Torque control of hydraulic work machines

Abstract

A torque control apparatus of a work machine is constructed to control motion of a work tool relative to a swing body of the work machine through a hydraulic system thereof. The control apparatus includes a pose sensor constructed to generate orientation data indicating an orientation of the work machine relative to the undercarriage thereof. A hydraulic flow control component is constructed to generate torque magnitude data corresponding to the orientation data. A machine control component is constructed to generate hydraulic flow rate change data corresponding to the torque magnitude data. A variable flow rate pump is constructed to impel a flow rate in the hydraulic system corresponding to the hydraulic flow rate change rate data.

What is claimed is: 
     
         1 . A torque control apparatus of a work machine constructed to control motion of a work tool relative to a swing body of the work machine through a hydraulic system thereof, the control apparatus comprising:
 a pose sensor constructed to generate orientation data indicating an orientation of the work machine relative to the swing body thereof;   a hydraulic flow control component constructed to generate torque magnitude data corresponding to the orientation data;   a machine control component constructed to generate hydraulic flow rate change data corresponding to the torque magnitude data; and   a variable flow rate pump constructed to impel a flow rate in the hydraulic system corresponding to the hydraulic flow rate change data.   
     
     
         2 . The torque control apparatus of  claim 1 , wherein the hydraulic flow control component is further constructed to select between torque magnitudes corresponding to respective orientations of the work machine. 
     
     
         3 . The torque control apparatus of  claim 2 , wherein the hydraulic flow control component reduces the torque magnitude responsive to the orientation of the work machine meeting a threshold condition. 
     
     
         4 . The torque control apparatus of  claim 3 , wherein the threshold condition is an angle from zenith of the swing body along roll or pitch axes. 
     
     
         5 . The torque control apparatus of  claim 1 , wherein the variable flow rate pump is a variable displacement pump. 
     
     
         6 . The torque control apparatus of  claim 5 , wherein the hydraulic flow control component controls the pump upstroke/destroke of the variable displacement pump. 
     
     
         7 . The torque control apparatus of  claim 1 , wherein the flow rate is controlled by a proportional integral control process. 
     
     
         8 . An excavator constructed to perform earth moving job tasks with a work tool positioned by a hydraulic system installed on the excavator, the excavator comprising:
 a pose sensor constructed to generate orientation data indicating an orientation of the excavator relative to a swing body thereof;   a hydraulic flow control component constructed to generate torque magnitude data corresponding to the orientation data;   a machine control component constructed to generate pump upstroke/destroke rate data corresponding to the torque magnitude data; and   a variable flow rate pump constructed to impel a flow rate change in the hydraulic system corresponding to the pump upstroke/destroke rate data.   
     
     
         9 . The excavator of  claim 8 , wherein the hydraulic flow control component is further constructed to select between torque magnitudes corresponding to respective orientations of the work machine. 
     
     
         10 . The excavator of  claim 9 , wherein the hydraulic flow control component reduces the torque magnitude responsive to the orientation of the work machine meeting a threshold condition. 
     
     
         11 . The excavator of  claim 10 , wherein the threshold condition is an angle from zenith of the swing body along roll or pitch axes. 
     
     
         12 . The excavator of  claim 8 , wherein the variable flow rate pump is a variable displacement pump. 
     
     
         13 . The excavator of  claim 12 , wherein the machine control component controls the pump upstroke/destroke of the variable displacement pump. 
     
     
         14 . The excavator of  claim 8 , wherein the flow rate change is controlled by a proportional integral control process. 
     
     
         15 . A torque control method of a work machine constructed to control motion of a work tool relative to a swing body of the work machine through a hydraulic system thereof, the method comprising:
 generating orientation data indicating an orientation of the work machine relative to the swing body thereof;   generating torque magnitude data corresponding to the orientation data;   generating pump upstroke/destroke data corresponding to the torque magnitude data; and   impelling, by a variable displacement pump, a flow rate in the hydraulic system corresponding to the pump upstroke/destroke data.   
     
     
         16 . The torque control method of  claim 15 , further comprising selecting between torque magnitudes corresponding to respective orientations of the work machine. 
     
     
         17 . The torque control method of  claim 16 , further comprising reducing the torque magnitude responsive to the orientation of the work machine meeting a threshold condition. 
     
     
         18 . The torque control method of  claim 17 , wherein the threshold condition is an angle from zenith of the swing body along roll or pitch axes. 
     
     
         19 . The torque control method of  claim 15 , further comprising controlling the upstroke/destroke data in accordance with a proportional integral control process. 
     
     
         20 . The torque control method of  claim 15 , further comprising controlling the pump upstroke/destroke of the variable displacement pump.