Abstract: A braking system is disclosed. The braking system may include a controller configured to determine a power limit for one or more brakes of a machine based on a temperature of the one or more brakes during engagement of the one or more brakes according to a commanded power. The power limit may be a power at which the temperature of the one or more brakes ceases to increase. The controller may be configured to determine a speed adjustment for the machine based on the power limit and the commanded power, and cause adjustment to a speed of the machine based on the determined speed adjustment.

Abstract: A braking system is disclosed. The braking system may include a controller configured to determine a power limit for one or more brakes of a machine based on a temperature of the one or more brakes during engagement of the one or more brakes according to a commanded power. The power limit may be a power at which the temperature of the one or more brakes ceases to increase. The controller may be configured to determine a speed adjustment for the machine based on the power limit and the commanded power, and cause adjustment to a speed of the machine based on the determined speed adjustment.

Abstract: A control system for controlling operation of a drive motor includes an input device for providing a command signal that is indicative of a desired speed and direction of rotation of the drive motor. A sensor is associated with the drive motor and adapted to provide a sensor signal indicative of current rotational speed of the drive motor. A controller receives the command signal, and determine whether the command signal is indicative of a desired zero speed to be associated with the drive motor. The controller also receives the sensor signal, and determine whether the current rotational speed of the drive motor is within a pre-defined range of difference from the desired zero speed. The controller then generates a de-rated torque command signal having a reduced gain factor, and reduce the current rotational speed of the drive motor based on the de-rated torque command signal.

Abstract: A work machine with a mechanical brake touch-up system includes a power source that provides power to a rotational element. The work machine includes a brake that is configured with a piston to selectively engage a frictional element rotationally coupled to the rotational element, a position sensor for generating a position signal of the piston, and a control valve configured to supply hydraulic pressure to the piston to selectively apply a retarding torque to the frictional element, a speed sensor for generating a rotational speed signal. The work machine includes a touch-up controller which is configured to detect a retarding condition of the work machine based on the speed signal, and, upon detection of a retarding condition, control the position of the piston to a touch-up position between an engaged and retracted position.

Abstract: A control system for a machine having at least one control element is disclosed. The control system includes multiple input sensors in communication with the control element. The input sensor generates an input signal based on an input to the control element. The control system includes multiple actuating members to control operations of the machine. The control system includes a controller in communication with the input sensors and the actuating members. The controller receives the input signal from the input sensor and determines an imposed hysteresis level corresponding to the input signal based on a hysteresis input function. The controller is further configured to generate a hysteresis conditioned input signal based on the imposed hysteresis level.

Abstract: A control system for controlling operation of a drive motor includes an input device for providing a command signal that is indicative of a desired speed and direction of rotation of the drive motor. A sensor is associated with the drive motor and adapted to provide a sensor signal indicative of current rotational speed of the drive motor. A controller receives the command signal, and determine whether the command signal is indicative of a desired zero speed to be associated with the drive motor. The controller also receives the sensor signal, and determine whether the current rotational speed of the drive motor is within a pre-defined range of difference from the desired zero speed. The controller then generates a de-rated torque command signal having a reduced gain factor, and reduce the current rotational speed of the drive motor based on the de-rated torque command signal.

Abstract: A control system for a machine having at least one control element is disclosed. The control system includes multiple input sensors in communication with the control element. The input sensor generates an input signal based on an input to the control element. The control system includes multiple actuating members to control operations of the machine. The control system includes a controller in communication with the input sensors and the actuating members. The controller receives the input signal from the input sensor and determines an imposed hysteresis level corresponding to the input signal based on a hysteresis input function. The controller is further configured to generate a hysteresis conditioned input signal based on the imposed hysteresis level.

Abstract: A system and method are provided for maintaining hydraulic steering for a machine during engine out or engine lugging conditions. The machine includes a torque-controlled transmission driven by an engine, the engine further being linked to a hydraulic steering pump that provides hydraulic power to a steering actuator. The machine may be, for example, a wheel loader or an off highway truck. The system and method include detecting an undesirable reduction of engine speed while the machine is travelling, and responsively reducing the transmission power to maintain the engine speed at a desired level to power the hydraulic steering pump. When the reduced requested transmission power reaches zero, a power reversal through the transmission is commanded to maintain the engine speed at the desired level to power the hydraulic steering pump.

Abstract: A system and method are provided for controlling a movable element in accordance with a speed command. The movable element, which may be an excavator swing platform, is moved via an actuator that is driven in accordance with a torque command. The speed of the movable element is sensed, and a torque command is generated via PID control based on the speed command and the sensed speed. The PID control uses a set of gains including a P-gain, an I-gain, and a D-gain. At least one of these gains is set based on a counter, and the counter is set, cleared, incremented, or decremented based on one or more of the speed command, the torque command and the sensed speed. In this way, the movable element responds aggressively to operator input, but stability is maintained.

Abstract: A system and method are provided for maintaining hydraulic steering for a machine during engine out or engine lugging conditions. The machine includes a torque-controlled transmission driven by an engine, the engine further being linked to a hydraulic steering pump that provides hydraulic power to a steering actuator. The machine may be, for example, a wheel loader or an off highway truck. The system and method include detecting an undesirable reduction of engine speed while the machine is travelling, and responsively reducing the transmission power to maintain the engine speed at a desired level to power the hydraulic steering pump. When the reduced requested transmission power reaches zero, a power reversal through the transmission is commanded to maintain the engine speed at the desired level to power the hydraulic steering pump.

