Test structure and calibration method for commercial vehicle frame torsion angle calibration

Abstract

The present invention provides a test structure for calibrating the torsion angle of a commercial vehicle frame, characterized in that it includes a frame, a test platform, an angle measuring mechanism, a torsion mechanism and a supporting and fixing mechanism; the angle measuring mechanism is arranged between the longitudinal beams of the frame, and the measuring center of the angle measuring mechanism is arranged at the symmetric center of the two longitudinal beams of the frame measurement section. A calibration method is also provided, characterized in that by calibrating the static torsion angle, a calibrated static torsion angle displacement value corresponding to each static torsion angle is obtained; by calibrating the dynamic torsion angle, a calibrated dynamic amplitude displacement group corresponding to each dynamic torsion angle is obtained. The test structure and calibration method described in the present invention are used to calibrate the frame torsion angle, and the calibration result is accurate, which can improve the test accuracy of subsequent frame torsion load tests and improve the test efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of automobile manufacturing, in particular to a test structure and a calibration method for calibrating the torsion angle of a commercial vehicle frame. Background Art

[0002] The frame of a commercial vehicle usually needs to be subjected to a torsional load test during the design and manufacturing stage. The frame torsional load test refers to applying a certain load to the frame to twist the frame forward and backward to test the torsional stiffness and fatigue strength of the frame. In the prior art, the torsional test of the frame of a commercial vehicle usually uses a single actuator to apply a load on one side of the frame to cause the frame to generate a torsion angle. In fact, it is indirectly achieved by controlling the extension and retraction of the actuator to make the frame reach the corresponding torsion angle. During the actual test process, there is an inaccurate measurement of the torsion angle, and there is a difference between the theoretical displacement and the actual displacement of the actuator relative to a certain torsion angle, which leads to deviations or even distortions in the test or experimental results. Summary of the invention

[0003] In view of the problems in the background technology, the present invention provides a test structure for calibrating the torsion angle of a commercial vehicle frame, and a calibration method for the above-mentioned test structure, so as to solve the problems in the prior art of inaccurate frame torsion angle measurement and inaccurate actuator displacement corresponding to the frame torsion angle, which lead to deviation or even distortion of the frame torsion test results.

[0004] To achieve the purpose of the present invention, the present invention provides a test structure for calibrating the torsion angle of a commercial vehicle frame, and its innovative points are: comprising a frame, a test platform, an angle measuring mechanism, a torsion mechanism and a supporting and fixing mechanism; the bottom surface of the supporting and fixing mechanism is fixedly connected to the test platform, and the upper end of the supporting and fixing mechanism is fixedly connected to the lower side surface of the rear end of the frame; the angle measuring mechanism and the torsion mechanism are both arranged in a measuring section at the front of the frame;

[0005] The angle measuring mechanism comprises a crossbeam and an angle measuring instrument, both ends of the crossbeam are provided with connecting plates, the two ends of the crossbeam are respectively connected to the inner side surfaces of the webs of the two longitudinal beams of the frame through the connecting plates, the upper side surface of the crossbeam is parallel to the axial direction of the longitudinal beam, and the upper side surface of the crossbeam is perpendicular to the web of the longitudinal beam; the angle measuring instrument is fixedly arranged on the upper side surface of the middle part of the crossbeam;

[0006] The torsion mechanism includes a support base, a loading arm and an actuator; two supporting longitudinal beams are fixedly arranged on the upper side of the loading arm, the two supporting longitudinal beams are arranged in parallel with each other, and the axial direction of the supporting longitudinal beams is perpendicular to the axial direction of the loading arm; the axial direction of the loading arm is perpendicular to the axial direction of the longitudinal beams of the frame; the upper ends of the two supporting longitudinal beams are respectively fixedly connected to the lower parts of the two longitudinal beams of the frame; the bottom surface of the support base is fixedly connected to the top surface of the test platform, and the upper end of the support base is hinged to the middle part of the loading arm; the actuator is arranged on the outer side of the frame, the force-applying end of the actuator is fixedly connected to the upper side of the loading arm, and the axial direction of the actuator is arranged along the vertical direction.

[0007] Furthermore, the connecting plate is provided with an elongated hole, and the connecting plate is connected to the longitudinal beam of the frame by bolts through the elongated hole.

