Physical quantity detection device

Abstract

The present invention provides a physical quantity detection device capable of detecting load information including not only a vehicle weight, but also a passenger and a load weight, and lateral acceleration for each wheel, capable of performing independent damper control on four wheels, and capable of providing a lateral force with high calculation accuracy. A physical quantity detection device according to the present invention calculates a lateral force from a load detected in real time by a strain sensor and a lateral direction G detected from a sensor signal waveform characteristic, the load being detected on the basis of the magnitude of a strain peak amplitude. The lateral direction (G) is detected on the basis of the difference between the magnitude of the strain peak amplitude during steering (when the lateral direction (G) is applied) and the magnitude of the strain peak amplitude during straight movement.

Description

Technical Field The present invention relates to a physical quantity detection device for detecting lateral acceleration, lateral force, etc. acting on a tire. Background Art In recent years, tire sensor technology, which uses information from tires to detect factors such as road surface slipperiness and loads applied to the tires, has been actively developed to achieve safer driving conditions toward autonomous driving. This is because providing safer driving conditions can prevent accidents caused by tire failures such as blowouts due to overloading, or understeer due to reduced tire grip. Improving ride comfort through suspension control and other methods is also an important safety factor. Building such safety control systems requires highly accurate detection of physical quantities such as load and lateral acceleration detected by tire sensors. Tire strain sensors can detect tire load and lateral acceleration by monitoring tire strain and deformation. They can also estimate lateral force based on the load and lateral acceleration information. This is expected to improve driving safety by preventing vehicle failures and accidents. Strain sensors detect changes in various physical quantities (such as vehicle speed, temperature, air pressure, load, and lateral acceleration) as strain. Therefore, the detection signal (strain signal) representing the strain produced by the strain sensor may contain components derived from these other physical quantities. When detecting a specific physical quantity based on its correspondence with the strain signal, these components can reduce the detection accuracy of the specific physical quantity. Patent Document 1 listed below describes a technique for improving ride comfort using a suspension. The document describes the following technology: "A suspension control device for controlling the movement of a suspension of a vehicle, comprising: an operation-induced state quantity estimating unit that estimates an operation-induced state quantity representing a movement caused by the operation of the vehicle; a road surface-induced state quantity estimating unit that estimates a road surface-induced state quantity representing a movement caused by the road surface of the vehicle; an operation-induced state quantity converting unit that converts the operation-induced state quantity into an operation-induced required damping force; a road surface-induced state quantity converting unit that converts the road surface-induced state quantity into a road surface-induced required damping force; and a current value calculating unit that uses the operation-induced required damping force and the road surface-induced required damping force to determine the current value applied to the suspension. The device employs a mechanism for performing damper control based on the operation-induced state quantity (vehicle behavior caused by sudden acceleration or steering by the driver) to improve ride comfort and handling. The damper control is obtained based on longitudinal force and lateral force. For example, the lateral force is calculated based on F (lateral force) = m (mass) × a (lateral acceleration)." Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 2022-84474. Summary of the Invention Problems to be solved by the invention The technology described in Patent Document 1 employs a mechanism that improves ride comfort and handling by controlling shock absorbers based on operational state quantities (vehicle behavior caused by sudden acceleration or steering by the driver). This shock absorber control is calculated based on longitudinal and lateral forces. For example, the lateral force is calculated based on F (lateral force) = m (mass) × a (lateral acceleration). However, since the mass m used in the calculation of the lateral force F is the vehicle body weight stored in memory, the loads of the passengers and cargo are omitted, and the calculation accuracy of the lateral force may be poor. In addition, it is expected that the shock absorber control can independently control the four wheels, but since the lateral force is calculated based on the acceleration of the vehicle's center of gravity and a fixed vehicle weight value, there is a concern that the lateral force cannot be calculated based on the load borne by each of the four wheels. Therefore, it can be considered that the technology described in this document has room for improvement in the calculation accuracy of the lateral force. In view of the above circumstances, an object of the present invention is to provide a physical quantity detection device for lateral force that can provide independent lateral forces on four wheels and can provide high calculation accuracy. Technical means to solve the problem A representative overview of the inventions disclosed in this application is briefly described below. One aspect of the present invention is a physical quantity detection device that detects at least one of lateral G or lateral force acting on the tire using a strain sensor mounted on a tire. The device is characterized by comprising: a load detection calculation unit that detects a load applied to the tire based on a negative peak value of a sensor signal waveform output by the strain sensor that changes negatively relative to a reference level when the tire is not in contact with the road surface; a lateral G detection calculation unit that distinguishes between the sensor signal waveform when the tire is traveling straight and the sensor signal waveform when the tire is turning, and detects the lateral G acting on the tire based on the amount of change in the negative peak value of the sensor signal waveform that changes negatively relative to the reference level when the tire is not in contact with the road surface; and a lateral force detection calculation unit that detects the lateral force acting on the tire based on the product of the load detected by the load detection calculation unit and the lateral G detected by the lateral G detection calculation unit. Effects of the Invention The physical quantity detection device according to the present invention can estimate load based on the negative peak value of the strain signal output by the sensor element, which changes in a negative direction relative to a reference level. It can also estimate lateral G (lateral acceleration) based on the change in the signal waveform between the negative peak value during straight driving and when the tire is turning. Furthermore, based on this load and lateral G (lateral acceleration), lateral force can be estimated using the formula: lateral force F = detected load m × lateral acceleration a. In other words, load and lateral G can be detected for each strain sensor installed on the tire, enabling high-precision lateral force detection based on real-time load and lateral G to achieve four-wheel independent system control. More features related to the present invention will become clear through the description of this specification and the accompanying drawings. In addition, other issues, structures and effects than those described above will become clear through the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a diagram showing the configuration of a