Abstract: A method regulates the torque output and/or speed output of a continuously variable transmission (CVT) in a manner that may simulate a clutch. The CVT may be incorporated in a machine and maybe operatively coupled to a power source and to a propulsion device. The method utilizes an unaltered torque-to-speed curve that relates the torque output to the speed output of the CVT. The method may receive an operator input signal indicating a desire to change operation of the machine. The torque-to-speed curve may be shifted in response to the operator input signal to limit the torque output available. In an aspect, an under-run curve may be applied to the torque-to-speed curve, the under-run curve corresponding to a target speed. The operator input signal may also shift the under-run curve to reduce the target speed.

Abstract: A system and method are provided for controlling a movable element in accordance with a speed command. The movable element, which may be an excavator swing platform, is moved via an actuator that is driven in accordance with a torque command. The speed of the movable element is sensed, and a torque command is generated via PID control based on the speed command and the sensed speed. The PID control uses a set of gains including a P-gain, an I-gain, and a D-gain. At least one of these gains is set based on a counter, and the counter is set, cleared, incremented, or decremented based on one or more of the speed command, the torque command and the sensed speed. In this way, the movable element responds aggressively to operator input, but stability is maintained.

Abstract: A machine is described that includes an engine, a multi-clutch transmission and a controller. The controller is configured with computer-executable instructions for managing operation of the multi-clutch transmission to avoid autoengagement of a disengaged clutch. The computer-executable instructions configure the controller to receive sensor signals indicative of current operating status of the machine; determine, based upon the sensor signals, a configured minimum engine speed needed to avoid autoengagement of the disengaged clutch; and conditionally increase an engine speed based upon a comparison of the configured minimum engine speed and a sensed current engine speed.

Abstract: A machine is described that includes an engine, a multi-clutch transmission and a controller. The controller is configured with computer-executable instructions for managing operation of the multi-clutch transmission to avoid autoengagement of a disengaged clutch. The computer-executable instructions configure the controller to receive sensor signals indicative of current operating status of the machine; determine, based upon the sensor signals, a configured minimum engine speed needed to avoid autoengagement of the disengaged clutch; and conditionally increase an engine speed based upon a comparison of the configured minimum engine speed and a sensed current engine speed.

Abstract: A variator torque control system adjusts a variator output so that the actual output torque of the variator closely matches an expected output torque. In an example, pressure values of an existing torque control map are supplemented in real time with calculated pressure supplement values based on the current operation of the variator. The pressure supplement value for each mapped pressure value may be derived based on a prior application of the same or another map value.

Abstract: A swing drive system for an upper structure of a machine includes an electric motor that receives electrical power and a torque command signal. A sensor provides a sensor signal indicative of a swing speed. An electronic controller provides the torque command signal to the electric motor in response to the command signal by receiving the command and sensor signals, providing the torque command signal to maintain a swing motion of the upper structure during a normal operating state, and providing the torque command signal based on the sensor signal to brake the swing motion at a substantially constant rate when the command signal is indicative of a zero desired swing speed during a braking operating state.

Abstract: A system and method for variator control employs positively directed electronic make-up and flushing relief valves for more precise torque control of a hydraulic variator, especially during torque reversal, as well as improved cold weather operation. This can improve machine response during periods of severe torque change. The ability to more tightly control variator torque allows more precise torque management algorithms for power control and engine matching purposes. Moreover, the ability to positively control venting of the hydraulic circuit for purposes of fluid cooling allows for more consistent machine response regardless of ambient temperature.

Abstract: A calibration system for calibrating a transmission provides a calibrated clutch fill time for an oncoming clutch by activating a parking brake of a machine associated with the transmission and calibrating each clutch by setting a transmission characteristic parameter to an initial value, and then activating a clutch solenoid associated with the clutch. The transmission characteristic is periodically measured, and when the measured value of the transmission characteristic exceeds the initial value for a predetermined number of consecutive periods, the fill time for the clutch is set equal to the time elapsed during the total number of measurement periods minus one less than the predetermined number of consecutive periods.

Abstract: A hydraulic motor system for improved frequency response includes a hydraulic variator having a pump and a motor, wherein the pump includes a variable angle swash plate, and the system further includes an electric actuator for controlling an angle or torque of the swash plate, thereby controlling the motor output characteristics. The electric actuator for controlling the variable angle swash plate may comprise a linear electric motor, ball screw drive or a rotary electric motor. In an example, the rotary electric motor tilts the swash plate by applying a torque to the swash plate at a point away from its tilt axis. In a further example, the rotary electric motor tilts the swash plate via a worm drive or ball screw drive.

Abstract: A variator torque control system adjusts a variator output so that the actual output torque of the variator closely matches an expected output torque. In an example, pressure values of an existing torque control map are supplemented in real time with calculated pressure supplement values based on the current operation of the variator. The pressure supplement value for each mapped pressure value may be derived based on a prior application of the same or another map value.