Vehicle control system and method

Abstract

A vehicle control system includes a controller to receive a current commanded speed, determine a current moving speed, and calculate a reference shaped speed to operate a propulsion system and/or a brake system to cause the current moving speed to approach the current commanded speed. The reference speed is based on a reference shaping model that changes the reference speed based on relative values of the current commanded speed, a previous commanded speed, the current moving speed, and a previous reference shaped speed. The controller controls the propulsion system and/or the brake system to cause the vehicle system to move at the calculated reference shaped speed. A method includes receiving a current commanded speed, determining a current moving speed, calculating a reference shaped speed, and controlling the one or more of the propulsion system or the brake system to cause the vehicle system to move at the reference shaped speed.

What is claimed is: 
     
         1 . A vehicle control system comprising:
 a controller configured to receive a current commanded speed that a vehicle system is to move, the controller also configured to determine a current moving speed at which the vehicle system is moving and to calculate a reference shaped speed at which one or more of a propulsion system or a brake system of the vehicle system is directed to operate to cause the current moving speed of the vehicle system to approach the current commanded speed,   the reference speed determined by the controller based on a reference shaping model that changes the reference speed based on relative values of the current commanded speed, a previous commanded speed that the vehicle system previously was commanded to move, the current moving speed of the vehicle system, and a previous reference shaped speed,   the controller configured to control the one or more of the propulsion system or the brake system to operate to cause the vehicle system to move at the reference shaped speed that is calculated.   
     
     
         2 . The vehicle control system of  claim 1 , wherein the controller is configured to calculate the reference shaped speed by linearly increasing or linearly decreasing a previous value of the reference shaped speed. 
     
     
         3 . The vehicle control system of  claim 1 , wherein the controller is configured to calculate the reference shaped speed by increasing or decreasing a previous value of the reference shaped speed at a rate that changes based on one or more of (a) a first difference between a current value of the reference shaped speed and the current commanded speed or (b) a second difference between the current moving speed of the vehicle system and one or more of the reference shaped speed or the current commanded speed. 
     
     
         4 . The vehicle control system of  claim 3 , wherein the controller is configured to calculate a faster value for the rate when the difference between the current value of the reference shaped speed and the current commanded speed is larger and a slower value when the difference between the current value of the reference shaped speed and the current commanded speed is smaller. The vehicle control system of  claim 3 , wherein the controller is configured to calculate a first designated value for the rate when the difference between the current value of the reference shaped speed and the current commanded speed is larger than a designated value and a second designated value for the rate that is slower than the first designated value when the difference between the current value of the reference shaped speed and the current commanded speed is no larger than the designated value. 
     
     
         6 . The vehicle control system of  claim 1 , wherein the controller is configured to calculate the reference shaped speed by increasing or decreasing a previous value of the reference shaped speed at a first rate then a faster, second rate, followed by a slower, third rate. 
     
     
         7 . The vehicle control system of  claim 1 , wherein the controller is configured to calculate the reference shaped speed by increasing or decreasing a previous value of the reference shaped speed according to a time invariant first order model. 
     
     
         8 . The vehicle control system of  claim 1 , wherein the controller is configured to calculate the reference shaped speed by changing a previous value of the reference shaped speed according to a rate that is based on one or more of a weight of the vehicle system and the current moving speed. 
     
     
         9 . The vehicle control system of  claim 1 , wherein the controller is configured to receive the current commanded speed from an operator input device. The vehicle control system of  claim 1 , wherein the controller is configured to receive the current commanded speed from an automated control system. 
     
     
         11 . A method comprising:
 receiving a current commanded speed that a vehicle system is to move;   determining a current moving speed at which the vehicle system is moving;   calculating a reference shaped speed at which one or more of a propulsion system or a brake system of the vehicle system is directed to operate to cause the current moving speed of the vehicle system to approach the current commanded speed, the reference speed determined based on a reference shaping model that changes the reference speed based on relative values of the current commanded speed, a previous commanded speed that the vehicle system previously was commanded to move, and the current moving speed of the vehicle system; and   controlling the one or more of the propulsion system or the brake system to operate to cause the vehicle system to move at the reference shaped speed that is calculated.   
     
     
         12 . The method of  claim 11 , wherein the reference shaped speed is calculated by linearly increasing or linearly decreasing a previous value of the reference shaped speed. 
     
     
         13 . The method of  claim 11 , wherein the reference shaped speed is calculated by increasing or decreasing a previous value of the reference shaped speed at a rate that changes based on a difference between a current value of the reference shaped speed and the current commanded speed. 
     
     
         14 . The method of  claim 13 , wherein the rate is faster when the difference between the current value of the reference shaped speed and the current commanded speed is larger and the rate is slower when the difference between the current value of the reference shaped speed and the current commanded speed is smaller. 
     
     
         15 . The method of  claim 13 , wherein the rate is a first designated rate when the difference between the current value of the reference shaped speed and the current commanded speed is larger than a designated value and the rate is a second designated rate that is slower than the first designated rate when the difference between the current value of the reference shaped speed and the current commanded speed is no larger than the designated value. 
     
     
         16 . The method of  claim 11 , wherein the reference shaped speed is calculated by increasing or decreasing a previous value of the reference shaped speed according to a time invariant first order model. 
     
     
         17 . The method of  claim 11 , wherein the reference shaped speed is calculated by changing a previous value of the reference shaped speed at a rate that changes based on one or more of a weight of the vehicle system and the current moving speed. 
     
     
         18 . The method of  claim 11 , wherein the current commanded speed is received from an operator input device or from an automated control system. 
     
     
         19 . A vehicle control system comprising:
 a controller configured to receive a current commanded speed that a vehicle system is to move, the controller also configured to determine a current moving speed at which the vehicle system is moving and to calculate a reference shaped speed at which one or more of a propulsion system or a brake system of the vehicle system is directed to operate to cause the current moving speed of the vehicle system to approach the current commanded speed,   the reference speed determined by the controller by increasing or decreasing a previous value of the reference shaped speed at a rate that changes based on a difference between a current value of the reference shaped speed and the current commanded speed,   the controller configured to control the one or more of the propulsion system or the brake system to operate to cause the vehicle system to move at the reference shaped speed that is calculated.   
     
     
         20 . The vehicle control system of  claim 19 , wherein the controller is configured to calculate a faster value for the rate when the difference between the current value of the reference shaped speed and the current commanded speed is larger and a slower value when the difference between the current value of the reference shaped speed and the current commanded speed is smaller.