Nodding simulation device and nodding simulation method for counter-force drum-type brake test platform

Abstract

The invention discloses a nodding simulation device and method for a counter-force drum-type brake test platform, and the device is installed on the counter-force drum-type brake test platform which is provided with a supporting frame and a drum, and comprises an electromagnetic linear driver which is provided with a stator installed on the supporting frame and a rotor located on the stator, and the rotor can be driven by the stator; the transmission part is connected with the rotor; the speed reducer is in driving connection with the transmission part; the force application assembly is connected with the output end of the speed reducer and a tested vehicle chassis; and the control unit is communicated with the counter-force drum-type brake test platform and the electromagnetic linear driver, and can receive and respond to a brake synchronizing signal of the counter-force drum-type brake test platform and start the electromagnetic linear driver. The electromagnetic linear driver, the transmission part, the speed reducer and the force application assembly are used for applying rapid and controllable downward pulling force to a tested vehicle chassis, the vehicle nodding phenomenon caused by braking inertia in a real braking working condition and front axle dynamic load increase can be simulated, and the condition is close to a real road test condition.

Description

Technical Field

[0001] This invention belongs to the field of vehicle inspection and testing technology, and specifically relates to a head-nodding simulation device and method for a reaction roller brake test platform. Background Technology

[0002] The roller reaction brake test bench, as a core piece of equipment for vehicle braking performance testing, primarily evaluates braking performance by measuring the reaction force of the wheel braking force acting on the main roller. According to the national standard GB / T 13564-2020, this type of equipment has formed a standardized technical system, covering detailed regulations on classification and models, technical requirements, and test methods. However, existing technology has significant limitations, making it difficult to accurately simulate real braking test conditions.

[0003] a) Static testing is disconnected from dynamic operating conditions: During actual road braking, a vehicle experiences significant "nose-diving" due to its own inertia and the effect of its suspension system, leading to a redistribution of vehicle weight. The dynamic load on the front axle can increase by 30%-40%, resulting in an actual braking force far exceeding the static test value. However, existing roller reaction brake testing benches operate with the vehicle stationary, making it difficult to reproduce this dynamic load transfer effect. Studies show that this difference causes a significant deviation between bench-tested braking force results and actual road test results, especially for vehicles equipped with ABS systems, where the difference is even more pronounced due to repeated pressure changes.

[0004] b) Difficulty in simulating inertial effects: Existing roller reaction brake benches primarily simulate road surfaces through roller rotation, but lack simulation of the vehicle's overall inertial effects. When a vehicle brakes on a real road surface, inertial forces increase the load on the front axle and decrease the load on the rear axle. Although current test benches can apply axle loads via lifting devices (such as equipment with rated load capacities of 3t, 10t, and 13t), this loading is static and cannot accurately reproduce the dynamic axle load transfer during braking.

[0005] c) Inaccurate ABS system testing: For modern vehicles equipped with ABS systems, the system continuously adjusts braking force during braking to prevent wheel lock-up. Existing testing benches monitor slip ratio using a third roller (typically set to automatically stop at 25%-35%), but this is insufficient to simulate dynamically changing downforce, leading to significant discrepancies between ABS operating conditions and actual conditions. Test data shows that this discrepancy can cause braking force test errors exceeding 15%, resulting in a disconnect between bench testing and actual ABS operating conditions, making it difficult to accurately assess the true braking performance when ABS intervenes.

[0006] Currently, the bench test data of reaction roller brake testing platforms deviate significantly from road test results, making brake system calibration difficult, increasing the frequency and cost of real-vehicle road testing, extending the development cycle, and posing safety hazards. Therefore, its limitations in simulating real-world environments and its inability to simulate the dynamic behavior of the entire vehicle cannot be ignored.

[0007] Therefore, a device is needed to simulate the braking pitch phenomenon when a vehicle brakes, in order to solve the technical problem that the existing roller reaction braking test platform cannot accurately reflect the actual braking conditions. Summary of the Invention

[0008] This invention provides a head-nodding simulation device and method for a reaction roller brake test platform, in order to solve the problem that existing reaction roller brake test platforms cannot accurately reflect actual braking conditions.

