| 主权项 |
1. A steerable, self-propelled vehicle including an agricultural tractor, the steerable self-propelled vehicle comprising:
a steering mechanism having a rotatable steering column that is connected to control a steering angle of one or more ground-engaging members of the vehicle, the vehicle including
a first steering servomechanism acting on the steering mechanism in a first location, the first steering servomechanism including a hydraulic steering servomechanism including a hydraulic steering valve that generates a pilot hydraulic signal in relation to the rotational angle of the steering column and at least one hydraulic steering cylinder connected to adjust the steering angle of the one or more ground-engaging members, the pilot hydraulic signal being piloted to control the hydraulic steering cylinder, the first steering servomechanism having at least a first steering assistance characteristic;a second steering servomechanism acting on the steering mechanism in a second location, the second steering servomechanism including an electric power steering servomechanism including a motor for generating a torque that acts on the steering column, and a signal generator for generating control signals determining the magnitude and direction of action of the torque, the second servo mechanism having a second steering assistance characteristic; anda programmable controller for causing the first and second steering assistance characteristics to influence the steering of the vehicle in dependence on one or more control commands generated in the controller, wherein the vehicle includes a human-machine interface (HMI) using which a driver may input commands selecting two or more programmed modes of operation of the steering servomechanisms, wherein the HMI includes switching interfaces for selecting between programmed modes that control steering during movement of the tractor respectively in a field headland and in other locations, wherein the HMI includes respective switches for selecting the programmed modes and sequentially selecting sub-modes following selection of a said programmed mode, and wherein the sub-modes available following selection of headland operation include a damped steering sub-mode, a maximal assistance sub-mode, an automatic steering centring sub-mode, and a lock-to-lock assistance sub-mode, and the sub-modes available following selection of other location operation include an on-road sub-mode, a damped steering sub-mode, and a maximal assistance sub-mode. |
