CN114923987B - A vehicle-mounted mobile excitation device for rail modal testing - Google Patents

Abstract

A portable excitation device of on-vehicle for rail modal test solves the test efficiency that prior art exists low, and manpower and time cost are high, and vibration information transmission path is complicated, influences the problem that test accuracy, practicality are poor. The vehicle-mounted driving mechanism comprises a moving base, wherein a traveling roller of the vehicle-mounted driving mechanism is rotationally connected with the moving base through a roller rotating shaft, and a rotating shaft driving gear arranged on the roller rotating shaft is connected with a traveling driving motor; base lifting mechanisms are respectively arranged on two sides of the front end and the rear end of the movable base; the two sides of the middle part of the movable base are symmetrically provided with overturning excitation mechanisms respectively, and the movable base is provided with a hydraulic pump station and an exciter air supply system. The device has reasonable design and compact structure, can realize the change of the vertical and transverse excitation directions of the steel rail, can meet the requirements of the correlation analysis of excitation of different directions and different-order vibration of the specific steel rail, can quickly detect the corresponding damage of the steel rail, and has strong practicability and reliable use.

Description

A vehicle-mounted mobile excitation device for rail modal testing

Technical Field

The present invention belongs to the technical field of railway track engineering, and specifically relates to a vehicle-mounted mobile excitation device for rail modal testing, which can realize the change of vertical and lateral excitation direction of rails, meet the relevant analysis of different direction excitations and different order vibrations of specific rails, quickly detect corresponding damage of rails, has strong practicality, and is reliable to use.

Background technique

In order to ensure the safety of railway track structures, it is necessary to conduct regular inspections of track structures. Among the many inspection items, rail vibration testing is a relatively important inspection link. Rail vibration testing is used to obtain the modal parameters of the rails, such as frequency, vibration mode, damping ratio, etc. Since the modal parameters can reflect the dynamic characteristics of the structure itself, the service status of the rails is often judged by modal parameters.

At present, the commonly used rail modal experimental excitation test methods mainly include: manual force hammer excitation and driving excitation, etc. After obtaining the vibration information, the modal parameter identification method is used to obtain the modal parameters that can reflect the structural dynamic characteristics, so as to compare the abnormalities and make maintenance decisions. Manual force hammer excitation is to make the force hammer hit the rail vertically through human operation, and obtain the vibration information of the rail through the sensor installed on the rail in advance; this type of method requires experienced personnel to operate, and the test efficiency is low, which takes up a lot of manpower and time costs. Driving excitation is that the train runs over the test section of the rail, and the sensor is installed on the rail in advance before driving, and the vibration signal is obtained by the sensor during driving; at the same time, in order to ensure the safety of the sensor, the sensor can only be arranged at the waist of the rail, and connected to the rail through a clamp to obtain vibration information; due to the complex transmission path, this method will affect the test accuracy and poor practicality. Therefore, it is necessary to improve the excitation device of the rail modal test in the prior art.

Summary of the invention

The present invention aims at solving the above problems and provides a vehicle-mounted mobile excitation device for rail modal testing, which can realize the change of vertical and lateral excitation direction of the rail, meet the relevant analysis of different direction excitations and different order vibrations of specific rails, quickly detect the corresponding damage of the rails, and has strong practicality and reliability.

The technical solution adopted by the present invention is: the vehicle-mounted mobile excitation device for rail modal testing includes a mobile base, characterized in that: a vehicle-mounted driving mechanism is arranged on the mobile base, the vehicle-mounted driving mechanism includes walking rollers arranged on both sides of the mobile base, the walking rollers are rotatably connected with the mobile base through roller shafts, and a shaft driving gear is arranged on the roller shaft, and the shaft driving gear is connected to the output shaft of the walking drive motor; base lifting mechanisms are respectively arranged on both sides of the front end and the rear end of the mobile base; and flipping excitation mechanisms are symmetrically arranged on both sides of the middle part of the mobile base, and a hydraulic pump station and an exciter air supply system are also arranged on the mobile base.

