Patent ID: 6067782
Filing Date: 2000-05-30
Classification: A01B,B62D

Abstract:
In an electrohydraulic steering system for machines, having steerable wheels, which has manual steering and automatic steering (autopilot) modes which can be selectively activated, and including a hydraulic steering cylinder for displacement of the steerable wheels, a sensor for determining in each case wheel angle actual values for said wheels, means for regulating flow of hydraulic fluid to the steering cylinder, an automatic steering signal transmitter operative in the automatic steering mode for generating electrical steering signal nominal values for the wheel angles, and an electronic control and analysis device for receiving the generated automatic steering signal nominal values and the wheel angle actual values, and therefrom determining an automatic steering mode electrical trigger signal for the hydraulic control valve;the improvement comprising a manual steering signal transmitter operative in the manual steering mode for sensing a manual steering movement and generating a corresponding manual steering signal nominal value, means for feeding the manual steering signal nominal value to the control and analysis device, and the control and analysis device being arranged for determining, using the wheel angle actual value and the manual steering signal nominal value, a manual steering mode electrical trigger signal for said means for regulating flow of hydraulic fluid to the steering cylinder.