vehicle equipped with the physical quantity detection device according to the first embodiment. Figure 2 It is a diagram showing the configuration of the physical quantity detection device according to the first embodiment. Figure 3 This is an explanatory diagram showing sensor signal waveforms of the strain sensor corresponding to the tire rotation state in the first embodiment. Figure 4 This is a waveform diagram showing the waveform of the sensor signal of the strain sensor corresponding to the tire rotation state in the first embodiment. Figure 5 This is an explanatory diagram showing the waveform of a sensor signal of the strain sensor in one cycle in the first embodiment. Figure 6A This is an explanatory diagram showing a schematic diagram of lateral G detection in the first embodiment (outline of lateral G of the right front wheel during a left turn). Figure 6B This is an explanatory diagram showing a schematic diagram of lateral G detection (sensor signal waveform of the strain sensor during left turn) in the first embodiment. Figure 7 This is an explanatory diagram showing the relationship among the reference waveform, the load estimation waveform, and the lateral G detection waveform in the first embodiment. Figure 8 This is a flowchart for deriving a table of parameters mixed in the sensor signal waveform of the strain sensor in the first embodiment. Figure 9 This is an explanatory diagram of a speed correlation table showing the correlation between the correction amount of the negative-level peak value of the sensor signal waveform of the strain sensor and the speed in the first embodiment. Figure 10This is an explanatory diagram of a temperature correlation table showing the correlation between the correction amount of the negative-level peak value of the sensor signal waveform of the strain sensor and the temperature in the first embodiment. Figure 11 This is an explanatory diagram of an air pressure correlation table showing the correlation between the correction amount of the negative-level peak value of the sensor signal waveform of the strain sensor and the air pressure in the first embodiment. Figure 12 It is an explanatory diagram showing a table including various tables in the first embodiment. Figure 13 This is a flowchart for estimating the load and the lateral G based on the sensor signal waveform of the strain sensor in the first embodiment. Figure 14 This is the result of verifying the feasibility of strain sensor load estimation in the first embodiment. Figure 15 This is an explanatory diagram showing a first table of parameters mixed in the sensor signal waveform of the strain sensor in the first embodiment. Figure 16 This is the result of verifying the feasibility of the strain sensor lateral G estimation in the first embodiment. Figure 17 It is a diagram showing the configuration of a physical quantity detection device according to the second embodiment. Figure 18A This is an explanatory diagram showing an overview of lateral G detection in the second embodiment (outline of lateral G of the right front wheel during a left turn). Figure 18B It is an explanatory diagram showing an outline of lateral G detection (sensor signal waveform of the strain sensor 1 during left turn) in the second embodiment. Figure 18C This is an explanatory diagram showing an overview of lateral G detection (sensor signal waveform of the strain sensor 2 during left turn) in the second embodiment. Figure 19 It is a diagram showing the configuration of a physical quantity detection device according to a third embodiment. Figure 20A This is an explanatory diagram showing the arrangement structure of the strain sensors in the third embodiment (outline of the lateral G of the left front wheel during right turn). Figure 20B This is an explanatory diagram showing the arrangement structure of the strain sensors in the third embodiment (outline of the lateral G of the right front wheel during left turn). Figure 21 This is a flowchart showing how lateral force detection information from a strain sensor is used for shock absorber control in a fourth embodiment. Figure 22A This is a diagram illustrating the grip force achieved by the damper control executed based on lateral force information in the fourth embodiment (the grip force decreases when there is no damper control). Figure 22B This is a diagram illustrating the grip achieved by the damper control executed based on lateral force information in the fourth embodiment (the grip is improved when the damper control is performed). DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. In addition, in all drawings used to illustrate the embodiments, identical components are, in principle, given the same reference numerals, and their repeated descriptions are omitted. The present invention is not limited to the descriptions of the embodiments shown below. It will be readily understood by those skilled in the art that the specific configurations may be modified without departing from the spirit or purpose of the present invention. In this specification, etc., references such as "first," "second," and "third" are used to identify components and do not necessarily limit their number or order. Furthermore, the numbers used to identify components are context-dependent, and a number used in one context does not necessarily indicate the same structure in another context. Furthermore, this does not prevent a component identified by one number from performing the functions of a component identified by another number. The positions, sizes, shapes, and ranges of various components shown in the drawings and the like may not represent actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings and the like. In this specification, constituent elements expressed in the singular are intended to include the plural form unless the context clearly indicates otherwise. [First embodiment] <Overall Vehicle Structure> Figure 1 FIG. 1 is a diagram showing the configuration of a vehicle 100 equipped with the physical quantity detection device 10 according to the first embodiment. Figure 1 As shown, the vehicle 100 includes four tires 101, an ECU 102, and a reporting unit 103. The vehicle 100 includes four temperature sensors 2 and four strain sensors 3. Figure 3 ) can be a four-wheeled vehicle, a two-wheeled vehicle or a three-wheeled vehicle, or a vehicle with more than five wheels. The vehicle 100 travels on the road surface 20 by the rotation of four tires 101. A person is on board the vehicle 100. The tire 101 contacts the road surface 20 and bears the load of the vehicle 100. The tire 101 rotates. The tire 101 is a rubber member. The ECU 102 is a control unit that controls the vehicle 100 . The ECU 102 includes a processing unit, a storage unit, various sensors, a processing unit such as a CPU, and input / output ports electrically connected to a storage unit such as a memory and a reporting unit 103 . The notification unit 103 is a monitor for the in-vehicle navigation system. The display screen of the notification unit 103 switches between the navigation screen and the screen reporting lateral G, lateral force, etc., based on interrupt processing from the ECU 102. The display screen of the notification unit 103 is controlled based on the control of the ECU 102. The temperature sensor 2 obtains the temperature of each tire 101 and outputs it to the ECU 102. The strain sensor 3 as a sensor element obtains a sensor signal waveform 15 ( Figure 3 , etc.), and outputs it to the ECU 102. In addition, the strain sensor 3 may be substituted for the temperature sensor 2 to detect the temperature of each tire 101. <Physical Quantity Detection Device 10> Figure 2 This figure shows the configuration of a physical quantity detection device 10 according to the first embodiment. Physical quantity detection device 10 is associated with a safe driving support system for a vehicle 100, and is particularly used to prevent accidents caused by insufficient braking control, etc., by providing a safe driving state. Physical quantity detection device 10 detects loads and lateral G, etc., which affect the durability and grip of tires 101 mounted on vehicle 100. like Figure 2 As shown, the physical