Driving evaluation method, driving evaluation device, and driving evaluation program

Abstract

To provide a driving evaluation method, a driving evaluation device, and a driving evaluation program which can derive advantageous information on improvement of driving skills.SOLUTION: A driving evaluation method includes a tire force acquisition step, a ratio calculation step, and an evaluation value calculation step. The tire force acquisition step acquires tire force during travelling of a vehicle. The ratio calculation step calculates a ratio value by dividing the tire force acquired in the tire force acquisition step by a load value. The evaluation value calculation step calculates an evaluation value by integrating such the tire force that the ratio value acquired in the ratio calculation step is in a range set by a threshold.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a driving evaluation method, a driving evaluation device, and a driving evaluation program for evaluating a driver's vehicle driving skill. [Background technology]

[0002] Patent Document 1 describes a driving characteristic evaluation method for evaluating a driver's driving characteristics. This driving characteristic evaluation method includes a tire force acquisition step of acquiring tire forces acting on the vehicle's tires at predetermined intervals while the vehicle is traveling, and an index derivation step of determining an evaluation index that indicates the driving characteristics of the driver of the vehicle based on statistical variations in the acquired tire forces. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-55349 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when a vehicle is driven on a circuit, it is desirable to evaluate the driving skill using the tire force obtained during driving and to give advice for improving the lap time around the course. In the evaluation of the statistical variation in tire force by the driving characteristic evaluation method described in Patent Document 1, it is not necessarily possible to fully evaluate the degree of tire force generated in a section such as a curve, for example, and it is difficult to give sufficient advice for improving the lap time. The present inventor thought that there is room for improvement in evaluation that can derive information advantageous for improving the driving skill of the vehicle by performing an evaluation that reliably reflects the tire force generated during braking and driving of the vehicle.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a driving evaluation method, a driving evaluation device, and a driving evaluation program that can derive information that is advantageous for improving driving skills. [Means for solving the problem]

[0006] One aspect of the present invention is a driving evaluation method, which includes a tire force acquisition step of acquiring tire forces while a vehicle is traveling, a ratio calculation step of calculating a ratio value by dividing the tire force acquired in the tire force acquisition step by a load value, and an evaluation value calculation step of integrating tire forces that fall within a range determined by a threshold value to calculate an evaluation value.

[0007] Another aspect of the present invention is a driving evaluation device that includes a tire force acquisition unit that acquires tire forces when a vehicle is traveling, a ratio calculation unit that calculates a ratio value by dividing the tire force acquired by the tire force acquisition unit by a load value, and an evaluation value calculation unit that calculates an evaluation value by integrating tire forces that fall within a range determined by a threshold value.

[0008] Another aspect of the present invention is a driving evaluation program that causes a computer to execute a tire force acquisition step of acquiring tire forces while a vehicle is traveling, a ratio calculation step of calculating a ratio value by dividing the tire force acquired in the tire force acquisition step by a load value, and an evaluation value calculation step of integrating tire forces that fall within a range defined by a threshold value to calculate an evaluation value. Effect of the Invention

[0009] According to the present invention, it is possible to derive useful information regarding improvement of driving skills. [Brief description of the drawings]

[0010] [Figure 1]1 is a schematic diagram for explaining an overview of a driving evaluation system including a driving evaluation device according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a functional configuration of the tire force estimation device. [Diagram 3] FIG. 2 is a schematic diagram showing a configuration of a computation model. [Figure 4] FIG. 2 is a block diagram showing a functional configuration of a driving evaluation device. [Diagram 5] This is a chart showing the range of calculations for FR and FF vehicles. [Figure 6] 5 is a flowchart showing a procedure for calculating an evaluation value by a tire force estimation device and a driving evaluation device. [Figure 7] 13 is a graph showing an example of tire force of a front tire. [Figure 8] 13 is a graph showing an example of tire force of a rear tire. [Figure 9] 13 is a graph showing an example of ratio values ​​Rx and Ry of front tires. [Figure 10] 13 is a graph showing examples of ratio values ​​Rx and Ry for rear tires. [Figure 11] 1 is a table showing an example of tire force evaluation values ​​calculated for an FR vehicle and an FF vehicle. [Figure 12] 13 is a graph showing the correlation between evaluation values ​​Eb and Ea and lap times. [Figure 13] 13 is a graph showing the correlation between the overall evaluation value E and lap time. [Figure 14] FIG. 11 is a block diagram showing a functional configuration of a driving evaluation device according to a second embodiment. [Figure 15] 5 is a flowchart showing a procedure for calculating an index value by the tire force estimation device and the driving evaluation device. [Figure 16] 11 is a table showing index values ​​calculated by an index value calculation unit. [Figure 17] 11 is a table showing index values ​​calculated by an index value calculation unit and details of improvement. [Figure 18] FIG. 11 is a block diagram showing a functional configuration of a driving evaluation system including a driving evaluation device according to a third embodiment. [Figure 19] 4 is a graph showing an example of acceleration data acquired while a vehicle is traveling. [Figure 20] 4 is a flowchart showing a procedure for calculating an evaluation value by a driving evaluation device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described below based on preferred embodiments with reference to Figures 1 to 20. The same or equivalent components and members shown in each drawing are given the same reference numerals, and duplicated descriptions will be omitted as appropriate. The dimensions of the members in each drawing are enlarged or reduced as appropriate for ease of understanding. Some of the members that are not important for explaining the embodiments in each drawing are omitted.

[0012] (Embodiment 1) 1 is a schematic diagram for explaining an overview of a driving evaluation system 100 including a driving evaluation device 50 according to embodiment 1. The driving evaluation system 100 includes a sensor 10 disposed in each tire 1 mounted on a vehicle 8, a vehicle measurement device 20, a tire force estimation device 30, and a driving evaluation device 50.

[0013] The sensor 10 measures physical quantities of the tire 1, such as the acceleration and distortion of the tire 1, the tire air pressure, and the tire temperature. The vehicle measurement device 20 accumulates the physical quantities of the tire 1 measured in time series by the sensor 10, and transmits them to the tire force estimation device 30 via a communication network 9. For example, the vehicle 8 is driven on a circuit, and the physical quantities of the tire 1 during the drive are stored in time series by the vehicle measurement device 20, and transmitted to the tire force estimation device 30 after the drive has ended.

