Tire grounding mark length testing method and device

Abstract

The invention discloses a tire grounding mark length testing method and device, and relates to the field of tire grounding mark length testing. According to the method, the grounding data and the circumferential strain curve of the tire are obtained through the strain waveform data of the tire movement in combination with the flexible tire body model, and then the grounding angle of the tire is obtained, so that the grounding mark length of the tire is determined in combination with the geometric radius of the tire. By exploring the relation between the grounding angle and the grounding mark length in the tire movement process and excavating the coupling relation between radial deformation and tangential deformation of the tire body circular ring, the accuracy of the grounding mark length is improved. Through the strain waveform data of the tire and by taking the circumferential strain as a medium, the calculation step of the length of the grounding mark is simplified, and the testing efficiency of the length of the grounding mark is improved, so that the performance of the tire can be evaluated and improved based on the length of the grounding mark of the tire, and the driving safety and performance of an automobile are improved.

Description

Technical Field

[0001] The invention belongs to the field of tire contact patch length testing, and in particular relates to a tire contact patch length testing method and device. Background Art

[0002] With the continuous development of society, the number of cars is also increasing. In the composition of cars, tires are an indispensable part. As the contact part between the car and the ground, they not only bear the weight of the car, but also affect the safety and handling of the car. Therefore, it is necessary to test the tire rolling data such as the tire footprint length and sinking amount during the driving process of the car, so as to better improve the car tires.

[0003] At present, the test of tire rolling data mainly relies on large dynamic footprint testers, which can monitor a lot of information about the contact between the tire and the ground, including parameters such as the contact footprint length and the amount of sinking. However, due to the complex equipment of the dynamic footprint tester, the operation convenience is poor, and the high requirements for the tire testing environment, it is impossible to quickly and accurately test the tire's contact footprint length; in addition, different types of tires have adaptation problems for the dynamic footprint tester, which makes it impossible for the dynamic footprint tester to better test the accurate contact footprint length of different types of tires under complex working conditions. Therefore, there is an urgent need for a tire contact footprint length testing method and system to solve the defects of the existing technology. Summary of the invention

[0004] The present invention aims to provide a method and device for testing the tire contact patch length to solve the above-mentioned technical problems, process the strain waveform data of the tire movement, realize the test of the tire contact patch length, and improve the test efficiency and accuracy of the tire contact patch length.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a method for testing the tire contact footprint length, comprising:

[0006] Collect strain waveform data of tire movement;

[0007] Determining a tire circumferential strain curve according to the strain waveform data and in combination with a preset flexible carcass model;

[0008] Determining the contact angle of the tire according to the circumferential strain curve and a preset sampling rate;

[0009] The geometric radius of the tire is obtained, and combined with the contact angle, the contact footprint length of the tire is determined.

[0010] It can be understood that, compared with the prior art, the present invention obtains the contact data and circumferential strain curve of the tire through the strain waveform data of the tire movement, combined with the flexible carcass model, and then obtains the contact angle of the tire, thereby determining the contact footprint length of the tire in combination with the geometric radius of the tire. By exploring the relationship between the contact angle and the contact footprint length during the movement of the tire, and exploring the coupling relationship between the radial deformation and the tangential deformation of the tire carcass ring, the accuracy of the contact footprint length is improved. The circumferential strain of the tire ring is derived through the tire strain waveform data, and then the contact footprint length of the tire is calculated. With the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the test efficiency of the contact footprint length is improved, so that the performance of the tire can be evaluated and improved based on the contact footprint length of the tire, thereby improving the driving safety and performance of the vehicle.

[0011] As a preferred solution, the step of determining the tire circumferential strain curve based on the strain waveform data and in combination with a preset flexible carcass model specifically includes:

[0012] Determine the contact area and non-contact area of ​​the tire according to the strain waveform data and in combination with a preset flexible carcass model;

[0013] A circumferential strain curve is determined according to the contact area and the non-contact area in combination with the flexible carcass model and strain waveform data.

[0014] This preferred solution uses strain waveform data combined with a flexible carcass model to fully explore the coupling relationship between the radial deformation and tangential deformation of the tire carcass ring in the strain waveform data, thereby obtaining the contact area and non-contact area, and then obtaining the circumferential strain curve. Using the circumferential strain as the medium, the steps for obtaining the contact patch length are simplified, and the testing efficiency of the contact patch length is improved.

