Topic
Vehicle dynamics
About: Vehicle dynamics is a research topic. Over the lifetime, 12909 publications have been published within this topic receiving 204091 citations.
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01 Jun 2018TL;DR: The dynamic modeling and control of high-speed automated vehicles for lane change maneuver is presented, using a nonlinear single-track vehicle dynamics model and a multisegment lane change process model to ensure longitudinal safety of this maneuver.
Abstract: Lane change maneuver of high-speed automated vehicles is complicated, since it involves highly nonlinear vehicle dynamics, which is critical for the driving safety and handling stability. Addressing this challenge, we present the dynamic modeling and control of high-speed automated vehicles for lane change maneuver. A nonlinear single-track vehicle dynamics model and a multisegment lane change process model are employed. Variable time steps are utilized for the vehicle model discretization to ensure a long enough prediction horizon, while maintaining model fidelity and computational feasibility. Accordingly, the control of lane change maneuver is addressed in two successive stages. First, by considering the lane change maneuver as primarily a longitudinal control problem, velocity profiles are determined to ensure the longitudinal safety of this maneuver. Then, the associated lateral control is generated with a model-predictive controller, taking the handling stability envelope, coupled tire forces, and environmental constraints into account. Simulations demonstrate the real-time ability and stable-handling capability of the proposed approach.
73 citations
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TL;DR: An improved disturbance observer based ISMC strategy is designed to cope with the unknown mismatched disturbances, and the composite nonlinear feedback technique is employed to design the nominal part of the controller to restrain overshoots and remove steady-state errors considering the tire force saturations.
Abstract: Differential drive assistance steering (DDAS) is an emerging assisted steering mechanism in in-wheel-motor driven (IWMD) electric vehicles, yielded by the differential moment of the front tires in the steering system. DDAS can steer the front wheels when there is no steering power from the steering motor, and thus can be used as a redundant steering mechanism. To realize the yaw control when the active front steering entirely breaks down and guarantee the transient control performance therein, this paper proposes an integral sliding mode control (ISMC) approach for IWMD electric vehicles steered by DDAS. Two contributions are made in this paper: 1) An improved disturbance observer based ISMC strategy is designed to cope with the unknown mismatched disturbances, and the composite nonlinear feedback technique is employed to design the nominal part of the controller to restrain overshoots and remove steady-state errors considering the tire force saturations; 2) An adaptive super-twisting control approach is proposed to deal with the disturbances with unknown boundaries using a continuous controller while eliminating the chattering effect. The system stability and robustness are proved via Lyapunov approach. CarSim-Simulink simulation has verified the effectiveness of the proposed control approach in the case of the steering fault.
73 citations
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26 Jun 1991
TL;DR: The new goal of dynamic systems integration is to carry out concurrent multidisciplinary design of the highly interactive systems to maximize overall aircraft performance in its broadest terms.
Abstract: TraditionaLly the systems integration process in aerospace controls is to make individually desig subsystems work together, that is, to ensure functional compatibility and minimize adverse interactions. With large hypersonic vehicles the aerodynamic, propulsion, structural, and controls features are intrinsically highly interactive dynamically over a wide range of frequencies. Consequently, systems integration activities must be enormously expanded in scope and degree to assure a successful result. In essence the new goal of dynamic systems integration is to carry out concurrent multidisciplinary design of the highly interactive systems to maximize overall aircraft performance in its broadest terms. Cooperative consolidation and interaction of functions and subsystems to achieve performance levels and design synergism greater than would be possible with independent, individual subsystem designs are the natural consequences desired.
73 citations
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TL;DR: In this paper, the authors used a nine-degrees-of-freedom (DOF) vehicle model and simulations of a fishhook manoeuvre to assess the handling performance of a vehicle when it is fitted with either a conventional independent suspension or a hydraulically interconnected suspension.
Abstract: This paper extends recent research on vehicles with hydraulically interconnected suspension (HIS) systems. Such suspension schemes have received considerable attention in the research community over the last few years. This is due, in part, to their reported ability to provide stiffness and damping rates dependent on the suspension mode of operation (i.e. the bounce, roll, pitch or articulation of the unsprung masses relative to the sprung mass), rather than relying on the stiffness and damping characteristics of the single wheel stations. The paper uses a nine-degrees-of-freedom (DOF) vehicle model and simulations of a fishhook manoeuvre to assess the handling performance of a vehicle when it is fitted with: (a) a conventional independent suspension, and (b) an HIS. In the case of the latter, the fluid subsystem is modelled using a nonlinear finite-element approach, resulting in a set of coupled, first-order nonlinear differential equations, which describe the dynamics of the integrated mechanical-hydraulic vehicle system. The simulation results indicate that, in general, the HIS-equipped vehicle possesses superior handling, as measured by the sprung mass roll angle, roll rate, roll acceleration, lateral acceleration and the vehicle's Rollover Critical Factor. The potential effects of the suspension set-up on ride performance are also considered by studying the transient response when one side of the vehicle traverses a half-sine bump. The obtained results are then discussed, and it is shown that they are consistent with previous findings, both by the authors and other researchers. The presented work outlines an alternative approach for studying the dynamics of HIS-equipped vehicles, particularly suited to analyses in the time domain.
73 citations
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TL;DR: A new adaptive vehicle suspension control method is presented that adjusts the controller parametrization to the current driving state and thereby enables to significantly enhance ride comfort while the dynamic wheel load and the suspension deflection remain within safety critical bounds.
Abstract: A new adaptive vehicle suspension control method is presented that adjusts the controller parametrization to the current driving state and thereby enables to significantly enhance ride comfort while the dynamic wheel load and the suspension deflection remain within safety critical bounds. To this end, the adaptive controller structure dynamically interpolates between differently tuned linear quadratic regulators governed by the dynamic wheel load and the suspension deflection. The stability of the adaptive controller structure is analyzed by means of a common Lyapunov function approach taking into account the nonlinear damper characteristic of the suspension system. In order to provide a realistic framework for the controller design and the performance analysis, a quarter-car test rig based on an all-terrain vehicle suspension that has been equipped with an electrical linear motor to realize an active suspension system, is employed as testbed for the study. On this test rig, the significant performance of the adaptive control concept is successfully validated in a comparison to benchmark suspension controllers.
73 citations