[0014] The tire force estimation device 30 estimates tire force based on data measured by the sensor 10 received from the vehicle measurement device 20. The tire force estimation device 30 uses data measured by the sensor 10 in a calculation to estimate tire force, but may also obtain information measured on the vehicle 8 side, such as vehicle acceleration, and use this in a calculation to estimate tire force. The tire force estimation device 30 estimates tire force while the vehicle 8 is traveling, for example, on a circuit.

[0015] The driving evaluation device 50 evaluates the driving skill based on the tire force estimated by the tire force estimation device 30 and provides advice information for improving the driving skill. The driving evaluation device 50 integrates the tire force generated while the vehicle 8 is traveling on a circuit, for example, and evaluates how much tire force was generated to cause the vehicle 8 to travel.

[0016] The number of vehicles 8 is not limited to one, and may be multiple. The driving evaluation device 50 can use many vehicles 8 as comparison subjects by evaluating the tire force generation conditions for many vehicles 8, and can derive more advantageous information for improving driving skills.

[0017] 2 is a block diagram showing the functional configuration of the tire force estimation device 30. The sensor 10 has an acceleration sensor 11, a strain gauge 12, a pressure gauge 13, a temperature sensor 14, etc., and measures physical quantities in the tire 1. These sensors measure physical quantities related to the deformation and movement of the tire 1 as physical quantities of the tire 1. The vehicle measurement device 20 accumulates the physical quantities generated in the tire 1 measured by the sensor 10, and transmits them to the tire force estimation device 30.

[0018] The acceleration sensor 11 and the strain gauge 12 move mechanically together with the tire 1 and measure the acceleration and the amount of strain, respectively, occurring in the tire 1. The acceleration sensor 11 is disposed, for example, in the tread, side, bead, wheel, etc. of the tire 1, and measures the acceleration of the tire 1 in three axes: the circumferential direction, the axial direction, and the radial direction.

[0019] The strain gauges 12 are disposed in the tread, sides, beads, etc. of the tire 1, and measure the strain at the locations where they are disposed. The pressure gauge 13 and temperature sensor 14 are disposed, for example, in an air valve of the tire 1, and measure the tire air pressure and tire temperature, respectively. The temperature sensor 14 may be disposed directly on the tire 1 in order to accurately measure the temperature of the tire 1. The tires 1 may be fitted with, for example, an RFID 1a or the like to which unique identification information is assigned in order to identify each tire.

[0020] The tire force estimation device 30 has a data acquisition unit 31, a tire force estimation unit 32, a storage unit 33, and a communication unit 34. The tire force estimation device 30 is an information processing device such as a PC (personal computer). In terms of hardware, each unit in the tire force estimation device 30 can be realized by an electronic processing circuit made up of electronic elements such as a computer CPU, or mechanical parts, and in terms of software, by a computer program, etc., but here, functional blocks realized by the cooperation of these are depicted. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.

[0021] The data acquisition unit 31 acquires information on acceleration, strain, air pressure, and temperature measured by the sensor 10 from the vehicle measurement device 20 via wireless communication or the like. The communication unit 34 communicates with the driving evaluation device 50 via wired or wireless communication or the like, and transmits tire force data estimated by the tire force estimation unit 32 to the driving evaluation device 50.

[0022] Tire force estimation unit 32 has a calculation model 32a, and inputs information from data acquisition unit 31 to calculation model 32a to estimate tire force F. As shown in Fig. 2, tire force F has three axial components: a longitudinal force Fx in the longitudinal direction of tire 1, a lateral force Fy in the lateral direction, and a load Fz in the vertical direction. Tire force estimation unit 32 may calculate all of these three axial components, or may calculate at least one of the components or two components in any combination.

[0023] The computation model 32a uses a learning model such as a neural network. Fig. 3 is a schematic diagram showing the configuration of the computation model 32a. The computation model 32a is a CNN (Convolutional Neural Network) type, and is a learning model equipped with convolution and pooling operations used in the prototype of the computation model, so-called LeNet. Fig. 3 shows an example in which acceleration data in three axial directions is used as input data to the computation model 32a, and tire forces in three axial directions are output.

[0024] The computational model 32a includes an input layer 40, a feature extraction unit 41, an intermediate layer 42, a full connection unit 43, and an output layer 44. Time series data of acceleration in three axial directions acquired by the data acquisition unit 31 is input to the input layer 40. The acceleration data is measured in time series by the sensor 10, and data within a certain time interval is extracted using a window function to be used as input data.

[0025] The acceleration measured at the tire 1 is periodic for each rotation of the tire 1. The time interval of the input data extracted by the window function may be, for example, a time period corresponding to the rotation period of the tire 1, and the input data itself may be periodic. Note that the window function may extract input data in a time interval shorter or longer than one rotation of the tire 1, and as long as the extracted input data contains at least periodic information, learning of the computation model 32a is possible.

[0026] The feature extraction unit 41 extracts features using a convolution operation, a pooling operation, etc., and transmits them to each node of the intermediate layer 42. The feature extraction unit 41 performs a convolution operation on the input data using a plurality of filters. The convolution operation is performed while moving the filter on the time-series input data such as acceleration data. The pooling operation is performed on the data after the convolution operation by performing a maximum value pooling operation that selects the larger value of two values ​​arranged in a time series, for example. The feature extraction unit 41 repeats the convolution operation, the pooling operation, etc., to extract features.

[0027] The full connection unit 43 fully connects data from each node in the intermediate layer 42 in one or more hierarchical layers, and outputs tire forces Fx, Fy, and Fz to each node in the output layer 44. The full connection unit 43 performs calculations by fully connected paths that execute linear calculations using weighting, etc., but in addition to the linear calculations, it may also be configured to execute nonlinear calculations using activation functions, etc.

