JP6679348B2 - Vehicle front-rear speed estimation device - Google Patents

Description

  The present invention relates to a vehicle front-rear speed estimation device, and more particularly to a vehicle front-rear speed estimation device in which driving wheels and steered wheels are arranged at different positions.

  In order to prevent the wheels from slipping, for example to perform traction control, the vehicle speed at the position of the drive wheels is required. In the case of a vehicle in which the drive wheels and the steered wheels are arranged at different positions, the drive wheels and the vehicle are arranged such that the plane orthogonal to the rotation axis of the drive wheels and the front-back direction of the vehicle body are parallel to each other. Therefore, the vehicle speed at the position of the drive wheels can be calculated from the vehicle front-rear speed and the yaw rate. The front-rear speed of the vehicle can be accurately estimated by using the wheel rotation speed of the driven wheels. Here, when the sideslip angle occurring in the vehicle is large, it is necessary to correct the influence of the sideslip angle of the vehicle.

For example, a technique has been proposed in which the sideslip angular velocity is obtained using the tangential acceleration and the normal direction acceleration of the turning circle, and the yaw rate, and the sideslip angle is estimated by integrating the sideslip angular velocity (Patent Document 1). The longitudinal velocity of the vehicle during turning is estimated by using the estimated sideslip angle.
With respect to the estimation of the sideslip angle, for example, a technique has been proposed in which the sideslip angle is estimated from a vehicle model in which the steering wheel angle and the vehicle speed are input variables (Patent Document 2). The longitudinal speed of the vehicle body can be estimated from the estimated sideslip angle and the rotational speed of the wheels.

JP, 10-175537, A JP-A-62-83247

  In Patent Document 1, the sideslip angular velocity is obtained using the tangential direction acceleration and the normal direction acceleration of the turning circle, and the yaw rate, and the sideslip angle is estimated by integrating the sideslip angular velocity. However, an error (drift) is likely to be accumulated in the integral calculation. Therefore, if the integration calculation for a long time is performed, the estimation accuracy of the sideslip angle is likely to be deteriorated, so that the longitudinal speed of the vehicle may not be accurately estimated.

  In Patent Document 2, the sideslip angle is estimated from the vehicle model. As shown in FIG. 6, in a region where the lateral force (cornering force) that can be generated by the tire has a linear relationship with the sideslip angle that occurs in the tire (hereinafter, referred to as “the linear region of the tire”), it is good. It is possible to estimate the sideslip angle with high accuracy, but in the region where the lateral force that can be generated by the tire is in a non-linear relationship with the sideslip angle that occurs in the tire (hereinafter referred to as "the nonlinear region of the tire") Accuracy deteriorates. In this case, the longitudinal speed of the vehicle cannot be accurately estimated.

  As another method, it is possible to estimate the longitudinal velocity of the vehicle from the integral calculation of the longitudinal acceleration. However, an error (drift) is likely to be accumulated in the integral calculation, and the longitudinal speed of the vehicle cannot be accurately estimated.

  An object of the present invention is to provide a vehicle front-rear speed estimation device capable of accurately estimating the front-rear speed of a vehicle regardless of the traveling state of the vehicle in a vehicle including steered wheels that are driven wheels and drive wheels. It is to be.

