JP7435900B2 - Vehicle attitude angle estimation device and optical axis control device for vehicle lamps - Google Patents

Description

The present disclosure relates to a device for estimating the attitude angle of a vehicle with respect to a road surface.

Patent Document 1 discloses a method of estimating the pitch angle of a vehicle with respect to a road surface using an acceleration sensor, an altitude sensor, and a vehicle speed sensor. Patent Document 1 discloses that an acceleration sensor is used to detect an absolute pitch angle, which is a pitch angle of a vehicle with respect to a horizontal plane, and a road surface gradient is calculated based on the amount of change in altitude per unit time measured by an altitude sensor. It is disclosed that a pitch angle relative to the road surface, which is the pitch angle of the vehicle relative to the road surface, is calculated from the difference between the road surface gradient and the absolute pitch angle.

Japanese Patent Application Publication No. 2013-112267

The pitch angle of a vehicle with respect to the road surface changes depending on the loading of passengers and cargo, and also changes due to changes in the slope of the road surface and acceleration/deceleration. If a vehicle is traveling at a constant speed on a road surface with a constant slope, it is possible to estimate the pitch angle of the vehicle from the horizontal plane by measuring the direction of gravity using an acceleration sensor as described in Patent Document 1. It is. Furthermore, by measuring the amount of change in altitude of the vehicle, it is possible to estimate the slope of the road surface on which the vehicle is traveling from the horizontal plane. It is possible to estimate the pitch angle of the vehicle relative to the pitch angle of the vehicle.

However, in a situation where the vehicle is accelerating or decelerating, the measured value of the acceleration sensor is not in the direction of gravity but in the composite direction of gravity and acceleration of the vehicle, so the pitch angle of the vehicle from the horizontal plane cannot be estimated. Further, in a situation where the acceleration of the vehicle is changing, the pitch angle acceleration of the vehicle due to the change in the acceleration of the vehicle is superimposed on the measurement value of the acceleration sensor. Similarly, in a situation where the slope of the road surface is changing, the pitch angular acceleration of the vehicle due to the change in the slope of the road surface is superimposed on the measurement value of the acceleration sensor. Therefore, with the method described in Patent Document 1, it is difficult to estimate the pitch angle of the vehicle with respect to the road surface when the vehicle is accelerating or decelerating or when the slope of the road surface is changing.

On the other hand, in order to realize optical axis leveling for anti-glare purposes of headlamps, for example, it is required to adjust the optical axis in response to pitch angle changes caused by acceleration and deceleration of the vehicle. For this purpose, it is necessary to estimate the pitch angle of the vehicle with respect to the road surface even while the vehicle is accelerating or decelerating.

The vehicle attitude angle estimation device according to the present disclosure includes:
In a vehicle equipped with a vehicle body supported from the road surface by a suspension, acceleration information obtained from an acceleration sensor provided on the vehicle body, altitude information obtained from at least an altitude sensor, vehicle speed information obtained from a vehicle speed sensor, and the suspension are determined. a static pitch angle estimation unit that estimates a static pitch angle that is a pitch angle of the vehicle body with respect to the road surface when the vehicle is not accelerating or decelerating on a flat road surface based on the constant;
a composite acceleration estimation unit that calculates a component of acceleration applied to the vehicle body parallel to the traveling direction of the vehicle from the acceleration information obtained from the acceleration sensor and the static pitch angle estimated by the static pitch angle estimation unit;
a pitch angle storage unit that stores the pitch angle of the vehicle body with respect to the road surface in the previous calculation cycle;
Determined by the component of the acceleration applied to the vehicle body parallel to the traveling direction of the vehicle estimated by the composite acceleration estimation unit, the pitch angle of the vehicle body with respect to the road surface in the previous calculation cycle stored in the pitch angle storage unit, and the suspension. The vehicle includes a pitch angle estimating section that estimates the pitch angle of the vehicle body with respect to the road surface from the constant, stores it in the pitch angle storage section, and outputs it to the output section.

Further, the optical axis control device for a vehicle lamp according to the present disclosure includes:
The vehicle attitude angle estimating device includes the vehicle attitude angle estimating device, and an optical axis control unit that controls the optical axis of the vehicle lamp based on the pitch angle estimated by the vehicle attitude angle estimating device.

According to the vehicle attitude angle estimating device of the present disclosure, it is possible to estimate the attitude angle of the vehicle even when the vehicle is accelerating or decelerating or when the road surface gradient is changing.

Further, according to the optical axis control device for a vehicle lamp according to the present disclosure, it is possible to appropriately control the optical axis of the vehicle lamp even during acceleration/deceleration of the vehicle or while the road surface gradient is changing.

FIG. 2 is a left side view of a vehicle having a vehicle body supported by a suspension. 1 is a configuration diagram of a vehicle attitude angle estimating device according to a first embodiment; FIG. 1 is a configuration diagram of a vehicle attitude angle estimating device according to a first embodiment; FIG. 1 is a configuration diagram of a vehicle attitude angle estimating device according to a first embodiment; FIG. FIG. 3 is a configuration diagram of a static pitch angle estimator in Embodiment 2. FIG. FIG. 2 is a rear side view of a vehicle having a vehicle body supported by a suspension. FIG. 7 is a configuration diagram of a vehicle attitude angle estimating device according to a fifth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The vehicle attitude angle estimating device of the present disclosure will be described below with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are indicated by the same reference numerals, and overlapping explanations will be omitted as appropriate.

Embodiment 1.
A vehicle attitude angle estimating device according to Embodiment 1 of the present disclosure will be described using FIGS. 1 and 2. FIG. 1 is a schematic diagram of a vehicle supported by a suspension and equipped with a vehicle attitude angle estimating device according to the first embodiment. FIG. 2 is a block diagram showing the configuration of the vehicle attitude angle estimating device according to the first embodiment.

As shown in FIG. 1, vehicle 100 has a vehicle body 104 and wheels 107. The wheels 107 are in contact with the road surface 103, and the left and right wheels 107 are connected by an axle 110. The vehicle body 104 is attached to an axle 110 via a suspension 102. Furthermore, the road surface 103 has a slope 108 with respect to the horizontal plane. Further, in FIG. 1, reference numeral 109 indicates the center of gravity of the vehicle 100.

The vehicle 100 is provided with a vehicle attitude angle estimation device 101, a headlamp 106, an acceleration sensor 201, an altitude sensor 202, and a vehicle speed sensor 203. Acceleration sensor 201 is fixed to vehicle body 104. The altitude sensor 202 is a sensor that detects the altitude of the vehicle, and may be a satellite positioning system, for example. Alternatively, the altitude sensor 202 may be a device that measures atmospheric pressure and converts it into altitude. The vehicle speed sensor 203 may be, for example, a sensor that determines the vehicle speed from the rotational speed of the wheels 107. Alternatively, the vehicle speed sensor 203 may be a device that estimates the speed of the vehicle from an image of an on-vehicle camera.

