JP2010025618A - Vehicle deflection properties testing device, program, and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate a shift amount for precisely evaluating a vehicle deflection properties by a simple method. <P>SOLUTION: Positional information indicating the current position of a vehicle is obtained from a received GPS signal, a travel trajectory is obtained by plotting the positional information upon the travel for a prescribed period of time in a non-steering travel state, an approximate straight-line of the obtained travel trajectory is estimated as the straight travel trajectory when the vehicle travels straight, so as to calculate the amount of shift from the straight travel trajectory upon the travel by a prescribed distance in the non-steering travel state with the measurement start position defined at the time point when the prescribed time has passed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle deflection test apparatus, a program, and a method, and more particularly, to a vehicle deflection test apparatus, a program, and a method for checking vehicle deflection when a vehicle is driven without steering.

  Conventionally, in order to evaluate the straight running stability of a vehicle or a tire, the amount of lateral displacement in a non-steering traveling state in which the vehicle travels without steering has been evaluated. Specifically, when traveling along a predetermined straight reference line, markings are provided at intervals of 50 cm from the measurement start position to the measurement point (100 m, 200 m) so as to be perpendicular to the straight reference line, and the vehicle is not steered. The amount of deviation is measured by entering the measurement start position of the straight reference line in the running state and visually checking the passing positions at the positions of 100 m and 200 m based on the marking.

In addition, in order to suppress a vehicle flow that causes a lateral shift amount in a straight traveling state, it is determined whether or not the vehicle is in a straight traveling state based on a steering angle, a yaw rate, and the like. Based on the vehicle position information, the target travel position is calculated when the vehicle travels a predetermined distance without causing a lateral shift, and the amount of deviation between the actual position traveled for the predetermined distance and the target travel position is greater than or equal to a predetermined value. A vehicle control device that performs steering control has been proposed (for example, Patent Document 1).
JP 2006-31421 A

  However, the conventional method has a problem that the number of steps is increased because it is necessary to provide markings at the measurement positions. In addition, there is a problem that the amount of displacement cannot be measured with high accuracy if it is shifted laterally or obliquely with respect to the straight reference line when entering the measurement start position.

  In addition, the vehicle control device described in Patent Document 1 aims to suppress the vehicle flow during actual travel, and calculates the amount of deviation by complexly judging road information such as road curvature and information such as steering angle. Therefore, there is a problem that evaluation of the deviation amount as a characteristic of the vehicle or the tire itself is not considered.

  The present invention has been made to solve the above problems, and provides a vehicle deflection test apparatus, program, and method capable of calculating a deviation amount for accurately evaluating vehicle deflection by a simple method. The purpose is to provide.

  In order to achieve the above object, a vehicle deflection test apparatus according to the present invention is configured to acquire position information indicating a current position of a vehicle, and to steer the vehicle based on position information acquired by the acquisition means. An estimation means for obtaining a travel locus when the vehicle travels for a predetermined time in a non-steering travel state in which the vehicle travels at a time, and estimating the straight travel locus when the vehicle travels straight based on the determined travel locus; and the elapse of the predetermined time And calculating means for calculating a deviation amount from the straight traveling locus when the vehicle is traveled a predetermined distance in a non-steering traveling state later.

  The vehicle deflection test program according to the present invention causes a computer to travel without steering based on acquisition means for acquiring position information indicating a current position of the vehicle and position information acquired by the acquisition means. An estimation unit that obtains a traveling locus when the vehicle travels for a predetermined time in a non-steering traveling state, and estimates a straight traveling locus when the vehicle travels straight based on the obtained traveling locus; and the vehicle after the predetermined time has elapsed. Is a program for functioning as a calculation means for calculating a deviation amount from the straight traveling locus when traveling for a predetermined distance in a non-steering traveling state.

  According to the vehicle deflection test apparatus and the program of the present invention, the acquisition unit acquires the position information indicating the current position of the vehicle, and the estimation unit does not steer the vehicle based on the position information acquired by the acquisition unit. A travel locus when the vehicle travels for a predetermined time in a non-steered travel state is determined, and a straight travel locus when the vehicle travels straight is estimated based on the obtained travel locus. The calculation means calculates the amount of deviation from the straight travel locus when the vehicle travels a predetermined distance in a non-steering travel state after the predetermined time has elapsed, with the passage of a predetermined time for estimating the straight travel locus as the measurement start time.

  As described above, since the position information acquired by the acquisition unit is used, the shift amount can be calculated more easily than when the passing position is visually checked based on the marking. In addition, a straight traveling locus is estimated from a traveling locus for a predetermined time in a non-steering traveling state, and this straight traveling locus becomes a straight traveling reference line as a reference for measuring a deviation amount. Since there is no horizontal shift or skew with respect to the line, the shift amount can be calculated with high accuracy.

  The acquisition unit may acquire the position information based on a GPS satellite signal. By acquiring the position information based on the GPS satellite signal, the amount of deviation can be calculated easily.

  Further, the calculating means can calculate the amount of deviation when the predetermined distance is traveled by integrating the amount of deviation per unit time. Thus, by accumulating the amount of deviation per unit time, an actual travel locus can be acquired and the vehicle deflection can be evaluated flexibly.

  Further, the predetermined time can be set in a range of 0.3 second to 2 seconds. The travel distance when the vehicle travels at a speed of about 50 km / h for 0.3 seconds corresponds to the distance of one vehicle, so the lower limit of the travel distance necessary to estimate the straight track by 0.3 seconds Value. Similarly, if the vehicle travels at a speed of about 50 km / h for 2 seconds or more, the influence of the vehicle flow due to the non-steering traveling state is included, and an appropriate straight traveling locus cannot be estimated, so the upper limit is 2 seconds. It is.

  Further, the unit time can be in the range of 0.01 seconds to 0.07 seconds. 0.01 seconds is a lower limit value corresponding to the clock frequency of a general measuring instrument, and 0.07 seconds is a time for one rotation of the tire when the vehicle is driven at a speed of about 100 km / h. Is the upper limit.

  The vehicle deflection test method of the present invention includes a step of acquiring position information indicating a current position of the vehicle, and a non-steering traveling state in which the vehicle travels without steering based on the acquired position information for a predetermined time. Obtaining a travel locus when the vehicle travels, estimating a rectilinear trajectory when the vehicle travels straight based on the obtained travel trajectory, and a predetermined distance in a non-steering travel state after the predetermined time has elapsed. And calculating a deviation amount from the straight traveling locus when the vehicle travels.

  In addition, it is possible to calculate the deviation amount for each tire by setting the wheel alignment of the vehicle constant, mounting different types of tires on the vehicle, and executing the above steps for each of the tires.

  As described above, according to the present invention, there is an effect that it is possible to calculate a deviation amount for accurately evaluating the vehicle deflection by a simple method.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, a vehicle deflection test apparatus 10 according to the present embodiment outputs a test result composed of a GPS (Global Positioning System) apparatus 12 for detecting the current position of a vehicle, display means, and the like. And a computer 16 that executes a vehicle deflection test process by calculating an amount of deviation from the straight track of the vehicle.

  The GPS device 12 receives a GPS signal including position information indicating the current position of the vehicle represented by latitude and longitude from a GPS satellite via an antenna installed on the roof of the vehicle.

  The computer 16 includes a CPU 24 that controls the entire vehicle deflection test apparatus 10, a ROM 26 that stores various programs such as a vehicle deflection test program described later, a RAM 28 that temporarily stores data as a work area, and various types of information stored therein. The memory 30 as a storage means, an I / O (input / output) port 32, and a bus connecting them are configured. The GPS device 12 and the output device 14 are connected to the I / O port 32.

  Next, with reference to FIG. 2, the processing routine of the vehicle deflection test program in the present embodiment will be described. This routine starts when the power is turned on by the operator, for example, when the vehicle is in a non-steering traveling state and reaches a predetermined speed for the test.

  In step 100, position information indicating the current position of the vehicle is acquired from the GPS device 12. The position information is sequentially acquired at predetermined unit time intervals (for example, 0.01 seconds to 0.07 seconds). Here, the unit time t is set to 0.05 seconds.

  Next, in step 102, it is determined whether or not a predetermined time ΔT1 has elapsed since the start of acquisition of position information. This predetermined time ΔT1 is a time sufficient for estimating the straight-ahead trajectory in the process of step 106 described later (for example, 0.3 seconds or more), and a short time that does not affect the vehicle flow (for example, 2 seconds or less). Here, ΔT1 is 1 second. If ΔT1 has elapsed, the process proceeds to step 104. If not, the determination in this step is repeated until it has elapsed.

  In step 104, the time when ΔT1 has elapsed is set as the measurement start position at measurement time t = 0. As shown in FIG. 3, the position information is plotted in coordinates with the horizontal axis representing latitude and the vertical axis representing longitude. Here, since the unit time is 0.05 seconds and the predetermined time ΔT1 is 1 second, the position information acquired during ΔT1 is 20, and the position indicated by the 20th position information is measured. Position.

  Next, in step 106, based on the position information acquired during ΔT1, a straight traveling locus is estimated when the vehicle travels straight without causing a vehicle flow. The position information plotted during ΔT1 shown in FIG. 3 is the actual travel locus. Based on this travel locus, for example, an approximate straight line is calculated by a method such as the least square method, and this straight line is used as the straight travel locus 40. presume

  Next, in step 108, vehicle position information is acquired for each unit time, and a deviation amount d from the straight track 40 per unit time is calculated. For example, assuming that the straight locus 40 estimated in step 106 is the y axis, and a line passing through the measurement start position and orthogonal to the y axis is the x axis, the position information at t = t is plotted on the xy coordinates. Is the amount of deviation d1 per unit time.

