A method for automatic generation of linearised equations of motion for vehicle stability analysis has been presented. This method proposes a significant change from conventional methods for generating linearised equations of motion, allowing for easy inclusion of nonholonomic constraints. The proposed change performs the elimination of the algebraic constraint equations after linearisation and reduction to first-order form. The method presents equations of motion well suited for vehicle stability analysis. The method was implemented in GNU Octave, allowing for visual and numerical analysis of system models. The efficacy of the developed method and implementation were demonstrated by application to various benchmark problems including the rolling coin, truck and trailer, bicycle, and a conventional four-wheeled vehicle with independent suspensions. The stability analysis results of these models were shown to correlate well with those presented in the literature. It can be inferred from this correlation that the method can be used to provide detailed insight into the response of vehicle systems of various size and complexity. Finally, a novel narrow three-wheeled vehicle with zero roll-stiffness was presented. The stability of this system was evaluated using the proposed implementation, indicating an unstable nominal configuration. This configuration exhibited three unstable motions attributed to undesirable tilting, steering, and yaw rotations. By applying a purpose-developed GSA to a model with fixed forward speed, a more inherently stable vehicle configuration was found. The genetically derived configuration exhibited trail on the steering wheels, which has been shown to contribute to the stability of bicycles and other NTVs. Conducting a stability analysis over the expected operating speed range of the vehicle indicated a region of selfstability located between a disappearing low-speed tilt instability and a high-speed oversteer yaw instability. As a result, the passive stability of the proposed vehicle was markedly improved without the addition of active stability controls. The proposed method and implementation has been shown to be a useful tool in stability analysis and design of systems with non-holonomic constraints. They are well suited for use in automatic generation of equations of motion with application in vehicle dynamics. Future use of this method includes analysis of novel and complex vehicle architectures as well as stability control development.
Automatic generation of the non-holonomic equations of motion for vehicle stability analysis
Vehicle System Dynamics ; 48 , 9 ; 1043-1063
2010
21 Seiten, 9 Bilder, 6 Tabellen, 13 Quellen
Article (Journal)
English
Automatic generation of the non-holonomic equations of motion for vehicle stability analysis
Taylor & Francis Verlag | 2010
|Automatic generation of the non-holonomic equations of motion for vehicle stability analysis
Automotive engineering | 2010
|Automatic generation of the non-holonomic equations of motion for vehicle stability analysis
Online Contents | 2010
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