quantity detection device 10 includes a strain sensor 3, a lateral G detection calculation unit 4, a storage unit 411, a load detection calculation unit 6, a lateral force detection calculation unit 7, and a reporting unit 103. The physical quantity detection device 10 detects the lateral G and lateral force of the tire 101 based on the output signal waveform. Furthermore, the physical quantity detection device 10 is independently installed on each of the four tires 101, and the lateral G or lateral force of each tire is shared by the shared reporting unit 103 for system control. Strain sensor 3 The strain sensor 3 is a sensor element. The strain sensor 3 is a semiconductor that converts the strain corresponding to the resistance change and outputs it. One strain sensor 3 is configured on each tire 101. The strain sensor 3 outputs a sensor signal waveform 15 ( ) having a reference level 151, a positive level that changes in a positive direction relative to the reference level 151, and a negative level that changes in a negative direction relative to the reference level 151. Figure 3 wait). <Lateral G Detection Calculation Unit 4> The lateral G detection calculation unit 4 functions as the lateral G detection calculation unit 4 by executing a program in the ECU 102. The lateral G detection calculation unit 4 receives the sensor signal waveform 15 output by the strain sensor 3. The lateral G detection calculation unit 4 obtains the temperature of the tire 101 from the temperature sensor 2. It obtains the speed by dividing the tire's outer circumference by the output period of the sensor signal waveform 15. Alternatively, the lateral G detection calculation unit 4 can obtain the speed from a speed sensor, etc. The lateral G detection calculation unit 4 corrects the sensor signal waveform 15 output by the strain sensor 3 based on the obtained parameters such as temperature and speed, and estimates lateral G and other factors based on the difference between this corrected signal and a reference waveform (reference value) stored in the storage unit 411. The lateral G detection calculation unit 4 transmits the estimated lateral G and other factors to the reporting unit 103 and the lateral force detection calculation unit 7. The lateral G detection calculation unit 4 includes a correction unit 412 and a lateral G calculation unit 413 . Storage unit 411 stores a reference waveform (positive peak value, negative peak value, reference level) acquired under reference conditions (air pressure, temperature, speed) of sensor signal waveform 15 output by strain sensor 3, as well as a first table 5 showing the amount of change for each parameter condition. The acquired data is, for example, data on an asphalt road surface. Correction unit 412 determines whether a lateral G force has occurred based on the difference between the negative peak values ​​of sensor signal waveform 15 during straight travel and during turning, and extracts the lateral G component. Furthermore, correction unit 412 can correct the signal waveform under specified conditions based on the values ​​of first table 5 stored in storage unit 411 to offset differences between the reference conditions and the parameters of the air pressure, velocity, and temperature, which are confounding signals mixed in sensor signal waveform 15. Correction unit 412 transmits the extracted lateral G component to lateral G calculation unit 413. Lateral G calculation unit 413 compares the positive peak value 152, the negative peak value 153, and the reference level 151 of the lateral G component signal transmitted from correction unit 412 with the relevant characteristics under the various parameter conditions in first Table 5 stored in storage unit 411, and estimates lateral G based on the difference in characteristics from negative peak value 153. Lateral G calculation unit 413 transmits the estimated lateral G to reporting unit 103 and lateral force detection calculation unit 7. <Load detection calculation unit 6> The load detection calculation unit 6 functions as the lateral G detection calculation unit 4 by executing a program in the ECU 102. The load detection calculation unit 6 receives the sensor signal waveform 15 output by the strain sensor 3. The load detection and calculation unit 6 , similar to the lateral G detection and calculation unit 4 , includes a load correction unit 611 and a load calculation unit 612 . As described in the lateral G detection calculation unit 4, the storage unit 411 stores a reference waveform (positive peak value, negative peak value, reference level) acquired under reference conditions (air pressure, temperature, speed) of the sensor signal waveform 15 output by the strain sensor 3, as well as a first table 5 of changes for each parameter condition. This first table 5 is shared for use in the correction calculation. Load correction unit 611 calculates the correction amount based on the peak value of the negative level of sensor signal waveform 15 during straight travel. Furthermore, load correction unit 611 corrects the signal waveform under specified conditions based on the values ​​of first table 5 stored in storage unit 411 to offset the difference between the parameters of the mixed signal, namely, air pressure, speed, and temperature, mixed in the sensor signal waveform 15 and the reference conditions. Load correction unit 611 then transmits the corrected signal waveform to load calculation unit 612. Load calculation unit 612 compares the positive peak value 152, the negative peak value 153, and the reference level 151 of the correction signal waveform transmitted by load correction unit 611 with the relevant characteristics under the various parameter conditions in first Table 5 stored in storage unit 411. Load calculation unit 612 estimates the load based on the difference in characteristics from negative peak value 153. Load calculation unit 612 transmits the estimated load to lateral force detection calculation unit 7. <Lateral force detection calculation unit 7> The lateral force detection calculation unit 7 estimates the lateral force by multiplying the load estimated by the load detection calculation unit 6 by the lateral G estimated by the lateral G detection calculation unit 4. The lateral force detection calculation unit 7 transmits the estimated lateral force to the reporting unit 103. <Sensor signal waveform 15> Figure 3 1 is an explanatory diagram showing a sensor signal waveform 15 of the strain sensor 3 corresponding to the rotation state of the tire 101 in the first embodiment. Figure 3 As shown, the strain sensor 3 disposed inside the tire 101 outputs a sensor signal waveform 15 that changes according to the state of the rotating tire 101 . The strain sensor 3 outputs a sensor signal waveform 15 having a reference level 151 , a positive level that changes in a positive direction relative to the reference level 151 , and a negative level that changes in a negative direction relative to the reference level 151 . When the tire 101 is not in contact with the road surface 20, the strain sensor 3 maintains a reference level 151 of the sensor signal waveform 15. When the tire 101 (the portion where the strain sensor 3 is located) is in contact with the road surface 20, the strain sensor 3 outputs a positive peak level 152 of the sensor signal waveform 15. At the moment when the tire 101 (the portion where the strain sensor 3 is located) contacts or separates from the road surface 20, the strain sensor 3 outputs a negative peak level 153 of the sensor signal waveform 15. Here, the moment when the tire 101 contacts or separates from the road surface 20 is referred to as a sensor displacement point. The period between these two sensor displacement points is the contact period when the tire 101 (the portion where the strain sensor 3 is located) contacts the road surface 20. The sensor signal waveform 15 detected in this way changes depending on various physical quantities (load, air pressure, speed, temperature). Figure 4 1 is a waveform diagram showing the sensor signal waveform 15 of the strain sensor 3 corresponding to the rotation state of the tire 101 in the first embodiment. Figure 4 As shown, as the tire 101 