JPH10258617A - Tire inflation pressure estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate tire inflation pressure without being influenced by load variation at the time of starting without requiring operation of an initialization switch by estimating the tire air pressure from deviation of a current dynamic load value against a dynamic load initial value provided immerdiately after starting. SOLUTION: In the case when a dynamic load initial value βo is not preserved, the dynamic load initial value βo is computed by a step 514, and after a dynamic load value βave is computed by a step S14, discrimination of lowering of tire air pressure by a dynamic load is carried out by a step S16. In the case when the dynamic load initial value βo is preserved, the dynamic load value βave is computed by a step S22, it is judged whether air pressure is normal or it is adjusted by steps S24-S28, and at the time when it is normal or it is adjusted, codes of βo and βo-βave are cleared. Thereafter, the dynamic load initial value βo is computed by a step S29, and judgement of lowering of tire air pressure by the dynamic load is carried out by a step 30. Consequently, it is possible to estimate tire inflation pressure without requiring operation of an initialization switch and without being influenced by load variation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for estimating tire air pressure, and more particularly to an apparatus for estimating an air pressure of a tire and determining an abnormality.

[0002]

2. Description of the Related Art Wheel speed is used in a vehicle control device for controlling the motion of a vehicle by controlling the motion state of the wheel, for example, the slip ratio of the wheel and the braking / driving force. further,
It is also used in a wheel characteristic detecting device that detects a characteristic of a wheel such as a tire pressure of the wheel.

Conventionally, a tire pressure warning device has been developed which estimates the tire pressure of each wheel using the wheel speed or rotational angular speed of each of the four wheels, and issues, for example, an alarm when the tire pressure of any of the wheels drops. Have been. For example,
Japanese Patent Application Laid-Open No. 7-156621 detects the rotational angular velocities of each of the four wheels, and if the vehicle speed calculated when the initialization switch is operated by the driver is greater than a threshold value, the initial difference in the dynamic load radius of the wheels is calculated from the rotational angular velocities. It describes that a difference correction coefficient is obtained, and the initial difference is corrected based on the correction coefficient.

[0004]

In the conventional apparatus, the correction coefficient for the initial difference cannot be obtained unless the initialization switch is operated. For this reason, there is a problem that the tire air pressure is erroneously estimated unless the initialization switch is operated when the load changes. The present invention has been made in view of the above points, after starting, stored, or estimated tire pressure from the deviation between the dynamic load initial value obtained by learning the initial state and the current dynamic load value, By storing the dynamic load initial value at the time of tire pressure abnormality determination, a tire pressure estimation device that does not need to operate the initialization switch because the initial value in the abnormal state is not calculated and that can prevent erroneous estimation is provided. The purpose is to provide.

[0005]

As shown in FIG. 1, the invention according to claim 1 comprises a rotation detecting means M1 for detecting the rotation of each wheel of a vehicle, and a rotation detecting means M1 for detecting the rotation of each wheel obtained by the rotation detecting means. A dynamic load calculating means M2 for calculating a dynamic load corresponding to the variation of the tire radius of each wheel from the rotation detection signal, and a current dynamic load value with respect to a dynamic load initial value obtained immediately after starting or stored. Determining means M3 for estimating tire pressure from the deviation and determining whether the estimated tire pressure is abnormal;
Storage means M4 for storing the initial value of the dynamic load and the sign of the deviation when the abnormality of the tire pressure is determined; and determining whether or not the tire pressure is normal when the initial value of the dynamic load is stored. A discarding means M5 for discarding the dynamic load initial value stored in the storage means.

As described above, since the tire air pressure is estimated from the deviation of the current dynamic load value from the initial dynamic load value obtained immediately after the start, the tire is affected by the load fluctuation at the start without the need to operate the initialization switch. The tire pressure can be estimated without any problem, and erroneous estimation can be prevented. In addition, if there is an abnormality in the tire pressure, the dynamic load initial value at that time is stored, and after the next start, the tire pressure is estimated from the deviation of the current dynamic load value from the stored dynamic load initial value, and If the tire pressure is normal, the saved dynamic load initial value is discarded, so after the tire pressure abnormality determination, the dynamic load initial value saved when the next start is performed without adjusting the tire pressure Abnormality of the tire pressure can be determined without error from the deviation from the current dynamic load value, and when the tire pressure is adjusted and the next start is performed, the stored dynamic load initial value is discarded and a new dynamic pressure is discarded. The load initial value is obtained, and the tire pressure can be estimated without error.

