Convoy Of Vehicles Research Articles

Using the lead vehicle as preview sensor in convoy vehicle active suspension control

Both ride quality and roadholding of actively suspended vehicles can be improved by sensing the road ahead of the vehicle and using this information in a preview controller. Previous applications have used look-ahead sensors mounted on the front bumper to measure terrain beneath. Such sensors are vulnerable, potentially confused by water, snow, or other soft obstacles and offer a fixed preview time. For convoy vehicle applications, this paper proposes using the overall response of the preceding vehicle(s) to generate preview controller information for follower vehicles. A robust observer is used to estimate the states of a quarter-car vehicle model, from which road profile is estimated and passed on to the follower vehicle(s) to generate a preview function. The preview-active suspension, implemented in discrete time using a shift register approach to improve simulation time, reduces sprung mass acceleration and dynamic tyre deflection peaks by more than 50% and 40%, respectively. Terrain can change from one vehicle to the next if a loose obstacle is dislodged, or if the vehicle paths are sufficiently different so that one vehicle misses a discrete road event. The resulting spurious preview information can give suspension performance worse than that of a passive or conventional active system. In this paper, each vehicle can effectively estimate the road profile based on its own state trajectory. By comparing its own road estimate with the preview information, preview errors can be detected and suspension control quickly switched from preview to conventional active control to preserve performance improvements compared to passive suspensions.

Trust-based coalition formation in multi-agent systems

In this paper, we provide a framework to study trust-based coalition formation in multi-agent systems using cooperative game theory as the underlying mathematical framework. We describe how to study trust dynamics between agents as a result of their trust synergy and trust liability in cooperative coalitions. We also rigorously justify the behaviors of agents for different classes of games and discuss how to exploit the formal properties of these games for cooperative control in an unmanned military vehicle convoy.

Implementation of robot routing approaches for convoy merging manoeuvres

Autonomous and cooperative guidance strategies for a convoy of electric vehicles in an urban context are challenging research topics in robotics and intelligent transportation systems. The vehicles that form the convoy eventually will have to leave it to perform a mission and return to the convoy formation once the mission has been accomplished. Nevertheless, the merging manoeuvres amongst the convoy and the units returning to it (pursuing units) is a complex task that involves the determination of the best merging point and the route across the city to reach it. This paper tackles this routing problem of a robot located in a map that is trying to join a convoy of robots in constant movement along a peripheral trajectory. We have developed two search strategies able to determine the optimal merging point and the best route to reach it: on one hand we describe a basic solution able to solve the problem when the time spent by the robot traveling along every street of the map is considered to be known and constant. On the other hand, we extended this basic approach to provide a new search strategy that considers uncertainty in traveling times. This increases considerably the complexity of the problem and makes necessary the inclusion of a risk factor that must be considered when determining the best route and the merging point for the manoeuvre. We also put our search strategies into practice in both, simulated and real scenarios. On one hand we have simulated the behavior of a convoy leader and a transport unit which is trying to join in the convoy, using Player&Stage. On the other hand we have used real P3-DX robot units as prototypes of electrical vehicles in a transport scenario.

Convoy Movement: Consideration of Turning Geometrics for Selected Vehicle Shapes

This research is aimed at facilitating the understanding of the restrictions of convoy movement with object shapes as they might apply to ground vehicles maneuvering in a theater-of-operations. Such a theater would include civilian or military disaster evacuation/relief and military security or logistics operations. The goal of the overarching study was first to identify routes for maximal throughput rate that will facilitate the maneuver of a convoy unit omnidirectionally (radially) to different localities at different elapsed times. The focus of this study was to characterize several models for physical boundary conditions. Having done so, they would be used to evaluate the passability of convoy vehicles through streets in an urban environment under different conditions of road geometry, especially at an intersection. Special cases are also evaluated to study the capability of the general models. Models for radius and length of curvature are also developed for different traffic geometrics such as intersections, curvature, and a circular island in an intersection. In all modeling approaches, detailed descriptions of the derivations are illustrated with numerical examples and figures. These road geometrics will help estimate the reduction of traffic speed for deployment of ground vehicles.