rotates, the sensor signal waveform 15 of the strain sensor 3 repeats a reference level 151, a negative level that changes in a negative direction relative to the reference level 151, a positive level that changes in a positive direction relative to the reference level 151, and a negative level that changes in a negative direction relative to the reference level 151. The signal value of the sensor signal waveform 15 can be represented by a signal amplitude. Figures 3 and 4 The sensor signal waveform 15 is also represented by the signal amplitude. The signal amplitude mentioned here can be any value that represents the vibration amplitude of the sensor signal waveform 15. The sensor signal waveform 15 has the following characteristics: Figure 5 The waveform shown has a falling waveform before and after the rising waveform. For example, the amplitude of the second falling waveform can be treated as the amplitude of the sensor signal waveform 15. This is the premise for the following. Figure 5 1 is an explanatory diagram showing a sensor signal waveform 15 of the strain sensor 3 in one cycle in the first embodiment. Figure 5 yes Figure 4 A magnified view of part A. Figure 5 As shown, the reference level 151 includes pressure (air pressure) information, the positive level peak (sometimes recorded as positive peak) 152 includes wear information, and the negative level peak (sometimes recorded as negative peak) 153 includes load and lateral G information. <Horizontal G detection diagram (outline)> Figure 6A 、 Figure 6B : is an explanatory diagram showing a schematic diagram of lateral G detection. Figure 6AAs shown, the tire 101 mainly includes a sidewall portion 111 and a tread portion 112, and a strain sensor 3 is arranged inside the surface (tire tread) of the tread portion 112 (tire inner surface), especially on the outer side of the center of the tire inner surface of the tire tread. Figure 6B The sensor signal waveform 15 of the strain sensor 3 during a left turn is shown. The mechanism is that the negative level peak value increases when switching from straight driving to turning, and the lateral G is detected based on the correlation between this increase and the lateral G amount. Figure 7 This is an explanatory diagram showing how the correction method for removing physical quantities mixed in the strain signal is applied to lateral G detection. Lateral G detection is represented by the difference peak between the negative level peak when traveling straight and when turning. First, in order to obtain the load, the reference waveform is compared with the correction waveform when the load increases to detect the load. At this time, the mixed physical quantities (air pressure, temperature, vehicle speed) are removed by correction, and only the load information is extracted. Next, the straight-line waveform when the load increases and the waveform when turning are compared, from which the mixed signals are removed, and the lateral G component is extracted from the difference. Therefore, by obtaining the difference between the physical quantities mixed in the strain signal contained in the peaks when turning and when traveling straight, they can be offset. In addition, in order to obtain the lateral force, load information is required, and in order to detect the load with high precision, it is necessary to perform correction processing to offset the mixed signals. <Method for preparing Table 5> Figure 8 This is a flowchart for deriving the first table 5 in the first embodiment, which stores the peak correlation between the sensor signal waveform 15 of the strain sensor 3 and the negative level under various conditions including the reference condition. like Figure 8 As shown, in S101, a control unit (not shown) that generates a table controls the vehicle 100 to drive straight and turn under reference atmospheric pressure, temperature, speed, load, and lateral G, and acquires the output of the strain sensor 3 relative to the reference conditions. For load detection, the peak value of the negative level during straight driving is used as the reference waveform. For lateral G detection, the difference between the peak values ​​of the negative level during straight driving and during turning is defined as the reference waveform. In S102 , the control unit obtains a change relationship between the negative level peak 153 of the sensor signal waveform 15 of the strain sensor 3 and the reference waveform when the vehicle 100 is traveling while changing the reference air pressure, temperature, speed, load, and lateral G. In S103 , the control unit stores the reference waveform of the sensor signal waveform 15 acquired in S102 and the amount of change thereof in the first table 5 . When various conditions change, changes in sensor signal waveform 15 do not necessarily need to be represented using differences from a reference or a baseline signal value. However, because the absolute values ​​of the signal values ​​vary for each vehicle model or tire type, data identical to that in first table 5 would need to be created in advance for each absolute value, significantly increasing the amount of data. Therefore, describing the data using differences from the reference value reduces the amount of data. The values ​​of air pressure, temperature, speed, etc. are changed in advance, and the correlation between the negative level peak 153 of the sensor signal waveform 15 of the strain sensor 3 and the air pressure, temperature, speed, etc. is stored in the storage unit 411 as a table. Figure 9 This is an explanatory diagram showing a first table 5 of the first embodiment, which shows the correlation between the correction amount of the negative-level peak 153 of the sensor signal waveform 15 of the strain sensor 3 and the speed. Figure 9 The table shown acquires the following correlation: as the speed increases, the correction amount of the negative-level peak 153 of the sensor signal waveform 15 becomes larger. Figure 10 This is an explanatory diagram showing a temperature correlation table of the first table 5 in the first embodiment, which shows the correlation between the correction amount of the negative-level peak 153 of the sensor signal waveform 15 of the strain sensor 3 and the temperature. Figure 10 The table shown acquires the following correlation: as the temperature becomes higher, the correction amount of the negative-level peak 153 of the sensor signal waveform 15 becomes larger. Figure 11 This is an explanatory diagram showing the air pressure correlation table of the first table 5 in the first embodiment, which shows the correlation between the correction amount at the negative level peak 153 of the sensor signal waveform 15 of the strain sensor 3 and the air pressure. Figure 11 The table shown acquires the following correlation: as the air pressure becomes higher, the correction amount of the negative-level peak 153 of the sensor signal waveform 15 becomes smaller. Figure 12 : is an explanatory diagram showing the first table 5 including various tables in the first embodiment. Figure 12 As shown, the first table 5 includes the reference table of the first embodiment and Figures 9 to 11 Therefore, for the vehicle 100 traveling in various situations, the correction amount for load detection and lateral G detection is estimated based on the first table 5 stored in the storage unit 411 for the negative level peak 153 of the sensor signal waveform 15 output by the strain sensor 3. <Horizontal G detection method> Figure 13This is a flowchart for estimating the load and the lateral G of the tire 101 during travel based on the sensor signal waveform 15 of the strain sensor 3 in the first embodiment. Figure 13 The flowchart of the load and lateral G detection method shown is repeatedly executed at a fixed cycle while the vehicle 100 is traveling. When the load and lateral G detection method is implemented, in S201, the lateral G detection calculation unit 4 uses the calibration unit 412 to confirm the driving conditions of the vehicle 100 during its driving state. The driving conditions are those that match the driving conditions used to derive the first table 5. After the calibration unit 412 confirms the