Abstract: A rotary mixer can include a frame, a rotor attached to the frame, four wheels attached to the frame for moving the rotary mixer, and a drive system for driving the four wheels, the drive system can include four independent hydrostatic drive loops, each of the independent hydrostatic drive loops associated with one of the wheels such that each one of the independent hydrostatic drive loops independently drives one of the four wheels; wherein the drive system includes a pressure balance mode of operation for relatively good traction ground or road conditions, and a wheel speed synchronization mode of operation for relatively poor traction ground or road conditions.

Abstract: A system is disclosed. The system may include a first hydraulic variator including a first hydraulic pump and a first hydraulic motor. A first actuator may be linked to the first hydraulic pump. The first actuator may be associated with a feedback link configured to control pressure supplied to the first actuator, via a control valve, according to the displacement of the first hydraulic pump. The system may include a second hydraulic variator including a second hydraulic pump and a second hydraulic motor. A second actuator may be linked to the second hydraulic pump and configured to control a pressure within the second hydraulic variator to correspond to a pressure within the first hydraulic variator. The system may include a controller configured to provide a first signal to the first hydraulic variator relating to a speed and a second signal to the second hydraulic variator relating to a torque.

Abstract: A rotary mixer can include a frame, a rotor attached to the frame, four wheels attached to the frame for moving the rotary mixer, and a drive system for driving the four wheels, the drive system can include four independent hydrostatic drive loops, each of the independent hydrostatic drive loops associated with one of the wheels such that each one of the independent hydrostatic drive loops independently drives one of the four wheels; wherein the drive system includes a pressure balance mode of operation for relatively good traction ground or road conditions, and a wheel speed synchronization mode of operation for relatively poor traction ground or road conditions.

Abstract: A powertrain system for a machine is described. The powertrain system includes a power source configured to provide a torque output. The powertrain system further includes a first drivetrain coupled to the power source, to drive a first set of ground engaging members, and a second drivetrain coupled to the power source to drive the second set of ground engaging members. The powertrain system further includes a controller having one or more lug curve maps defining a maximum allowed torque value of the power source for a current operating condition of the machine. The controller is configured to determine a parasitic load due to the second drivetrain, and adjust the torque output of the power source based on the determined parasitic load to maintain a rimpull performance of the machine, where the adjusted torque output is limited by the maximum allowed torque value.

Abstract: A powertrain system for a machine is described. The powertrain system includes a power source configured to provide a torque output. The powertrain system further includes a first drivetrain coupled to the power source, to drive a first set of ground engaging members, and a second drivetrain coupled to the power source to drive the second set of ground engaging members. The powertrain system further includes a controller having one or more lug curve maps defining a maximum allowed torque value of the power source for a current operating condition of the machine. The controller is configured to determine a parasitic load due to the second drivetrain, and adjust the torque output of the power source based on the determined parasitic load to maintain a rimpull performance of the machine, where the adjusted torque output is limited by the maximum allowed torque value.

Abstract: A hydrostatic drive system for a machine is disclosed. The hydrostatic drive system includes a pump, a hydraulic motor configured to receive a pressurized fluid from the pump and a controller operably connected to the pump and the hydraulic motor. The controller is configured to receive an input signal indicative of a current machine speed and a desired machine speed. Further, the controller is configured to output a motor displacement command signal and a pump displacement command signal to adjust a displacement of the hydraulic motor and the pump respectively based on the input signal to maintain at least one of constant machine speed or constant acceleration or constant deceleration during adjustment of the pump displacement and the motor displacement.

Abstract: A hydrostatic drive system for a machine is provided. The hydrostatic drive system includes a first hydraulic circuit, and a second hydraulic circuit. The first hydraulic circuit includes a first pump and a first hydraulic motor configured to selectively receive a flow of pressurized hydraulic fluid from the first pump at a first pressure. The second hydraulic circuit includes a second pump and a second hydraulic motor configured to selectively receive the flow of the pressurized hydraulic fluid from the second pump at a second pressure. The hydrostatic drive system further includes a controller configured to maintain a pressure balance between the first and the second hydraulic circuits based on a difference between the first pressure and the second pressure.

Abstract: A system for driving a machine is provided. A user input device inputs a desired throttle setting for the machine. The system includes an infinitely variable transmission having a transmission ratio that is adjustable. At least one sensor determines an inclination of the machine relative to a reference plane. A controller is configured to determine and apply a variable rate limit upon change in the transmission ratio based on the inclination of the machine when the desired throttle setting is reduced more than a predetermined amount and to adjust the rate limit based on the difference between an actual engine speed and a desired engine speed.

Abstract: A system for driving a machine is provided. A user input device inputs a desired throttle setting for the machine. The system includes an infinitely variable transmission having a transmission ratio that is adjustable. At least one sensor determines an inclination of the machine relative to a reference plane. A controller is configured to determine and apply a variable rate limit upon change in the transmission ratio based on the inclination of the machine when the desired throttle setting is reduced more than a predetermined amount and to adjust the rate limit based on the difference between an actual engine speed and a desired engine speed.

Abstract: A method of controlling a pump and motor system having at least one of a variable displacement pump and a variable displacement motor. The method may comprise providing an engine drivingly coupled to a primary load and a secondary load, the secondary load being driven by the pump and motor system. The method may also comprise sensing a change in engine speed in response to a change in the primary load. The method may further comprise changing the engine speed to compensate for the primary load change. The method may further comprise changing a displacement of the at least one variable displacement pump and the variable displacement motor to maintain a constant secondary load.

