Side slip angle calculation device

Abstract

To provide a side slip angle calculation device which can estimate a parameter required for estimating a side slip angle regardless of presence / absence of reception of a GNSS signal.SOLUTION: A vehicle parameter of a side slip angle calculation device 10 and an estimated side slip angle calculation block 28 calculate a vehicle parameter K that is a coefficient of approximating a side slip angle estimated value βest calculated by integrating a side slip angle differential value dβ, to a multiplication result Vωyaw obtained by multiplying the vehicle speed V by rotation angle speed ωyaw. The vehicle parameter and the estimated side slip angle calculation block 28 calculate an estimated side slip angle βEST by multiplying each of the vehicle parameter K, the vehicle speed V and the rotation angle speed ωyaw.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a sideslip angle calculation device for calculating a sideslip angle of a vehicle. [Background technology]

[0002] When a vehicle turns, a sideslip angle occurs. The yaw rate can only detect the direction the vehicle is facing, so in order to estimate the vehicle's traveling direction, it is necessary to estimate the vehicle's sideslip angle.

[0003] For this reason, for example, Non-Patent Document 1 discloses a method of estimating parameters required for estimating the sideslip angle by using GNSS Doppler, which is the relative velocity between the satellite and the receiver, and determining the sideslip angle. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "Research on GNSS / IMU Applicable in Urban Environments" Aoki Takanose, Yoshinori Atsumi, Kanamu Takikawa, Junichi Meguro, Transactions of the Society of Automotive Engineers of Japan, Vol. 51, No. 4, July 2020 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method described in Non-Patent Document 1 has a problem in that, in an environment in which GNSS signals cannot be received normally, the parameters required for estimating the sideslip angle cannot be estimated.

[0006] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide a sideslip angle calculation device capable of estimating parameters necessary for estimating a sideslip angle regardless of whether a GNSS signal is received or not. [Means for solving the problem]

[0007] In order to achieve the above object, a sideslip angle calculation device according to the present disclosure includes: Vehicle lateral acceleration (α y ), vehicle speed (V), and rotational angular velocity (ω yaw ) and the lateral acceleration (α y ), vehicle speed (V), and rotational angular velocity (ω yaw ) based on the vehicle's lateral slippage corner thrust Constant value (β est A sideslip angle estimated value calculation unit (14, 16, 20, 22) that calculates a sideslip angle estimated value ( Vehicle speed (V) and rotational angular velocity (ω yaw ) and the multiplication result (Vω yaw A multiplication unit (24) for calculating The estimated sideslip angle (β est ) and the multiplication result (Vω yaw and a parameter calculation unit (28) that calculates a parameter (K) that is a coefficient that approximates

[0008] The vehicle's sideslip angle is determined by the vehicle speed (V) and the rotational angular velocity (ω yaw ) and the multiplication result (Vω yaw ) and the parameter (K) calculated by the parameter calculation unit.

[0009] As described above, according to the sideslip angle calculation device of the present disclosure, the parameter (K) required for estimating the sideslip angle is calculated based on the sideslip angle estimated value (β est ) and the multiplication result (Vω yaw ) is calculated as a coefficient that approximates the side slip angle. Therefore, it is possible to calculate the parameter (K) required for estimating the sideslip angle regardless of whether or not a GNSS signal is received.