driving conditions in S201, the process moves to S202. In S202, a correction signal waveform for load estimation is obtained based on the waveform during straight travel. To correct the sensor signal waveform 15 output by the strain sensor 3 to a signal waveform having the same reference conditions as the reference waveform, the load detection calculation unit 6 calculates a correction amount from the correlation diagram of air pressure, temperature, and speed derived from the first table 5. This correction amount is then subtracted from the output sensor signal waveform 15 to obtain the corrected signal waveform. After S202, the process moves to S203. In S203, the load detection calculation unit 6 estimates the load based on the comparison of the correction signal waveform obtained in S202 with the reference waveform. First, the difference between the correction signal waveform at the negative peak and the reference waveform is compared with the load correlation diagram in Table 5. The load corresponding to this difference is estimated for each occurrence. The load is transmitted to the lateral force detection calculation unit 7. After S203, the process moves to S204. In S204, the correction unit 412 performs a lateral G determination. The difference between the negative peak 153 of the sensor signal waveform 15 during straight travel and during turning is checked. If the difference changes by 10% or more, it is determined that a lateral G has occurred, and the process moves to S205. If not, the acquisition of straight travel data continues. In S205, the lateral G detection calculation unit 4 compares the negative peak 153 of the sensor signal waveform 15 detected by the strain sensor 3 during straight driving with the negative peak 153 during turn determination. Furthermore, since the difference between straight driving and turn detection is taken during lateral G detection, aliasing signals are canceled out, eliminating the need for correction. After S205, the process moves to S206. In S206, the difference between the reference waveform during steering and the negative peak 153 of the sensor signal waveform 15 is first determined. This difference is then compared with the lateral G correlation diagram in Table 5, and the lateral G corresponding to the difference is estimated. Furthermore, the lateral force calculated is estimated based on the estimated lateral G and the load estimated in S203. The lateral G and lateral force are transmitted to the reporting unit 103. After S206, the process is temporarily terminated. Verification of the lateral G detection method The verification of the load detection method and the lateral G detection method are described in turn. Figure 14 This is an example of the actual sensor signal waveform based on the strain sensor 3 in the first embodiment. Figure 13 The flow chart shows the results of verifying the feasibility of load estimation. Figure 14 The load sensitivity of the negative peak 153 in the sensor signal waveform 15 of the strain sensor 3 for reference conditions (air pressure, temperature, and speed) is shown. The speed sensitivity is also shown. It can be seen that the negative peak 153 decreases linearly (monotonically) as the load increases, indicating that the first table 5 shown in the flowchart can be constructed. Furthermore, it can be confirmed that the speed changes at a nearly constant value relative to the load. Figure 15 1 is an explanatory diagram showing the first table 5 of the parameters mixed in the sensor signal waveform 15 of the strain sensor 3 in the first embodiment. Figure 15 As shown, the correlation diagram of air pressure, temperature, and speed in Table 5 shows a proportional curve with the same correlation with the sensor signal waveform 15 regardless of load changes. This is because air pressure, temperature, and speed are insensitive to load and appear as constant values. Table 5 is stored in storage unit 411. Table 5 derives the actual required load line by subtracting the correction values ​​for various physical quantities mixed in the air pressure correction, speed correction, and temperature correction lines from the line of the apparent reference level 151 of the sensor signal waveform 15. Figure 16 This is an example of a sensor signal waveform based on actual measurement of the strain sensor 3 in the first embodiment. Figure 13 Flowchart showing the results of verifying the feasibility of lateral G estimation. Figure 16 The figure shows the transverse G sensitivity of the negative level peak 153 in the sensor signal waveform 15 of the strain sensor 3 relative to the reference condition. It can be seen that as the transverse G increases, the difference of the negative level peak 153 decreases linearly (monotonically), which indicates that the first table 5 shown in the flowchart can be constructed. In addition, Figure 16In the figure, the difference between the lateral G and the peak value 153 of the negative level (the difference between the peak values ​​when going straight and when turning) decreases linearly (decreases monotonically), but the same applies to the case where the difference between the lateral G and the peak value 153 of the negative level (the difference between the peak values ​​when going straight and when turning) increases linearly (increases monotonically). Effects As described above, the sensor signal waveform 15 output by the strain sensor 3 is corrected based on parameters such as air pressure, temperature, and speed. The load is estimated based on the difference between this corrected signal waveform and the reference waveform (reference value) stored in the storage unit 411. Furthermore, the lateral G is estimated based on the difference (change) between the sensor signal waveform 15 during straight driving and during turning. This allows the strain sensor 3 to detect both the load and the lateral G. Furthermore, the lateral force can be detected based on the product of the load and the lateral G. [Second embodiment] The following describes a modified embodiment of the above embodiment. A device is described that employs the first embodiment's configuration by adding two strain sensors within the tire to detect lateral G. Since the overall vehicle configuration is identical to the first embodiment, its description will be omitted. Physical Quantity Detection Device 2010 Figure 17 This figure shows the configuration of a physical quantity detection device 2010 according to the second embodiment. Physical quantity detection device 2010 is associated with a safe driving assistance system for vehicle 100, and is particularly used to prevent accidents caused by insufficient braking control, etc., by providing a safe driving state. Physical quantity detection device 2010 detects factors such as load and lateral G that affect the durability and grip of tires 101 mounted on vehicle 100. like Figure 17 As shown, physical quantity detection device 2010 includes strain sensor 1 2003, strain sensor 2 2031, lateral G detection calculation unit 2004, storage unit 2411, load detection calculation unit 2006, lateral force detection calculation unit 2007, and reporting unit 2103. Physical quantity detection device 2010 detects the lateral G and lateral force of tire 101 based on the output signal waveform. The configuration and operation of the lateral G detection calculation unit 2004 and the load detection calculation unit 2006 are the same as those in the first embodiment, and thus their description is omitted. Furthermore, the table creation method and the lateral G detection method are also the same as those in the first embodiment, and thus their description is omitted. <Horizontal G detection diagram (outline)> Figure 18A 、 Figure 18B 、 Figure 18C : is an explanatory diagram showing a schematic diagram of lateral G detection. Figure 18A As shown, strain sensor 1 2003 is arranged on the inner side (tire inner surface) of the surface (tire tread) of tread portion 112, and strain sensor 2 2031 is arranged on the outer side. In other words, strain sensor 1 2003 and strain sensor 2 2031 are arranged on the inner surface of the tire tread, separated left and right (center). Figure 18B The sensor signal