A front-rear speed estimating device for a vehicle according to the present invention is a front-rear speed estimating device 10 for estimating a front-rear speed in a vehicle including left and right steered wheels 3 which are driven wheels and left and right driving wheels 2.
A pair of wheel rotation speed measuring means 14 for measuring the wheel rotation speeds of the left and right steered wheels 3, respectively;
Steering wheel angle measuring means 15 for measuring the steering wheel angle of the vehicle,
Yaw rate measuring means 16 for measuring the yaw rate of the vehicle,
Longitudinal acceleration measuring means 17 for measuring longitudinal acceleration of the vehicle,
A traveling state determination means 26 for determining whether or not the traveling state of the vehicle is a predetermined limit traveling state,
A vehicle in which a reference sideslip angle is estimated by a vehicle model using the wheel rotation speeds of the left and right steered wheels 3 measured by the wheel rotation speed measurement means 14 and the steering wheel angle measured by the steering wheel angle measurement means 15 as inputs. Model response calculation means 25,
The front-rear speed of the vehicle is estimated using the wheel rotation speeds of the left and right steered wheels 3, the steering wheel angle, the yaw rate measured by the yaw rate measuring means 16, and the reference sideslip angle estimated by the vehicle model response calculating means 25. First vehicle speed estimating means 27 for
Second vehicle speed estimating means 28 for estimating the longitudinal speed of the vehicle by integrating the longitudinal acceleration measured by the longitudinal acceleration measuring means 17
Before and after the vehicle estimated by either one of the first vehicle speed estimating means 27 and the second vehicle speed estimating means 28 according to a predetermined rule based on the traveling state of the vehicle determined by the traveling state determining means 26. A vehicle speed selecting means 29 for selecting a speed,
The vehicle speed selecting means 29 selects and outputs the longitudinal speed of the vehicle estimated by the first vehicle speed estimating means 27 in the normal state as the determined rule and outputs the vehicle speed. The traveling state determining means 26 causes the vehicle to travel. When it is determined that the state is the predetermined limit traveling state, the longitudinal speed of the vehicle estimated by the second vehicle speed estimating means 28 is selected and output.
The determined rule is a rule arbitrarily determined by design or the like, and is determined by seeking an appropriate rule by either one or both of a test and a simulation.
The running state of the vehicle includes a normal running state where the tire is running in a linear region and a limit running state where the tire is running in a non-linear region.
The defined limit running state is a running state arbitrarily set by design or the like, and is set by, for example, obtaining an appropriate non-linear region of the tire by one or both of a test and a simulation.
In this specification, the "wheel rotation speed" has the same meaning as the wheel rotation speed per unit time.

According to this configuration, the vehicle model response calculation means 25 estimates the reference sideslip angle by the vehicle model, using the wheel rotation speeds of the left and right steered wheels 3 and the steering wheel angle as inputs.
As the vehicle model, for example, a plane two-degree-of-freedom model (commonly called a plane two-wheel model) is used, but it is not limited to this plane two-wheel model.

  The first vehicle speed estimation means 27 estimates the longitudinal speed of the vehicle by using the wheel rotation speeds of the left and right steered wheels 3, the steering wheel angle, the yaw rate, and the standard sideslip angle. The vehicle speed selection means 29 selects the longitudinal speed of the vehicle estimated by the first vehicle speed estimation means 27 in a normal state (for example, in a state where the vehicle is traveling in a linear region of the tire (hereinafter, referred to as “normal traveling state”). In a normal running state, the reference sideslip angle can be estimated with good accuracy, so that the vehicle longitudinal speed estimated by the first vehicle speed estimating means 27 as described above is selected and output accurately. The longitudinal speed of the vehicle can be estimated.

  When the traveling state determination means 26 determines that the traveling state of the vehicle is in the predetermined limit traveling state, the vehicle speed selection means 29 selects and outputs the longitudinal speed of the vehicle estimated by the second vehicle speed estimation means 28. To do. In the limit traveling state, the estimation accuracy of the reference sideslip angle deteriorates, so the first vehicle speed estimating means 27 is not applied, but the second vehicle speed estimating means 28 is applied. The second vehicle speed estimating means 28 integrates the longitudinal acceleration measured by the longitudinal acceleration measuring means 17 to estimate the longitudinal speed of the vehicle. By limiting the time for the integral calculation when it is determined that the vehicle is in the limit running state, it is possible to prevent the estimation accuracy from deteriorating due to the accumulation of errors (drift). As described above, the longitudinal speed of the vehicle can be accurately estimated regardless of the traveling state of the vehicle.

A lateral acceleration measuring unit 17 for measuring the lateral acceleration of the vehicle is provided, and the vehicle model response calculating unit 25 receives the wheel rotational speeds of the left and right steered wheels 3 and the steering wheel angle as inputs, and sets a reference lateral acceleration according to the vehicle model or Estimate the reference yaw rate,
The running state determining means 26 determines whether the deviation between the lateral acceleration measured by the lateral acceleration measuring means 17 and the reference lateral acceleration is a threshold value or more, or the yaw rate and the reference yaw rate measured by the yaw rate measuring means 16. When the deviation is greater than or equal to the threshold value, it may be determined that the traveling state of the vehicle is the predetermined limit traveling state.
Each of the thresholds is a value arbitrarily determined by design or the like, and is determined by determining an appropriate value by one or both of a test and a simulation, for example.

