Komatsu Corporation

Takahisa Oasa

Kiyotaka Ninomiya

Atsushi Shirao

Shotaro Ishii

Jun Koizumi

Shinichi Kitao

Satoshi Asami

Ai Haginiwa

Masahiro Minato

A work equipment control device of a work vehicle includes state determination unit and an automatic dump determination unit. The state determination unit determines a work state of the work vehicle based on a traction force of the work vehicle and a posture of work equipment. An automatic dump determination unit determines an automatic dump availability mode indicating the availability in performing automatic dump control for automatically driving a bucket to a predetermined dump angle, in accordance with the work state.

Work equipment control device, work vehicle, and method for controlling work equipment

A work vehicle includes an engine, a hydrostatic transmission, a work implement pump driven by the engine, a work implement driven by hydraulic fluid discharged from the work implement pump, an accelerator, a first sensor configured to output a signal indicative of an operation amount of the accelerator, a work implement operating member, a second sensor configured to output a signal indicative of an operation amount of the work implement operating member, and a controller. The controller is configured to receive signals from the first sensor and the second sensor, determine a target input horsepower input to the hydrostatic transmission from the operation amount of the accelerator, and determine a target rotational speed of the engine from the target input horsepower and the operation amount of the work implement operating member.

Work vehicle and control method for work vehicle

A work machine control device includes a lift force detection unit, a control amount determination unit, and a command output unit. The lift force detection unit detects a lift force of the work machine. The control amount determination unit determines a control amount for the work machine based on a change amount of the detected lift force. The command output unit outputs, to an actuator driving the work machine, a control command according to the determined control amount. The control amount determination unit determines the control amount such that the control amount monotonically increases with respect to the lift force until a lift amount of the work machine reaches a predetermined threshold. A work vehicle includes the work machine control device, a vehicle body, a work machine supported by the vehicle body, and an actuator that drives the work machine.

Work machine control device, work vehicle, and method of controlling work machine

A work vehicle controls an engine output based on an accelerator operation amount and a work equipment operation amount. A control device for the work vehicle includes an acceleration correction unit, a target vehicle speed determination unit, and a deceleration correction unit. The acceleration correction unit obtains a corrected accelerator operation amount by correcting the accelerator operation amount based on an inching operation amount. The target vehicle speed determination unit determines a target vehicle speed based on the corrected accelerator operation amount and a signal based on an operation of a shift operation member. The deceleration correction unit corrects the target vehicle speed based on the inching operation amount.

Work vehicle, control device for work vehicle, and control method for work vehicle

A work vehicle includes a vehicle body, a work implement including a boom attached to the vehicle body and an attachment attached to a tip end part of the boom, a first actuator configured to rotate the boom up and down, and a controller configured to execute an automatic lowering control in order to automatically rotate and lower the boom. The controller is further configured to set the first actuator to a floating state when it is detected that the attachment has reached a predetermined position during an execution of the automatic lowering control.

Work vehicle

A work vehicle includes a vehicle body, a work implement including an attachment, an operating device and a controller. The operating device can be operated to a dump side and a tilt side to cause the attachment to dump and tilt. The controller executes an automatic drive control in which the attachment is caused to dump as far as a predetermined dumping position when the operating device is operated by a first dump operation amount or greater to the dump side, or to tilt as far as a predetermined tilt position when the operating device is operated by a first tilt operation amount or greater to the tilt side. The controller disables the automatic drive control when a switching time period required for the operating device to be switched between the tilt and dump sides is at least a predetermined disabling time period.

Work vehicle with automatic dump and tilt control and method for automatically controlling dump and tilt operations of work vehicle

The controller determines whether the vehicle is in a shuttle motion from the operating position of the forward/reverse travel operating member and the actual traveling direction of the vehicle. The controller determines a target braking force when the vehicle is in the shuttle motion. The controller determines at least one of a target displacement of the travel pump and a target displacement of the travel motor based on the target braking force.