waveform of the strain sensor 1 2003 when turning left is shown. Figure 18C Figure 2 shows the sensor signal waveform of strain sensor 2 2031. In the inner strain sensor 1 2003, the negative peak decreases when the vehicle switches from straight driving to turning, while in the outer strain sensor 2 2031, the negative peak increases when the vehicle switches from straight driving to turning. By taking the difference between this increase and decrease, the amount of negative peaks can be increased. The correlation between this increase and the amount of lateral G can be used to detect lateral G with high sensitivity. Effects As described above, the lateral G is obtained by calculating the correlation between the difference in the negative level peak value of the sensor signal waveform of the two strain sensors arranged left and right in the tire, and the further increment of the peak value when going straight and turning (in other words, the further difference in the negative level peak value (the change in the increased part and the decreased part) of the two strain sensors arranged left and right in the tire when going straight and turning) and the lateral G amount. In addition to the effect of the first embodiment, it also has the effect of improving the sensitivity of lateral G detection. [Third embodiment] The following describes a modified embodiment of the above-mentioned embodiment. Regarding a device that employs the second embodiment's configuration of additionally placing two strain sensors within the tire to detect lateral G, a method is described. This method utilizes a single strain sensor within the tire, while the other strain sensor for differential measurement is located in one of the left and right tires. Since the overall vehicle structure is the same as in the first embodiment, its description will be omitted. <Physical Quantity Detection Devices 3010 and 4010> Figure 19This diagram shows the configuration of a physical quantity detection device 13010 for the left tire and a physical quantity detection device 24010 for the right tire according to a third embodiment. The device receives strain sensor signals from both physical quantity detection devices as second sensor signals, which are then received by lateral G detection calculation units 13004 and 24004. Physical quantity detection devices 13010 and 24010 are associated with a safe driving assistance system for vehicle 100, and are particularly used to prevent accidents caused by insufficient braking control, etc., by providing a safe driving state. Physical quantity detection devices 13010 and 24010 detect loads and lateral G forces that affect the durability and grip of tires 101 mounted on vehicle 100. like Figure 19 As shown, the physical quantity detection device 13010 for the left tire includes a strain sensor 13003, a lateral G detection calculation unit 13004, a storage unit 13411, a load detection calculation unit 13006, a lateral force detection calculation unit 13007, and a reporting unit 3103. The physical quantity detection device 13010 detects the lateral G and lateral force of the left tire 101 based on the output signal waveform. The configuration and operation of the lateral G detection calculation unit 13004 and the load detection calculation unit 13006 are the same as those in the first embodiment, and thus their description is omitted. Furthermore, the table creation method and the lateral G detection method are also the same as those in the first embodiment, and thus their description is omitted. Similar to the left tire physical quantity detection device 13010, the right tire physical quantity detection device 24010 includes a strain sensor 24003, a lateral G detection calculation unit 24004, a storage unit 24411, a load detection calculation unit 24006, a lateral force detection calculation unit 24007, and a reporting unit 3103. The physical quantity detection device 24010 detects the lateral G and lateral force of the right tire 101 based on the output signal waveform. The configuration and operation of the lateral G detection calculation unit 2 4004 and the load detection calculation unit 2 4006 are the same as those in the first embodiment, and thus their description is omitted. Furthermore, the table creation method and the lateral G detection method are also the same as those in the first embodiment, and thus their description is omitted. <Horizontal G detection diagram (outline)> Figure 20A 、 Figure 20B This is an explanatory diagram showing the configuration of strain sensors in the left and right tires. Figure 20A As shown, a strain sensor 13003 is arranged on the outside of the inner portion (inner surface) of the surface (tire tread) of the tread portion 112 of the left tire, as shown in FIG. Figure 20BAs shown in FIG. 4 , a strain sensor 2 4003 is arranged on the outside of the inner side (inner side) of the tread portion 112 of the right tire. The method is to detect the lateral G ( Figure 20B ), the lateral G is determined based on the peak value of the signal waveform obtained by subtracting the sensor signal waveform of the strain sensor 1 3003 from the sensor signal waveform of the strain sensor 2 4003; for the lateral G acting on the left front wheel when turning right ( Figure 20A ), the lateral G is determined based on the peak value of the signal waveform obtained by subtracting the sensor signal waveform of the strain sensor 2 4003 from the sensor signal waveform of the strain sensor 1 3003. Thus, similar to the second embodiment, the peak value can be increased, and the detection sensitivity of the lateral G can be improved. Effects As described above, the lateral G is obtained by calculating the correlation between the difference in the negative level peak value of the sensor signal waveform of the strain sensors arranged on the inner and outer sides of the left and right tires, and the further increment of the peak value when going straight and when turning (in other words, the further difference in the difference (change) in the negative level peak value of the (2) strain sensors respectively arranged in the left and right tires when going straight and when turning) and the lateral G amount. In addition to the effect of the first embodiment, it also has the effect of improving the sensitivity of lateral G detection. [Fourth embodiment] The following describes a modified embodiment of the above embodiment. A method for improving tire grip by performing damper control using the lateral force estimated in the first embodiment is described below. Because the overall vehicle structure is the same as in the first embodiment, its description is omitted. Furthermore, the physical quantity detection device, table creation method, and lateral G detection method are also the same as in the first embodiment, and their description is omitted. Figure 21 This is a flowchart for estimating the lateral force of the tire 101 running based on the sensor signal waveform 15 of the strain sensor 3 and further performing shock absorber control in the fourth embodiment. Figure 21 The flowchart of the lateral force detection and shock absorber control method is repeatedly executed at a certain period while the vehicle 100 is traveling. Compared with the first embodiment Figure 13 Similarly, steps S401 to S406 are executed, and after the lateral G is determined, the process moves to S407. In S407, the shock absorber of the tire on the side generating the lateral force G is controlled to have a damping force corresponding to the lateral force. After the control and the processing of S407, the processing is temporarily terminated. Figure 22A 、 Figure 22BThis diagram schematically illustrates the improvement in grip achieved by damper control based on lateral force information. Figure 22A The diagram shows the mechanism of grip loss when no damper control is applied. This figure illustrates a situation where a vehicle turns left and generates a lateral G in the right direction. In this situation, the lateral G shifts the center of gravity of the vehicle to the right, causing the vehicle to tilt rightward. This concentrates the vehicle's weight on the right tire, generating a greater lateral force than