Abstract: A hydrostatic drive system for a machine is provided. The hydrostatic drive system includes a first hydraulic circuit, and a second hydraulic circuit. The first hydraulic circuit includes a first pump and a first hydraulic motor configured to selectively receive a flow of pressurized hydraulic fluid from the first pump at a first pressure. The second hydraulic circuit includes a second pump and a second hydraulic motor configured to selectively receive the flow of the pressurized hydraulic fluid from the second pump at a second pressure. The hydrostatic drive system further includes a controller configured to maintain a pressure balance between the first and the second hydraulic circuits based on a difference between the first pressure and the second pressure.

Abstract: A hydrostatic drive system for a machine is disclosed. The hydrostatic drive system includes a pump, a hydraulic motor configured to receive a pressurized fluid from the pump and a controller operably connected to the pump and the hydraulic motor. The controller is configured to receive an input signal indicative of a current machine speed and a desired machine speed. Further, the controller is configured to output a motor displacement command signal and a pump displacement command signal to adjust a displacement of the hydraulic motor and the pump respectively based on the input signal to maintain at least one of constant machine speed or constant acceleration or constant deceleration during adjustment of the pump displacement and the motor displacement.

Abstract: A machine control system may include an input receiving portion configured to receive torque inputs related to a hydrostatic transmission. The input receiving portion may also receive an operator request for actuating the hydrostatic transmission. The machine control system may also include a processor configured to determine a factor based at least in part on the torque inputs, for adjusting the operator request. The processor may also be configured to determine a command for actuating the hydrostatic transmission based on the adjusted operator request, such that a torque load to be exerted on a power source by the hydrostatic transmission is within a desired range. The machine control system may further include an output sending portion configured to send the command to the hydrostatic transmission.

Abstract: A rear wheel drive assist for an articulated machine such as a wheel tractor scraper, the machine including a first frame section having a first longitudinal axis, a second frame section with a second longitudinal axis, the first and second frame sections being pivotally connected to an articulation hitch, and an articulation sensor configured to provide an articulation angle signal indicative of an articulation angle formed between the first and second longitudinal axes. The rear wheel drive assist includes a drive motor operatively connected to the rear wheel of the machine, and a controller configured to control operation of the rear wheel drive assist based upon the articulation angle signal.

Abstract: A machine control system may include an input receiving portion configured to receive torque inputs related to a hydrostatic transmission. The input receiving portion may also receive an operator request for actuating the hydrostatic transmission. The machine control system may also include a processor configured to determine a factor based at least in part on the torque inputs, for adjusting the operator request. The processor may also be configured to determine a command for actuating the hydrostatic transmission based on the adjusted operator request, such that a torque load to be exerted on a power source by the hydrostatic transmission is within a desired range. The machine control system may further include an output sending portion configured to send the command to the hydrostatic transmission.

Abstract: A wheel tractor scraper having a rear wheel drive assist, the wheel tractor scraper includes a tractor portion pivotally coupled to a rear scraper portion, the rear scraper portion having a bowl for hauling material and a fluid powered work tool configured to assist in loading the bowl, the work tool powered by a fluid pump connected to a fluid operated work tool motor. The rear wheel drive assist includes a fluid operated drive motor coupled to the rear wheels of the machine, a diverter valve having a first position at which fluid flow is delivered from the pump to the work tool motor and a second position at which fluid flow is delivered from the pump to the drive motor, and a controller being configured to control the diverter valve to engage the rear wheel drive assist. The machine may be operated by engaging the pump and work tool motor, and then actuating the diverter valve to the second position to divert flow from the work tool motor to the drive motor.

Abstract: A hydrostatically driven vehicle has an engine operating a variable displacement propel pump, a displacement of which can vary based on an angle of a rotating swashplate, such that a fluid flow impelled by the pump transfers power to at least one propel motor rotating a wheel of the vehicle. An electronic controller of the vehicle senses an operating parameter of the system, for example, the angle of the rotating swashplate or the direction and speed of rotation of the propel motor with a sensor to yield an actual signal, and relays the actual signal to an electronic controller. The controller determines a desired angle for the rotating swashplate based on the control signal, and compares it to the actual signal from the sensor. Motion of the vehicle is stalled when the angle signal differs from the desired angle by a predetermined extent and for a predetermined period.

Abstract: A method of controlling a pump and motor system having at least one of a variable displacement pump and a variable displacement motor. The method may comprise providing an engine drivingly coupled to a primary load and a secondary load, the secondary load being driven by the pump and motor system. The method may also comprise sensing a change in engine speed in response to a change in the primary load. The method may further comprise changing the engine speed to compensate for the primary load change. The method may further comprise changing a displacement of the at least one variable displacement pump and the variable displacement motor to maintain a constant secondary load.

Abstract: A rear wheel drive assist for an articulated machine such as a wheel tractor scraper, the machine including a first frame section having a first longitudinal axis, a second frame section with a second longitudinal axis, the first and second frame sections being pivotally connected to an articulation hitch, and an articulation sensor configured to provide an articulation angle signal indicative of an articulation angle formed between the first and second longitudinal axes. The rear wheel drive assist includes a drive motor operatively connected to the rear wheel of the machine, and a controller configured to control operation of the rear wheel drive assist based upon the articulation angle signal.

Abstract: A hydrostatically driven vehicle has an engine operating a variable displacement propel pump, a displacement of which can vary based on an angle of a rotating swashplate, such that a fluid flow impelled by the pump transfers power to at least one propel motor rotating a wheel of the vehicle. An electronic controller of the vehicle senses an operating parameter of the system, for example, the angle of the rotating swashplate or the direction and speed of rotation of the propel motor with a sensor to yield an actual signal, and relays the actual signal to an electronic controller. The controller determines a desired angle for the rotating swashplate based on the control signal, and compares it to the actual signal from the sensor. Motion of the vehicle is stalled when the angle signal differs from the desired angle by a predetermined extent and for a predetermined period.