[0010] The reference numbers in parentheses above are merely an example of a correspondence with a specific configuration in an embodiment described below, in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0011] In addition to the above-mentioned features, the technical features described in each claim of the claims will become clear from the following description of the embodiments and the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing a configuration of a sideslip angle calculation device 10 according to a first embodiment. [Diagram 2] FIG. 2 is a waveform diagram showing an example of changes in travel angular velocity αy / V, which is obtained by dividing lateral acceleration αy by vehicle speed V, and rotational angular velocity ωyaw, when a vehicle turns right or left at an intersection. [Diagram 3] FIG. 11 is a waveform diagram showing an example of a change in a side slip angle differential value dβ from which an offset error dβ0 has been removed when a vehicle turns right or left at an intersection. [Figure 4] FIG. 11 is a waveform diagram showing an example of a change in a sideslip angle estimated value βest calculated by integrating a sideslip angle differential value dβ from which an offset error dβ0 has been removed when a vehicle turns right or left at an intersection. [Diagram 5] FIG. 5 is a waveform diagram showing an overlapping of the waveform of the estimated sideslip angle βest shown in FIG. 4, the waveform of the estimated sideslip angle βEST calculated by multiplying the waveform of the estimated sideslip angle βest by the vehicle parameter K, the vehicle speed V, and the rotational angular velocity ωyaw, and a waveform indicating the true value of the sideslip angle. [Figure 6] 4 is a flowchart showing a processing procedure for calculating an estimated slip angle βEST in a sideslip angle calculation device. [Figure 7] 4 is a flowchart showing a method for calculating a vehicle parameter K in the first embodiment. [Figure 8] 6A and 6B are waveform diagrams showing the temporal relationship between the change in the estimated side slip angle value βest and the side slip angle differential value dβ. [Figure 9] 10 is a flowchart showing a method for calculating a vehicle parameter K in the second embodiment. [Figure 10] FIG. 11 is a block diagram showing a configuration for implementing a method for calculating a vehicle parameter K according to a third embodiment. [Figure 11] FIG. 13 is a block diagram showing a configuration according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a side slip angle calculation device according to the present disclosure will be described in detail with reference to the drawings.

[0014] (First embodiment) FIG. 1 is a block diagram showing a configuration of a sideslip angle calculation device 10 according to a first embodiment. The sideslip angle calculation device 10 can be configured by, for example, a computer including at least one memory and one processor. The memory non-temporarily stores or stores computer-readable programs and data. The memory is realized by, for example, at least one type of non-transitory tangible storage medium among semiconductor memory, magnetic medium, optical medium, and the like. The memory stores programs for realizing at least a part of the functions of the sideslip angle calculation device 10 shown as a block in FIG. 1.

[0015] The processor includes at least one of a central processing unit (CPU), a graphics processing unit (GPU), and a reduced instruction set computer (RISC) CPU as a core. The processor executes a plurality of instructions included in a program stored in a memory to realize each function of the side slip angle calculation device 10 shown as a block in Fig. 1. Some of the functions shown as blocks may be realized by a hardware circuit.

[0016] The sideslip angle calculation device 10 receives signals from an acceleration sensor 1, a gyro sensor 2, a wheel speed sensor 3, and a Global Navigation Satellite System (GNSS) receiver 4. The sideslip angle calculation device 10 may be configured to receive signals from other sensors, etc., in addition to or instead of the above-mentioned sensors, etc., as necessary.

[0017] The acceleration sensor 1 detects a lateral acceleration α acting in the lateral direction (left-right direction) of the vehicle on which the side slip angle calculation device 10 is mounted. y The gyro sensor 2 detects the speed (yaw rate) ω yaw Detect.

[0018] The detection axis of the acceleration sensor 1 is installed on the vehicle so that it is horizontal to the ground. Therefore, when the vehicle rolls while turning and the detection axis of the acceleration sensor 1 tilts from the horizontal direction, the acceleration sensor 1 detects the gravitational acceleration in addition to the acceleration acting in the lateral direction of the vehicle due to the motion of the vehicle. For this reason, the sideslip angle calculation device 10 has a gravitational component elimination block 12. The gravitational component elimination block 12 removes the lateral acceleration α detected by the acceleration sensor 1. y From the above, the rotational angular velocity ω detected by the gyro sensor 2 is yaw Based on this, the gravity component corresponding to the magnitude of the inclination of the vehicle from the horizontal direction is removed. In this way, the sideslip angle calculation device 10 can calculate the highly accurate lateral acceleration α y can be obtained.

[0019] The wheel speed sensor 3 has, for example, a rotor with multiple teeth formed on its outer circumference and an electromagnetic pickup, and detects the speed at which the vehicle wheels rotate, i.e., the speed V at which the vehicle travels. Note that the wheel speed sensor 3 is not limited to the above-mentioned type, and other types of wheel speed sensors may also be used. The GNSS receiver 4 acquires vehicle position information and speed information based on signals from multiple positioning satellites.

