrate systems to achieve high-level performance objectives.

Use of an extended Kalman filter as a robust tyre force estimator

Control systems designed to optimize vehicle performance, such as antilock braking systems or traction control systems, depend upon a knowledge of the amount of available grip at the tyre–road contact point. There have been both qualitative and quantitative approaches to identify the road surface coefficient of friction, μ. This work proposes a method of estimating the longitudinal and lateral grips for use within a control system. The estimation method is explained and the vehicle model equations used are stated. The estimator is then tested using logged data from a test vehicle, and the force estimates are validated against results from strain-gauged wheel rims. Finally, the direction of future work is described.

Advanced driver assistance systems: Objective and subjective performance evaluation

This paper details the design of two advanced driver assistance systems from concept to fully integrated solutions that are installed and tested on a driving simulator. The systems were tuned and validated using offline simulations before they were installed on the Leeds driving simulator. The simulator is equipped with a large amplitude motion base that is able to generate realistic sustained accelerations. The work forms a part of the effects of automated systems on safety project that is funded by the EPSRC. This simulator study acts a pilot study for the project. Drivers were subjected to a range of scenarios, some of which required evasive action. The two systems, adaptive cruise control and a lane keeping system, were tested in isolation, while the performance of each system and the driver were monitored. The driver was then asked to complete questionnaires on each controller. The nature of this pilot study meant that the sample size was small, but the results still demonstrate some interesting trends. The results of assisted and non-assisted driving were compared and the merits of each system were discussed.

Reduced-order robust multivariable control of a double-beam cantilever structure

Vibration control of a two-dimensional smart structure is presented. The least squares identification technique and a novel pole identification method are used to obtain accurate plant models. Comparable accuracy is achieved with a significantly lower model order using the latter method. A multivariable multi—input multi—output (MIMO) generalized minimum variance control scheme is used to address robustness issues of plant mismodeling, unmodeled modes/dynamics and control signal saturation. The controllers are tested for robustness to spillover problems. Results are further supported with the use of sensitivity response functions.

Automotive Collision Mitigation Through Vehicle Dynamic Control

The ever important development of automotive crash mitigation systems has, over recent years, lead to the development of Advance Driver Assistance (ADA) systems. These systems use a variety of approaches to help avoid vehicle collision from occurring. However, these systems are still far from being able to prevent all collisions from occurring in the current environment. This work aims to use vehicle dynamic control systems to optimize the vehicle’s dynamic characteristics for an impending collision. This will utilize the detection systems developed for these ADA systems, to detect when an imminent collision has become unavoidable. To perform such studies, it is important to have a vehicle dynamic simulation that can also include the vehicle crash structural dynamics. These factors are key to analysing the point-of-impact and post-impact vehicle dynamics and the effects on the outcome of the impact. This paper outlines the initial development of a multibody vehicle dynamic crash analysis model. This enables the analysis of a generic vehicle dynamic model, together with a simple crash model, so that the effects of a variety of simple dynamic control approaches can be analysed. This will give a valuable insight into the effects of vehicle dynamic control on the collision severity. Initial results show that this simple and fast method of simulating both the vehicle dynamics and crash dynamics in a simple multibody model can be an effective and accurate tool for generic vehicle analysis. Results also show that even simple vehicle dynamic controls during the pre-impact, impact and post-impact stages of the collision can have a significant effect on the impact severity.© 2007 ASME

Linear modeling and control of a cantilever beam with bonded piezoelectrics using finite elements software

The ability to model, investigate and control the behavior of dynamic systems in a simulation environment is highly desirable due to time and cost benefits. A new technique has been developed allowing finite element models to be integrated with Simulink for dynamic simulation and control. The technique is presented by the modeling of a fixed-free cantilever beam with bonded piezoelectric patches. A description of the modeling technique is presented detailing the process of model creation, including input and output variable determination, and exportation to Simulink as a state-space model. A comparison of simulated and experimental open-loop behavior is provided. Furthermore the free and forced system behavior both observed, and simulated with velocity feedback controllers (VFB) is presented. Conclusions are drawn regarding the capabilities and restrictions of the developed technique in comparison to modeling using a system identification technique. The authors views on the techniques application to non-linear system modeling and potential for optimizing sensor and actuator locations are presented.