As shown in FIG. 2, the vehicle attitude angle estimation device 101 includes a static pitch angle estimation section 205, a composite acceleration estimation section 206, a pitch angle storage section 208, and a pitch angle estimation section 207.

Vehicle attitude angle estimating device 101 calculates at least vehicle acceleration information measured by acceleration sensor 201, altitude information of vehicle body 104 measured by altitude sensor 202, and vehicle speed at vehicle body 104 that is in contact with road surface 103 via suspension 102. Using the vehicle speed information measured by the sensor 203, the pitch angle 105 of the vehicle body 104 with respect to the road surface 103 is estimated and output to the output unit 204. The output unit 204 may be, for example, the optical axis control unit 111 of the headlamp 106. In this case, the optical axis control unit 111 of the headlamp 106 may be configured to be able to adjust the optical axis based on the pitch angle of the vehicle body estimated by the vehicle attitude angle estimation device 101.

The static pitch angle estimating unit 205 uses at least acceleration information obtained from the acceleration sensor 201, altitude information obtained from the altitude sensor 202, vehicle speed information obtained from the vehicle speed sensor 203, and a constant determined by the suspension 102. A static pitch angle, which is the pitch angle of the vehicle body 104 with respect to the road surface when the vehicle is not accelerating or decelerating on a flat road surface, is estimated.

The composite acceleration estimating unit 206 uses the acceleration information obtained from the acceleration sensor 201 and the static pitch angle estimated by the static pitch angle estimating unit 205 to calculate the component of the acceleration applied to the vehicle body 104 parallel to the vehicle traveling direction. calculate.

The pitch angle storage unit 208 stores the pitch angle of the vehicle body 104 with respect to the road surface estimated in the previous calculation cycle.

The pitch angle estimation unit 207 calculates the component of the acceleration applied to the vehicle body 104 parallel to the vehicle traveling direction estimated by the composite acceleration estimation unit 206 and the angle of the vehicle body 104 relative to the road surface in the previous calculation cycle stored in the pitch angle storage unit 208. The pitch angle of the vehicle body 104 with respect to the road surface is estimated using the pitch angle and a constant determined by the suspension. Further, the estimated pitch angle is stored in the pitch angle storage section 208 and outputted to the output section 204.

Next, the principle of pitch angle estimation in the vehicle attitude angle estimation device 101 of this embodiment will be explained.

As shown in FIG. 1, a coordinate system fixed to an axle 110 is used, with the vehicle traveling direction being the x-axis and the direction perpendicular to the road surface being the z-axis with the top being positive. Here, the wheels 107 are assumed to be rigid bodies, and the axles 110 of the front and rear wheels are always parallel to the road surface 103. At time t, the position of the vehicle center of gravity 109 in the coordinate system fixed to the axle 110 is p _0,t , its x coordinate is x _0,t , and its z coordinate is z _0,t .

The suspension 102 is a spring-damper system with a spring constant of k/4 and a damper coefficient of c/4, and the wheelbase of the vehicle is 2L. At this time, the pitch angle φ _t of the vehicle body with respect to the road surface at time t satisfies the angular motion equation expressed by the following equation (1).

Here, J _y is the moment of inertia of the vehicle around the center of gravity, M is the vehicle mass, d is the height of the vehicle center of gravity from the axle, θ _t is the road surface gradient 108 with respect to the horizontal plane, g is the gravitational acceleration, and V _t is the vehicle speed.

Further, φ _s is the pitch angle of the vehicle body 104 with respect to the road surface when the longitudinal acceleration V (dot) _t − gsinθ _t applied to the vehicle is zero. _φs changes depending on cargo and passengers getting on and off, but does not change while the vehicle is running. More precisely, it may change due to fuel consumption, etc., but the change is sufficiently small and φ _s can be considered constant in a short time. In this specification, φ _s is referred to as the static pitch angle.

The position _Pt of the acceleration sensor 201 attached to the vehicle body 104 in the coordinate system fixed to the axle 110 is expressed by the following equation (2).

However, p _0,t is the position of the vehicle center of gravity 109 in the coordinate system fixed to the axle 110, and r is the position of the acceleration sensor 201 when the vehicle center of gravity position p _0,t is the origin in the coordinate system fixed to the vehicle body 104. R _y (φ _t ) is a rotation matrix expressed by the following formula.

Since the acceleration of the acceleration sensor is the second-order differential of p _t , the following equation (3) holds true.

Since the acceleration measured by the acceleration sensor is the sum of its own acceleration plus gravity and inertial force, the acceleration measured by the acceleration sensor is expressed by the following equation (4) in a coordinate system fixed to the road surface. Ru.

However, G is a vertically upward gravitational acceleration vector, and F is an inertial force accompanying vehicle acceleration/deceleration and gradient change, and is expressed by the following formula.

Since the acceleration sensor is fixed to the vehicle body, the measured value _Ot of the acceleration sensor is the acceleration expressed by equation (4) rotated by the pitch angle of the vehicle body, and can be expressed as shown in equation (5) below. be done.

Since the suspension is constrained in the x-axis direction, the x component of the acceleration p (2 dots) _t of the acceleration sensor is 0. When equation (5) is approximated assuming that the pitch angle φ _t of the vehicle body is minute, the x and z components of the measurement value O _t of the acceleration sensor are expressed as shown in equation (6) below.

Using equation (1) and eliminating φ _t from equation (6), V (dots) _t - gsinθ _t and z (2 dots) _{0, t} - V _t θ (dots) _t + gcosθ _t become φ _s , It can be seen that it is determined as a function of φ (dot) _t and φ (2 dots) _t . Therefore, if these functions are denoted as ut and w _{t ,} respectively, they are expressed as shown in equation (7) below. Here, u _t and w _t correspond to a component parallel to the vehicle traveling direction and a component perpendicular to the vehicle traveling direction of the acceleration applied to the vehicle, respectively.

However, in equation (7), φ _t is obtained by solving equation (1) with respect to φ _t , and is a function of φ _s , φ(dot) _t , and φ(2 dots) _t .

Furthermore, in equation (7), values measured using an angular acceleration sensor or an angular velocity sensor (not shown) may be used as φ (dot) _t and φ (2 dots) _t . Alternatively, by arranging the acceleration sensor 201 near the vehicle center of gravity 109 and setting r≈0, terms related to φ (dot) _t and φ (2 dots) _t may be deleted from u _t and w _t . More preferably, the acceleration near the vehicle center of gravity position p _0,t may be calculated using a plurality of acceleration sensors or gyro sensors placed at different positions on the vehicle. Alternatively, by assuming that pitch angle changes due to gradient changes and vehicle acceleration/deceleration are relatively smooth, and ignoring high-frequency pitch angle changes resulting from suspension vibration modes, etc., φ (dot) _t ≒φ (2 dots) It may be approximated that _t≈0 .

