JP2007271605A - Acceleration estimation device and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acceleration estimation device capable of estimating precisely an acceleration of a vehicle, and the vehicle provided therewith. <P>SOLUTION: In this acceleration estimation device, a Kalman filter 330 for a constant speed estimates an x-direction acceleration offset and a z-direction acceleration offset when a motorcycle 100 is stopped and travels at constant speed. An offset storage part 350 stores an x-direction acceleration offset estimated value and a z-direction acceleration offset estimated value. An offset correction part 360 corrects an x-direction acceleration and a z-direction acceleration, based on the x-direction acceleration offset estimated value and the z-direction acceleration offset estimated value when accelerated and decelerated. A Kalman filter 340 for acceleration/deceleration estimates a pitch angle of a vehicle body 1 when accelerated and decelerated. An acceleration correction part 370 obtains an x-direction acceleration and a z-direction acceleration, based on the estimated pitch angle. A vehicle speed computing part 380 calculates an x-direction speed by time integration of the x-direction acceleration. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an acceleration estimation device that estimates the acceleration of a vehicle and a vehicle including the same.

  The traveling speed of the vehicle can be calculated based on the rotational speed of the wheels. However, during rapid acceleration of the vehicle, the wheels may rotate while sliding against the road surface. Further, during sudden deceleration (during braking), there is a possibility of slipping on the road surface. In such a case, the vehicle speed calculated from the rotational speed of the wheels does not match the actual vehicle traveling speed.

  Therefore, the acceleration of the vehicle is detected using an acceleration sensor, and the speed of the vehicle is calculated by integrating the detected acceleration.

The acceleration sensor outputs acceleration as a voltage. Generally, there is an offset in the acceleration sensor. Here, the offset of the acceleration sensor is the difference between the nominal value of the output voltage of the acceleration sensor at the acceleration of 0 m / s ² and the actual output voltage value of the acceleration sensor in the unit of acceleration (m / s ² ). This is the converted value.

  Such an offset varies for each acceleration sensor. Patent Document 1 describes a vehicle longitudinal acceleration estimation device that calculates an estimated value of acceleration in the longitudinal direction by removing unnecessary components of an acceleration sensor that detects acceleration in the longitudinal direction.

  In the longitudinal acceleration estimation device disclosed in Patent Document 1, the change in the output voltage of the acceleration sensor is frequency-analyzed, the DC offset, the temperature drift, the road condition, the vehicle acceleration / deceleration, and the vehicle body pitching Classify into: And only the fluctuation component which has a frequency higher than a specific frequency is taken out from the detected value of the longitudinal acceleration by the acceleration sensor using the Kalman filter.

Thereby, the fluctuation component due to the DC offset having a low frequency and the fluctuation component due to the temperature drift are removed from the detected value of the longitudinal acceleration. As a result, an estimated value of the longitudinal acceleration that is not affected by changes with time and temperature is obtained.
JP-A-10-104259

  However, during rapid acceleration or deceleration, the vehicle body tilts due to pitching. That is, the front part of the vehicle body is lifted during rapid acceleration, and the front part of the vehicle body is depressed during rapid deceleration. Further, even when the vehicle travels at a constant speed, some pitching occurs in the vehicle body. As a result, a gravitational force acts on the acceleration sensor that detects the acceleration in the front-rear direction. As a result, the detection value of the acceleration sensor includes an offset and is affected by the force component of gravity.

  In the longitudinal acceleration estimation device of Patent Document 1, unnecessary components in a specific frequency band can be removed from the detection value of the acceleration sensor, but removing the influence of gravity component due to pitching other than the specific frequency band is not possible. Can not. Therefore, it is impossible to accurately estimate the acceleration in the longitudinal direction of the vehicle.

  The objective of this invention provides the acceleration estimation apparatus which can estimate the acceleration of a vehicle with high precision, and a vehicle provided with the same.

  (1) An acceleration estimation apparatus according to a first aspect of the present invention is an acceleration estimation apparatus that estimates the acceleration of a vehicle, the first acceleration sensor that is provided in the vehicle and detects the longitudinal acceleration of the vehicle, and the vehicle A second acceleration sensor for detecting the vertical acceleration of the vehicle, a wheel speed detector for detecting the wheel speed of the vehicle, and a detection value of the first acceleration sensor at a substantially constant speed of the vehicle, Offset estimation means for estimating the offset of the first acceleration sensor and the offset of the second acceleration sensor using the relationship between the detection value of the second acceleration sensor and the detection value of the wheel speed detector, and at the time of acceleration or deceleration of the vehicle Sometimes, the detected value of the first acceleration sensor based on the estimated value of the offset of the first acceleration sensor and the estimated value of the offset of the second acceleration sensor obtained by the offset estimating means Preliminary is obtained and a correction means for correcting the detected value of the second acceleration sensor.

Here, the substantially constant speed of the vehicle means when the vehicle is stopped and when the rate of change of the traveling speed of the vehicle is equal to or less than a predetermined threshold value. Threshold, for example in the range of -0.2 m / ^{s 2} of + 0.2m / ^{s 2.}

  In the acceleration estimation device, a first acceleration sensor and a second acceleration sensor are provided in the vehicle. The first acceleration sensor detects the vehicle longitudinal acceleration, and the second acceleration sensor detects the vehicle vertical acceleration. Further, the wheel speed of the vehicle is detected by the wheel speed detector.

  When the vehicle is at a substantially constant speed, the offset estimation means uses the relationship between the detection value of the first acceleration sensor, the detection value of the second acceleration sensor, and the detection value of the wheel speed detector to detect the offset of the first acceleration sensor and the first acceleration sensor. The offset of the second acceleration sensor is estimated. As a result, even when the detected value of the acceleration in the longitudinal direction and the detected value of the acceleration in the vertical direction are affected by gravity due to pitching, the acceleration is detected using the offset estimated in advance at the constant speed. The acceleration can be accurately detected.

  Here, the offset of the first acceleration sensor and the offset of the second acceleration sensor do not change in a short time.

  When the vehicle is accelerating or decelerating, the detected value of the first acceleration sensor based on the estimated value of the offset of the first acceleration sensor and the estimated value of the offset of the second acceleration sensor obtained when the vehicle is approximately constant speed, and The detection value of the second acceleration sensor is corrected by the correcting means. Thereby, the longitudinal acceleration and the vertical acceleration of the vehicle can be detected with high accuracy.

  (2) The offset estimation means includes an acceleration in the traveling direction of the vehicle orthogonal to the gravity direction, a vertical acceleration parallel to the gravity direction, a detected value of the first acceleration sensor, a detected value of the second acceleration sensor, and the traveling direction. The first acceleration sensor offset and the second acceleration sensor offset are estimated using the relationship between the vehicle speed, the vertical speed, the vehicle speed obtained from the detection value of the wheel speed detector, and the vehicle pitch angle. A first Kalman filter may be included.

  In this case, the offset of the first acceleration sensor and the offset of the second acceleration sensor are estimated by the first Kalman filter. As a result, even when gravity detection is caused by pitching at an arbitrary frequency on the detected value of the longitudinal acceleration and the detected value of the vertical acceleration, the offset of the first acceleration sensor and the offset of the second acceleration sensor are set. It becomes possible to estimate more accurately.