A work vehicle includes an engine, a hydrostatic transmission, a storage device storing leakage flow rate data defining a relationship between a differential pressure of hydraulic fluid between the first drive circuit and the second drive circuit and a leakage flow rate of the hydraulic fluid in the hydraulic circuit in stalling, and a controller in communication with the storage device. The hydrostatic transmission includes a traveling pump, a hydraulic circuit with first and second drive circuits, and a traveling motor. The controller is configured to determine a target traction force of the work vehicle, determine a target differential pressure that is a target value of the differential pressure from the target traction force, determine the leakage flow rate from the target differential pressure with reference to the leakage flow rate data, and determine a target flow rate of the traveling pump from the leakage flow rate.

A work vehicle includes an engine, a traveling pump driven by the engine, a hydraulic circuit connected to the traveling pump, a traveling motor connected to the traveling pump via the hydraulic circuit, a rotational speed sensor configured to output a signal indicative of engine speed a hydraulic pressure sensor configured to output a signal indicative of hydraulic pressure of the hydraulic circuit, a controller. The controller receives the signals from the rotational speed sensor and the hydraulic pressure sensor. The controller determines whether the engine is in an over-rotation state based on engine speed. The controller determines an upper limit value of a displacement of the traveling pump based on hydraulic pressure of the hydraulic circuit. The controller limits the displacement of the traveling pump to the upper limit value or less upon determining that the engine is in the over-rotation state.

A work vehicle includes a vehicle body, a work implement attached to the vehicle body, an operating device configured to operate the work implement, a controller configured to drive the work implement at a driving speed corresponding to an operation amount of the operating device, and an input device. The controller is further configured to execute an automatic drive control in order to automatically drive the work implement as far as a predetermined position at a driving speed set in response to an operation amount of the operating device when the controller has received an input from the input device while the operating device is operated.

When the vehicle speed increases and reaches a predetermined switching threshold, the controller reduces the displacement of the first travel motor and controls the flow rate control device to offset a flow rate excess in the hydraulic circuit in accordance with the reduction in the displacement of the first travel motor. After the vehicle speed has reached the switching threshold, the controller executes switching control to switch the clutch from an engaged state to a disengaged state.

A controller determines a compensation factor from an operating amount of an accelerator operating member and a hydraulic pressure of at least one of a first circuit and a second circuit. The controller determines a target vehicle speed from the operating amount of the accelerator operating member. The controller determines at least one of a target displacement of a travel pump and a target displacement of a travel motor from the target vehicle speed and the compensation factor.

A work vehicle includes an engine, a hydrostatic transmission, and a controller. The hydrostatic transmission includes a traveling pump driven by the engine, a hydraulic circuit connected to the traveling pump, and a traveling motor connected to the traveling pump via the hydraulic circuit. The controller is configured to control the traveling motor and the traveling pump, determine a target flow rate of the traveling motor or the traveling pump, determine a correction amount of the target flow rate from a hydraulic pressure of the hydraulic circuit, and determine a target displacement of the traveling motor or the traveling pump from the target flow rate and the correction amount.

A controller determines a target rotation speed of an engine from an operation amount of an accelerator operating member. The controller determines whether a vehicle is in coasting deceleration. The controller decreases a differential pressure between a first circuit and a second circuit of a hydraulic circuit according to a deviation between an actual rotation speed of the engine and the target rotation speed, or the operation amount of the accelerator operating member when the vehicle is in the coasting deceleration.

A work vehicle includes a controller. The controller is configured to determine whether low-load conditions indicating that the work vehicle is in a low-load state are satisfied. The controller is configured to control an engine so that an upper limit value of an output torque of the engine when the low-load conditions are satisfied is made less than when the low-load conditions are not satisfied. Also, the controller is configured to vary a reduction amount of the upper limit value of the output torque of the engine when the low-load conditions are satisfied, in accordance with variation in at least one of vehicle speed, vehicle acceleration, and engine-rotation-speed acceleration, and in accordance with variation in engine rotation speed.

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Tokyo, Japan

Takahisa Oasa