[0028] Each node of the output layer 44 may be configured to output information such as the tire forces in the three axial directions as well as the moments about the three axes acting on the tire 1. The tire forces estimated by the computation model 32a are stored in the storage unit 33. The storage unit 33 is a storage device constituted by, for example, an SSD (Solid State Drive), a hard disk, a CD-ROM, a DVD, etc., and stores the tire forces estimated for each tire 1 mounted on the vehicle 8 that has been driven on a circuit, for example.

[0029] The calculation model 32a can learn the calculation model 32a by mounting a tire 1 having specifications corresponding to the vehicle on an actual vehicle and running the vehicle on a test run. The specifications of the tire 1 include information on tire performance, such as tire size, tire width, aspect ratio, tire strength, tire outer diameter, load index, and manufacturing date.

[0030] Fig. 4 is a block diagram showing the functional configuration of the driving evaluation device 50. The driving evaluation device 50 includes a communication unit 51, a tire force acquisition unit 52, and a calculation processing unit 53. The driving evaluation device 50 is an information processing device such as a PC (personal computer). Each unit in the driving evaluation device 50 can be realized in terms of hardware by electronic processing circuits and mechanical parts made up of electronic elements such as a computer CPU, and in terms of software by a computer program, but here, functional blocks realized by cooperation between them are depicted. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.

[0031] The communication unit 51 communicates with the tire force estimation device 30 via wired or wireless communication, etc. The tire force acquisition unit 52 receives and acquires data of the tire forces estimated by the tire force estimation device 30 via the communication unit 51. The tire forces acquired by the tire force acquisition unit 52 are, for example, tire forces in three axial directions estimated for each tire 1 mounted on a vehicle 8 that has traveled on a circuit.

[0032] The calculation processing unit 53 has a ratio calculation unit 53a and an evaluation value calculation unit 53b. The ratio calculation unit 53a divides the longitudinal force Fx and the lateral force Fy, among the tire forces in the three axial directions for each tire 1 on the vehicle 8, by the load Fz to obtain ratio values ​​Rx and Ry.

[0033] The ratio values ​​Rx and Ry obtained by dividing the longitudinal force Fx and the lateral force Fy by the load Fz are values ​​of the same dimension as the friction coefficient value. If the ratio values ​​Rx and Ry are greater than the maximum friction coefficient between the road surface and tire 1, it is basically considered that tire 1 is in a slipping state.

[0034] For example, if the time required for one lap of a vehicle 8 that has traveled around a circuit is 200 seconds and the tire force is estimated every 0.2 seconds, then 1000 pieces of data each of the ratio values ​​Rx and Ry are obtained. If the vehicle 8 is equipped with a total of four tires 1, front and rear, then 4000 pieces of data each of the ratio values ​​Rx and Ry are obtained.

[0035] When the ratio values ​​Rx and Ry are large values ​​close to but not exceeding the maximum coefficient of friction, the vehicle 8 is being driven in a state where tire force is generated to the limit where the tires 1 do not slip. Conversely, when the ratio values ​​Rx and Ry are small values ​​far from the maximum coefficient of friction, the vehicle 8 is being driven in a state where the tires 1 do not slip but where sufficient tire force is not being generated.

[0036] The evaluation value calculation unit 53b calculates the evaluation value E by accumulating the tire forces having ratio values ​​Rx and Ry that fall within a range determined by a predetermined threshold value. The range determined by the predetermined threshold value is basically determined as a range in which the absolute values ​​of the ratio values ​​Rx and Ry are greater than a predetermined threshold value, for example, 0.5. The predetermined threshold value is not limited to 0.5.

[0037] The range determined by the predetermined threshold value is set as a range of 0 or more (or greater than 0) for the ratio value Rx of the longitudinal force Fx, taking into consideration when braking the vehicle 8. The range determined by the predetermined threshold value is set as a range of 0 or less (or smaller than 0) for the ratio value Rx of the longitudinal force Fx, taking into consideration when driving the vehicle 8. In other words, the range determined by the predetermined threshold value is the target range of tire forces when accumulating to calculate the evaluation value.

[0038] The evaluation value calculation unit 53b extracts tire forces based on the weight balance and drive wheel information of the vehicle 8, and sets the tire forces as the target range for accumulating the evaluation values. Fig. 5 is a chart showing the ranges of the calculation targets for FR vehicles and FF vehicles. Here, it is assumed that the weight balance of the vehicle 8 is such that the engine is mounted on the front side of the vehicle, and the center of gravity is located closer to the front than the center of the vehicle 8 in the fore-and-aft direction.

[0039] In the case of an FR vehicle with rear-wheel drive, when braking the vehicle 8, the tire force on the front wheels contributes more to braking the vehicle 8 than the rear wheels, and the tire force on the front tires 1 during braking is integrated to calculate an evaluation value Eb. The evaluation value Eb is an integrated value of tire forces focused on during braking. When driving an FR vehicle, the tire force on the rear wheels contributes more to driving the vehicle 8 than the front wheels, and the tire force on the rear tires 1 during driving is integrated to calculate an evaluation value Ea. The evaluation value Ea is an integrated value of tire forces focused on during driving. The overall evaluation value E is calculated by E=Eb+Ea.

[0040] In the case of a FF vehicle with the driven wheels on the front wheels, the tire force on the front wheels contributes more to braking of the vehicle 8 than the rear wheels, and the tire force during braking is integrated for the front tire 1 to calculate the evaluation value Eb. Also, when a FF vehicle is driving, the tire force on the front wheels contributes more to braking than the rear wheels, and the tire force during driving is integrated for the front tire 1 to calculate the evaluation value Ea.

[0041] When integrating tire forces to calculate an evaluation value, evaluation value calculation unit 53b integrates the magnitude of tire force Fs, which is a vector combination of longitudinal force Fx and lateral force Fy among the tire forces in the three axial directions. For FR vehicles, evaluation value E can be calculated by the following formula. E=Eb+Ea =Σ(Fs when braking the front tires) + Σ(Fs when driving the rear tires) (1)

[0042] Here, Eb=Σ (Fs when braking the front tires) and Ea=Σ (Fs when driving the rear tires).

[0043] For FF vehicles, the evaluation value E can be calculated using the following formula: E=Eb+Ea =Σ(Fs when braking the front tires) + Σ(Fs when driving the front tires) (2)

[0044] Here, Eb=Σ (Fs when braking the front tires), and Ea=Σ (Fs when driving the front tires).

[0045] The driving evaluation device 50 provides the evaluation values ​​E, Eb, and Ea calculated by the evaluation value calculation unit 53b to the user by displaying them on a display device, etc. The driving evaluation device 50 may also simultaneously display lap times, etc., and provide the user with the relationship between the evaluation values ​​E, Eb, and Ea, and the lap times.

[0046] Next, the operation of the driving evaluation device 50 will be described. Fig. 6 is a flowchart showing the procedure for calculating an evaluation value by the tire force estimation device 30 and the driving evaluation device 50. The data acquisition unit 31 of the tire force estimation device 30 acquires data on the physical quantities of the tires 1 measured by the sensors 10 (S1). The tire force estimation unit 32 estimates tire forces in three axial directions using a calculation model 32a (S2). The tire force estimation unit 32 estimates tire forces occurring during driving on a circuit, for example, for each tire 1 mounted on a vehicle that has driven on a circuit.

[0047] Tire force acquisition unit 52 of driving evaluation device 50 acquires data of tire forces estimated by tire force estimation unit 32 of tire force estimation device 30 (S3). Ratio calculation unit 53a calculates ratio values ​​Rx and Ry by dividing the longitudinal force Fx and the lateral force Fy, among the tire forces, by the load Fz (S4).

[0048] The evaluation value calculation unit 53b extracts tire forces that fall within a range determined by a predetermined threshold value (S5). The evaluation value calculation unit 53b integrates the tire forces extracted in step S5 to calculate an evaluation value E (S6), and ends the process. For example, in the case of an FR vehicle, the evaluation value calculation unit 53b calculates an evaluation value Eb during braking by Eb=Σ (Fs when braking the front tires) and an evaluation value Ea during driving by Ea=Σ (Fs when driving the rear tires), and calculates an overall evaluation value E by adding Eb and Ea.

[0049] Fig. 7 is a graph showing an example of tire force of a front tire, and Fig. 8 is a graph showing an example of tire force of a rear tire. In Fig. 7 and Fig. 8, the horizontal axis represents lateral force Fy, the vertical axis represents longitudinal force Fx, and the longitudinal force Fx and lateral force Fy estimated in time series are plotted. The tire forces shown in Fig. 7 and Fig. 8 are estimated for each tire 1 mounted on an FR vehicle that has been driven around a circuit once.

[0050] In the front tires shown in Figure 7, the longitudinal force Fx is mostly generated as a positive value, although some of it is a negative value, which indicates that the positive longitudinal force Fx acts as a braking force. Also, in the front tires shown in Figure 7, the lateral force Fy is distributed between negative and positive values ​​with 0N as the boundary, and the polarity is in line with the curve in both the left and right directions.

[0051] In the rear tires shown in Figure 8, the negative longitudinal force Fx acts as a driving force to accelerate the vehicle, and the positive longitudinal force Fy acts as a braking force. Also, in the rear tires shown in Figure 8, the lateral force Fy is distributed on both sides of 0N, and has a polarity that matches the curve in both the left and right directions.

[0052] Fig. 9 is a graph showing an example of ratio values ​​Rx and Ry of the front tires, and Fig. 10 is a graph showing an example of ratio values ​​Rx and Ry of the rear tires. In Fig. 9 and Fig. 10, the horizontal axis represents the ratio value Ry, the vertical axis represents the ratio value Fx, and the ratio value Rx and lateral force Ry calculated in time series are plotted. The ratio values ​​shown in Fig. 9 and Fig. 10 are estimated for each tire 1 mounted on an FR vehicle that has been driven around a circuit once.

[0053] For the front tires shown in Figure 9, although some of the ratio values ​​Rx are negative, most of them are positive, indicating that the tire force is acting as a braking force. For the rear tires shown in Figure 10, a negative ratio value Rx indicates that the tire force is acting as a driving force. For the rear tires shown in Figure 10, a positive ratio value Rx indicates that the tire force is acting as a braking force.

[0054] The evaluation value calculation unit 53b extracts ratio values ​​Rx and Ry that are within a range determined by a predetermined threshold value from the ratio values ​​Rx and Ry plotted as in Figures 9 and 10. The evaluation value calculation unit 53b extracts tire forces that correspond to the extracted ratio values ​​Rx and Ry.

[0055] The evaluation value calculation unit 53b extracts, for the front tires, a ratio value that is in range A represented as the union of the range in which the ratio value Ry is equal to or less than the first threshold value SF1 = -0.5 or equal to or more than the second threshold value SF2 = +0.5, and the ratio value Rx is equal to or more than the third threshold value SF3 = 0, and the range in which the ratio value Rx is equal to or more than the fourth threshold value SF4 = +0.5.

[0056] 9, the range from which the ratio value is extracted is the range where the ratio value Rx is above the third threshold value SF3 when the ratio value Ry is equal to or less than the first threshold value SF1 or equal to or more than the second threshold value SF2. The range from which the ratio value is extracted is the range where the ratio value Rx is above the fourth threshold value SF4 when the ratio value Ry is greater than the first threshold value SF1 and less than the second threshold value SF2.

[0057] The evaluation value calculation unit 53b calculates an evaluation value Eb=Σ(when braking the front tires Fs) for an FR vehicle by extracting and integrating tire forces corresponding to the ratio values ​​Rx and Ry extracted for the front tires.

[0058] The evaluation value calculation unit 53b extracts, for the rear tires, a ratio value that is in range B represented as the union of the range in which the ratio value Ry is equal to or less than the first threshold value SR1 = -0.5 or equal to or more than the second threshold value SR2 = +0.5, and the range in which the ratio value Rx is equal to or less than the third threshold value SR3 = 0, and the range in which the ratio value Rx is equal to or less than the fourth threshold value SR4 = -0.5.

[0059] 10, the range from which the ratio value is extracted is a range in which the ratio value Rx is below the third threshold SR3 when the ratio value Ry is equal to or less than the first threshold SR1 or equal to or greater than the second threshold SR2. The range from which the ratio value is extracted is a range in which the ratio value Rx is below the fourth threshold SR4 when the ratio value Ry is greater than the first threshold SR1 and less than the second threshold SR2.

[0060] The evaluation value calculation unit 53b calculates an evaluation value Ea=Σ(rear tires when driven Fs) for an FR vehicle by extracting and integrating tire forces corresponding to the ratio values ​​Rx and Ry extracted for the rear tires.

[0061] The case of a FF vehicle will be described. The evaluation value calculation unit 53b calculates the evaluation value Eb during braking based on the tire force generated in the front tires. As in the case of an FR vehicle, the evaluation value calculation unit 53b calculates the evaluation value Eb by integrating the tire force Fs of the front tires where the comparison values ​​Rx and Ry belong to the range A defined by the first threshold value SF1, the second threshold value SF2, the third threshold value SF3, and the fourth threshold value SF4.

[0062] In the case of a FF vehicle, the evaluation value calculation unit 53b calculates the evaluation value Ea during driving based on the tire force generated in the front tires. The evaluation value calculation unit 53b calculates the evaluation value Ea by integrating the tire force Fs of the front tires where the comparison values ​​Rx and Ry belong to the range B defined by the first threshold value SR1, the second threshold value SR2, the third threshold value SR3, and the fourth threshold value SR4.

[0063] Fig. 11 is a chart showing an example of tire force evaluation values ​​calculated for FR vehicles and FF vehicles. Fig. 11 shows the evaluation values ​​and lap times for three FR vehicles and three FF vehicles. Vehicle FR-1, which has the shortest lap time among the FR vehicles, has the largest evaluation value Eb during braking, the largest evaluation value Ea during driving, and the largest overall evaluation value E.

[0064] Fig. 12 is a graph showing the correlation between the evaluation values ​​Eb and Ea and the lap time, and Fig. 13 is a graph showing the correlation between the overall evaluation value E and the lap time. As shown in Fig. 12, the shorter the lap time, the larger the evaluation value Eb during braking and the evaluation value Ea during driving, which indicates that driving operations are performed in such a way that larger tire forces are generated during braking and driving. The longer the lap time, the smaller the evaluation value Eb during braking and the evaluation value Ea during driving, which indicates that driving operations are performed in a state in which sufficient tire forces are not generated during braking and driving. The driving operations include steering, braking, accelerating, etc., performed by the driver.

[0065] As shown in Fig. 13, the shorter the lap time, the larger the overall evaluation value E, indicating that the driving operation is performed in a manner that generates a larger tire force. The longer the lap time, the smaller the overall evaluation value E, indicating that the driving operation is performed in a state in which sufficient tire force is not being generated during braking and driving.

[0066] The driving evaluation device 50 uses the evaluation value calculation unit 53b to calculate the evaluation values ​​Ea, Eb, and E from the tire forces where the comparison values ​​Rx and Ry fall within a range determined by a predetermined threshold value. For example, the lap time of a vehicle traveling around a circuit can be shortened by maximizing the use of tire forces during braking and driving. The evaluation value calculation unit 53b calculates an evaluation value by integrating the tire forces when the ratio values ​​Rx and Ry are equal to or greater than a certain value determined by the threshold value, thereby reflecting the tire forces and deriving information that is useful for improving driving skills.

[0067] Evaluation value calculation unit 53b of driving evaluation device 50 calculates evaluation value Eb during braking and evaluation value Ea during driving using tire forces extracted based on at least one of information on the vehicle weight balance and driving wheels. This enables driving evaluation device 50 to extract tire forces that have a large influence on the braking and driving (acceleration) of the vehicle, and derive more accurate information that leads to improvement of driving skills.

[0068] When the vehicle is a rear-wheel drive FR vehicle, the evaluation value calculation unit 53b calculates an evaluation value by integrating the tire force of the front tires during braking and the tire force of the rear tires during driving. This enables the driving evaluation device 50 to extract tire forces that have a high influence according to the drive wheels, and derive more accurate information that leads to improvement of driving skills.

[0069] Furthermore, when the vehicle is a front-wheel drive FF vehicle, the evaluation value calculation unit 53b calculates an evaluation value by integrating the tire force of the front tires during braking and the tire force of the front tires during driving. This enables the driving evaluation device 50 to extract tire forces that have a high influence according to the drive wheels, and derive more accurate information that leads to the improvement of driving skills.

[0070] The evaluation value calculation unit 53b calculates ratio values ​​Rx and Ry by dividing the longitudinal force Fx and the lateral force Fy by the load Fz, and extracts tire forces that fall within a range determined by a predetermined threshold value for the ratio values ​​Rx and Ry. This enables the driving evaluation device 50 to distinguish between braking and driving from the longitudinal ratio value Rx, and to extract tire forces that have a high degree of influence on vehicle travel from ratio values ​​Rx and Ry that are equal to or greater than a certain level.

[0071] In the above example, the weight balance of the vehicle is closer to the front than the center in the front-rear direction of the vehicle. When the weight balance is closer to the rear of the vehicle, the evaluation value calculation unit 53b calculates the evaluation value including the braking force of the rear tires, and it is considered that the evaluation value calculation unit 53b can derive advantageous information that leads to improvement of driving skills.

[0072] In the case of a four-wheel drive vehicle, the evaluation value calculation unit 53b may extract the tire forces of both the front and rear tires to calculate the evaluation value during driving. Also, when the tire force of either the front or rear tires contributes significantly to the driving of the vehicle in relation to the weight balance, the evaluation value calculation unit 53b may calculate the evaluation value using the tire force of that one tire.

