Soil bin test bed capable of switching test wheel driving modes

Abstract

The invention discloses a soil bin test bed capable of switching test wheel driving modes, which mainly comprises a soil bin box body, a longitudinal moving module, a loading module, a single-wheel detection module and a data acquisition and control module, the single-wheel detection module is driven and limited by the longitudinal moving module, the horizontal moving speed and the wheel speed can be set by the data control module, and the loading module is used for loading the single-wheel detection module. The loading module controls the longitudinal force and the vertical force borne by the single-wheel detection module, and the single-wheel detection module collects the rotation soil interaction parameters and uploads the rotation soil interaction parameters to the upper computer through the data collection module. The device is designed for solving the problem that an existing soil bin test bed cannot rapidly switch the driving mode of the test wheel, has three working modes, can simulate three working conditions of driven traction of the driven wheel, free rolling of the driving wheel and traction rolling of the driving wheel, facilitates research on the interaction mechanism of wheels with different driving modes and the ground, and improves the test efficiency. The test device has the advantages of controllable test conditions and environmental factors, comprehensive working condition simulation and the like.

Description

Technical Field

[0001] The invention relates to a wheel simulation working condition test device, in particular to a soil trough test bench capable of switching the driving mode of a test wheel. Technical Background

[0002] Vehicle ground mechanics is a discipline that studies the interaction between wheels and the ground. It studies the operating conditions of different wheels under different soil conditions and driving conditions by combining theory with experiments. It has important guiding significance for improving vehicle passing performance, structural optimization of running mechanisms and passability evaluation of various road surfaces.

[0003] Soil trough test is an important means to study the interaction between wheels and the ground. Compared with the field test of the actual vehicle, the indoor soil trough test has the advantages of not being affected by external natural conditions, controllable test environment, low difficulty in obtaining wheel-soil interaction parameters, high precision, and short test cycle. Therefore, the development of a high-performance indoor soil trough test bench is of great significance for the study of vehicle ground mechanics.

[0004] In order to study the working conditions of wheels under different slip rates, existing soil trough test equipment uses the method of simultaneously controlling the wheel speed and the wheel horizontal speed to control the wheel slip rate. The advantage of this method is that it can obtain the wheel-soil interaction parameters and wheel operation parameters under various slip rate conditions, but it has the disadvantage of limited simulation conditions. That is, when both the wheel speed and the horizontal speed are controlled, the soil trough test bench cannot simulate the situation where a single wheel speed is controlled or a single horizontal speed is controlled. These two conditions correspond to the two conditions of free rolling of the driving wheel and traction rolling of the driven wheel during actual operation of the vehicle. In order to overcome the above shortcomings, it is very important to develop a soil trough test equipment that can flexibly switch between multiple working conditions. Summary of the invention

[0005] To solve the above problems, the present invention discloses a soil trough test bench with switchable test wheel driving modes, which has three working modes and can respectively simulate three working conditions: passive traction of driven wheels, free rolling of driving wheels and traction rolling of driving wheels. It can collect the interaction parameters between the test wheels and the ground in real time, including wheel force, slip rate and settlement. At the same time, in some modes, the operating conditions of the test wheels can be controlled by the driving mechanism and the loading mechanism, including the rotation speed, horizontal speed, longitudinal load and vertical load, so as to provide data support for studying the interaction mechanism between wheels with different driving modes and the ground.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A soil trough test bench with switchable test wheel driving modes comprises a test bench bracket, a soil trough box, a single wheel detection module and a data acquisition and control module.

[0008] Furthermore, the test bench bracket includes a fixed module, a longitudinal movement module and a vertical movement module; the fixed module includes a set of profile brackets, and four single-row slide rails and a screw guide rail supported by the fixed module, wherein the single-row slide rails are supported by angle pieces installed on the inner side of the profile bracket columns to ensure that the movement of the slider is not affected by the columns; two sets of pulleys are installed on the short side of the top layer of the fixed module; the screw guide rail is driven by a motor installed at the end of the guide rail; the longitudinal movement module is driven by a screw guide slider, and supported by six single-row slide rail sliders, and connected to a vertical double-row slide rail through structural profiles; two sets of pulleys are installed on the crossbeam of the longitudinal movement module; the vertical movement module connects the single-wheel detection module to the longitudinal movement module through a double-row slide rail slider, so that the single-wheel detection module can move freely in the vertical direction; a transverse loading profile is fixed above the double-row slide rail slider, which can be used to hang C-shaped open weights.

[0009] Furthermore, the single-wheel detection module includes a wheel frame, a wheel force sensing module, a sinking detection module, an angle detection module and a test wheel; the wheel force sensing module is installed between the wheel frame and the test wheel; the sinking detection module is a set of wire position sensors, the main body of which is fixed above the wheel frame and moves vertically with the test wheel, and the end of the wire is fixed on the back of the vertical double-row slide rail and does not move vertically with the test wheel; when the test wheel is a driven wheel, the angle detection module is a set of magnetic encoders, the stator of which is fixed on the outside of the wheel frame, and the rotor is fixed on the test wheel shaft and rotates with the test wheel; when the test wheel is a driving wheel, the angle detection module is a built-in encoder of the hub motor, which directly outputs the test wheel angle through the 485 bus.

