STATE ESTIMATION IN LONG FREIGHT TRAINS

Handling of very long multipowered freight trains needs closed loop controllers for throttling and braking that are superposed to a given off-line schedule. The objective of the controller's action is mainly to minimize velocity and coupler force deviations from nominal values due to gravity and other disturbances. Controllers studied for that purpose assume the capability of transmitting information along the train and need to know the actual locomotive and car velocities as well as the coupling forces. As only a small number of these states are actually measured, often the locomotive velocities only, an observer for the estimation of the other states is necessary. Although the observer design is made easier by a linearization of the train model around the nominal values, the high order of the system makes the design of a usual reduced observer awkward and the dimension of the observer will be too high to be of any practical value. The object of this paper is to develop a low order observer that reconstructs the dominant modes of the system. In order to keep the design general, the lumped parameter train model is approximated by a distributed parameter model, that matches the dominant modes sufficiently well. The advantage of such an approach is that analytical expressions are found for the eigenvalues and eigenfunctions of the system, that enable a straightforward representation of the dominant modes. The design of the feedback matrix of the observer is based on a simple structure that needs only the locomotive velocities. The coefficients of the feedback matrix are found by applying a suboptimal design using a quadratic objective function. It is shown that this choice of observer feedback results in a fast reconstruction of the states. Simulation results show the transient behaviour of the designed observer and its performance under various dynamic situations for different train lengths (system orders) and observer orders.

• Corporate Authors:

  Canadian Institute of Guided Ground Transport

  Queen's University
  Kingston, Ontario K7L 3N6,   Canada 

  Queen's University, Ontario

  Department of Electrical Engineering
  Kingston, Ontario  Canada  K7L 3N6

  Social Sciences & Humanities Res Council of Canada

  255 Albert Street, P.O. Box 1610
  Ottawa, ONo,   Canada 
• Authors:
  • Gruber, P
  • Bayoumi, M M
• Publication Date: 1980-4

Media Info

• Features: Figures; References;
• Pagination: 110 p.

Subject/Index Terms

• TRT Terms: Braking; Control; Couplers; Data communications; Electric circuits; Force; Instruments for measuring speed or velocity; Mathematical models; Multiple unit trains; Radio control; Slave locomotives; Speed control; Train operations
• Old TRIS Terms: Braking control; Long trains; Slack action; Slave locomotive control; Speed measuring devices; Trainlines
• Subject Areas: Railroads; Vehicles and Equipment;

Filing Info

• Accession Number: 00324496
• Record Type: Publication
• Report/Paper Numbers: CIGGT 79-21
• Files: TRIS
• Created Date: Feb 18 1981 12:00AM