[0073] (Embodiment 2) 14 is a block diagram showing a functional configuration of a driving evaluation device 50 according to embodiment 2. The driving evaluation device 50 according to embodiment 2 has an index value calculation unit 53c and an improvement determination unit 54 in addition to the components of the driving evaluation device 50 according to embodiment 1.

[0074] The index value calculation unit 53c calculates the index value I from the evaluation value calculated by the evaluation value calculation unit 53b based on a predetermined reference value. The index value calculation unit 53c may use, for example, an already acquired evaluation value E as the predetermined reference value. The index value calculation unit 53c may use, for example, the evaluation value E of one vehicle among the evaluation values ​​E acquired for a plurality of vehicles as a reference value, and may set the ratio obtained by dividing the evaluation values ​​E of the other vehicles by the reference value as the index value I.

[0075] In addition, the index value calculation unit 53c may, for example, use any one of the evaluation values ​​E obtained multiple times for a vehicle as a reference value, and use the ratio obtained by dividing the other evaluation values ​​E by the reference value as the index value I.

[0076] The index value calculation unit 53c may set the index value I of the evaluation value E adopted as the reference value to 100%. The index value calculation unit 53c may also calculate the index value I by multiplying the value obtained by dividing the evaluation value by the reference value by an attenuation amount such as 0.8. In this case, the index value calculation unit 53c calculates the index value I of the evaluation value E adopted as the reference value to be, for example, 80%, taking into account the attenuation amount.

[0077] The index value calculation unit 53c may calculate an index value Ib during braking and an index value Ia during driving based on predetermined reference values ​​for the evaluation value Eb during braking and the evaluation value Ea during driving, respectively.

[0078] The improvement determination unit 54 determines the improvement of the driving skill based on the index values ​​Ib, Ia, and I calculated by the index value calculation unit 53c. The improvement is for the braking operation and the accelerator operation in relation to the driving skill, and for the tires, for the tire performance (e.g., rubber stiffness, grip performance, etc.).

[0079] The improvement determination unit 54 may rank the index values ​​Ib, Ia, and I calculated by the index value calculation unit 53c into multiple stages and set the improvement content for each rank in advance. The improvement determination unit 54 may determine which rank the index values ​​Ib, Ia, and I calculated by the index value calculation unit 53c belong to, and present the improvement content set for the determined rank.

[0080] Next, the operation of the driving evaluation device 50 will be described. Figure 15 is a flowchart showing the procedure for calculating index values ​​by the tire force estimation device 30 and the driving evaluation device 50. The processing from steps S11 to S16 in Figure 15 is equivalent to the processing from steps S1 to S6 shown in Figure 6, and therefore the description will be omitted for brevity.

[0081] The index value calculation unit 53c calculates an index value I from the evaluation value calculated in step S16 based on a predetermined reference value (S17). The index value calculation unit 53c uses, for example, an already acquired evaluation value E as the predetermined reference value. The improvement determination unit 54 determines the improvement content of the driving skill based on the index values ​​Ib, Ia, and I calculated in step S17 (S18), and ends the process.

[0082] Fig. 16 is a chart showing index values ​​calculated by the index value calculation unit 53c. The index value calculation unit 53c sets the overall evaluation value E of the vehicle FR-1 with the shortest lap time as a reference value, divides each evaluation value E by the reference value, and multiplies it by an attenuation amount of 0.8 to calculate an overall index value I (percentage). As shown in Fig. 16, compared to the vehicle FR-1 with the short lap time (index value is 80), the index value I of other vehicles FR-2, etc. is small, and it can be seen that there are areas for improvement in the operation of the brake, accelerator, etc.

[0083] By calculating the index value I in the index value calculation unit 53c, the driving evaluation device 50 can derive information that reflects the tire force and is useful for improving the driving skill, making it easier to recognize that the driving skill needs to be improved.

[0084] 17 is a table showing the index values ​​calculated by the index value calculation unit 53c and the details of improvement. In addition to the overall index value I, FIG. 17 shows the index value Ib during braking and the index value Ia during driving.

[0085] The index value Ib during braking and the index value Ia during driving may use the overall evaluation values ​​Eb and Ea of the vehicle FR-1, which has the shortest lap time, as the reference value, or the evaluation values ​​of the other vehicles as the reference value. In the example shown in Fig. 17, the index value calculation unit 53c calculates the index value Ib during braking and the index value Ia during driving of each vehicle by using the evaluation value Eb of the vehicle FR-3 as the reference value (no attenuation).

[0086] The driving evaluation device 50 can provide information relating to the evaluation of tire forces during braking and accelerating operations in an easier-to-recognize manner by calculating the index values ​​Ib and Ia in the index value calculation section 53c.

[0087] As shown in Fig. 17, the improvement determination unit 54 ranks the index values ​​Ib and Ia and determines the improvement content regarding the driving skill. For example, the improvement determination unit 54 determines that the vehicle FR-1 having high ranks for the index values ​​Ib and Ia has "good brake and accelerator operation". The determination result here may be expressed as "good tire use" for the vehicle FR-1.

[0088] The improvement determination unit 54 determines that "both braking and accelerator operation need improvement" for vehicle FF-1, which has low ranks for index values ​​Ib and Ia. The determination result here may be expressed as "the tires should be used more when braking and accelerating" for vehicle FF-1. In this way, the driving evaluation device 50 can provide information on the improvement content related to driving skill in an easily recognizable format based on the index value calculated by the index value calculation unit 53c.

[0089] 17, the improvement content provided by the improvement determination unit 54 may also include content related to tires. For vehicle FR-2, which has a high index value Ib during braking and a slightly low index value Ia during driving, the improvement determination unit 54 adds, as an improvement content, "tires with high rigidity in the longitudinal direction are recommended." For vehicle FF-1, which has a low index value Ib during braking and a low index value Ia during driving, the improvement determination unit 54 adds, as an improvement content, "high-grip tires are recommended."

[0090] (Modification) In the above-described first and second embodiments, the tire force estimation device 30 and the driving evaluation device 50 are configured separately, but they may be integrated into the driving evaluation device 50 and configured as a single device. In this case, the driving evaluation device 50 is configured to include each of the components of the tire force estimation device 30.

