Automatic blade pitch adjustment for dozer
A system and a method detect an initial movement of a work machine having a blade. The pitch of the blade is automatically adjusted such that a cutting edge of the blade is at a cutting angle with respect to the surface to enable initiation of a cut below a track plane by the cutting edge. When the cutting edge is elevated to or above the track plane, the pitch of the blade is automatically adjusted to a carry angle. When the cutting edge rises at least a selected distance above the track plane, the pitch of the blade is automatically adjusted to a shedding angle. When the work machine is cutting, the system and method detect bridging of the work machine and automatically reduce the angle of the blade to counter the bridging effect.
1 . A computer-assisted method of controlling the pitch of a blade of a work machine comprising:
initiating movement of the work machine in a forward direction along a surface to be modified by the blade of the work machine;
responding to the movement of the work machine by automatically changing the pitch of the blade to a first pitch such that a cutting edge of the blade is at a cutting angle with respect to the surface being modified;
lowering the blade to position the cutting edge below an elevation of a track plane to initiate cutting of the surface to be modified;
raising the blade to position the cutting edge at the elevation of the track plane;
responding to the cutting edge rising to the elevation of the track plane by automatically changing the pitch of the blade to a second pitch such that the cutting edge is at a carry angle with respect to the surface being modified;
raising the blade to position the cutting edge above the elevation of the track plane; and
responding to the cutting edge rising above the elevation of the track plane by automatically changing the pitch of the blade to a third pitch such that the cutting edge is at a shedding angle with respect to the surface being modified.
2 . The method as defined in claim 1 wherein the carry angle is less than the cutting angle and the shedding angle is greater than the cutting angle.
3 . The method as defined in claim 1 wherein:
the blade is supported at a pivot location of a support structure extending from the work machine and wherein:
the blade has an upper portion and a lower portion, the cutting edge positioned at the lower portion, the upper portion at a first upper portion position and the lower portion at a first lower portion position when the blade is at the first pitch;
changing the pitch to the second pitch moves the upper portion of the blade to a second upper portion position toward the front of the work machine and positions the lower portion of the blade to a second lower portion position away from the front of the work machine;
changing the pitch to the third pitch moves the upper portion of the blade to a third upper portion position away from the front of the work machine and positions the lower portion of the blade to a third lower portion position toward the front of the work machine; and
changing the pitch to the first pitch moves the upper portion of the blade to the first upper portion position between the second upper portion position and the third upper portion position, and moves the lower portion of the blade to the first lower portion position between the second lower portion position and the third lower portion position.
4 . The method as defined in claim 1 further comprising:
detecting bridging of the work machine wherein at least a portion of at least one ground engaging unit of the work machine is elevated above the surface being modified; and
automatically changing the pitch of the blade to increase the angle of the cutting edge and to thereby counter the bridging.
5 . The method as defined in claim 1 wherein the cutting edge of the blade is removably attached to the lower portion of the blade.
6 . A control system for operating a work machine comprising a plurality of ground-engaging units, which support a machine frame and which are driven to cause the work machine to travel across a ground surface, the work machine further comprising a blade supported by a support structure extending from the machine frame, the blade having an upper portion and a lower portion, the lower portion supporting a cutting edge configured to sculpt the ground surface along a track plane, wherein the control system comprises:
a controller configured to:
receive signals from the work machine indicating the movement of the work machine and signals indicating changes in elevation of the blade;
generate signals to control the work machine and to control the pitch of the blade;
respond to forward movement of the work machine by adjusting the pitch of the blade to a first pitch such that the cutting edge is at a cutting angle with respect to the surface being sculpted;
respond to the cutting edge being lowered below the track plane and then being raised to the elevation of the track plane by adjusting the pitch of the blade to a second pitch such that the cutting edge is at a carry angle with respect to the surface to being sculpted; and
respond to the cutting edge rising above the track plane by adjusting the pitch of the blade to a third pitch such that the cutting edge is at a shedding angle with respect to the surface being sculpted.
7 . The control system as defined in claim 6 wherein the carry angle is less than the cutting angle and the shedding angle is greater than the cutting angle.
8 . The control system as defined in claim 6 wherein the controller is configured to:
adjust the pitch of the blade to the second pitch by moving the upper portion of the blade to a rearward upper portion position toward the front of the work machine and by moving the lower portion of the blade to a forward lower portion position away from the front of the work machine;
adjust the pitch of the blade to the third pitch by moving the upper portion of the blade to a forward upper portion position away from the front of the work machine and by moving the lower portion of the blade to a rearward lower portion position toward the front of the work machine; and
adjust the pitch of the blade to the third pitch by moving the upper portion of the blade to a upper portion position between the rearward upper portion position and the forward upper portion position and by moving the lower portion of the blade to a lower portion position between the forward lower portion position and the rearward lower portion position.
9 . The control system as defined in claim 6 wherein the controller is further configured to:
detect bridging of the work machine wherein at least a portion of at least one of the ground engaging units of the work machine is elevated above the surface being modified; and
automatically change the pitch of the blade to increase the angle of the cutting edge and thereby counter the bridging.
10 . The control system as defined in claim 6 wherein the cutting edge of the blade is removably attached to the lower portion of the blade.
11 . A method of sculpting a surface along a track plane using a cutting edge of a blade of a work machine, wherein the blade is supported by a support structure extending from the work machine, wherein the blade has an adjustable pitch with respect to the support structure that enables the cutting edge of the blade to be adjustable to a selected angle with respect to the surface, the method comprising:
positioning the work machine to position the cutting edge of the blade proximate to a portion of the surface;
initiating forward movement of the work machine along the track plane;
responding to the forward movement of the work machine by automatically adjusting the pitch of the cutting edge of the blade to a cutting angle with respect to the surface and lowering the cutting edge into the surface;
raising the blade to position the cutting edge at an elevation of the track plane;
responding to the cutting edge rising to the elevation of the track plane by automatically adjusting the cutting edge of the blade to a carry angle with respect to the surface;
raising the cutting edge to an elevation above the elevation of the track plane; and
responding to the cutting edge rising about the track plane by automatically adjusting the cutting edge of the blade to a shedding angle.
12 . The method as defined in claim 11 wherein the carry angle is less than the cutting angle and the shedding angle is greater than the cutting angle.
13 . The method as defined in claim 11 further compromising:
detecting bridging of the work machine wherein at least a portion of at least one ground engaging unit of the work machine is elevated above the surface being modified; and
automatically pivoting the blade to increase the angle of the cutting edge and thereby counter the bridging.
14 . The method as defined in claim 11 wherein the cutting edge of the blade is removably attached to the lower portion of the blade.