The mobile base includes a bearing frame, and the four corners of the bearing frame are respectively provided with a lifting mechanism mounting part, and the two sides of the bearing frame are respectively provided with a shaft mounting hole; the two sides of the middle part of the bearing frame are also respectively provided with a flip avoidance notch, and the two sides of the flip avoidance notch are respectively provided with a flip limit plate. The roller shaft of the vehicle-mounted driving mechanism is installed in the shaft mounting hole of the bearing frame, and each base lifting mechanism is respectively arranged at the lifting mechanism mounting part at the four corners of the bearing frame; and the flip limit plate provided at the flip avoidance notch is used to limit the flip position of the flip excitation mechanism.

The base lifting mechanism includes a vertically arranged lifting leg, and the upper end and the middle part of the lifting leg are respectively provided with a horizontally arranged lifting connecting rod, one end of the two lifting connecting rods are respectively hinged to the upper end and the middle part of the lifting leg, and the other end of the lifting connecting rod is respectively hinged to the connecting rod hinge ear plate correspondingly arranged on the side of the mobile base, thereby forming a four-bar linkage; and a lifting hydraulic cylinder is also arranged between the mobile base and the lifting leg, the fixed end of the lifting hydraulic cylinder is hinged to the lifting cylinder hinge ear plate arranged on the side of the mobile base, and the telescopic end of the lifting hydraulic cylinder is hinged to the hinge shaft at the upper end of the lifting leg. The telescopic movement of the lifting hydraulic cylinder is used to drive the four-bar linkage composed of the two lifting connecting rods and the lifting leg to swing back and forth, thereby realizing the swing-down support and the swing-up retraction of the lifting leg.

The lifting leg comprises a leg body, the upper end and the middle part of which are respectively provided with connecting rod hinge holes; the lower end of the leg body is also provided with a support plate hinge part, and the support plate hinge part is hingedly provided with a ground support plate. The lifting leg is hingedly connected to the ends of the two lifting connecting rods through the connecting rod hinge holes respectively provided at the upper end and the middle part of the leg body, and the ground support plate provided at the lower end of the leg body forms a stable contact with the ground.

The lifting link comprises a link body, one end of which is provided with a leg hinge part, which is hinged to the link hinge hole on the lifting leg; the other end of the link body is provided with a base frame hinge part, which is hinged to the link hinge ear plate on the side of the mobile base. By using two lifting links that are arranged in the transverse direction on the side of the mobile base and are respectively hinged to the upper end and the middle part of the lifting leg, a four-bar linkage mechanism that can swing back and forth is formed, so that in the process of performing modal excitation test on the test rail, it is convenient for the base lifting mechanism to lift the mobile base.

The end of the connecting rod body where the leg hinge is arranged is narrow, and the other end of the connecting rod body where the base frame hinge is arranged is wide. The structural strength of the lifting connecting rod is increased by the trapezoidal structure in which one end of the connecting rod body is wide and the other end is narrow, thereby ensuring the support stability of the base lifting mechanism.

The flipping vibration excitation mechanism includes a flipping plate arranged on a bearing plate, one end of the flipping plate is rotatably connected to a flipping plate hinged portion arranged at a flipping opening, and a flipping hydraulic cylinder is arranged between the upper side of the flipping plate and the middle part of the bearing plate, one end of the flipping hydraulic cylinder is hinged to the flipping plate, and the other end of the flipping hydraulic cylinder is hinged to a flipping cylinder hinged ear plate in the middle part of the bearing plate; and a pneumatic vibrator is also arranged on the lower side of the flipping plate. The flipping hydraulic cylinder is used to drive the flipping plate to flip up and down around the flipping plate hinged portion by the extension and contraction of the flipping hydraulic cylinder, thereby changing the posture of the pneumatic vibrator arranged on the lower side of the flipping plate, thereby realizing the change of the vertical and lateral excitation direction of the test rail.

The pneumatic exciter is arranged at the lower end of the connecting vertical arm, and the upper end of the connecting vertical arm is slidably connected to the vertical arm slide rail; and the vertical arm slide rail is fixedly connected to the flap slider, and the flap slider is slidably arranged on the flap slider rail at the lower side of the flip plate; the flap slider rail and the vertical arm slide rail are arranged perpendicular to each other; the flap slider and the connecting vertical arm are respectively provided with a slider locking mechanism for locking the sliding position. The excitation position of the pneumatic exciter arranged at the lower end of the connecting vertical arm can be flexibly adjusted by the free sliding of the flap slider and the connecting vertical arm on the flap slider rail and the vertical arm slide rail arranged perpendicular to each other, so as to facilitate the use of the device.

