A vehicle body excitation device and a vehicle excitation method

Abstract

The application provides a vehicle body excitation device, which comprises a mounting base, a power mechanism, a transmission assembly and a docking assembly; the power mechanism comprises a mounting frame fixedly connected with the base and an exciter connected with the mounting frame; the transmission assembly comprises a transmission force arm and a hinged seat fixedly connected with the base; a hinged base is formed in the middle of the transmission force arm and is connected with the hinged seat and limited in the y direction; the hinged base is connected with a first force arm extending in the direction of the exciter and a second force arm extending in the x direction; the first force arm is in transmission connection with the exciter; the docking assembly comprises a connecting base block fixedly connected with the second force arm and a docking end head fixedly connected with the connecting base block and arranged in the z direction. The application conducts excitation force transmission through the lever principle, the transmission structure is relatively simple, compared with the hydraulic excitation module of the prior art, the application can generate less interference noise, the abnormal sound detection result is more accurate, and the upper limit of the excitation frequency is higher.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle abnormal sound detection, in particular to a vehicle body excitation device and a whole vehicle excitation method. BACKGROUND

[0002] Abnormal sound refers to Buzz, Squeak & Rattle and other non-steady-state noises generated by road excitation of a vehicle. Such annoying abnormal sound in the vehicle often means quality problems of the whole vehicle or parts. Investigation and research have found that a large number of complaints from vehicle owners come from abnormal sound caused by the vehicle body and interior decoration. Therefore, vehicle manufacturers usually conduct whole vehicle abnormal sound tests to maximize the discovery, analysis and judgment of the root cause of abnormal sound and eliminate such non-steady-state noises to improve product quality and customer satisfaction.

[0003] In the prior art, whole vehicle abnormal sound tests are generally carried out on a four-channel vehicle test bench. The four-channel whole vehicle test bench has four hydraulic excitation modules that can vibrate up and down. During the test, each hydraulic excitation module supports one wheel, and the corresponding road simulation parameters are input to the hydraulic excitation module to perform the whole vehicle abnormal sound test. The structure of the hydraulic excitation module of this test method is relatively complex, the cost is relatively high, and the four hydraulic support modules bear the full weight of the vehicle. The test process has relatively large interference noise, which easily covers some relatively weak abnormal sound. SUMMARY

[0004] To solve the above problems, the present application discloses a vehicle body excitation device and a whole vehicle abnormal sound test bench. The structure of the vehicle body excitation device and its auxiliary system is more simple, the cost is lower and the operability is better compared with the existing hydraulic excitation module, and the interference noise is smaller during operation, which has less influence on abnormal sound analysis.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] A vehicle body excitation device, comprising a mounting base, a power mechanism, a transmission assembly and a docking assembly; the power mechanism comprises a mounting bracket fixedly connected with the base and an exciter connected with the mounting bracket; the transmission assembly comprises a transmission arm and a hinge seat, the hinge seat is fixedly connected with the base, a hinge base is formed in the middle of the transmission arm and is connected with the hinge seat and limited in the y direction, the hinge base is connected with a first arm extending in the direction of the exciter and a second arm extending in the x direction, the first arm is in transmission connection with the exciter; the docking assembly comprises a connecting base block fixedly connected with the second arm and a docking end head fixedly connected with the connecting base block and arranged in the z direction.

[0007] Further, the vehicle body excitation device further comprises an elastic limiting piece, the elastic limiting piece comprises an elastic sheet and a first positioning part and a second positioning part arranged at two ends of the elastic sheet, the first positioning part and the second positioning part are fixedly connected with the base and the connecting base block respectively and the elastic sheet is arranged perpendicularly to the z direction.

[0008] Further, the elastic limiting piece comprises a first elastic sheet and a second elastic sheet arranged in parallel and in the z direction, the first ends of the first elastic sheet and the second elastic sheet are integrally connected through a first positioning part, the second ends of the first elastic sheet and the second elastic sheet are respectively provided with a second connecting part, and the mounting base is provided with a first matching part corresponding to the first elastic sheet and a second matching part corresponding to the second elastic sheet.

[0009] Further, the length of the first force arm is greater than that of the second force arm.

