Kinematic road gradient estimation
First Claim
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1. A vehicle comprising:
- a navigation system configured to generate output indicative of a measured vertical displacement of the vehicle;
a controller configured to;
generate output indicative of a kinematic road gradient estimation using an extended Kalman filter having a system input based on a longitudinal acceleration, and a system output based on a predicted vehicle speed, wherein the system output includes a predicted vertical displacement, andgenerate output indicative of a kinematic quality factor corresponding to an availability of the kinematic road gradient estimation;
estimate a first state indicative of an acceleration due to gravity based on a difference between the system output and a measured vehicle speed and a difference between the system output and the measured vertical displacement;
estimate a second state indicative of an acceleration due to a vehicle pitch angle based on a difference between the system output and the measured vehicle speed and a difference between the system output and the measured vertical displacement; and
calculate the kinematic road gradient estimation based on the first state and the second state.
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Abstract
A vehicle and a vehicle system are provided with a controller that is configured to generate output indicative of a kinematic road gradient estimation using an extended Kalman filter. The extended Kalman filter includes a system input based on a longitudinal acceleration and an acceleration offset, and a system output based on a predicted vehicle speed. The acceleration offset is based on at least one of a lateral velocity, a lateral offset, and a vehicle pitch angle. The controller is further configured to generate output indicative of a kinematic quality factor corresponding to an availability of the kinematic road gradient estimation.
40 Citations
16 Claims
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1. A vehicle comprising:
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a navigation system configured to generate output indicative of a measured vertical displacement of the vehicle; a controller configured to; generate output indicative of a kinematic road gradient estimation using an extended Kalman filter having a system input based on a longitudinal acceleration, and a system output based on a predicted vehicle speed, wherein the system output includes a predicted vertical displacement, and generate output indicative of a kinematic quality factor corresponding to an availability of the kinematic road gradient estimation; estimate a first state indicative of an acceleration due to gravity based on a difference between the system output and a measured vehicle speed and a difference between the system output and the measured vertical displacement; estimate a second state indicative of an acceleration due to a vehicle pitch angle based on a difference between the system output and the measured vehicle speed and a difference between the system output and the measured vertical displacement; and calculate the kinematic road gradient estimation based on the first state and the second state. - View Dependent Claims (2, 3, 4, 5)
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6. A vehicle system comprising:
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a controller configured to; calculate a vehicle pitch angle based on a suspension damping effect and a suspension stiffness value selected using a phase plane gain scheduling rule; and generate output indicating a kinematic road gradient estimation using an extended Kalman filter having a system input based on a longitudinal acceleration and an acceleration offset based on the vehicle pitch angle, and a system output based on a predicted vehicle speed. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for operating a vehicle based on an estimated kinematic road gradient comprising:
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receiving input indicative of a measured vertical displacement of the vehicle; generating output indicative of a kinematic road gradient estimation using an extended Kalman filter having a system input based on a longitudinal acceleration, and a system output based on a predicted vehicle speed, wherein the system output comprises a predicted vertical displacement; generating a kinematic quality factor that corresponds to an availability of the kinematic road gradient estimation; estimating a first state indicative of an acceleration due to gravity based on a difference between the system output and a measured vehicle speed and a difference between the system output and the measured vertical displacement; estimating a second state indicative of an acceleration due to a vehicle pitch angle based on a difference between the system output and the measured vehicle speed and a difference between the system output and the measured vertical displacement; and calculating the kinematic road gradient estimation based on the first state and the second state. - View Dependent Claims (16)
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Specification