Methods and systems for controlling a hydromechanical transmission are proposed. In one example, a control method for a hydrostatic unit of a hydromechanical variable transmission (HVT) is presented, comprising controlling the hydrostatic unit via a feedforward control architecture including a non-linear, multi-coefficient model, wherein the hydrostatic unit comprises a hydrostatic pump and a hydrostatic motor. A desired differential pressure of the hydrostatic unit or a desired hydraulic pump displacement may be used as inputs for the model, where the model's output is a pressure difference for a pump control piston coupled to a swash plate of the hydrostatic unit. Use of the non-linear model permits the hydrostatic unit to be controlled based on load, speed, and/or torque, thereby increasing the adaptability of the control system.

Methods and systems for controlling a hydromechanical transmission are proposed. In one example, a control method for a hydrostatic unit of a hydromechanical variable transmission (HVT) is presented, comprising controlling the hydrostatic unit via a feedforward control architecture including a non-linear, multi-coefficient model, wherein the hydrostatic unit comprises a hydrostatic pump and a hydrostatic motor. A desired differential pressure of the hydrostatic unit or a desired hydraulic pump displacement may be used as inputs for the model, where the model's output is a pressure difference for a pump control piston coupled to a swash plate of the hydrostatic unit. Use of the non-linear model permits the hydrostatic unit to be controlled based on load, speed, and/or torque, thereby increasing the adaptability of the control system.

Methods and systems for transmission control are provided. In one example, a transmission system operating method includes maintaining a displacement set-point of a variable displacement hydraulic motor in a hydrostatic assembly within a working zone, where at least a portion of a boundary of the working zone is determined based on a torque constraint of the hydrostatic assembly. The transmission system includes the hydrostatic assembly that includes the hydraulic motor that is hydraulically coupled in parallel with a variable displacement hydraulic pump and a gearbox mechanically coupled to the hydrostatic assembly and including one or more clutches.

A hydrostatic transmission pressure monitoring system includes a hydrostatic transmission and a pressure sensor data source. The hydrostatic transmission includes, in turn, a transmission casing, a pivoting yoke assembly rotatably mounted in the transmission casing, a hydrostatic pump-motor arrangement containing a hydraulic pump-motor circuit at least partially formed in the pivoting yoke assembly, and a pressure scaling device fluidly coupled to the hydraulic pump-motor circuit. The pressure scaling device is configured to generate a pressure-scaled output signal substantially proportional to a peak circuit pressure within the hydraulic pump-motor circuit. The pressure sensor data source is fluidly coupled to the pressure scaling device and is configured to generate pressure sensor data indicative of the pressure-scaled output signal.

A control device of a work vehicle includes a required output torque determination unit that determines a required output torque of the power transmission device based on an operation amount of the operation device and a traveling speed of the work vehicle, a traveling load estimation unit that estimates a traveling load torque related to a traveling load on the work vehicle, a required output torque correction unit that corrects the required output torque such that the required output torque is included in an allowable output torque range including an estimated traveling load torque, and a drive source control unit that outputs a control signal for the drive source based on a corrected required output torque.

Methods and systems for controlling a hydromechanical transmission are proposed. In one example, a control method for a hydrostatic unit of a hydromechanical variable transmission (HVT) is presented, comprising controlling the hydrostatic unit via a feedforward control architecture including a non-linear, multi-coefficient model, wherein the hydrostatic unit comprises a hydrostatic pump and a hydrostatic motor and a desired differential pressure of the hydrostatic unit or a desired hydraulic pump displacement may be used as inputs for the model, where the model’s output is a pressure difference for a pump control piston coupled to a swash plate of the hydrostatic unit. Use of the non-linear model permits the hydrostatic unit to be controlled based on load, speed, and/or torque, thereby increasing the adaptability of the control system.

Methods and systems for controlling a hydromechanical transmission are proposed. In one example, a control method for a hydrostatic unit of a hydromechanical variable transmission (HVT) is presented, comprising controlling the hydrostatic unit via a feedforward control architecture including a non-linear, multi-coefficient model, wherein the hydrostatic unit comprises a hydrostatic pump and a hydrostatic motor and a desired differential pressure of the hydrostatic unit or a desired hydraulic pump displacement may be used as inputs for the model, where the model’s output is a pressure difference for a pump control piston coupled to a swash plate of the hydrostatic unit. Use of the non-linear model permits the hydrostatic unit to be controlled based on load, speed, and/or torque, thereby increasing the adaptability of the control system.

Methods and systems for a hydromechanical transmission in a vehicle are provided herein. In one example, the transmission system includes a hydrostatic assembly with a hydraulic pump in fluidic communication with a hydraulic motor. The transmission system further includes a controller configured to selectively transition between a torque control mode and a speed control mode of the hydrostatic assembly while the vehicle is on a slope.

Methods and systems for a hydromechanical transmission in a vehicle are provided herein. In one example, the transmission system includes a hydrostatic assembly with a hydraulic pump in fluidic communication with a hydraulic motor. The transmission system further includes a controller configured to selectively transition between a torque control mode and a speed control mode of the hydrostatic assembly while the vehicle is on a slope.

A system, for providing a rotary power to an implement of a machine, includes a first motor control valve associated with a first motor of the machine and a second motor control valve associated with a second motor of the machine. The first motor control valve is configured to be actuated at a first shift point to shift the first motor such that the first motor and the second motor switch between a first implement drive speed and a second implement drive speed. The second motor control valve is configured to be actuated at a second shift point to shift the second motor such that the first motor and the second motor switch between the second implement drive speed and a third implement drive speed. The first and second shift points are based on loading of the implement during operation. In addition, the first and second shift points are different.