Propulsion control system and method for railway maintenance vehicles

Abstract

A propulsion control system is provided for controlling a hydraulic drive system of a railway maintenance vehicle. An axle monitoring module receives and monitors a first signal from a first rotation sensor, and a second signal from a second rotation sensor, the first and second signals associated with first and second axles of the vehicle, respectively. A speed comparison module calculates a delta value representing a difference between the first and second signals, and generates a speed control signal based on the difference. A speed control module receives the speed control signal, and generates a power signal for controlling an amount of power applied to at least one of the first and second axles based on the speed control signal. An actuation control module receives the power signal, and performs a power allocation function for controlling a speed or power of the hydraulic drive system.

What is claimed is: 
     
         1 . A propulsion control system for controlling a hydraulic drive system of a railway maintenance vehicle, comprising:
 an axle monitoring module configured for receiving and monitoring a first signal received from a first rotation sensor, and a second signal received from a second rotation sensor, the first signal being associated with a first axle of the vehicle, and the second signal being associated with a second axle of the vehicle;   a speed comparison module configured for calculating a delta value representing a difference between the first and second signals by comparing values of the first and second signals, and generating a speed control signal based on the comparison;   a speed control module configured for receiving the speed control signal, and generating a power signal for controlling an amount of power applied to at least one of the first and second axles based on the speed control signal; and   an actuation control module configured for receiving the power signal, and performing a power allocation function for controlling a speed or power of the hydraulic drive system that controls at least one of the first and second axles based on the power signal.   
     
     
         2 . The propulsion control system of  claim 1 , wherein each of the first and second rotation sensors detects a rotational speed of an associated axle, and wherein the axle monitoring module monitors the first and second signals for at least one of the first and second axles, and corresponding wheels of the vehicle. 
     
     
         3 . The propulsion control system of  claim 1 , further comprising a database configured for storing relevant speed information on the first and second axles and for retrieving the information from the database. 
     
     
         4 . The propulsion control system of  claim 3 , further comprising an interface module configured for controlling an interface between the first and second rotation sensors, the database, associated modules, and related system devices, services, and applications. 
     
     
         5 . The propulsion control system of  claim 4 , wherein the axle monitoring module receives the first and second signals from the corresponding rotation sensors via the interface module, and transmits the first and second signals to the speed comparison module. 
     
     
         6 . The propulsion control system of  claim 1 , wherein the speed comparison module performs an analysis of the first and second signals for performing the power allocation function on a motor of a hydraulic drive system. 
     
     
         7 . A method for controlling a hydraulic drive system of a railway maintenance vehicle, comprising:
 receiving and monitoring a first signal received from a first rotation sensor, and a second signal received from a second rotation sensor, the first signal being associated with a first axle of the vehicle, and the second signal being associated with a second axle of the vehicle;   calculating a delta value representing a difference between the first and second signals by comparing values of the first and second signals, and generating a speed control signal based on the comparison;   receiving the speed control signal, and generating a power signal for controlling an amount of power applied to at least one of the first and second axles based on the speed control signal; and   receiving the power signal, and performing a power allocation function for controlling a speed or power of the hydraulic drive system that controls at least one of the first and second axles based on the power signal.   
     
     
         8 . The method of  claim 7 , wherein the delta value representing the difference between the first and second signals is an absolute value defined as provided by the following expression:
   ΔRPM=|RPM1−RPM2|
   where RPM1 denotes the first signal and RPM2 denotes the second signal, and further comprising determining which axle is slipping based on the delta value.   
     
     
         9 . The method of  claim 7 , wherein when the delta value is greater than a predetermined threshold value, the speed control signal is generated based on the first and second signals, and the speed control signal is defined as provided by the following expression:
   CTL= f {RPM1,RPM2}   where CTL denotes the speed control signal, RPM1 denotes the first signal and RPM2 denotes the second signal.   
     
     
         10 . The method of  claim 7 , wherein when a value of the first signal is greater than a value of the second signal, the speed control signal is generated based on the first and second signals. 
     
     
         11 . The method of  claim 7 , further comprising reducing or temporarily cutting power to a motor of the hydraulic drive system for controlling at least one of the first and second axles by allocating less power to the motor than a previous power level based on the power signal. 
     
     
         12 . The method of  claim 11 , further comprising determining whether the motor is operated at zero displacement, which generally refers to a condition that the motor is free-wheeling and provides zero torque for moving the vehicle. 
     
     
         13 . The method of  claim 12 , further comprising gradually increasing the power to the motor based on at least one of the speed control signal and a status of the motor when the motor is at zero or minimum displacement. 
     
     
         14 . The method of  claim 11 , further comprising gradually increasing the power applied to the motor using a hydraulic drive system based on the power signal. 
     
     
         15 . The method of  claim 7 , further comprising generating a first auxiliary power signal for applying or delivering pulsing power to at least one of the first and second axles. 
     
     
         16 . The method of  claim 7 , further comprising generating a second auxiliary power signal for applying gradual or pulsing power to corresponding brakes of at least one of the first and second axles. 
     
     
         17 . The method of  claim 7 , further comprising comparing a value of the first signal with a predetermined rotation value for generating the speed control signal based on the comparison. 
     
     
         18 . The method of  claim 17 , further comprising maintaining a power level of a motor of the hydraulic drive system based on the power signal when the value of the first signal is greater than or equal to the predetermined rotation value, or within the predetermined percentage value of the second signal. 
     
     
         19 . The method of  claim 7 , further comprising comparing a value of the first signal with a value of the second signal for determining whether the value of the first signal is within a predetermined percentage value of the second signal. 
     
     
         20 . A propulsion control system for controlling a hydraulic drive system of a railway maintenance vehicle, comprising:
 an axle monitoring module configured for receiving and monitoring a first signal received from a first rotation sensor, and a second signal received from a second rotation sensor, the first signal being associated with a first axle of the vehicle, and the second signal being associated with a second axle of the vehicle;   a speed comparison module configured for comparing an actual current speed of the vehicle and at least one of the first and second signals, and generating a speed control signal based on the comparison when a brake of the vehicle is applied;   a speed control module configured for receiving the speed control signal, and generating a power signal for controlling an amount of power applied to at least one of the first and second axles based on the speed control signal; and   an actuation control module configured for receiving the power signal, and performing a power allocation function for controlling a speed or power of the hydraulic drive system that controls at least one of the first and second axles based on the power signal, and selectively initiating a dynamic braking based on the actual current speed of the vehicle.