A method of operating a driveline including a powersplit transmission is provided. The driveline may be operated in a hydrostatic power transmission mode and a blended hydrostatic/mechanical power transmission mode. The method comprises the steps of providing a hydrostatic circuit, detecting a rapid deceleration of the vehicle, and adjusting a threshold of at least one pressure relief valve forming a portion of the hydrostatic circuit in response to the sudden deceleration. The at least one pressure relief valve facilitates quickly changing the driveline from the blended hydrostatic/mechanical power transmission mode to the hydrostatic power transmission mode.

A method is provided for controlling the speed of a vehicle that includes a drive train for driving the vehicle and a predetermined preferred speed set. The method includes determining whether or not a substantially constant speed of the vehicle is requested, if it is determined that a substantially constant speed is requested, determining whether the requested speed lies within or outside of the predetermined preferred speed set, and if it is determined that the requested speed lies outside of the predetermined speed set, automatically adjusting the speed of the vehicle to a vehicle speed that is within the predetermined speed set.

A control system for a work machine having an upper frame rotatably mounted to a lower frame includes a controller configured to limit a maximum speed of the machine when a rotation angle between the upper frame and the lower frame exceeds a first predetermined value.

Described herein are systems, methods, and other techniques for controlling a velocity of a construction machine operating within a construction site. Sensor data is captured using one or more sensors of the construction machine while the construction machine is moving at the velocity in a forward or a backward direction. An actual surface of the construction site is estimated based on the sensor data. A deviation between a target surface and the actual surface is calculated. An actual performance metric is calculated based on the deviation. The actual performance metric is compared to a target performance metric to determine a velocity adjustment. The velocity of the construction machine is adjusted by the velocity adjustment.

A hydraulic system for a work machine includes a hydraulic bump to output an operation fluid, a hydraulic switch valve to be switched among switching positions in accordance with a pressure of the operation fluid, a proportional valve to change the pressure of the operation fluid applied to the hydraulic switch valve, a travel hydraulic device to change a thrust power in accordance with the switching positions of the hydraulic switch valve. And, the hydraulic system includes a controller to control the proportional valve in accordance with a state of the travel hydraulic device.

A battery-operated work machine is provided which can perform a work while avoiding such a situation that the work machine cannot reach charging equipment. When the remaining capacity of a battery becomes lower than a first threshold value set in advance, a controller controls an inverter such that the revolution speed of an electric motor is kept at a target revolution speed and controls a first notification device to operate, and besides switches a traveling motor to a travel first speed side, in which the displacement volume is a large volume, irrespective of an input from a traveling mode instruction device, when the remaining capacity of the battery becomes lower than a first threshold value set in advance.

A working machine includes a controller configured or programmed to perform an automatic deceleration for automatically decelerating a left traveling motor and a right traveling motor rotated at a second speed by shifting from the second speed to the first speed, and to determine a deceleration threshold that is used for judging whether the automatic deceleration has to be performed or not.

A working machine includes a controller configured to determine a first deceleration threshold corresponding to each of a first traveling pressure, a second traveling pressure, a third traveling pressure, and a fourth traveling pressure, to perform automatic deceleration to reduce rotation speeds of a left traveling motor and a right traveling motor, and to judge whether to perform the automatic deceleration based on the determined first deceleration threshold, the first traveling pressure, the second traveling pressure, the third traveling pressure, and the fourth traveling pressure.

A working machine includes a prime mover, a traveling device, a traveling motor configured to output power to the traveling device, a speed shifting valve configured to shift an output speed of the traveling motor between a first speed and a second speed faster than the first speed, an actuation valve configured to change a hydraulic pressure applied to the speed shifting valve, a first fluid passage fluidly connected to the speed shifting valve so that hydraulic fluid having the hydraulic pressure to be applied to the speed shifting valve flows through the first fluid passage, a drain fluid passage fluidly connected to the first fluid passage, a brake shiftable between a braking state to brake the traveling motor and a braking releasing state to release the braking, and a controller configured or programmed to control the actuation valve and the brake, and being capable of activate a warm-up mode. The controller, when activating the warm-up mode, is configured or programmed to shift the brake into the braking state, and control the actuation valve so as to make the hydraulic pressure to be applied to the speed shifting valve equal to or greater than a value corresponding to the second speed.

A working machine includes a controller to perform an automatic deceleration operation to automatically decelerate from a second speed to a first speed when a value calculated based on a first traveling pressure, a second traveling pressure, a third traveling pressure, and a fourth traveling pressure becomes equal to or more than a deceleration threshold in a state where a left traveling motor and a right traveling motor are being driven at the second speed. The controller determines the deceleration threshold based on any one of a first cross-differential pressure acquired by subtracting the fourth traveling pressure from the first traveling pressure, a second cross-differential pressure acquired by subtracting the third traveling pressure from the second traveling pressure, a third cross-differential pressure acquired by subtracting the second traveling pressure from the third traveling pressure, and a fourth cross-differential pressure acquired by subtracting the first traveling pressure from the fourth traveling pressure.