Stable headway prediction of vehicle platoon based on the 5-degree-of-freedom vehicle model

2018 ◽  
Vol 233 (6) ◽  
pp. 1570-1585 ◽  
Author(s):  
Shuming Shi ◽  
Ling Li ◽  
Yu Mu ◽  
Guanghui Chen
Keyword(s):  
Ad Hoc Network ◽  
Ad Hoc ◽  
Rotational Velocity ◽  
Autonomous Vehicle ◽  
Degree Of Freedom ◽  
Vehicle Stability ◽  
Vehicle Model ◽  
Vehicle System ◽  
Vehicle Platoon ◽  
The Stability

Vehicular ad hoc network and cooperative adaptive cruise control system make vehicle platooning with small headway feasible. In the study of the autonomous vehicle platoon system under the vehicular ad hoc network condition, the linear vehicle model is usually used to analyze the minimum space-gap, safety space-gap, and so on. However, the stability of nonlinear vehicle system shows that there are limitations when using the linearized vehicle model to analyze vehicle stability. The linear model cannot reflect the influence of the system nonlinear coupling on the vehicle stability. Therefore, in this paper, we use the validated 5-degree-of-freedom (longitudinal velocity, lateral velocity, yaw rate, front wheel rotational velocity, and rear wheel rotational velocity) nonlinear model to analyze the stable intra-platoon spacing of the autonomous vehicle platoon system under the condition of VANET. In order to study the safety intra-platoon spacing of vehicle platoon running in the complex path, a following controller is designed for vehicle platoon running in the corners. The controller adopts the method of vertical and horizontal decentralized control. The longitudinal control is to realize the expected space-gap of vehicles in vehicle platoon, and the lateral control is to achieve the position and orientation following of the preceding vehicle. Based on the stability verification of the following controller, the following control characteristics of vehicle system are analyzed, and the stable headway required for vehicles in vehicle platoon running in the complex path is predicted by the method of simulation experiment.

scholarly journals The Topology Stability of Vehicular Ad Hoc Network

2012 ◽  
Vol 6-7 ◽  
pp. 1004-1009 ◽  
Author(s):  
Tong Zhou He ◽  
Yan Jun Shen
Keyword(s):  
Routing Protocols ◽  
Ad Hoc Network ◽  
Ad Hoc ◽  
Simulation Experiment ◽  
Vehicular Ad Hoc Network ◽  
Intersection Angle ◽  
Movement Velocity ◽  
The Stability ◽  
Vehicle Movement ◽  
Valid Time

The goal of this paper is to look for relatively stable area in the Vehicular Ad hoc Network (VANET), thereby helping for developing more stable routing protocols. We built a theoretical model to analysis the stability of the VANET topology, and provided the simulation experiment to verify the correctness of the theoretical analysis. Results show that the vehicle traveling in the same direction is easier to maintain the stability of the topology of a VANET, and the valid time of the path will decrease with the increase of the intersection angle in the direction of the vehicle movement, the vehicle movement velocity and the time. In addition, the simulation results also show that the bigger the initial distance among the vehicles is, the less stable the network topology is. The discovery of this phenomenon is important to develop zoned routing protocols.

Stability of Controlled Road Vehicles: A Preliminary Fundamental Study

2015 ◽  
Author(s):  
Fabio della Rossa ◽  
Massimiliano Gobbi ◽  
Giampiero Mastinu ◽  
Carlo Piccardi ◽  
Giorgio Previati
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Preliminary Investigation ◽  
Basin Of Attraction ◽  
Lateral Acceleration ◽  
Steering Wheel ◽  
Vehicle Speed ◽  
Vehicle Model ◽  
The Stability ◽  
Positive Effect

A comparison of the lateral stability behaviour between an autonomous vehicle, a vehicle with driver and a vehicle without driver (fixed steering wheel) is made by introducing a simple mathematical model of a vehicle running on even road. The mechanical model of the vehicle has two degrees of freedom and the related equations of motion contain the nonlinear tyre characteristics. The driver is described by a well-known model proposed in the literature. The autonomous vehicle has a virtual driver (robot) that behaves substantially like a human, but with its proper reaction time and gain. The road vehicle model has been validated. The study of vehicle stability has to be based on bifurcation analysis and a preliminary investigation is proposed here. The accurate computation of steady-state equilibria is crucial to study the stability of the three kinds of vehicles here compared. The stability of the bare vehicle without driver (fixed steering wheel) is studied in a rather complete way referring to a number of combinations of tyre characteristics. The (known) conclusion is that the understeering vehicle is stable at each lateral acceleration level and at each vehicle speed. The additional (partially unknown) conclusion is that the vehicle (model) with degradated tyres may exhibit a huge number of different bifurcations. The driver has many effects on the stability of the vehicle. One positive effect is to eliminate the many possible different equilibria of the bare vehicle and keep active one single equilibrium only. Another positive effect is to broaden the basin of attraction of stable equilibria (at least at relatively low speed). A negative effect is that, even for straight running, the driver seem introducing a subcritical Hopf bifurcation which limits the maximum forward speed of some understeering vehicles (that could run faster with fixed steering wheel). Both the mentioned positive and negative effects appear to be applicable to autonomous vehicles as well. Further studies could be useful to overcome the limitations on the stability of current autonomous vehicles that have been identified in the present research.

