Method and device for controlling the cornering speed of a vehicle
First Claim
1. A method for controlling the cornering speed of a vehicle comprising the steps of determining a lateral acceleration and an actual speed of the vehicle, determining a yaw angular velocity of the vehicle, determining a body slip angle of the vehicle from the lateral acceleration, yaw angular velocity and actual speed of the vehicle, comparing the body slip angle with a predefined body slip-angle threshold value, taking a corrective control action in response to a deviation of the body slip angle from the body slip-angle threshold value, deriving a set speed and by means of the corrective control action, reducing the set speed of the vehicle, starting from the actual speed of the vehicle, whenever the body slip-angle threshold value is exceeded by the body slip angle.
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Abstract
The invention relates to a method and a device for controlling the cornering speed of a vehicle, with determination of the lateral acceleration and of the speed of the vehicle. In order to achieve a simple but effective capability of adjusting the vehicle speed to an optimum value, the yaw angular velocity is additionally determined, and a body slip angle is determined from the lateral acceleration, yaw angular velocity and vehicle speed. The body slip angle is compared with a threshold value. If the body slip angle exceeds this threshold, the set speed of the vehicle is reduced from the instantaneous actual speed, in a manner proportional to the body slip angle. If the body slip angle is below the threshold, the speed is released once again, or in other words the set speed is carried to the actual value of the speed; the driver can then accelerate once again. Adjustment of the set speed is achieved via adaptation of the engine torque. If the actual and set speeds differ, the engine torque is varied by a PD controller in such a way that the actual speed is adjusted to the set speed.
7 Citations
19 Claims
- 1. A method for controlling the cornering speed of a vehicle comprising the steps of determining a lateral acceleration and an actual speed of the vehicle, determining a yaw angular velocity of the vehicle, determining a body slip angle of the vehicle from the lateral acceleration, yaw angular velocity and actual speed of the vehicle, comparing the body slip angle with a predefined body slip-angle threshold value, taking a corrective control action in response to a deviation of the body slip angle from the body slip-angle threshold value, deriving a set speed and by means of the corrective control action, reducing the set speed of the vehicle, starting from the actual speed of the vehicle, whenever the body slip-angle threshold value is exceeded by the body slip angle.
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7. A device for controlling the cornering speed of a vehicle having sensors for determining the speed and lateral acceleration of the vehicle comprising a sensor for the yaw angular velocity, a computing device for computing a body slip angle from the lateral acceleration, the yaw angular velocity and the actual speed of the vehicle, a threshold circuit for comparison of the body slip angle with a body slip-angle threshold value, a weighting circuit coupled to the output side of the threshold circuit, and which determines a correction value proportional to the determined body slip angle, a first summation point, in which a set speed of the vehicle is reduced from the actual speed of the vehicle by the correction value, a second summation point in which the actual speed of the vehicle is compared with the set speed of the vehicle in order to calculate a value of the control deviation, and a PD controller for adjusting the engine torque as a function of the value of the control deviation.
- 8. A method for controlling the cornering speed of a vehicle comprising the steps of determining a lateral acceleration and an actual speed of the vehicle, determining a yaw angular velocity of the vehicle, determining a body slip angle of the vehicle from the lateral acceleration, the yaw angular velocity and the actual speed of the vehicle, comparing the body slip angle with a body slip-angle threshold value, determining a vehicle set speed based at least in part on the comparison of the body slip angle with the body slip-angle threshold value, deriving a control deviation based on a difference between the set speed and the actual speed and, based on the control deviation, taking a corrective control action to control the speed of the vehicle.
- 13. A method for controlling the cornering speed of a vehicle comprising the steps of determining a body slip angle of the vehicle, comparing the body slip angle with a body slip-angle threshold value, and in response to a deviation of the body slip angle from the body slip-angle threshold value taking a corrective control action to the vehicle engine to control the speed of the vehicle.
- 18. In a vehicle having sensors for determining at least one of the vehicle'"'"'s speed, lateral acceleration and yaw angular velocity, an apparatus for controlling the cornering speed of the vehicle comprising a computing device for deriving a body slip angle, a threshold circuit for comparison of the body slip angle with a body slip-angle threshold value, a weighting circuit coupled to the output side of the threshold circuit, and which determines a correction value proportional to the body slip angle, a first summer, in which a set speed of the vehicle is reduced from the actual speed of the vehicle by the correction value, a second summer in which the actual speed of the vehicle is compared with the set speed of the vehicle in order to calculate a value of the control deviation, and means for performing a corrective action on the vehicle'"'"'s engine to control the vehicle'"'"'s speed.
Specification