Longitudinal Control of Automated Guideway Transit Vehicles Within Platoons

1978 ◽  
Vol 100 (4) ◽  
pp. 302-310 ◽  
Author(s):  
S. E. Shladover
Keyword(s):  
Control System ◽  
Asymptotic Stability ◽  
Nonlinear Effects ◽  
Longitudinal Control ◽  
Describing Functions

This paper demonstrates, via analysis and simulation, the feasibility of a vehicle-follower control system which maintains intervehicular spacings of 30–60 cm within platoons of automated guideway transit (AGT) vehicles. Asymptotic stability of the platoon is shown to be achievable when each vehicle references its speed to that of the platoon leader. Jerk limiting, which is regarded as essential for all AGT longitudinal controllers, is shown to be potentially destabilizing. The nonlinear effects produced by the jerk limiter are analyzed by use of describing functions, and it is demonstrated how the undesirable effects can be avoided.

Vehicle-Follower Control for Dynamic Entrainment of Automated Guideway Transit Vehicles

1979 ◽  
Vol 101 (4) ◽  
pp. 314-320 ◽  
Author(s):  
S. E. Shladover
Keyword(s):  
Control System ◽  
Asymptotic Stability ◽  
Response Speed ◽  
Continuous Functions ◽  
Control Law ◽  
Longitudinal Control ◽  
Linear Controller ◽  
Vehicle Platoons ◽  
Nonlinear Control Law ◽  
Disturbance Estimator

This paper describes a method of vehicle-follower longitudinal control which has been developed to enable automated guideway transit (AGT) vehicles to join (entrain) and leave (extrain) trains or close-formation platoons (at 30 cm spacings) while traveling at cruise speed. Because a linear controller cannot be designed to have the accuracy and response speed needed for operations at very close inter-vehicular spacings without producing excessive control action at large spacings, the suggested controller is a nonlinear vehicle follower in which the gains are continuous functions of the spacing between the vehicles. The nonlinear control law is defined and its simulated behavior in a typical dynamic entrainment is shown. Sample simulated responses of nine-vehicle platoons demonstrate the asymptotic stability which the control system must have to be applicable for long platoons. The use of a disturbance estimator to resist external force loadings and the implementation of the control system using sampled, smoothed data are explained and demonstrated via simulation.

Design and Experimental Implementation of Longitudinal Control for a Platoon of Automated Vehicles

1998 ◽  
Vol 122 (3) ◽  
pp. 470-476 ◽  
Author(s):  
R. Rajamani ◽  
S. B. Choi ◽  
B. K. Law ◽  
J. K. Hedrick ◽  
R. Prohaska ◽  
...  
Keyword(s):  
Control System ◽  
Torque Converter ◽  
Stable Operation ◽  
Automated Vehicles ◽  
Longitudinal Control ◽  
The Public ◽  
Automated Highways ◽  
Experimental Implementation ◽  
Special Challenge ◽  
Upper Level

This paper presents the design and experimental implementation of a longitudinal control system for the operation of automated vehicles in platoons. The control system on each vehicle is designed to have a hierarchical structure and consists of an upper level controller and a lower level controller. The upper controller determines the desired acceleration for each vehicle in the platoon so as to maintain safe string-stable operation even at very small intervehicle spacing. The lower controller utilizes vehicle-specific parameters and determines the throttle and/or brake commands required to track the desired acceleration. A special challenge handled in the design of the lower level controller is low-speed operation that involves gear changes and torque converter dynamics. The paper also presents the design of longitudinal intra-platoon maneuvers that are required in order to allow any car in the platoon to make an exit. The paper presents extensive experimental results from the public NAHSC demonstration of automated highways conducted in August 1997 at San Diego, California. The demonstration included an eight-car platoon operating continuously over several weeks with passenger rides given to over a thousand visitors. The maneuvers demonstrated included starting the automated vehicles from complete rest, accelerating to cruising speed, allowing any vehicle to exit from the platoon, allowing new vehicles to join the platoon and bringing the platoon to a complete stop at the end of the highway. [S0022-0434(00)01903-1]

Implementation and vehicle tests of a vehicle stop-and-go cruise control system

2002 ◽  
Vol 216 (7) ◽  
pp. 537-544 ◽  
Author(s):  
K Yi ◽  
N Ryu ◽  
H J Yoon ◽  
K Huh ◽  
D Cho ◽  
...  
Keyword(s):  
Control System ◽  
Control Algorithm ◽  
Speed Control ◽  
Step Motor ◽  
Cruise Control ◽  
Longitudinal Control ◽  
Linear Quadratic Optimal Control ◽  
Millimetre Wave ◽  
Stop And Go ◽  
Wave Radar

Implementation and vehicle tests of a vehicle longitudinal control algorithm for stop-and-go cruise control have been performed. The vehicle longitudinal control scheme consists of a set-speed control algorithm, a speed control algorithm, and a distance control algorithm. A desired acceleration for the vehicle for the control of vehicle-to-vehicle relative speed and clearance has been designed using linear quadratic optimal control theory. Performance of the control algorithm has been investigated via vehicle tests. Vehicle tests have been conducted using two test vehicles. A 2000 cm3 passenger car equipped with a radar distance sensor, throttle/brake actuators and a controller has been used as a subject vehicle in the vehicle tests. A millimetre wave radar sensor has been used for distance measurement. A step motor and an electronic vacuum booster have been used for throttle/brake actuators. It has been shown that the implemented vehicle longitudinal control system can provide satisfactory performance in vehicle set-speed control and vehicle clearance control at lower speeds.