[0010] Further, the hinged seat comprises an elastic hinged sheet and a first end block and a second end block fixedly arranged at two ends of the elastic hinged sheet respectively, the first end block and the second end block are fixedly connected with the mounting base and the connecting base block respectively, and the elastic hinged sheet comprises a first hinged sheet and a second hinged sheet arranged in parallel and perpendicularly to the y direction.

[0011] Further, the intersection line of the plane where the first hinged sheet is arranged and the plane where the second hinged sheet is arranged is recorded as a hinged axis, and the first hinged sheet is overlapped with the second hinged sheet after rotating 90° around the hinged axis.

[0012] Further, the docking assembly comprises a mounting guide rod extending in the z direction, an adjusting frame and a locking piece, the connecting base block is provided with a guide hole arranged in the z direction and matched with the lower end of the mounting guide rod, the adjusting frame is sleeved with the upper end of the mounting guide rod, and the locking piece is fixedly connected with the outer periphery of the mounting guide rod.

[0013] Further, the adjusting frame comprises an upper base plate, a lower base plate and a support plate, the upper base plate and the lower base plate are arranged in parallel, the two ends of the support plate are perpendicularly connected with the edge of the upper base plate and the edge of the lower base plate respectively, the lower base plate is provided with an adjusting hole through which the mounting guide rod passes, and the docking end head is fixedly connected with the upper base plate.

[0014] Further, the vehicle body excitation device further comprises an air bag assembly, the air bag assembly comprises a mounting outer frame and a first air bag and a second air bag arranged inside the mounting outer frame, the end of the first force arm is connected with an extension part, and the first air bag and the second air bag are respectively abutted with two sides of the movement direction of the extension part.

[0015] The application further provides a whole vehicle excitation method based on the above-mentioned vehicle body excitation device, comprising the following steps:

[0016] a. Provide a base having a horizontal mounting surface on its upper side, on which a number of wheel alignment platforms corresponding to the number of wheels of the vehicle to be tested are fixed according to the structure of the vehicle to be tested, and wherein the upper ends of the wheel alignment platforms have a curved table surface for placing wheels;

[0017] b. fixing at least one excitation group on the horizontal mounting surface, each excitation group comprising two vehicle body excitation devices symmetrically arranged about the longitudinal centerline of the wheel alignment stand;

[0018] c. Place each wheel of the vehicle to be tested on the corresponding wheel alignment platform;

[0019] d. A process hole facing downward in the z-direction is provided at the bottom of the sill beam of the vehicle to be tested. The docking end of the vehicle body excitation device is adjusted so that the process hole of the docking end is aligned in the z-direction and fixedly connected;

[0020] e. Start the vehicle body excitation device to apply synchronous z-axis excitation to the vehicle to be tested, thereby achieving whole vehicle excitation.

[0021] The application of the present invention can achieve the following beneficial effects:

[0022] 1. The present invention drives the butt joint end of the transmission arm to vibrate in the z-direction through the exciter, so that the vehicle body structure connected to the butt joint end is vibrated in the z-direction. During the vehicle body excitation process, the vehicle is placed on the wheel alignment platform, and its main weight is borne by the wheel alignment platform. The butt joint end only needs to provide the corresponding excitation force and does not need to bear the weight of the entire vehicle like the hydraulic excitation module in the prior art. Therefore, the thrust requirement for the exciter is lower, which reduces the equipment cost. At the same time, it can also provide a higher excitation frequency to achieve more comprehensive abnormal noise detection.

[0023] 2. The present invention conducts exciting force through the lever principle, and the transmission structure is relatively simple. Compared with the hydraulic excitation module in the prior art, it can generate less interference noise, and the abnormal noise detection result is more accurate.

[0024] 3. Some embodiments of the present invention further use elastic limiting members to limit the docking assembly, so that the docking assembly can vibrate along the z-direction as much as possible, reducing interference caused by vibration errors and ensuring the accuracy of the test results.

