Machine control system for milling arched roof structures

Abstract

A control system may be provided for a machine having a swivel chair, a positioning member attached to the swivel chair, a wrist attached to the positioning member, and a cutting head. The control system may include at least one actuator capable of extending and swinging the swivel chair. The control system may also include a lift actuator capable of pivoting the positioning member, a gear mechanism capable of rotating the wrist, and a controller in communication with the swivel chair actuator, the lift actuator, and the wrist actuator. The controller may be capable of determining an excavation pass having a trajectory made from sequential vector paths, and directing the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head such that a rotation axis of the cutting head follows the trajectory through each vector path of the excavation pass to form a structure.

What is claimed is: 
     
         1 . A control system for a machine having a swivel chair, a positioning member coupled to the swivel chair, a wrist coupled to the positioning member, and a cutting head, the control system comprising:
 at least one swivel chair actuator configured to extend the swivel chair along an extension axis and to swing the swivel chair about a swing axis that is substantially perpendicular to the extension axis;   a lift actuator configured to pivot the positioning member about a pivot axis;   a gear mechanism configured to rotate the wrist about a wrist axis; and   a controller in communication with the swivel chair actuator, the lift actuator, and the wrist actuator, the controller being configured to:
 determine an excavation pass having a trajectory made from a plurality of sequential vector paths; and 
 direct the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head such that a rotation axis of the cutting head follows the trajectory through each vector path of the excavation pass to form a structure 
   
     
     
         2 . The control system of  claim 1 , wherein:
 the excavation pass is a first excavation pass that forms an arcuate upper portion of a cross-section of the structure; and   the controller is further configured to:
 determine a second excavation pass having a trajectory made from a plurality of sequential vector paths; and 
 direct the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head such that the rotation axis of the cutting head follows the trajectory of the second excavation pass through each vector path of the second excavation pass to form a lower portion of the cross-section of the structure. 
   
     
     
         3 . The control system of  claim 2 , wherein the controller is configured to move the cutting head to follow the trajectory of the second excavation pass and then the trajectory of the first excavation pass in a particular pattern. 
     
     
         4 . The control system of  claim 1 , wherein:
 the structure is a tunnel;   each of the plurality of sequential vector paths includes a start target position and an end target position;   wherein the start target position corresponds to an actual position of the cutting head; and   the controller is configured to determine locations of the end target locations by determining a perimeter of a desired shape of the tunnel, offsetting the perimeter by a radius of the cutting head to extrapolate an inset perimeter, and continuously generating end target locations along the inset perimeter according to a time interval cycle.   
     
     
         5 . The control system of  claim 4 , further including an environment sensor configured to generate signals indicative of locations of features in an environment of the machine, wherein the controller is configured to determine the start and end target locations for each of the plurality of sequential vector paths based further on the signals. 
     
     
         6 . The control system of  claim 5 , wherein the controller is configured to determine the start and end target locations based further on a desired depth of the excavation pass. 
     
     
         7 . The control system of  claim 4 , wherein the perimeter is at least partially defined by an arc of a perfect circle. 
     
     
         8 . The control system of  claim 1 , wherein each of the plurality of vector paths are linear vector paths. 
     
     
         9 . The control system of  claim 1 , further including a position sensor configured to generate signals indicative of at least one of a position of the cutting head or an orientation of the cutting head, wherein the controller is configured to direct the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head based on the signals. 
     
     
         10 . A method for operating a machine having a cutting head, the method comprising:
 determining an excavation pass having a trajectory made from a plurality of sequential vector paths; and   directing a swivel chair actuator of the machine, a lift actuator of the machine, and a wrist actuator of the machine to selectively move the cutting head such that a rotation axis of the cutting head follows the trajectory through each vector path of the excavation pass to form a structure.   
     
     
         11 . The method of  claim 10 , wherein:
 the excavation pass is a first excavation pass that forms an arcuate upper portion of a cross-section of the structure; and   the method further includes
 determining a second excavation pass having a trajectory made from a plurality of sequential vector paths; and 
 directing the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head such that the rotation axis of the cutting head follows the trajectory of the second excavation pass through each vector path of the second excavation pass to form a lower portion of the cross-section of the structure. 
   
     
     
         12 . The method of  claim 11 , wherein directing the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head includes directing the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head to follow the trajectory of the first excavation pass and then the trajectory of the second excavation pass in a particular pattern. 
     
     
         13 . The method of  claim 10 , wherein:
 the structure is a tunnel;   each of the plurality of sequential vector paths includes a start target position and an end target position;   wherein the start target position corresponds to an actual position of the cutting head; and   determining the excavation pass includes determining locations of the end target locations by determining a perimeter of a desired shape of the tunnel, offsetting the perimeter by a radius of the cutting head to extrapolate an inset perimeter, and continuously generating end target locations along the inset perimeter according to a time interval cycle.   
     
     
         14 . The method of  claim 13 , further including sensing locations of features in an environment of the machine, wherein determining locations of the start target position and end target position includes determining locations of the start target position and end target position based on the locations of the features. 
     
     
         15 . The method of  claim 14 , wherein determining locations of the start target position and end target position includes determining locations of the start target position and end target position based further on a desired depth of the excavation pass. 
     
     
         16 . The method of  claim 13 , wherein the perimeter is at least partially defined by an arc of a circle. 
     
     
         17 . The method of  claim 10 , wherein each of the plurality of vector paths are linear vector paths. 
     
     
         18 . The method of  claim 10 , further including sensing at least one of a position and an orientation of the cutting head, wherein directing the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head includes directing the swivel chair actuator, the lift actuator, and the wrist actuator to selectively move the cutting head based on the at least one of the position and the orientation of the cutting head. 
     
     
         19 . A machine, comprising:
 a frame;   a swivel chair pivotally connected to the frame;   a positioning member coupled to the swivel chair;   a wrist coupled to the positioning member;   a cutting head coupled to the wrist;   an extension actuator configured to extend the swivel chair along an extension axis;   a swing actuator configured to swing the swivel chair about a swing axis that is substantially perpendicular to the extension axis;   a lift actuator configured to pivot the positioning member about a pivot axis;   a gear mechanism configured to rotate the wrist about a wrist axis; and   a controller in communication with the extension actuator, the swing actuator, the lift actuator, and the wrist actuator, the controller being configured to:
 determine a first excavation pass having a first trajectory made from a plurality of sequential vector paths that forms an arcuate upper portion of a cross-section of a structure; 
 determine a second excavation pass having a second trajectory made from a plurality of sequential vector paths that forms a lower portion of the cross-section of the structure; and 
 direct the extension actuator, the swing actuator, the lift actuator, and the wrist actuator to selectively move the cutting head such that a rotation axis of the cutting head follows the first and second trajectories through each vector path of the first and second excavation passes to form the structure. 
   
     
     
         20 . The machine of  claim 19 , wherein:
 the structure is a tunnel; and   the controller is configured to move the cutting head to follow the trajectory of the second excavation pass and then the trajectory of the first excavation pass in a particular pattern.