According to a second aspect of the present invention, in the tire pressure estimating apparatus according to the first aspect, the discarding means sets a sign of a deviation of a current dynamic load value from the dynamic load initial value,
When the sign of the deviation is different from the sign of the deviation stored in the storage means, it is determined that the tire pressure is normal. This makes it possible to easily determine that the tire pressure has been adjusted after the determination of the tire pressure abnormality.

[0008] The invention according to claim 3 is the invention according to claim 1 or 2.
In the tire pressure estimating apparatus described above, the discarding unit is notified of whether the tire pressure is normal from an observer that estimates tire pressure based on a wheel dynamic model from the rotation detection signal. Thus, after the abnormality determination of the tire pressure, the fact that the tire pressure has been adjusted can be determined with high accuracy by a notification from an observer having high estimation accuracy of the tire pressure.

[0009]

FIG. 2 is a schematic diagram showing an embodiment of the apparatus according to the present invention. In the figure, the left and right front wheels 11, 12 and the left and right rear wheels 13, 14 are provided with wheel speed sensors 21, 22, 23, 24 as rotation detecting means M1, respectively. The wheel speed pulse of each of the four wheels detected at is supplied to an electronic control circuit (ECU) 25 and an observer 26. An alarm 30 is connected to the ECU 25.

As shown in FIG. 3, the ECU 25 includes a central processing unit (CPU) 40 and a read only memory (ROM) 4.
2 and a random access memory (R
AM) 44, an input port circuit 46, an output port circuit 48, a communication circuit 49, and an electric erasable programmable read only memory (EEPROM) 50, which is a non-volatile memory. Are connected to each other.

The input port circuit 46 includes a wheel speed sensor 21
24 to 24 are input. The communication circuit 49 is supplied with a message from the observer 26. The alarm 30 is connected to the output port circuit 48. First, the observer 26 will be described. The observer 26 is configured based on a model of the wheel shown in FIG. The wheels 70, when modeled as being connected by the rim 72 and moment of inertia J _B of the belt side 74 Togabane constant K of the torsion spring 76 of the inertia _{J R, (1) ~ (} 3) Is established, which constitutes a linear system.

_JR ω _R ′ = −Kθ _RB + T ₁ (1) J _B ω _B ′ = −Kθ _RB −T _d (2) θ _RB ′ = ω _R −ω _B. (3) where ω _R : angular velocity of the rim side 72 ω _R ': angular acceleration of the rim side 72 ω _B : angular velocity of the belt side 74 ω _B ': angular acceleration of the belt side 74 θ _RB : rim side The torsion angle between the portion 72 and the belt side portion T ₁ : drive / braking torque T _d : disturbance torque from the road surface Note that although a damper actually exists between the rim side portion 72 and the belt side portion 74, , Its impact is relatively small,
In the present embodiment, its existence is ignored.

If the above state equation is expressed using a vector and a matrix, the equation (4) is obtained.

[0014]

(Equation 1)

Here, the movement of the wheel 70 when the air pressure of the tire 78 changes and the spring constant of the torsion spring 76 changes from K to K + ΔK is expressed by the following equation (5).

[0016]

(Equation 2)

That is, a change in the spring constant K by ΔK is equivalent to the addition of a disturbance represented by the last term on the right side of the equation (5) to the normal tire 78. Since this disturbance includes information on the change amount ΔK of the spring constant K, and the spring constant K changes in accordance with the air pressure of the tire 78, the amount of change in the tire air pressure is estimated by estimating the disturbance. Can be estimated. The observer's method is used for estimating the disturbance. If the torque _Td from the road surface is also treated as a disturbance, the disturbance w to be estimated is expressed by the equation (6).