Now, the following equation (8) holds true from equation (7).

In equation (8), V (dot) _t can be determined by numerically differentiating the vehicle speed V _t obtained from the vehicle speed sensor. Further, the right side of equation (8) is equal to the altitude change. Therefore, by numerically differentiating the altitude h _t measured by the altitude sensor 202 to obtain the altitude change and substituting it into the right side of equation (8), the static pitch angle φ _s can be calculated according to equation (8) in principle. can be found.

However, since the numerical differential V(dots) _t of vehicle speed and the numerical differential h(dots) _t of altitude include high-frequency errors emphasized by the numerical differentiation, (8) at one time t The static pitch angle φ _s obtained from the equation also includes a high frequency error. Therefore, in the calculation according to this embodiment, the static pitch angle φ _s is determined by the nonlinear least squares method using equation (8) at a plurality of times t. For the nonlinear least squares method, a known optimization method such as the conjugate gradient method or the quasi-Newton method may be used. Alternatively, a method specialized for the nonlinear least squares method such as the Levenberg-Marquard method may be used.

In addition, the numerical differential V (dots) _t of vehicle speed and the numerical differential h (dots) _t of altitude can be calculated by dividing the difference in values at two consecutive times by the time between the two times, for example. It's okay to ask. Alternatively, an incomplete differential filter may be used.

By substituting the static pitch angle φ _s estimated as above and the acceleration O _t measured by the acceleration sensor 201 into equation (7) to calculate u _t , the acceleration due to acceleration and deceleration of the vehicle and the gravitational acceleration can be calculated. The component V (dots) _t - gsinθ _t of the resultant acceleration parallel to the road surface traveling direction can be obtained.

Then, the component V (dots) _t - gsinθ _t parallel to the road surface traveling direction of the composite acceleration of the acceleration due to acceleration and deceleration of the vehicle and the gravitational acceleration is substituted into equation (1). Furthermore, by solving the initial value problem of equation (1) using the pitch angle φ _t-1 and pitch angular velocity φ (dots) _t-1 at time t-1, which is the previous calculation cycle, the pitch of the vehicle body with respect to the road surface is calculated. The angle φ _t and the pitch angular velocity φ (dots) _t can be determined. For example, the Euler method may be used to solve the initial value problem. Alternatively, the Runge-Kutta method may be used. Further, the determined pitch angle φ _t and pitch angular velocity φ (dots) _t may be stored in the storage unit for the next calculation cycle.

Next, the operation of the vehicle attitude angle estimating device 101 of this embodiment will be explained.

The static pitch angle estimating unit 205 calculates at least accelerations _Ot at a plurality of times t measured by the acceleration sensor 201, vehicle speeds Vt at a plurality of times t measured by the vehicle speed sensor 203, and vehicle speeds _Vt measured by the altitude sensor 202. The static pitch angle φ _s is estimated based on equation (8) from the altitude h _t at a plurality of times t and constants k and c determined by the suspension. Here, the coefficients k and c determined by the suspension may be stored in a storage unit (not shown).
The composite acceleration estimating unit 206 calculates a function _{u t (} φ _{s ;} φ(dot ) _t , φ (2 dots) _t ), the component V (dots) _t − gsinθ _t of the composite acceleration of the acceleration due to acceleration/deceleration of the vehicle and the gravitational acceleration parallel to the road surface traveling direction is calculated.
The pitch angle estimating unit 207 stores a component V (dots) _t - gsinθ _t parallel to the road surface traveling direction of the composite acceleration of the acceleration due to acceleration and deceleration of the vehicle and the gravitational acceleration calculated by the composite acceleration estimating unit 206, and the pitch angle storage unit. The pitch angle φ _t is calculated by solving the initial value problem of equation (1) using the pitch angle φ _t−1 at the previous calculation cycle, for example, time t−1, stored by the pitch angle storage unit 208. 208 and output to the output unit 204.

The vehicle attitude angle estimating device according to this embodiment makes it possible to estimate the pitch angle of the vehicle body with respect to the road surface even when the vehicle is accelerating or decelerating or when the gradient is changing.

In general, physical quantities such as acceleration and altitude change are differential quantities of position, and their measured values are essentially superimposed with high-frequency errors. In order to accurately estimate slope and pitch angle using such measured values, operations such as integration and averaging are essential. However, when operations such as integration and averaging are directly applied to gradients and pitch angles, it is necessary to assume that changes in road surface gradients and vehicle pitch angles are sufficiently small and constant during the target period. However, since the slope and pitch angle dynamically change during acceleration and deceleration of the vehicle or when the road surface slope changes, they cannot be considered constant. This is one of the reasons why the known methods cannot estimate the attitude angle of the vehicle while the vehicle is accelerating or decelerating or while the road surface slope is changing.

On the other hand, the vehicle attitude angle estimating device 101 of this embodiment does not directly apply operations equivalent to the integration and averaging to the slope and pitch angle, but instead uses a static pitch angle, which is an amount that does not change during driving. By applying the method to φ _s , the above-mentioned problem can be solved, and the attitude angle of the vehicle can be estimated during acceleration/deceleration of the vehicle or in a situation where the gradient is changing. The vehicle attitude angle estimating device 101 of this embodiment makes it possible to estimate the pitch angle φ _t of the vehicle body with respect to the road surface even when the vehicle is accelerating or decelerating or the road surface gradient is changing.

Note that the vehicle attitude angle estimating device 101 described in this embodiment is not limited to one that uses equation (1) as the angular motion equation of the pitch angle. Spring nonlinearities and suspension geometry effects may be introduced as long as the pitch angle φ _t is a function of the static pitch angles φ _s , φ(dots) _t , and φ(2 dots) _t .

Furthermore, in the vehicle attitude angle estimating device 101 according to the present embodiment, the static pitch angle estimating unit 205 is not limited to a form that performs static pitch angle estimation in every calculation cycle. Since the static pitch angle does not change during running, the static pitch angle estimating unit 205 estimates the static pitch angle once every N calculation cycles, where N is an integer, and the composite acceleration estimating unit 206 estimates the static pitch angle. The remaining calculations may be performed using the latest static pitch angle determined. As a result, the vehicle attitude angle estimating device 101 according to the present embodiment can calculate the pitch angle of the vehicle body without reducing the estimation period, even if the measurement period of the altitude sensor 202 is N times the measurement period of other sensors, for example. can be estimated.

Further, in the vehicle attitude angle estimating device 101 according to the present embodiment, the pitch angle estimating unit 207 further uses the angular velocity of the pitch angle of the vehicle body measured by an angular velocity sensor such as a gyro sensor, and may use, for example, a Kalman filter. The pitch angle may be estimated while removing noise. Thereby, even when noise is superimposed on the acceleration sensor 201, the vehicle attitude angle estimating device 101 can accurately estimate the pitch angle.