[0025] 4. Some embodiments of the present invention are provided with mounting guide rods and adjustment frames to change the height position of the docking end, which can quickly dock the docking end with the process hole on the bottom of the vehicle body, and the z-direction orientation of the docking end will not be changed during the adjustment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the structure of the vehicle body vibration excitation device in the embodiment;

[0027] Figure 2 is a structural schematic view of a transmission assembly;

[0028] Figure 3 is a structural schematic view of a docking assembly;

[0029] Figure 4 is a structural schematic view of an elastic limiting piece;

[0030] Figure 5 is a structural schematic view of a whole vehicle abnormal sound test bench;

[0031] In the figure, 1 is a mounting base, 2 is a power mechanism, 21 is a mounting frame, 22 is a vibration exciter, 3 is a transmission assembly, 31 is a transmission force arm, 311 is a hinged base, 312 is a first force arm, 313 is a second force arm, 314 is an extension, 32 is a hinged seat, 321 is a first end block, 322 is a second end block, 323 is a first hinged piece, 324 is a second hinged piece, 4 is a docking assembly, 41 is a connecting base block, 411 is a first matching part, 412 is a second matching part, 413 is a guide hole, 42 is a docking end, 43 is a mounting guide rod, 44 is an adjusting frame, 441 is an upper base plate, 442 is a lower base plate, 4221 is an adjusting hole, 443 is a support plate, 45 is a locking piece, 5 is an elastic limiting piece, 6 is an air bag assembly, 7 is a base, 8 is a wheel alignment bench, 81 is an arc-shaped bench surface, a1 is a first vehicle body excitation device, and a2 is a second vehicle body excitation device. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be described clearly and completely below in conjunction with embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. EMBODIMENT

[0033] Reference Figures 1-4 The embodiments of the first aspect of the present application provide a vehicle body excitation device, which comprises a mounting base 1, a power mechanism 2, a transmission assembly 3 and a docking assembly 4, and specifically:

[0034] The mounting base 1 has a plurality of mounting sites for providing an assembly basis for other mechanisms;

[0035] The power mechanism 2 comprises a mounting frame 21 and a vibration exciter 22, the mounting frame is fixedly connected with the mounting base, and the vibration exciter is connected with the mounting frame and has its output end z downwardly arranged for outputting a vibration excitation force;

[0036] The transmission assembly 3 comprises a transmission force arm 31 and a hinged seat 32; a hinged base 311 is formed in the middle of the transmission force arm and is connected with the hinged seat and is limited in the y direction, under the guidance and limitation of the hinged seat, the hinged base cannot move in the y direction, but can only rotate in the x-z plane, the hinged base is connected with a first force arm 312 extending to the first side in the x direction and a second force arm 313 extending to the second side in the x direction, the first force arm gradually approaches the exciter in the extension direction, and is fixedly connected with the output end of the exciter, so that the output end can drive the end of the first force arm to vibrate in the z direction, and then under the guidance and limitation of the hinged seat, the whole transmission force arm is transmitted in the x-z plane, at this time, the end of the second force arm will vibrate in the z direction in the opposite direction of the end of the first force arm; generally, the length of the first force arm is greater than that of the second force arm, on the one hand, the thrust output by the exciter is amplified when acting on the vehicle by using the lever principle, thereby reducing the equipment requirement, on the other hand, the amplitude of the vehicle is reduced in a certain proportion relative to the exciter, and when the amplitude of the exciter is adjusted, the amplitude of the vehicle changes relatively small, so that the amplitude of the vehicle can be finely adjusted.

[0037] The docking assembly 4 comprises a connecting base block 41 and a docking end 42, the connecting base block is fixedly connected with the end of the second force arm, so that the second force arm can drive the connecting base block to vibrate in the z direction, the docking end is fixed on the upper side of the connecting base block, and the axis of the docking end is arranged in the z direction, so that the vehicle body structure connected with the docking end can be subjected to the z direction excitation force, and the vehicle body excitation is realized.