[0018]

(Equation 3)

However, theoretically, only one element of the disturbance [w] can be estimated, so that the second element w ₂ is estimated. By defining the disturbance w ₂ in (7), for the state equation of the wheel 70 is made as a (8), constituting the observer based on the equation (8). w ₂ = (− 1 / J _B ) T _d + (ΔK / J _B ) θ _RB (7)

[0020]

(Equation 4)

The observer estimates disturbance as one of the state variables of the system. Therefore, (8) for inclusion in the state of the disturbance w ₂ system equation to approximate the disturbance dynamics to be estimated by equation (10). w ₂ ′ = 0 (9) This means that the continuously changing disturbance is approximated stepwise (zero-order approximation), and the disturbance estimation speed of the observer is compared with the change of the disturbance to be estimated. If fast enough, this approximation is well tolerated. From the expression (9), if the disturbance w ₂ is included in the state of the system, the extended system of the expression (10) is configured.

[0022]

(Equation 5)

In equation (10), [w _B θ _RB
w ₂ ] ^T cannot be detected. Therefore, if an observer is configured based on this system,
The disturbance w ₂ and the state variables ω _B and θ _RB that cannot be measured originally can be estimated. To simplify the description, (1
The vector and the matrix of the expression (0) are decomposed and expressed as follows.

[0024]

(Equation 6)

At this time, the state [Z] = [ω _B θ _RB
The configuration of the minimum dimension observer for estimating w ₂ ] ^T is expressed by equation (11). [Z _p '] = [A ₂₁ ] [X _a ] + [A ₂₂ ] [Z _p ] + [B ₂ ] [u] + [G] ｛[X _a ′] − ([A ₁₁ ] [X _a ] + [A ₁₂ ] [Z _p ] + [B ₁ ] [u])｝ = ([A ₂₁ ] − [G] [A ₁₁ ]) [X _a ] + ([A ₂₂ ] − [G] [ _{A 12]) [Z p]} + [G] [X a '] + ([B 2] - [G] [B 1]) [u] ··· (11) However, [Z _p]: [Z ] [Z _p ']: Change rate of the estimated value [Z _p ] [G]: Gain that determines the estimated speed of the observer Also, the error [e] between the true value [Z] and the estimated value [Z _p ] Is set as [e] = [Z] − [Z _p ], and the change rate of the error [e] is set as [e ′], the relation of the equation (12) is obtained.

[E ′] = ([A ₂₂ ] − [G] [A ₁₂ ]) [e] (12) This represents the estimated characteristic of the observer, and is represented by a matrix ([A ₂₂ ] − [ G] [A ₁₂ ]), that is, the pole of the observer. Therefore, as the eigenvalue moves away from the origin on the left half of the s plane, the estimated speed of the observer increases. The observer gain [G] may be determined so as to achieve a desired estimated speed.

In the above description, the disturbance w ₂ is calculated by the equation (7).
That is, w ₂ = (1 / J _B ) T _d + (ΔK / J _B ) θ _RB
In as represented, of the observer, but the spring constant K of the torsion spring 76 has been described a structure of a portion for estimating a disturbance w ₂ in the case of change [Delta] K, the observer, the moment of inertia J _B of the belt side portions 74 If changes to J _B + ΔJ _B, as well as the moment of inertia J _R of the rim 72 is constructed in the same manner portion for estimating respective disturbances when changed to J _R + ΔJ _R.

As described above, whether the rotation speed v of the wheel 70 is
Angular velocity ω calculated in consideration of tire radius R_REnter
When the spring constant K of the torsion spring 76 changes by ΔK,
Disturbance w_Two, The moment of inertia J of the belt side 74_BBut
ΔJ_BDisturbance w when changed _Two, And the rim side 72
Moment of inertia J_RIs ΔJ_RDisturbance w when changed₁But
Estimated and disturbance estimate w_2p, W_2p w_1pIs obtained
However, along with those disturbances, the side of the belt that cannot be detected
74 angular velocity ω_B, Torsion angle between rim side and belt side
θ_RBAre estimated, and the estimated value ω_Bp, Θ_RBpGet
It is.

Thereafter, the angular acceleration ω _R 'and the angular acceleration estimated value ω are estimated from the angular speed ω _R of the rim side portion 72 detected by the preprocessing section and the estimated angular speed ω _Bp of the belt side portion 74.
_Bp 'is required. And the above ω _R ,
Filtering is performed for each of ω _Bp , ω _R ′, and ω _Bp ′, and only components in a frequency band (for example, a frequency of 20 Hz to 50 Hz) near the resonance frequency of the tire vibration are extracted.

