Hydraulic system having diagnostic mode of operation

Abstract

A hydraulic system is disclosed for use with. a machine. The hydraulic system may have an actuator, a valve associated with the actuator, at least one sensor configured to generate signals indicative of performance parameters of the hydraulic system, and a controller. The controller may be configured to determine at least one of a diagnostic movement and position of at least one of the fluid actuator and valve required to perform a health cheek, and to correlate the signals generated only during completion of the diagnostic movement or only when the at least one of the fluid actuator and valve are in the diagnostic position to values of the performance parameters. The controller may also be configured to make a comparison of the values of the performance parameters to expected values, and to determine a health of the hydraulic system based on the comparison.

What is claimed is: 
     
         1 . A hydraulic system, comprising:
 a fluid actuator;   a valve associated with the fluid actuator;   at least one sensor configured to generate a signal indicative of a performance parameter of the hydraulic system; and   a controller in communication with the at least one sensor and configured to:
 determine at least one of a diagnostic movement and a diagnostic position of at least one of the fluid actuator and the valve required to perform a health check of the hydraulic system; 
 correlate the signal generated only during completion of the diagnostic movement or only when the at least one of the fluid actuator and the valve are in the diagnostic position to a value of the performance parameter; 
 make a comparison of the value of the performance parameter to an expected value; and 
 determine a health of the hydraulic system based on the comparison. 
   
     
     
         2 . The hydraulic system of  claim 1 , wherein the at least one sensor is one of a pressure sensor, a position sensor, a displacement sensor, and a speed sensor. 
     
     
         3 . The hydraulic system of  claim 1 , wherein the at least one sensor includes at least a first sensor located to sense a pressure inside a chamber of the fluid actuator. 
     
     
         4 . The hydraulic system of  claim 3 , wherein the at least one sensor includes at least a second sensor configured to sense a pressure differential across the valve. 
     
     
         5 . The hydraulic system of  claim 4 , further including a pump configured to direct pressurized fluid to the valve, wherein the at least one sensor includes at least a third sensor configured to sense a pressure differential across the pump. 
     
     
         6 . The hydraulic system of  claim 1 , wherein the controller is configured to adjust a result of the comparison for an age of the hydraulic system. 
     
     
         7 . The hydraulic system of  claim 1 , wherein the controller is configured to determine the at least one of the diagnostic movement and the diagnostic position based on a suspected malfunction of the hydraulic system. 
     
     
         8 . The hydraulic system of  claim 1 , wherein the controller is manually triggered to perform the health check of the hydraulic system. 
     
     
         9 . The hydraulic system of  claim 8 , wherein the controller is configured to instruct an operator to cause the at least one of the fluid actuator and the valve to perform the diagnostic movement or to achieve the diagnostic position. 
     
     
         10 . The hydraulic system of  claim 9 , wherein the controller is further configured to selectively recommend one of three possible corrective actions based on the health of the hydraulic system. 
     
     
         11 . The hydraulic system of  claim 9 , wherein the three possible corrective actions include:
 a first level action, wherein the operator is instructed to schedule a particular maintenance activity to occur at a next regular service interval;   a second level action, wherein the operator is instructed to perform the particular maintenance activity at a next convenient time; and   a third level action, wherein the operator is instructed to immediately shut down the hydraulic system and perform the particular maintenance activity.   
     
     
         12 . The hydraulic system of  claim 1 , wherein the controller is automatically triggered to perform the health check of the hydraulic system based on a sensed performance parameter of the hydraulic system. 
     
     
         13 . The hydraulic system of  claim 12 , wherein the controller is configured to automatically cause the at least one of the fluid actuator and the valve to perform the diagnostic movement or to achieve the diagnostic position. 
     
     
         14 . The hydraulic system of  claim 13 , wherein the controller is further configured to automatically implement one of three possible corrective actions based on the health of the hydraulic system. 
     
     
         15 . The hydraulic system of  claim 9 , wherein the three possible corrective actions include:
 a first level action, wherein the controller automatically schedules a particular maintenance activity to occur at a next regular service interval;   a second level action, Wherein the controller automatically schedules the particular maintenance activity to occur at a next convenient time; and   a third level action, wherein the controller immediately shuts down the hydraulic system and generates a request for the particular maintenance activity to be performed before restart of the hydraulic system.   
     
     
         16 . The hydraulic system of  claim 1 , wherein the controller is configured to continuously perform the health check of the hydraulic system whenever the at least one of the fluid actuator and the valve are in performance of the diagnostic movement or are in the diagnostic position. 
     
     
         17 . A method of determining a health of a hydraulic system having a fluid actuator and a valve associated with the fluid actuator, the method comprising:
 generating a signal indicative of a performance parameter of the hydraulic system;   determining at least one of a diagnostic movement and a diagnostic position of at least one of the fluid actuator and the valve required for diagnosing the health of the hydraulic system;   correlating the signal generated only during completion of the diagnostic movement or only when the at least one of the fluid actuator and the valve are in the diagnostic position to a value of the performance parameter;   making a comparison of the value of the performance parameter to an expected value; and   determining the health of the hydraulic system based on the comparison.   
     
     
         18 . The method of  claim 17 , further including adjusting the comparison based on an age of the hydraulic system. 
     
     
         19 . The method of  claim 17 , wherein determining the at least one of the diagnostic movement and the diagnostic position of the at least one of the fluid actuator and the valve includes determining the at least one of the diagnostic movement and the diagnostic position of the at least one of the fluid actuator and the valve based on a suspected malfunction of the hydraulic system. 
     
     
         20 . A machine, comprising:
 a frame;   a power source mounted to the frame;   a linkage arrangement;   a fluid actuator configured to move the linkage arrangement;   a pump;   a sump;   a valve disposed between the fluid actuator, the pump, and the sump;   a plurality of sensors configured to generate signals indicative of performance parameters of the machine; and   a controller in communication with the plurality of sensors and configured to:
 receive input indicative of a suspected hydraulic component malfunction; 
 determine at least one of a diagnostic movement and a diagnostic position of at least one of the fluid actuator and the valve required to performe a health check of the machine based on the suspected hydraulic component malfunction; 
 correlate the signals generated only during completion of the diagnostic movement or only when the at least one of the fluid actuator and the valve are in the diagnostic position to values of the performance parameters; 
 determine an age of the machine; 
 make an age-adjusted comparison of the values of the performance parameters to expected values; and 
 determine a health of the machine based on the age-adjusted comparison.