Performance of the Virgo interferometer longitudinal control system during the second science run

2011 ◽  
Vol 34 (7) ◽  
pp. 521-527 ◽  
Author(s):  
T. Accadia ◽  
F. Acernese ◽  
F. Antonucci ◽  
P. Astone ◽  
G. Ballardin ◽  
...  
Keyword(s):  
Control System ◽  
Longitudinal Control

scholarly journals On the asymptotic stability of advection-diffusion equations of mass transport in a bubble column bioreactor

2021 ◽  
Vol 2090 (1) ◽  
pp. 012035
Author(s):  
Paola Lecca ◽  
Angela Re
Keyword(s):  
Acetic Acid ◽  
Control System ◽  
Asymptotic Stability ◽  
Bubble Column ◽  
Bubble Column Reactor ◽  
Dissolved Gas ◽  
Advection Diffusion Equation ◽  
Bubble Column Bioreactor ◽  
Advection Diffusion ◽  
By Products

Abstract This study presents an asymptotic stability analysis of a model of a bioreactor converting carbon monoxide (CO) gas into ethanol through a C. autoethanogenum biocatalyst. The configuration is a bubble column reactor with co-current gas-liquid flows where gas feed is introduced by a gas distributor placed at the bottom of the column. A pure culture of C. autoethanogenum is subsequently injected at the bottom of the column; therein, cells are dispersed in the liquid and consume the dissolved gas and release by-products such as ethanol and acetic acid. Cellular growth and byproduct secretion are affected by spatially varying dissolved gas concentrations due to advection-diffusion mass transports which are induced by the effect of the injection pressure and gravitational force. The model accounts for four species representing the biomass, the CO substrate in the liquid phase, and two by-products - ethanol and acetic acid. Substrate dynamics is described by an advection-diffusion equation. We investigate the asymptotic stability of the biomass dynamics that is a requirement for the system’s controllability, i.e. for the possibility to steer a dynamical system from an arbitrary initial state to an arbitrary final state using a set of controls. The concept of stability of the controls is extremely relevant to controllability since almost every workable control system is designed to be stable. If a control system is not stable, it is usually of no use in practice in industrial processes. In the case of a bioreactor, the control is the biomass and controllability is the possibility of modulating through this control the ethanol production. We present a test for asymptotic stability, based on the analysis of the properties of the dynamic function defining its role as storage function.

Multiple Fault Diagnosis as Applied to Automated Vehicle Control

1999 ◽  
Author(s):  
Adam S. Howell ◽  
J. Karl Hedrick
Keyword(s):  
Control System ◽  
Diagnostic System ◽  
Vehicle Control ◽  
Longitudinal Control ◽  
Multiple Faults ◽  
Automated Vehicle ◽  
Multiple Fault Diagnosis ◽  
System Components ◽  
Automated Vehicle Control ◽  
Residual Processing

Abstract This paper addresses the problem of detecting multiple faults for the longitudinal control system of an automated vehicle. An existing fault diagnostic system which can isolate all single faults is extended to the diagnosis of multiple faults via improved residual processing in the form of fuzzy logic. The new diagnostic system is shown to correctly detect and isolate all single and multiple faults in a subset of the automated vehicle control system components.

The Development of a Longitudinal Control System for a Sports-Utility-Vehicle

2013 ◽  
Author(s):  
Herman Hamersma ◽  
Schalk Els
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Lateral Acceleration ◽  
Longitudinal Control ◽  
Test Vehicle ◽  
Acceleration Vector ◽  
Land Rover ◽  
Simulation Results ◽  
Utility Vehicle ◽  
High Center

A common problem with sports-utility-vehicles is the low rollover threshold, due to a high center of gravity. Instead of modifying the vehicle to increase the rollover threshold, the aim of the control system is to prevent the vehicle from exceeding speeds that would cause the vehicle to reach its rollover threshold. The aim of the autonomous longitudinal control system, discussed here, is to improve the vehicle’s safety by controlling the vehicle’s longitudinal behavior. In order to develop a control system that autonomously controls the longitudinal degree of freedom, an experimentally validated mathematical model of the test vehicle (a 1997 Land Rover Defender 110 Wagon) was used — the model was developed in MSC.ADAMS/View. The control system was developed by generating a reference speed that the vehicle must track. This reference speed was formulated by taking into account the vehicle’s limits due to lateral acceleration, combined lateral and longitudinal acceleration and the vehicle’s performance capabilities. The MSC.ADAMS/View model of the test vehicle was used to evaluate the performance of the control system on various racetracks for which the GPS coordinates were available. The simulation results indicate that the control system performed as expected by limiting the vehicle’s acceleration vector to the prescribed limits.

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