ACCELERATION ESTIMATION DEVICE AND VEHICLE

• US 20070213899A1
• Filed: 03/05/2007
• Published: 09/13/2007
• Est. Priority Date: 03/08/2006
• Status: Active Grant

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: WATANABE, Hiroto, NISHIIKE, Yoshitaka, NISHIIKE, Yoshinobu
• Granted Patent: US 7,599,779 B2
• Time in Patent Office: Days
• US Class Current: 701/37
• CPC Class Codes: B60G 17/0164 mainly during accelerating or braking
• CPC Class Codes: B60G 17/01908 Acceleration or inclination sensors characterised by the use of gyroscopes B60G21/08
• CPC Class Codes: B60G 2300/12 Cycles; Motorcycles
• CPC Class Codes: B60G 2400/102 vertical
• CPC Class Codes: B60G 2400/106 longitudinal with regard to vehicle, e.g. braking
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/208 of wheel rotation
• CPC Class Codes: B60G 2600/1871 Optimal control; Kalman Filters
• CPC Class Codes: B60G 2800/702 Improving accuracy of a sensor signal
• CPC Class Codes: B60T 8/1706 for single-track vehicles, e.g. motorcycles
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: G01P 15/00 Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
• CPC Class Codes: G01P 15/18 in two or more dimensions

Abstract

In an acceleration estimation device for estimating acceleration of a vehicle, a Karman filter for constant speed estimates x-direction acceleration offset and z-direction acceleration offset when a motorcycle is stopped and is traveling at a constant speed. An offset corrector corrects an x-direction acceleration and a z-direction acceleration on the basis of an x-direction acceleration offset estimated value and a z-direction acceleration offset estimated value when the motorcycle is accelerated and decelerated. A Karman filter for acceleration/deceleration estimates the pitch angle of a vehicle body on the basis of a wheel speed and the corrected x-direction acceleration and z-direction acceleration when the motorcycle is accelerated and decelerated. An acceleration corrector obtains an X-direction acceleration and a Z-direction acceleration on the basis of the estimated pitch angle and the corrected x-direction acceleration and z-direction acceleration. A vehicle speed operation unit integrates over time the X-direction acceleration to calculate an X-direction speed.

Claims

1. An acceleration estimation device for estimating acceleration of a vehicle, comprising:

a first acceleration sensor arranged to detect an acceleration in a forward-and-backward direction of the vehicle;

a second acceleration sensor arranged to detect an acceleration in an up-and-down direction of the vehicle;

a pitch angle estimator arranged to estimate a pitch angle of the vehicle on the basis of a relationship between a detected value in the first acceleration sensor and a detected value in the second acceleration sensor; and

an acceleration calculator arranged to calculate an acceleration in a traveling direction of the vehicle that is substantially perpendicular to a direction of gravity on the basis of an estimated value of the pitch angle obtained by the pitch angle estimator, the detected value in the first acceleration sensor, and the detected value in the second acceleration sensor.

2. The acceleration estimation device according to claim 1, further comprising a speed calculator arranged to integrate a calculated value of the acceleration in the traveling direction obtained by the acceleration calculator to calculate a speed in the traveling direction.

3. The acceleration estimation device according to claim 1, wherein the pitch angle estimator includes:

a first Karman filter arranged to estimate the pitch angle of the vehicle using a relationship among the acceleration in the traveling direction of the vehicle that is substantially perpendicular to the direction of gravity, an acceleration in a vertical direction that is substantially parallel to the direction of gravity, the detected value in the first acceleration sensor, and the detected value in the second acceleration sensor, and the pitch angle of the vehicle.

4. The acceleration estimation device according to claim 1, further comprising:

an offset estimator arranged to estimate offset in the first acceleration sensor and offset in the second acceleration sensor when the vehicle is at a substantially constant speed; and

a corrector arranged to correct the detected value in the first acceleration sensor and the detected value in the second acceleration sensor on the basis of an estimated value of the offset in the first acceleration sensor and an estimated value of the offset in the second acceleration sensor that are obtained by the offset estimator when the vehicle is accelerated or decelerated;

wherein

the pitch angle estimator is arranged to estimate the pitch angle of the vehicle on the basis of the relationship between the detected value in the first acceleration sensor and the detected value in the second acceleration sensor that are corrected by the corrector when the vehicle is accelerated or decelerated.

5. The acceleration estimation device according to claim 4, further comprising a wheel speed detector arranged to detect a wheel speed of the vehicle, and the offset estimator includes:

a second Karman filter arranged to estimate the offset in the first acceleration sensor and the offset in the second acceleration sensor using a relationship among the acceleration in the traveling direction, the acceleration in the vertical direction, the detected value in the first acceleration sensor, the detected value in the second acceleration sensor, the speed in the traveling direction, the speed in the vertical direction, the speed of the vehicle obtained from the detected value in the wheel speed detector, and the pitch angle of the vehicle.

6. The acceleration estimation device according to claim 4, wherein:

the offset estimator is arranged to determine that the vehicle is in a substantially constant speed state when the rate of change in the wheel speed detected by the wheel speed detector is not more than a predetermined threshold value; and

the pitch angle estimator is arranged to determine that the vehicle is accelerated or decelerated when the rate of change in the wheel speed detected by the wheel speed detector is higher than the threshold value.

7. A vehicle comprising:

a vehicle body;

a wheel provided on the vehicle body;

an acceleration estimation device provided on the vehicle body; and

a controller;

wherein

the acceleration estimation device includes;

a first acceleration sensor on the vehicle and arranged to detect an acceleration in a forward-and-backward direction of the vehicle;

a second acceleration sensor on the vehicle and arranged to detect an acceleration in an up-and-down direction of the vehicle;

a pitch angle estimator arranged to estimate a pitch angle of the vehicle on the basis of a relationship between a detected value in the first acceleration sensor and a detected value in the second acceleration sensor; and

an acceleration calculator arranged to calculate an acceleration in a traveling direction of the vehicle that is substantially perpendicular to a direction of gravity on the basis of an estimated value of the pitch angle obtained by the pitch angle estimator, the detected value in the first acceleration sensor, and the detected value in the second acceleration sensor; and

the controller controls the rotation of the wheel on the basis of the acceleration in the traveling direction obtained by the acceleration estimation device.