The above disturbances w _2p , w _2p , w _1p , angular velocity ω _R ,
Correlation calculation and normalization are performed using ω _Bp , angular acceleration ω _R ′, ω _Bp ′, torsion angle θ _{RBp, and the} like, the change amount ΔK of the spring constant K of the torsion spring 76, and the moment of inertia of the rim side portion 72. J variation of _R .DELTA.J _R, variation .DELTA.J _B such moment of inertia J _B of the belt side 74 is obtained. Thereafter, the change amount ΔK is compared with a reference value ΔK _{0 in} a determination process. Change Δ
If K is smaller than the reference value ΔK ₀ , which is a negative value, it is determined that the air pressure of the tire 78 is abnormally low.
Will be informed. Note that the relationship between the change amount ΔK and the air pressure change amount ΔP is predetermined as an air pressure change table, and the air pressure change amount ΔP corresponding to the current change amount ΔK is obtained according to the relationship. Similarly, it is determined whether the amount of change ΔJ _B is greater than a reference value ΔJ _B0 that is a positive value,
If the determination is YES, the ECU 25 is notified that the tire 76 has caught foreign matter. Further, it is determined whether or not the amount of change ΔJ _B is smaller than the reference value −ΔJ _B0.
In the case of ES, the ECU 25 is notified that the wear of the tire 78 has reached an allowable limit and needs to be replaced. When the two determination results were both NO, no significant change in the moment of inertia J _B of the tire 78, the tire pressure is determined to be normal, made known to the ECU 25.

FIG. 5 shows a flowchart of one embodiment of the tire pressure estimation process executed by the CPU 40 of the ECU 25. This process is started when the ignition switch of the vehicle is turned on. In the figure, in a step S10, it is determined whether or not the dynamic load initial value β0 is stored in the EEPROM 50. Here, if the dynamic load initial value β0 is not stored, the dynamic load initial value β0 is calculated in step S12, and the dynamic load value βave is calculated in the next step S14.

Here, the dynamic load initial value β0 and the dynamic load value β
ave is calculated as follows. Wheel speed sensors 21 and 2
The wheel speed pulse detected by each of the four counters pfl, pf
It is counted separately for each of r, prl, and prr. Then, for example, the count value of the counter pfl becomes a predetermined value (for example, 300
00), the dynamic load β is calculated by equation (13).

Β = pfr−pfl−prr + prl (13) The dynamic load initial value β0 and the dynamic load value βave are the average values of the latest predetermined (for example, several) dynamic loads β. here,
Considering the dynamic load β which is the left-right difference between the front wheels and the right-left difference between the rear wheels, if the tire pressures of the four wheels 11 to 14 are normal and the tire radii of the respective wheels are substantially the same, pfr−pflｆ
0, prr-prl ≒ 0, and β ≒ 0. Also, for example, if the left or right of the front wheel is punctured and the tire radius becomes smaller, pfr-pfl = a, prr-prl
= 0 and β = a.

In the above step S12, the dynamic load initial value β
Although 0 is calculated, β0 is only stored in the RAM 44 and is not stored in the EEPROM 50. Step S1
After the execution of step 4, the process proceeds to step S16, and the determination of the decrease in tire air pressure due to the dynamic load is performed by the following equation. | Β0−βave |> βTH (14) The above βTH is a warning threshold value, for example, a value of about several hundreds. Here, if | β0−βave | ≦ βTH, it is determined that the tire pressures of all four wheels are normal, and step S14 is performed.
Proceed to. On the other hand, if | β0−βave |> βTH, it is determined that one of the tire pressures is abnormal, and the process proceeds to step S18. In step S18, the dynamic load initial value β0 calculated in step S12 is written and stored in the EEPROM 50. Next, in step S20, only the sign of [beta] 0- [beta] ave is taken out, written and stored in the EEPROM 50, and in step S21, an alarm is issued from the alarm device 30 for abnormal tire pressure, and the flow advances to step S14.