The connecting arm is in an L-shaped shape, wherein one section is bent and slidably connected to the arm slide rail, and the other section is bent and connected to the pneumatic vibrator at the end thereof, so that the pneumatic vibrator arranged at the end of the connecting arm can fully adapt to different vertical or horizontal working conditions when the flip plate flips.

The ends of the flap slide rail and the vertical arm slide rail are respectively provided with limit blocks to limit the positions of the flap slider and the connecting vertical arm on the flap slide rail and the vertical arm slide rail to prevent them from sliding out of the track.

The beneficial effects of the present invention are as follows: since the present invention adopts a mobile base on which a vehicle-mounted driving mechanism is arranged, the vehicle-mounted driving mechanism includes travel rollers arranged on both sides of the mobile base, the travel rollers are rotatably connected to the mobile base through roller shafts, a shaft driving gear is arranged on the roller shaft, and the shaft driving gear is connected to the output shaft of the travel driving motor; both sides of the front end and the rear end of the mobile base are respectively provided with a base lifting mechanism; both sides of the middle part of the mobile base are symmetrically provided with a flipping excitation mechanism, and a hydraulic pump station and an exciter air supply system are arranged on the mobile base, so the present invention has a reasonable design and a compact structure, can realize the change of the vertical and lateral excitation direction of the rails, can meet the relevant analysis of different direction excitations and different order vibrations of specific rails, quickly detect the corresponding damage of the rails, has strong practicality, and is reliable to use. The test object of this vehicle-mounted mobile excitation device is a steel rail of a specific rail type. By providing swept frequency vibration, it can be known that the amplitude of the steel rail is the largest at a certain vibration frequency. This vibration frequency is the natural frequency of the steel rail. By comparing the natural frequency detected by vibration with the natural frequency of the standard steel rail, it can be determined whether there is a corresponding fault in a certain section of the steel rail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a structure of the present invention (the flip excitation mechanism is in a vertical excitation working state).

FIG. 2 is a schematic diagram of a lower structure after removing the upper flip vibration excitation mechanism, hydraulic pump station and exciter air supply system from FIG. 1 .

FIG. 3 is a schematic structural diagram of the mobile base in FIG. 2 .

FIG. 4 is a schematic structural diagram of the base lifting mechanism in FIG. 2 .

FIG. 5 is a view taken along the arrow A of FIG. 4 .

FIG. 6 is a schematic structural diagram of the lifting legs in FIG. 4 .

FIG. 7 is a schematic structural diagram of the lifting connecting rod in FIG. 4 .

FIG. 8 is a schematic structural diagram of the flip excitation mechanism in FIG. 1 .

FIG. 9 is a view taken along the arrow B in FIG. 8 .

FIG. 10 is a schematic diagram of an implementation of the flipping excitation mechanism in FIG. 1 in a lateral excitation working state.

FIG. 11 is a flow chart of a control system of the present invention.

FIG. 12 is a curve diagram of the rail modal frequency acceleration amplitude of the present invention.

Explanation of the numbers in the figure: 1 mobile base, 2 vehicle-mounted drive mechanism, 3 base lifting mechanism, 4 flip vibration mechanism, 5 hydraulic pump station, 6 vibration exciter air supply system, 7 test rail, 8 walking roller, 9 roller shaft, 10 shaft driving gear, 11 speed sensor, 12 flip limit plate, 13 load-bearing frame, 14 lifting mechanism installation part, 15 connecting rod hinge ear plate, 16 lifting cylinder hinge ear plate, 17 shaft installation hole, 18 flip avoidance notch, 19 lifting connecting rod, 20 lifting leg, 21 Ground support plate, 22 lifting hydraulic cylinder, 23 support leg body, 24 connecting rod hinge hole, 25 support plate hinge part, 26 connecting rod body, 27 support leg hinge part, 28 base frame hinge part, 29 load-bearing plate, 30 flip opening, 31 flip plate, 32 flip hydraulic cylinder, 33 flip cylinder hinge ear plate, 34 flap slide rail, 35 flap slider, 36 slider locking mechanism, 37 vertical arm slide rail, 38 connecting vertical arm, 39 pneumatic exciter, 40 pneumatic triplet, 41 flap hinge part, 42 limit block.