Furthermore, the vehicle attitude angle estimating device 101 of this embodiment and the optical axis control unit 111 that controls the optical axis of the vehicle lamp based on the pitch angle of the vehicle body with respect to the road surface estimated by the vehicle attitude angle estimating device 101 can be combined. Thus, an optical axis control device for a vehicle lamp may be configured. This makes it possible to appropriately control the optical axis of the vehicle lamp so as not to dazzle the driver of an oncoming vehicle even when the vehicle is accelerating or decelerating or the gradient is changing.

Furthermore, the functions of the static pitch angle estimating section, the composite acceleration estimating section, and the pitch angle estimating section in the vehicle attitude angle estimating device of this embodiment may be realized by a processing circuit as shown in FIG. 3. That is, the vehicle attitude angle estimating device may include a processing device for estimating a static pitch angle, estimating a composite acceleration, estimating a pitch angle, storing the estimated pitch angle in a pitch angle storage unit, and outputting the estimated pitch angle to an output unit. Even if the processing circuit is dedicated hardware, it may be a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, (also referred to as a processor or DSP).

If the processing circuit is dedicated hardware, the processing circuit may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. The functions of each part of the static pitch angle estimating part, the composite acceleration estimating part, and the pitch angle estimating part may be realized by a processing circuit, or the functions of each part may be realized by a processing circuit.

When the processing circuit is a CPU, the functions of the static pitch angle estimation section, the composite acceleration estimation section, and the pitch angle estimation section are realized by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in memory. The processing circuit realizes the functions of each part by reading and executing a program stored in the memory. That is, when executed by the processing circuit, the vehicle attitude angle estimating device performs a step of estimating a static pitch angle, a step of estimating a composite acceleration, estimating the pitch angle, storing it in the pitch angle storage unit, and outputting it to the output unit. A memory is provided for storing a program that results in the output steps being executed. It can also be said that these programs cause a computer to execute the procedures and methods of the static pitch angle estimation section, the composite acceleration estimation section, and the pitch angle estimation section. Here, memory includes, for example, nonvolatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, EEPROM, magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD, etc. do.

Note that each function of the static pitch angle estimating section, the composite acceleration estimating section, and the pitch angle estimating section may be partially realized by dedicated hardware, and partially realized by software or firmware. For example, the function of the static pitch angle estimator is realized by a dedicated hardware processing circuit, and for the synthetic acceleration estimator and pitch angle estimator, the processing circuit reads and executes a program stored in memory. By doing so, it is possible to realize this function.

In this way, the processing circuit can implement each of the above functions using hardware, software, firmware, or a combination thereof.

Embodiment 2.
The vehicle attitude angle estimating device 101A of this embodiment is the same as that of the first embodiment except for the static pitch angle estimating section. The static pitch angle estimator 205A in the vehicle attitude angle estimating device 101A of this embodiment will be described below with reference to FIG.

In this embodiment, the static pitch angle estimation section 205A includes a constant term calculation section 301, a differential coefficient calculation section 302, a static pitch angle calculation section 303, and a state storage section 304.

The constant term calculation unit 301 calculates a first constant term that does not depend on the static pitch angle among the components of the acceleration applied to the vehicle body 104 parallel to the vehicle traveling direction from the acceleration information obtained from the acceleration sensor 201.

The differential coefficient calculation unit 302 calculates, from the acceleration information obtained from the acceleration sensor 201, a first proportionality coefficient with respect to the static pitch angle among the components of the acceleration applied to the vehicle body 104 parallel to the vehicle traveling direction.

The state storage unit 304 stores at least the estimated value of the static pitch angle in the previous calculation cycle.

The static pitch angle calculation unit 303 calculates at least the altitude information obtained from the altitude sensor 202, the vehicle speed information obtained from the vehicle speed sensor 203, the first constant term calculated by the constant term calculation unit 301, and the differential coefficient calculation. The static pitch angle is estimated based on the first proportionality coefficient calculated by the section 302, the estimated value of the static pitch angle in the previous calculation cycle stored in the state storage section 304, and a constant determined by the suspension. do. Further, the estimated static pitch angle is stored in the state storage unit 304 and output to the composite acceleration estimation unit 206.

Next, the principle of static pitch angle estimation in the static pitch angle estimation unit 205A of the vehicle attitude angle estimation device 101A of this embodiment will be explained.

In this embodiment, the component u _t (φ _s ; φ(dot) _t , φ(2 dots) _t ) of the acceleration applied to the vehicle body 104 parallel to the vehicle traveling direction is approximated by a first-order Taylor expansion. Since u _t (φ _s ; φ (dot) _t , φ (2 dots) _t ) is a function of the static pitch angle φ _s , it is expressed as in the following equation (9).

In equation (9), values measured using an angular acceleration sensor or an angular velocity sensor (not shown) may be used as φ (dot) _t and φ (2 dots) _t . Alternatively, by arranging the acceleration sensor 201 near the vehicle center of gravity 109 and setting r≈0, terms related to φ (dot) _t and φ (2 dots) _t may be deleted from ut and wt. More preferably, the acceleration near the vehicle center of gravity p0, _t may be calculated using a plurality of acceleration sensors or gyro sensors placed at different positions on the vehicle. Alternatively, by assuming that changes in pitch angle due to changes in slope and acceleration/deceleration of the vehicle are relatively smooth, and ignoring high-frequency changes in pitch angle resulting from vibration modes of the suspension, φ (dot) t≒φ (2 dots) It may be approximated that t≈0.

Now, based on the approximation of equation (9), equation (8) can be transformed as shown in equation (10) below.

Since equation (10) is linear with respect to the static pitch angle φ _s to be estimated, the static pitch angle φ _s can be determined by the linear least squares method. This eliminates the need for repeated calculations required in the nonlinear least squares method, and the time required for calculations is determined. This is a desirable property in real-time calculations.

More preferably, by using an adaptive filter described below, it is possible to further reduce the amount of calculation. Specifically, the left side of the equation (10) is set as Y _t and the right side is set as U ^T _t ·φ _s , and the calculation expressed by the following equation (11) is executed every time. Here, U ^T _t indicates the transposed matrix of U _t . By repeating the calculation of equation (11), φ _s,t converges to φ _s . This allows the static pitch angle φ _s to be determined. Further, the determined static pitch angle φ _s may be stored in the storage unit for the next calculation cycle.

However, _Mt is expressed by the following formula (12).

In equations (11) and (12), λ _t is a predetermined constant called a forgetting coefficient, and represents how smoothly the static pitch angle φ _s can change. The forgetting factor may be a constant that does not depend on time. Alternatively, it may be variable depending on the speed. By using the forgetting coefficient, the static pitch angle estimation unit 205 does not need to hold acceleration, altitude, and vehicle speed at multiple times. Therefore, it is suitable for implementation in a microcontroller or the like with limited storage capacity.