[0020] The sideslip angle calculation device 10 has a vehicle speed correction block 18. The vehicle speed correction block 18 corrects the vehicle speed V detected by the wheel speed sensor 3 based on the speed information acquired by the GNSS receiver 4. For example, the vehicle speed V detected by the wheel speed sensor 3 may vary due to the influence of tire air pressure, the degree of tire wear, and the like. For this reason, the vehicle speed correction block 18 calculates a correction coefficient for correcting the vehicle speed V using accurate speed information acquired by the GNSS receiver 4. The vehicle speed correction block 18 corrects the vehicle speed V detected by the wheel speed sensor 3 using this correction coefficient. In this way, once the correction coefficient is calculated, the sideslip angle calculation device 10 can obtain a highly accurate vehicle speed V regardless of whether or not the speed information is acquired by the GNSS receiver 4. However, the GNSS receiver 4 and the vehicle speed correction block 18 may be omitted.

[0021] The side slip angle calculation device 10 includes band pass filter blocks 14 and 16. The band pass filter block 14 filters the lateral acceleration α y The bandpass filter block 16 also performs bandpass filtering on the rotational angular velocity ω yaw In this way, the lateral acceleration α y and rotational angular velocity ω yaw By applying band-pass filtering to the lateral acceleration α y and rotational angular velocity ω yaw Therefore, it is possible to remove high frequency noise and low frequency noise that are superimposed on the respective signals.

[0022] Lateral acceleration α y and rotational angular velocity ω yaw By performing band-pass filtering on the lateral acceleration αy and the rotational angular velocity ωyaw, it is possible to obtain an effect equivalent to that achieved by performing band-pass filtering on a sideslip angle differential value dβ, which will be described later. However, instead of or in addition to performing band-pass filtering on the lateral acceleration αy and the rotational angular velocity ωyaw, it is also possible to perform band-pass filtering on the sideslip angle differential value dβ.

[0023] The side slip angle calculation device 10 includes an error elimination calculation block 20. The error elimination calculation block 20 calculates the lateral acceleration α y , rotational angular velocity ω yaw , and vehicle speed V are input, and a sideslip angle differential value dβ is calculated according to the commonly known Equation 1 for sideslip angle differentiation.

number

[0024] If the output of each sensor contains an offset error due to temperature drift or the like, the influence of the offset error cannot be sufficiently removed by the band-pass filter blocks 14 and 16 alone. The sideslip angle estimated value β is obtained by integrating the sideslip angle differential value dβ while the offset error is included. est When the above is calculated, the estimated side slip angle β est will deviate significantly from the true sideslip angle β.

[0025] For this reason, the side slip angle calculation device 10 includes a scene determination block 26 that determines whether the vehicle is moving straight or turning. For example, the scene determination block 26 determines whether the vehicle is moving straight or turning based on the steering angle detected by the steering sensor and the rotational angular velocity ω yawBased on the magnitude of the difference, it can be determined whether the vehicle is traveling straight or turning. Then, based on the determination result of the scene determination block 26, the error elimination calculation block 20 determines the sideslip angle differential value dβ calculated when the vehicle is traveling straight before the vehicle starts turning as the offset error dβ0. The error elimination calculation block 20 calculates the sideslip angle differential value dβ by subtracting the offset error dβ0 from the sideslip angle differential value dβ calculated according to Equation 1. In this way, the error elimination calculation block 20 can output the sideslip angle differential value dβ from which the offset error dβ0 has been removed.

[0026] Fig. 3 is a waveform diagram showing an example of a change in the sideslip angle differential value dβ with the offset error dβ0 removed when the vehicle turns to turn right or left at an intersection. As shown in Fig. 3, by removing the offset error dβ0, the sideslip angle differential value dβ before the vehicle turns indicates an angular velocity of almost zero.

[0027] The side slip angle calculation device 10 includes an integration block 22. The integration block 22 integrates the side slip angle differential value dβ output from the error elimination calculation block 20 to obtain a side slip angle estimated value β est FIG. 4 shows the estimated side slip angle β calculated by the integration block 22 when the vehicle turns right or left at an intersection. est FIG. 13 is a waveform diagram showing an example of a change in

[0028] Here, referring to the waveform diagram of FIG. 5, the estimated side slip angle β shown in FIG. est As described above, the waveform of the lateral acceleration αy and the rotational angular velocity ω yaw By performing band-pass filtering on the side slip angle differential value dβ and removing the offset error dβ0 from the side slip angle differential value dβ, the side slip angle estimated value β est It can be seen that the calculated sideslip angle is almost equal to the true side slip angle.