[0009] In view of the shortcomings of the prior art, the technical solution adopted by the present invention is as follows: A head-nodding simulation device for a reaction roller brake test platform, for mounting on a reaction roller brake test platform having a support frame and rollers, includes: an electromagnetic linear actuator and a transmission component, the electromagnetic linear actuator including a stator and a mover, the mover being mounted on the stator and the stator being configured to drive the mover to move via a magnetic field; the stator being fixed on the support frame; one end of the transmission component being mounted on the mover and capable of moving with the mover; a reducer and a force-applying component, the reducer being mounted on the support frame and connected to the transmission component, the transmission component being used to drive the reducer to rotate; one end of the force-applying component being connected to the output end of the reducer, and the other end being used to connect to the chassis of the vehicle under test; when the electromagnetic linear actuator drives the transmission component to drive the reducer, the force-applying component can generate a downward force on the vehicle under test; a control unit, the control unit being communicatively connected to the reaction roller brake test platform and the electromagnetic linear actuator, and configured to receive and respond to a braking synchronization signal from the reaction roller brake test platform and activate the electromagnetic linear actuator.

[0010] Based on the aforementioned technical means, this solution communicates with the reaction roller brake test platform and the electromagnetic linear actuator through the control unit. During the brake test, the electromagnetic linear actuator can be used as a power source to drive the transmission components. After the power magnitude is converted by the reducer, the force application component can apply a rapid and controllable downward force to the chassis of the vehicle under test. This accurately simulates the vehicle "nodding" phenomenon caused by braking inertia and the increase in dynamic load on the front axle in real braking conditions, which is close to real road test conditions and improves the accuracy and reliability of the test.

[0011] The head-nodding simulation device in this solution is installed on the existing reaction roller test platform as an additional device. It does not require any changes to the original braking performance test process and equipment structure, is compatible with existing test standards and equipment, and is easy to promote and apply.

[0012] Furthermore, the transmission component is a rack, one end of which is mounted on the mover and can move with the mover; the input end of the reducer meshes with the rack through a gear and is driven by the rack.

[0013] Based on the above technical means, rack and pinion transmission is a mature and efficient mechanical transmission method. It has the characteristics of high transmission efficiency, smooth operation, strong load-bearing capacity, simple structure, rapid response, and can quickly and effectively transmit the drive of the mover and drive the reducer.

[0014] Furthermore, it also includes a limiting slide rail and a limiting slider. The limiting slide rail is installed on the support frame and its length direction is parallel to the moving direction of the transmission component. The limiting slider is slidably installed on the limiting slide rail and can move along the length direction of the limiting slide rail. The rack is connected to the limiting slider.

[0015] Based on the above technical means, the limiting slide rail and the limiting slider provide a stable linear motion guide for the rack, preventing the rack from swaying or shifting when driven by the drive unit, which would cause the rack to fall off the gear at the input end of the reducer, thus ensuring the smoothness and reliability of the rack transmission.

[0016] Furthermore, it also includes a slide rail base, which is mounted on the support frame, and the limiting slide rail is mounted on the slide rail base.

[0017] Based on the above technical means, the slide rail base provides an installation foundation for the limit slide rail, which facilitates the installation and adjustment of the position of the limit slide rail relative to the support frame to adapt to different installation environments and ensure the reliability of the limit slide rail installed on the support frame.

[0018] Furthermore, the force-applying component includes a first pulley, a first cable, and a clamp. The first pulley is installed at the output end of the reducer; the first cable is wound around the first pulley; and the clamp is installed at the free end of the first cable for fixing it to the chassis of the vehicle under test.

[0019] According to the above-mentioned technical means, the cooperation between the first pulley and the first cable can convert the rotational motion output by the reducer into linear motion along the first cable, and then apply the converted linear motion to the vehicle under test through the clamp, forming a downward force on the vehicle under test. The structure is simple and reliable.

[0020] Furthermore, it also includes tension and compression sensors, which are connected to the first cable and the clamp respectively, for measuring in real time the downward force transmitted from the first cable to the vehicle under test through the clamp.

[0021] Based on the above technical means, the tension and compression sensors can monitor the magnitude of the downward force applied to the vehicle under test in real time, which facilitates data collection and processing during testing.

[0022] Furthermore, it also includes a guide wheel, which is mounted on the support frame and is used to guide the first cable.

[0023] Based on the above technical means, the guide wheel guides the first cable, enabling the first cable to be connected to the chassis of the vehicle under test from a suitable position and angle, thereby improving the adaptability of the first cable to the chassis of the vehicle under test.

