A blade control method includes: acquiring a design surface indicating a target shape of an excavation object to be excavated by a blade supported by a vehicle body of a work vehicle, the design surface including a first surface present in front of the work vehicle and a second surface disposed below the first surface and forming a level difference with a front end portion of the first surface; acquiring an observed pitch angle indicating an inclination angle of the vehicle body in a longitudinal direction; and calculating a specific part height indicating a height-direction distance between a specific part of the work vehicle and the second surface in a state in which at least a part of the vehicle body is positioned on the first surface and the blade is positioned above the second surface.

A blade control device includes: a corrected design surface generation unit that generates a corrected design surface connecting a first surface existing in front of a work vehicle and a second surface having a different slope from a slope of the first surface on an initial design surface indicating a target shape of an excavation object to be excavated using a blade of the work vehicle; and a blade control unit that outputs a control command to control a height of the blade based on the corrected design surface.

A controller acquires a size of a recess included in an actual topography within a work range. The controller determines whether the size of the recess is larger than a predetermined recess threshold. When the size of the recess is larger than the predetermined recess threshold, the controller determines a first area and a second area divided at a position of the recess in the work range. The controller determines a first target design topography indicative of a target trajectory of a work implement for the first area. The controller generates a command signal to operate the work implement according to the first target design topography.

A system includes a receiver mounted on a work machine, and a processor. The receiver receives a signal usable to identify a position of the work machine. The processor acquires a position of the receiver from the signal received by the receiver. The processor acquires a calculated position of a calibration point in the work machine by calculating a position of the calibration point from the position of the receiver. The processor acquires an actual position of the calibration point. The processor generates calibration data usable to calibrate a position of a reference point in the work machine by comparing the actual position with the calculated position of the calibration point.

A work vehicle includes a work implement. A control system for the work vehicle includes a controller programmed to acquire actual topography data indicating an actual surface of a work target, and replace the actual surface with a design surface.

A work vehicle control system includes an actual topography acquisition device, a storage device, a soil amount acquisition device, and a controller. The actual topography acquisition device acquires actual topography information, which indicates an actual topography of a work target. The storage device stores design topography information, which indicates a final design topography of the work target. The soil amount acquisition device generates a soil amount signal indicating a held soil amount of the work implement. The controller acquires the actual topography information from the actual topography acquisition device, the design topography information from the storage device, and the soil amount signal from the soil amount acquisition device. The controller determines an intermediate design topography positioned above the actual topography and below the final design topography in accordance with the held soil amount. The controller generates a command signal to move the work implement based on the intermediate design topography.

A work vehicle includes a work implement. A control system for the work vehicle includes an operating device that outputs an operation signal indicative of an operation by an operator, and a controller that communicates with the operating device and controls the work implement. The controller determines a target design topography indicative of a target topography. The controller generates a command signal to operate the work implement in accordance with the target design topography. When a tilt angle of the work implement is changed with an operation of the operating device, the controller corrects the tilt angle of the work implement in accordance with the changed tilt angle.

A control system for a work vehicle includes a controller. The controller acquires actual topography data indicating an actual topography to be worked. The controller determines a target design topography indicating a target trajectory of a work implement of the work vehicle based on the actual topography. The controller acquires an uneven surface parameter indicating the degree of surface unevenness of the actual topography. The controller changes the target design topography according to the uneven surface parameter.

An earthmoving system includes a blade, a controller, and a blade control system configured to control the positioning of the blade. While grading, the earthmoving system is configured to simultaneously position the blade according to each of a fixed slope grading mode, a design driven control grading mode, and an fixed load grading mode.

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.