WORK VEHICLE AUTOMATIC STEERING SYSTEM

An automatic steering system for a working vehicle, for automatic maneuvering of the working vehicle running on a working ground surface along a desired running path, in which the influences of various ground surface environments and of any aging degradation and/or individual variation of the working vehicle may be minimized, and the automatic steering operation may be conducted with improved stability. The automatic steering system includes: a measurement section 14 for acquiring measurements including those of the position, velocity, heading direction, and attitude of the vehicle; and a data processing section 12. The data processing section 12 includes: a vehicle related parameter estimator 122 for determining a value of a vehicle related parameter; a ground surface related parameter estimator 124 for determining a value of a ground surface related parameter; and a steering amount value generator 126 for generating a desired steering amount value on the basis of the determined values of the vehicle related parameter and the determined value of the ground surface related parameter. The automatic steering system 10 is adapted for operation (i) in a pre-adjustment mode as well as (ii) in a working mode which is to be adopted when the working vehicle runs on the working ground surface. During an operation of the automatic steering system in the pre-adjustment mode, the vehicle related parameter estimator 122 determines the value of the vehicle related parameter on the basis of the measurements acquired by the measurement section 14. During an operation of the automatic steering system in the working mode, the vehicle related parameter estimator 122 updates the value of the vehicle related parameter and the ground surface related parameter estimator 124 determines the value of the ground surface related parameter on the basis of the measurements acquired by the measurement section 14.