[0029] However, errors that cannot be completely removed by the band-pass filter processing or the elimination of the offset error are accumulated by integration. As shown in FIG. 5, the estimated side slip angle β est It can be seen that the deviation between the actual side slip angle and the measured side slip angle becomes larger.

[0030] Therefore, in this embodiment, the estimated sideslip angle β est The estimated side slip angle β EST Instead of using the estimated side slip angle β est Estimate the sideslip angle β EST The vehicle parameter K and the estimated side slip angle β are used as the basis for determining the vehicle parameter K to calculate the vehicle slip angle β. est Explain the relationship between.

[0031] First, when a vehicle turns, the rotational centripetal force F acting on the vehicle is expressed by the following formula 2. Here, m is the vehicle weight, V is the speed of the vehicle in the direction of movement, and r is the turning radius.

number

[0032] The relationship between the sideslip angle β and the lateral force F is expressed by the following formula 3. Note that Cf indicates cornering power, which is the force generated per unit slip angle.

number

[0033] From Equation 2 and Equation 3, the vehicle parameter K and the estimated side slip angle β est Regarding the above, the following relational expression 4 is obtained.

number

[0034] In other words, the vehicle parameter K is the vehicle speed V and the rotational angular velocity ω yaw The result of multiplication with Vω yaw Estimated side slip angle βest This vehicle parameter K can be calculated as the ratio of the estimated side slip angle β est And the multiplication result Vω yaw For this reason, the side slip angle calculation device 10 calculates the vehicle speed V and the rotational angular velocity ω as shown in FIG. yaw Once the vehicle parameter K has been determined, the estimated side slip angle β EST is the vehicle parameter K, the vehicle speed V, and the rotational angular velocity ω yaw It can be calculated by multiplying each of these.

[0035] FIG. 5 shows the vehicle parameter K, the vehicle speed V, and the rotational angular velocity ω yaw The estimated side slip angle β is calculated by multiplying EST The waveform of the estimated side slip angle β EST is the estimated side slip angle β est Since it is not calculated by integration like est It can be seen that the error from the true side slip angle is smaller than that in the previous example.

[0036] The side slip angle calculation device 10 has a vehicle parameter and estimated side slip angle calculation block 28. As described above, the vehicle parameter and estimated side slip angle calculation block 28 calculates the vehicle speed V and the rotational angular velocity ω yaw The estimated side slip angle β for the multiplication result est Furthermore, once the vehicle parameter K is determined, the sideslip angle calculation device 10 calculates the vehicle parameter K, the vehicle speed V, and the rotational angular velocity ω as the sideslip angle occurring when the vehicle is turning. yaw The estimated side slip angle β is calculated by multiplying EST can be calculated.

[0037] The vehicle parameter and estimated sideslip angle calculation block 28 may be configured to calculate the vehicle parameter K and output the calculated vehicle parameter K to an external device that requires the sideslip angle (e.g., an automatic driving control device, a locator device, etc.). If the vehicle parameter K is known, the estimated sideslip angle β can be easily calculated in the external device. EST This is because it is possible to calculate

[0038] Next, referring to the flowchart of FIG. 6, the side slip angle calculation device 10 calculates the estimated slip angle β EST The procedure for calculating the above will be described.

[0039] First, in step S100, the side slip angle calculation device 10 calculates the lateral acceleration α y , rotational angular velocity ω yaw , and vehicle speed V, and calculates the sideslip angle differential value dβ according to the above-mentioned formula 1. A predetermined number of the calculated sideslip angle differential values ​​dβ are stored in memory. Note that, before the sideslip angle differential value dβ is calculated, the lateral acceleration α y is subjected to the above-mentioned gravity component removal and band-pass filtering, and the rotation angular velocity ω yaw is subjected to band pass filtering, and the vehicle speed V is subjected to vehicle speed correction processing.

[0040] In step S110, it is determined whether or not the vehicle is turning (driving on a curve) based on the detection value of the steering sensor and / or the gyro sensor 2. When the vehicle starts turning and the determination result of step S110 is "YES", in step S120, the offset error dβ0 is determined and stored in memory based on at least one side slip angle differential value dβ that has been calculated and stored in memory beforehand. On the other hand, when the determination result of step S110 is "NO", the process of step S100 is repeated until the determination result becomes "YES".