[0015] As a preferred solution, the circumferential strain curve is determined according to the contact area and non-contact area in combination with the flexible carcass model and the strain waveform data, specifically including:

[0016] According to the contact area and the non-contact area, in combination with the strain waveform data, a plurality of circumferential strain inflection points are obtained;

[0017] According to the circumferential strain inflection point and in combination with the flexible carcass model, a circumferential strain curve is determined.

[0018] This preferred solution is based on the circumferential strain inflection point and combines with the flexible carcass model to obtain an accurate circumferential strain curve, which provides a basis for the subsequent determination of the tire's contact patch length based on the circumferential strain curve, explores the coupling relationship between the radial deformation and tangential deformation of the tire carcass ring, and improves the accuracy of the contact patch length.

[0019] As a preferred solution, the method of determining the contact angle of the tire according to the circumferential strain curve in combination with a preset sampling rate specifically includes:

[0020] Determine the number of points in the contact area and the non-contact area according to the circumferential strain curve;

[0021] The contact angle of the tire is determined according to the number of points in the contact area and the non-contact area in combination with a preset sampling rate.

[0022] This preferred solution determines the number of points in the contact area and the non-contact area through the circumferential strain curve, and then determines the contact angle of the tire in combination with the sampling rate, so that the contact footprint length of the tire can be calculated based on the circumferential strain curve. Using the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the testing efficiency of the contact footprint length is improved.

[0023] As a preferred solution, determining the number of points in the contact area and the non-contact area according to the circumferential strain curve specifically includes:

[0024] According to the abscissa value of the circumferential strain inflection point of the contact area in the circumferential strain curve, the number of points in the contact area is obtained;

[0025] The number of points in the non-contact area is obtained according to the abscissa value of the circumferential strain inflection point in the non-contact area in the circumferential strain curve.

[0026] This preferred solution determines the number of points in the contact area and the non-contact area through the horizontal coordinate value of the circumferential strain inflection point, and then determines the contact angle of the tire in combination with the sampling rate, so that the contact footprint length of the tire can be calculated based on the circumferential strain curve. Using the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the testing efficiency of the contact footprint length is improved.

[0027] As a preferred solution, the method of determining the contact angle of the tire according to the number of points in the contact area and the non-contact area in combination with a preset sampling rate specifically includes:

[0028] Determine the touchdown time and cycle time according to the number of points in the touchdown area and the non-touchdown area in combination with a preset sampling rate;

[0029] Determining a tire contact ratio according to the contact time and the cycle time;

[0030] The contact angle of the tire is determined according to the contact ratio and the angle corresponding to the cycle time.

[0031] This preferred solution determines the accurate tire contact angle, so that the tire contact patch length can be calculated based on the tire contact angle, which simplifies the steps for obtaining the contact patch length and improves the testing efficiency of the contact patch length.

[0032] As a preferred solution, the step of obtaining the geometric radius of the tire and determining the contact patch length of the tire in combination with the contact angle specifically includes:

[0033] Get the geometric radius of the tire and combine it with the contact angle to determine the contact footprint length of the tire:

[0034]

[0035] Among them, C l is the contact patch length of the tire, a is the half length of the tire contact, R is the geometric radius of the tire, and Δφ is the tire contact angle.

[0036] This preferred solution can obtain the contact patch length of the tire through the geometric radius of the tire combined with the contact angle. Through a simple calculation process, the steps for obtaining the contact patch length are simplified, and the test efficiency of the contact patch length is improved. The accurate contact patch length is obtained by using the tire's own equipment data, so that the performance of the tire can be evaluated and improved, ensuring the safety and performance of the vehicle.

[0037] As a preferred solution, it also includes:

[0038] According to the geometric radius, combined with the contact angle, the tire sinkage is determined:

[0039]

[0040] Among them, l is the tire sinkage, R is the geometric radius of the tire, and Δφ is the tire contact angle.

[0041] This preferred solution can obtain the tire's sinking amount through the tire's geometric radius combined with the contact angle, so that the tire's performance can be comprehensively evaluated and improved based on the sinking amount and contact footprint length, thereby ensuring the safety and performance of the vehicle.

