Vehicle yaw control based on yaw rate estimate

A yaw control method utilizing differential braking of the vehicle wheels to impart a desired yaw moment on the vehicle, the vehicle having a pair of undriven wheels, the method comprising the steps of:

• measuring speeds of the undriven wheels of the vehicle;
• estimating a yaw rate of the vehicle based on a difference between the measured speeds;
• analyzing known vehicle parameters including the measured wheel speeds, a yaw error based on deviation of the estimated yaw rate from a desired yaw rate, the vehicle steering angle, and presence of driver braking to determine when the estimated yaw rate is valid and when the estimated yaw rate is invalid;
• differentially braking the vehicle wheels to impart a yaw moment based on the deviation of the estimated yaw rate from the desired yaw rate when the estimated yaw rate is determined to be valid;
• differentially braking the vehicle wheels to impart a yaw moment based on the desired yaw rate without regard to the estimated yaw rate when the estimated yaw rate is determined to be invalid;
• wherein the step of analyzing known vehicle parameters to determine when the estimated yaw rate is valid and when the estimated yaw rate is invalid includes the step of determining that the estimated yaw rate is invalid in response to an indication that driver braking is present;
• and
• wherein the indication that driver braking is present is maintained for a predefined period of time after driver braking is no longer present.

A yaw control method utilizing differential braking of the vehicle wheels to impart a desired yaw moment on the vehicle, the vehicle having a pair of undriven wheels, the method comprising the steps of:

• measuring speeds of the undriven wheels of the vehicle;
• estimating a yaw rate of the vehicle based on a difference between the measured speeds;
• analyzing known vehicle parameters including the measured wheel speeds, a yaw error based on deviation of the estimated yaw rate from a desired yaw rate, the vehicle steering angle, and presence of driver braking to determine when the estimated yaw rate is valid and when the estimated yaw rate is invalid;
• differentially braking the vehicle wheels to impart a yaw moment based on the deviation of the estimated yaw rate from the desired yaw rate when the estimated yaw rate is determined to be valid;
• differentially braking the vehicle wheels to impart a yaw moment based on the desired yaw rate without regard to the estimated yaw rate when the estimated yaw rate is determined to be invalid;
• and
• wherein the step of analyzing known vehicle parameters to determine when the estimated yaw rate is valid and when the estimated yaw rate is invalid includes the step of determining that the estimated yaw rate is invalid in response to an indication that the vehicle is in a spin-out condition.