  According to this configuration, when the deviation between the lateral acceleration actually occurring in the vehicle and the reference lateral acceleration is equal to or greater than the threshold value, or when the deviation between the yaw rate actually occurring in the vehicle and the reference yaw rate is equal to or greater than the threshold value, It can be considered that the vehicle is in a predetermined limit traveling state. By applying the second vehicle speed estimating means 28 in this limit traveling state, it is possible to accurately and accurately estimate the longitudinal speed of the vehicle.

  The vehicle is provided with a skid prevention control device 21 for preventing the skid of the vehicle and a braking control device 22 for controlling the braking force of the vehicle, and the traveling state determination means 26 includes the skid prevention control device 21 and the braking control device 22. When one or both of the above are operating, it may be determined that the traveling state of the vehicle is the predetermined limit traveling state. By applying the second vehicle speed estimation means 28 in such a limit traveling state, it is possible to accurately and accurately estimate the longitudinal speed of the vehicle.

  When the traveling state determining means 26 determines that the vehicle is in a predetermined limit traveling state, the front-rear speed of the vehicle estimated by the first vehicle speed estimating means 27 immediately before the determination is determined by the second vehicle speed estimating means 28. The initial value of the integral calculation of the longitudinal acceleration may be used. In this case, the longitudinal speed of the vehicle estimated by the second vehicle speed estimating means 28 can be estimated more accurately.

  A front-rear speed estimation device for a vehicle according to the present invention is a front-rear speed estimation device for estimating a front-rear speed in a vehicle including left and right steered wheels which are driven wheels and left and right drive wheels. A pair of wheel rotation speed measuring means for respectively measuring wheel rotation speeds, a steering wheel angle measuring means for measuring a steering wheel angle of the vehicle, a yaw rate measuring means for measuring a yaw rate of the vehicle, and a longitudinal acceleration of the vehicle. Longitudinal acceleration measuring means, running state determining means for determining whether the running state of the vehicle is a predetermined limit running state, and wheel rotation of the left and right steered wheels measured by the wheel rotation speed measuring means. Vehicle model response calculating means for estimating a reference sideslip angle by a vehicle model using speed and the steering wheel angle measured by the steering wheel angle measuring means as inputs, and the left and right sides. A first vehicle speed estimation for estimating the longitudinal speed of the vehicle using the wheel rotation speed of the steered wheels, the steering wheel angle, the yaw rate measured by the yaw rate measuring means, and the reference sideslip angle estimated by the vehicle model response calculating means. Based on the traveling state of the vehicle determined by the traveling state determining means, second means for estimating the longitudinal speed of the vehicle by integrating the longitudinal acceleration measured by the longitudinal acceleration measuring means, and estimating the longitudinal speed of the vehicle. A vehicle speed selecting means for selecting a longitudinal speed of the vehicle estimated by one of the first vehicle speed estimating means and the second vehicle speed estimating means according to a predetermined rule. The vehicle speed selecting means normally selects and outputs the longitudinal speed of the vehicle estimated by the first vehicle speed estimating means as the determined rule, and outputs the traveling state of the vehicle by the traveling state determining means. When it is determined that the vehicle is in the limit traveling state, the longitudinal speed of the vehicle estimated by the second vehicle speed estimating means is selected and output. Therefore, in a vehicle including steered wheels that are driven wheels and drive wheels, the longitudinal speed of the vehicle can be accurately estimated regardless of the traveling state of the vehicle.

FIG. 1 is a diagram schematically showing a system configuration of a vehicle longitudinal speed estimation device according to an embodiment of the present invention in a plan view. FIG. 3 is a sectional view of an in-wheel motor drive device of the vehicle. It is a block diagram of a control system of the same longitudinal speed estimation device. It is a figure which shows the correspondence of each symbol and the position of the same vehicle. It is a figure explaining the vehicle model in the same longitudinal speed estimation device. It is a figure which shows the relationship between a side slip angle and a lateral force.