Detailed ways

The specific structure of the present invention is described in detail with reference to FIGS. 1 to 10 . The vehicle-mounted mobile excitation device for rail modal testing includes a mobile base 1 that can move on a test rail 7, and a vehicle-mounted driving mechanism 2 is provided on the mobile base 1. The vehicle-mounted driving mechanism 2 includes four travel rollers 8 provided on both sides of the mobile base 1, and the two corresponding travel rollers 8 on the left and right are connected by a roller shaft 9, and the roller shaft 9 is rotationally connected to the mobile base 1. At the same time, a shaft driving gear 10 is provided on the roller shaft 9, and the shaft driving gear 10 is connected to the output shaft of the travel driving motor; the travel rollers 8 are respectively rollingly connected to the test rails 7 on the corresponding sides. In order to detect the running speed of the mobile base 1, the shaft driving gear 10 on the roller shaft 9 is also meshed with the speed measuring gear at the input end of the speed sensor 11.

The mobile base 1 is composed of a bearing frame 13, which is an integrated structure formed by bending a steel section, and a bearing plate 29 for arranging the overturning vibration mechanism 4, the hydraulic pump station 5 and the exciter air supply system 6 is arranged on the upper side of the bearing frame 13. The four corners of the square bearing frame 13 are respectively provided with a lifting mechanism installation part 14 for arranging the base lifting mechanism 3, and the two sides of the bearing frame 13 are respectively provided with a shaft installation hole 17. The two sides of the middle part of the bearing frame 13, where the overturning vibration mechanism 4 is arranged, are also respectively provided with a overturning avoidance notch 18; and the two sides of the overturning avoidance notch 18 are respectively provided with a overturning limit plate 12. Thus, the roller shaft 9 of the vehicle-mounted drive mechanism 2 is installed in the shaft installation hole 17 of the bearing frame 13, and each base lifting mechanism 3 is respectively arranged at the lifting mechanism installation part 14 at the four corners of the bearing frame 13; and the overturning position of the overturning vibration mechanism 4 is limited by the overturning limit plate 12 arranged at the overturning avoidance notch 18.

Four base lifting mechanisms 3 are respectively arranged on both sides of the front and rear ends of the mobile base 1. The base lifting mechanism 3 includes a vertically arranged lifting leg 20, and the upper end and the middle part of the lifting leg 20 are respectively provided with a transversely arranged lifting link 19, one end of the two lifting links 19 is respectively hinged to the upper end and the middle part of the lifting leg 20, and the other end of the lifting link 19 is respectively hinged to the link hinge ear plate 15 correspondingly arranged on the side of the mobile base 1, thereby forming a four-bar linkage. At the same time, a lifting hydraulic cylinder 22 is also arranged between the mobile base 1 and the lifting leg 20, the fixed end of the lifting hydraulic cylinder 22 is hinged to the lifting cylinder hinge ear plate 16 arranged on the side of the mobile base 1, and the telescopic end of the lifting hydraulic cylinder 22 is hinged to the hinge shaft at the upper end of the lifting leg 20; each lifting hydraulic cylinder 22 is connected to the hydraulic pump station 5 arranged on the mobile base 1 through a hydraulic pipeline. The extension and retraction of the lifting hydraulic cylinder 22 is then used to drive the four-bar linkage composed of two lifting links 19 and the lifting legs 20 to swing back and forth, so as to achieve the downward swing support (the moving base 1 rises, and the walking roller 8 leaves the test rail 7) or the upward swing retraction (the moving base 1 descends, and the walking roller 8 contacts the test rail 7) of the lifting legs 20.

The lifting leg 20 of the base lifting mechanism 3 is composed of a leg body 23, and the upper end and the middle part of the leg body 23 are respectively provided with connecting rod hinge holes 24; the lower end of the leg body 23 is also provided with a support plate hinge part 25, and the support plate hinge part 25 is hingedly provided with a ground support plate 21, so that the lifting leg 20 is hinged to the end parts of the two lifting connecting rods 19 through the connecting rod hinge holes 24 respectively provided at the upper end and the middle part of the leg body 23, and the ground support plate 21 provided at the lower end of the leg body 23 is used to form a stable contact with the ground.