  In addition, the observation disturbance applied to the first acceleration sensor and the second acceleration sensor is removed by the first Kalman filter. This prevents the control system controlled based on the longitudinal and vertical accelerations of the vehicle from becoming unstable due to observation disturbance.

  (3) The acceleration estimating device includes a pitch angle estimating unit that estimates a pitch angle of the vehicle when the vehicle is accelerated or decelerated, a detection value of the first acceleration sensor corrected by the correcting unit, and a second acceleration sensor The apparatus may further include acceleration calculation means for calculating the acceleration in the traveling direction of the vehicle orthogonal to the gravity direction and the acceleration in the vertical direction parallel to the gravity direction based on the detected value and the pitch angle estimated by the pitch angle estimation means. .

  In this case, the pitch angle of the vehicle is estimated by the pitch angle estimation means, and is orthogonal to the direction of gravity based on the corrected detection value of the first acceleration sensor and the corrected detection value of the second acceleration sensor and the estimated pitch angle. The acceleration in the traveling direction and the acceleration in the vertical direction parallel to the direction of gravity are calculated. Thereby, even when the vehicle is accelerating or decelerating, the acceleration in the traveling direction of the vehicle can be detected with high accuracy.

  (4) The acceleration estimation device may further include speed calculation means for calculating the speed in the traveling direction by integrating the calculated value of the acceleration in the traveling direction obtained by the acceleration calculating means. In this case, the speed in the traveling direction of the vehicle can be detected with high accuracy.

  (5) The pitch angle estimation means is a relationship between the detection values of the first acceleration sensor and the second acceleration sensor corrected by the correction means, the acceleration in the traveling direction, the acceleration in the vertical direction, and the pitch angle of the vehicle. A second Kalman filter that estimates the pitch angle of the vehicle using may be included.

  In this case, the pitch angle of the vehicle is estimated by the second Kalman filter. This makes it possible to estimate the pitch angle of the vehicle more accurately even when the influence of gravity due to pitching at an arbitrary frequency is applied to the detected value of the longitudinal acceleration and the detected value of the acceleration in the vertical direction when the vehicle is accelerated or decelerated. It becomes possible to do.

  (6) The offset estimation means may determine that the vehicle is in a substantially constant speed state when the rate of change of the wheel speed detected by the wheel speed detector is equal to or less than a predetermined threshold value.

  In this case, when the rate of change of the wheel speed is equal to or less than the threshold value, it is determined that the vehicle is in a substantially constant speed state, and the offset of the first acceleration sensor and the offset of the second acceleration sensor are estimated by the offset estimation unit. The Thereby, even when the speed of the vehicle changes small, the offset of the first acceleration sensor and the offset of the second acceleration sensor can be detected with high accuracy.

  (7) A vehicle according to a second invention is a vehicle body, wheels provided on the vehicle body, an acceleration estimation device according to the first invention provided on the vehicle body, and a first acceleration corrected by the acceleration estimation device. Control means for controlling the rotation of the wheel based on at least one of the detection value of the sensor and the detection value of the second acceleration sensor.

  The offset of the first acceleration sensor and the offset of the second acceleration sensor are estimated by the acceleration estimation device when the vehicle is at substantially constant speed. Further, when the vehicle is accelerated or decelerated, the first acceleration estimation device uses the first estimated value of the offset of the first acceleration sensor and the estimated value of the offset of the second acceleration sensor obtained at the substantially constant speed of the vehicle. The detection value of the acceleration sensor and the detection value of the second acceleration sensor are corrected. Thereby, the longitudinal acceleration and the vertical acceleration of the vehicle can be detected with high accuracy.

  Then, the rotation of the wheel is controlled by the control means based on at least one of the detection value of the first acceleration sensor and the detection value of the second acceleration sensor corrected by the acceleration estimation device.

  According to the present invention, the offset of the first acceleration sensor and the second value are detected by the offset estimation means using the relationship between the detection value of the first acceleration sensor, the detection value of the second acceleration sensor, and the detection value of the wheel speed detector. The offset of the acceleration sensor is estimated. As a result, even when the detected value of the acceleration in the longitudinal direction and the detected value of the acceleration in the vertical direction are affected by gravity due to pitching, the acceleration is detected using the offset estimated in advance at the constant speed. The acceleration can be accurately detected.

  When the vehicle is accelerating or decelerating, the detected value of the first acceleration sensor based on the estimated value of the offset of the first acceleration sensor and the estimated value of the offset of the second acceleration sensor obtained when the vehicle is approximately constant speed, and The detection value of the second acceleration sensor is corrected by the correcting means. Thereby, the longitudinal acceleration and the vertical acceleration of the vehicle can be detected with high accuracy.

  In the following embodiments, an example in which the acceleration estimation device according to the present invention is applied to a motorcycle will be described.

(1) Basic concept of the present embodiment First, the relationship of acceleration during deceleration of a motorcycle including the acceleration detecting device according to the present embodiment will be described.

  FIG. 1 is a diagram showing the relationship of acceleration received by the acceleration sensor during deceleration.

  As shown in FIG. 1, when the motorcycle 100 is decelerated by the front wheel brake, the front suspension is contracted and the rear suspension is extended, and the motorcycle 100 tilts forward with respect to the traveling direction.

  A coordinate system fixed on the ground of the motorcycle 100 is a ground coordinate system, and a coordinate system fixed to an acceleration sensor attached to the motorcycle 100 is a sensor coordinate system.

  In the ground coordinate system, the traveling direction (direction perpendicular to gravity) of the motorcycle 100 on the horizontal ground 600 is defined as the X direction, and the vertical direction (direction of gravity) is defined as the Z direction. Therefore, regardless of the attitude of the motorcycle 100, the X direction and the Z direction of the ground coordinate system do not change.

  In the sensor coordinate system, the direction of the horizontal axis of the motorcycle 100 when the motorcycle 100 is in a horizontal state (the longitudinal direction of the vehicle body 1) is defined as the x direction, and the direction perpendicular to the horizontal axis of the motorcycle 100 (the vehicle body 1 Is defined as the z direction. Therefore, the x direction and the z direction of the sensor coordinate system are inclined with respect to the X direction and the Z direction of the ground coordinate system depending on the attitude of the motorcycle 100.

  Hereinafter, the X direction of the ground coordinate system is simply referred to as the X direction or the traveling direction, and the Z direction of the ground coordinate system is simply referred to as the Z direction or the vertical direction.

Acceleration G _x and z directions of the acceleration G _z in the x-direction in the sensor coordinate system from FIG. 1 is expressed by the following equation using the acceleration a _x and the Z-direction acceleration a _z in the X direction in the ground coordinate system.

G _x = a _x cos θ _p −a _z sin θ _p (1)
G _z = a _x sin θ _p + a _z cos θ _p (2)
In the above formulas (1) and (2), θ _p is the pitch angle of the vehicle body 1.

The motorcycle 100 according to the present embodiment is provided with an x-direction acceleration sensor for detecting the x-direction acceleration G _x of the vehicle body 1 and a z-direction acceleration sensor for detecting the z-direction acceleration G _z .

