Automatic leveling control system

Abstract

An automatic leveling control system for a machine having a work attachment adapted for leveling as the machine is propelled about a worksite is provided. A single laser receiver is mounted to one of two lift arms of the machine. The laser receiver is configured to receive a laser signal from a laser plane generator and to provide a height signal. A tilt sensor is mounted to a work attachment mounting structure and is configured to sense a tilt angle of the work attachment mounting structure and to provide a tilt angle signal and a lateral tilt signal in dependence on lateral tilt of the machine. A controller is configured for generating a control signal based on the height signal, the tilt angle signal and the lateral tilt signal and for communicating the control signal to the machine to adjust at least one of a height of the lift arms and the tilt angle of the work attachment mounting structure such that a grading edge of the work attachment is maintained at elevation as the machine is propelled about the worksite.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . An automatic leveling control system for a machine having a work attachment adapted for leveling as the machine is propelled about a worksite, the system comprising:
 a. a single laser receiver mounted to one of two lift arms of the machine, the laser receiver being configured to receive a laser signal from a laser plane generator associated with a predetermined level and to provide a height signal in dependence thereupon;   b. a tilt sensor mounted to a work attachment mounting structure, the work attachment mounting structure being pivotally movable mounted to a front end portion of the lift arms and having the work attachment mounted thereto, the tilt sensor being configured to sense a tilt angle of the work attachment mounting structure and to provide a tilt angle signal in dependence thereupon, the tilt sensor further being configured to sense a lateral tilt of the machine and to provide a lateral tilt signal in dependence thereupon;   c. a controller connected to the laser receiver and the tilt sensor, the controller being configured for generating a control signal based on the height signal, the tilt angle signal and the lateral tilt signal and for communicating the control signal to the machine to adjust at least one of a height of the lift arms and the tilt angle of the work attachment mounting structure such that a grading edge of the work attachment is maintained at an elevation substantially corresponding to the predetermined level as the machine is propelled about the worksite.   
     
     
         2 . The system according to  claim 1  wherein the laser receiver is mounted to a front end portion of the lift arm. 
     
     
         3 . The system according to  claim 1  wherein the controller is an automotive programmable logic controller having CAN interfaces connected to a CAN network of the machine. 
     
     
         4 . The system according to  claim 3  wherein the controller is connected to at least a button of a joystick of the machine. 
     
     
         5 . The system according to  claim 3  comprising a human-machine interface connected to the controller. 
     
     
         6 . An automatic leveling control system for a machine having a work attachment adapted for leveling as the machine is propelled about a worksite, the system comprising:
 a. a laser receiver mounted to the machine, the laser receiver being configured to receive a laser signal from a laser plane generator associated with a predetermined level and to provide a height signal in dependence thereupon;   b. an automotive programmable logic controller connected to the laser receiver, the controller being configured for generating a control signal based on the height signal and for communicating the control signal to the machine to adjust the work attachment such that a grading edge thereof is maintained at an elevation substantially corresponding to the predetermined level as the machine is propelled about the worksite.   
     
     
         7 . The system according to  claim 6  wherein the controller is connected to at least a button of a joystick of the machine. 
     
     
         8 . The system according to  claim 6  comprising a human-machine interface connected to the controller. 
     
     
         9 . The system according to  claim 6  wherein the laser receiver is mounted to a lift arm of the machine. 
     
     
         10 . The system according to  claim 9  comprising a tilt sensor mounted to a work attachment mounting structure, the work attachment mounting structure being pivotally movable mounted to a front end portion of the lift arms and having the work attachment mounted thereto, the tilt sensor being configured to sense a tilt angle of the work attachment mounting structure and to provide a tilt angle signal in dependence thereupon, the tilt sensor further being configured to sense a lateral tilt of the machine and to provide a lateral tilt signal in dependence thereupon. 
     
     
         11 . An automatic leveling control method for a machine having a work attachment adapted for leveling as the machine is propelled about a worksite, the method comprising:
 a. using a controller, receiving at least a sensor signal associated with a predetermined level;   b. using the controller, generating a control signal based on the at least a sensor signal and communicating the control signal to at least a hydraulic actuator of the machine to adjust the work attachment such that a grading edge thereof is maintained at an elevation substantially corresponding to the predetermined level as the machine is propelled about the worksite,   
       wherein the control signal is determined such that hydraulic power for adjusting the work attachment is started at a predetermined minimum hydraulic power and is increased according to a predetermined ramp time until a predetermined maximum hydraulic power is reached or the adjustment is completed. 
     
     
         12 . The method according to  claim 11  comprising receiving from a human-machine interface connected to the controller data indicative of the minimum hydraulic power, the maximum hydraulic power, and the ramp time. 
     
     
         13 . The method according to  claim 12  comprising receiving from the human-machine interface first data indicative of the minimum hydraulic power, the maximum hydraulic power, and the ramp time for moving a grading edge of the work attachment in an upward direction and second data indicative of the minimum hydraulic power, the maximum hydraulic power, and the ramp time for moving the grading edge of the work attachment in a downward direction. 
     
     
         14 . The method according to  claim 12  comprising receiving from the human-machine interface:
 a. first data indicative of the minimum hydraulic power, the maximum hydraulic power, and the ramp time for moving lift arms of the machine in an upward direction; 
 b. second data indicative of the minimum hydraulic power, the maximum hydraulic power, and the ramp time for moving the lift arms of the machine in a downward direction; 
 c. third data indicative of the minimum hydraulic power, the maximum hydraulic power, and the ramp time for tilting a grading edge of the work attachment in an upward direction; and, 
 fourth data indicative of the minimum hydraulic power, the maximum hydraulic power, and the ramp time for tilting the grading edge of the work attachment in a downward direction. 
 
     
     
         15 . The method according to  claim 14  comprising:
 a. moving the work attachment to a predetermined tilt angle; 
 b. sensing the predetermined tilt angle; and, 
 c. communicating to the controller data indicative of the predetermined tilt angle. 
 
     
     
         16 . The method according to  claim 15  comprising moving the grading edge of the work attachment to the predetermined level. 
     
     
         17 . The method according to  claim 16  comprising adjusting the work attachment such that the grading edge is maintained at an elevation substantially corresponding to the predetermined level and at the predetermined tilt angle as the machine is propelled about the worksite.