[0008] Furthermore, the measuring center of the angle measuring instrument is arranged directly above the geometric center of the cross beam, and the upper side surface of the cross beam coincides with the longitudinal center plane of the web of the longitudinal beam of the frame.

[0009] Furthermore, a first hinge seat is provided in the middle of the loading arm, a second hinge seat is provided in the upper part of the supporting base, and the first hinge seat is hinged to the second hinge seat.

[0010] The present invention also provides a calibration method for the frame torsion angle according to the above test structure, the calibration method comprising:

[0011] Assuming that the measuring section of the frame is in a horizontal state and the reading of the angle measuring instrument is 0°, the telescopic displacement of the actuator is the initial displacement; assuming that during the axial extension of the actuator starting from the initial displacement, the torsion direction of the frame is positive, the reading of the angle measuring instrument is a positive value, and the telescopic displacement of the actuator is a positive value; assuming that during the axial contraction of the actuator starting from the initial displacement, the torsion direction of the frame is negative, the reading of the angle measuring instrument is a negative value, and the telescopic displacement of the actuator is a negative value;

[0012] The calibration of the frame torsion angle includes the calibration of the static torsion angle and the calibration of the dynamic torsion angle; the static torsion angle of the frame is calibrated according to method one; the dynamic torsion angle of the frame is calibrated according to method two;

[0013] The method 1 comprises:

[0014] Assume that the range of the static torsion angle of the frame is -a to +a; Assume that the increment of the static torsion angle is b; Assume n×b=a, where n is the number of increments of the static torsion angle, n is an integer, and a, b and n are all set values;

[0015] 1) Perform system dynamic correction according to method 3;

[0016] 2) Control the actuator to extend at a uniform speed, so that the frame rotates in the positive direction. When the frame's torsion angle increases by b, a positive static torsion angle θ is obtained. i正 and the corresponding positive telescopic displacement S of the actuator i正 , so that the positive static torsion angle θ i正 The static torsion angle increment b is incremented n times until the positive static torsion angle θ i正 Reaching +a, that is, obtaining a total of n positive static torsion angles θ from +b to +a i正 and the corresponding n positive telescopic displacements S i正 , where i is an integer from 1 to n; each time the torsion angle increases by b, it takes t1 seconds, and each time the torsion angle increases by b, it pauses for t2 seconds before continuing the next torsion, and t1 and t2 are set values;

[0017] 3) Perform system dynamic correction according to method 3;

[0018] 4) Control the actuator to shrink at a constant speed, so that the frame rotates in the negative direction. When the frame's torsion angle increases by b, a negative static torsion angle θ is obtained. i负 and the corresponding negative telescopic displacement S of the actuator i负 , so that the negative static torsion angle θ i负 The static torsion angle increment b is incremented n times until the negative static torsion angle θ i负 Reaching -a, that is, obtaining a total of n negative static torsion angles θ from -b to -a i负 and the corresponding n negative expansion displacements S i负 ; Each time the torsion angle increases by b, it takes t1 seconds. After each torsion angle increases by b, there is a pause of t2 seconds before continuing the next torsion. The t1 and t2 are set values;

[0019] 5) Determine whether the number of executions from step 1) to step 4) reaches 3 times. If the number of executions is less than 3 times, return to step 1); if the number of executions is equal to 3 times, proceed to step 6);

[0020] 6) Each time from step 1) to step 4) is executed once, n θ i正 and θ i负 , and each θ i正 Each corresponding to 1 S i正 , and each θ i负 Each corresponding to 1 S i负 ; After executing step 1) to step 4) three times, we get each θ i正 The three Ss corresponding to each i正 , and each θ i负 The three Ss corresponding to eachi负 ;

[0021] Each θ i正 The three Ss corresponding to each i正 Taking the average value, we get i正 Calibrated positive static torsion displacement value; each θ i负 The three Ss corresponding to each i负 Taking the average value, we get i负 Calibrated negative static torsional displacement value;

[0022] The third method comprises:

[0023] Control the extension and retraction of the actuator and adjust the horizontal position of the frame so that the reading of the angle measuring instrument is 0°;

[0024] Then, the actuator is controlled to twist the frame x times with a sine wave having an amplitude of k and a frequency of p; wherein k, p and x are all set values;