The lifting link 19 of the base lifting mechanism 3 is composed of a link body 26, one end of which is provided with a leg hinge part 27, and the lifting link 19 is hinged to the link hinge hole 24 at the upper end or the middle part of the lifting leg 20 through the leg hinge part 27. The other end of the link body 26 is provided with a base frame hinge part 28, and the lifting link 19 is hinged to the link hinge ear plate 15 at the side of the mobile base 1 through the base frame hinge part 28; and then, two lifting links 19 are arranged in the transverse direction on the side of the mobile base 1 and are respectively hinged to the upper end and the middle part of the lifting leg 20 to form a reciprocating four-bar linkage mechanism, so as to facilitate the lifting of the mobile base 1 by the base lifting mechanism 3 during the modal excitation test of the test rail 7. The lifting link 19 has a narrower structure at one end of the link body 26 where the leg hinge 27 is provided, while the other end of the link body 26 where the base frame hinge 28 is provided is wider; thereby, the structural strength of the lifting link 19 is increased by the trapezoidal structure in which one end of the link body 26 is wide and the other end is narrow, thereby ensuring the supporting stability of the base lifting mechanism 3.

A flipping vibration mechanism 4 is symmetrically arranged on both sides of the middle part of the mobile base 1, and the flipping vibration mechanism 4 includes a flip plate 31 arranged on the upper side supporting plate 29 of the mobile base 1, and one end of the flip plate 31 is rotatably connected to a flip plate hinge part 41 arranged at the flip opening 30 on the supporting plate 29; and two groups of flipping hydraulic cylinders 32 are arranged between the upper side of the flip plate 31 and the middle part of the supporting plate 29, one end of the flipping hydraulic cylinder 32 is hinged to the flip plate 31, and the other end of the flipping hydraulic cylinder 32 is hinged to the flip cylinder hinge ear plate 33 in the middle part of the supporting plate 29; each flipping hydraulic cylinder 32 is connected to a hydraulic pump station 5 arranged on the mobile base 1 through a hydraulic pipeline. In addition, a pneumatic vibrator 39 (for example, FP-12-M pneumatic vibrator) is also provided on the lower side of the flip plate 31, so as to utilize the extension and retraction of the flip hydraulic cylinder 32 to drive the flip plate 31 to flip up and down around the flip plate hinge 41 (from vertical to horizontal 90° flip), thereby changing the posture of the pneumatic vibrator 39 provided on the lower side of the flip plate 31, thereby satisfying the conversion of vertical and lateral excitation of the pneumatic vibrator 39, and realizing the change of the vertical and lateral excitation direction of the test rail 7.

The pneumatic exciter 39 is arranged at the lower end of the connecting arm 38. The connecting arm 38 is L-shaped, wherein a section of the upper end is bent and slidably connected to the arm slide rail 37, and the end of the other section of the lower end is connected to the pneumatic exciter 39 through a flange. The air supply pipeline of the pneumatic exciter 39 is connected to the exciter air supply system 6 arranged on the mobile base 1 through the pneumatic triplet 40; thereby, the pneumatic exciter 39 arranged at the end of the L-shaped connecting arm 38 can fully adapt to different vertical or horizontal working conditions with the flipping plate 31. In addition, the arm slide rail 37 is fixedly connected to the flip slide 35, and the flip slide 35 is slidably arranged on the flip slide 34 on the lower side of the flip plate 31. The flip slide 34 and the arm slide rail 37 are arranged perpendicular to each other; the flip slide 35 and the connecting arm 38 are respectively provided with a slide locking mechanism 36 for locking the sliding position on the flip slide 34 and the arm slide 37 (as shown in Figures 8 and 9). Furthermore, the excitation position of the pneumatic vibrator 39 at the lower end of the connecting arm 38 can be flexibly adjusted by the free sliding of the flap slider 35 and the connecting arm 38 on the flap slide rail 34 and the connecting arm slide rail 37 arranged perpendicular to each other, so as to facilitate the use of the device. The ends of the flap slide rail 34 and the connecting arm slide rail 37 are respectively provided with limit blocks 42 to limit the positions of the flap slider 35 and the connecting arm 38 on the flap slide rail 34 and the connecting arm slide rail 37 to prevent them from sliding off the track and ensure the reliability of the device.

