Lift Arm and Coupler Control System

Abstract

A control system for a loader having a frame, a lift arm assembly, a coupler, and an operator interface is provided. The control system may include a lift arm position sensor coupled to the lift arm assembly and configured to measure a lift arm position, an inclinometer disposed on the coupler configured to measure a coupler angle, and a controller in electrical communication with each of the lift arm position sensor, the inclinometer and the operator interface. The controller may be configured to receive a baseline command from the operator interface for operating one or more of the lift arm assembly and the coupler, monitor the lift arm position and the coupler angle, and generate at least one command for operating one or more of the lift arm assembly and the coupler based on one or more of the baseline command, the lift arm position and the coupler angle.

What is claimed is: 
     
         1 . A control system for a loader having a frame, a lift arm assembly, a coupler, and an operator interface, the control system comprising:
 a lift arm position sensor coupled to the lift arm assembly and configured to measure a lift arm position;   an inclinometer disposed on the coupler configured to measure a coupler angle; and   a controller in electrical communication with each of the lift arm position sensor, the inclinometer and the operator interface, the controller being configured to receive a baseline command from the operator interface for operating one or more of the lift arm assembly and the coupler, monitor the lift arm position and the coupler angle, and generate at least one command for operating one or more of the lift arm assembly and the coupler based on one or more of the baseline command, the lift arm position and the coupler angle.   
     
     
         2 . The control system of  claim 1 , wherein the lift arm position sensor includes a rotary position sensor configured to measure the lift arm position based on an angular displacement of the lift arm assembly. 
     
     
         3 . The control system of  claim 1 , wherein the lift arm position sensor includes a linear position sensor configured to measure the lift arm position based on a linear displacement of the lift arm assembly. 
     
     
         4 . The control system of  claim 1 , wherein the inclinometer is configured to measure the coupler angle as an angle of the coupler relative to gravity. 
     
     
         5 . The control system of  claim 1 , wherein the controller is configured to generate the at least one command to include one or more of a lift command for controlling the lift arm assembly and a tilt command for controlling the coupler. 
     
     
         6 . The control system of  claim 5 , wherein the controller is configured to communicate the lift command to a lift arm actuator operatively coupled to the lift arm assembly, and communicate the tilt command to a coupler actuator operatively coupled to the coupler. 
     
     
         7 . The control system of  claim 1 , wherein the controller is configured to generate an open loop command based on at least the baseline command and the lift arm position, and generate a closed loop command based on at least the coupler angle. 
     
     
         8 . The control system of  claim 7 , wherein the controller is configured to monitor a lift arm speed derived from a rate of change in the lift arm position, the controller generating the open loop command based on at least the baseline command and one or more of the lift arm position and the lift arm speed. 
     
     
         9 . The control system of  claim 7 , wherein the controller is configured to generate the open loop command and the closed loop command such that one or more of the lift arm assembly and the coupler is operated in accordance with one or more of an automatic leveling routine, a lift arm snubbing routine, and a return-to-dig routine. 
     
     
         10 . A machine, comprising:
 a lift arm assembly;   a lift arm position sensor coupled to the lift arm assembly and configured to measure a lift arm position; and   a controller in electrical communication with the lift arm position sensor, the controller being configured to receive a baseline command corresponding to operator input, monitor the lift arm position, and generate at least one command for operating the lift arm assembly based on the baseline command and the lift arm position.   
     
     
         11 . The machine of  claim 10 , wherein the lift arm position sensor includes a rotary position sensor configured to measure the lift arm position based on an angular displacement of the lift arm assembly relative to the machine. 
     
     
         12 . The machine of  claim 10 , wherein the lift arm position sensor includes a linear position sensor configured to measure the lift arm position based on a linear displacement of the lift arm assembly relative to the machine. 
     
     
         13 . The machine of  claim 10 , wherein the controller is configured to generate a lift command for controlling a lift arm actuator in order to operate the lift arm assembly, the controller being configured to monitor a lift arm speed derived from a rate of change in the lift arm position, and generate the lift command based on the baseline command and one or more of the lift arm position and the lift arm speed. 
     
     
         14 . The machine of  claim 10 , further comprising a coupler pivotally coupled to the lift arm assembly, and an inclinometer coupled to the coupler configured to measure a coupler angle relative to gravity, the controller being configured to monitor the coupler angle and generate the at least one command for operating one or more of the lift arm assembly and the coupler based on the baseline command, the lift arm position and the coupler angle. 
     
     
         15 . The machine of  claim 14 , wherein the controller is configured to generate an open loop command based on at least the baseline command and the lift arm position, and generate a closed loop command based on at least the coupler angle. 
     
     
         16 . A loader, comprising:
 a frame;   a lift arm assembly movably coupled to the frame;   a coupler pivotally coupled to the lift arm assembly;   an operator interface configured to generate a baseline command for operating one or more of the lift arm assembly and the coupler in response to operator input;   a lift arm position sensor coupled to the lift arm assembly and configured to measure a lift arm position;   an inclinometer coupled to the coupler configured to measure a coupler angle; and   a controller in electrical communication with each of at least the lift arm position sensor, the inclinometer and the operator interface, the controller being configured to receive the baseline command from the operator interface, monitor the lift arm position and the coupler angle, and generate at least one command for operating one or more of the lift arm assembly and the coupler based on one or more of the baseline command, the lift arm position and the coupler angle.   
     
     
         17 . The loader of  claim 16 , wherein the inclinometer is configured to measure the coupler angle as an angle of the coupler relative to gravity, and the lift arm position sensor employs one of a rotary position sensor and a linear position sensor, the rotary position sensor being configured to measure the lift arm position based on an angular displacement of the lift arm assembly, and the linear position sensor being configured to measure the lift arm position based on a linear displacement of the lift arm assembly. 
     
     
         18 . The loader of  claim 16 , wherein the controller is configured to generate an open loop command based on at least the baseline command and the lift arm position, and generate a closed loop command based on at least the coupler angle. 
     
     
         19 . The loader of  claim 18 , further comprising a lift arm actuator operatively coupled to the lift arm assembly and a coupler actuator operatively coupled to the coupler, the controller being configured to generate the open loop command and the closed loop command to include one or more of a lift command for controlling the lift arm actuator and a tilt command for controlling the coupler actuator. 
     
     
         20 . The loader of  claim 19 , wherein the controller is configured to derive one or more of a lift arm speed and an estimated payload weight based on one or more of the baseline command, the lift arm position, the coupler angle, a lift pressure associated with the lift arm assembly, and a tilt pressure associated with the coupler actuator, the controller being configured to generate the open loop command and the closed loop command in accordance with one or more of an automatic leveling routine, a lift arm snubbing routine, and a return-to-dig routine.