[0025] Then reset the reading of the angle measuring instrument to zero;

[0026] The second method comprises:

[0027] Assume that the maximum dynamic torsion angle of the frame is ±c; Assume that the increment of the single dynamic torsion angle is ±d; Assume that m×d=c, where m is the number of times the dynamic torsion angle is incremented, m is an integer, and c, d and m are all set values;

[0028] A) Control and adjust the actuator to reciprocate at a frequency f, gradually increase the dynamic torsion angle of the frame, and obtain a dynamic torsion angle to be calibrated ±θ every time the dynamic torsion angle increases ±d j and the corresponding two dynamic amplitude displacements S of the actuator j正 and S j负 , where j is an integer from 1 to m, S j正 is a positive value, S j负 is a negative value; the single ±θ j The corresponding two dynamic amplitude displacements S j正 and S j负 is recorded as a dynamic amplitude displacement group; until the dynamic torsion angle of the frame increases to ±c, m ±θ are obtained. j and corresponding m dynamic amplitude displacement groups; where frequency f is the set value;

[0029] B) Repeat step A) until step A) is performed 3 times, so that each dynamic torsion angle to be calibrated ±θ j Obtain three corresponding dynamic amplitude displacement groups;

[0030] C) each of the dynamic torsion angles to be calibrated ±θ jThe three corresponding dynamic amplitude displacement groups are processed in the following way, so that each dynamic torsion angle ±θ to be calibrated is obtained. j The corresponding calibrated dynamic amplitude displacement group:

[0031] The single ±θ j The corresponding three S j正 Take the average value to get S j正标 , the single ±θ j The corresponding three S j负 Take the average value to get S j负标 , a single ±θ j The corresponding S j正标 and S j正标 That is, a corresponding calibrated dynamic amplitude displacement group is formed.

[0032] The principle of the present invention is as follows:

[0033] The inventor discovered during the torsion load test of the frame that in the prior art, an angle measuring instrument is usually placed on the upper wing surface of the frame longitudinal beam to detect the torsion angle of the frame. However, due to the influence of the manufacturing process, the bending angles of the wing surfaces of the left and right longitudinal beams of the frame (the standard bending angle between the wing surface and the belly surface of the beam is theoretically 90°) are different from the theoretical values. Therefore, for the same torsion angle, the torsion angle values ​​measured on the left and right wing surfaces are not consistent. In fact, the torsion angle obtained by this measurement method itself is different from the torsion angle required for the test. Ideally, the torsion center of the frame should be on the symmetric plane of the two longitudinal beams of the frame along the transverse direction, so the torsion angle value measured in the above manner has a large error. On the other hand, the torsion angle of the frame can also be indirectly calculated through the telescopic displacement value of the actuator and the length of the torque arm. However, in fact, due to the differences in the structure of the frames of different models, the diversity of the suspension system structure, the matching accuracy of the frame, suspension system and torsion bench fixture, and the structure and inertia of the torsion bench system itself, there is a large difference between the frame torsion angle obtained by theoretical calculation of the telescopic displacement value of the same actuator and the actual torsion angle. The above errors are all factors that cause deviation or even distortion of the data obtained from the torsion load test.

[0034] Through research, the inventors have designed the test structure described in the present invention, and used the test structure to adopt the method described in the present invention to calibrate the static and dynamic torsion angles of the frame, thereby obtaining the actuator displacement values ​​corresponding to each torsion angle, that is, establishing a corresponding relationship between the actuator displacement value and the torsion angle of the frame. When the torsion test of the frame is actually carried out, there is no need to measure the torsion angle. It is only necessary to control the actuator to reach the calibrated telescopic displacement to obtain the corresponding torsion angle value parameter, which can eliminate the above-mentioned influencing factors to the greatest extent, improve the accuracy of the test data, and improve the test efficiency.

[0035] It can be seen that the present invention has the following beneficial effects: the use of the test structure and calibration method described in the present application can improve the data accuracy of the frame torsion angle, thereby improving the data accuracy of the entire torsion test. At the same time, since the torsion angle is no longer measured separately, the test process is simplified and the test efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings of the present invention are as follows.

[0037] Attached Figure 1 It is a structural schematic diagram of the present invention;

[0038] Attached Figure 2 It is a schematic diagram of the cross-sectional structure of the measuring section;

[0039] Attached Figure 3 For attachment Figure 2 AA section view.