[0091] The tire force is not limited to the method of estimation using a learning-type calculation model as in the above-mentioned tire force estimation device 30, but may be estimated using, for example, a mechanical motion model of the vehicle.

[0092] In the second embodiment, the improvement is not limited to expressions such as "good brake and accelerator operation", but may be an expression that means performing operations related to the brake and accelerator that further increase tire force.

[0093] (Embodiment 3) 18 is a block diagram showing a functional configuration of a driving evaluation system 100 including a driving evaluation device 50 according to embodiment 3. The driving evaluation system 100 according to embodiment 3 measures acceleration generated in a vehicle using a vehicle measurement device 20 and transmits the measured acceleration to the driving evaluation device 50. The acceleration generated in the vehicle is measured by, for example, an acceleration sensor or a gyro sensor fixed to the body of the vehicle.

[0094] Fig. 19 is a graph showing an example of acceleration data acquired while the vehicle is traveling. In Fig. 19, the horizontal axis represents the lateral acceleration of the vehicle, and the vertical axis represents the longitudinal acceleration of the vehicle, and the acceleration data is plotted.

[0095] The driving evaluation device 50 includes a communication unit 55, a vehicle information acquisition unit 56, and a calculation processing unit 57. The driving evaluation device 50 is an information processing device such as a PC (personal computer). Each unit in the driving evaluation device 50 can be realized in terms of hardware by electronic processing circuits and mechanical parts made up of electronic elements such as a computer CPU, and in terms of software by a computer program, but here, functional blocks realized by cooperation between them are depicted. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.

[0096] The communication unit 55 is connected to the communication network 9 by wired or wireless communication or the like, and communicates with the vehicle measuring device 20. The vehicle information acquisition unit 56 acquires acceleration data generated in the vehicle 8 from the vehicle measuring device 20 via the communication unit 55.

[0097] The calculation processing unit 57 includes a data extraction unit 57a and an evaluation value calculation unit 57b. The data extraction unit 57a separates the acceleration data acquired by the vehicle information acquisition unit 56 into deceleration side data and acceleration side data. The data extraction unit 57a extracts acceleration data that belongs to a range determined by a predetermined threshold value from the deceleration side data and the acceleration side data.

[0098] The data extraction unit 57a extracts acceleration data from the deceleration data and the acceleration data in a range in which the absolute value of the acceleration in the longitudinal direction of the vehicle is greater than a predetermined threshold value.

[0099] The evaluation value calculation unit 57b integrates the acceleration data extracted by the data extraction unit 57a to calculate an evaluation value E. For the deceleration side data, the evaluation value calculation unit 57b integrates the acceleration data extracted by the data extraction unit 57a (the magnitude of the combined acceleration vector in the horizontal direction) to calculate an evaluation value Eb.

[0100] The evaluation value calculation unit 57b integrates the acceleration data (the magnitude of the horizontal acceleration vector) extracted by the data extraction unit 57a for the acceleration side data to calculate an evaluation value Ea. The evaluation value calculation unit 57b adds the evaluation values ​​Eb and Eb to calculate an overall evaluation value E.

[0101] Next, the operation of the driving evaluation device 50 will be described. Fig. 20 is a flowchart showing the procedure for calculating an evaluation value by the driving evaluation device 50. The vehicle information acquisition unit 56 of the driving evaluation device 50 acquires acceleration data generated in the vehicle 8 from the vehicle measurement device 20 via the communication unit 55 (S21). The data extraction unit 57a separates the acceleration data into data on the deceleration side and data on the acceleration side (S22).

[0102] The data extraction unit 57a extracts acceleration data that belongs to a range determined by a predetermined threshold value from the deceleration data and the acceleration data (S23). At this time, the data extraction unit 57a extracts acceleration data in a range in which the absolute value of the acceleration in the front-rear direction of the vehicle is greater than the predetermined threshold value, for example.

[0103] The evaluation value calculation unit 57b integrates the acceleration data extracted in step S23 to calculate evaluation values ​​Eb, Ea, and E (S24), and ends the process. The overall evaluation value E is calculated by adding the deceleration side evaluation value Eb and the acceleration side evaluation value Ea.

[0104] The evaluation value calculation unit 57b extracts acceleration data that falls within a range determined by a predetermined threshold value, and accumulates the extracted acceleration data to calculate the evaluation values ​​Eb, Ea, and E. The evaluation values ​​Eb and Ea reflect whether deceleration and acceleration are sufficient, for example, by the driving operation when the vehicle is traveling on a circuit, etc. For example, if the accelerator operation is not sufficient when the vehicle is traveling, the evaluation value Ea becomes small, and if acceleration is maximum, the evaluation value Ea becomes large.

[0105] In addition, the overall evaluation value E, which is the sum of the evaluation value Eb during deceleration and the evaluation value Ea during acceleration, is expected to be large when the driving skill is high and the lap time around the circuit is short, and to be small when the driving skill is low and the lap time around the circuit is long.

[0106] The driving evaluation device 50 can derive advantageous information that leads to improvement of driving skills by extracting and accumulating acceleration data that falls within a range determined by a predetermined threshold value to calculate an evaluation value. In addition, the driving evaluation device 50 can perform more detailed evaluations in each of the situations during deceleration and acceleration, as well as a comprehensive evaluation, by calculating the evaluation values ​​Eb, Ea, and E.

[0107] (Modification) In the above-mentioned embodiments 1 to 3, the vehicle is mainly driven around a circuit or the like, but the driving evaluation system 100 can also be used for driving around a circuit such as a test course, or for driving on a course going from one point to another.

[0108] Furthermore, the driving evaluation system 100 shown in the first to third embodiments may calculate the evaluation value and index value for the entire course on which the vehicle is travelling, or for each section divided by boundaries such as curves and straight lines.