normal, potentially rendering the normal tire grip insufficient. Furthermore, the reduced weight on the left tire generates a force that causes the tire to lift off the road, potentially reducing grip. Figure 22B This diagram illustrates the mechanism for improving grip when damper control is in effect. Similarly, it illustrates the situation where a vehicle turns left and experiences a rightward lateral G. In this situation, the vehicle's center of gravity tends to shift rightward due to the lateral G, but damper control maintains the right-side damping force at a level appropriate to the magnitude of the lateral G, reducing the degree of tilt compared to a situation without damper control. This prevents the vehicle's weight from concentrating on the right tire, achieving weight balance across all four wheels and increasing the likelihood that normal grip can be used to support the vehicle. Furthermore, by also balancing the vehicle's weight on the left tire, the force that could cause the tire to lift off the road is reduced, thereby minimizing a loss in grip. Effects As described above, by performing suspension control or damper control based on the lateral G or lateral force detected by the strain sensor 3 and changing the balance of tire grip, there is an effect of increasing the possibility of suppressing a decrease in tire grip. [Summary of the First to Fourth Embodiments] As described above, the physical quantity detection device 10, 2010, 3010, 4010 of the present embodiment is a physical quantity detection device 10, 2010, 3010, 4010 that detects at least one of the lateral G or lateral force acting on the tire 101 from a strain sensor provided on the tire 101, and comprises: a load detection operation unit 6 that detects the load applied to the tire 101 based on a negative peak value (a peak value of a negative level) 153 of a sensor signal waveform 15 output by the strain sensor that changes in a negative direction relative to a reference level 151 in a state in which the tire 101 is not in contact with the road surface 20; a lateral G detection operation unit 4 that determines whether the tire 101 is in contact with the road surface 20; The sensor signal waveform 15 when the tire 101 is moving straight and the sensor signal waveform 15 when the tire 101 is turning, and the lateral G acting on the tire 101 is detected based on the negative peak value (peak value of the negative level) 153 of the sensor signal waveform 15 that changes in a negative direction relative to the reference level 151 when the tire 101 is not in contact with the road surface 20, according to the change (difference) of the sensor signal waveform when the tire 101 is moving straight and when the tire 101 is turning; and a lateral force detection operation unit 7, which detects the lateral force acting on the tire 101 based on the product of the load detected by the load detection operation unit 6 and the lateral G detected by the lateral G detection operation unit 4. The strain sensor is arranged on the outer side of the center of the inner surface of the tire tread. The difference (amount of change) between the negative peak values ​​of the sensor output waveform 15 when the tire 101 is traveling straight and when turning monotonically increases or decreases with respect to the lateral G. Two strain sensors are disposed on the inner surface of the tire tread, one on each side. The lateral G detection calculation unit 2004 further determines the difference between the negative peak values ​​(negative level peak values) 153 of the two strain sensors and the change in the sensor signal waveform when the tire 101 is traveling straight and when turning, and detects the lateral G based on the difference (second embodiment). One of the two strain sensors is disposed outside the center of the inner surface of the tire tread, and the other is disposed inside the center of the inner surface of the tire tread (second embodiment). The lateral G detection calculation unit 4 stores the lateral G sensitivity characteristics of the strain peak stored in the storage units 411, 2411, 3411, and 4411 of the physical quantity detection devices 10, 2010, 3010, and 4010 as a table (first table 5), and detects the lateral G by comparing it with the lateral G sensitivity characteristics of the strain peak. The physical quantity detection device 10 , 2010 , 3010 , 4010 can also detect the air pressure of the tire 101 using the reference level 151 of the sensor signal waveform 15 , and detect the load and wear of the tire 101 based on the strain signal corrected by the air pressure. The strain sensor is arranged on the inner surface of the tire tread of the tire 101 (left and right front wheels) arranged on the left and right front sides of the vehicle, and the lateral G detection operation units 3004 and 4004 obtain the further difference of the negative peak value (peak value of the negative level) 153 of the (2) strain sensors respectively arranged on the tires 101 (left and right front wheels) arranged on the left and right front sides of the vehicle, and the change (difference) of the sensor signal waveform when the tire 101 is moving straight and when turning, and detect the lateral G based on the difference (third embodiment). When the change (difference) of the negative peak (negative level peak) 153 between the tire 101 running straight and turning is equal to or greater than 10% of the signal amplitude of the sensor signal waveform, the lateral G detection operation unit 4 determines that the lateral G has occurred. The lateral G detection calculation unit 4 continuously compares the characteristics with those stored in a table (first table 5 ) to detect the lateral G in real time. The physical quantity detection devices 10 , 2010 , 3010 , and 4010 are used to improve the ride comfort of a vehicle equipped with the tire 101 by controlling the suspension based on the magnitude of the lateral G. The physical quantity detection devices 10 , 2010 , 3010 , and 4010 are used for safety assistance, which changes the balance of the gripping force of the tire 101 by controlling the shock absorber based on the magnitude of the lateral force, thereby preventing the vehicle equipped with the tire 101 from skidding. The physical quantity detection devices 10, 2010, 3010, and 4010 according to the present embodiments can estimate load based on the negative peak of the strain signal output by the sensor element, which changes negatively relative to a reference level. Lateral G (lateral acceleration) can also be estimated based on the change in the signal waveform between the negative peak and the negative peak when the tire is traveling straight and turning. Furthermore, lateral force can be estimated based on the load and lateral G (lateral acceleration) using the formula: lateral force F = detected load m × lateral acceleration a. In other words, load and lateral G can be detected for each strain sensor installed on the tire, enabling high-precision lateral force detection based on real-time load and lateral G to achieve four-wheel independent system control. The present invention is not limited to the above-described embodiments and encompasses various variations. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention and are not necessarily limited to having all the structures described. Furthermore, portions of the structure of one embodiment may be replaced with structures of another embodiment, and structures of another embodiment may be added to the structure of one embodiment. Furthermore, portions of the structure of each embodiment may be added to, deleted from, or replaced with structures of another embodiment. Explanation of symbols 2…temperature sensor, 3…strain sensor, 4…lateral G detection calculation unit, 5…first table, 6…load detection calculation unit, 7…lateral force detection calculation unit, 10…physical quantity detection device, 15…sensor signal waveform, 100…vehicle, 101…tire, 102…ECU, 103…reporting unit, 151…reference level, 152…peak value of positive level, 153…peak value of negative level, 411…storage unit, 412…calibration unit, 413…lateral G calculation unit, 611…load calibration unit, 612…load calculation unit.