[0024] Furthermore, the transmission component is a second cable and also includes a second pulley, which is installed at the input end of the reducer; the second cable is wound around the second pulley and one end is fixed to the mover of the electromagnetic linear actuator.

[0025] Based on the above technical means, when the installation space is limited, the second cable, as a flexible component, can realize a non-linear transmission layout, which improves the adaptability of the device.

[0026] The present invention also provides a method for conducting vehicle braking performance tests using a head-nodding simulation device as described in any of the above claims, comprising the following steps: S1. Test preparation: Drive the vehicle under test onto the reaction roller brake test platform equipped with the head-nodding simulation device, and connect the force application component to the chassis of the vehicle under test. Based on the mass, wheelbase, center of gravity height of the vehicle under test and the vehicle testing requirements, the vehicle simulation parameters are set in the control unit. The vehicle simulation parameters include the target value of downforce, the timing of downforce application, and the duration of downforce. S2. Start-up test: Start the braking performance test. The control unit receives the braking synchronization signal from the reaction roller brake test platform and generates control commands based on the braking synchronization signal. S3, Loading Simulation: The control unit starts the electromagnetic linear drive according to the control command, so that the electromagnetic linear drive outputs linear driving force according to the vehicle simulation parameters, and applies a downward force to the vehicle under test through the transmission component, the reducer and the force application component; S4. Data Acquisition and Processing: Real-time acquisition of vehicle braking force data measured by the reaction roller brake test platform and downward force measured by the tension and compression sensors during the braking performance test, and generation of vehicle braking performance test results.

[0027] Furthermore, the target value for the downforce is 0~30kN.

[0028] Based on the aforementioned technical means, the range of pull-down force values ​​can cover the simulated demand for the increase in front axle dynamic load during emergency braking, from light passenger cars to some heavy commercial vehicles.

[0029] Beneficial effects: 1. This solution communicates with the reaction roller brake test platform and the electromagnetic linear actuator through the control unit. During the brake test, the electromagnetic linear actuator can be used as a power source to drive the transmission components. After the power is converted by the reducer, the force application component can apply a fast and controllable downward force to the chassis of the vehicle under test. This accurately simulates the "nodding" phenomenon of the vehicle caused by braking inertia and the increase of dynamic load on the front axle in real braking conditions, which is close to the real road test conditions and improves the accuracy and reliability of the test.

[0030] 2. The head-nodding simulation device in this solution is installed on the existing reaction roller test platform. As an additional device to the existing reaction roller test platform, it does not require changes to the original braking performance test process and equipment structure. It is compatible with existing test standards and equipment, making it easy to promote and apply. Attached image description: Figure 1 This is a schematic diagram of the nodding simulation device of the present invention installed on a reaction roller brake test platform; Figure 2 for Figure 1 Enlarged view of the structure at point A in the middle; Figure 3 This is a top view of the reducer of the present invention with a first pulley installed at the output end; Figure 4 This is a cross-sectional view of the speed reducer of the present invention; Figure 5 This is a flowchart of the method of the present invention; Figure 6 This is a flowchart of the electromagnetic linear actuator outputting linear driving force in Example 3.

[0031] Figure label: 100. Reaction roller brake test platform; 110. Support frame; 120. Roller; 200. Electromagnetic linear actuator; 210. Stator; 220. Mover; 300. Transmission component; 400. Reducer; 410. Output end; 420. Gear; 430. Input end; 500. Force application component; 510. First pulley; 520. First cable; 530. Fixture; 610. Limiting slide rail; 620. Limiting slider; 630. Slide rail base; 700. Guide wheel.

[0032] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The same or similar reference numerals correspond to the same or similar components. The terms describing positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. Detailed Implementation

[0033] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0034] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0035] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0036] In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium.

