Method and apparatus for controlled braking in fixed guideway transportation systems

• US 8,744,652 B1
• Filed: 12/09/2011
• Issued: 06/03/2014
• Est. Priority Date: 12/10/2010
• Status: Active Grant

• Current Assignee: Cybertron International Incorporated
• Original Assignee: Cybertron International Incorporated
• Inventors: Nishinaga, Eugene Iwao, Burt, Harry
• Primary Examiner(s): Algahaim, Helal A
• Assistant Examiner(s): Hilgendorf, Dale W
• Application Number:
  US13/316,398
• Time in Patent Office: 907 Days
• Field of Search: 701/19, 701/96, 701/20, 701/301, 701/93, 701/24, 701/118, 701/117, 701/70, 104/124, 104/282, 104/284, 104/285, 104/283, 104/286, 104/294, 104/292, 104/290, 104/88.02, 104/23.2, 104/155, 180/169, 180/170, 188/38, 188/41, 188/162, 188/170, 246/122.R, 246/167.D, 246/28.R, 246/182.R, 246/121, 246/1.R, 246/5, 246/4, 342/71, 340/479, 340/436, 340/467, 303/7, 303/123, 303/28, 303/118.1, 303/132, 303/15, 303/146, 105/30, 105/64.2, 105/1.4
• US Class Current: 701/20
• CPC Class Codes: B60T 13/665 the systems being specially adapted for transferring two or more command signals, e.g. railway systems B60T13/662 takes precedence
• CPC Class Codes: B60T 17/228 for railway vehicles
• CPC Class Codes: B60T 8/1705 for rail vehicles
• CPC Class Codes: B60T 8/321 deceleration B60T8/34, B60T8/52, B60T8/54, B60T8/56, B60T8/58, B60T8/72, B60T8/86, B60T8/88 take precedence
• CPC Class Codes: B60T 8/3235 Systems specially adapted for rail vehicles
• CPC Class Codes: B60T 8/345 having more than one brake circuit per wheel
• CPC Class Codes: B61H 9/006 Brakes for locomotives
• CPC Class Codes: B61L 23/34 for indicating the distance between vehicles or trains by the transmission of signals therebetween
• CPC Class Codes: B61L 3/00 Devices along the route for controlling devices on the vehicle or train, e.g. to release brake or to operate a warning signal

Abstract

The present invention relates generally to ground transportation systems, and more particularly to a fixed guideway transportation system that achieves a superior cost benefit ratio, is lower in net present cost and thus more easily justified for lower density corridors, and can provide passenger carrying capacities appropriate for higher density corridors serviced by mass rapid transit systems today. According to certain aspects, the present invention provides a braking control system and methodology that enables the implementation of related systems and methods that achieve safe headways at higher speeds than conventionally possible, while maintaining collision avoidance capabilities that support necessary MTBH criteria. In embodiments, a brake assembly for an axle of a vehicle provides redundancy and load-sharing such that failures are guaranteed to not occur above required safety criteria.

Claims

1. A braking apparatus for a fixed guideway vehicle, comprising:

a plurality of braking mechanisms coupled to a single axle of the vehicle;

a plurality of controllers that respectively and independently control the braking mechanisms; and

a bus for communicating information between the plurality of controllers,

wherein each of the plurality of controllers includes a feedback control function that independently monitors the combined operation of the braking mechanisms and determines error information for each of the braking mechanisms and combines the error information, the combined error information comprising a difference value between a targeted braking rate for the vehicle and an actual measured braking rate for the vehicle, and

wherein each of the plurality of controllers uses the difference value in the error information from the feedback control function to independently calculate a braking force value to be applied by the respective braking mechanisms that will cause the targeted braking rate for the vehicle.

2. The braking apparatus according to claim 1, wherein a number and a braking capability of the plurality of braking mechanisms and controllers are selected to achieve an emergency braking rate for the vehicle despite failure of a predetermined number of the plurality of braking mechanisms and controllers.

3. The braking apparatus according to claim 2, wherein the selection is made in compliance with a targeted Mean Time Between Hazard (MTBH).

4. The braking apparatus according to claim 1, further comprising:

a plurality of sensors independently and respectively coupled to the controllers, each of the sensors determining one or more characteristics of movement of the vehicle,

wherein the controllers are configured to control operation of the braking mechanisms based at least partially on data from the sensors.

5. The braking apparatus according to claim 4, wherein the one or more characteristics include one or more of vehicle velocity and vehicle acceleration.

6. The braking apparatus according to claim 1, wherein the braking mechanisms are each capable of applying no more than 50% of the force required on one axle to brake a fully loaded vehicle.

7. The braking apparatus according to claim 1, wherein the error information includes a current difference between the targeted braking rate and the actual measured braking rate, and a current rate of change of difference between the targeted braking rate and the actual measured braking rate.

8. The braking apparatus according to claim 7, wherein the plurality of controllers use a proportional, integral and differential (PID) control algorithm to calculate the braking force using the current difference, current rate of change of difference and proportional, integral and differential gain constants.

9. A braking method for a fixed guideway vehicle, comprising:

coupling a plurality of braking mechanisms to a single axle of the vehicle;

respectively coupling a plurality of controllers to independently control the braking mechanisms;

communicating information between the plurality of controllers;

independently monitoring, by a feedback control function in each of the plurality of controllers, the combined operation of the braking mechanisms so as to determine error information comprising a difference value between a targeted braking rate for the vehicle for each of the braking mechanisms and combining the error information, the combined error information and an actual measured braking rate for the vehicle; and

configuring each of the controllers to use the difference value in the error information from the feedback control function to independently calculate a braking force value to be applied by the respective braking mechanisms that will cause the targeted braking rate for the vehicle.

10. The braking method according to claim 9, further comprising:

selecting a number and a braking capability of the plurality of braking mechanisms and controllers to achieve an emergency braking rate for the vehicle despite failure of a predetermined number of the plurality of braking mechanisms and controllers.

11. The braking method according to claim 10, wherein the selection is made in compliance with a targeted Mean Time Between Hazard (MTBH).

12. The braking method according to claim 9, further comprising:

respectively coupling a plurality of sensors to the controllers, each of the sensors determining one or more characteristics of movement of the vehicle,

wherein the controllers are configured to control operation of the braking mechanisms based at least partially on data from the sensors.

13. The braking method according to claim 12, wherein the one or more characteristics include one or more of vehicle motion and vehicle acceleration.

14. The braking method according to claim 9, further comprising configuring the braking mechanisms such that they are each capable of applying no more than 50% of the force required on one axle to brake a fully loaded vehicle.

15. A method of controlling movement of fixed guideway vehicles in a system, comprising:

providing a plurality controllers for each of the respective braking apparatuses in each of the vehicles;

configuring the controllers to cause a targeted braking rate for each of the vehicles based on a command from a master controller, wherein the controllers cause the braking apparatuses to apply a calculated amount of braking force that will cause the targeted braking rates for each of the vehicles, wherein the targeted braking rates are calculated based on a combined operation of the braking apparatuses for each vehicle and combined error information from the respective error information of each braking apparatus;

monitoring separation between the vehicles;

calculating the targeted braking rate based on the monitored separation;

generating the command based on the calculated targeted braking rate; and

calculating a stopping distance delta between the vehicles based on the monitored separation and the targeted braking rate, wherein calculating includes determining a best case stopping distance of a leading vehicle and the worst case stopping distance of a following vehicle whose path includes the leading vehicle.