A mobile work machine includes a first grade control system that receives a an external reference position signal from a geographic positioning system, and generates blade control signals to control an orientation of a blade in grading a worksite. The mobile work machine also includes a second grade control system that uses blade mainfall and cross slope as well as chassis (or mainframe) mainfall and cross slope to control the orientation of the blade relative to the frame of the work machine to create a planar grade of a desired mainfall and cross slope. When functionality of the first grade control system is interrupted, the mobile work machine automatically switches to using the second grade control system to perform the grading operation, until the interruption to the functionality of the first grade control system is restored.

A dozer blade attachment control system for a work machine comprises a dozer blade attachment coupled to the attachment coupler, a hydraulic circuit, and an electronic controller. The hydraulic circuit comprises a hydraulic pump, a diverter valve operable in a first position and second position, and a pressure compensated directional control valve. The electronic controller is communicatively coupled to the hydraulic circuit. The electronic circuit may modify the hydraulic circuit to one or more of a first configuration with the diverter valve in the first position for tilt, a second configuration with the diverter valve in the second position for angling, and a third configuration with the diverter valve in the second position and the pressure compensated directional control valve creating a shuttle flow path from a higher and a lower side of the hydraulic circuit for simultaneously tilting and angling.

Methods and systems are described for estimating yaw of an implement relative to a machine. The yaw is estimated using gyro signals. The gyro signals may be provided by gyro sensors such as IMUs that are coupled to the implement and machine.

A work vehicle comprising a frame supported by a ground engaging device. A boom assembly is coupled to the frame. A boom cylinder is coupled to the frame and the boom assembly. An attachment coupler is coupled to a distal portion of the boom assembly. At least one tilt cylinder is coupled to the boom assembly and the attachment coupler. An attachment is coupled to the attachment coupler. The attachment comprises an attachment frame coupled to the attachment coupler. The attachment frame has a lower portion and an upper portion. A joint is coupled to the lower portion of the attachment frame and a blade. The joint has an upper surface and a lower surface positioned a distance from the surface. An angle cylinder is coupled to the lower portion of the attachment frame and a blade. A portion of the angle cylinder is positioned below the upper surface.

A work vehicle comprising a frame supported by a ground engaging device. A boom assembly is coupled to the frame. A boom cylinder is coupled to the frame and the boom assembly. An attachment coupler is coupled to a distal portion of the boom assembly. At least one tilt cylinder is coupled to the boom assembly and the attachment coupler. An attachment is coupled to the attachment coupler. The attachment comprises an attachment frame coupled to the attachment coupler. The attachment frame has a lower portion and an upper portion. A joint is coupled to the lower portion of the attachment frame and a blade. The joint has an upper surface and a lower surface positioned a distance from the surface. An angle cylinder is coupled to the lower portion of the attachment frame and a dozer blade. A portion of the angle cylinder is positioned below the upper surface.

An earth levelling blade assembly for mounting on the lift arms of a loader includes a laterally extending main blade and two shoes supported at opposing ends of the main blade for sliding engagement along the ground. The shoes are supported for movement between a forward position ahead of the main blade and a rearward position behind the main blade, as well as being adjustable in height relative to a bottom cutting edge of the main blade. A coupling arrangement between a first mounting frame on the lift arms of the loader and a second mounting frame on the rear mounting face of the main blade (i) supports the second mounting frame to be freely pivotal about a forward axis relative to the first mounting frame in which the forward axis is oriented in the forward working direction of the loader and (ii) supports the second mounting frame to freely translate relative to the first mounting frame along an upright axis.

A dozer blade attachment control system for a work machine comprises a dozer blade attachment coupled to the attachment coupler, a hydraulic circuit, and an electronic controller. The hydraulic circuit comprises a hydraulic pump, a diverter valve operable in a first position and second position, and a pressure compensated directional control valve. The electronic controller is communicatively coupled to the hydraulic circuit. The electronic circuit may modify the hydraulic circuit to one or more of a first configuration with the diverter valve in the first position for tilt, a second configuration with the diverter valve in the second position for angling, and a third configuration with the diverter valve in the second position and the pressure compensated directional control valve creating a shuttle flow path from a higher and a lower side of the hydraulic circuit for simultaneously tilting and angling.

Methods and systems are described for estimating yaw of an implement relative to a machine. The yaw is estimated using gyro signals. The gyro signals may be provided by gyro sensors such as IMUs that are coupled to the implement and machine.

A controller determines that a signal from an operating device represents either a normal operation to manually control a blade or a trigger operation to automatically control the blade. The controller moves the blade so that the angle of the blade is changed in accordance with the operation of the operating device when the signal from the operating device is determined as representing a normal operation. The controller moves the blade until the angle of the blade reaches a predetermined target angle when the signal from the operating device is determined as representing the trigger operation while the bulldozer is traveling.

A dozer blade assembly for connection to a vehicle having a vertically movable mount, the dozer blade assembly including a blade connected to a blade support frame by a universal joint, and being pivotally movable relative to the blade support frame about a vertical yaw axis so as to turn left or right, about a lateral pitch axis so as to rotate forward or rearward, and about a longitudinal roll axis so as to tilt left or right. The dozer blade assembly further includes at least one yaw actuator, at least one pitch actuator and at least one roll actuator, with the actuators connected to the blade and to the blade support frame in locations that permit compound movements of the blade relative to the blade support frame.