Electrohydraulic steering system
First Claim
1. 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.
1 Assignment
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Accused Products
Abstract
An electrohydraulic steering system for machines includes manual steering and automatic steering (autopilot) modes which can be activated by a switch (3). The system has a hydraulic steering cylinder (6) for displacement of the steerable wheels, at least one sensor (7) for determining the wheel angle actual values (δw), at least one electrically operated hydraulic control valve (5) which regulates admission of hydraulic fluid to the steering cylinder (6) and at least one automatic steering signal transmitter (2) for generating electrical steering signal nominal values (δs2) for the wheel angles. An electronic control and analysis device (4) is fed the automatically generated steering signal nominal values (δs2) and the wheel angle actual values (δw). The control and analysis device (4) determines an electrical trigger signal (4S) for the hydraulic control valve (5) from the wheel angle actual value (δw) and the automatically generated steering signal nominal value (δs2) . A steering signal transmitter (1) is provided for the manual steering, which from a manual steering movement generates a corresponding electrical steering signal nominal value (δs1) which is also fed to the control and analysis device (4). Depending on which steering mode is active, the control and analysis device (4) analyses the manual or automatic steering signal nominal values.
51 Citations
50 Claims
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1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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19. 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, and wherein the control and analysis device includes an error detection unit, and first and second control and analysis units independent of each other;
said units being arranged to each receive the steering signal nominal values, and the wheel angle actual values; and
the control and analysis units being connected to the error detection unit for the exchange of analysis results, and in case of an error the erroneous control and analysis unit being deactivated by the error detection unit, the steering system having a first separate control and analysis tool having an independent power supply provided for the first control and analysis unit, and having a second control and analysis tool having a separate independent power supply provided for the second control and analysis unit and the error detection unit together.
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50. An electrohydraulic steering system for machines, having steerable wheels, which have manual steering and automatic steering modes which can be selectively activated, and including
a hydraulic steering cylinder for displacement of the steerable wheels, a sensor for determining wheel angle actual values for said wheels, means for regulating flow of hydraulic fluid to the steering cylinder, and an electronic control and analysis device; -
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; an automatic steering signal transmitter operative in the automatic steering mode for generating electrical steering signal nominal values for the wheel angles, means for feeding the automatic steering signal nominal values to the control and analysis device, and the electronic control and analysis device being arranged for determining, using the automatically generated steering signal nominal values and the wheel angle actual values, an automatic steering mode electrical trigger signal for the hydraulic control valve.
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Specification