[0042] Accordingly, an embodiment of the present invention provides a tire contact patch length testing device, comprising: a data acquisition module, a circumferential strain curve construction module, a contact angle calculation module, and a contact patch length testing module;

[0043] Wherein, the data acquisition module is used to collect strain waveform data of tire movement;

[0044] The circumferential strain curve construction module is used to determine the tire circumferential strain curve according to the strain waveform data in combination with a preset flexible carcass model;

[0045] The contact angle calculation module is used to determine the contact angle of the tire according to the circumferential strain curve in combination with a preset sampling rate;

[0046] The contact patch length testing module is used to obtain the geometric radius of the tire and determine the contact patch length of the tire in combination with the contact angle.

[0047] As a preferred solution, the contact footprint length test module comprises: a contact footprint length test unit;

[0048] The contact patch length testing unit is used to obtain the geometric radius of the tire and determine the contact patch length of the tire in combination with the contact angle:

[0049]

[0050] Among them, C l is the contact patch length of the tire, a is the half length of the tire contact, R is the geometric radius of the tire, and Δφ is the tire contact angle.

[0051] It can be understood that, compared with the prior art, this system obtains the tire's contact data and circumferential strain curve through the strain waveform data of the tire movement, combined with the flexible carcass model, and then obtains the tire's contact angle, thereby determining the tire's contact footprint length in combination with the tire's geometric radius. By exploring the relationship between the contact angle and the contact footprint length during the tire's movement, and exploring the coupling relationship between the radial deformation and tangential deformation of the tire carcass ring, the accuracy of the contact footprint length is improved. Through the tire's strain waveform data, the circumferential strain of the tire ring is derived, and then the tire's contact footprint length is calculated. Using the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the test efficiency of the contact footprint length is improved, so that the tire's performance can be evaluated and improved based on the tire's contact footprint length, thereby improving the driving safety and performance of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 : A flow chart of steps of a method for testing tire contact patch length provided by an embodiment of the present invention;

[0053] Figure 2 : A schematic diagram of dividing a tire contact area and a non-contact area provided by an embodiment of the present invention;

[0054] Figure 3 : A schematic diagram of a tire grounding provided by an embodiment of the present invention;

[0055] Figure 4 : A schematic structural diagram of a tire contact footprint length testing device provided by an embodiment of the present invention;

[0056] Figure 5 : A connection diagram of an intelligent tire system provided by an embodiment of the present invention;

[0057] Figure 6 : A circuit schematic diagram of a strain sensor provided by an embodiment of the present invention;

[0058] Among them, 201: data acquisition module; 202: circumferential strain curve construction module; 203: grounding angle calculation module; 204: grounding footprint length test module; 301: strain sensor; 302: wire; 303: acquisition and transmission module; 304: tire section; VCC: power supply node; RS: first resistor; Vout: output node; R0: second resistor; GND: ground node. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] Tires are an indispensable part of cars. As the part that contacts the ground, they not only bear the weight of the car, but also affect the safety and handling of the car. Therefore, it is necessary to test the tire rolling data such as the tire footprint length and sinking amount during the driving process of the car, so as to better improve the car tires.

[0061] The existing ability to monitor the length of dynamic tire footprints mainly relies on large dynamic footprint testing machines, which can monitor a lot of information about the contact between the tire and the ground, including ground footprint length, ground stress distribution and other parameters. However, the dynamic footprint testing machine has many equipment mechanisms, a messy layout, and a lack of industrial design, resulting in poor operational convenience; it can only be used for rolling tests of tires under low-speed driving conditions, and it is necessary to install pressure-sensitive paper on the frame or use a camera, which makes it difficult to continuously capture instantaneous ground footprints, resulting in increased testing costs; the testing machine can only move in the vertical direction, and for tires of different specifications, the loading accuracy is difficult to guarantee, the product adaptability is weak, and the footprint can only show the tread part, and the performance under complex working conditions cannot be demonstrated.

[0062] In addition, the prior art also has a set of tire dynamic footprint length testing equipment built by mechanical parts, which is mainly composed of a transparent plate, a base, a first drive mechanism and a photographic device. It can simulate the ground contact shape, ground contact pressure distribution and other issues under the dynamic changes of the tire during driving of the vehicle to a certain extent; however, this method is based on camera equipment to collect data and perform simulations, and is not accurate enough for the test of the ground contact footprint length.

[0063] Others have achieved continuous capture of tire instantaneous imprints by optimizing equipment functions, and achieved functions such as applying precise radial loads to tires of different speeds and specifications. However, this method can only capture tires in low-speed motion and cannot adapt well to the movement of tires in different complex situations.

