Method and Device for Monitoring and Controlling a Hydraulic Actuated Process

Abstract

A method and system for monitoring and controlling a hydraulic pump condition. More specifically, the invention relates to a method and device for monitoring and controlling a hydraulic actuated process indirectly by monitoring and controlling an electric motor driving a positive displacement hydraulic pump. This invention also relates to a precision hydraulic energy delivery system. Direct coupling of the pump to a primary mover (motor) and related motor control allows for complete motion control of a hydraulically driven machine without the use of any downstream devices. By employing motion control algorithms in the motor control, the hydraulic output at the pump head is controlled in a feed forward method.

1 . A method for monitoring and controlling a hydraulic actuated process, comprising the steps of:
 monitoring and controlling an electric motor driving a positive displacement hydraulic pump driving said hydraulic actuated process, said monitoring and controlling being carried out by utilizing an algorithm programmed into the electric motor drive control that systematically measures and corrects for any combination of or all three physical parameters of the motor, pump and hydraulic fluid, thereby optimizing an applied torque and resultant pump pressure, and   wherein said three physical parameters are windage torque, viscous torque and coulomb torque, respectively.   
   
   
       2 . The method according to  claim 1 , wherein a plurality of drives, motors and pumps are electronically line-shafted together providing precise and stable control of pressure and flow being fed to a common output header regardless of individual pump characteristics or fluid condition variations. 
   
   
       3 . The method according to  claim 1 , wherein a precise measurement and control of press-ram position, and/or ram velocity is achieved. 
   
   
       4 . The method according to  claim 1 , wherein said method monitors and/or controls hydraulic pressures created by the pump, which after mathematical correction for line losses at various flow rates, mimics load at the press ram. 
   
   
       5 . The method of  claim 1 , wherein the algorithm includes a subroutine for eliminating a pressure spike; wherein any excess hydraulic output is used to generate electrical energy when a pressure spike occurs; the electrical energy being stored in an energy storage means. 
   
   
       6 . The method of  claim 1 , wherein the algorithm includes a subroutine for eliminating a pump pressure droop; wherein an input signal overrides the existing hydraulic output settings when a pressure droop occurs. 
   
   
       7 . The method of  claim 1 , wherein said drive motor is used both for delivering energy and for reclaiming energy from the hydraulic output. 
   
   
       8 . The method of  claim 1 , wherein the algorithm includes a subroutine for measuring pump shaft torque output and translating the measured torque output into a pressure delivered signal. 
   
   
       9 . The method of  claim 1 , wherein the algorithm includes a subroutine for maintaining a constant horsepower from the drive motor, thereby limiting hydraulic output to the application similarly. 
   
   
       10 . The method of  claim 1 , further comprising means for storing electrical energy including reclaimed energy from regeneration, and for providing for the requirements of high energy applications typically requiring a hydraulic accumulator. 
   
   
       11 . The method of  claim 1 , wherein the algorithm includes a subroutine such that a volumetric pulse correlated with the hydraulic output is used to position the pump cylinders. 
   
   
       12 . The method of  claim 1 , wherein the algorithm includes a subroutine for detecting a pump leakage rate and outputting an alarm when a predetermined leakage limit is exceeded. 
   
   
       13 . The method of  claim 1 , wherein the algorithm includes a subroutine for assessing a pump output level and applying a profile of torque vs. velocity corresponding to the assessed output level. 
   
   
       14 . A hydraulic pump system comprising:
 a hydraulic pump;   a drive motor directly coupled to said pump; and   a motor control coupled to said pump for controlling said drive motor; said motor control employing a motion control algorithm to control a hydraulic output of the pump, wherein said algorithm measures and corrects for any combination of or all three physical parameters of the motor, pump and hydraulic fluid, thereby optimizing an applied torque and resultant pump pressure, and   wherein said three physical parameters are windage torque, viscous torque and coulomb torque and application items REDUX V and REDUX P, respectively.   
   
   
       15 . The system according to  claim 14 , wherein a plurality of drives, motors and pumps are electronically line-shafted together providing precise and stable control of pressure and flow being fed to a common output header regardless of individual pump characteristics or fluid condition variations. 
   
   
       16 . The system according to  claim 14 , wherein a precise measurement and control of press-ram position, and/or ram velocity is achieved. 
   
   
       17 . The system according to  claim 14 , wherein said system monitors and/or controls hydraulic pressures created by the pump, which after mathematical correction for line losses at various flow rates, mimics load at the press ram. 
   
   
       18 . The system of  claim 14 , wherein the algorithm includes a subroutine for eliminating a pressure spike; wherein any excess hydraulic output is used to generate electrical energy when a pressure spike occurs; the electrical energy being stored in an energy storage means. 
   
   
       19 . The system of  claim 14 , wherein the algorithm includes a subroutine for eliminating a pump pressure droop; wherein an input signal overrides the existing hydraulic output settings when a pressure droop occurs. 
   
   
       20 . The system of  claim 14 , wherein said drive motor is used both for delivering energy and for reclaiming energy from the hydraulic output. 
   
   
       21 . The system of  claim 14 , wherein the algorithm includes a subroutine for measuring pump shaft torque output and translating the measured torque output into a pressure delivered signal. 
   
   
       22 . The system of  claim 14 , wherein the algorithm includes a subroutine for maintaining a constant horsepower from the drive motor, thereby limiting hydraulic output to the application similarly. 
   
   
       23 . The system of  claim 14 , further comprising means for storing electrical energy including reclaimed energy from regeneration, and for providing for the requirements of high energy applications typically requiring a hydraulic accumulator. 
   
   
       24 . The system of  claim 14 , wherein the algorithm includes a subroutine such that a volumetric pulse correlated with the hydraulic output is used to position the pump cylinders. 
   
   
       25 . The system of  claim 14 , wherein the algorithm includes a subroutine for detecting a pump leakage rate and outputting an alarm when a predetermined leakage limit is exceeded. 
   
   
       26 . The system of  claim 14 , wherein the algorithm includes a subroutine for assessing a pump output level and applying a profile of torque vs. velocity corresponding to the assessed output level.