[0040] In the figure: 1. frame; 2. test platform; 3. angle measuring mechanism; 4. torsion mechanism; 5. support and fixing mechanism; 31. cross beam; 32. angle measuring instrument; 33. connecting plate; 41. support base; 42. loading arm; 43. actuator; 44. support longitudinal beam; 411. second hinge seat; 421. first hinge seat. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the embodiments.

[0042] As attached Figure 1The test structure shown for calibrating the torsion angle of a commercial vehicle frame includes a frame 1, a test platform 2, an angle measuring mechanism 3, a torsion mechanism 4 and a supporting and fixing mechanism 5; the bottom surface of the supporting and fixing mechanism 5 is fixedly connected to the test platform 2, and the upper end of the supporting and fixing mechanism 5 is fixedly connected to the lower side surface of the rear end of the frame 1; the supporting and fixing mechanism described in the present invention is mainly used to fix the rear end of the frame, so that during the torsion test, the measuring section of the frame is torsion relative to the rear end of the frame, and the supporting and fixing mechanism can adopt the structure in the prior art; the angle measuring mechanism 3 and the torsion mechanism 4 are both arranged in the measuring section at the front of the frame 1, and are used to apply torque to the measuring section and measure the torsion angle.

[0043] As attached Figure 2 As shown, the angle measuring mechanism 3 includes a crossbeam 31 and an angle measuring instrument 32. Both ends of the crossbeam 31 are provided with connecting plates 33. The two ends of the crossbeam 31 are respectively connected to the inner side surfaces of the webs of the two longitudinal beams of the frame 1 through the connecting plates 33. The upper side surface of the crossbeam 31 is parallel to the axial direction of the longitudinal beam, and the upper side surface of the crossbeam 31 is perpendicular to the webs of the longitudinal beams. The angle measuring instrument 32 is fixedly arranged on the upper side surface of the middle part of the crossbeam 31. In order to more accurately measure the torsion angle of the frame measurement section, the measurement center of the angle measuring instrument 32 is arranged directly above the geometric center of the crossbeam 31, and the upper side surface of the crossbeam 31 coincides with the longitudinal center plane of the web of the longitudinal beam of the frame 1. In order to facilitate the adjustment of the position of the angle measuring instrument during installation, a long hole is arranged on the connecting plate 33, and the connecting plate 33 is bolted to the longitudinal beam of the frame 1 through the long hole. The torsion angle measured by the angle measuring instrument at this position is consistent with the ideal torsion angle, overcoming the large error caused by measuring on the wing surface of the frame longitudinal beam and making the calibration of the torsion angle more accurate.

[0044] The torsion mechanism 4 includes a support base 41, a loading arm 42 and an actuator 43; two support longitudinal beams 44 are fixedly arranged on the upper side of the loading arm 42, and the two support longitudinal beams 44 are arranged in parallel with each other, and the axial direction of the support longitudinal beam 44 is perpendicular to the axial direction of the loading arm 42; the axial direction of the loading arm 42 is perpendicular to the axial direction of the longitudinal beam of the frame 1; the upper ends of the two support longitudinal beams 44 are respectively fixedly connected to the lower parts of the two longitudinal beams of the frame 1; the bottom surface of the support base 41 is fixedly connected to the top surface of the test platform 2, and the upper end of the support base 41 is hinged to the middle part of the loading arm 42. In this embodiment, as shown in the attached Figure 3As shown, a first hinge seat 421 is provided in the middle of the loading arm 42, a second hinge seat 411 is provided on the upper part of the supporting base 41, and the first hinge seat 421 is hinged to the second hinge seat 411; the actuator 43 is provided on the outer side of the frame 1, the force-applying end of the actuator 43 is fixedly connected to the upper side surface of the loading arm 42, and the axial direction of the actuator 43 is provided along the vertical direction.

[0045] The present invention also provides a calibration method for the frame torsion angle according to the above test structure. In the prior art, when performing a torsion test on a frame, static torsion load and dynamic torsion load tests are included. The former is mainly used to test the stiffness of the frame, and the latter is mainly used to test the fatigue strength of the frame. Therefore, the calibration of the frame torsion angle is also divided into the calibration of the static torsion angle and the calibration of the dynamic torsion angle.