The x-direction acceleration sensor detects the x-direction acceleration G _x , the z-direction acceleration sensor detects the z-direction acceleration G _z , and obtains the pitch angle θ _p, thereby obtaining the X-direction acceleration in the ground coordinate system of the motorcycle 100. it can be measured acceleration _{a x} and the Z-direction acceleration _{a z.}

Generally, there is an offset in the acceleration sensor. Here, the offset of the acceleration sensor is the difference between the nominal value of the output voltage of the acceleration sensor at the acceleration of 0 m / s ² and the actual output voltage value of the acceleration sensor in the unit of acceleration (m / s ² ). This is the converted value.

  Hereinafter, the offset of the x direction acceleration sensor is referred to as an x direction acceleration offset, and the offset of the z direction acceleration sensor is referred to as a z direction acceleration offset.

  In the present embodiment, the x-direction acceleration offset and the z-direction acceleration offset are estimated using an extended Kalman filter, which will be described later, at approximately constant speed of the motorcycle 100.

  Here, the substantially constant speed includes when the motorcycle 100 is stopped, when the motorcycle 100 is traveling at a constant speed, and when the rate of change of the traveling speed of the motorcycle 100 is equal to or less than a predetermined threshold. In the following description, the time when the vehicle travels at a constant speed and the rate of change of the travel speed is equal to or less than a threshold value are simply referred to as when traveling at a constant speed.

Then, at the time of acceleration and deceleration of the motorcycle 100, and corrects the acceleration G _x and z directions of the acceleration G _z in the x direction based on the estimated value of the x-direction acceleration offset and the z-direction acceleration offset, x-direction acceleration G _x The pitch angle θ _p of the vehicle body 1 is estimated based on the correction value of the acceleration G _{z in} the z direction. Moreover, to calculate the acceleration of the acceleration and the Z-direction of the X-direction of the motorcycle 100 by using the estimated value of the pitch angle theta _p. Further, the speed in the X direction of the motorcycle 100 is calculated by integrating the acceleration in the X direction.

(2) Overall Configuration of Motorcycle According to the Present Embodiment FIG. 2 is a diagram showing an overall schematic configuration of the motorcycle 100 according to the present embodiment. The motorcycle 100 is equipped with an ABS (anti-lock brake system) which will be described later.

  As shown in FIG. 2, the front wheel 2 is attached to the front part of the vehicle body 1 of the motorcycle 100, and the rear wheel 3 is attached to the rear part of the vehicle body 1.

  A sensor rotor 4 that rotates together with the front wheel 2 is provided at the center of the front wheel 2. A front wheel speed sensor 5 for detecting the rotational speed of the front wheel 2 is attached to the sensor rotor 4. A front brake caliper 6 that contacts the brake disc of the front wheel 2 is provided to brake the front wheel 2.

  A sensor rotor 7 that rotates with the rear wheel 3 is provided at the center of the rear wheel 3. A rear wheel speed sensor 8 for detecting the rotational speed of the rear wheel 3 is attached to the sensor rotor 7. A rear brake caliper 9 that contacts the brake disk of the rear wheel 3 is provided to brake the rear wheel 3.

  A handle 11 is provided at the front upper portion of the vehicle body 1 so as to be able to swing left and right, and a front brake lever 12 and a warning lamp 13 are provided on the handle 11.

  A hydraulic unit 10 is provided at the center of the vehicle body 1. A rear brake pedal 14 is provided below the center of the vehicle body 1. An x-direction acceleration sensor 21 and a z-direction acceleration sensor 22 are attached to the center of gravity of the vehicle body 1. As the x-direction acceleration sensor 21 and the z-direction acceleration sensor 22, a biaxial acceleration sensor or a triaxial acceleration sensor used for inclination detection, airbag impact detection, hard disk fall detection, or the like can be used.

  An electronic control unit (hereinafter abbreviated as ECU) 30 and a fail safe relay 31 are provided at the rear of the vehicle body 1.

(3) Configuration of ABS FIG. 3 is a schematic diagram showing a hydraulic system and an electrical system of ABS.

  As shown in FIG. 3, a master cylinder 15 is connected to the front brake lever 12, and the master cylinder 15 is connected to the hydraulic unit 10. The master cylinder 15 is provided with a brake switch 17. A master cylinder 16 is connected to the rear brake pedal 14, and the master cylinder 16 is connected to the hydraulic unit 10. The master cylinder 16 is provided with a brake switch 18.

  When the driver operates the front brake lever 12, the master cylinder 15 increases the pressure of the hydraulic oil supplied from the hydraulic unit 10 to the front brake caliper 6. Thereby, the front brake caliper 6 is driven, and the front wheel 2 is braked. At this time, when the brake switch 17 is turned on, the front wheel brake signal Bf is given to the ECU 30.

  When the driver operates the rear brake pedal 14, the master cylinder 16 increases the pressure of the hydraulic oil supplied from the hydraulic unit 10 to the rear brake caliber 9. Thereby, the rear brake caliber 9 is driven and the rear wheel 3 is braked. At this time, when the brake switch 18 is turned on, the rear wheel brake signal Br is given to the ECU 30.

  A front wheel speed signal Rf indicating the rotational speed of the front wheel 2 is given to the ECU 30 from a front wheel speed sensor 5 provided in the sensor rotor 4 of the front wheel 2. Further, a rear wheel speed signal Rr indicating the rotational speed of the rear wheel 3 is given to the ECU 30 from a rear wheel speed sensor 8 provided on the sensor rotor 7 of the rear wheel 3. Hereinafter, the rotational speed of the front wheel 2 is referred to as a front wheel speed, and the rotational speed of the rear wheel 3 is referred to as a rear wheel speed.

  An x-direction acceleration signal Ax indicating the x-direction acceleration is supplied from the x-direction acceleration sensor 21 to the ECU 30. Further, a z-direction acceleration signal Az indicating the z-direction acceleration is given from the z-direction acceleration sensor 22 to the ECU 30.

  The ECU 30 outputs a motor drive signal MD for driving the hydraulic pump motor in the hydraulic unit 10 to the hydraulic unit 10 via the fail safe relay 31 in response to the front wheel brake signal Bf or the rear wheel brake signal Br.

  Further, the ECU 30 provides the front wheel speed signal Rf, the rear wheel speed signal Rr, the x direction acceleration signal Ax, and the z direction acceleration signal Az to the front wheel decompression signal FP and the rear wheel decompression signal RP as the fail-safe relay 31. And output to the hydraulic unit 10.

  The hydraulic unit 10 reduces the pressure of the hydraulic oil supplied to the front brake caliper 6 in response to the pressure reduction signal FP for the front wheels. Thereby, braking of the front wheel 2 by the front brake caliper 6 is loosened. In addition, the motorcycle 100 reduces the pressure of the hydraulic oil supplied to the rear brake caliper 9 in response to the rear wheel decompression signal RP. Thereby, braking of the rear wheel 3 by the rear brake caliper 9 is loosened.

  The fail-safe relay 31 switches the ABS operation of the hydraulic unit 10 to a normal braking operation when the ABS fails. When the ABS fails, the warning lamp 13 is turned on.

(4) Configuration of Vehicle Speed Estimation Unit FIG. 4 is a block diagram showing the configuration of the vehicle speed estimation unit.