[0037] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0038] Example 1 like Figures 1 to 4 As shown, this embodiment provides a nodding simulation device for a reaction roller brake test platform 100, which is installed on the reaction roller brake test platform 100 having a support frame 110 and a roller 120. It includes: an electromagnetic linear actuator 200 and a transmission component 300. The electromagnetic linear actuator 200 includes a stator 210 and a mover 220. The mover 220 is mounted on the stator 210, and the stator 210 is configured to drive the mover 220 to move via a magnetic field. The stator 210 is fixed to the support frame 110. One end of the transmission component 300 is mounted on the mover 220 and can move with the mover 220. A reducer 400 and a force application component 500 are also included. The 0 is mounted on the support frame 110 and connected to the transmission component 300, which is used to drive the reducer 400 to rotate; one end of the force application component 500 is connected to the output end 410 of the reducer 400, and the other end is used to connect to the chassis of the vehicle under test; when the electromagnetic linear actuator 200 drives the transmission component 300 to drive the reducer 400, the force application component 500 can generate a downward force on the vehicle under test; the control unit is communicatively connected to the reaction roller brake test platform 100 and the electromagnetic linear actuator 200, and is configured to receive and respond to the braking synchronization signal from the reaction roller brake test platform 100 and start the electromagnetic linear actuator 200.

[0039] When using the head-nodding simulation device in this embodiment to test the braking performance of a vehicle, the front wheels of the vehicle under test are placed on the roller 120, the rear wheels are fixed to a plane, and the clamp 530 is connected to the bearing point of the front suspension in the chassis. The simulation parameters of the vehicle under test are preset in the control unit according to the basic parameters of the vehicle (mass, wheelbase, center of gravity height, etc.) and test requirements (such as conventional test, ABS performance test). During the braking performance test, when the brake pedal is pressed and the vehicle under test is triggered to brake, the reaction roller brake test platform 100 detects the start of braking force and generates a braking synchronization signal. The generated braking synchronization signal is then transmitted to the control unit. The control unit generates a control command for the electromagnetic linear actuator 200 based on the braking synchronization signal, causing the electromagnetic linear actuator 200 to start working (specifically, the stator 210 generates a precisely controlled magnetic field, driving the mover 220 to move along the linear slide rail of the stator 210 in a very short time), and driving the transmission component 300 to move. The transmission component 300 then transmits the power to the chassis of the vehicle under test through the reducer 400 and the force application component 500, simulating the "nodding" phenomenon of the vehicle during braking.

[0040] In this embodiment, the reducer 400 is preferably a planetary gear reducer.

[0041] In this embodiment, the control unit is connected to the reaction roller brake test platform 100 and the electromagnetic linear actuator 200. During the brake test, the electromagnetic linear actuator 200 can be used as a power source to drive the transmission component 300. After the power is converted by the reducer 400, the force application component 500 can apply a fast and controllable downward force to the chassis of the vehicle under test. This accurately simulates the "nodding" phenomenon of the vehicle caused by braking inertia and the increase in dynamic load on the front axle in real braking conditions, which is close to the real road test conditions and improves the accuracy and reliability of the test. The braking force simulation device in this embodiment reduces the deviation between the braking force test results and the road test to within 5% through dynamic loading, which can truly reflect the axle load transfer effect during braking and provide reliable data for the development and calibration of braking systems. This is more scientific and reasonable for accurately evaluating vehicle braking performance, especially for judging vehicles at the critical state of braking efficiency. For vehicles equipped with ABS systems, this device can simulate dynamically changing axle load transfer (by driving the rack to reciprocate through a linear electromagnetic actuator, causing the input end 430 of the planetary gear reducer to rotate clockwise and counterclockwise, which in turn causes the output end 410 of the planetary gear reducer to drive the first pulley 510 to rotate, so that the first cable 520 can be wound back or extended, applying a dynamically changing downward force to the chassis of the vehicle under test), making the ABS working conditions closer to the actual situation.

[0042] In this embodiment, the head-nodding simulation device is installed on the existing reaction roller 120 test platform. As an additional device to the existing reaction roller 120 test platform, it does not require changes to the original braking performance test process and equipment structure. It is compatible with existing test standards and equipment, meets the requirements of GB / T 13564-2020 standard, and is easy to promote and apply.

[0043] like Figure 1 As shown, in this embodiment, the transmission component 300 is a rack, with one end mounted on the mover 220, allowing it to move with the mover 220. The input end 430 of the reducer 400 meshes with the rack via a gear 420, thus being driven by the rack. Rack and pinion transmission is a mature and efficient mechanical transmission method, characterized by high transmission efficiency, smooth operation, and strong load-bearing capacity. It also features a simple structure and rapid response, quickly responding to the drive of the mover 220 and driving the reducer 400. The gear 420 is connected to the input end 430 of the reducer 400 to achieve torque amplification. The reduction ratio of the reducer 400 can be designed from 10:1 to 50:1 as needed.

