Down-force control in a work machine having articulating arms

Abstract

A work machine, such as an excavator or a backhoe, has a linkage of articulating arms for maneuvering a changeable work tool. Position and motion sensors and force sensors within the linkage provide data for a controller to determine a location of the work tool and down force applied from the linkage onto the work tool during a job. Based on characteristics of the work tool, an acceptable range of down force applied by the linkage may be assigned. If down force reaches an outer bound of the acceptable range during the job, the controller may generate an alert for the operator or adjust action by the work tool to maintain the down force within the acceptable range. Depending on the work tool and job, the down-force control can help improve work quality and guard against tool damage from dry-fire or overload conditions.

What is claimed is: 
     
         1 . A computer-implemented method, comprising:
 receiving, by an electronic controller within a work machine, tool data indicative of characteristics for a work tool attached to a linkage of the work machine, the linkage including a boom pivotally joined to the work machine and a stick pivotally joined to the boom;   receiving force data indicative of an acceptable range for down force delivered by the linkage on the work tool during a job, the down force being a force in a downward direction between the work tool and a work surface;   receiving, by the electronic controller and via an operator interface, one or more signals requesting movement by the work tool during the job;   causing, in response to the one or more signals, action by the work tool as part of the job;   receiving, from one or more sensors within the linkage, sensor data indicative of forces on at least the boom during the action;   calculating, based at least in part on the sensor data and the characteristics for the work tool, the down force on the work tool during the action;   determining that the down force on the work tool during the action is at or outside an outer bound of the acceptable range; and   causing output of an alert via the operator interface.   
     
     
         2 . The computer-implemented method of  claim 1 , further comprising:
 at least in part in response to the alert, adjusting the action by the work tool to change the down force to be within the acceptable range.   
     
     
         3 . The computer-implemented method of  claim 1 , wherein the action of the work tool is movement caused by one or more power sources within the work tool, and wherein the down force is below the acceptable range, the method further comprising:
 causing the one or more power sources to inhibit the movement.   
     
     
         4 . The computer-implemented method of  claim 1 , wherein the characteristics of the work tool include a tool weight and a tool center-of-gravity. 
     
     
         5 . The computer-implemented method of  claim 1 , further comprising:
 receiving, by the electronic controller, linkage data indicative of characteristics for the linkage, the characteristics for the linkage including dimensions, a boom center-of-gravity, and a stick center-of-gravity.   
     
     
         6 . A control system within a work machine, comprising:
 one or more actuators positioned to impart forces on arms of the work machine;   one or more sensors positioned within the arms, the one or more sensors being configured to detect positions of the arms and the forces on the arms;   a memory;   a controller communicatively coupled to the one or more actuators, the one or more sensors, and the memory, the controller configured to:
 receive, from an operator interface within the work machine, one or more manual commands to cause activity by a work tool; 
 receive a boundary value for down force delivered by a linkage on the work tool; 
 cause the activity by the work tool according to the one or more manual commands; 
 receive, from the one or more sensors, sensor data indicative of the forces on the arms during the activity; 
 calculate, at least in part from the sensor data, the down force on the work tool during the activity; 
 determine that the down force on the work tool during the activity is at or beyond the boundary value; and 
 cause output of an alert via the operator interface. 
   
     
     
         7 . The control system of  claim 6 , wherein the boundary value includes a minimum amount of down force on the work tool. 
     
     
         8 . The control system of  claim 7 , wherein the controller is further configured, after causing the output of the alert, to:
 set a timer; and   after expiration of the timer, determine that the down force remains below the minimum amount; and   cause inhibition of the activity of the work tool.   
     
     
         9 . The control system of  claim 7 , wherein the work tool is a hydromechanical work tool and the activity is vibration with respect to a work surface. 
     
     
         10 . The control system of  claim 6 , wherein the boundary value is a range of acceptable down force delivered by the linkage on the work tool. 
     
     
         11 . The control system of  claim 6 , wherein the boundary value includes a maximum amount of down pressure on the work tool, and the activity is a force from the linkage on the work tool in a downward direction. 
     
     
         12 . The control system of  claim 11 , wherein the controller is further configured, after causing output of the alert, to:
 set a timer; and   after expiration of the timer, determine that the down force remains above the maximum amount; and   cause inhibition of the force on the work tool in the downward direction.   
     
     
         13 . A work machine, comprising:
 a linkage including a boom pivotally interconnected with a stick;   sensors, associated with the linkage, configured to detect positions and forces within the boom and the stick;   a work tool coupled to the stick;   an operator interface configured to receive inputs for controlling the work machine and to display outputs relating to operation of the work machine;   an electronic controller communicatively coupled to the sensors and the operator interface, the electronic controller configured to:
 receive, from the operator interface, one or more commands to cause motion by the work tool as part of a job; 
 receive a boundary value for down force delivered by the linkage on the work tool during the job; 
 cause the motion by the work tool according to the one or more commands; 
 receive, from the sensors within the linkage, sensor data indicative of forces on at least the boom and the stick during the motion; 
 calculate, at least in part from the sensor data, the down force on the work tool during the motion; 
 determine that the down force on the work tool during the motion is outside the boundary value; and 
 one of cause output of an alert or inhibit the motion of the work tool. 
   
     
     
         14 . The work machine of  claim 13 , wherein the boundary value is a minimum amount of down force on the work tool. 
     
     
         15 . The work machine of  claim 14 , wherein the electronic controller is further configured, after causing the output of the alert, to:
 set a timer; and   after expiration of the timer, determine that the down force remains below the minimum amount; and   cause the inhibition of the motion of the work tool.   
     
     
         16 . The work machine of  claim 14 , wherein the motion of the work tool is caused by one or more tool actuators within the work tool, the electronic controller being further configured to:
 cause the one or more tool actuators to inhibit the motion.   
     
     
         17 . The work machine of  claim 14 , further comprising one or more actuators, associated with the linkage, configured to move the linkage and the work tool, the one or more actuators being one of hydraulic or electric. 
     
     
         18 . The work machine of  claim 14 , wherein the motion of the work tool is oscillating or rotating with respect to a work surface. 
     
     
         19 . The work machine of  claim 13 , wherein the boundary value is a maximum amount of down force on the work tool, and the motion is a force from the linkage on the work tool in a downward direction. 
     
     
         20 . The work machine of  claim 19 , wherein the electronic controller is further configured, after causing output of the alert, to:
 set a timer; and   after expiration of the timer, determine that the down force remains above the maximum amount; and   cause the inhibition of the force on the work tool in the downward direction.