[0109] Next, features of the driving evaluation method, the driving evaluation device 50, and the driving evaluation program according to the embodiment will be described. The driving evaluation method according to the embodiment includes a tire force acquisition step, a ratio calculation step, and an evaluation value calculation step. The tire force acquisition step acquires tire forces when the vehicle 8 is traveling. The ratio calculation step calculates a ratio value by dividing the tire force acquired in the tire force acquisition step by the load value. The evaluation value calculation step calculates an evaluation value by integrating tire forces that fall within a range determined by a threshold value for the ratio value acquired in the ratio calculation step. This driving evaluation method makes it possible to derive information that reflects tire forces and is advantageous for improving driving skills.

[0110] Moreover, the evaluation value calculation step calculates the evaluation value by integrating the tire forces extracted based on at least one of information on the weight balance and the driving wheels of the vehicle 8. According to this driving evaluation method, it is possible to extract tire forces that have a large influence on the braking and driving of the vehicle.

[0111] In addition, in the evaluation value calculation step, when the vehicle 8 is rear-wheel drive, the tire force of the front tires during braking and the tire force of the rear tires during driving are integrated to calculate the evaluation value. According to this driving evaluation method, it is possible to extract tire forces that have a high influence depending on the drive wheels.

[0112] In addition, in the evaluation value calculation step, when the vehicle 8 is front-wheel drive, the tire force of the front tires during braking and the tire force of the front tires during driving are integrated to calculate the evaluation value. According to this driving evaluation method, it is possible to extract tire forces with a high degree of influence according to the drive wheels.

[0113] In the ratio calculation step, the tire forces in the longitudinal and lateral directions are divided by the load value to calculate ratio values. According to this driving evaluation method, it is possible to distinguish between braking and driving from the longitudinal ratio value Rx, and it is possible to extract tire forces that have a high degree of influence on vehicle running from ratio values ​​Rx and Ry that are equal to or greater than a certain level.

[0114] The driving evaluation device 50 includes a tire force acquisition unit 52, a ratio calculation unit 53a, and an evaluation value calculation unit 53b. The tire force acquisition unit 52 acquires tire forces when the vehicle 8 is traveling. The ratio calculation unit 53a calculates a ratio value by dividing the tire force acquired by the tire force acquisition unit 52 by the load value. The evaluation value calculation unit 53b calculates an evaluation value by integrating the tire forces that fall within a range determined by a threshold value for the ratio value acquired by the ratio calculation unit 53a. This enables the driving evaluation device 50 to derive information that reflects the tire forces and is advantageous for improving driving skills.

[0115] The driving evaluation program causes the computer to execute a tire force acquisition step, a ratio calculation step, and an evaluation value calculation step. The tire force acquisition step acquires the tire force when the vehicle 8 is traveling. The ratio calculation step calculates a ratio value by dividing the tire force acquired in the tire force acquisition step by the load value. The evaluation value calculation step calculates an evaluation value by integrating the tire forces that fall within a range determined by a threshold value for the ratio value acquired in the ratio calculation step. This driving evaluation program makes it possible to derive information that reflects the tire forces and is useful for improving driving skills.

[0116] The driving evaluation method includes a vehicle information acquisition step, a data extraction step, and an evaluation value calculation step. The vehicle information acquisition step acquires information measured by the vehicle including acceleration data of the vehicle 8. The data extraction step extracts acceleration data that belongs to a range determined by a predetermined threshold value from the acceleration data acquired in the vehicle information acquisition step. The evaluation value calculation step calculates an evaluation value by integrating the acceleration data extracted in the data extraction step. According to this driving evaluation method, it is possible to derive information that is useful for improving driving skills.

[0117] The above description is based on the embodiments of the present invention. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. Therefore, the descriptions and drawings in this specification should be treated as illustrative rather than restrictive. [Explanation of symbols]

[0118] 8 vehicle, 50 driving evaluation device, 52 tire force acquisition unit, 53a ratio calculation unit; 53b evaluation value calculation unit.

Claims

1. a tire force acquisition step of acquiring tire forces while the vehicle is traveling; a ratio calculation step of calculating a ratio value by dividing the tire force acquired in the tire force acquisition step by a load value; an evaluation value calculation step of integrating tire forces in which the ratio value acquired in the ratio calculation step falls within a range determined by a threshold value to calculate an evaluation value; A driving evaluation method comprising:

2. 2. The driving evaluation method according to claim 1, wherein the evaluation value calculation step calculates the evaluation value by integrating tire forces extracted based on at least one of information on a weight balance and a driving wheel of the vehicle.

3. 2. The driving evaluation method according to claim 1, wherein the evaluation value calculation step calculates the evaluation value by integrating tire forces of front tires during braking and tire forces of rear tires during driving when the vehicle is rear-wheel drive.

4. 2. The driving evaluation method according to claim 1, wherein the evaluation value calculation step calculates the evaluation value by integrating tire forces on front tires during braking and tire forces on front tires during driving when the vehicle is front-wheel drive.

5. 5. The driving evaluation method according to claim 1, wherein the ratio calculation step calculates the ratio value by dividing the tire forces in the longitudinal direction and the lateral direction by the load value.

6. a tire force acquisition unit that acquires tire forces while the vehicle is traveling; a ratio calculation unit that calculates a ratio value by dividing the tire force acquired by the tire force acquisition unit by a load value; an evaluation value calculation unit that calculates an evaluation value by integrating tire forces in which the ratio value acquired by the ratio calculation unit falls within a range determined by a threshold value; A driving evaluation device comprising:

7. a tire force acquisition step of acquiring tire forces while the vehicle is traveling; a ratio calculation step of calculating a ratio value by dividing the tire force acquired in the tire force acquisition step by a load value; an evaluation value calculation step of integrating tire forces in which the ratio value acquired in the ratio calculation step falls within a range determined by a threshold value to calculate an evaluation value; A driving evaluation program that causes a computer to execute the above.

8. a vehicle information acquiring step of acquiring information measured by the vehicle including acceleration data of the vehicle; a data extraction step of extracting acceleration data belonging to a range defined by a predetermined threshold value from the acceleration data acquired in the vehicle information acquisition step; an evaluation value calculation step of integrating the acceleration data extracted in the data extraction step to calculate an evaluation value; A driving evaluation method comprising:

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