[0041] In step S130, it is determined whether or not the vehicle speed V is equal to or lower than a predetermined value (for example, 50 km / h). If the determination result in step S130 is "YES", the process proceeds to step S140, and if the determination result is "NO", the process returns to step S100.

[0042] When the vehicle speed increases, the vehicle motion characteristics also change, and there is a possibility that a vehicle parameter K different from that calculated at a low speed is calculated. A situation in which it is highly necessary to calculate the side slip angle using the vehicle parameter K is a situation in which the vehicle speed is relatively low, such as when the automatic driving control device accurately calculates the traveling direction of the vehicle using the side slip angle when the vehicle turns to turn right or left at an intersection. For this reason, in this embodiment, the vehicle parameter K is calculated by the determination process of step S130, limited to a low speed range in which the vehicle speed V is equal to or lower than a predetermined value. However, when it is necessary to calculate the side slip angle even in a medium speed range or a high speed range, the vehicle parameter K may be calculated for each of a plurality of speed ranges, such as a low speed range and a medium / high speed range, or a low speed range, a medium speed range, and a high speed range.

[0043] In step S140, the sideslip angle estimated value β is calculated by integrating the sideslip angle differential value dβ from which the offset error dβ0 stored in the memory was subtracted in the process of step S120. est In step S150, the vehicle speed V and the rotational angular velocity ω are calculated. yaw The multiplication result Vω yaw The estimated side slip angle β is calculated. est and the multiplication result Vω yaw is repeatedly calculated, for example, at predetermined time intervals while the vehicle is turning.

[0044] In step S160, the vehicle speed V and the rotational angular velocity ω yaw The result of multiplication with Vω yaw and the estimated side slip angle β est From this, the vehicle parameter K is calculated. An example of a method for calculating the vehicle parameter K will be described with reference to the flowchart of FIG.

[0045] In the first step S200, a plurality of estimated sideslip angles β are repeatedly calculated while the vehicle is turning. est Among these, the maximum side slip angle estimate MAX(β est As shown in Fig. 8(a) and (b), the maximum side slip angle estimated value MAX(β est ) generally occurs when the sign of the sideslip angle differential value dβ changes from positive to negative. Therefore, the estimated sideslip angle value β calculated when the sign of the sideslip angle differential value dβ changes from positive to negative est Maximum side slip angle estimated value MAX(β est ) or the repeatedly calculated estimated side slip angle β est The largest side slip angle estimate β est Maximum side slip angle estimated value MAX(β est ) may be specified.

[0046] In step S210, a plurality of vehicle speeds V and rotational angular velocities ω are repeatedly calculated while the vehicle is turning. yaw The result of multiplication with Vω yaw Among them, the maximum multiplication result MAX(Vω yaw ) is determined. The maximum multiplication result MAX(Vω yaw ), the maximum side slip angle estimate MAX(β est The multiplication result Vω is calculated at the same time that yaw Maximum multiplication result MAX(Vω yaw ) or the iteratively calculated multiplication result Vω yaw The largest multiplication result Vω is obtained by comparing the values ​​of yaw Maximum multiplication result MAX(Vω yaw ) may be specified.

[0047] In step S220, the maximum side slip angle estimated value MAX(β est ) is the maximum multiplication result MAX(Vω yaw In other words, the vehicle parameter K is calculated by dividing the vehicle speed V and the rotational angular velocity ω yaw The multiplication result Vωyaw The estimated side slip angle β for the maximum value of est In this way, the vehicle parameter K is calculated as the ratio of the maximum values ​​of the estimated sideslip angle β est and the multiplication result Vω yaw It is possible to improve the S / N ratio of each of the above, and calculate the vehicle parameter K with the influence of noise reduced as much as possible.

