TY - JOUR
T1 - Control of freeway traffic flow in unstable phase by H∞ theory
AU - Chiang, Yi Hsien
AU - Juang, Jyh Ching
N1 - Funding Information:
Manuscript received December 29, 2005; revised November 8, 2006, March 7, 2007, and March 16, 2007. This work was supported by the National Science Council, Taiwan, R.O.C., under Grant NSC93-2213-E-006-133. The Associate Editor for this paper was M. Papageorgiou.
PY - 2008/6
Y1 - 2008/6
N2 - This paper devises a freeway controller that is capable of stabilizing traffic flow when the traffic system is in the unstable (congested) phase, in which a shock wave is likely to occur in the presence of any inhomogeneity and where the system is on the verge of a jam condition. Two types of traffic controllers are developed through the use of either a speed command approach that can be implemented in an intelligent transportation system (ITS) or ramp metering that is a typical way of preventing a freeway from overloading. By means of the feedback linearization technique, the discretized macroscopic traffic flow model is reformulated, in which the desired change of volume in each section is treated as a virtual input. By exploring the casual relations among density, speed, and flow change, the corresponding speed commands can be determined. The traffic flow control problem is formulated as an H∞ control design problem so that uncertainties that are associated with the macroscopic model can be taken into account. Simulations show that the devised controller can effectively stabilize the traffic flow in the unstable phase. Design flexibilities associated with the method are also discussed.
AB - This paper devises a freeway controller that is capable of stabilizing traffic flow when the traffic system is in the unstable (congested) phase, in which a shock wave is likely to occur in the presence of any inhomogeneity and where the system is on the verge of a jam condition. Two types of traffic controllers are developed through the use of either a speed command approach that can be implemented in an intelligent transportation system (ITS) or ramp metering that is a typical way of preventing a freeway from overloading. By means of the feedback linearization technique, the discretized macroscopic traffic flow model is reformulated, in which the desired change of volume in each section is treated as a virtual input. By exploring the casual relations among density, speed, and flow change, the corresponding speed commands can be determined. The traffic flow control problem is formulated as an H∞ control design problem so that uncertainties that are associated with the macroscopic model can be taken into account. Simulations show that the devised controller can effectively stabilize the traffic flow in the unstable phase. Design flexibilities associated with the method are also discussed.
UR - http://www.scopus.com/inward/record.url?scp=45249086797&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=45249086797&partnerID=8YFLogxK
U2 - 10.1109/TITS.2008.922875
DO - 10.1109/TITS.2008.922875
M3 - Article
AN - SCOPUS:45249086797
VL - 9
SP - 193
EP - 208
JO - IEEE Transactions on Intelligent Transportation Systems
JF - IEEE Transactions on Intelligent Transportation Systems
SN - 1524-9050
IS - 2
M1 - 4515875
ER -