Method and apparatus for braking rail-guided vehicles automatically and accurately with respect to a deceleration distance

• US 4,190,220 A
• Filed: 02/23/1978
• Issued: 02/26/1980
• Est. Priority Date: 02/23/1977
• Status: Expired due to Term

• Current Assignee: Licentia Patent-Verwaltungs-GmbH
• Original Assignee: Licentia Patent-Verwaltungs-GmbH
• Inventors: Hahn, Karl, Strecker, Johannes, Bohms, Herbert, Landes, Wilhelm
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Application Number:
  US05/880,457
• Time in Patent Office: 733 Days
• Field of Search: 104/149, 104/152, 104/153, 246/63, 246/167 R, 246/182 R, 246/182 B, 246/187 R, 246/187 B, 364/426
• US Class Current: 246/182.00B
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 7/00 Electrodynamic brake systems for vehicles in general
• CPC Class Codes: B60T 7/128 Self-acting brakes of different types for railway vehicles B60T7/12 takes precedence; self-acting brakes in general F16D59/00

Abstract

The method uses a computer which, in accordance with a function based on either time or distance of deceleration, delivers speed values to a control apparatus for the braking force of the vehicle. The control apparatus is utilized to deliver correcting control signals for correcting the braking forces, and a fixed braking force control signal is provided and has a magnitude which is rated for a braking which is accurate as to the deceleration distance under conditions of an ideal track and an average train length, as when the rail-guided vehicles are locomotive-drawn railroad trains. The correcting control signals are combined, after a first time delay and in the correct mathematical polarity, or relationship, to the fixed braking force control signal. Upon actuation of the vehicle brake, only the fixed braking force control signal is applied and the computer is actuated for picking up and storing the actual speed at this instant. It is only after the expiration of a first delay time that the computer proceeds to compute the reference speed or correcting speed values while starting from the stored actual speed as the initial reference value, and the control apparatus is enabled only after a second delay time has expired. As the actual speed approaches the desired speed, following deceleration, the fixed braking force control signal is switched off at a differential period of time in advance and the connections are changed from the reference speed values of the computer to the desired speed as a new reference value. The apparatus includes a differential amplifier to which are applied the desired speed value and the actual speed value and which controls a limit-value stage switch, upon exceeding a threshold value, actuates the computer and brings a first switching element, following the computer, and a second switching element, into closed positions. The first switching element is connected to one input and the desired speed is applied to the other input of a maximum evaluator whose output is connected to a braking force controller which is controlled by the evaluator output and by the actual speed and which is further actuable, with delay, by the computer. The braking force controller delivers braking force control signals to a summing point to which a fixed basic braking force control signal is applied through the second switching element.

Claims

1. A method of braking a rail vehicle from a first speed to a target speed in a predetermined distance, said method comprising the steps of:

generating a predetermined, fixed braking force upon actuation of a vehicle brake, generating a first, fixed braking force signal that has an amplitude corresponding to said braking force;

generating a second signal corresponding to the actual speed of said vehicle;

delaying said second signal for a first delay time;

generating a third signal corresponding to reference speed values, said third signal having an initial maximum value corresponding to the delayed value of the signal corresponding to the actual speed of said vehicle at the time the brake is applied;

generating, after a predetermined second delay time, a correcting braking force to modify the rate of change of speed of said vehicle to reach said target speed within said distance;

combining said correcting braking force with said predetermined, fixed braking forces after said second delay time;

removing said predetermined, fixed braking force when said vehicle slows down to a speed that differs from said target speed by a predetermined amount;

thereupon generating a new correcting braking force based on the target speed; and

applying said new braking force to brake said vehicle to said target speed.

2. In a method of braking rail-guided vehicles, as claimed in claim 1, the step of:

switching off the fixed basic braking force control signal a predetermined period of time in advance of coincidence between the actual speed and the target speed as the actual speed approaches the target speed to be attained at the end of the deceleration distance.

3. In a method of braking rail-guided vehicles, as claimed in claim 2, effecting the switching to the target speed in a smooth transition in proportion to the average brake-release time.

4. In a method of braking rail-guided vehicles, as claimed in claim 3, effecting such smooth transition by following a substantially exponential function.

5. In apparatus for braking rail-guided vehicles automatically and accurately with respect to a deceleration distance, while using a computer which, in accordance with a function based on one of the time and the distance of deceleration, delivers speed values to a means controlling the braking force of the vehicle, the improvement comprising, in combination:

a differential amplifier having respective inputs receiving first and second signal corresponding, respectively, to the target speed value and the actual speed value;

a limit-value stage connected to and controlled by said differential amplifier;

a first switching element connected to the output of said computer;

a second switching element;

said limit-value stage, upon receiving a signal exceeding a threshold value, actuating said computer and bringing said first and second switching elements into closed positions;

a maximum evaluator having a pair of inputs;

means connecting said first switching element to one input of said maximum evaluator;

means applying the desired speed to the other input of said maximum evaluator;

a braking force controller connected to and controlled by the output of said maximum evaluator;

means supplying the actual speed to said braking force controller;

said braking force controller being actuable by said computer;

said braking force controller delivering braking force control signals to a summing point; and

means providing a fixed basic braking force control signal to said second switching element, said second switching element, when in its closed position, supplying said fixed basic braking force control signal to said summing point.

6. In apparatus for braking rail-guided vehicles, the improvement claimed in claim 5, in which the threshold value of said limit-value stage is controllable through the braking force of the vehicle.

7. In apparatus for braking rail-guided vehicles, the improvement claimed in claim 5, including a capacitor and a resistor shunting the inputs of said maximum evaluator.