[0046] The calibration method comprises:

[0047] Assuming that the measuring section of the frame 1 is in a horizontal state and the reading of the angle measuring instrument 32 is 0°, the telescopic displacement of the actuator 43 is the initial displacement; assuming that during the axial extension of the actuator 43 starting from the initial displacement, the torsion direction of the frame 1 is positive, the reading of the angle measuring instrument 32 is a positive value, and the telescopic displacement of the actuator 43 is a positive value; assuming that during the axial contraction of the actuator 43 starting from the initial displacement, the torsion direction of the frame 1 is negative, the reading of the angle measuring instrument 32 is a negative value, and the telescopic displacement of the actuator 43 is a negative value;

[0048] The calibration of the torsion angle of the frame 1 includes the calibration of the static torsion angle and the calibration of the dynamic torsion angle; the static torsion angle of the frame 1 is calibrated according to method 1; the dynamic torsion angle of the frame 1 is calibrated according to method 2;

[0049] The method 1 comprises:

[0050] Assume that the range of the static torsion angle of the frame 1 is -a to +a; Assume that the increment of the static torsion angle of a single time is b; Assume n×b=a, wherein n is the number of times the static torsion angle is incremented, n is an integer, and a, b and n are all set values; the range of the static torsion angle is usually set according to the torsion angle range of the static torsion load test, for example, if the torsion angle range of the static torsion load test is ±5°, then the range of the static torsion angle during the calibration test is also ±5°; the increment of the static torsion angle is b, which is usually half of the increment of the torsion angle of the static torsion load test, for example, if the torsion angle increment of the static torsion load test is 1°, then the increment of the static torsion angle b during the calibration test is 0.5°;

[0051] 1) Perform system dynamic correction according to method 3;

[0052] 2) Control the actuator 43 to extend at a constant speed, so that the frame 1 rotates in the positive direction. When the torsion angle of the frame 1 increases by b, a positive static torsion angle θ is obtained. i正 and the corresponding positive telescopic displacement S of the actuator 43 i正 , so that the positive static torsion angle θ i正 The static torsion angle increment b is incremented n times until the positive static torsion angle θ i正 Reaching +a, that is, obtaining a total of n positive static torsion angles θ from +b to +a i正 and the corresponding n positive telescopic displacements S i正 , where i is an integer from 1 to n; each time the torsion angle increases by b, it takes t1 seconds, and each time the torsion angle increases by b, it pauses for t2 seconds before continuing the next torsion. The t1 and t2 are set values. In this embodiment, t1 is set to 20 seconds and t2 is set to 15 seconds;

[0053] 3) Perform system dynamic correction according to method 3;

[0054] 4) Control the actuator 43 to contract at a constant speed, so that the frame 1 rotates in the negative direction. When the torsion angle of the frame 1 increases by b, a negative static torsion angle θ is obtained. i负 and the corresponding negative telescopic displacement S of the actuator 43 i负 , so that the negative static torsion angle θ i负 The static torsion angle increment b is incremented n times until the negative static torsion angle θ i负 Reaching -a, that is, obtaining a total of n negative static torsion angles θ from -b to -a i负 and the corresponding n negative expansion displacements S i负 ; Each time the torsion angle increases by b, it takes t1 seconds. After each torsion angle increases by b, there is a pause of t2 seconds before continuing the next torsion. The t1 and t2 are set values;

[0055] 5) Determine whether the number of executions from step 1) to step 4) reaches 3 times. If the number of executions is less than 3 times, return to step 1); if the number of executions is equal to 3 times, proceed to step 6);

[0056] 6) Each time from step 1) to step 4) is executed once, n θ i正 and θ i负 , and each θ i正 Each corresponding to 1 S i正 , and each θ i负 Each corresponding to 1 S i负 ; After executing step 1) to step 4) three times, we can get each θ i正 The three Ss corresponding to each i正 , and each θ i负 The three Ss corresponding to each i负;

[0057] Each θ i正 The three Ss corresponding to each i正 Taking the average value, we get i正 Calibrated positive static torsion displacement value; each θ i负 The three Ss corresponding to each i负 Taking the average value, we get i负 Calibrated negative static torsional displacement value;

[0058] In fact, the calibration is performed three times by repeating the above steps, so that each torsion angle obtains three corresponding actuator displacement values, and then the average of the three displacement values ​​is taken to obtain the final calibration result, so as to minimize the measurement error and improve the calibration accuracy.