  The acceleration estimation apparatus according to the present embodiment is used in vehicle speed estimation section 300 in FIG. The vehicle speed estimation unit 300 includes a speed selection unit 310, a filter selection unit 320, a constant speed Kalman filter 330, an acceleration / deceleration Kalman filter 340, an offset storage unit 350, an offset correction unit 360, an acceleration correction unit 370, and a vehicle speed calculation unit 380. Each component in the vehicle speed estimation unit 300 is realized by the functions of the ECU 30 and the program in FIGS. 2 and 3.

  The speed selector 310 is provided with a front wheel speed signal Rf and a rear wheel speed signal Rr from the front wheel speed sensor 5 and the rear wheel speed sensor 8, respectively, and is provided with an x direction acceleration signal Ax from the x direction acceleration sensor 21.

  Speed selection unit 310 selects front wheel speed signal Rf as the vehicle speed when motorcycle 100 is at substantially constant speed (when stopped and at constant speed). During acceleration / deceleration, the front wheel speed and the rear wheel speed are compared based on the front wheel speed signal Rf and the rear wheel speed signal Rr. During acceleration, the smaller of the front wheel speed and the rear wheel speed is selected as the vehicle speed, and during deceleration, The larger value of the front wheel speed and the rear wheel speed is selected as the vehicle speed. The determination of the substantially constant speed state or the acceleration / deceleration state is made based on the rate of change of the vehicle speed selected at the time of determination. Further, the vehicle speed selected by the speed selection unit 310 is output to the vehicle speed calculation unit 380.

  The constant speed Kalman filter 330 is supplied with the vehicle speed from the speed selection unit 310 and the x direction acceleration signal Ax and the z direction acceleration signal Az from the x direction acceleration sensor 21 and the z direction acceleration sensor 22, respectively. The constant-speed Kalman filter 330 estimates the x-direction acceleration offset and the z-direction acceleration offset by a method described later when the motorcycle 100 is at substantially constant speed (when stopped and at constant speed), and calculates the x-direction acceleration offset estimated value and z Obtain a direction acceleration offset estimate.

  The offset storage unit 350 stores the x-direction acceleration offset estimated value and the z-direction acceleration offset estimated value obtained by the constant velocity Kalman filter 330.

  The offset correction unit 360 is provided with the x-direction acceleration signal Ax and the z-direction acceleration signal Az from the x-direction acceleration sensor 21 and the z-direction acceleration sensor 22, respectively, and the x-direction acceleration offset estimated value and the z-direction acceleration from the offset storage unit 350. An offset estimate is given. When the motorcycle 100 is accelerated and decelerated, the offset correction unit 360 determines the x direction acceleration and the z direction based on the x direction acceleration offset estimated value, the z direction acceleration offset estimated value, the x direction acceleration signal Ax, and the z direction acceleration signal Az. Correct the acceleration.

  The acceleration / deceleration Kalman filter 340 determines the pitch angle of the vehicle body 1 based on the wheel speed given from the speed selection unit 310 and the x-direction acceleration and the z-direction acceleration corrected by the offset correction unit 360 when the motorcycle 100 is accelerated and decelerated. And an estimated pitch angle value is obtained.

  Information indicating the determination result of the substantially constant speed state or the acceleration / deceleration state is given to the filter selection unit 320 from the speed selection unit 310. Based on the information indicating the determination result, the filter selection unit 320 operates the constant speed Kalman filter 330 in the substantially constant speed state, operates the acceleration / deceleration Kalman filter 340 and operates the vehicle speed calculation unit 380 in the acceleration or deceleration state. Let

  The acceleration correction unit 370 corrects the x-direction acceleration and the z-direction acceleration corrected by the offset correction unit 360 based on the estimated pitch angle obtained by the acceleration / deceleration Kalman filter 340, thereby obtaining the X-direction acceleration and the Z-direction acceleration. obtain.

  The vehicle speed calculation unit 380 calculates the X direction speed (vehicle speed) by time-integrating the X direction acceleration obtained by the acceleration correction unit 370 with the vehicle speed obtained from the speed selection unit 310 immediately before the operation as an initial value, and indicates the vehicle speed. A vehicle speed signal VX is output.

(5) Operation of Vehicle Speed Estimation Unit FIG. 5 is a diagram for explaining the relationship between the estimation operation of the x-direction acceleration offset and the z-direction acceleration offset in the vehicle speed estimation unit 300 and the wheel speed change. The vertical axis in FIG. 5 represents offset and wheel speed, and the horizontal axis represents time. A thick solid line indicates a change in wheel speed, and a thin solid line indicates a change in the x-direction acceleration offset estimated value and the z-direction acceleration offset estimated value.

  The constant speed Kalman filter 330 performs an x-direction acceleration offset and a z-direction acceleration offset estimation operation when the motorcycle 100 is stopped and travels at a constant speed, and an x-direction acceleration offset estimated value and a z-direction acceleration offset estimate during acceleration and deceleration. The value is retained.

  FIG. 6 is a flowchart showing the operation of the vehicle speed estimation unit 300.

The filter selection unit 320 of the vehicle speed estimation unit 300 determines whether or not the change rate of the wheel speed selected by the speed selection unit 310 is greater than a predetermined threshold value (step S1). Here, the threshold value is set to, for example, −0.2 to +0.2 [m / s ² ].

  When the change rate of the wheel speed is equal to or less than a predetermined threshold value, the filter selection unit 320 regards the motorcycle 100 as stopped or traveling at a constant speed, and calculates the vehicle speed from the wheel speed (step S2). ). Here, the vehicle speed corresponds to an X-direction speed observation value described later.

  Next, the constant velocity Kalman filter 330 estimates the offset of the x-direction acceleration sensor 21 (x-direction acceleration offset) and the offset of the z-direction acceleration sensor 22 (z-direction acceleration offset) by a method to be described later, and x-direction acceleration offset. An estimated value and a z-direction acceleration offset estimated value are obtained (step S3). In this case, a Z-direction velocity observation value to be described later is set to 0, for example. Then, it returns to step S1.

  When the change rate of the wheel speed is larger than the predetermined threshold value in step S1, the filter selection unit 320 regards the motorcycle 100 as accelerating or decelerating, and the offset storage unit 350 determines the acceleration in the x direction. The previous value of the offset estimated value and the z-direction acceleration offset estimated value (value estimated in step S3) is stored (step S4).

  Next, the offset correction unit 360 uses the detected value of the x-direction acceleration sensor 21 and the z-direction acceleration sensor by a method described later based on the estimated x-direction acceleration offset value and the estimated z-direction acceleration offset value stored in the offset storage unit 350. Each of the detected values 22 is corrected (step S5).

  Next, the acceleration / deceleration Kalman filter 340 estimates the pitch angle of the vehicle body 1 by a method described later based on the detection value of the x-direction acceleration sensor 21 and the detection value of the z-direction acceleration sensor 22 corrected by the offset correction unit 360. A pitch angle estimated value is obtained (step S6).

  Next, the acceleration correction unit 370 uses the detection value of the x-direction acceleration sensor 21 corrected by the offset correction unit 360, the detection value of the z-direction acceleration sensor 22, and the estimated pitch angle by a method to be described later. X direction acceleration and Y direction acceleration are calculated by correcting the z direction acceleration (step S7).