Claims

1. A physical quantity detection device that detects at least one of lateral G or lateral force acting on a tire using a strain sensor provided on the tire, the physical quantity detection device comprising: a load detection calculation unit configured to detect a load applied to the tire based on a negative peak value of a sensor signal waveform output by the strain sensor that changes in a negative direction relative to a reference level indicating a state in which the tire is not in contact with the road surface; a lateral G detection calculation unit that distinguishes the sensor signal waveform when the tire is traveling straight and the sensor signal waveform when the tire is turning, and detects the lateral G acting on the tire between the straight travel and the turning based on the amount of change in the sensor signal waveform between the negative peak value of the sensor signal waveform that changes in a negative direction relative to the reference level in a state where the tire is not in contact with the road surface; and A lateral force detection calculation unit detects a lateral force acting on the tire based on a product of the load detected by the load detection calculation unit and the lateral G detected by the lateral G detection calculation unit.

2. The physical quantity detection device according to claim 1, characterized in that The strain sensor is arranged on the outer side of the center of the inner surface of the tire tread.

3. The physical quantity detection device according to claim 1, wherein The difference between the negative peak values ​​of the sensor output waveform when the tire is traveling straight and when turning monotonically increases or decreases with respect to the lateral G.

4. The physical quantity detection device according to claim 1, wherein The strain sensors are provided in two positions on the left and right sides of the inner surface of the tire tread. The lateral G detection calculation unit obtains a difference between the amount of change in the sensor signal waveforms of the negative peak values ​​of the two strain sensors when the tire is traveling straight and when the tire is turning, and detects the lateral G based on the difference.

5. The physical quantity detection device according to claim 1, wherein The lateral G detection calculation unit stores the lateral G sensitivity characteristics of the strain peak stored in the storage unit included in the physical quantity detection device as a table, and detects the lateral G by comparing with the lateral G sensitivity characteristics of the strain peak.

6. The physical quantity detection device according to claim 1, wherein The physical quantity detection device can also detect the air pressure of the tire using the reference level of the sensor signal waveform, and detect the load and wear of the tire based on the strain signal corrected using the air pressure.

7. The physical quantity detection device according to claim 1, wherein The strain sensor is provided on the inner surface of the tire tread of the tire arranged on the left and right sides of the front side of the vehicle. The lateral G detection calculation unit further determines the difference between the change in the negative peak of the sensor signal waveform of the strain sensors respectively provided on the left and right tires arranged on the front side of the vehicle when the tire is traveling straight and when the tire is turning, and detects the lateral G based on the difference.

8. The physical quantity detection device according to claim 1, wherein The lateral G detection calculation unit determines that the lateral G has occurred when the amount of change in the negative peak value when the tire is traveling straight and when turning is equal to or greater than 10% of the signal amplitude of the sensor signal waveform.

9. The physical quantity detection device according to claim 1, wherein The lateral G detection calculation unit continuously compares the characteristics with those stored in a table to detect the lateral G in real time.

10. The physical quantity detection device according to claim 1, wherein This invention is used to improve the ride comfort of a vehicle equipped with the tire by controlling the suspension based on the magnitude of the lateral G.

11. The physical quantity detection device according to claim 1, wherein This is applied to safety assistance for changing the balance of the force of the tire gripping the road by controlling the shock absorber based on the magnitude of the lateral force, thereby preventing the vehicle equipped with the tire from skidding.

12. The physical quantity detection device according to claim 4, characterized in that One of the two strain sensors is disposed on the outer side of the center of the inner surface of the tire tread, and the other of the two strain sensors is disposed on the inner side of the center of the inner surface of the tire tread.

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