WORK VEHICLE, AND CONTROL DEVICE AND CONTROL METHOD FOR WORK VEHICLE

A required output torque determination unit determines a required output torque of a power transmission device based on an operation amount of an operation device and a traveling speed of a work vehicle. A traveling load estimation unit estimates a traveling load torque related to a traveling load on the work vehicle based on a torque of a drive source, a rotation speed ratio of the power transmission device, and a rotation speed of an output shaft. A required output torque correction unit 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. A drive source control unit outputs a control signal for the drive source based on a corrected required output torque.