A vehicle longitudinal speed estimating apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6.
FIG. 1 is a diagram schematically showing a system configuration of a vehicle longitudinal speed estimation device according to this embodiment in a plan view. In an electric vehicle 1 which is a vehicle equipped with this longitudinal speed estimation device, left and right rear wheels 2 are driving wheels driven by an electric motor 4 serving as a power source, and left and right front wheels 3 are driven wheels. The left and right front wheels 3 are steered wheels. Each motor 4 can generate a driving force and a braking force, respectively. Each motor 4 constitutes an in-wheel motor drive device IWM.

  As shown in FIG. 2, the in-wheel motor drive device IWM has a motor 4, a speed reducer 6, and a wheel bearing 7, and part or all of these are arranged in the rear wheel 2. The rotation of the motor 4 is transmitted to the rear wheel 2 via the speed reducer 6 and the wheel bearing 7. A brake rotor 8a forming a friction brake device 8 is fixed to a flange portion of the hub wheel 7a of the wheel bearing 7, and the brake rotor 8a rotates integrally with the rear wheel 2. The motor 4 is, for example, an embedded magnet type synchronous motor in which a permanent magnet is built in the core portion of the rotor 4a. The motor 4 is a motor in which a radial gap is provided between the stator 4b fixed to the housing 4c and the rotor 4a attached to the rotation output shaft 9.

The control system will be described.
As shown in FIG. 1, the front-rear speed estimation device 10 is a device that estimates the front-rear speed of the vehicle. The longitudinal speed estimation device 10 includes an ECU 11 mounted on a vehicle, an inverter device 12 provided for the motor 4, and sensors 13. The ECU 11 is composed of a computer such as a microcomputer, a program executed by the computer, and various electronic circuits. The ECU 11 and the inverter device 12 are connected, for example, by an in-vehicle communication network such as CAN (Control Area Network).

  The sensors 13 include a pair of wheel rotational speed measuring means 14 for measuring the wheel rotational speeds of the left and right front wheels 3, a steering wheel angle measuring means 15 for measuring the steering wheel angle of the vehicle, and a yaw rate measuring means for measuring the yaw rate of the vehicle. 16 and an acceleration sensor 17 that measures longitudinal acceleration and lateral acceleration of the vehicle. Further, the sensors 13 have an accelerator sensor 18a that detects the operation amount of the accelerator operation means 18 and a brake sensor 19a that detects the operation amount of the brake operation means 19.

  In this example, the ECU 11 includes a vehicle controller 20 shown below, a skid prevention control device (abbreviated as ESC) 21 that performs control for preventing skid of the vehicle, and a braking control device (abbreviated as ABS) 22 that controls the braking force of the vehicle. Have. An acceleration command from the accelerator operating means 18 and a deceleration command from the brake operating means 19 are input to the vehicle controller 20, and a braking / driving torque corresponding to the difference between the acceleration command and the deceleration command is supplied to the motor of the inverter device 12. It is given to the controller 12a. The motor controller 12a converts it into a current command according to the applied braking / driving torque, and gives the current command to the inverter 12b.

As shown in FIG. 3, the vehicle controller 20 includes a vehicle front-rear speed estimation device body 23 and a slip ratio control device 24. The longitudinal speed estimation device main body 23 has a vehicle model response calculation means 25, a traveling state determination means 26, a first vehicle speed estimation means 27, a second vehicle speed estimation means 28, and a vehicle speed selection means 29.
The vehicle model response calculation means 25 uses the vehicle model with the wheel rotation speed of the left and right front wheels 3 measured by the wheel rotation speed measurement means 14 and the steering wheel angle of the vehicle measured by the steering wheel angle measurement means 15 as inputs. Then, the reference side slip angle β _ref , the reference yaw rate γ _ref , and the reference lateral acceleration A _yref are calculated. A "norm" is attached to the state quantity obtained from the vehicle model. In this example, a plane two-degree-of-freedom model (commonly known as a plane two-wheel model) is used as the vehicle model.