Method for the rapid evaluation of vehicle mobility on unpaved terrain

In cases where the mobilization of vehicle convoys in off-road conditions are considered, the mechanism of soil-vehicle interaction emerges as the key parameter controlling the travel time along the chosen route. Therefore, this paper proposes a new simplistic method that would allow the rapid evaluation of vehicle mobility in off-road conditions based on soil topography and vehicle characteristics. This method considers the limit equilibrium of soil under the loading conditions imposed by an accelerating vehicle and by natural terrain geometry. The influence of surface topography on soil’s stress state is considered by modifying the dynamic fluidization theory. In this paper it is proven that the underlying assumptions of the fluidization theory are very well suited to define the nature of stress rotations in sloping ground and the resulting geometry of bearing capacity failure surfaces. Additionally, in order to consider the inertial effects and the effects of shear transfer between the vehicle and the soil, a Coulomb-type mechanism is adopted.

Control and Reconguration of Train of Autonomous Electric Vehicles

This paper presents the concept of a convoy of autonomous electric vehicles which will be able to continue its mission in the presence of some actuator or sensor faults. The autonomous vehicle is called RobuCar which is constituted by four independently driven wheels and two independently adjustable steering angles. Firstly, the authors develop longitudinal and lateral controllers for the vehicles operating normally. The objective is to follow a reference trajectory and to maintain safe spacing between vehicles. Secondly, the authors develop some strategies based on fault detection and isolation results in order to reconfigure the convoy of vehicles in presence of faults. Three categories have been considered: sensor or actuator fault which has not altered the trajectory; fault that affects the velocity or disturbs the trajectory; faults that make impossible for the vehicle to continue its mission. Simulation results are given at the end to show the efficiency of the approach.

Recognition of convoys with array radar

Recognition of convoys of ground vehicles and estimation of the cross-range convoy length component during tracking by radar is discussed in this study. Radar with multi-channel array antenna is assumed. Such antenna offers the potential of spatial and space–time signal processing. For estimation of the cross-range length component generalised power estimators are used. In presence of ground clutter such techniques require an moving target indication (MTI) function including clutter suppression. In the case of moving radar space–time clutter suppression such as space–time adaptive processing (STAP) is required. It is shown that the direction of motion as well as the cross-range of the convoy can be retrieved from data obtained during tracking.

Communicating Vehicles in Convoy and Monocular Vision-based Localization

This article deals with mobile robotics in convoy. An autonomous vehicle has to follow the path of the vehicle ahead of it, but without having the vehicle ahead in its field of view. So, the task for the second vehicle is to follow the leader's path with a variable time delay. Moreover, relatively strong constraints are imposed in terms of speed of processing, precision of the localization and for communication. The vehicles of the convoy have to be localized in their environment without being detectable. So, the use of active sensors such as rangefinders, radars or laser sensors, is prohibited in the same way as GPS devices. The communication data rate between consecutive vehicles is low (10 kbits/s). The presented method allows in this context the replay of a path from input data based on 3D positions of some points supplied by the leader vehicle. This method combines data acquired by low cost sensors (odometer, gyroscope) and by a monocular camera through an Extended Kalman Filter (EKF). Simulation results as well as results of experiments conducted on real data demonstrate the effectiveness of the proposed approach.

“You Are Well Clear of Friendlies”: Diagnostic Error and Cooperative Work in an Iraq War Friendly Fire Incident

This paper considers diagnostic error in cooperative work as a contributing factor for a military `friendly fire' incident. It emphasises aspects of the moment-to-moment sequential organisation of interaction, and turn design, to explore the significance for the error of a loss of intersubjectivity and joint understanding. The paper uses as data the cockpit video recording from a US Air Force aircraft that fired on a British armoured vehicle convoy in March 2003, in the early days of the Iraq War. The analytic approach is grounded in concerns of ethnomethodology (EM) and conversation analysis (CA) for uncovering the language, practices and processes of reasoning by which people accomplish social actions, particularly for conducting cooperative work. The paper highlights the impact for the participants' perception, understanding and action of varying forms of participation, for example as speaker, addressed recipient, or as potential overhearing non-addressed recipient, and relative to participants' involvement in the task at hand, and to their possibilities for accessing relevant phenomena (i.e. the vehicles and their visible features). Diagnosis in cooperative work demands that participants act relative to one another's diverse perspectives and representations of the scene and its objects and events. Diagnosis requires participants to manage situations of ambiguity and uncertainty, and to resolve apparent conflicts of understanding and perceptual evidence. The paper examines the social character of diagnostic work by showing how processes of cooperation can be vulnerable and ultimately go wrong, particularly when multiple participants are physically distributed and interaction is mediated by communication technologies such as radio.