[0064] Another method is to improve the equipment by installing a rotating motor, controlling the angle between the swing seat and the fixed seat, so that the radial center plane of the tire forms a certain angle with the vertical plane, thereby being able to monitor the tire footprint and pressure distribution with an inclination angle. However, this method is too complicated during the test process, resulting in relatively low efficiency.

[0065] Embodiment 1

[0066] Please refer to Figure 1 , is a flowchart of a method for testing tire contact footprint length provided by an embodiment of the present invention, including steps S101-S104.

[0067] Step S101: collecting strain waveform data of tire movement.

[0068] Step S102: determining a tire circumferential strain curve according to the strain waveform data and in combination with a preset flexible carcass model.

[0069] In this embodiment, the tire circumferential strain curve is determined based on the strain waveform data in combination with a preset flexible carcass model, specifically including:

[0070] Determine the contact area and non-contact area of ​​the tire according to the strain waveform data and in combination with a preset flexible carcass model;

[0071] A circumferential strain curve is determined according to the contact area and the non-contact area in combination with the flexible carcass model and strain waveform data.

[0072] Through strain waveform data and combined with the flexible carcass model, the coupling relationship between the radial deformation and tangential deformation of the tire carcass ring in the strain waveform data is fully explored, so as to obtain the contact area and non-contact area, and then obtain the circumferential strain curve. Using the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the test efficiency of the contact footprint length is improved.

[0073] It should be noted that the preset flexible carcass model refers to a flexible carcass model based on analytical elasticity, including a flexible ring model, FTire model or CDTire model, etc., which are used to study tire morphology. The flexible carcass model used in this application is a flexible ring model.

[0074] In an optional embodiment, determining the contact area and non-contact area of ​​the tire according to the strain waveform data in combination with a preset flexible carcass model specifically includes:

[0075] According to the strain waveform data, combined with a preset flexible carcass model, the strain waveform in the strain waveform data is divided to obtain the ground contact moment and the ground lift moment;

[0076] According to the contact moment and lift-off moment, the contact area and non-contact area of ​​the tire are determined.

[0077] In this embodiment, the circumferential strain curve is determined according to the contact area and the non-contact area in combination with the flexible carcass model and the strain waveform data, specifically including:

[0078] According to the contact area and the non-contact area, in combination with the strain waveform data, a plurality of circumferential strain inflection points are obtained;

[0079] According to the circumferential strain inflection point and in combination with the flexible carcass model, a circumferential strain curve is determined.

[0080] Based on the circumferential strain inflection point and combined with the flexible carcass model, an accurate circumferential strain curve was obtained, which provided a basis for the subsequent calculation of the tire contact footprint length based on the circumferential strain curve, explored the coupling relationship between the radial deformation and tangential deformation of the tire carcass ring, and improved the accuracy of the contact footprint length.

[0081] In an alternative embodiment, please refer to Figure 2 , is a schematic diagram of dividing a tire contact area and a non-contact area provided by an embodiment of the present invention, such as Figure 2 As shown in the figure, the ordinate is the strain AD value, the abscissa is the data sequence value, the solid line is the contact area, and the dotted line is the non-contact area; the intersection point between the solid line and the dotted line is the circumferential strain inflection point, that is, the position where the circumferential strain slope changes the most; wherein, the circumferential strain of the tire is affected by the circumferential deformation, and in the transition area between the contact area and the non-contact area, the curvature of the deformed part is the smallest, resulting in a sudden change in the circumferential strain, which corresponds to the position of the leading edge and the trailing edge of the tire contact area.

[0082] Step S103: determining the contact angle of the tire according to the circumferential strain curve and a preset sampling rate.

[0083] In this embodiment, determining the contact angle of the tire according to the circumferential strain curve in combination with a preset sampling rate specifically includes:

[0084] Determine the number of points in the contact area and the non-contact area according to the circumferential strain curve;

[0085] The contact angle of the tire is determined according to the number of points in the contact area and the non-contact area in combination with a preset sampling rate.

[0086] The number of points in the contact area and the non-contact area is determined by the circumferential strain curve, and then the contact angle of the tire is determined in combination with the sampling rate. Therefore, the contact footprint length of the tire can be calculated based on the circumferential strain curve. Using the circumferential strain as the medium simplifies the steps for obtaining the contact footprint length and improves the testing efficiency of the contact footprint length.