When the vehicle-mounted mobile excitation device for rail modal testing is used, first, the travel drive motor is turned on to drive the vehicle-mounted drive mechanism 2 to drive the mobile base 1 to move forward along the test rail 7 at a constant speed for a fixed distance (for example: 100 meters) and then stop; at this time, the lifting legs 20 of the four base lifting mechanisms 3 are all in the initial state of upward swinging and retracting (the travel rollers 8 are in rolling contact with the test rail 7), and the two flip excitation mechanisms 4 are in the initial posture of vertical excitation (as shown in Figure 1). After the mobile base 1 stops steadily, the lifting hydraulic cylinder 22 of the base lifting mechanism 3 is extended, and then the lifting legs 20 are driven to swing down through the four-bar mechanism composed of two lifting links 19 and the lifting legs 20 to support, and the mobile base 1 is lifted upward (the travel rollers 8 and the test rail 7 are separated from each other to avoid affecting the excitation test). Then, the vertical excitation position of the pneumatic vibrator 39 is adjusted by freely sliding the flap slider 35 and the connecting arm 38 on the flap slide rail 34 and the arm slide rail 37 respectively, so that the vibrator contacts the outer surface of the rail and the slider locking mechanism 36 is locked; thereafter, the pneumatic vibrator 39 is turned on, and force is applied at a certain frequency to perform a vertical excitation test on the test rail 7 (the position where it stays).

After finishing the vertical excitation test of the test rail 7 at this position, adjust the position of the flap slider 35 and the connecting arm 38 to increase the vertical and lateral distance between the pneumatic vibrator 39 and the rail, which is beneficial for the subsequent flipping and changing direction. Then, use the flip hydraulic cylinder 32 to drive the flip plate 31 of the flip vibration mechanism 4 to flip downward around the flap hinge 41 (from vertical to horizontal, 90° flip), so as to change the pneumatic vibrator 39 on the lower side of the flip plate 31 to a lateral excitation posture (as shown in Figure 10). Use the flap slider 35 and the connecting arm 38 again to adjust the lateral excitation position of the pneumatic vibrator 39 and lock it, turn on the pneumatic vibrator 39, apply force at a certain frequency, and perform a lateral excitation test on the test rail 7. When the lateral excitation test of the test rail 7 at this position is also completed, the lifting legs 20 of the four base lifting mechanisms 3 are swung up and retracted to the initial state, so that the walking rollers 8 are in contact with the test rail 7, and the two flipping vibration mechanisms 4 are also flipped upward back to the initial posture of vertical excitation; thereby preparing for the next operation cycle of moving the mobile base 1 forward, supporting the base lifting mechanism 3, and exciting the flipping vibration mechanism 4.

By exciting the test rail and analyzing the data collected from multiple acquisition points, the frequency acceleration amplitude curve of the test rail can be obtained (as shown in Figure 12). The frequency corresponding to the peak of the curve is the natural frequency of the test rail. Then, by comparing the natural frequency detected by vibration with the natural frequency of the standard rail, it can be determined whether there is a fault in a certain section of the test rail. The vehicle-mounted mobile excitation device can realize the simultaneous excitation of two rails, and can automatically switch the vertical and lateral excitation forces and sweep the vibration frequency, which can conveniently realize the rail modal test.

Claims (8)

