BANK ANGLE DETECTING DEVICE FOR VEHICLE

• US 20120067122A1
• Filed: 08/16/2011
• Published: 03/22/2012
• Est. Priority Date: 09/22/2010
• Status: Active Grant

• Current Assignee: Kawasaki Jukogyo Kabushiki Kaisha (Kawasaki Heavy Industries Limited)
• Original Assignee: Kawasaki Jukogyo Kabushiki Kaisha (Kawasaki Heavy Industries Limited)
• Inventors: Sakamoto, Takuya, Harada, Yoshiteru
• Granted Patent: US 8,919,197 B2
• Time in Patent Office: Days
• US Class Current: 73/493
• CPC Class Codes: B60Q 1/12 due to steering position
• CPC Class Codes: B60Q 2300/112 Vehicle speed
• CPC Class Codes: B60Q 2300/134 Yaw
• CPC Class Codes: B60Q 2300/136 Roll
• CPC Class Codes: B60W 2300/36 Cycles; Motorcycles; Scooters
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/18 Roll
• CPC Class Codes: B60W 40/103 Side slip angle of vehicle body
• CPC Class Codes: B60W 40/112 Roll movement
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: B60Y 2200/12 Motorcycles, Trikes; Quads; Scooters
• CPC Class Codes: B62J 45/4151 for sensing lateral inclination of the cycle
• CPC Class Codes: B62J 6/023 responsive to the lean angle of the cycle, e.g. changing intensity or switching sub-lights when cornering

Abstract

A bank angle detecting device includes an angular velocity sensor for detecting a roll rate and a yaw rate of the vehicle, a roll rate estimating circuit for calculating an estimated roll rate, which is an angular velocity about a forward and rearward axis, on the basis of the roll rate, the yaw rate and a travelling speed, a bank angle estimator for calculating an estimated bank angle from the estimated roll rate, a straightforward travel determiner for determining a straightforward travelling condition on the basis of the estimated roll rate and an estimated yaw rate, a time-of-straight-forward-travel drift amount estimator for estimating a time-of-straight-forward drift amount from an output of the angular sensor in the event that the straightforward travel determiner determines a straightforward travel, and an angular velocity corrector for correcting the output of the angular velocity sensor with the time-of-straight-forward drift amount.

Claims

1. A bank angle detecting device for a vehicle, which comprises:

an angular velocity sensor for acquiring a detection value containing respective component of a roll rate, which is an angular velocity about a forward and rearward axis of the vehicle, and a yaw rate, which is an angular velocity about a vertical axis of the vehicle;

a roll rate estimator for calculating an estimated roll rate on the basis of the detection value of the angular velocity and a travelling speed of the vehicle;

a bank angle estimator for calculating an estimated bank angle of the vehicle from the estimated roll rate;

a straight forward travel determiner for determining a straight forward travelling condition of the vehicle during the travel of the vehicle on the basis of the estimated roll rate and a value associated with the estimated bank angle;

a time-of-straight-forward-travel drift amount estimator for estimating a sensor drift amount during the straight forward travel of the vehicle from an output of the angular velocity sensor in the event that the straight forward travel determiner determines the straight forward travelling condition; and

an angular velocity corrector for correcting the output of the angular velocity sensor with the sensor drift amount estimated by the time-of-straight-forward-travel drift amount estimator.

2. The bank angle detecting device for the vehicle as claimed in claim 1, in which the angular velocity sensor is so arranged as to incline at a predetermined angle of inclination about a leftward and rightward axis relative to the forward and rearward axis of the vehicle.

3. The bank angle detecting device for the vehicle as claimed in claim 1, in which the straight forward travel determiner determines the straight forward travelling condition in the event that a condition, in which the estimated roll rate is lower than a first predetermined determination value, continues for a first predetermined length of time and, also, a condition, in which the value associated with the estimated bank angle is lower than a second predetermined determination value, continues for a second predetermined length of time.

4. The bank angle detecting device for the vehicle as claimed in claim 1, in which the angular velocity corrector comprises a suppressing circuit for suppressing a change in amount of correction.

5. The bank angle detecting device for the vehicle as claimed in claim 1, further comprising a process suspending circuit operable to suspend the calculation of the drift amount during the straight forward travel, which is performed by the time-of-straight-forward-travel drift amount estimator, in the event that subsequent to determination of the straight forward travelling condition the estimated roll rate and the value associated with the estimated bank angle exceed respective predetermined values, but to resume such calculation in the event that they attain respective values lower than the predetermined values.

6. The bank angle detecting device for the vehicle as claimed in claim 5, further comprising a reset circuit operable to invalidate a calculation of the drift amount during the straight forward travel, which is performed by the time-of-straight-forward-travel drift amount estimator, in the event that such calculation fails to terminate within a predetermined length of time subsequent to the determination of the straight forward travelling condition.

7. The bank angle detecting device for the vehicle as claimed in claim 1, further comprising a standstill determiner for determining a standstill condition of the vehicle and a standstill time drift amount estimator for estimating a sensor drift amount from an output of the angular velocity sensor in the event that the standstill time determiner determines the standstill condition, and

wherein the angular velocity corrector corrects the output of the angular velocity sensor with the sensor drift amount estimated during the standstill condition.

8. The bank angle detecting device for the vehicle as claimed in claim 7, in which the estimated roll rate inputted to the standstill determiner is the one from which a change in frequency lower than a predetermined frequency is removed.

9. A motorcycle equipped with the bank angle detecting device as defined in claim 1.

10. A bank angle detecting method for a vehicle, which comprises:

a detecting step of acquiring a detection value containing roll rate and yaw rate components of the vehicle, by means of an angular velocity sensor;

a roll rate estimating step for calculating an estimated roll rate, which is an angular velocity about a forward and rearward axis, on the basis of the detection value, detected during the detecting step, and a travelling speed of the vehicle;

a bank angle estimating step of calculating an estimated bank angle of the vehicle from the estimated roll rate;

a straight forward travel determining step of determining a straight forward travelling condition of the vehicle during the travel of the vehicle on the basis of the estimated roll rate and a value associated with the estimated bank angle;

a time-of-straight-forward-travel drift amount estimating step of estimating a sensor drift amount during the straight forward travel of the vehicle from an output of the angular velocity sensor in the event that in the straight forward travel step the straight forward travelling condition is determined; and

an angular velocity correcting step of correcting the output of the angular velocity sensor with the sensor drift amount estimated in the time-of-straight-forward-travel drift amount estimating step.