[0044] like Figure 1 and Figure 2As shown, this embodiment also includes a limiting slide rail 610 and a limiting slider 620. The limiting slide rail 610 is mounted on the support frame 110, and its length direction is parallel to the moving direction of the transmission component 300. The limiting slider 620 is slidably mounted on the limiting slide rail 610 and can move along the length direction of the limiting slide rail 610. The rack is connected to the limiting slider 620. The limiting slide rail 610 and the limiting slider 620 provide stable linear motion guidance for the rack, preventing the rack from swaying or shifting when driven by the drive element 220, which could cause the rack to fall off the gear 420 at the input end 430 of the reducer 400, thus ensuring the smoothness and reliability of the rack transmission.

[0045] like Figure 1 and Figure 2 As shown, this embodiment also includes a slide rail base 630, which is mounted on the support frame 110, and a limiting slide rail 610 is mounted on the slide rail base 630. The slide rail base 630 provides an installation foundation for the limiting slide rail 610, facilitating the installation and adjustment of the position of the limiting slide rail 610 relative to the support frame 110 to adapt to different installation environments and ensure the reliability of the limiting slide rail 610 mounted on the support frame 110.

[0046] like Figure 1 river Figure 3 As shown, in this embodiment, the force-applying component 500 includes a first pulley 510, a first cable 520, and a clamp 530. The first pulley 510 is installed at the output end 410 of the reducer 400; the first cable 520 is wound around the first pulley 510; the clamp 530 is installed at the free end of the first cable 520 for fixing it to the chassis of the vehicle under test. The cooperation of the first pulley 510 and the first cable 520 can convert the rotational motion output by the reducer 400 into linear motion along the first cable 520, and then apply the converted linear motion to the vehicle under test through the clamp 530, forming a downward pulling force on the vehicle under test. The structure is simple and reliable. The output end 410 of the reducer 400 is fixed with a large-diameter first pulley 510, and the first cable 520 is wound around the first pulley 510. The rotation of the first pulley 510 realizes the winding and unwinding of the first cable 520. The length of the first cable 520 is adjustable from 1.5 to 3m. The 530 clamp features an adaptive chuck design that allows for quick connection to vehicle chassis anchor points with different structures. The adaptive chuck has a self-locking function to ensure that it will not accidentally come off during the application of downward force.

[0047] This embodiment also includes a tension / compression sensor, which is connected to the first cable 520 and the clamp 530 respectively. The sensor is used to measure in real time the downward force transmitted from the first cable 520 to the vehicle under test through the clamp 530. The tension / compression sensor can monitor the magnitude of the downward force applied to the vehicle under test in real time, facilitating data acquisition and processing during testing. Specifically, in this embodiment, an S-type tension / compression sensor with a range of 0-20kN and an accuracy class of C3 (±0.05%FS) is selected. It is connected in series between the end of the first cable 520 and the clamp 530, and connected via a universal joint to eliminate lateral force interference. The S-type tension / compression sensor has a built-in temperature compensation resistor, an operating temperature range of -20℃ to +80℃, and its signal can be sent to the control unit via the CAN bus. This allows the control unit to adjust the movement of the electromagnetic linear actuator 200 based on the tension value measured by the S-type tension / compression sensor, ensuring that the downward force applied by the first cable 520 to the vehicle under test is the same as the target value.

[0048] like Figure 1 As shown, in this embodiment, a guide wheel 700 is also included, which is mounted on the support frame 110. Figure 1 (Diagram showing the removal of one side baffle of support frame 110) is used to guide the first cable 520. The guide wheel 700 guides the first cable 520, enabling the first cable 520 to be connected to the chassis of the vehicle under test from a suitable position and angle, thus improving the adaptability of the first cable 520 to the chassis of the vehicle under test.

[0049] In summary, the head-nodding simulation device in this embodiment automates and automates the testing process, obtaining vehicle braking data close to real road braking conditions in a single test, eliminating the need for repeated road tests and comparisons, significantly reducing the number of high-risk road tests, shortening the R&D cycle by approximately 30%, and greatly improving testing efficiency. This provides assistance in promoting the development of automotive braking performance testing technology towards the integration of "virtual and reality".