  Furthermore, the vehicle speed calculation unit 380 calculates the vehicle speed by time-integrating the X-direction acceleration (step S8). Then, it returns to step S1.

(6) Configuration and Operation of ABS Signal Processing Unit FIG. 7 is a block diagram showing the configuration of the ABS signal processing unit.

  The ABS signal processing unit in FIG. 7 includes a vehicle speed estimation unit 300, a first signal generation unit 400, and a second signal generation unit 500. The ABS signal processing unit in FIG. 7 is realized by the functions of the ECU 30 and the program in FIGS. 2 and 3.

  First signal generation unit 400 includes an acceleration calculation unit 410, a slip determination unit 420, an acceleration determination unit 430, and a decompression signal generation unit 440. Second signal generation unit 500 includes an acceleration calculation unit 510, a slip determination unit 520, an acceleration determination unit 530, and a decompression signal generation unit 540.

  The slip determination unit 420 of the first signal generation unit 400 is given a front wheel speed signal Rf from the front wheel speed sensor 5 and a vehicle speed signal VX from the vehicle speed estimation unit 300. A front wheel speed signal Rf is given to the acceleration calculation unit 410 from the front wheel speed sensor 5.

  The slip determination unit 420 causes the front wheel 2 to slip based on whether or not the difference between the vehicle speed calculated based on the front wheel speed signal Rf and the vehicle speed indicated by the vehicle speed signal VX is greater than a predetermined reference value. It is determined whether or not.

  The acceleration calculation unit 410 calculates the acceleration of the front wheel 2 based on the front wheel speed signal Rf. The acceleration determination unit 430 determines whether or not the front wheel 2 has recovered from the slip state based on whether or not the acceleration calculated by the acceleration calculation unit 410 has changed from negative to positive.

  The decompression signal generator 440 gives the decompression signal FP to the hydraulic unit 10 in FIG. 3 when the slip determination unit 420 determines that the front wheel 2 is slipping, and the acceleration determination unit 430 recovers the front wheel 2 from the slip state. The pressure reduction signal FP is canceled when it is determined that the operation is being performed.

  The slip determination unit 520 of the second signal generation unit 500 is given a rear wheel speed signal Rr from the rear wheel speed sensor 8 and a vehicle speed signal VX from the vehicle speed estimation unit 300. The acceleration calculation unit 510 is provided with a rear wheel speed signal Rr from the rear wheel speed sensor 8.

  The slip determination unit 520 causes the rear wheel 3 to slip based on whether or not the difference between the vehicle speed calculated based on the rear wheel speed signal Rr and the vehicle speed indicated by the vehicle speed signal VX is greater than a predetermined reference value. It is determined whether or not.

  The acceleration calculation unit 510 calculates the acceleration of the rear wheel 3 based on the rear wheel speed signal Rr. The acceleration determination unit 530 determines whether or not the rear wheel 3 has recovered from the slip state based on whether or not the acceleration calculated by the acceleration calculation unit 510 has changed from negative to positive.

  The decompression signal generation unit 540 gives the decompression signal RP to the hydraulic unit 10 in FIG. 3 when the slip determination unit 520 determines that the rear wheel 3 is slipping, and the acceleration determination unit 530 causes the rear wheel 3 to slip. The decompression signal RP is canceled when it is determined that the recovery has occurred.

(7) Estimation of Offset by Constant Velocity Kalman Filter 330 Next, an estimation method of the x direction acceleration offset and the z direction acceleration offset by the constant velocity Kalman filter 330 will be described.

  Considering the x-direction acceleration offset, z-direction acceleration offset, observation noise, and process noise, the following equation of state is obtained. k is a step (discrete time).

  The observation equation is as follows.

  Table 1 shows the matrix elements of the above equations (3) and (4).

The X direction speed observation value V _obsx (k) of the above equation (4) is obtained from the front wheel speed signal Rf given from the front wheel speed sensor 5 of FIG. The Z-direction speed observation value V _obsz (k) is considered to be almost 0 at the time of stopping and traveling at a constant speed, and is set to 0.0 m / s here.

The x-direction acceleration observation value G _obsx (k) is obtained from the x-direction acceleration signal Ax from the x-direction acceleration sensor 21, and the z-direction acceleration observation value G _obsz (k) is obtained from the z-direction acceleration sensor 22. Is obtained.

  For observation noise and process noise, realistically and empirically valid values are set, respectively, and adjusted by simulation based on these values.

The left side of the above equation (3) is the state vector x _{k + 1} at step k + ₁ , and the state vector x _{k + 1} is expressed as the following equation.

The first term of the right side of the above equation (3) is the product of the state vector x _k in the coefficient vector A and step k, the coefficient vector A and the state vector x _k is expressed by the following equation.

The second term on the right side of the above equation (3) is the process noise vector w _k at step _k , and the process noise vector w _k is expressed by the following equation.

Third term of the right side of the above equation (3) is the external force vector u _k at step k, the external force vector u _k is expressed by the following equation.

The left side of the above equation (4) is an observation vector y _k at step k, and the observation vector y _k is expressed as the following equation.

The first term of the right side of the above equation (4) is the product of the state vector x _k in the coefficient vector B and the step k, the coefficient vector B is expressed by the following equation.

The second term on the right side of the above equation (4) is the observation noise vector v _k at step _k , and the observation noise vector v _k is expressed by the following equation.

  From the above equations (5) to (9), the above equation (3) is expressed as the following equation.

  From the above formulas (10) to (12) and (7), the above formula (4) is expressed as the following formula.

Here, the pitch angle θ _p is included in the state quantity (state vector element), and the x-direction acceleration offset and the z-direction acceleration offset are estimated by sequential calculation using an extended Kalman filter as follows.

The state vector z _k in step k including the pitch angle θ _p is expressed as follows.

The subscript T represents a transposed matrix. Further, the function f _k (z _k ) is expressed as the following equation.

In the above equation (14), the coefficient vector F _k is expressed as the following equation.

The constant A _ax is 0, for example, and the constant A _θp is 1, for example. Here, the estimated value of the state vector _{z k} at step k _{z Ek |} a _k, the estimate of the state vector _{z k} at step k-1 _{z Ek |} a _k-1, the estimation of the state vector _{z k + 1} in step k If the value is _{zEk + 1 | k} , the filter equation is as follows.

In the above equation (16), K _k is the Kalman gain, and the observation vector y _k is represented by the above equation (10). The function h _k (z _{Ek | k−1} ) will be described later.

The Kalman gain K _k is expressed as follows.

In the above equation (18), Σ _{k | k−1} is the covariance matrix of the estimation error of the state vector z _k in step k−1, and Σ _vk is the covariance matrix of the observation noise vector v _k . The matrix _Hk will be described later.

The covariance matrix Σ _{k | k} of the estimation error of the state vector z _k is expressed as follows:

  The error covariance matrix equation is expressed as:

The matrix _Gk will be described later. The matrix H _k in the above equations (18) and (19) is expressed as the following equation.

In addition, the function h _k (z _{Ek | k−1} ) in the above equation (16) is expressed as the following equation.