[0059] The third method comprises:

[0060] Control the actuator 43 to extend and retract, and adjust the horizontal position of the frame 1 so that the reading of the angle measuring instrument 32 is 0°;

[0061] Then, the actuator 43 is controlled to twist the frame 1 x times with a sine wave having an amplitude of k and a frequency of p; the k, p and x are all set values, which can be set according to the needs or experience of the torsion test, wherein the amplitude k is usually set to 1 / 2 of the actuator displacement value corresponding to the maximum torsion angle of the frame during the torsion test, for example: when the maximum torsion angle of the frame reaches +5° during the torsion test, the displacement of the actuator is +60mm, then k can be ±30mm; the frequency p can be the frequency during the dynamic torsion load test, such as 0.5Hz, the number of twists can be 20-50 times, and the torsion of the frame in the positive or negative direction is calculated as 1 twist;

[0062] Then the reading of the angle measuring instrument 32 is reset to zero;

[0063] By dynamically correcting the system through the above steps, the influence of elastic deformation of the test structure during construction and use, as well as the structure and inertia of the system itself, can be eliminated, so that the entire calibration test system reaches a balanced state. Then, the calibration test can be carried out, which can also eliminate structural errors to the greatest extent and improve the accuracy of the calibration test.

[0064] The second method comprises:

[0065] Assume that the maximum dynamic torsion angle of the frame 1 is ±c; Assume that the increment of the single dynamic torsion angle is ±d; Assume that m×d=c, wherein m is the number of times the dynamic torsion angle is incremented, m is an integer, and c, d and m are all set values; the value-taking method here is similar to the method of static torsion angle calibration, for example, the torsion angle range of the dynamic torsion load test is ±5°, then the range of the dynamic torsion angle during the calibration test is also ±5°; the dynamic torsion angle increment is ±d, which is usually half of the torsion angle increment of the dynamic torsion load test, for example, the torsion angle increment of the dynamic torsion load test is ±1°, then the dynamic torsion angle increment d during the calibration test is ±0.5°, if the dynamic torsion angle increases by ±0.5°, ±1°, ±1.5°...;

[0066] A) Control and adjust the actuator 43 to reciprocate at a frequency f, gradually increase the dynamic torsion angle of the frame 1, and obtain a dynamic torsion angle to be calibrated ±θ every time the dynamic torsion angle increases ±d j and the corresponding two dynamic amplitude displacements S of the actuator 43 j正 and S j负 , where j is an integer from 1 to m, S j正 is a positive value, S j负 is a negative value due to the structural errors of the frame and system. j正 and S j负 It is not necessarily a positive or negative symmetrical value; j The corresponding two dynamic amplitude displacements S j正 and S j负 is recorded as a dynamic amplitude displacement group; until the dynamic torsion angle of the frame 1 increases to ±c, m ±θ are obtained. j and the corresponding m dynamic amplitude displacement groups; wherein the frequency f is the set value. Usually, the calibration results obtained by using different frequencies f are different. The value of the frequency f in the calibration test should be consistent with the frequency used in the dynamic torsion load test.

[0067] B) Repeat step A) until step A) is performed 3 times, so that each dynamic torsion angle to be calibrated ±θ j The corresponding three dynamic amplitude displacement groups are obtained;

[0068] C) each of the dynamic torsion angles to be calibrated ±θ j The corresponding three dynamic amplitude displacement groups are processed in the following way, that is, each dynamic torsion angle ±θ to be calibrated is obtained j The corresponding calibrated dynamic amplitude displacement group:

[0069] The single ±θ j The corresponding three S j正 Take the average value to get S j正标 , the single ±θj The corresponding three S j负 Take the average value to get S j负标 , a single ±θ j The corresponding S j正标 and S j正标 That is, a corresponding calibrated dynamic amplitude displacement group is formed.

[0070] As with the calibration of the static torsion angle, three repeated calibration tests are performed to obtain three corresponding actuator dynamic amplitude displacement groups for each dynamic torsion angle to be calibrated. The average of these three dynamic amplitude displacement groups is taken to obtain the final calibration result, in order to minimize the measurement error and improve the calibration accuracy.