[0038] An embodiment of the present application also provides a specific structure of the hinged seat 32, in the embodiment, the hinged seat comprises an elastic hinged sheet in the middle, the two ends of the elastic hinged sheet are fixedly connected with a first end block 321 and a second end block 322 respectively, the first end block and the second end block are fixedly connected with the mounting base 1 and the hinged base 311 respectively, the elastic hinged sheet comprises a first hinged sheet 323 and a second hinged sheet 324 arranged perpendicularly to each other, the intersection line of the plane where the first hinged sheet is located and the plane where the second hinged sheet is located is marked as a hinged axis, the first hinged sheet can coincide with the second hinged sheet after rotating 90° around the hinged axis, and the first hinged sheet and the second hinged sheet are connected with the hinged base 311 and the mounting base 1 respectively. Figure 2In the embodiment, the first hinged piece is arranged perpendicularly to the x direction, the second hinged piece is arranged perpendicularly to the z direction, the first end block and the second end block are respectively provided with a first recess and a second recess for mounting the elastic hinged pieces, the first recess has a first corresponding surface perpendicularly to the x direction and a first corresponding surface perpendicularly to the z direction, the second recess has a third corresponding surface perpendicularly to the x direction and a fourth corresponding surface perpendicularly to the z direction, the two ends of the first hinged piece are respectively in contact with the first corresponding surface and the third corresponding surface and are fixed by screws, the two ends of the second hinged piece are respectively in contact with the second corresponding surface and the fourth corresponding surface and are fixed by screws, due to the structural features of the first hinged piece and the second hinged piece, the z direction translation and the x direction translation of the second end block 322 are respectively limited by the first hinged piece and the second hinged piece, and the y direction translation is simultaneously limited by the first hinged piece and the second hinged piece, but when the second end block rotates around the hinged axis, the first hinged piece and the second hinged piece can be twisted to a certain extent, so that when the first force arm is driven by the exciter, the hinged base can rotate around the hinged axis; in a more specific embodiment, the first hinged piece or the second hinged piece is formed by stacking a plurality of elastic metal pieces, so that the first hinged piece or the second hinged piece has a certain rigidity to resist the translation of the second end block, while retaining a certain elasticity to cooperate with the rotation of the second end block.

[0039] One embodiment of the present application also provides a specific structure of the docking assembly 4, referring to Figure 3In the embodiment, the docking assembly 4 further comprises a mounting guide rod 43, an adjusting frame 44 and a locking member 45. The upper side of the connecting base block 41 is provided with a z-direction through guide hole 413. The mounting guide rod is matched with the guide hole in the z-direction, and is relatively fixed with the connecting base block by a locking member 45 which is sleeved on the outer periphery of the mounting guide rod. The adjusting frame is matched with the mounting guide rod in a sleeved manner and can move up and down along the mounting guide rod. Another locking member relatively fixes the adjusting frame and the mounting guide rod. The docking end head 42 is arranged at the upper end of the adjusting frame. When necessary, the corresponding locking member can be loosened, so that the adjusting frame can slide in the z-direction along the mounting guide rod. After sliding to a suitable position, the locking member is used for fixing, so that the height adjustment of the docking end head can be realized. In a further embodiment, the adjusting frame comprises an upper base plate 441, a lower base plate 442 and two support plates 443. The upper base plate and the lower base plate are arranged in parallel to the x-y plane. The upper end and the lower end of the support plate are respectively and perpendicularly connected with the side edges of the upper base plate and the lower base plate. The two support plates are parallel to each other and are located on the two sides. A plurality of hollow holes are arranged on the support plate. The lower base plate is provided with a through adjusting hole 4221. The docking end head 42 is fixedly connected with the upper side of the upper base plate. A certain space is left between the upper base plate and the lower base plate to allow the relative movement of the mounting guide rod. The above structure makes the adjusting frame itself have a certain deformation elasticity to adapt to various stress changes in the z-direction vibration process through the support plate.

[0040] In an embodiment of the present application, the vehicle body vibration excitation device further comprises an elastic limiting member 5, which is fixedly connected with the mounting base 1 and the connecting base block 41. Figure 1 and Figure 4 In the embodiment, the elastic limiting member 5 comprises a spring sheet 51 and first and second positioning portions 52 and 53 arranged at the two ends of the spring sheet. The first positioning portion is used for fixedly connecting with the mounting base 1, and the second positioning portion is used for fixedly connecting with the connecting base block 41. In the connected state, the spring sheet is arranged perpendicularly to the z-direction, so that the spring sheet can bend and vibrate in the z-direction, but cannot bend and vibrate in the x-direction or the y-direction, thereby playing a limiting and guiding role to make the docking assembly vibrate in the z-direction as much as possible. In a further embodiment of the present application, the spring sheet comprises a first spring sheet and a second spring sheet arranged in a top-down manner. The first ends of the first spring sheet and the second spring sheet are integrally connected through a first positioning portion. The second ends of the first spring sheet and the second spring sheet are respectively provided with a second connecting portion. The connecting base block has a first matching portion 411 for connecting the first spring sheet and a second matching portion for connecting the second spring sheet.