On the other hand, in step S10, the dynamic load initial value β0
Is stored in step S22, the dynamic load value β
Calculate ave. Next, in step S24, the observer 26
To determine whether there is a message indicating that the tire pressure is normal. If there is a message from the observer 26 that the tire pressure is abnormal, the process proceeds to step S26. In step S26, the dynamic load initial value β0 is read from the EEPROM 50, and the sign of β0−βave is obtained.
It is determined whether the stored code is different from the stored code read from the PROM 50, that is, whether the code is inverted.

At this time, during the previous operation, for example, the tire pressure of the right front wheel is reduced to determine that the tire pressure is abnormal, and the signs of dynamic load initial values β0 and β0−βave (for example, “negative”) are stored. Consider a case where the ignition switch is turned off, and then the ignition switch is turned on to start operation. When the right front tire is replenished with air after the ignition is turned off and the right front tire pressure becomes higher than the other three tire pressures, the sign of β0−βave is reversed (in this case, the sign is “positive”). . That is, when the sign of β0−βave is reversed in such a situation, it is determined that the adjustment of the tire pressure has been performed, and the process proceeds to step S28. Even when a message indicating that the tire pressure is normal is received from the observer 26, it is determined that the tire pressure has been adjusted, and the process proceeds to step S28.

In step S28, the signs of β0 and β0-βave stored in the EEPROM 50 are cleared.
Next, in step S29, the dynamic load initial value β0 is calculated, and the process proceeds to step S30. On the other hand, when there is a message of the tire pressure abnormality from the observer 26 and the sign of β0-βave is the same as the sign of β0-βave stored in the EEPROM 50, the tire pressure is not adjusted, so that the EEPROM 50 The process proceeds to step S30 without clearing the signs of the stored β0 and β0−βave.

In step S30, a determination of a decrease in tire air pressure due to a dynamic load is made according to equation (14). Where | β0
If −βave | ≦ βTH, the tire pressures of all four wheels are assumed to be normal, and the process proceeds to step S10. On the other hand, | β0−βav
If e |> βTH, it is determined that one of the tire air pressures is abnormal and the process proceeds to step S32. In step S32, the EEP
The dynamic load initial value β0 read from the ROM 50 or calculated in step S29 is written and stored in the EEPROM 50. Next, in step S34, only the sign of β0-βave is taken out, written and stored in the EEPROM 50,
In step S36, a warning of abnormal tire air pressure is issued from the alarm device 30, and the process proceeds to step S10.

Steps S14 and S22 correspond to the dynamic load calculating means M2, steps S16 and S30 correspond to the determining means M3, and steps S18, S20, S32, S
34 corresponds to the storage means M4, and corresponds to steps S24 and S2.
6, S28 correspond to the discarding means M5. As described above, since the tire air pressure is estimated from the deviation of the current dynamic load value from the initial dynamic load value obtained immediately after the start, the operation of the initialization switch is not required, and the tire is not affected by the load fluctuation at the start. The air pressure can be estimated, and erroneous estimation can be prevented. In addition, if there is an abnormality in the tire pressure, the dynamic load initial value at that time is stored, and after the next start, the tire pressure is estimated from the deviation of the current dynamic load value from the stored dynamic load initial value, and If the tire pressure is normal, the saved dynamic load initial value is discarded, so after the tire pressure abnormality determination, the dynamic load initial value saved when the next start is performed without adjusting the tire pressure Abnormality of the tire pressure can be determined without error from the deviation from the current dynamic load value, and when the tire pressure is adjusted and the next start is performed, the stored dynamic load initial value is discarded and a new dynamic pressure is discarded. The load initial value is obtained, and the tire pressure can be estimated without error.

[0040]

As described above, the first aspect of the present invention provides
As shown in FIG. 1, a rotation detecting means for detecting the rotation of each wheel of a vehicle, and a dynamic load corresponding to a variation in a tire radius of each wheel is calculated from a rotation detection signal of each wheel obtained by the rotation detecting means. Dynamic load calculating means, and a tire pressure is estimated from a deviation of a current dynamic load value from a dynamic load initial value obtained immediately after starting or stored, and it is determined whether or not the estimated tire pressure is abnormal. Judgment means, storage means for storing the sign of the dynamic load initial value and the deviation at the time of abnormality determination of the tire pressure, to determine whether the tire pressure is normal when the dynamic load initial value is stored, A discarding unit for discarding the dynamic load initial value stored in the storage unit in a normal state.