In the above equation (22), x _{Ek | k−1} is an estimated value of the state vector x _k in step k−1. Θ _{pEk | k−1} is an estimated value of the pitch angle θ _p (k) at step k−1. The matrix C _k is expressed as follows:

The matrix G _k in the above equation (20) is expressed as the following equation.

  In the above equation (24), I is a unit matrix.

With the extended Kalman filter, the pitch angle θ _p (k) can be estimated together with the x-direction acceleration offset ε _offx (k) and the z-direction acceleration offset ε _offz (k) when the motorcycle 100 is stopped and traveling at a constant speed. .

(8) Simulation of constant velocity Kalman filter 330 Here, simulation of the constant velocity Kalman filter 330 was performed, and the x-direction acceleration offset and the z-direction acceleration offset were estimated.

  FIG. 8 is a diagram showing the relationship between the true value of the acceleration offset and the estimation error of the acceleration offset.

  The horizontal axis in FIG. 8 represents the true value of the x-direction acceleration offset and the z-direction acceleration offset, and the vertical axis represents the acceleration offset estimation error. The estimation error of the acceleration offset is the difference between the estimated value of the x-direction acceleration offset and the true value of the x-direction acceleration offset, and the difference between the estimated value of the z-direction acceleration offset and the true value of the z-direction acceleration offset.

In FIG. 8, the estimation error of the z-direction acceleration offset is indicated by white circles, and the estimation error of the x-direction acceleration offset is indicated by black triangles. As shown in FIG. 8, the estimation error of the x-direction acceleration offset was within 0.06 m / s ² , and the estimation error of the z-direction acceleration offset was within 0.001 m / s ² .

  FIG. 9 is a diagram showing a temporal change in the estimated value of the acceleration offset in the estimation process of the acceleration offset.

  The horizontal axis in FIG. 9 represents time, and the vertical axis represents acceleration offset. In FIG. 9, the true value of the z-direction acceleration offset is indicated by a thin solid line, the estimated value of the z-direction acceleration offset is indicated by a thick solid line, the true value of the x-direction acceleration offset is indicated by a thin dotted line, and the estimated value of the x-direction acceleration offset Is indicated by a thick dotted line.

  As shown in FIG. 9, the estimated value of the x-direction acceleration offset and the estimated value of the z-direction acceleration offset both converge completely in 2 seconds. From this, it is possible to estimate the x-direction acceleration offset and the z-direction acceleration offset if a constant velocity state of 2 seconds or more exists.

(9) Pitch Angle Estimation Using Acceleration / Deceleration Kalman Filter 340 Next, a pitch angle estimation method using the acceleration / deceleration Kalman filter 340 will be described.

  Considering the observation noise and process noise, the following equation of state is obtained. k is a step (discrete time).

  The observation equation is as follows.

  Table 2 shows the matrix elements of the above equations (25) and (26).

Here, the x-direction acceleration correction value G _Aobx (k) is the x-direction acceleration corrected by the offset correction unit 360 of FIG. 4, and the x-direction acceleration offset ε _offx (k) from the x-direction acceleration observation value G _obsx (k). ) Is subtracted. Further, z direction acceleration correction value _{G Aobz} (k) is the z-direction acceleration corrected by the offset correction unit 360 of FIG. 4, z direction acceleration observed value _{G obz} (k) from the z-direction acceleration offset _ε offz (k) Is a value obtained by subtracting.

  For observation noise and process noise, realistically and empirically valid values are set, respectively, and adjusted by simulation based on these values.

The left side of the above equation (25) is the state vector x _{k + 1} at step k + ₁ , and the state vector x _{k + 1} is expressed as the following equation.

The first term of the right side of the above equation (25) is the product of the state vector x _k in the coefficient vector A and step k, the coefficient vector A and the state vector x _k is expressed by the following equation.

The second term on the right side of the above equation (25) is the process noise vector w _k at step _k , and the process noise vector w _k is expressed by the following equation.

The left side of the above equation (26) is the observation vector y _k at step k, and the observation vector y _k is expressed as the following equation.

The first term of the right side of the above equation (26) is the product of the state vector x _k in the coefficient vector B and the step k, the coefficient vector B is expressed by the following equation.

The second term of the above equation (26) is the observation noise vector v _k at step _k , and the observation noise vector v _k is expressed by the following equation.

  From the above equations (27) to (30), the above equation (25) is expressed as the following equation.

  From the above equations (31) to (33), (29), the above equation (26) is expressed as the following equation.

Here, the pitch angle θ _p is estimated by using the extended Kalman filter as follows by including the pitch angle θ _p in the state quantity (state vector element).

The state vector z _k in step k including the pitch angle θ _p is expressed as follows.

The subscript T represents a transposed matrix. Further, the function f _k (z _k ) is expressed as the following equation.

In the above equation (35), the coefficient vector F _k is expressed as the following equation.

The constant A _ax is 0, for example, and the constant A _θp is 1, for example. Here, the estimated value of the state vector _{z k} at step k _{z Ek |} a _k, the estimate of the state vector _{z k} at step k-1 _{z Ek |} a _k-1, the estimation of the state vector _{z k + 1} in step K If the value is _{zEk + 1 | k} , the filter equation is as follows.

In the above equation (37), K _k is the Kalman gain, and the observation vector y _k is represented by the above equation (31). The function h _k (z _{Ek | k−1} ) will be described later.

The Kalman gain K _k is expressed as follows.

In the above equation (39), Σ _{k | k−1} is the covariance matrix of the estimation error of the state vector z _k in step k−1, and Σ _vk is the covariance matrix of the observation noise vector v _k . The matrix _Hk will be described later.

The covariance matrix Σ _{k | k} of the estimation error of the state vector z _k is expressed as follows:

  The error covariance matrix equation is expressed as:

The matrix _Gk will be described later. The matrix H _k is expressed as follows:

In addition, the function h _k (z _{Ek | k−1} ) in the above equation (37) is expressed as the following equation.

In the above equation (43), x _{Ek | k−1} is an estimated value of the state vector x _k in step k−1. Θ _{pEk | k−1} is an estimated value of the pitch angle θ _p (k) at step k−1. The matrix C _k is expressed as follows:

The matrix G _k in the above equation (41) is expressed as the following equation.

  In the above equation (45), I is a unit matrix.

The pitch angle θ _p (k) at the time of acceleration and deceleration of the motorcycle 100 can be estimated by the extended Kalman filter.

(10) Correction of Acceleration by Acceleration Correction Unit 370 The acceleration correction unit 370 corrects the x-direction acceleration and the z-direction acceleration by the following equations using the estimated pitch angle value obtained by the acceleration / deceleration Kalman filter 340. Thereby, an X direction acceleration estimated value and a Z direction acceleration estimated value are obtained.

  Table 3 shows the elements of the matrix of the above equation (46).

Here, the x-direction acceleration correction value G _Aobx (k) is the x-direction acceleration corrected by the offset correction unit 360 of FIG. 4, and the x-direction acceleration offset ε _offx (k) from the x-direction acceleration observation value G _obsx (k). ) Is subtracted. Further, z direction acceleration correction value _{G Aobz} (k) is the z-direction acceleration corrected by the offset correction unit 360 of FIG. 4, z direction acceleration observed value _{G obz} (k) from the z-direction acceleration offset _ε offz (k) Is a value obtained by subtracting.