Fuzzy Logic Based Vehicle Stability Enhancement Through Combined Differential Braking and Active Front Steering

2005 ◽  
Author(s):  
J. Ahmadi ◽  
A. Ghaffari ◽  
R. Kazemi
Keyword(s):  
Fuzzy Logic ◽  
Steering System ◽  
Vehicle Stability ◽  
Fuzzy Logic Controllers ◽  
Vehicle Model ◽  
Active Front Steering ◽  
Highly Nonlinear ◽  
Road Condition ◽  
The Stability ◽  
Stability Enhancement

This paper examines the usefulness of a combined differential braking and active front steering system on the stability enhancement of a vehicle. The two manipulated inputs for steering intervention are the added front steer angle and the brake torque, where the later is applied at only one wheel at a time. In this study active front steering controller is designed independent of differential braking controller. Since the yaw and lateral motions are highly nonlinear, two fuzzy logic controllers are constructed to compensate the effects of road condition and parameter variation. Computer simulations using nonlinear seven degree of freedom vehicle model show the strong capability of the combined approach and its relative merit compared to the case that one subsystem is actuated.

A Study of the Wheel Geometry Effect on the Dynamic Behavior of Railroad Vehicles

2005 ◽  
Author(s):  
Ahmed A. Shabana ◽  
Mahmoud Tobaa ◽  
Khaled E. Zaazaa
Keyword(s):  
Critical Speed ◽  
Single Point ◽  
Vehicle Stability ◽  
Point Contacts ◽  
Vehicle Model ◽  
Geometric Properties ◽  
Railroad Vehicles ◽  
Wheel Profile ◽  
The Stability ◽  
Railroad Vehicle

The effect of the geometry of a wheel profile that allows only a single point of contact between the wheel and the rail is investigated in this study. The local geometric properties of this profile are compared with the local geometric properties of a profile that allows for two-point contacts in order to understand the basic differences between the two profiles. A simple model is first used to examine the effect of the profile geometry on the stability and nonlinear dynamics of a suspended wheel set. The results obtained in this paper show that the wheel profile can significantly alter the critical speed. Using surface parameters that define the wheel and rail geometry, the global representations of the positions of the points on the wheel and rail surfaces are obtained and used to define the conditions of the contact between the wheel and the rail. Numerical results are presented for a full railroad vehicle model and the effect of the wheel profile on the vehicle stability is investigated. A comparison between the results obtained using the two wheel profiles in the case of wheel climb scenarios is presented.

Realization of Route Reconstructing Scheme for Mobile Ad hoc Network

2011 ◽  
pp. 62-79 ◽  
Author(s):  
Qin Danyang ◽  
Ma Lin ◽  
Sha Xuejun ◽  
Xu Yubin
Keyword(s):  
Ad Hoc Network ◽  
Ad Hoc ◽  
Mobile Ad Hoc Network ◽  
Heavy Traffic ◽  
Route Maintenance ◽  
End To End Delay ◽  
Communication Links ◽  
Mobile Ad Hoc ◽  
End To End ◽  
The Stability

Mobile Ad Hoc Network (MANET) is a centerless packet radio network without fixed infrastructure. In recent years tremendous attentions have been received because of capabilities of self-configuration and self-maintenance. However, attenuation and interference caused by node mobility and wireless channels sharing weaken the stability of communication links especially in ubiquitous MANET. A mathematical exploring model for next-hop node has been established. The negative impact of wireless routes discontinuity on pervasive communication is alleviated by a novel route reconstructed scheme proposed in this paper based on restricting the route requirement zone into a pie slice region on intermediate nodes according the solution of the exploring equation. The scheme is an effective approach to increase survivability and reduce average end-to-end delay during route maintenance as well as allowing continuous packet forwarding for fault resilience so as to support mobile multimedia communication. The ns-2 based simulation results show remarkable packets successful delivery rate and end-to-end delay improvements of source-initiated routing protocol with route reconstructing scheme, and especially in the case of high dynamic environments with heavy traffic loads, more robust and scalable performance will be obtained.

Design method for a powertrain mounting system to decrease the vehicle key on/off vibrations

2017 ◽  
Vol 232 (9) ◽  
pp. 1221-1236 ◽  
Author(s):  
Dao-Yong Wang ◽  
Xue-Zhi Zhao ◽  
Wen-Bin Shangguan
Keyword(s):  
High Frequency ◽  
Design Method ◽  
Degree Of Freedom ◽  
Dynamic Force ◽  
Response Evaluation ◽  
Vehicle Model ◽  
Vehicle System ◽  
High Frequency Vibrations ◽  
Excitation Force ◽  
Engine Start

Five dynamic response evaluation indices from the viewpoint of the powertrain mount system and the vehicle system during the vehicle key on/off periods (i.e. the engine start and stop) are proposed. By analysis using different methods to minimize the powertrain vibration, it was found that an increase in the mount system damping can decrease the vehicle key on and key off vibration. For this reason, in this paper a semi-active hydraulic damping strut is designed and made which can provide high damping for a mount system when the vehicle key on/off but switches to lower damping to isolate high-frequency vibrations under normal conditions. The calculated longitudinal acceleration of the powertrain, the jerk of the powertrain, the dynamic force of the mount and the vibration dose value for a vehicle with the semi-active hydraulic damping strut and without the semi-active hydraulic damping strut are compared on the basis of the excitation force identified for the powertrain using a 13-degree-of-freedom vehicle model. Experiments were carried out, and the results show that the use of the semi-active hydraulic damping strut can decrease the engine start and stop vibrations to a large extent. Finally, the experimental results are compared with the calculated values from the 13-degree-of-freedom vehicle model.

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