[0041] In an embodiment of the present application, an entire vehicle excitation method is also provided, which is implemented in cooperation with the entire vehicle abnormal sound test bench shown in Figure 5 . Specifically, the entire vehicle excitation method comprises the following steps:

[0042] a. Provide a base 7 having a horizontal mounting surface on its upper side. Four wheel alignment platforms 8 are fixedly mounted on the horizontal mounting surface according to the structure of the vehicle to be tested. The upper ends of the wheel alignment platforms have curved surfaces 81 for placing wheels. The wheel alignment platforms are detachably fixedly connected to the base, allowing the positions of the wheel alignment platforms to be adjusted to accommodate different vehicle models.

[0043] b. A vibration excitation assembly is fixedly mounted on the horizontal mounting surface, the vibration excitation assembly comprising a first vehicle body excitation device a1 and a second vehicle body excitation device a2 symmetrically arranged about the longitudinal centerline of the wheel alignment stand; the vehicle body excitation devices are detachably fixedly connected to the base via mounting bases, enabling the positions of the docking ends of the vehicle body excitation devices to be adjusted to align with corresponding connection points on the vehicle;

[0044] c. Place the four wheels of the vehicle to be tested on corresponding wheel alignment platforms, with a process hole facing downward in the z direction provided at the bottom of the door sill beam of the vehicle to be tested;

[0045] d. Adjust the position of the docking end of the vehicle body excitation device so that the process holes of the docking end are aligned in the z direction and fixedly connected;

[0046] e. Start the vehicle body excitation device to apply synchronous z-axis excitation to the vehicle to be tested, thereby achieving whole vehicle excitation.

[0047] In the above method, the main weight of the vehicle is borne by the four wheel alignment members, and the docking end only needs to provide the thrust required for the vehicle to generate vibration. Compared with the existing technical solutions, the performance requirements of the equipment are lower and it is easier to implement. In this embodiment, the two body excitation devices work synchronously to couple the excitation of the body, which can further reduce the thrust requirements of the equipment. In addition, during the body excitation process, the vehicle is stably supported by the wheel alignment platform. Even if the body excitation device fails, it will not affect the safety of the entire vehicle. During the excitation process, relevant personnel can enter the interior of the vehicle or the bottom of the vehicle to observe abnormal noises, which is safer and more convenient than the existing technology. In addition, the present invention can be adapted to different models of vehicles by adjusting the installation position of the wheel alignment platform and the body excitation device, and has wide applicability in the detection of abnormal noises in the entire vehicle. It should be noted that the longitudinal centerline actually refers to the longitudinal centerline of the vehicle after it is placed on the wheel alignment platform. Since the setting position of the wheel alignment platform corresponds to the final placement position of the vehicle, the wheel alignment platform can also be considered to have a longitudinal centerline.

[0048] In other implementations, the vehicle abnormal sound test bench may also use multiple excitation groups, and the multiple excitation groups work together to achieve vehicle body excitation.

[0049] It should be noted that the above whole vehicle excitation method does not strictly limit the operation order of each step. For example, in the first embodiment, the position of the process hole can be determined by pre-computation, at this time, the vehicle body excitation device can be installed first and then the vehicle is placed on the wheel positioning table, that is, step b is performed first and then step c is performed. In the second embodiment, the vehicle can be placed on the wheel positioning table first, and then the vehicle body excitation device is installed according to the position of the process hole, that is, step c is performed first and then step b is performed.

[0050] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features, as long as they are within the spirit and principles of the present application. Any modification, equivalent replacement, improvement, etc. made shall be included in the protection scope of the present application.