Next, the operation of the vehicle attitude angle estimating device 101A of this embodiment will be explained.

The constant term calculation unit 301 calculates the first term on the right side of equation (9) from the acceleration O _t measured by the acceleration sensor 201. The first term on the right side of equation (9) is a constant term that does not depend on the static pitch angle _{φ s} of the component u t of the acceleration applied to the vehicle body 104 parallel to the vehicle traveling direction. In this specification, the constant term is also referred to as a first constant term.
The differential coefficient calculation unit 302 calculates the coefficient portion related to φ _s in the second term on the right side of equation (9) from the acceleration O _t measured by the acceleration sensor 201 . The coefficient is a proportional coefficient applied to the static pitch angle φ _s of the component u _t of the acceleration applied to the vehicle body 104 parallel to the vehicle traveling direction. In this specification, the proportionality coefficient is also referred to as a first proportionality coefficient.
The static pitch angle calculation unit 303 calculates at least the vehicle speed V _t measured by the vehicle speed sensor 203 , the altitude h _t measured by the altitude sensor 202 , and the first constant term calculated by the constant term calculation unit 301 . Based on the coefficient calculated by the differential coefficient calculation unit 302, the static pitch angle φ _s,t−1 one time before and the vector Φ _t−1 stored by the state storage unit 304, the adaptive filter of equation (11) is calculated. The static pitch angle φ _s,t and the vector Φ _t are calculated using , and are stored in the state storage unit 304 and output to the composite acceleration estimation unit 206 . Thereafter, the same processing as in Embodiment 1 is performed to estimate the pitch angle φ _t of the vehicle body with respect to the road surface.

According to the vehicle attitude angle estimating device 101A according to this embodiment, in addition to the effects described in Embodiment 1, the amount of calculation can be further reduced and processing suitable for real-time processing can be realized.

Note that the vehicle attitude angle estimating device 101A described in this embodiment is not necessarily limited to using equation (11) as an adaptive filter. For example, an LMS (least mean squares) filter or a total recursive least mean squares filter may be used as long as the static pitch angle φ _s can be determined based on equation (10).

Also in this embodiment, the static pitch angle estimating unit 205A is not limited to a form in which static pitch angle estimation is performed in every calculation cycle. Since the static pitch angle does not change during running, the static pitch angle estimating unit 205A estimates the static pitch angle once every N calculation cycles, where N is an integer, and the composite acceleration estimating unit 206 estimates the static pitch angle. The remaining calculations may be performed using the latest static pitch angle determined. Thereby, even if the measurement period of the altitude sensor 202 is N times the measurement period of other sensors, for example, the pitch angle of the vehicle body can be estimated without reducing the estimation period.

Further, as in the first embodiment, the optical axis of the vehicle lamp is controlled based on the vehicle attitude angle estimating device 101A of this embodiment and the pitch angle of the vehicle body with respect to the road surface estimated by the vehicle attitude angle estimating device 101A. In combination with the optical axis control section 111, an optical axis control device for a vehicle lamp may be configured.

Further, as in the first embodiment, each function of the constant term calculation section, differential coefficient calculation section, and static pitch angle calculation section in the static pitch angle estimation section of the vehicle attitude angle estimation device of this embodiment is performed by a processing circuit. It may be realized. That is, the static pitch angle estimator calculates the first constant term, calculates the first proportional coefficient, calculates the static pitch angle, stores it in the state storage unit, and outputs it to the composite acceleration estimation unit. may be equipped with a processing device. The processing circuit may be dedicated hardware or a CPU that executes a program stored in memory.

If the processing circuit is dedicated hardware, the processing circuit may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. The functions of each part of the constant term calculation part, the differential coefficient calculation part, and the static pitch angle calculation part may be realized by a processing circuit, or the functions of each part may be realized by a processing circuit.

When the processing circuit is a CPU, the functions of the constant term calculation section, differential coefficient calculation section, and static pitch angle calculation section are realized by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in memory. The processing circuit realizes the functions of each part by reading and executing a program stored in the memory. That is, when executed by the processing circuit, the vehicle attitude angle estimating device performs the steps of calculating a first constant term, calculating a first proportionality coefficient, and calculating a static pitch angle and storing it in the state storage unit. A memory is provided for storing a program that results in the step of outputting the output to the composite acceleration estimator. It can also be said that these programs cause a computer to execute the procedures and methods of the constant term calculation section, the differential coefficient calculation section, and the static pitch angle calculation section.

Note that each of the functions of the constant term calculation section, differential coefficient calculation section, and static pitch angle calculation section may be partially realized by dedicated hardware, and partially realized by software or firmware. For example, the functions of the constant term calculation section and the differential coefficient calculation section are realized by dedicated hardware processing circuits, and for the static pitch angle calculation section, the processing circuit reads and executes the program stored in memory. By doing so, it is possible to realize this function.

In this way, the processing circuit can implement each of the above functions using hardware, software, firmware, or a combination thereof.

Embodiment 3.
The vehicle attitude angle estimating device 101B in this embodiment has the same basic configuration as in Embodiment 1, but differs in that it takes into account the roll angle of the vehicle body. Specifically, of the measurement value _Ot measured by the acceleration sensor, the y component is considered in addition to the x component and the z component. In other words, components of three orthogonal axes are considered.

FIG. 6 is a rear side view of a vehicle having a vehicle body supported by a suspension. As shown in FIG. 6, the coordinates fixed to the axle 110 are as follows: the vehicle traveling direction is the x-axis, the direction perpendicular to the road surface is the z-axis with the top being positive, and the direction perpendicular to the x-axis and the z-axis is the y-axis. Take the system. The suspension 102 is a spring-damper system with a spring constant of k/4 and a damper coefficient of c/4, and the width between the left and right wheels is 2W. At this time, the roll angle ψ _t of the vehicle with respect to the road surface 103 at time t satisfies the angular motion equation expressed by the following equation (13).

However, ψ _t is the roll angle of the vehicle body with respect to the road surface, ψ _s is the static roll angle, η _t is the bank angle 402 of the road surface with respect to the horizontal plane, χ (dots) _t is the yaw rate, V _t χ (dots) _t is the lateral inertia force in the coordinate system fixed to the axle 110.

When the pitch angle φ _t and the roll angle φ _t of the vehicle body with respect to the road surface are small, the measured value O _t measured by the acceleration sensor is approximately expressed by the following equation (14).