1. A vehicle-mounted mobile excitation device for rail modal testing, comprising a mobile base (1), characterized in that: the mobile base (1) is provided with a vehicle-mounted drive mechanism (2), the vehicle-mounted drive mechanism (2) comprises travel rollers (8) arranged on both sides of the mobile base (1), the travel rollers (8) are rotatably connected to the mobile base (1) via roller shafts (9), and the roller shafts (9) are provided with shaft drive gears (10), and the shaft drive gears (10) are connected to the output shaft of the travel drive motor; both sides of the front end and the rear end of the mobile base (1) are respectively provided with base lifting mechanisms (3); and the mobile base ( 1) The two sides of the middle part are symmetrically provided with a flipping vibration mechanism (4), and the mobile base (1) is also provided with a hydraulic pump station (5) and a vibration exciter air supply system (6); the base lifting mechanism (3) includes a vertically arranged lifting leg (20), and the upper end and the middle part of the lifting leg (20) are respectively provided with a transversely arranged lifting connecting rod (19), one end of the two lifting connecting rods (19) are respectively hinged to the upper end and the middle part of the lifting leg (20), and the other end of the lifting connecting rod (19) is respectively hinged to the connecting rod hinge ear plate (15) correspondingly provided on the side of the mobile base (1), thereby forming a four-bar linkage; and the mobile base (1) and the lifting A lifting hydraulic cylinder (22) is also provided between the lifting legs (20), the fixed end of the lifting hydraulic cylinder (22) is hinged to a lifting cylinder hinged ear plate (16) provided on the side of the movable base (1), and the telescopic end of the lifting hydraulic cylinder (22) is hinged to a hinged rotating shaft at the upper end of the lifting legs (20); the flipping excitation mechanism (4) comprises a flipping plate (31) provided on the bearing plate (29), one end of the flipping plate (31) is rotatably connected to a flipping plate hinge portion (41) provided at the flipping opening (30), and a flipping hydraulic cylinder (32) is provided between the upper side of the flipping plate (31) and the middle part of the bearing plate (29), and the flipping hydraulic cylinder (32) One end of the flip plate (31) is hingedly connected to the flip plate (31), and the other end of the flip hydraulic cylinder (32) is hingedly connected to the flip cylinder hinge ear plate (33) in the middle of the load-bearing plate (29); and a pneumatic vibrator (39) is also arranged on the lower side of the flip plate (31); the flip hydraulic cylinder (32) is used to drive the flip plate (31) to flip up and down around the flip plate hinge part (41), that is, to flip from vertical to horizontal by 90 degrees, thereby changing the posture of the pneumatic vibrator (39) arranged on the lower side of the flip plate (31), thereby satisfying the conversion of vertical and horizontal excitation of the pneumatic vibrator (39), and realizing the change of the vertical and horizontal excitation direction of the test rail (7). 2. The vehicle-mounted mobile excitation device for rail modal testing according to claim 1 is characterized in that: the mobile base (1) includes a supporting frame (13), and the four corners of the supporting frame (13) are respectively provided with lifting mechanism mounting parts (14), and the two sides of the supporting frame (13) are respectively provided with shaft mounting holes (17); the two sides of the middle part of the supporting frame (13) are also respectively provided with flip avoidance notches (18), and the two sides of the flip avoidance notches (18) are respectively provided with flip limit plates (12). 3. The vehicle-mounted mobile excitation device for rail modal testing according to claim 1 is characterized in that: the lifting leg (20) includes a leg body (23), and the upper end and the middle part of the leg body (23) are respectively provided with connecting rod hinge holes (24); the lower end of the leg body (23) is also provided with a support plate hinge part (25), and the support plate hinge part (25) is hingedly provided with a ground support plate (21). 4. The vehicle-mounted mobile excitation device for rail modal testing according to claim 3 is characterized in that: the lifting connecting rod (19) includes a connecting rod body (26), one end of the connecting rod body (26) is provided with a leg hinge part (27), and the leg hinge part (27) is hinged to the connecting rod hinge hole (24) on the lifting leg (20); the other end of the connecting rod body (26) is provided with a base frame hinge part (28), and the base frame hinge part (28) is hinged to the connecting rod hinge ear plate (15) on the side of the mobile base (1). 5. The vehicle-mounted mobile excitation device for rail modal testing according to claim 4 is characterized in that one end of the connecting rod body (26) where the leg hinge part (27) is provided is narrow, and the other end of the connecting rod body (26) where the base frame hinge part (28) is provided is wide. 6. The vehicle-mounted mobile excitation device for rail modal testing according to claim 1 is characterized in that: the pneumatic exciter (39) is arranged at the lower end of the connecting arm (38), and the upper end of the connecting arm (38) is slidably connected to the arm slide rail (37); and the arm slide rail (37) is fixedly connected to the flap slider (35), and the flap slider (35) is slidably arranged on the flap slider (34) on the lower side of the flip plate (31); the flap slider (34) and the arm slide rail (37) are arranged perpendicular to each other; and the flap slider (35) and the connecting arm (38) are respectively provided with a slider locking mechanism (36) for locking the sliding position. 7. The vehicle-mounted mobile excitation device for rail modal testing according to claim 6 is characterized in that the connecting arm (38) is L-shaped, one section of which is bent and slidably connected to the arm slide rail (37), and the end of the other section of the bend is connected to the pneumatic exciter (39). 8. The vehicle-mounted mobile excitation device for rail modal testing according to claim 6 is characterized in that: limit blocks (42) are respectively provided at the ends of the flap slide rail (34) and the vertical arm slide rail (37).