The X-direction acceleration estimated value a _Ex and the Z-direction acceleration estimated value a _Ez at the time of acceleration and deceleration of the motorcycle 100 can be calculated by the above equation (46).

(11) Simulation of Acceleration / Deceleration Kalman Filter 340 Here, the acceleration / deceleration Kalman filter 340 and the acceleration correction unit 370 were simulated, and the X-direction acceleration and the Z-direction acceleration were estimated.

  FIG. 10 is a diagram showing the estimation result of the X-direction acceleration. The horizontal axis in FIG. 10 represents time, and the vertical axis represents acceleration.

In FIG. 10, the true value of the X-direction acceleration is indicated by a dotted line, and the estimated X-direction acceleration value a _Ex obtained by the acceleration correction unit 370 using the estimated pitch angle θ _Ep obtained by the acceleration / deceleration Kalman filter 340 is indicated by a solid line. The x-direction acceleration correction value G _Aobx (k) obtained by the offset correction unit 360 is indicated by a one-dot chain line. The x-direction acceleration correction value G _Aobx (k) is affected by the pitch angle, although the influence of the x-direction acceleration offset is removed.

As shown in FIG. 10, the X-direction acceleration estimated value a _Ex is closer to the true value of the X-direction acceleration than the x-direction acceleration correction value G _Aobx (k).

Furthermore, the vehicle speed was estimated by integrating the true value of the X direction acceleration, the X direction acceleration estimated value a _Ex, and the x direction acceleration correction value G _Aobx (k) over time.

  FIG. 11 is a diagram showing the estimation result of the vehicle speed. The horizontal axis in FIG. 11 represents time, and the vertical axis represents the estimated vehicle speed.

In FIG. 11, the vehicle speed calculated using the true value of the X direction acceleration (X direction vehicle speed true value) is indicated by a dotted line, and the X direction vehicle speed estimated value calculated using the X direction acceleration estimated value a _Ex is indicated by a solid line. The x-direction vehicle speed estimation value calculated using the x-direction acceleration correction value G _Aobx (k) is indicated by a one-dot chain line.

As shown in FIG. 11, the X-direction vehicle speed estimated value calculated using the X-direction acceleration estimated value a _Ex is compared with the x-direction vehicle speed estimated value calculated using the x-direction acceleration correction value G _Aobx (k). The X-direction vehicle speed is close to the true value.

(12) Effects of the present embodiment (12-1)
In the motorcycle 100 according to the present embodiment, the offset of the x-direction acceleration sensor 21 and the offset of the z-direction acceleration sensor 22 are highly accurate by the constant-speed Kalman filter 330 of the vehicle speed estimation unit 300 when stopped and when traveling at a constant speed. Presumed. Thereby, even when the detection value of the x-direction acceleration sensor 21 and the detection value of the z-direction acceleration sensor 22 are affected by gravity due to pitching at an arbitrary frequency, the offset of the x-direction acceleration sensor 21 and the z-direction acceleration sensor 22 It is possible to accurately estimate the offset.

(12-2)
In addition, the observation disturbance applied to the x-direction acceleration sensor 21 and the z-direction acceleration sensor 22 is removed by the constant velocity Kalman filter 330. This prevents the ABS controlled by the vehicle speed in the X direction obtained by the vehicle speed estimation unit 300 from becoming unstable due to observation disturbance.

(12-3)
Further, the estimated offset value of the x-direction acceleration sensor 21 and the estimated offset value of the z-direction acceleration sensor 22 obtained when the motorcycle 100 is stopped or traveling at a constant speed are stored in the offset storage unit 350, and During acceleration or deceleration, the detected value of the x-direction acceleration sensor 21 and the acceleration in the z-direction are based on the estimated offset value of the x-direction acceleration sensor 21 and the estimated offset value of the z-direction acceleration sensor 22 stored in the offset storage unit 350. The detection value of the sensor 22 is corrected by the offset correction unit 360. Thereby, the x-direction acceleration and the z-direction acceleration of the motorcycle 100 can be detected with high accuracy.

(12-4)
Further, when the motorcycle 100 is accelerated or decelerated, the pitch angle of the vehicle body 1 is estimated by the acceleration / deceleration Kalman filter 340. Thereby, it is possible to estimate the pitch angle by pitching at an arbitrary frequency with low cost and high accuracy without using an expensive gyro sensor.

(12-5)
Further, the X direction acceleration and the Y direction acceleration of the motorcycle 100 are calculated by the acceleration correction unit 370 based on the estimated value of the pitch angle, the detection value of the x direction acceleration sensor 21, and the detection value of the z direction acceleration sensor 22. Thereby, the X direction acceleration of the motorcycle 100 can be detected with high accuracy.

  Further, the vehicle speed calculation unit 380 can obtain the vehicle speed in the X direction from the acceleration in the X direction with high accuracy. Therefore, when both the front wheel 2 and the rear wheel 3 are braked, it is possible to detect the slipping of the front wheel 2 and the rear wheel 3 and to detect the vehicle speed with high accuracy.

  Further, when both the front wheel 2 and the rear wheel 3 are slipping, such as when the front wheel 2 is braked while the rear wheel 3 is being driven, the vehicle body 1 is determined from the wheel speeds of the front wheel 2 and the rear wheel 3. The center of gravity speed cannot be obtained. Even in such a case, it is possible to detect the slip of the front wheel 2 and the rear wheel 3 using the vehicle speed estimation unit 300 of the present embodiment, and it is possible to detect the vehicle speed with high accuracy.

(13) Other Embodiments (a) In the above embodiment, the case where the acceleration estimation device of the present invention is applied to ABS has been described. However, the present invention is not limited to this, and the acceleration estimation device of the present invention is used. The present invention may be applied to other brake control systems, may be applied to traction control systems, and may be applied to cruise control systems. The traction control system refers to a system that obtains an optimum driving force when turning, starting, or accelerating by controlling driving force of driving wheels or output and braking force of an engine. The cruise control system refers to a system that automatically controls the vehicle speed at a long distance or for a long time.

  Moreover, the acceleration estimation apparatus of the present invention can also be applied to drivability control using an electronic throttle. Drivability control refers to control for obtaining comfortable driving performance. When the acceleration estimation device of the present invention is applied to drivability control, the error of the acceleration sensor can be reduced, so that the comfortable driving performance can be controlled with high accuracy. As a result, it is possible to provide smooth acceleration that does not cause the driver to feel changes and fluctuations in acceleration.

  Furthermore, the acceleration estimation device of the present invention can be used for estimating the acceleration of a vehicle when a GPS (Global Positioning System) signal cannot be received in the navigation system.

  (B) In the above embodiment, each component in the vehicle speed estimation unit 300 is realized by the functions of the ECU 30 and the program. However, the present invention is not limited to this, and some of the components in the vehicle speed estimation unit 300 or All may be realized by hardware such as an electronic circuit.

  (C) In the above embodiment, the offset estimation unit is configured by the constant velocity Kalman filter 330 including an extended Kalman filter. However, the present invention is not limited to this, and the offset estimation unit may be realized by another adaptive filtering method. For example, an LMS (least mean square) adaptive filter or H∞ filtering may be used.