Claims

1. A method for calibrating the torsion angle of a commercial vehicle frame, characterized in that: The hardware involved includes: a vehicle frame (1), a test platform (2), an angle measuring mechanism (3), a torsion mechanism (4) and a support and fixing mechanism (5); the bottom surface of the support and fixing mechanism (5) is fixedly connected to the test platform (2), and the upper end of the support and fixing mechanism (5) is fixedly connected to the lower side surface of the rear end of the vehicle frame (1); the angle measuring mechanism (3) and the torsion mechanism (4) are both arranged in the measuring section at the front of the vehicle frame (1); The angle measuring mechanism (3) comprises a crossbeam (31) and an angle measuring instrument (32), both ends of the crossbeam (31) are provided with connecting plates (33), the two ends of the crossbeam (31) are respectively connected to the inner side surfaces of the webs of two longitudinal beams of the frame (1) through the connecting plates (33), the upper side surface of the crossbeam (31) is parallel to the axial direction of the longitudinal beam, and the upper side surface of the crossbeam (31) is perpendicular to the webs of the longitudinal beam; the angle measuring instrument (32) is fixedly arranged on the upper side surface of the middle part of the crossbeam (31); The torsion mechanism (4) comprises a support base (41), a loading arm (42) and an actuator (43); two supporting longitudinal beams (44) are fixedly arranged on the upper side of the loading arm (42); the two supporting longitudinal beams (44) are arranged parallel to each other, and the axial direction of the supporting longitudinal beam (44) is perpendicular to the axial direction of the loading arm (42); the axial direction of the loading arm (42) is perpendicular to the axial direction of the longitudinal beam of the frame (1); the upper ends of the two supporting longitudinal beams (44) are respectively The support base (41) is fixedly connected to the lower part of the two longitudinal beams of the vehicle frame (1); the bottom surface of the support base (41) is fixedly connected to the top surface of the test platform (2), and the upper end of the support base (41) is hinged to the middle part of the loading arm (42); the actuator (43) is arranged on the outer side of the vehicle frame (1), the force-applying end of the actuator (43) is fixedly connected to the upper side surface of the loading arm (42), and the axial direction of the actuator (43) is arranged along the vertical direction; The calibration method comprises: Assuming that the measuring section of the frame (1) is in a horizontal state and the reading of the angle measuring instrument (32) is 0°, the telescopic displacement of the actuator (43) is the initial displacement; assuming that during the process of the actuator (43) extending axially with the initial displacement as the starting point, the torsion direction of the frame (1) is positive, the reading of the angle measuring instrument (32) is a positive value, and the telescopic displacement of the actuator (43) is a positive value; assuming that during the process of the actuator (43) contracting axially with the initial displacement as the starting point, the torsion direction of the frame (1) is negative, the reading of the angle measuring instrument (32) is a negative value, and the telescopic displacement of the actuator (43) is a negative value; The calibration of the torsion angle of the frame (1) includes the calibration of the static torsion angle and the calibration of the dynamic torsion angle; the calibration of the static torsion angle of the frame (1) is performed according to method one; the calibration of the dynamic torsion angle of the frame (1) is performed according to method two; The method 1 comprises: Assume that the static torsion angle of the frame (1) ranges from -a to +a; assume that the increment of the static torsion angle is b; assume that n×b=a, wherein n is the number of increments of the static torsion angle, n is an integer, and a, b and n are all set values; 1) Perform system dynamic correction according to method 3; 2) Control the actuator (43) to extend at a constant speed, so that the frame (1) rotates in the positive direction. When the torsion angle of the frame (1) increases by b, a positive static torsion angle θ is obtained. i正 and the corresponding positive telescopic displacement S of the actuator (43) i正 , so that the positive static torsion angle θ i正 The static torsion angle increment b is incremented n times until the positive static torsion angle θ i正 Reaching +a, that is, obtaining a total of n positive static torsion angles θ from +b to +a i正 and the corresponding n positive telescopic displacements S i正 , where i is an integer from 1 to n; each time the torsion angle increases by b, it takes t1 seconds, and