[0087] In this embodiment, determining the number of points in the contact area and the non-contact area according to the circumferential strain curve specifically includes:

[0088] According to the abscissa value of the circumferential strain inflection point of the contact area in the circumferential strain curve, the number of points in the contact area is obtained;

[0089] The number of points in the non-contact area is obtained according to the abscissa value of the circumferential strain inflection point in the non-contact area in the circumferential strain curve.

[0090] The number of points in the contact area and the non-contact area is determined by the horizontal coordinate value of the circumferential strain inflection point, and then the contact angle of the tire is determined in combination with the sampling rate, so that the contact patch length of the tire can be calculated based on the circumferential strain curve. Using the circumferential strain as the medium, the steps for obtaining the contact patch length are simplified, and the test efficiency of the contact patch length is improved.

[0091] In an alternative embodiment, if Figure 2 As shown, the number of points in the contact area is obtained according to the difference in the horizontal coordinates of the two circumferential strain inflection points before and after the contact area; the number of points in the non-contact area is obtained according to the difference in the horizontal coordinates of the two circumferential strain inflection points before and after the non-contact area.

[0092] In this embodiment, the determining of the contact angle of the tire according to the number of points in the contact area and the non-contact area in combination with a preset sampling rate specifically includes:

[0093] Determine the touchdown time and cycle time according to the number of points in the touchdown area and the non-touchdown area in combination with a preset sampling rate;

[0094] Determining a tire contact ratio according to the contact time and the cycle time;

[0095] The contact angle of the tire is determined according to the contact ratio and the angle corresponding to the cycle time.

[0096] By determining the accurate tire contact angle, the tire contact patch length can be calculated based on the tire contact angle, which simplifies the steps for obtaining the contact patch length and improves the test efficiency of the contact patch length.

[0097] In an optional embodiment, determining the contact ratio of the tire according to the contact time and the cycle time specifically includes:

[0098] Grounding ratio = grounding time / cycle time.

[0099] It should be noted that the touchdown time can be derived from the touchdown points, and the cycle time can be derived from the cycle points. The cycle points can be obtained according to the division of the touchdown area and the non-touchdown area as shown in Figure 2; the angle corresponding to the cycle time is 360° in one circle.

[0100] Step S104: Obtain the geometric radius of the tire, and determine the contact patch length of the tire in combination with the contact angle.

[0101] Please refer to Figure 3 , is a schematic diagram of tire grounding provided by an embodiment of the present invention.

[0102] In this embodiment, if Figure 3 As shown, the step of obtaining the geometric radius of the tire and determining the contact patch length of the tire in combination with the contact angle specifically includes:

[0103] Get the geometric radius of the tire and combine it with the contact angle to determine the contact footprint length of the tire:

[0104]

[0105] Among them, C l is the contact patch length of the tire, a is the half length of the tire contact, R is the geometric radius of the tire, and Δφ is the tire contact angle.

[0106] The tire's contact patch length can be obtained through the tire's geometric radius and the contact angle. A simple calculation process simplifies the steps for obtaining the contact patch length and improves the test efficiency of the contact patch length. The accurate contact patch length is obtained based on the tire's own equipment data, so that the tire's performance can be evaluated and improved, ensuring the safety and performance of the vehicle.

[0107] In this embodiment, if Figure 3 As shown, it also includes:

[0108] According to the geometric radius, combined with the contact angle, the tire sinkage is determined:

[0109]

[0110] Among them, l is the tire sinkage, R is the geometric radius of the tire, and Δφ is the tire contact angle.

[0111] The tire's geometric radius and contact angle can be used to determine the tire's sinkage, which enables a comprehensive evaluation and improvement of the tire's performance based on the sinkage and contact patch length, thereby ensuring the safety and performance of the vehicle.

[0112] This embodiment uses the strain waveform data of the tire movement, combined with the flexible carcass model, to obtain the tire's contact data and circumferential strain curve, and then obtains the tire's contact angle, thereby determining the tire's contact footprint length in combination with the tire's geometric radius. By exploring the relationship between the contact angle and the contact footprint length during tire movement, and exploring the coupling relationship between the radial deformation and tangential deformation of the tire carcass ring, the accuracy of the contact footprint length is improved. The circumferential strain of the tire ring is derived through the tire's strain waveform data, and then the tire's contact footprint length is calculated. Using the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the test efficiency of the contact footprint length is improved, so that the tire's performance can be evaluated and improved based on the tire's contact footprint length, thereby improving the driving safety and performance of the vehicle.