Claims

1. A body excitation device, characterized by: The vehicle body excitation device comprises a mounting base, a power mechanism, a transmission assembly and a docking assembly; the power mechanism comprises a mounting frame fixedly connected with the base and a vibration exciter connected with the mounting frame; the transmission assembly comprises a transmission force arm and a hinged seat fixedly connected with the base; a hinged base is formed in the middle of the transmission force arm and is connected with the hinged seat and limited in the y direction; the hinged base is connected with a first force arm extending towards the vibration exciter and a second force arm extending in the x direction; the first force arm is in transmission connection with the vibration exciter; the docking assembly comprises a connecting base block fixedly connected with the second force arm and a docking end head fixedly connected with the connecting base block and arranged in the z direction; the hinged seat comprises elastic hinged sheets and first and second end blocks fixedly connected with the two ends of the elastic hinged sheets respectively; the first and second end blocks are fixedly connected with the mounting base and the connecting base block respectively; the elastic hinged sheets comprise first and second hinged sheets parallel to the y direction and perpendicular to each other; the docking assembly comprises a mounting guide rod extending in the z direction, an adjusting frame and a locking member; the connecting base block is provided with a guide hole arranged in the z direction and matched with the lower end of the mounting guide rod; the adjusting frame is sleeved with the upper end of the mounting guide rod; and the locking member is fixedly connected with the outer periphery of the mounting guide rod.

2. A body excitation device according to claim 1, characterised in that: The vehicle body excitation device further comprises an elastic limiting member; the elastic limiting member comprises elastic sheets and first and second positioning portions arranged at the two ends of the elastic sheets; the first and second positioning portions are fixedly connected with the base and the connecting base block respectively and make the elastic sheets arranged perpendicular to the z direction.

3. A body excitation device according to claim 2, characterised in that: The elastic limiting member comprises first and second elastic sheets parallel to each other and arranged in the z direction; the first ends of the first and second elastic sheets are integrally connected through a first positioning portion; the second ends of the first and second elastic sheets are each provided with a second connecting portion; the connecting base block is provided with a first matching portion corresponding to the first elastic sheet and a second matching portion corresponding to the second elastic sheet.

4. A body excitation device according to claim 1, characterised in that: The length of the first force arm is greater than that of the second force arm.

5. A body excitation device according to claim 1, characterized in that: The intersection line of the planes where the first and second hinged sheets are located is defined as a hinged axis; the first hinged sheet is coincident with the second hinged sheet after rotating 90° around the hinged axis.

6. A body excitation device according to claim 1, characterized in that: The adjusting frame comprises an upper base plate, a lower base plate and a support plate; the upper and lower base plates are parallel to each other; the two ends of the support plate are connected with the edges of the upper and lower base plates respectively; the lower base plate is provided with an adjusting hole through which the mounting guide rod passes; and the docking end head is fixedly connected with the upper base plate.

7. A body excitation device according to claim 1, characterized in that: The vehicle body excitation device further comprises an air bag assembly; the air bag assembly comprises a mounting outer frame and first and second air bags arranged inside the mounting outer frame; the end portion of the first force arm is connected with an extension portion; and the first and second air bags are respectively abutted with the two sides of the extension portion in the movement direction.

8. A whole vehicle excitation method, comprising the following steps: a. providing a base, the upper side of the base being provided with a horizontal mounting surface, a plurality of wheel positioning tables corresponding to the number of wheels of a vehicle to be tested being fixed on the horizontal mounting surface according to the structure of the vehicle to be tested, and the upper end of each wheel positioning table being provided with an arc-shaped table surface for placing a wheel. b. fixing at least one vibration excitation group on the horizontal mounting surface, each vibration excitation group comprising two body excitation devices according to any one of claims 1-7 symmetrically arranged with respect to the longitudinal center line of the wheel alignment platform; c. placing each wheel of the vehicle to be tested on the corresponding wheel alignment platform; d. the bottom of the rocker beam of the vehicle to be tested is provided with a process hole facing downward in the z direction, and the docking end of the body excitation device is adjusted so that the process hole is aligned in the z direction and fixedly connected; e. starting the body excitation device to apply synchronous z-direction excitation to the vehicle to be tested, i.e. to realize whole vehicle excitation.

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