  (D) In the above embodiment, the pitch angle estimation unit is configured by the acceleration / deceleration Kalman filter 340 including an extended Kalman filter. However, the present invention is not limited to this, and the pitch angle estimation unit may be realized by another adaptive filtering method. Good. For example, an LMS adaptive filter or H∞ filtering may be used.

  (E) The vehicle speed estimation unit 300 of the above-described embodiment is not limited to the motorcycle 100 but can be applied to various vehicles such as a motorcycle, a four-wheeled vehicle, and a three-wheeled vehicle.

(14) Correspondence between each component of claim and each part of embodiment Hereinafter, an example of a correspondence between each component of the claim and each part of the embodiment will be described, but the present invention is limited to the following example. Not.

  In the above embodiment, the motorcycle 100 is an example of a vehicle, the x-direction acceleration sensor 21 is an example of a first acceleration sensor, the z-direction acceleration sensor 22 is an example of a second acceleration sensor, and the front wheel speed. The sensor 5 is an example of a wheel speed detector, the constant speed Kalman filter 330 is an example of an offset estimation unit or a first Kalman filter, and the offset correction unit 360 is an example of a correction unit.

  The acceleration / deceleration Kalman filter 340 is an example of a pitch angle estimation unit or a second Kalman filter, the acceleration correction unit 370 is an example of an acceleration calculation unit, and the vehicle speed estimation unit 300 is an example of a speed calculation unit.

  Furthermore, the front wheel 2 or the rear wheel 3 is an example of a wheel, and the first signal generator 400 and the second signal generator 500 are examples of control means.

  The present invention can be used for various vehicles such as motorcycles, four-wheeled vehicles, and three-wheeled vehicles.

It is a figure which shows the relationship of the acceleration which an acceleration sensor receives at the time of deceleration. 1 is a diagram showing an overall schematic configuration of a motorcycle according to the present embodiment. It is a schematic diagram which shows the hydraulic system and electric system of ABS. It is a block diagram which shows the structure of a vehicle speed estimation part. It is a figure for demonstrating the relationship between the estimation operation | movement of the x direction acceleration offset and z direction acceleration offset in a vehicle speed estimation part, and the change rate of a wheel speed. It is a flowchart which shows operation | movement of a vehicle speed estimation part. It is a block diagram which shows the structure of an ABS signal processing part. It is a figure which shows the relationship between the true value of acceleration offset, and the estimation error of acceleration offset. It is a figure which shows the time change of the estimated value of the acceleration offset in the estimation process of an acceleration offset. It is a figure which shows the estimation result of a X direction acceleration. It is a figure which shows the estimation result of a vehicle speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2 Front wheel 3 Rear wheel 4 Sensor rotor 5 Front wheel speed sensor 6 Front brake caliper 7 Sensor rotor 8 Rear wheel speed sensor 9 Rear brake caliper 10 Hydraulic unit 11 Handle 12 Front brake lever 13 Warning light 14 Rear brake pedal 15, 16 Master Cylinder 17, 18 Brake switch 21 x direction acceleration sensor 22 z direction acceleration sensor 30 ECU
31 Failsafe Relay 100 Motorcycle 300 Vehicle Speed Estimation Unit 310 Speed Selection Unit 320 Filter Selection Unit 330 Constant Speed Kalman Filter 340 Acceleration / Deceleration Kalman Filter 350 Offset Storage Unit 360 Offset Correction Unit 370 Acceleration Correction Unit 380 Vehicle Speed Calculation Unit 400 First Signal Generation unit 500 Second signal generation unit 410, 510 Acceleration calculation unit 420, 520 Slip determination unit 430, 530 Acceleration determination unit 440, 540 Decompression signal generation unit 600 Ground a _x X direction acceleration a _z Z direction acceleration G _x x direction acceleration G _z z direction acceleration θ _p pitch angle Ax x direction acceleration signal Az z direction acceleration signal Bf front wheel brake signal Br rear wheel brake signal FP, RP decompression signal MD motor drive signal Rf front wheel speed signal Rr rear wheel speed Signal X vehicle speed signal

Claims (7)

An acceleration estimation device for estimating the acceleration of a vehicle,
A first acceleration sensor provided in the vehicle for detecting acceleration in the longitudinal direction of the vehicle;
A second acceleration sensor provided in the vehicle for detecting an acceleration in a vertical direction of the vehicle;
A wheel speed detector for detecting a wheel speed of the vehicle;
The offset of the first acceleration sensor using the relationship between the detection value of the first acceleration sensor, the detection value of the second acceleration sensor, and the detection value of the wheel speed detector when the vehicle is at substantially constant speed. Offset estimating means for estimating an offset of the second acceleration sensor;
Based on the estimated value of the offset of the first acceleration sensor and the estimated value of the offset of the second acceleration sensor obtained by the offset estimating means during acceleration or deceleration of the vehicle, the first acceleration sensor An acceleration estimation apparatus comprising: a correction unit that corrects a detection value and a detection value of the second acceleration sensor. The offset estimation means includes
The acceleration in the traveling direction of the vehicle orthogonal to the direction of gravity, the acceleration in the vertical direction parallel to the direction of gravity, the detected value of the first acceleration sensor, the detected value of the second acceleration sensor, the speed in the traveling direction, Using the relationship between the speed in the vertical direction, the speed of the vehicle obtained from the detection value of the wheel speed detector, and the pitch angle of the vehicle, the offset of the first acceleration sensor and the offset of the second acceleration sensor The acceleration estimation apparatus according to claim 1, further comprising a first Kalman filter for estimating Pitch angle estimating means for estimating a pitch angle of the vehicle at the time of acceleration or deceleration of the vehicle;
Progress of the vehicle orthogonal to the direction of gravity based on the detected value of the first acceleration sensor and the detected value of the second acceleration sensor corrected by the correcting means and the pitch angle estimated by the pitch angle estimating means. 3. The acceleration estimation apparatus according to claim 1, further comprising acceleration calculation means for calculating a direction acceleration and a vertical acceleration parallel to the direction of gravity. 4. The acceleration estimation apparatus according to claim 3, further comprising speed calculating means for calculating the speed in the traveling direction by integrating the calculated value of acceleration in the traveling direction obtained by the acceleration calculating means. The pitch angle estimating means includes
Using the detected value of the first acceleration sensor and the detected value of the second acceleration sensor corrected by the correcting means, the acceleration in the traveling direction, the acceleration in the vertical direction, and the pitch angle of the vehicle The acceleration estimation apparatus according to claim 3, further comprising a second Kalman filter that estimates a pitch angle of the vehicle. The offset estimation means determines that the vehicle is in a substantially constant speed state when a rate of change in wheel speed detected by the wheel speed detector is equal to or less than a predetermined threshold value. The acceleration estimation apparatus in any one of Claims 1-5. The car body,
Wheels provided on the vehicle body;
The acceleration estimation device according to any one of claims 1 to 6, provided on the vehicle body,
A vehicle comprising: control means for controlling rotation of the wheel based on at least one of the detection value of the first acceleration sensor and the detection value of the second acceleration sensor corrected by the acceleration estimation device.

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