The traveling state determination means 26 determines whether or not the traveling state of the vehicle is the predetermined limit traveling state. As shown in FIG. 6, the running state of the vehicle includes a normal running state where the tire is running in a linear region and a limit running state where the tire is running in a non-linear region.
As shown in FIG. 3, the traveling state determination unit 26 determines a deviation (hereinafter, referred to as “lateral _force”) between the _reference lateral acceleration A _yref calculated by the vehicle model response calculation unit 25 and the lateral acceleration A _y actually generated in the vehicle. (Hereinafter referred to as “acceleration deviation”) ΔA _y is greater than or equal to a certain threshold value, or a deviation between the reference yaw rate γ _ref calculated by the vehicle model response calculation means 25 and the yaw rate γ actually occurring in the vehicle (hereinafter, “yaw rate deviation”). )) Δγ is above a certain threshold value, it is determined that the traveling state of the vehicle is the limit traveling state.

The limit traveling state is a state in which the estimation accuracy of the reference sideslip angle β _ref estimated using the vehicle model is deteriorated. The lateral acceleration A _y actually generated in the vehicle is measured by the acceleration sensor 17 which is the lateral acceleration measuring means and the longitudinal acceleration measuring means. The yaw rate γ actually generated in the vehicle is measured by the yaw rate measuring means 16.

Further, the traveling state determination means 26 determines that the traveling state of the vehicle is the limit traveling state when one or both of the skid prevention control device 21 and the braking control device 22 are operating.
When none of the above-mentioned conditions is satisfied, the traveling state determination means 26 determines that the estimation accuracy of the reference sideslip angle β _ref estimated using the vehicle model is good (hereinafter, referred to as “normal traveling state”). To do.

The first vehicle speed estimating means 27 uses the wheel rotational speeds ω _FL and ω _FR of the left and right front wheels, the sideslip angle β, the steering wheel angle δ _h , and the yaw rate γ to calculate the vehicle from the following equations (a1) and (a2). to estimate the longitudinal velocity _{V x} of.

FIG. 4 is a diagram showing the correspondence between each symbol and the position of this vehicle. The description will be made with reference to FIG. 4 and FIG.
In equations (a1) and (a2), ω _FL and ω _FR are wheel rotational speeds of the left and right front wheels 3, β is a sideslip angle, δ _h is a steering wheel angle, γ is a yaw rate, δ is an actual steering angle, and R _F is a front wheel. Is the wheel radius, l _f (FIG. 5) is the distance from the center of gravity P (FIG. 5) to the axle position of the front wheel 3, and n is the steering gear ratio. The sideslip angle β is a reference sideslip angle estimated from a vehicle model in which the vehicle parameters, the steering wheel angle δ _h, and the wheel rotation speeds ω _FL and ω _FR of the steered wheels are input variables.

The vehicle model will be described.
1. Modeling In a four-wheel model ignoring roll motion, describing the equation of motion becomes very complicated because the forces and velocities in the front-back direction and lateral direction are considered for each wheel.
Therefore, consider a case where there is no difference in the tire characteristics of the left and right wheels and the actual steering angle is small. As a result, as shown in FIG. 5, the influence of the tread can be ignored, which facilitates the description of the equation of motion. This FIG. 5 is a model called a plane two-wheel model.

2. The equation of motion vehicle weight m, the actual steering angle [delta], the center of gravity when the distance between the front wheel axle-center-of-gravity position l _f, the distance between the axle-center-of-gravity position of the rear wheel viewed l _r, the vehicle from above Let r be the moment of rotation (yaw rate), β _f and β _{r be} the sideslip angles of the front and rear wheels, and Y _f and Y _r be the lateral forces (cornering forces) acting on the front and rear wheels, respectively.
If the absolute values of the sideslip angles of the front and rear wheels and the actual steering angle are much smaller than “1”, that is, | β _f |, | β _r |, | δ | << 1, these directions are You may think that it corresponds to the lateral direction of the vehicle. When the vehicle is viewed from directly above, the equations describing the lateral motion of the vehicle are as follows, where all angles are positive in the counterclockwise direction.

3. Transfer Functions By solving equations (11) and (12) as algebraic equations, the transfer functions of β and r for steering can be obtained.