each time the torsion angle increases by b, it pauses for t2 seconds before continuing the next torsion, and t1 and t2 are set values; 3) Perform system dynamic correction according to method 3; 4) Control the actuator (43) to contract at a uniform speed, so that the frame (1) rotates in the negative direction. When the torsion angle of the frame (1) increases by b, a negative static torsion angle θ is obtained. i负 and the corresponding negative telescopic displacement S of the actuator (43) i负 , so that the negative static torsion angle θ i负 The static torsion angle increment b is incremented n times until the negative static torsion angle θ i负 Reaching -a, that is, obtaining a total of n negative static torsion angles θ from -b to -a i负 and the corresponding n negative expansion displacements S i负 ; Each time the torsion angle increases by b, it takes t1 seconds. After each torsion angle increases by b, there is a pause of t2 seconds before continuing the next torsion. The t1 and t2 are set values; 5) Determine whether the number of executions from step 1) to step 4) reaches 3 times. If the number of executions is less than 3 times, return to step 1); if the number of executions is equal to 3 times, proceed to step 6); 6) Each time from step 1) to step 4) is executed once, n θ i正 and θ i负 , and each θ i正 Each corresponding to 1 S i正 , and each θ i负 Each corresponding to 1 S i负 ; After executing step 1) to step 4) three times, we get each θ i正 The three Ss corresponding to each i正 , and each θ i负 The three Ss corresponding to each i负 ; Each θ i正 The three Ss corresponding to each i正 Taking the average value, we get i正 Calibrated positive static torsion displacement value; each θ i负 The three Ss corresponding to each i负 Taking the average value, we get i负 Calibrated negative static torsional displacement value; The third method comprises: Controlling the actuator (43) to extend and retract, adjusting the horizontal position of the frame (1) so that the reading of the angle measuring instrument (32) is 0°; Then, the actuator (43) is controlled to twist the frame (1) x times with a sine wave having an amplitude of k and a frequency of p; k, p and x are all set values; Then the reading of the angle measuring instrument (32) is reset to zero; The second method comprises: Assume that the maximum dynamic torsion angle of the frame (1) is ±c; Assume that the increment of the single dynamic torsion angle is ±d; Assume that m×d=c, wherein m is the number of times the dynamic torsion angle is incremented, m is an integer, and c, d and m are all set values; A) controlling and adjusting the actuator (43) to reciprocate at a frequency f, gradually increasing the dynamic torsion angle of the frame (1), wherein each increase of the dynamic torsion angle by ±d results in a dynamic torsion angle ±θ to be calibrated j and the corresponding two dynamic amplitude displacements S of the actuator (43) j正 and S j负 , where j is an integer from 1 to m, S j正 is a positive value, S j负 is a negative value; the single ±θ j The corresponding two dynamic amplitude displacements S j正 and S j负 is recorded as a dynamic amplitude displacement group; until the dynamic torsion angle of the frame (1) increases to ±c, m ±θ are obtained. j and corresponding m dynamic amplitude displacement groups; where frequency f is the set value; B) Repeat step A) until step A) is performed 3 times, so that each dynamic torsion angle to be calibrated ±θ j Obtain three corresponding dynamic amplitude displacement groups; C) each of the dynamic torsion angles to be calibrated ±θ j The three corresponding dynamic amplitude displacement groups are processed in the following way, so that each dynamic torsion angle ±θ to be calibrated is obtained. j The corresponding calibrated dynamic amplitude displacement group: The single ±θ j The corresponding three S j正 Take the average value to get S j正标 , the single ±θ j The corresponding three S j负 Take the average value to get S j负标 , a single ±θ j The corresponding S j正标 and S j正标 That is, a corresponding calibrated dynamic amplitude displacement group is formed.

2. The method for calibrating the torsion angle of a commercial vehicle frame according to claim 1, characterized in that: The connecting plate (33) is provided with an elongated hole, and the connecting plate (33) is connected to the longitudinal beam of the vehicle frame (1) via bolts through the elongated hole.

3. The method for calibrating the torsion angle of a commercial vehicle frame according to claim 1 or 2, characterized in that: The measuring center of the angle measuring instrument (32) is arranged directly above the geometric center of the cross beam (31), and the upper side surface of the cross beam (31) coincides with the longitudinal center plane of the web of the longitudinal beam of the vehicle frame (1).

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