If we eliminate φ _t and ψ _t from equation (14) using equations (1) and (13), we get V (dots) _t - gsinθ _t , y (2 dots) _{0, t} +V _t χ (dots) _t +g sin η _t cos θ _t and z (2 dots) _{0, t} −V _t θ (dot) _t + g cos η _t cos θ _t is determined as a function of φ _s and φ (dot) _t , φ (2 dot) _t . Therefore, if these functions are respectively denoted as ut _{, vt} , and _wt , they are expressed as shown in equation (15) below.

However, in equation (15), φ _t is obtained by solving equation (1) with respect to φ _t , and is a function of φ _s , φ (dot) _t , and φ (2 dots) _t . Similarly, ψ _t is obtained by solving equation (13) with respect to ψt, and is a function of ψ _s , ψ (dot) _t , and ψ (2 dots) _t .

Now, the dynamic roll angle of the car body can be estimated from the lateral acceleration applied to the car body and the properties of the suspension, but the static roll angle of the car body cannot be distinguished from the bank angle of the road surface and the acceleration sensor installed in the car body. I don't get it. Therefore, even if the static roll angle ψ _s is set to a small predetermined value, preferably 0, it does not affect other estimated values such as the pitch angle of the vehicle body. Therefore, in this embodiment, the static roll angle _ψs of the vehicle body is set to 0 or a predetermined value.

In equation (15), φ (dot) _t , ψ (dot) _t , φ (2 dot) _t , and ψ (2 dot) _t are measured using an angular velocity sensor such as a gyro sensor or an angular acceleration sensor (not shown). Values may be used. Alternatively, by arranging the acceleration sensor 201 near the vehicle center of gravity 109 and setting r≈0, φ (dot) _t , ψ (dot) _t , φ (2 dots) _t and ψ are obtained from u _t , v _t , w _t . (2 dots) The term related to _t may be deleted. More preferably, the acceleration near the vehicle center of gravity 109 may be calculated using a plurality of acceleration sensors or gyro sensors placed at different positions on the vehicle. Alternatively, by assuming that changes in pitch and roll angles due to changes in slope and acceleration/deceleration of the vehicle are relatively smooth, and ignoring high-frequency changes in pitch and roll angles resulting from vibration modes of the suspension, etc., It may be approximated as φ (dot) _t ≒ ψ (dot) _t ≒ φ (2 dots) _t ≒ ψ (2 dots) _t ≒ 0.

In the vehicle attitude angle estimating device 101B of this embodiment, instead of u _t (φ _s ; φ (dot) _t , φ (2 dots) _t ) used in Embodiment 1, u expressed by equation (15) is used. Using _t (φ _s , ψ _s ; φ (dot) _t , ψ (dot) _t , φ (2 dots) _t , ψ (2 dots) _t ), use equation (8) as in Embodiment 1. The static pitch angle φ _s can be determined by the nonlinear least squares method. Alternatively, as in the second embodiment, the static pitch angle φ _s can be determined by the linear least squares method using equation (10) or the adaptive filter using equation (11). Further, after determining the static pitch angle φ _s , the pitch angle φ _t of the vehicle body with respect to the road surface can be determined in the same manner as in the first embodiment.

When the acceleration sensor 201 is fixed to the vehicle body 104 and the vehicle body 104 is rolling, the z component of the acceleration applied to the acceleration sensor 201 is distributed into the z component and the y component of the measured value _Ot . Furthermore, while driving on a curved road, centrifugal force is superimposed on the vehicle. Therefore, when the vehicle body 104 is rolling or passing through a curved road, the attitude angle of the vehicle body 104 cannot be estimated correctly unless the y component is taken into account. On the other hand, according to the vehicle attitude angle estimating device 101B of this embodiment, since the y component of the measurement value _Ot of the acceleration sensor is taken into consideration, the vehicle body 104 is rolling or passing through a curved road. Even in this case, the attitude angle can be estimated correctly.

Note that the vehicle attitude angle estimating device 101B described in this embodiment is not limited to using equation (13) as the angular motion equation of the roll angle. As long as the roll angle ψ _t is a function of ψ _s , ψ(dots) _t and ψ(2 dots) _t , spring nonlinearity, suspension geometry effects, etc. may be introduced. Also, since the yaw rate χ (dots) _t is usually sufficiently smaller than the pitch angular velocity or the roll angular velocity, the term related to the yaw rate is ignored in equation (15) in the acceleration of the acceleration sensor with respect to the center of gravity. It is also permissible to use the measured value as the yaw rate.

Further, as in the first embodiment, the optical axis of the vehicle lamp is controlled based on the vehicle attitude angle estimating device 101B of this embodiment and the pitch angle of the vehicle body with respect to the road surface estimated by the vehicle attitude angle estimating device 101B. In combination with the optical axis control section 111, an optical axis control device for a vehicle lamp may be configured.

Embodiment 4.
The vehicle attitude angle estimating device 101C in this embodiment has the same basic configuration as the first embodiment, but differs in that the error of the vehicle speed sensor 203 is taken into account.

When using the measurement principle of the vehicle speed sensor 203, which is calculated by multiplying the rotational angular velocity of the wheel by the wheel radius, if the wheel radius has an error due to wheel wear or a decrease in air pressure, the measured vehicle speed will also have an error. have. Therefore, the vehicle speed measured by the vehicle speed sensor 203 is set as V _0,t , and the true vehicle speed V _t is expressed as shown in equation (16) below.

Here, к is a parameter representing the error in the wheel radius, and does not change in a short time. At this time, equation (8) is expressed as equation (17) below.

In the vehicle attitude angle estimating device 101C of this embodiment, the static pitch angle φ _s can be determined in the same manner as in the first embodiment by using equation (17) instead of the equation (8) used in the first embodiment. Can be done. Specifically, in equation (17), the static pitch angles φ _s and _к are simultaneously determined by the nonlinear least squares method using the static pitch angles φ s and к as variables. After determining the static pitch angle φ _s , the same process as in the first embodiment is performed to estimate the pitch angle φ _t of the vehicle body with respect to the road surface.

Similarly, by using the following equation (18) in place of equation (10), the adaptive filter described in the second embodiment can be constructed. Furthermore, it may be combined with Embodiment 3.

According to the vehicle attitude angle estimating device 101C of this embodiment, even if the measured value of the vehicle speed sensor 203 has an error due to an error in the wheel radius, the pitch angle can be accurately estimated.

In the vehicle attitude angle estimating device 101C according to the present embodiment, the vehicle speed sensor 203 may be one that multiplies the rotational speed of one wheel by the wheel radius, or the average rotational speed of a plurality of wheels. may be multiplied by the wheel radius.

Further, as in the first embodiment, the optical axis of the vehicle lamp is controlled based on the vehicle attitude angle estimating device 101C of this embodiment and the pitch angle of the vehicle body with respect to the road surface estimated by the vehicle attitude angle estimating device 101C. In combination with the optical axis control section 111, an optical axis control device for a vehicle lamp may be configured.