[0113] Embodiment 2

[0114] Please refer to Figure 4 , is a schematic structural diagram of a tire contact patch length testing device provided by an embodiment of the present invention, comprising: a data acquisition module 201, a circumferential strain curve construction module 202, a contact angle calculation module 203, and a contact patch length testing module 204;

[0115] The data acquisition module 201 is used to acquire strain waveform data of tire movement.

[0116] The circumferential strain curve construction module 202 is used to determine the tire circumferential strain curve according to the strain waveform data in combination with a preset flexible carcass model.

[0117] In this embodiment, the circumferential strain curve construction module 202 includes: a circumferential strain curve construction unit;

[0118] The circumferential strain curve construction unit is used to determine the contact area and non-contact area of ​​the tire according to the strain waveform data in combination with a preset flexible carcass model;

[0119] A circumferential strain curve is determined according to the contact area and the non-contact area in combination with the flexible carcass model and strain waveform data.

[0120] In this embodiment, the circumferential strain curve construction unit includes: a circumferential strain curve construction subunit;

[0121] The circumferential strain curve construction subunit is used to obtain a plurality of circumferential strain inflection points according to the contact area and the non-contact area in combination with the strain waveform data;

[0122] According to the circumferential strain inflection point and in combination with the flexible carcass model, a circumferential strain curve is determined.

[0123] The contact angle calculation module 203 is used to determine the contact angle of the tire according to the circumferential strain curve in combination with a preset sampling rate.

[0124] In this embodiment, the touchdown angle calculation module 203 includes: a touchdown angle calculation unit;

[0125] The contact angle calculation unit is used to determine the number of points in the contact area and the non-contact area according to the circumferential strain curve;

[0126] The contact angle of the tire is determined according to the number of points in the contact area and the non-contact area in combination with a preset sampling rate.

[0127] In this embodiment, the touchdown angle calculation unit includes: a point number calculation subunit;

[0128] The point number calculation subunit is used to obtain the number of points in the contact area according to the horizontal coordinate value of the circumferential strain inflection point of the contact area in the circumferential strain curve;

[0129] The number of points in the non-contact area is obtained according to the abscissa value of the circumferential strain inflection point in the non-contact area in the circumferential strain curve.

[0130] In this embodiment, the touchdown angle calculation unit includes: a touchdown angle calculation subunit;

[0131] The touchdown angle calculation subunit is used to determine the touchdown time and cycle time according to the number of points in the touchdown area and the non-touchdown area in combination with a preset sampling rate;

[0132] Determining a tire contact ratio according to the contact time and the cycle time;

[0133] The contact angle of the tire is determined according to the contact ratio and the angle corresponding to the cycle time.

[0134] The contact patch length testing module 204 is used to obtain the geometric radius of the tire and determine the contact patch length of the tire in combination with the contact angle.

[0135] In this embodiment, the contact patch length testing module 204 includes: a contact patch length testing unit;

[0136] The contact patch length testing unit is used to obtain the geometric radius of the tire and determine the contact patch length of the tire in combination with the contact angle:

[0137]

[0138] Among them, C l is the contact patch length of the tire, a is the half length of the tire contact, R is the geometric radius of the tire, and Δφ is the tire contact angle.

[0139] In this embodiment, the contact footprint length test module 204 includes: a sinking amount test unit;

[0140] The sinking amount testing unit is used to determine the sinking amount of the tire according to the geometric radius and the contact angle:

[0141]

[0142] Among them, l is the tire sinkage, R is the geometric radius of the tire, and Δφ is the tire contact angle.

[0143] In an alternative embodiment, please refer to Figure 5 , is a connection diagram of an intelligent tire system provided by an embodiment of the present invention, including: a strain sensor 301, a wire 302 and a collection and transmission module 303;

[0144] Among them, the strain sensor 301, the wire 302 and the acquisition and transmission module 303 are connected in sequence;

[0145] The acquisition and transmission module 303 includes: a fixed-value voltage-dividing resistor, an ADC module, an air pressure sensor, a Bluetooth module, an antenna, a battery and a rubber sleeve.