As described above, since the tire air pressure is estimated from the deviation of the current dynamic load value from the dynamic load initial value obtained immediately after the start, the tire is affected by the load fluctuation at the start without the need to operate the initialization switch. The tire pressure can be estimated without any problem, and erroneous estimation can be prevented. In addition, if there is an abnormality in the tire pressure, the dynamic load initial value at that time is stored, and after the next start, the tire pressure is estimated from the deviation of the current dynamic load value from the stored dynamic load initial value, and If the tire pressure is normal, the saved dynamic load initial value is discarded, so after the tire pressure abnormality determination, the dynamic load initial value saved when the next start is performed without adjusting the tire pressure Abnormality of the tire pressure can be determined without error from the deviation from the current dynamic load value, and when the tire pressure is adjusted and the next start is performed, the stored dynamic load initial value is discarded and a new dynamic pressure is discarded. The load initial value is obtained, and the tire pressure can be estimated without error.

Further, the invention described in claim 2 is the same as that in claim 1.
In the tire pressure estimating apparatus according to the above, the discarding means determines that the tire pressure is normal when the sign of the deviation of the current dynamic load value from the dynamic load initial value is different from the sign of the deviation stored in the storage means. I do.

Thus, it is possible to easily determine that the tire pressure has been adjusted after the determination of the tire pressure abnormality. According to a third aspect of the present invention, in the tire pressure estimating apparatus according to the first or second aspect, the discarding unit estimates a tire pressure based on a wheel dynamic model from the rotation detection signal. Is notified whether or not is normal.

Thus, after the abnormality determination of the tire pressure, the fact that the tire pressure has been adjusted can be determined with high accuracy by a notice from the observer having high estimation accuracy of the tire pressure.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a schematic configuration diagram of the present invention.

FIG. 3 is a block diagram of an ECU.

FIG. 4 is a diagram showing a dynamic model of a wheel.

FIG. 5 is a flowchart of a tire pressure warning process.

[Explanation of symbols]

 11-14 wheels 21-24 wheel speed sensor 25 ECU 26 observer 30 alarm device 40 CPU 42 ROM 44 RAM 46 input port circuit 48 output port circuit 49 communication circuit 70 wheel 72 rim side 74 belt side 76 torsion spring 78 tire M1 Rotation detection means M2 Dynamic load calculation means M3 Judgment means M4 Storage means M5 Discard means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Kawai 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Hideki 1 Toyota Motor Town Toyota City, Aichi Prefecture Toyota Motor Corporation ( 72) Inventor Masahiro Yoneya 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Jun Tokuman 1 Toyota Town Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Yuuki Mori Aichi Aichiin Seiki Co., Ltd., 2-1-1 Asahi-cho, Kariya-shi, Japan (72) Koji Umeno, 41 Toyota Chuo R & D Laboratories Co., Ltd.

Claims (3)

[Claims] 1. A rotation detecting means for detecting rotation of each wheel of a vehicle, and a dynamic load for calculating a dynamic load corresponding to a variation in a tire radius of each wheel from a rotation detection signal of each wheel obtained by the rotation detecting means. Load calculating means, and determining means for estimating a tire pressure from a deviation of a current dynamic load value from a dynamic load initial value obtained immediately after starting or stored, and determining whether the estimated tire pressure is abnormal or not. And a storage means for storing the sign of the dynamic load initial value and the deviation at the time of determination of an abnormality of the tire pressure, and determines whether the tire pressure is normal when the dynamic load initial value is stored, A tire pressure estimating device comprising: a discarding unit for discarding the dynamic load initial value stored in the storage unit. 2. The tire pressure estimating device according to claim 1, wherein the discarding unit is configured to set a sign of a deviation of a current dynamic load value from the initial value of the dynamic load to a sign of the deviation stored in the storage unit. An apparatus for estimating tire pressure, wherein the tire pressure is determined to be normal when different. 3. The tire pressure estimation device according to claim 1, wherein the discarding unit determines whether the tire pressure is normal from an observer that estimates a tire pressure based on a wheel dynamic model from the rotation detection signal. A tire pressure estimation device, which is notified.