Abstract: A work machine and method for a work machine with an open center hydraulic system for controlling actuation of an implement includes an implement control valve, an electro-hydraulically controlled pump, a hydraulic circuit coupled to the implement actuator, and a pressure transducer positioned for measuring a pressure in the hydraulic circuit between the pump and the implement control valve. A calibration system for calibrating the pump includes a controller having a non-transitory computer readable medium having a program instruction for causing a processor to calibrate a first threshold for the pump in a pump-flow curve wherein the first threshold including a minimum current command to actuate the pump; determine a hysteresis band in the pump-flow curve; and calibrate a second threshold for the pump in the pump-flow curve wherein the second threshold including a maximum current command to actuate the pump below a relief setpoint.

Abstract: A pilot hydraulic system may include a pilot pressure source, a pilot pressure return tank, a pilot valve, a pilot pressure supply line connecting the pilot pressure source to the pilot valve, and a pilot pressure return line connecting the pilot pressure return tank to the pilot valve. A main control valve may include a pilot chamber. A pilot pressure control line connects the pilot valve to the pilot chamber. A hydraulic sub-system is provided for modifying pilot pressure provided to the pilot chamber of the main control valve. The hydraulic sub-system may include a variable orifice valve disposed in the pilot pressure control line, a pilot pressure bypass line communicating the pilot pressure control line downstream of the variable orifice valve with the pilot pressure return line, and an electrohydraulic pressure reducing valve (EHPRV) disposed in the pilot pressure bypass line.

Abstract: A pilot hydraulic system may include a pilot pressure source, a pilot pressure return tank, a pilot valve, a pilot pressure supply line connecting the pilot pressure source to the pilot valve, and a pilot pressure return line connecting the pilot pressure return tank to the pilot valve. A main control valve may include a pilot chamber. A pilot pressure control line connects the pilot valve to the pilot chamber. A hydraulic sub-system is provided for modifying pilot pressure provided to the pilot chamber of the main control valve. The hydraulic sub-system may include a variable orifice valve disposed in the pilot pressure control line, a pilot pressure bypass line communicating the pilot pressure control line downstream of the variable orifice valve with the pilot pressure return line, and an electrohydraulic pressure reducing valve (EHPRV) disposed in the pilot pressure bypass line.

Abstract: A hysteresis compensation systems and methods. Hysteresis compensation is provided using a known response curve for each of a plurality of different state conditions. In response to determining that a state transition has occurred (i.e., from one response curve to another), the system generates a transition response curve extending from an origin point on a first response curve to an end point on a second response curve based at least in part on a known or determined difference between the input value of the origin point and the input value for the end point. In some embodiments, this difference is determined experimentally and, in others, it is estimated based on measured feedback. Hysteresis compensation is then provided by identifying an input value on the transition response curve that corresponds to a target system output value for the received indicated input value (e.g., as defined by a reference curve).

Abstract: A hysteresis compensation systems and methods. Hysteresis compensation is provided using a known response curve for each of a plurality of different state conditions. In response to determining that a state transition has occurred (i.e., from one response curve to another), the system generates a transition response curve extending from an origin point on a first response curve to an end point on a second response curve based at least in part on a known or determined difference between the input value of the origin point and the input value for the end point. In some embodiments, this difference is determined experimentally and, in others, it is estimated based on measured feedback. Hysteresis compensation is then provided by identifying an input value on the transition response curve that corresponds to a target system output value for the received indicated input value (e.g., as defined by a reference curve).

Abstract: A work vehicle may comprise a chassis, a ground-engaging blade, a sensor assembly, and a controller. The ground-engaging blade may be movably connected to the chassis via a linkage configured to allow the blade to be tilted relative to the chassis. The sensor assembly may be connected to the work vehicle and configured to provide a tilt signal indicative of an angle of the blade in a roll direction and a roll signal indicative of a rotational velocity of the blade in the roll direction. The controller may be configured to determine a target tilt angle, receive the tilt signal, receive the roll signal, and send a command to tilt the blade toward the target tilt angle, the command based on the tilt signal, the roll signal, and the target tilt angle.

Abstract: A work vehicle may include a chassis, a ground-engaging blade, a sensor, and a controller. The ground-engaging blade may be movably connected to the chassis via a linkage configured to allow the blade to be raised or lowered relative to the chassis. The sensor may be connected to the chassis at a fixed relative position to the chassis and configured to provide a pitch signal indicative of a rotational velocity in a pitch direction. The controller may be configured to receive the pitch signal and send a command to raise or lower the blade, the command based on a first gain and the pitch signal when the pitch signal indicates a rotational velocity in a first direction and based on a second gain and the pitch signal when the pitch signal indicates a rotational velocity in a second direction.

Abstract: A work vehicle may comprise a chassis, a ground-engaging blade, a sensor assembly, and a controller. The ground-engaging blade may be movably connected to the chassis via a linkage configured to allow the blade to be tilted relative to the chassis. The sensor assembly may be connected to the work vehicle and configured to provide a tilt signal indicative of an angle of the blade in a roll direction and a roll signal indicative of a rotational velocity of the blade in the roll direction. The controller may be configured to determine a target tilt angle, receive the tilt signal, receive the roll signal, and send a command to tilt the blade toward the target tilt angle, the command based on the tilt signal, the roll signal, and the target tilt angle.

Abstract: A work vehicle may include a chassis, a ground-engaging blade, a sensor, and a controller. The ground-engaging blade may be movably connected to the chassis via a linkage configured to allow the blade to be raised or lowered relative to the chassis. The sensor may be connected to the chassis at a fixed relative position to the chassis and configured to provide a pitch signal indicative of a rotational velocity in a pitch direction. The controller may be configured to receive the pitch signal and send a command to raise or lower the blade, the command based on a first gain and the pitch signal when the pitch signal indicates a rotational velocity in a first direction and based on a second gain and the pitch signal when the pitch signal indicates a rotational velocity in a second direction.

Abstract: A work vehicle may include a chassis, a ground-engaging blade, a sensor assembly, and a controller. The blade may be movably connected to the chassis via a linkage assembly configured to allow the blade to be raised and lowered relative to the chassis. The sensor assembly may be configured to provide a chassis inclination signal indicative of an angle of the chassis relative to the direction of gravity and a blade inclination signal indicative of an angle of the blade relative to one of the chassis and the direction of gravity. The controller may be configured to receive the chassis and blade inclination signals, determine a target grade, determine a distance error based on the signals indicative of a distance between the blade and the target grade, and send a command to move the blade toward the target grade based on the distance error.