[0146] In an alternative embodiment, if Figure 5 As shown, the intelligent tire system further includes: a tire section 304;

[0147] The tire section 304 is used as a carrier for the strain sensor 301 , the wire 302 and the acquisition and transmission module 303 .

[0148] In an alternative embodiment, if Figure 5 As shown, the strain sensor 301 is a stretchable strain sensor, which is mainly used to monitor the motion form of the tire, with rubber as the substrate, including natural rubber and synthetic rubber. The sensor principle is a tensile resistance type, and the sensor resistance is linearly related to the elongation.

[0149] In an alternative embodiment, if Figure 5 As shown, the acquisition and transmission module 303 is used to acquire sensor signals and transmit the signals to the terminal via Bluetooth wireless; the wire 302 is used to transmit the strain waveform data acquired by the strain sensor 301 to the acquisition and transmission module 303 .

[0150] In an alternative embodiment, please refer to Figure 6 , is a circuit schematic diagram of a strain sensor provided by an embodiment of the present invention, including a power supply node VCC, a first resistor RS, an output node Vout, a second resistor R0 and a ground node GND;

[0151] The power node VCC, the first resistor RS, the second resistor R0 and the ground node GND are electrically connected in sequence; and the output node is electrically connected between the first resistor RS and the second resistor R0.

[0152] In an optional embodiment, the battery is an automotive-grade button battery, which is used to supply power to the acquisition and transmission module 303; the rubber sleeve is mainly used to carry the acquisition and transmission module 303, and is adhered to the inner surface of the tire by glue.

[0153] In an optional embodiment, the intelligent tire system further includes: a tire rolling tester;

[0154] The tire rolling tester is used to keep the tire at a preset inclination angle and deflection angle during rolling.

[0155] In an optional embodiment, the principle of the smart tire system is as follows:

[0156] First, place the acquisition and transmission module 303 in the rubber sleeve, glue the rubber sleeve with the acquisition and transmission module 303 to the inner surface of the tire, and glue the strain sensor 301 to the inner surface of the tire, and connect the acquisition and transmission module 303 and the strain sensor 301 with a wire;

[0157] Next, the tire with the rim is mounted on a rolling test machine, and the tire rolling test machine drives the tire to rotate. The strain waveform collected by the strain sensor 301 is transmitted to the computer terminal using the collection and transmission module 303 .

[0158] It should be noted that this intelligent tire system adopts the method of intelligent tires. By sticking strain sensors and acquisition and transmission modules on the inner liner of the tire and combining with a tire rolling tester, the deformation characteristics of the tire under any rolling state are obtained. Based on the flexible carcass model based on analytical elasticity, the coupling relationship between the radial deformation and the tangential deformation of the carcass ring is considered, and the strain waveform is divided into the contact area and the non-contact area. For the contact area of ​​the tire, the dynamic footprint length and dynamic sinking amount of the tire are obtained by using parameters such as rolling radius and contact angle, and the trigonometric function mathematical method is used.

[0159] This embodiment uses the strain waveform data of the tire movement, combined with the flexible carcass model, to obtain the tire's contact data and circumferential strain curve, and then obtains the tire's contact angle, thereby determining the tire's contact footprint length in combination with the tire's geometric radius. By exploring the relationship between the contact angle and the contact footprint length during tire movement, and exploring the coupling relationship between the radial deformation and tangential deformation of the tire carcass ring, the accuracy of the contact footprint length is improved. The circumferential strain of the tire ring is derived through the tire's strain waveform data, and then the tire's contact footprint length is calculated. Using the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the test efficiency of the contact footprint length is improved, so that the tire's performance can be evaluated and improved based on the tire's contact footprint length, thereby improving the driving safety and performance of the vehicle.

[0160] In summary, the embodiment of the present invention obtains the contact data and circumferential strain curve of the tire through the strain waveform data of the tire movement combined with the flexible carcass model, and then obtains the contact angle of the tire, thereby determining the contact footprint length of the tire in combination with the geometric radius of the tire. By exploring the relationship between the contact angle and the contact footprint length during the tire movement process, and exploring the coupling relationship between the radial deformation and the tangential deformation of the tire carcass ring, the accuracy of the contact footprint length is improved. The circumferential strain of the tire ring is derived through the tire strain waveform data, and then the contact footprint length of the tire is calculated. With the circumferential strain as the medium, the steps for obtaining the contact footprint length are simplified, and the test efficiency of the contact footprint length is improved, so that the performance of the tire can be evaluated and improved based on the contact footprint length of the tire, thereby improving the driving safety and performance of the vehicle.

