Method of determining a set value of the assisting force in a power steering system
First Claim
1. A method of determining a set value of the assisting force in a power steering system of a vehicle, comprising the steps of:
- (a) estimating a general driving situation with respect to cornering force taking place by deriving a variable representing a set value of lateral acceleration from a steering angle, deriving a variable representing said lateral acceleration and thereby deriving a critical driving state during vehicle cornering by a reduction in correlation of the lateral acceleration and steering angle variables when a steering wheel of the power steering system has moved away from a neutral position by a driver of the vehicle from a deviation of said variable representing said lateral acceleration from said set value of said lateral acceleration exceeding a threshold value; and
(b) reducing an assisting force in the power steering system experienced by the vehicle driver during turning and returning movements of the steering wheel as a function of steering angular velocity only during the critical driving state to reduce instabilities induced by the vehicle driver in critical driving situations.
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Abstract
A method of determining a set value of the assisting force in a power steering system reduces the assisting force in the power steering system as a function of the steering angular velocity (LWG). An estimate of the general driving situation with respect to the cornering force taking place by a variable representing a set value (ayset) of the lateral acceleration is derived from the steering angle (LW), by determining a variable representing the lateral acceleration (ay) and by deriving a critical driving state from a deviation of the variable representing the lateral acceleration (ay) from the variable representing the set value (ayset) of the lateral acceleration above a threshold value. The reduction of the assisting force in the power steering system as a function of the steering angular velocity LWG takes place only as long as the critical driving state is detected.
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Citations
32 Claims
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1. A method of determining a set value of the assisting force in a power steering system of a vehicle, comprising the steps of:
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(a) estimating a general driving situation with respect to cornering force taking place by deriving a variable representing a set value of lateral acceleration from a steering angle, deriving a variable representing said lateral acceleration and thereby deriving a critical driving state during vehicle cornering by a reduction in correlation of the lateral acceleration and steering angle variables when a steering wheel of the power steering system has moved away from a neutral position by a driver of the vehicle from a deviation of said variable representing said lateral acceleration from said set value of said lateral acceleration exceeding a threshold value; and (b) reducing an assisting force in the power steering system experienced by the vehicle driver during turning and returning movements of the steering wheel as a function of steering angular velocity only during the critical driving state to reduce instabilities induced by the vehicle driver in critical driving situations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification