Pedal travel data correction method in brake system test

Abstract

The invention relates to a data correction method for a pedal travel in a brake system test. The data correction method comprises the following steps of: restoring a stay wire end of a pedal travel sensor to an initial position; fixing a pedal travel sensor body on a lower shield of a steering wheel, fixing a stay wire end on a brake pedal and keeping the stay wire end horizontally flush with a load point, and recording a measured value of the pedal travel at the moment; the brake pedal is treaded until the brake pressure reaches a set value, the value of the pedal stroke at the moment is recorded, and the brake pedal is released and returns to the initial position; a sensor is installed at a certain distance along the approximately vertical direction of the lower shield of the steering wheel, and the measured value of the pedal travel is recorded; stepping on a brake pedal until the brake pressure reaches a set value, and recording the value of the pedal travel at the moment; and correcting. According to the method, the accuracy of the brake pedal travel measurement result in the brake system test can be effectively ensured, and the development and verification of the brake system are facilitated; the method can be applied to Besturn NAT vehicle models and can be continued to other subsequent vehicle models.

Description

Technical Field

[0001] The invention belongs to the technical field of automobiles, and in particular relates to a data correction method for a pedal stroke in a brake system test. Background Art

[0002] The brake pedal travel of a vehicle generally refers to the displacement of the load point on the brake pedal during the braking process. The actual motion trajectory of the load point is an arc line. Since the radius of the arc line is large and the rotation angle is small, the length difference between the arc line and its chord length is small. Therefore, the straight-line distance between the load point at the initial position of the brake pedal and the end position of the brake pedal is generally taken as the pedal travel.

[0003] In the braking system test, the brake pedal stroke is an essential measurement parameter and a key parameter to characterize the brake system pedal feel performance. Therefore, the accuracy of the brake pedal stroke measurement must be ensured in the braking system test. In the braking system test, a pull-wire travel sensor is generally used to measure the pedal stroke. The sensor body is fixed on the lower guard of the steering wheel, and one end of the pull wire is fixed on the brake pedal. When braking, the pull wire stretches as the brake pedal moves downward, and then the movement displacement of the brake pedal, that is, the pedal stroke, is measured.

[0004] In actual application, because the fixed position of the sensor body is generally not on the track line of the brake pedal movement, there is a certain deviation between the measured value of the sensor and the actual value of the pedal stroke. Figure 1 As shown, the measured value of the pedal stroke by the pedal stroke sensor is (KL), and the actual value of the pedal stroke is S. According to the principle of the length of the three sides of a triangle, S>KL.

[0005] In order to ensure the accuracy of the measurement results, the measurement data needs to be corrected. However, there is currently no effective data correction method in the industry. Summary of the invention

[0006] The purpose of the present invention is to provide a method for correcting pedal stroke data in a brake system test, so as to solve the problem of ensuring the accuracy of brake pedal stroke measurement results in a brake system test.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A method for correcting pedal stroke data in a brake system test comprises the following steps: firstly restoring a pedal stroke sensor to an initial position, then determining the initial position of the pedal stroke sensor, then determining the pedal position at a brake pressure of 6 MPa, and finally perfecting a correction formula to correct the pedal stroke data.

[0009] Further, the following steps are included:

[0010] A. Return the cable end of the pedal travel sensor to its initial position and reset the displayed value to zero;

[0011] B. Fix the pedal travel sensor body on the steering wheel lower shield, fix the cable end on the brake pedal and keep it horizontally flush with the load point, record the measured value of the pedal travel at this time, recorded as L0, this position is the initial position of the sensor P0;

[0012] C. Depress the brake pedal until the brake pressure reaches the set value, record the value of the pedal stroke at this time, record it as K0, release the brake pedal and let it return to the initial position;

[0013] D. Install the sensor at a distance approximately vertical to one end of the steering wheel lower guard, record this distance as a, and record the measured value of the pedal stroke at this time, record it as L1. This position is the initial position of the sensor P1;

[0014] E. Press the brake pedal until the brake pressure reaches the set value, and record the value of the pedal stroke at this time, which is recorded as K1;

[0015] F. Amendment:

[0016] Assume that the measured value of the pedal stroke at a certain braking moment is x, and the actual value of the pedal stroke at that moment is f(x), then the following formula is used to correct the pedal stroke data:

[0017]

[0018] Furthermore, in step A, the wire end is restored to an initial position, i.e., position 0.

[0019] Furthermore, in step B, it is necessary to ensure that the pull wire is parallel to the plane where the motion trajectory of the load point is located.

[0020] Furthermore, the plane where the motion trajectory of the load point is located is generally the Y plane of the entire vehicle.

[0021] Furthermore, in step C and step E, when the brake pressure reaches 6 MPa, the value of the pedal stroke at this time is recorded.

[0022] Furthermore, in step D, a is greater than 20 mm, ensuring that the pull wire is parallel to the plane where the motion trajectory of the load point lies.

[0023] A car uses the data correction method of pedal stroke in a brake system test to perform data correction.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The data correction method of the pedal stroke in the brake test of the present invention can effectively ensure the accuracy of the brake pedal stroke measurement result in the brake system test, which is beneficial to the development and verification of the brake system; it can be applied to the Pentium NAT model and can be extended to other subsequent models. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 Schematic diagram of pedal travel measurement;

[0028] Figure 2 Schematic diagram of data correction of pedal travel in brake system test;

[0029] Figure 3 A flow chart of the steps of a method for correcting pedal travel data in a brake system test according to the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with embodiments:

[0031] The data correction method of the pedal stroke in the brake system test of the present invention is as follows: Figure 3 As shown, the following steps are included:

[0032] 1. Return the cable end of the pedal travel sensor to its initial position, i.e., position 0, and reset the displayed value to zero.

[0033] 2. Fix the pedal travel sensor body on the lower guard of the steering wheel, fix the cable end on the brake pedal and keep it horizontally flush with the load point. At the same time, ensure that the cable is parallel to the plane where the load point motion trajectory is located, record the measured value of the pedal travel at this time, record it as L0, and this position is the initial position P0 of the sensor. Among them, the plane where the load point motion trajectory is located is generally the Y plane of the whole vehicle.

[0034] 3. Depress the brake pedal until the brake pressure reaches 6MPa, and record the value of the pedal stroke at this time, which is recorded as K0. Release the brake pedal and let it return to the initial position.

[0035] 4. Install the sensor at a distance from one end of the steering wheel shield in the approximate vertical direction. This distance is recorded as a. Generally, a is greater than 20 mm. Ensure that the pull line is parallel to the plane where the load point motion trajectory is located. Record the measured value of the pedal stroke at this time, recorded as L1. This position is the initial position of the sensor P1.

[0036] 5. Depress the brake pedal until the brake pressure reaches 6MPa and record the value of the pedal travel at this time, which is recorded as K1.

[0037] 6. Correction.

[0038] Assume that the measured value of the pedal stroke at a certain braking moment is x, and the actual value of the pedal stroke at that moment is f(x), then the following formula is used to correct the pedal stroke data:

[0039]

[0040] The process of correcting the pedal stroke data in the present invention is: firstly restore the pedal stroke sensor to the initial position, then determine the initial position of the pedal stroke sensor, then determine the pedal position at 6MPa braking pressure, and finally improve the correction formula.

[0041] Example 1

[0042] A method for correcting pedal stroke data in a brake system test is applied to a Pentium NAT model. Taking the measured data of the brake pedal stroke of the NAT model as an example, data correction is performed as follows:

[0043] 1. Restore the cable end of the pedal travel sensor to its initial position, i.e., position 0, and reset the displayed value to zero.

[0044] 2. Install the pedal travel sensor according to the above requirements.

[0045] Fix the pedal travel sensor body on the steering wheel lower shield, fix the cable end on the brake pedal and keep it horizontally flush with the load point. At the same time, ensure that the cable is parallel to the plane where the load point motion trajectory is located, that is, the vehicle Y plane, and record the measured value of the pedal travel at this time, recorded as L0, L0 = 208.1mm.

[0046] 3. Depress the brake pedal until the brake pressure reaches 6MPa, and record the pedal stroke value K0 = 243mm. Release the brake pedal and return it to its initial position.

[0047] 4. Move the pedal travel sensor installation position along the steering wheel lower guard in an approximately vertical direction, ensuring that the cable is parallel to the plane where the load point motion trajectory is located, a = 49mm. Record the measured value of the pedal travel L1 = 214.5mm.

[0048] 5. Depress the brake pedal until the brake pressure reaches 6MPa and record the pedal stroke value K1=252mm.

[0049] 6. Improve the correction formula and get

[0050]

[0051] If the brake pedal travel value measured at a certain braking moment is 30 mm, then the actual value of the pedal travel at this moment is 33.95 mm.

[0052] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for correcting pedal stroke data in a brake system test, characterized in that: The following steps are involved: First restore the pedal travel sensor to its initial position, then determine the initial position of the pedal travel sensor, then determine the pedal position at 6MPa braking pressure, and finally improve the correction formula to correct the pedal travel data.

2. The method for correcting pedal stroke data in a brake system test according to claim 1, characterized in that: The following steps are involved: A. Return the cable end of the pedal travel sensor to its initial position and reset the displayed value to zero; B. Fix the pedal travel sensor body on the steering wheel lower shield, fix the cable end on the brake pedal and keep it horizontally flush with the load point, record the measured value of the pedal travel at this time, recorded as L0, this position is the initial position of the sensor P0; C. Depress the brake pedal until the brake pressure reaches the set value, record the value of the pedal stroke at this time, record it as K0, release the brake pedal and let it return to the initial position; D. Install the sensor at a distance approximately vertical to one end of the steering wheel lower guard, record this distance as a, and record the measured value of the pedal stroke at this time, record it as L1. This position is the initial position of the sensor P1; E. Press the brake pedal until the brake pressure reaches the set value, and record the value of the pedal stroke at this time, which is recorded as K1; F. Amendment: Assume that the measured value of the pedal stroke at a certain braking moment is x, and the actual value of the pedal stroke at that moment is f(x), then the following formula is used to correct the pedal stroke data:

3. The method for correcting pedal stroke data in a brake system test according to claim 1, characterized in that: Step A, the wire end is restored to the initial position, i.e., position 0.

4. The method for correcting pedal stroke data in a brake system test according to claim 1, characterized in that: In step B, it is necessary to ensure that the pull line is parallel to the plane where the motion trajectory of the load point lies.

5. The method for correcting pedal stroke data in a brake system test according to claim 4, characterized in that: The plane where the load point motion trajectory lies is generally the Y plane of the vehicle.

6. The method for correcting pedal stroke data in a brake system test according to claim 1, characterized in that: In step C and step E, when the brake pressure reaches 6 MPa, the value of the pedal stroke at this time is recorded.

7. The method for correcting pedal stroke data in a brake system test according to claim 1, characterized in that: Step D, a is greater than 20 mm, ensuring that the pull wire is parallel to the plane where the load point motion trajectory lies.

8. A car, characterized in that: Data correction is performed using a data correction method for pedal stroke in a brake system test as described in any one of claims 1 to 7.

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