[0161] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for testing tire contact patch length, characterized in that: include: Collect strain waveform data of tire movement; Determining a tire circumferential strain curve according to the strain waveform data and in combination with a preset flexible carcass model; Determining the contact angle of the tire according to the circumferential strain curve and a preset sampling rate; The geometric radius of the tire is obtained, and combined with the contact angle, the contact footprint length of the tire is determined.

2. A method for testing tire contact patch length as claimed in claim 1, characterized in that: Determining the tire circumferential strain curve according to the strain waveform data and in combination with a preset flexible carcass model specifically includes: Determine the contact area and non-contact area of ​​the tire according to the strain waveform data and in combination with a preset flexible carcass model; A circumferential strain curve is determined according to the contact area and the non-contact area in combination with the flexible carcass model and strain waveform data.

3. A method for testing tire contact patch length as claimed in claim 2, characterized in that: The step of determining the circumferential strain curve according to the contact area and non-contact area in combination with the flexible carcass model and the strain waveform data specifically includes: According to the contact area and the non-contact area, in combination with the strain waveform data, a plurality of circumferential strain inflection points are obtained; According to the circumferential strain inflection point and in combination with the flexible carcass model, a circumferential strain curve is determined.

4. A method for testing tire contact patch length as claimed in claim 3, characterized in that: Determining the contact angle of the tire according to the circumferential strain curve in combination with a preset sampling rate specifically includes: Determine the number of points in the contact area and the non-contact area according to the circumferential strain curve; The contact angle of the tire is determined according to the number of points in the contact area and the non-contact area in combination with a preset sampling rate.

5. A method for testing tire contact patch length as claimed in claim 4, characterized in that: Determining the number of points in the contact area and the non-contact area according to the circumferential strain curve specifically includes: According to the abscissa value of the circumferential strain inflection point of the contact area in the circumferential strain curve, the number of points in the contact area is obtained; The number of points in the non-contact area is obtained according to the abscissa value of the circumferential strain inflection point in the non-contact area in the circumferential strain curve.

6. A method for testing tire contact patch length according to any one of claims 4 or 5, characterized in that: The step of determining the contact angle of the tire according to the number of points in the contact area and the non-contact area in combination with a preset sampling rate specifically includes: Determine the touchdown time and cycle time according to the number of points in the touchdown area and the non-touchdown area in combination with a preset sampling rate; Determining a tire contact ratio according to the contact time and the cycle time; The contact angle of the tire is determined according to the contact ratio and the angle corresponding to the cycle time.

7. A method for testing tire contact patch length as claimed in claim 1, characterized in that: The step of obtaining the geometric radius of the tire and determining the contact patch length of the tire in combination with the contact angle specifically includes: Get the geometric radius of the tire and combine it with the contact angle to determine the contact footprint length of the tire: Among them, C l is the contact patch length of the tire, a is the half-length of the tire contact, R is the geometric radius of the tire, and Δφ is the tire contact angle.

8. A method for testing tire contact patch length as claimed in claim 1, characterized in that: Also includes: According to the geometric radius, combined with the contact angle, the tire sinkage is determined: Among them, l is the tire sinkage, R is the geometric radius of the tire, and Δφ is the tire contact angle.

9. A tire contact patch length testing device, characterized in that: include: Data acquisition module, circumferential strain curve construction module, ground contact angle calculation module, ground contact mark length test module; Wherein, the data acquisition module is used to collect strain waveform data of tire movement; The circumferential strain curve construction module is used to determine the tire circumferential strain curve according to the strain waveform data in combination with a preset flexible carcass model; The contact angle calculation module is used to determine the contact angle of the tire according to the circumferential strain curve in combination with a preset sampling rate; The contact patch length testing module is used to obtain the geometric radius of the tire and determine the contact patch length of the tire in combination with the contact angle.

10. A tire contact patch length testing device as claimed in claim 9, characterized in that: The contact patch length test module comprises: a contact patch length test unit; The contact patch length testing unit is used to obtain the geometric radius of the tire and determine the contact patch length of the tire in combination with the contact angle: Among them, C l is the contact patch length of the tire, a is the half-length of the tire contact, R is the geometric radius of the tire, and Δφ is the tire contact angle.

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