Embodiment 5.
A vehicle attitude angle estimating device 101D according to this embodiment will be explained using FIG. 7.
As shown in FIG. 7, the vehicle attitude angle estimation device 101D in this embodiment includes a coefficient storage section 501, a pitch angular velocity estimation section 502, and a coefficient prediction section 503 in addition to the vehicle attitude angle estimation device 101 of the first embodiment. .

The coefficient storage unit 501 stores a second constant term that does not depend on the static pitch angle of the pitch angular velocity of the vehicle body, and a second proportional coefficient with respect to the static pitch angle.

The pitch angular velocity estimation unit uses the second constant term in the previous calculation cycle stored in the coefficient storage unit 501, the second proportional coefficient in the previous calculation cycle, and the current value estimated by the static pitch angle estimation unit 205. The pitch angular velocity is estimated based on the estimated value of the static pitch angle in the calculation period of .

The coefficient prediction unit calculates a second constant in the next calculation cycle from the acceleration information obtained from the acceleration sensor 201, the pitch angle estimated by the pitch angle estimation unit 207, and the pitch angular velocity estimated by the pitch angular velocity estimation unit 502. The term and the second proportional coefficient are predicted and stored in the coefficient storage unit 501.

Further, the static pitch angle estimation unit 205 is determined based on acceleration information obtained from an acceleration sensor 201 provided in the vehicle body 104, altitude information obtained from at least an altitude sensor 202, vehicle speed information obtained from a vehicle speed sensor 203, and the suspension. In addition to the constant, a static pitch angle is estimated based on a second constant term and a second proportionality coefficient.

Next, the principle of pitch angle estimation in the vehicle attitude angle estimation device 101D of this embodiment will be explained. First, equation (6) is transformed as shown in equation (19) below.

From equation (19), it can be seen that V (dots) _t - gsinθ _t and z (2 dots) _{0, t} - V _t θ (dots) _t + gcosθ _t are linear with respect to φ (2 dots) _t . Therefore, the following formula (20) holds true.

If the inverse matrix lemma is used here, the following equation (21) holds true.

Therefore, the following formula (22) holds true.

For simplicity, the right side of equation (22) is set as shown below.

By substituting equation (22) into equation (1), a differential equation expressed by equation (23) below is obtained.

By solving the initial value problem of equation (23) using the Euler method, for example, the pitch angular velocity φ (dots) t at time t can be calculated from the pitch angle φ _t-1 and the pitch angular velocity φ (dots) _{t -1} one time before. , can be predicted in the form of the following equation (24), which is a linear form regarding the static pitch angle φ _s .

In equation (24) representing the pitch angular velocity φ (dots) _t , S _0,t is a constant term that does not depend on the static pitch angle φ _s , and S _1,t is a coefficient applied to the static pitch angle φ _s . . In this specification, S _0,t is also referred to as a second constant term, and S _1,t is also referred to as a second proportionality coefficient.

Further, by substituting equation (24) into equation (23) at time t, pitch angular acceleration φ (2 dots) _t at time t is determined as a function of static pitch angle φ _s . This is set as shown in equation (25) below.

Substituting equations (24) and (25) into equation (19) and further using equation (1) to eliminate φ _t , we get V (dots) _t - gsinθ _t and z (2 dots) _{0, t} - V _t θ (dot) _t + gcos θ _t is determined as a function of φ _s . Thereby, as in the first embodiment, φ _s can be estimated using the nonlinear least squares method using equation (8).

Next, the operation of the vehicle attitude angle estimating device 101D of this embodiment will be explained.
The coefficient storage unit 501 stores a constant term S _{0,tk and a proportional coefficient S 1,} tk of pitch angular velocity at a plurality of times t ₁ , ..., t _k , ..., t _{K , t} including time t. do.
The static pitch angle estimating unit 205 uses at least constant terms S _0,tk and proportional coefficients S _1,tk at multiple times stored in the coefficient storage unit 501 and accelerations at multiple times measured by the acceleration sensor 201. , the static pitch angle φ _s is estimated from the vehicle speed measured by the vehicle speed sensor 203 at a plurality of times and the altitude measured by the altitude sensor 202 at a plurality of times.
The pitch angular _velocity estimating _{unit 502} calculates ( 24) Calculate the pitch angular velocity φ (dots) _t using the formula.
The coefficient _prediction unit ₅₀₃ calculates ( 23) By solving the initial value problem of the equation using the Euler method, for example, constant terms S _{0, t+1} and proportional coefficients S _{1, t+1 at time t+1} , which is the next calculation cycle, are predicted and stored in the coefficient storage unit 501.

According to the vehicle attitude angle estimating device of this embodiment, in addition to the effects described in Embodiment 1, the pitch angle of the vehicle body derived from the vibration mode of the suspension 102 can also be estimated without using an additional sensor such as a gyro sensor. can. The vehicle attitude angle estimating device in this embodiment may also be combined with Embodiments 2 to 4 of the present disclosure, in which case the effects described in this embodiment are realized in addition to the effects described in Embodiments 2 to 4. can.

Further, as in the first embodiment, the optical axis of the vehicle lamp is controlled based on the vehicle attitude angle estimating device 101C of this embodiment and the pitch angle of the vehicle body with respect to the road surface estimated by the vehicle attitude angle estimating device 101C. In combination with the optical axis control section 111, an optical axis control device for a vehicle lamp may be configured.

In addition, as in the first embodiment, each function of the pitch angular velocity estimating section, coefficient predicting section, static pitch angle estimating section, composite acceleration estimating section, and pitch angle estimating section in the vehicle attitude angle estimating device of this embodiment includes processing. It may be realized by a circuit. That is, the vehicle attitude angle estimating device estimates the pitch angular velocity based on the second constant term and second proportional coefficient stored in the coefficient storage unit and the estimated static pitch angle, and estimates the pitch angular velocity in the next calculation cycle. The second constant term and the second proportional coefficient are predicted and stored in the coefficient storage unit, and the static pitch angle is estimated using the second constant term and the second proportional coefficient in addition to the measured values of each sensor. , a processing device may be provided for estimating the combined acceleration, estimating the pitch angle, storing it in the pitch angle storage unit, and outputting it to the output unit. Even if the processing circuit is dedicated hardware, it is a CPU (Central Processing Unit, also referred to as a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP) that executes a program stored in memory. It may be.

If the processing circuit is dedicated hardware, the processing circuit may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. The functions of each part of the pitch angular velocity estimation part, coefficient prediction part, static pitch angle estimation part, composite acceleration estimation part, and pitch angle estimation part may be realized by a processing circuit, or the functions of each part may be realized by a processing circuit. It's okay to make it happen.