When the sideslip angle β is estimated from the vehicle model, it can be estimated with good accuracy in the normal traveling state, but the accuracy is deteriorated in the limit traveling state.
Therefore, as shown in FIG. 3, the vehicle front-rear speed is estimated using the second vehicle speed estimating means 28 in the limit traveling state. The second vehicle speed estimation means 28 estimates the vehicle longitudinal speed V _x from the following equation (b1) using the vehicle longitudinal acceleration A _x output by the acceleration sensor 17.

Here, as V _xo , the longitudinal velocity V _{x of the} vehicle obtained from the equations (a1) and (a2) is used immediately before the traveling state determination means 26 determines that the vehicle is in the limit traveling state. In other words, when the traveling state determining means 26 determines that the vehicle is in the limit traveling state, the front-rear speed V _x of the vehicle estimated by the first vehicle speed estimating means 27 immediately before this determination is calculated by the second vehicle speed estimating means 28. The initial value of the integral calculation of longitudinal acceleration. The second vehicle speed estimation means 28 limits the time for integral calculation to the limit traveling state, thereby preventing the estimation accuracy from deteriorating due to the accumulation of errors (drift).

The vehicle speed selection means 29 selects and outputs the longitudinal speed V _x of the vehicle estimated by the first vehicle speed estimation means 27 when the traveling state determination means 26 determines that the vehicle is in the normal traveling state. The vehicle speed selection means 29 selects and outputs the longitudinal velocity V _x of the vehicle estimated by the second vehicle speed estimation means 28 when the traveling state determination means 26 determines that the vehicle is in the limit traveling state.

As shown in FIGS. 3 and 4, the slip ratio control device 24 determines, for example, the front-rear speed V _x of the vehicle estimated by the front-rear speed estimation device main body 23 and the yaw rate generated in the vehicle at the position of the drive wheel. Calculate the vehicle speed V _drv . In FIG. 4, the vehicle speed at the position of the left rear wheel 2 is represented by V _drvL, and the vehicle speed at the position of the right rear wheel 2 is represented by V _drvR .

As shown in FIGS. 3 and 4, the slip ratio control device 24 further calculates the slip ratio from the vehicle speed V _drv at the position of the drive wheels and the wheel rotation speed of the drive wheels, and sets this slip ratio as a target. The braking / driving torque generated in the motor of each driving wheel is controlled by feedback control based on the deviation from the slip ratio. In making this slip ratio control, by applying the longitudinal velocity estimation device can estimate the longitudinal velocity V _x of accurately vehicle.

  According to the longitudinal speed estimation device 10 described above, the reference side slip angle can be estimated with good accuracy in a so-called normal traveling state in which the vehicle travels in the linear region of the tire. Therefore, the first vehicle speed estimation means 27 estimates the reference sideslip angle. By selecting and outputting the longitudinal speed of the vehicle, the longitudinal speed of the vehicle can be accurately estimated.

  When the traveling state determination means 26 determines that the traveling state of the vehicle is the limit traveling state, the vehicle speed selection means 29 selects and outputs the longitudinal speed of the vehicle estimated by the second vehicle speed estimation means 28. In the limit traveling state, the estimation accuracy of the reference sideslip angle deteriorates, so the first vehicle speed estimating means 27 is not applied, but the second vehicle speed estimating means 28 is applied. The second vehicle speed estimating means 28 integrates the longitudinal acceleration measured by the acceleration sensor 17 to estimate the longitudinal speed of the vehicle. By limiting the time for the integral calculation when it is determined that the vehicle is in the limit running state, it is possible to prevent the estimation accuracy from deteriorating due to the accumulation of errors (drift). As described above, the longitudinal speed of the vehicle can be accurately estimated regardless of the traveling state of the vehicle.

Another embodiment will be described.
In the in-wheel motor drive device IWM, a cycloid type speed reducer, a planetary speed reducer, a two-axis parallel speed reducer, and other speed reducers can be applied, and a so-called direct motor type without a speed reducer is used. Good.
Although the above-described embodiment has been described using the in-wheel motor type electric vehicle, the outputs of the non-in-wheel motor type vehicle, for example, two motors installed in the vehicle body are output to the left and right via a drive shaft or the like. This control can also be applied to a so-called two-motor on-board vehicle that transmits to the drive wheels.
The longitudinal velocity estimated by the longitudinal velocity estimating device of the present embodiment may be used for a traction control device that prevents wheels from idling.