[0050] Example 2 This embodiment is another implementation of the transmission component 300 in Embodiment 1, and the difference from Embodiment 1 is that: In this embodiment, the transmission component 300 is a second cable (not shown in the attached drawings), and also includes a second pulley, which is mounted on the input end 430 of the reducer 400; the second cable is wound around the second pulley, and one end is fixed to the mover 220 of the electromagnetic linear actuator 200. When the installation space is limited, the second cable, as a flexible component, can realize a non-linear transmission layout, improving the structural adaptability of this device.

[0051] In this embodiment, adaptively, the support frame 110 may not be equipped with such a feature. Figure 1 and Figure 2The slide rail base 630, the limiting slide rail 610 and the limiting slider 620 shown are directly connected to one end of the second cable via the mover 220 of the electromagnetic linear actuator 200.

[0052] It is worth noting that, in this embodiment, apart from the implementation method of the transmission component 300 and the corresponding adaptive changes, the other structures and the installation methods of the structures are the same as in Embodiment 1.

[0053] Example 3 This embodiment provides, as follows: Figure 5 The method shown employs a head-nodding simulation device as described in Embodiment 1 or Embodiment 2 for testing vehicle braking performance, and includes the following steps: S1. Test preparation: Drive the vehicle under test onto the reaction roller brake test platform 100 equipped with a nodding simulation device, and connect the force application component 500 to the chassis of the vehicle under test. Based on the mass, wheelbase, center of gravity height of the vehicle under test, and the vehicle testing requirements, the vehicle simulation parameters are set in the control unit. The vehicle simulation parameters include the target downforce value, the timing of downforce application, and the duration of downforce. S2. Start-up test: Start the braking performance test. The control unit receives the braking synchronization signal from the reaction roller brake test platform 100 and generates control commands based on the braking synchronization signal. S3, Loading Simulation: The control unit starts the electromagnetic linear actuator 200 according to the control command, so that the electromagnetic linear actuator 200 outputs linear driving force according to the vehicle simulation parameters, and applies a downward force to the vehicle under test through the transmission component 300, the reducer 400 and the force application component 500. S4. Data Acquisition and Processing: Real-time acquisition of vehicle braking force data measured by the reaction roller brake test platform 100 and downward force measured by the tension and compression sensors during the braking performance test, and generation of vehicle braking performance test results.

[0054] During the start-up braking performance test, the control unit calculates and generates the target value of downforce in real time based on the braking synchronization signal generated by the reaction roller brake test platform 100 and the simulated parameters of the vehicle under test. The controller calculates the target value of downforce dynamically changing in the range of 0-30kN in real time based on the vehicle parameters and braking conditions, using one or more combinations of theoretical mechanical models, preset MAP diagrams, or sensor closed-loop feedback (all of which are existing technologies). The target value of downforce is then converted into a motion signal of the electromagnetic linear actuator 200.

[0055] Furthermore, the target downforce is 0~30kN.

[0056] Based on the aforementioned technical means, the range of pull-down force values ​​can cover the simulated demand for the increase in front axle dynamic load during emergency braking, from light passenger cars to some heavy commercial vehicles.

[0057] Specifically, such as Figure 6 As shown, when using the test method of the head-nodding simulation device in Example 1 or Example 2 to test the braking performance of the vehicle under test: The tension and compression sensors are connected to the control unit. After the electromagnetic linear actuator 200 outputs linear driving force, when a downward force is applied to the chassis of the vehicle under test, the tension and compression sensors feed back the actual downward force value to the control unit in real time. The control unit calculates the deviation based on the actual downward force value and the target downward force value, and compares the obtained deviation with the deviation threshold preset in the control unit (the deviation threshold for passenger cars can be set to 0.2kN-0.3kN; the deviation threshold for commercial vehicles can be set to 0.5-0.8kN).

[0058] When the actual deviation is greater than the deviation threshold, the control unit corrects the displacement command of the electromagnetic linear actuator 200, causing the electromagnetic linear actuator 200 to output linear driving force again until the actual deviation of the pull force is less than the deviation threshold. When the actual deviation is less than the deviation threshold, the reaction roller brake test platform 100 records the instantaneous braking force of the test vehicle's wheels in real time, and the control unit can perform the next control cycle of applying the target value of the pull force to the test vehicle (to track the updated target value of the pull force). When the braking performance test is completed, the control unit outputs the complete vehicle braking performance test results.