[0048] Returning to the flowchart of FIG. 6, in step S170, the vehicle parameter K calculated in step S160 is used to calculate the vehicle speed V and the rotational angular velocity ω yaw The result of multiplication with Vω yaw The sideslip angle β is calculated by further multiplying the calculated sideslip angle β by the vehicle parameter K. In step S180, it is determined whether the calculated sideslip angle β is equal to or smaller than a predetermined upper limit (for example, a value in the range of 3 to 5 degrees). This predetermined upper limit corresponds to the upper limit of the sideslip angle during normal vehicle driving. Therefore, if it is determined in step S180 that the calculated sideslip angle β is greater than the predetermined upper limit, it is highly likely that the vehicle parameter K was not calculated correctly. For this reason, if the determination result in step S180 is "NO", the process returns to the process in step S100 without storing the calculated vehicle parameter K in memory. On the other hand, if the determination result in step S180 is "YES", the process proceeds to step S190 and the calculated vehicle parameter K is stored in memory. Then, the sideslip angle calculation device 10 uses the vehicle parameter K stored in the memory to calculate the estimated sideslip angle β EST The vehicle parameter K stored in the memory can be used to calculate the vehicle's sideslip angle until a new vehicle parameter K is calculated.

[0049] As described above, according to the side slip angle calculation device 10 of the present embodiment, the vehicle parameter K required for estimating the side slip angle β is calculated by integrating the side slip angle differential value dβ. est , vehicle speed V and rotational angular velocity ω yaw The result of multiplication with Vω yawTherefore, it is possible to calculate the vehicle parameter K required for estimating the sideslip angle, regardless of whether or not a GNSS signal is received.

[0050] Second embodiment Next, a second embodiment of the side slip angle calculation device 10 according to the present disclosure will be described with reference to the drawings.

[0051] In the first embodiment described above, the maximum side slip angle estimated value MAX(β est ) is the maximum multiplication result MAX(Vω yaw ) to calculate the vehicle parameter K. However, the method of calculating the vehicle parameter K is not limited to the method described in the first embodiment, and other methods may be adopted. In this embodiment, a method of calculating the vehicle parameter K different from that in the first embodiment will be described.

[0052] 9 is a flowchart showing a method for calculating the vehicle parameter K in this embodiment. In the first step S300, while the vehicle is turning, the estimated side slip angle β est By repeatedly calculating the estimated side slip angle β est In step S310, the estimated side slip angle β est In synchronization with the calculation of the vehicle speed V and the rotational angular velocity ω yaw The result of multiplication with Vω yaw is calculated multiple times.

[0053] In step S320, the side slip angle estimated value β est and the vehicle speed V and rotational angular velocity ω calculated multiple times. yaw The result of multiplication with Vω yaw and calculate a plurality of vehicle parameters K as a ratio between those calculated synchronously. In step S330, the plurality of vehicle parameters K are statistically processed to determine one vehicle parameter K. The statistical processing may be, for example, a process to find the most frequently occurring value of the plurality of vehicle parameters K. Alternatively, the statistical processing may be a process to find an average of the plurality of vehicle parameters K after excluding obvious outliers.

[0054] In this manner, the vehicle parameter K necessary for estimating the sideslip angle can be calculated by the method of calculating the vehicle parameter K according to the second embodiment, similarly to the first embodiment.

[0055] Third embodiment Next, a third embodiment of the side slip angle calculation device 10 according to the present disclosure will be described with reference to the drawings. In this embodiment, as in the second embodiment, a method of calculating the vehicle parameter K that is different from that in the first embodiment will be described. Fig. 10 is a configuration diagram showing a configuration for implementing the method of calculating the vehicle parameter K according to this embodiment.

[0056] In FIG. 10, a control circuit 30 detects a rotational angular velocity ω yaw Whether or not the vehicle is turning is determined based on the signal, and when it is determined that the vehicle is turning, an enable signal is output to the adaptive filter 32.

[0057] The adaptive filter 32 is enabled when an enable signal is output from the control circuit 30. When the adaptive filter 32 is enabled, it calculates the estimated side slip angle β according to an optimization algorithm such as a least mean squares (LMS) algorithm or a recursive least squares (RLS) algorithm. est The waveform of the vehicle speed V and the rotational angular velocity ω yaw The transfer function H(z) is self-adapted so that the error e between the waveform of the vehicle and the estimated side slip angle is minimized. From the self-adapted transfer function H(z), the vehicle parameter and estimated side slip angle calculation block 28 can determine the vehicle parameter K.