Application of the “Contact Convoy” Concept to Hybrid Electric Vehicles

This paper applies an intelligent intervehicle device (termed a ldquobridging damperrdquo) to a convoy of in-contact vehicles. The field of application is backup for future automated highways and operation of novel guided systems using vehicle-following control. The vehicle represented in computer simulations is a parallel hybrid electric automobile. Using the advanced vehicle simulator (ADVISOR) model, the vehicle representation is tuned to achieve matching of the overall force and power characteristics and the same performance over an urban driving cycle. The model for which a dedicated Matlab Toolbox was constructed is described. Simulation results compare the vehicle-following control on its own with a passive damper and a ldquoquasi-activerdquo damper that is controlled in collaboration with the vehicle's drivetrain. Using transient disturbances in the form of wind gusts and short gradients, power peaks and longitudinal ride quality (vibration dose value) are used to evaluate the performance.

Evaluation of semi-autonomous convoy driving

Autonomous mobility technologies may have applications to manned vehicle convoy operationsthey have the ability to enhance both system performance and operator capability. This effort examines the ...

Evaluation of semi‐autonomous convoy driving

AbstractAutonomous mobility technologies may have applications to manned vehicle convoy operations—they have the ability to enhance both system performance and operator capability. This effort examines the potential impact of introducing semi‐autonomous mobility [Convoy Active Safety Technologies (CAST)] into manned vehicles. Twelve civilians with experience driving military vehicles in convoy‐type operations participated in this experiment. For the experiment, they were tasked with following a lead vehicle while completing a concurrent security task (scanning the local environment for targets). The control of the manned vehicle was varied between CAST and manual control at several different speed levels. Several objective speed and accuracy variables along with subjective operator assessment variables were examined for each task. The results support the potential benefits of incorporating semi‐autonomous mobility technologies into manned vehicle convoy operations. The semi‐autonomous mobility system was associated with significantly better performance in several aspects of operator situational awareness and convoy integrity, including enhanced target identification, improved maintenance of following distance, and improved performance for unanticipated stops. This experiment also highlighted a critical human factors issue associated with the incorporation of autonomy in real‐world applications: participants felt that, overall, they outperformed the semi‐autonomous system on the simulated convoy operation. The operator's perception of the system's performance could potentially affect his or her willingness to use the system in real‐world applications. This experiment demonstrated that enhancements to overall system performance in real‐world applications are achieved by considering both technological and human factors solutions. Published 2008 Wiley Periodicals, Inc.*This article is a US Government work and, as such, is in the public domain of the United States of America.

Sequential Monte Carlo Methods for Tracking Multiple Targets With Deterministic and Stochastic Constraints

In multitarget scenarios, kinematic constraints from the interaction of targets with their environment or other targets can restrict target motion. Such motion constraint information could improve tracking performance if effectively used by the tracker. In this paper, we propose three particle filtering methods that incorporate constraint information in their proposal and weighting process; the number of targets is fixed and known in all methods. The reproposed constrained motion proposal (RCOMP) utilizes an accept/reject method to propose particles that meet the constraints. The truncated constraint motion proposal (TCOMP) uses proposal densities truncated to satisfy the constraints. The constraint likelihood independent partitions (CLIP) method simply rejects proposed partitions that do not meet the constraints. We use simulation to evaluate the performance of these three methods for two constrained motion scenarios: a vehicle convoy and soldiers executing a leapfrog motion. Moreover, we demonstrate the utility of constraint information by comparing the proposed algorithms with the independent partition (IP) proposal method that does not use constraint information. The simulation results demonstrate that the root mean square error (RMSE) tracking performance of the RCOMP and the TCOMP methods is much better than the CLIP and IP methods; this is due to their more efficient proposal process.