[0059] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor feasible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A head-nodding simulation device for a reaction roller brake test platform, for mounting on a reaction roller brake test platform (100) having a support frame (110) and a roller (120), characterized in that, include: An electromagnetic linear actuator (200) and a transmission element (300) are provided. The electromagnetic linear actuator (200) includes a stator (210) and a mover (220). The mover (220) is mounted on the stator (210) and the stator (210) is configured to drive the mover (220) to move by a magnetic field. The stator (210) is fixed to the support frame (110). One end of the transmission element (300) is mounted on the mover (220) and is movable with the mover (220). The reducer (400) and the force application component (500) are mounted on the support frame (110) and connected to the transmission component (300), which is used to drive the reducer (400) to rotate; one end of the force application component (500) is connected to the output end (410) of the reducer (400), and the other end is used to connect to the chassis of the vehicle under test. The control unit is communicatively connected to the reaction roller brake test platform (100) and the electromagnetic linear actuator (200), and is configured to receive and respond to the brake synchronization signal from the reaction roller brake test platform (100) and start the electromagnetic linear actuator (200).

2. The head-nodding simulation device for a reaction roller brake test platform according to claim 1, characterized in that, The transmission component (300) is a rack, one end of which is mounted on the mover (220) and can move with the mover (220); the input end (430) of the reducer (400) meshes with the rack through a gear (420) and is driven by the rack.

3. The head-nodding simulation device for a reaction roller brake test platform according to claim 2, characterized in that, It also includes a limiting slide rail (610) and a limiting slider (620). The limiting slide rail (610) is mounted on the support frame (110) and its length direction is parallel to the moving direction of the transmission member (300). The limiting slider (620) is slidably mounted on the limiting slide rail (610) and can move along the length direction of the limiting slide rail (610). The rack is connected to the limiting slider (620).

4. The head-nodding simulation device for a reaction roller brake test platform according to claim 3, characterized in that, It also includes a slide rail base (630), which is mounted on the support frame (110), and the limiting slide rail (610) is mounted on the slide rail base (630).

5. The head-nodding simulation device for a reaction roller brake test platform according to claim 1, characterized in that, The force application component (500) includes a first pulley (510), a first cable (520), and a clamp (530). The first pulley (510) is installed at the output end (410) of the reducer (400). The first cable (520) is wound around the first pulley (510). The clamp (530) is installed at the free end of the first cable (520) and is used to fix it to the chassis of the vehicle under test.

6. A head-nodding simulation device for a reaction roller brake test platform according to claim 5, characterized in that, It also includes a tension and compression sensor, which is connected to the first cable (520) and the clamp (530) respectively, and is used to measure in real time the downward force transmitted from the first cable (520) to the vehicle under test through the clamp (530).

7. A head-nodding simulation device for a reaction roller brake test platform according to claim 5, characterized in that, It also includes a guide wheel (700) mounted on the support frame (110) for guiding the first cable (520).

8. A head-nodding simulation device for a reaction roller brake test platform according to claim 1, characterized in that, The transmission component (300) is a second cable and also includes a second pulley, which is installed at the input end (430) of the reducer (400); the second cable is wound on the second pulley and one end is fixed on the mover (220) of the electromagnetic linear actuator (200).

9. A method, employing a head-nodding simulation device as described in any one of claims 1-8, for conducting vehicle braking performance testing, characterized in that, Includes the following steps: S1. Test preparation: Drive the vehicle under test onto the reaction roller brake test platform (100) equipped with the head-nodding simulation device, and connect the force application component (500) to the chassis of the vehicle under test. Based on the mass, wheelbase, center of gravity height of the vehicle under test and the vehicle testing requirements, the vehicle simulation parameters are set in the control unit. The vehicle simulation parameters include the target value of downforce, the timing of downforce application, and the duration of downforce. S2, Start-up Test: Start the braking performance test. The control unit receives the braking synchronization signal from the reaction roller brake test platform (100) and generates control commands based on the braking synchronization signal. S3, Loading Simulation: The control unit starts the electromagnetic linear actuator (200) according to the control command, so that the electromagnetic linear actuator (200) outputs linear driving force according to the vehicle simulation parameters, and applies a downward force to the vehicle under test through the transmission component (300), the reducer (400) and the force application component (500); S4. Data Acquisition and Processing: Real-time acquisition of vehicle braking force data measured by the reaction roller brake test platform (100) and downward force measured by the tension and compression sensors during the braking performance test, and generation of vehicle braking performance test results.

10. A method according to claim 9, characterized in that, The target value for the downforce is 0~30kN.

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