When the processing circuit is a CPU, the functions of the pitch angular velocity estimation section, coefficient prediction section, static pitch angle estimation section, composite acceleration estimation section, and pitch angle estimation section are realized by software, firmware, or a combination of software and firmware. Ru. Software and firmware are written as programs and stored in memory. The processing circuit realizes the functions of each part by reading and executing a program stored in the memory. That is, when executed by the processing circuit, the vehicle attitude angle estimating device calculates the pitch angular velocity based on the second constant term and second proportional coefficient stored in the coefficient storage unit and the estimated static pitch angle. a step of estimating the second constant term and the second proportional coefficient in the next calculation cycle, and a step of storing the second constant term and the second proportional coefficient in the coefficient storage unit; A program that results in the steps of estimating a static pitch angle using coefficients, estimating a composite acceleration, estimating a pitch angle, storing it in a pitch angle storage unit, and outputting it to an output unit. Equipped with memory for storing. It can also be said that these programs cause a computer to execute the procedures and methods of the pitch angular velocity estimation section, coefficient prediction section, static pitch angle estimation section, composite acceleration estimation section, and pitch angle estimation section.

Note that some of the functions of the pitch angular velocity estimation section, coefficient prediction section, static pitch angle estimation section, composite acceleration estimation section, and pitch angle estimation section are realized by dedicated hardware, and some are realized by software or firmware. It may be realized. For example, the functions of the static pitch angle estimator are realized by a dedicated hardware processing circuit, and the processing circuits of the pitch angular velocity estimator, coefficient predictor, composite acceleration estimator, and pitch angle estimator are implemented in memory. The functions can be realized by reading and executing the stored program.

In this way, the processing circuit can implement each of the above functions using hardware, software, firmware, or a combination thereof.

Note that, within the scope of the present disclosure, the embodiments and modifications can be freely combined, and the embodiments and modifications can be modified or omitted as appropriate.

Although the present disclosure has been described in detail, the above description is illustrative in all aspects, and the present disclosure is not limited thereto. It is understood that countless variations not illustrated are envisioned without departing from the scope of this disclosure.

101, 101A, 101B, 101C, 101D vehicle attitude angle estimation device,
111 Optical axis control unit,
205, 205A static pitch angle estimator,
206 composite acceleration estimation unit,
207 pitch angle estimator,
208 pitch angle storage unit,
301 constant term calculation unit,
302 differential coefficient calculation unit,
303 Static pitch angle calculation unit,
304 state storage unit,
501 coefficient storage unit,
502 pitch angular velocity estimator,
503 Coefficient prediction unit

Claims (7)

In a vehicle equipped with a vehicle body supported from a road surface by a suspension, at least acceleration information obtained from an acceleration sensor provided on the vehicle body, altitude information obtained from an altitude sensor, vehicle speed information obtained from a vehicle speed sensor, and the suspension a static pitch angle estimation unit that estimates a static pitch angle that is a pitch angle of the vehicle body with respect to the road surface when the vehicle is not accelerating or decelerating on a flat road surface based on a determined constant;
a composite acceleration estimation unit that estimates a component of acceleration applied to the vehicle body parallel to the traveling direction of the vehicle from at least the acceleration information and the static pitch angle estimated by the static pitch angle estimation unit;
a pitch angle storage unit that stores the pitch angle of the vehicle body with respect to the road surface in the previous calculation cycle;
At least a component of the acceleration applied to the vehicle body estimated by the composite acceleration estimation unit parallel to the traveling direction of the vehicle, a pitch angle of the vehicle body with respect to the road surface in the previous calculation cycle stored in the pitch angle storage unit, and the suspension. a pitch angle estimation unit that estimates the pitch angle of the vehicle body with respect to the road surface from a constant determined by the pitch angle storage unit, and stores the pitch angle in the pitch angle storage unit and outputs it to the output unit;
A vehicle attitude angle estimation device equipped with The static pitch angle estimator includes:
a constant term calculation unit that calculates a first constant term that does not depend on a static pitch angle among components of acceleration applied to the vehicle body parallel to the traveling direction of the vehicle from acceleration information obtained from the acceleration sensor;
a differential coefficient calculation unit that calculates a first proportionality coefficient with respect to a static pitch angle among components of acceleration applied to the vehicle body parallel to the traveling direction of the vehicle from acceleration information obtained from the acceleration sensor;
a state storage unit that stores an estimated value of the static pitch angle in at least the previous calculation cycle;
At least, altitude information obtained from the altitude sensor, vehicle speed information obtained from the vehicle speed sensor, a first constant term calculated by the constant term calculation section, a first proportionality coefficient calculated by the differential coefficient calculation section, and a static pitch angle calculation for estimating a static pitch angle based on a constant determined by the suspension, storing the estimated value of the obtained static pitch angle in the state storage unit, and outputting it to the composite acceleration estimation unit. comprising a section,
The vehicle attitude angle estimation device according to claim 1. In addition to at least acceleration information obtained from an acceleration sensor provided in the vehicle body, altitude information obtained from an altitude sensor, vehicle speed information obtained from a vehicle speed sensor, and a constant determined by the suspension, Estimating the static pitch angle based on pitch angular velocity information obtained from the angular velocity sensor,
The vehicle attitude angle estimation device according to claim 1 or 2. A coefficient storage unit that stores a second constant term that does not depend on the static pitch angle among the pitch angular velocities of the vehicle body, and a second proportionality coefficient with respect to the static pitch angle;
Pitch angular velocity is estimated based on at least the second constant term and the second proportional coefficient stored in the coefficient storage unit, and the static pitch angle estimated by the static pitch angle estimation unit. a pitch angular velocity estimator;
The second constant term and the second constant term in the next calculation cycle are calculated from the acceleration information obtained from the acceleration sensor, the pitch angle estimated by the pitch angle estimator, and the pitch angular velocity estimated by the pitch angular velocity estimator. further comprising a coefficient prediction unit that predicts a proportional coefficient of 2 and stores it in the coefficient storage unit,
In addition to at least acceleration information obtained from an acceleration sensor provided in the vehicle body, altitude information obtained from an altitude sensor, vehicle speed information obtained from a vehicle speed sensor, and a constant determined by the suspension, estimating a static pitch angle based on the second constant term and the second proportionality coefficient;
The vehicle attitude angle estimation device according to claim 1 or 2. The static pitch angle estimation unit estimates the static pitch angle by considering components of three orthogonal axes among acceleration information obtained from an acceleration sensor provided in the vehicle body.
The vehicle attitude angle estimating device according to any one of claims 1 to 4. The static pitch angle estimation unit estimates a static pitch angle and also estimates an error in vehicle speed information obtained from the vehicle speed sensor.
The vehicle attitude angle estimation device according to any one of claims 1 to 5. A vehicle attitude angle estimating device according to any one of claims 1 to 6,
an optical axis control unit that controls an optical axis of a vehicle lamp based on the pitch angle estimated by the vehicle attitude angle estimation device;
Optical axis control device for vehicle lighting equipment.

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