  Next, in step 110, it is determined whether or not the vehicle has traveled a predetermined distance l for evaluating the deviation amount D. This determination is based on whether or not the time required to travel the predetermined distance l has elapsed since the travel distance is determined by speed × time, assuming that the vehicle speed is a predetermined speed. To do. Since the position information is acquired every unit time t, the elapsed time can be obtained by the number of acquisition times x unit time t. Note that the travel distance may be obtained using a speed actually detected by providing a vehicle speed sensor or the like, or using a travel distance meter. If the vehicle has traveled the predetermined distance l, the process proceeds to step 112.

  If the vehicle has not traveled the predetermined distance l, the process returns to step 108, and based on the position information at t = 2t, the displacement in the x-axis direction from the position at t = t is obtained. The amount of deviation d2 is calculated. Thereafter, until it is determined in step 110 that the vehicle has traveled the predetermined distance l, the process of this step is repeated to calculate d3, d4,.

  When the vehicle has traveled the predetermined distance l, in step 112, the deviation amounts d1 to dn per unit time are integrated to calculate the deviation amount D at the predetermined distance l, and the calculation result is output to the output device 14, The process ends.

  Thus, according to the vehicle deflection testing apparatus in the present embodiment, the position information indicating the current position of the vehicle is acquired by the GPS signal, and the straight traveling locus is estimated from the actual traveling locus obtained using this position information. Since the amount of deviation from the straight track is calculated based on the position information, the amount of deviation can be calculated by a simpler method compared to the case where the amount of deviation is visually measured based on the marking, and the measurement is started. Since there is no lateral shift or skew when entering the position, the shift amount can be calculated with high accuracy.

  Further, the vehicle deflection test processing routine in the present embodiment is executed for each of the tires with the vehicle wheel alignment being fixed, with different types of tires mounted on the vehicle, and thus the deviation amount for each tire is reduced. Can be calculated.

  In the present embodiment, the amount of deviation is calculated every unit time, and the amount of deviation at a predetermined distance is calculated by integrating the predetermined distance travel, but the measurement start position and the position at the time of predetermined distance travel The amount of deviation at a predetermined distance may be calculated directly from the relationship.

It is the schematic which shows the structure of the vehicle deflection test apparatus 10 which concerns on this Embodiment. It is a flowchart which shows the processing routine of the vehicle deflection test program in this Embodiment. It is a figure for demonstrating the deviation | shift amount from a straight locus | trajectory.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle deflection test apparatus 12 GPS apparatus 14 Output apparatus 16 Computer

Claims (9)

Acquisition means for acquiring position information indicating a current position of the vehicle;
Based on the position information acquired by the acquisition means, a travel locus is obtained when the vehicle travels for a predetermined time in a non-steered travel state in which the vehicle travels without steering, and the vehicle travels straight on the basis of the determined travel locus. Estimating means for estimating a straight traveling locus when
A calculating means for calculating a deviation amount from the straight traveling locus when the vehicle travels a predetermined distance in a non-steering traveling state after the predetermined time has elapsed;
A vehicle deflection test apparatus including:   The vehicle deflection test apparatus according to claim 1, wherein the acquisition unit acquires the position information based on a GPS satellite signal.   The vehicle deflection test apparatus according to claim 1, wherein the calculation unit calculates the deviation amount when the vehicle travels the predetermined distance by integrating the deviation amounts per unit time.   The vehicle deflection test apparatus according to any one of claims 1 to 3, wherein the predetermined time is in a range of 0.3 second to 2 seconds.   The vehicle deflection test apparatus according to claim 3 or 4, wherein the unit time is in a range of 0.01 seconds to 0.07 seconds. Computer
Acquisition means for acquiring position information indicating a current position of the vehicle;
Based on the position information acquired by the acquisition means, a travel locus is obtained when the vehicle travels for a predetermined time in a non-steered travel state in which the vehicle travels without steering, and the vehicle travels straight on the basis of the determined travel locus. Estimating means for estimating a straight traveling locus when
A calculating means for calculating a deviation amount from the straight traveling locus when the vehicle travels a predetermined distance in a non-steering traveling state after the predetermined time has elapsed;
Vehicle deflection test program to make it function.   A vehicle deflectability test program for causing a computer to function as each means constituting the vehicle deflectability test apparatus according to any one of claims 1 to 5. Obtaining position information indicating the current position of the vehicle;
When a travel locus is obtained when the vehicle travels for a predetermined time in a non-steered travel state in which the vehicle travels without steering based on the acquired position information, and the vehicle travels straight based on the obtained travel locus Estimating a straight trajectory of
Calculating an amount of deviation from the straight traveling locus when the vehicle has traveled a predetermined distance in a non-steering traveling state after the predetermined time has elapsed;
A vehicle deflection test method including:   The wheel alignment of the vehicle is fixed, different types of tires are mounted on the vehicle, and each step of the vehicle deflection test method according to claim 8 is performed for each of the tires, thereby A vehicle deflection test method for calculating a deviation amount.

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