Extended Object Tracking Using Monte Carlo Methods

This correspondence addresses the problem of tracking extended objects, such as ships or a convoy of vehicles moving in urban environment. Two Monte Carlo techniques for extended object tracking are proposed: an interacting multiple model data augmentation (IMM-DA) algorithm and a modified version of the mixture Kalman filter (MKF) of Chen and Liu , called the mixture Kalman filter modified (MKFm). The data augmentation (DA) technique with finite mixtures estimates the object extent parameters, whereas an interacting multiple model (IMM) filter estimates the kinematic states (position and speed) of the manoeuvring object. Next, the system model is formulated in a partially conditional dynamic linear (PCDL) form. This affords us to propose two latent indicator variables characterizing, respectively, the motion mode and object size. Then, an MKFm is developed with the PCDL model. The IMM-DA and the MKFm performance is compared with a combined IMM-particle filter (IMM-PF) algorithm with respect to accuracy and computational complexity. The most accurate parameter estimates are obtained by the DA algorithm, followed by the MKFm and PF.

Point-to-point control and trajectory tracking in wheeled mobile robots: some further results and applications

This paper extends previous results in the framework of vehicle control. In particular the paper proposes simple control schemes for driving the vehicle from a given configuration to a prescribed posture in the configuration space, for tracking a time parameterizing path, and for driving a group of vehicles in convoy. We consider the point-to-point and tracking control problems when the controller accounts for the actuator dynamics.

Stable Control of Vehicle Convoys for Safety and Comfort

This note is concerned with the selection of control parameters to ensure string stability of a vehicle convoy system, while satisfying constraints imposed by considerations of safety and passenger comfort. Several forms of control law are investigated, including single and multiple look-ahead strategies as well as bi-directional control. By considering simple models, typical conditions for achieving collision avoidance and jerk limitation, while maintaining stability, are derived

DISTURBANCE DECOUPLING CONTROL OF HEAVY-DUTY VEHICLE STOP AND GO CRUISE SYSTEMS

A vehicle cruise system is modeled by integrating the dynamics characters of heavy-duty vehicle and vehicle convoy consisting two vehicles on low speed condition. Based on the model, the nonlinear disturbance decoupling theory is applied to separate the desired control object (inter vehicles relative distance and velocity) from the disturbance of leading vehicle's ace/deceleration, and realize the linearization of nonlinear system simultaneously. By adopting this decoupling linear subsystem, a developed stop and go cruise control systems is proposed. Computer simulation are conducted to illustrate the performance of control systems, the test results show that not only satisfying dynamic response characteristics are obtained, but also global decoupling from disturbance of leading vehicle's ace/deceleration can be realized. The simulating calculation verifies the effect of the control.

Convoy Dynamics with Bidirectional Flow of Control Information

The concept of platoon stability is investigated for a convoy of vehicles, each having a local controller which can use information about the motion of those both behind and ahead of it. Conditions on the control parameters are obtained, such that platoon stability can be ensured while simultaneously enabling the intervehicular spacing to be kept independent of velocity. Simulation results, illustrating the response of the convoy to a change in velocity of the lead vehicle, are also presented.

High Performance Knowledge Bases: four approaches to knowledge acquisition, representation and reasoning for workaround planning

As part of the DARPA-sponsored High Performance Knowledge Bases program, four organisations were set the challenge of solving a selection of knowledge-based planning problems in a particular domain, and then modifying their systems quickly to solve further problems in the same domain. The aim of the exercise was to test the claim that, with the latest AI technology, large knowledge bases can be built quickly and efficiently. The domain chosen was ‘workarounds’; that is, planning how a convoy of military vehicles can ‘work around’ (i.e. circumvent or overcome) obstacles in their path, such as blown bridges or minefields. This paper describes the four approaches that were applied to solve this problem. These approaches differed in their approach to knowledge acquisition, in their ontology, and in their reasoning. All four approaches are described and compared against each other. The paper concludes by reporting the results of an evaluation that was carried out by the HPKB program to determine the capability of each of these approaches.

Design Methodology and Modelling of Mechatronic Systems, Exemplified by a Novel Approach to Vehicle Convoy Driving

Systematic development of a novel product begins with the derivation of decisive objectives and product functions from the demands on the product. For a fulfillment of the product functions, principle solutions will be selected whose structures and parameters of specification will be laid out in a modelling process. The special features of the design methodology with mechatronic products will be exemplified by the product class control of vehicle dynamics. An integrated modelling of mechatronic product functions and principle solutions, combined with a hierarchical structuring of mechatronic systems, will be proposed. The methodology will be demonstrated on a passenger car with a control of lateral and longitudinal dynamics, modelled with the help of the design software CAMeL.