[0058] In this manner, the vehicle parameter K required for estimating the sideslip angle can be calculated by the method of calculating the vehicle parameter K according to the third embodiment, similarly to the first embodiment.

[0059] Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the present disclosure.

[0060] For example, in each of the above-described embodiments, as shown in FIG. 11 , a road surface condition determination block 36 that determines the condition of the road surface on which the vehicle is traveling, and a K-value table 38 that serves as a parameter storage unit that stores the vehicle parameters K calculated by the vehicle parameter and estimated sideslip angle calculation block 28 and updates the stored vehicle parameters K may be provided.

[0061] The road surface condition determination block 36, for example, performs image recognition processing on the image of the vehicle surroundings captured by a camera to determine whether the road surface on which the vehicle is traveling is a sunny road surface, a rainy road surface, or a snowy road surface. However, the road surface condition is not limited to image recognition, and may be determined, for example, by the vehicle speed V and the rotational angular velocity ω when the vehicle is turning. yaw The result of multiplication with Vω yaw The magnitude of lateral acceleration α y and the angular velocity ω yaw In this case, the presence or absence of wiper operation, the outside air temperature, etc. may be taken into consideration.

[0062] The K value table 38 stores the vehicle parameters K in association with each road surface condition. When a new vehicle parameter K is calculated, the K value table 38 updates the vehicle parameter K stored in association with the road surface condition from which the vehicle parameter K was calculated with the latest vehicle parameter K.

[0063] The vehicle parameter K varies depending on the number of occupants in the vehicle, the amount of luggage, the degree of tire wear, and the road surface conditions. Among these variable factors, the road surface conditions are the main variable that may change while the vehicle is traveling.

[0064] In this regard, as described above, if the vehicle parameter K is stored in the K value table 38 in association with each road surface condition, it becomes possible to select the vehicle parameter K appropriate for each road surface condition based on the determination result of the road surface condition on which the vehicle is traveling by the road surface condition determination block 36, and the multiplication block 40 can calculate the sideslip angle with high accuracy using the selected vehicle parameter K.

[0065] In each of the above-described embodiments, the estimated side slip angle β est , vehicle speed V and rotational angular velocity ω yaw The result of multiplication with Vω yaw Although the vehicle parameter K is used as a coefficient for approximating and, the cornering power Cf may also be used. This is because the vehicle parameter K and the cornering power Cf have a certain relationship shown in Equation 4. [Explanation of symbols]

[0066] 1: acceleration sensor, 2: gyro sensor, 3: wheel speed sensor, 4: GNSS receiver, 10: sideslip angle calculation device, 12: gravity component removal block, 14: bandpass filter block, 16: bandpass filter block, 18: vehicle speed correction block, 20: error removal calculation block, 22: integration block, 24: multiplication block, 26: scene determination block, 28: angle calculation block, 30: control circuit, 32: adaptive filter, 36: road surface condition determination block, 38: K value table, 40: multiplication block

Claims

1. Vehicle lateral acceleration (α ｙ ), vehicle speed (V), and rotational angular velocity (ω ｙａｗ ) and the lateral acceleration (α ｙ ), vehicle speed (V), and rotational angular velocity (ω ｙａｗ ), the vehicle's side slip angle estimate (β ｅｓｔ A sideslip angle estimated value calculation unit (14, 16, 20, 22) that calculates a sideslip angle estimated value ( Vehicle speed (V) and rotational angular velocity (ω ｙａｗ ) and the multiplication result (Vω ｙａｗ A multiplication unit (24) for calculating The estimated sideslip angle (β ｅｓｔ ) and the multiplication result (Vω ｙａｗ and a parameter calculation unit (28) for calculating a parameter (K) which is a coefficient for approximating The vehicle's sideslip angle is determined by the vehicle speed (V) and the rotational angular velocity (ω ｙａｗ ) and the multiplication result (Vω ｙａｗ ) and the parameter (K) calculated by the parameter calculation unit.