  Although the embodiments for carrying out the present invention have been described based on the embodiments, the embodiments disclosed this time are exemplifications in all respects and are not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1 ... Electric vehicle (vehicle)
2 ... Rear wheel (driving wheel)
3 ... Front wheels (driven wheels, steered wheels)
14 ... Wheel rotation speed measuring means 15 ... Steering wheel angle measuring means 16 ... Yaw rate measuring means 17 ... Acceleration sensor (longitudinal acceleration measuring means, lateral acceleration measuring means)
21 ... Side slip prevention control device 22 ... Braking control device 25 ... Vehicle model response calculation means 26 ... Running state determination means 27 ... First vehicle speed estimation means 28 ... Second vehicle speed estimation means 29 ... Vehicle speed selection means

Claims (4)

A front-rear speed estimation device that estimates a front-rear speed in a vehicle including left and right steered wheels that are driven wheels and left and right drive wheels,
A pair of wheel rotation speed measuring means for measuring the wheel rotation speeds of the left and right steered wheels, respectively,
Steering wheel angle measuring means for measuring the steering wheel angle of the vehicle,
Yaw rate measuring means for measuring the yaw rate of the vehicle,
Longitudinal acceleration measuring means for measuring longitudinal acceleration of the vehicle,
A traveling state determining means for determining whether the traveling state of the vehicle is a predetermined limit traveling state,
Vehicle model response calculation for estimating a reference sideslip angle by a vehicle model using the wheel rotation speeds of the left and right steered wheels measured by the wheel rotation speed measurement means and the steering wheel angle measured by the steering wheel angle measurement means as inputs Means and
A first longitudinal speed estimation of the vehicle using the wheel rotational speeds of the left and right steered wheels, the steering wheel angle, the yaw rate measured by the yaw rate measurement means, and the reference sideslip angle estimated by the vehicle model response calculation means. Vehicle speed estimation means of
Second vehicle speed estimating means for estimating the longitudinal speed of the vehicle by integrating the longitudinal acceleration measured by the longitudinal acceleration measuring means,
Based on the traveling state of the vehicle determined by the traveling state determination means, the longitudinal speed of the vehicle estimated by one of the first vehicle speed estimation means and the second vehicle speed estimation means is selected according to a predetermined rule. And a vehicle speed selection unit that
The vehicle speed selecting means normally selects and outputs the longitudinal speed of the vehicle estimated by the first vehicle speed estimating means as the determined rule, and outputs the traveling state of the vehicle by the traveling state determining means. When it is determined that the vehicle is in the limit traveling state, the vehicle front-rear speed estimating device selects and outputs the vehicle front-rear speed estimated by the second vehicle speed estimating means. The vehicle longitudinal speed estimating apparatus according to claim 1, further comprising a lateral acceleration measuring unit that measures a lateral acceleration of the vehicle, wherein the vehicle model response calculating unit includes wheel rotational speeds of the left and right steered wheels and the steering wheel angle. , Input the standard lateral acceleration or standard yaw rate from the vehicle model,
The running state determination means, when the deviation between the lateral acceleration measured by the lateral acceleration measuring means and the reference lateral acceleration is equal to or greater than a threshold value, or the deviation between the yaw rate measured by the yaw rate measuring means and the reference yaw rate. A front-rear speed estimation device for a vehicle, which determines that the traveling state of the vehicle is a predetermined limit traveling state when it is equal to or more than a threshold.   The forward / backward speed estimation device for a vehicle according to claim 1 or 2, further comprising a sideslip prevention control device for preventing sideslip of the vehicle and a braking control device for controlling a braking force of the vehicle. A vehicle front-rear speed estimation device that determines that the traveling state of the vehicle is a predetermined limit traveling state when one or both of the skid prevention control device and the braking control device are operating. In the vehicle longitudinal speed estimation device according to any one of claims 1 to 3, when the traveling state determination means determines that the vehicle is in a predetermined limit traveling state, immediately before the determination, the first A vehicle longitudinal speed estimating device, wherein the longitudinal speed of the vehicle estimated by the vehicle speed estimating means is used as an initial value of the integral calculation of the longitudinal acceleration in the second vehicle speed estimating means.

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