We consider the problem of cooperation among a collection of vehicles performing a shared task using intervehicle communication to coordinate their actions. Tools from algebraic graph theory prove useful in modeling the communication network and relating its topology to formation stability. We prove a Nyquist criterion that uses the eigenvalues of the graph Laplacian matrix to determine the effect of the communication topology on formation stability. We also propose a method for decentralized information exchange between vehicles. This approach realizes a dynamical system that supplies each vehicle with a common reference to be used for cooperative motion. We prove a separation principle that decomposes formation stability into two components: Stability of this is achieved information flow for the given graph and stability of an individual vehicle for the given controller. The information flow can thus be rendered highly robust to changes in the graph, enabling tight formation control despite limitations in intervehicle communication capability.

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Information flow and cooperative control of vehicle formations

Key features of one automated intelligent vehicle/highway system (IVHS) are outlined, it is shown how core driver decisions are improved, a basic IVHS control system architecture is proposed, and a design of some control subsystems is offered. Some experimental work is summarized. A system that promises a threefold increase in capacity is outlined, and a four-layer hierarchical control architecture that decomposes this problem into more manageable units is proposed. >

Smart cars on smart roads: problems of control

Intelligent vehicles have increased their capabilities for highly and, even fully, automated driving under controlled environments. Scene information is received using onboard sensors and communication network systems, i.e., infrastructure and other vehicles. Considering the available information, different motion planning and control techniques have been implemented to autonomously driving on complex environments. The main goal is focused on executing strategies to improve safety, comfort, and energy optimization. However, research challenges such as navigation in urban dynamic environments with obstacle avoidance capabilities, i.e., vulnerable road users (VRU) and vehicles, and cooperative maneuvers among automated and semi-automated vehicles still need further efforts for a real environment implementation. This paper presents a review of motion planning techniques implemented in the intelligent vehicles literature. A description of the technique used by research teams, their contributions in motion planning, and a comparison among these techniques is also presented. Relevant works in the overtaking and obstacle avoidance maneuvers are presented, allowing the understanding of the gaps and challenges to be addressed in the next years. Finally, an overview of future research direction and applications is given.

A Review of Motion Planning Techniques for Automated Vehicles

This paper addresses the problem of coordinating multiple spacecraft to fly in tightly controlled formations. The main contribution of the paper is to introduce a coordination architecture that subsumes leader-following, behavioral, and virtual-structure approaches to the multiagent coordination problem. The architecture is illustrated through a detailed application of the ideas to the problem of synthesizing a multiple spacecraft interferometer in deep space.

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A coordination architecture for spacecraft formation control

The accomplishments to date on the development of automatic vehicle control technology in the Program on Advanced Technology for the Highway (PATH) at the University of California, Berkeley, are summarized. The basic principles and assumptions underlying the PATH work are identified, and the work on automating vehicle lateral (steering) and longitudinal (spacing and speed) control is explained. For both lateral and longitudinal control, the modeling of plant dynamics is described, and the development of the additional subsystems needed (communications, reference/sensor systems) and the derivation of the control laws are presented. Plans for testing on vehicles in both near and long term are discussed. >

Automated vehicle control developments in the PATH program

This paper presents a systematic analysis of a longitudinal control law for a platoon of non-identical vehicles using a non-linear model to represent the vehicle dynamics of each vehicle within the platoon. The basic idea is to take full advantage of recent advances in communication and measurement and using these advances in longitudinal control of a platoon of vehicles: in particular, we assume that for i = 1,2,... vehicle i knows at all times v l and al (the velocity and acceleration of the lead vehicle) in addition to the distance between vehicle i and the preceding vehicle, i - 1.

Longitudinal Control of a Platoon of Vehicles

The paper considers the problem of longitudinal control of a platoon of automotive vehicles on a straight lane of a highway and proposes control laws in the event of loss of communication between the lead vehicle and the other vehicles in the platoon. After discussing the main design objectives for the proposed control laws, the authors formulate these objectives as a constrained optimization problem. By solving this optimization problem, they obtain longitudinal control laws for a platoon of vehicles which does not use any communication from the lead vehicle to the other vehicles in the platoon. Comparison between these control laws and the control laws which use such a communication link to transmit lead-vehicle information to the other vehicles in a platoon shows that, in the case of loss of communication between the lead vehicle and the other vehicles, the performance of the longitudinal control laws degrades; however, this degradation is not catastrophic. >

Longitudinal control of a platoon of vehicles with no communication of lead vehicle information: a system level study

Evaluates the performance of longitudinal control laws with no communication of lead vehicle information. After using exact linearization methods, the authors propose a linear control law for each vehicle which uses only the information from the preceding vehicle in the platoon.

Longitudinal Control of a Platoon of Vehicles with no Communication of Lead Vehicle Information

This paper presents a preliminary system study of a longitudinal control law for a platoon of nonidentical vehicles using a simplified nonlinear model for the vehicle dynamics This study advances the art of automatic longitudinal control for a platoon of vehicles in the sense that is considers longer platoons composed of nonidentical vehicles; furthermore, the longitudinal control laws presented in this study take advantage of communication possibilities not available in the recent past

Shahab Sheikholeslam

Papers

Automated vehicle control developments in the PATH program

Longitudinal Control of a Platoon of Vehicles

Longitudinal control of a platoon of vehicles with no communication of lead vehicle information: a system level study

Longitudinal Control of a Platoon of Vehicles with no Communication of Lead Vehicle Information

A system level study of the longitudinal control of a platoon of vehicles