2. The sideslip angle estimated value calculation unit (14, 16, 20, 22) calculates the lateral acceleration (α ｙ ) by the vehicle speed (V) ｙ / V) to the rotational angular velocity (ω ｙａｗ ) is subtracted from the differential side slip angle (dβ) to obtain the estimated side slip angle (β ｅｓｔ ) is calculated, The sideslip angle estimated value calculation unit (14, 16, 20, 22) calculates a sideslip angle differential value (dβ) calculated when the vehicle is traveling straight before the vehicle starts turning, by subtracting an offset error (dβ ０ ), and the sideslip angle estimated value (β ｅｓｔ 2. The side slip angle calculation device according to claim 1, further comprising:

3. 3. The side slip angle calculation device according to claim 2, wherein the side slip angle estimated value calculation unit (14, 16, 20, 22) performs band pass filtering on the side slip angle differential value (dβ).

4. The sideslip angle estimated value calculation unit (14, 16, 20, 22) performs band-pass filtering on the sideslip angle differential value (dβ) by calculating at least the lateral acceleration (α ｙ ) and rotational angular velocity (ω ｙａｗ 4. The side slip angle calculation device according to claim 3, further comprising a band pass filter process for the above-mentioned.

5. A determination unit (26) is provided for determining whether the vehicle is turning, The parameter calculation unit (28) calculates an estimated vehicle side slip angle (β ｅｓｔ ) and the vehicle speed (V) and rotational angular velocity (ω ｙａｗ ) and the multiplication result (Vω ｙａｗ ) are respectively identified (S200, S210), and the identified vehicle side slip angle estimate value (β ｅｓｔ ) and the vehicle speed (V) and rotational angular velocity (ω ｙａｗ ) and the multiplication result (Vω ｙａｗ 5. The side slip angle calculation device according to claim 1, further comprising: a step of calculating a parameter (K) based on the maximum value of the above-mentioned parameter (K) and the above-mentioned parameter (K) (S220).

6. A determination unit (26) is provided for determining whether the vehicle is turning, The side slip angle estimated value calculation unit (14, 16, 20, 22) calculates the side slip angle estimated value (β ｅｓｔ ) is calculated multiple times (S300, S310), The multiplication unit (24) multiplies the side slip angle estimated value (β ｅｓｔ ) is calculated, the vehicle speed (V) and the rotational angular velocity (ω ｙａｗ ) and the multiplication result (Vω ｙａｗ ) is calculated multiple times (S320), The parameter calculation unit (28) calculates the side slip angle estimated value (β ｅｓｔ ), vehicle speed (V) and rotational angular velocity (ω ｙａｗ ) and the multiplication result (Vω ｙａｗ 5. The side slip angle calculation device according to claim 1, further comprising: a step of calculating a plurality of parameters (K) based on the above-mentioned (S330); and calculating a parameter (K) from a most frequently occurring value of the plurality of parameters (K) or an average value after excluding outliers (S340).

7. A determination unit (26) is provided for determining whether the vehicle is turning, The parameter calculation unit (28) calculates the estimated sideslip angle (β ｅｓｔ ) and the multiplication result (Vω ｙａｗ ) and an adaptive filter (32) is applied to one of the sideslip angle estimated value (β ｅｓｔ ) and the multiplication result (Vω ｙａｗ 5. The side slip angle calculation device according to claim 1, further comprising: a transfer function of the adaptive filter that is adjusted so as to approximate the other of the first and second sideslip angles, and the parameter (K) is calculated from the adjusted transfer function.

8. 8. The side slip angle calculation device according to claim 5, wherein the parameter calculation unit (28) calculates the parameter (K) on the condition that a vehicle speed (V) of the turning vehicle is equal to or lower than a predetermined reference speed (S130).

9. 8. The sideslip angle calculation device according to claim 5, wherein the parameter calculation unit (28) is configured such that, when the vehicle sideslip angle calculated based on the calculated parameter (K) exceeds a predetermined upper limit value, the calculated parameter (K) is not used for calculating the vehicle sideslip angle (S180).

10. A road surface condition determination unit (36) for determining the condition of a road surface on which a vehicle is traveling; a parameter storage unit (38) that stores the parameter (K) calculated by the parameter calculation unit or updates the stored parameter (K) according to the road surface condition determined by the road surface condition determination unit; 8. The sideslip angle calculation device according to claim 5, wherein a parameter (K) corresponding to a road surface condition is selected from the parameters (K) stored in the parameter storage unit, and the vehicle sideslip angle is calculated based on the selected parameter (K).

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