[0010] Furthermore, the data acquisition and control module includes a data acquisition module and a control module, which are fixed on the crossbeam of the longitudinal movement module, are wired to the single-wheel detection module, and are responsible for supplying power to the sensors in the single-wheel detection module; the data acquisition and control module is connected to the power supply through a cable management groove fixed under the screw guide rail; the data acquisition module receives wheel force, sinkage and angle data from the single-wheel detection module through the network port and the 485 bus, and packages them into new data packets, which are transmitted to the host computer through low-power Bluetooth; the control module includes a hub motor driver and a screw guide motor driver, which are respectively installed on the longitudinal movement module and the upper short side crossbeam of the fixed bracket, and communicate with the host computer through the 485 to Bluetooth module to realize the control of the driving wheel speed and the longitudinal movement speed of the test wheel.

[0011] Furthermore, the fixed module is connected to the longitudinal moving module by profiles, and the test bench can be switched from a screw drive mode to a test wheel drive mode by removing four connecting profiles; the test wheel module located under the wheel force sensing module in the single-wheel test module is removable and switched to a driving test wheel or a driven test wheel, and the connection interfaces of the two groups of test wheel modules are unified; when the screw drive mode simulates the passive traction condition of the driven wheel, the test wheel is the driven wheel; when the screw drive mode simulates the passive traction condition of the driving wheel, the test wheel is the driving wheel; when the soil trough test bench is in the test wheel drive mode, the test wheel is the driving wheel.

[0012] Furthermore, the soil trough test bench can compensate for the sliding friction caused by the longitudinal single-row slide rail by applying a fixed longitudinal tensile force, and the steps are as follows: first, the loading beam is connected to the beam of the longitudinal moving module through a nylon rope, so that the test wheel is suspended in the air, and the connecting profile is removed to put the soil trough test bench in the test wheel drive mode; then, the single-wheel test module is pulled longitudinally by the tensile sensor to make it move at a constant speed, and the tensile force value at this time is recorded, which is the friction resistance of the single-row slide rail that needs to be compensated; finally, the same longitudinal tensile force is applied through the short side pulley of the fixed module to compensate for the sliding friction generated by the longitudinal single-row slide rail.

[0013] According to the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention can simulate three working conditions by switching the driving mode of the single-wheel test module, namely, passive traction of the driven wheel, free rolling of the driving wheel and traction rolling of the driving wheel. The above three modes are helpful to study the interaction mechanism between the wheels of different driving modes and the ground, and then improve the vehicle's passability. It has the advantages of controllable test conditions and environmental factors, comprehensive working condition simulation and high test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The schematic drawings are helpful for a more detailed understanding of the present invention, and the drawings are as follows:

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the soil trough test device of an embodiment of the present invention when simulating the driving wheel traction rolling working condition;

[0017] Figure 2 It is a schematic diagram of the three-dimensional structure of a fixed module in the soil trough test device according to an embodiment of the present invention;

[0018] Figure 3 It is a schematic diagram of the three-dimensional structure of the longitudinal moving module in the soil trough test device according to an embodiment of the present invention;

[0019] Figure 4 It is a schematic diagram of the three-dimensional structure of the vertical moving module in the soil trough test device according to an embodiment of the present invention;

[0020] Figure 5 It is a schematic diagram of the three-dimensional structure of a single-wheel detection module in the soil trough test device according to an embodiment of the present invention;

[0021] Figure 6 The upper computer software interface of the soil trough test device of the embodiment of the present invention is shown in FIG.

[0022] Figure 7 It is a schematic diagram of the three-dimensional structure of the soil trough test device of an embodiment of the present invention when simulating the free rolling condition of the driving wheel;

[0023] Figure 8 It is a schematic diagram of the three-dimensional structure of the soil trough test device of an embodiment of the present invention when simulating the traction rolling condition of the driven wheel; DETAILED DESCRIPTION

[0024] In order to more clearly illustrate the technical scheme and technical purpose of the present invention, three specific real-time examples are further described in detail below in conjunction with the accompanying drawings.

[0025] Specific implementation method 1: This embodiment provides a soil trough test bench with switchable test wheel drive mode, and simulates the driving wheel traction rolling condition. Its three-dimensional structural schematic diagram is shown as follows Figure 1 As shown, the test bench comprises a test bench bracket, a soil trough box (1), a single wheel detection module (2) and a data acquisition and control module (3), wherein the test bench bracket is responsible for the limiting, driving and loading functions of the single wheel detection module, and the single wheel detection module is responsible for collecting the interaction parameters between the driven wheel or the driving wheel and the ground; the test bench bracket further comprises a fixing module (4), a longitudinal moving module (5) and a vertical moving module (6); wherein the soil trough has an internal dimension of 1865×565×250 mm and is made of 8 mm thick wooden boards, and a layer of geomembrane is laid inside to prevent fine sand from leaking from the gaps in the soil trough; the driving wheel is 40 mm wide and 85 mm in radius, and is driven by a hub motor with a rated torque of 5.5 Nm, and can be used to simulate the driving wheel of an ordinary ground unmanned vehicle (UGV).

[0026] The fixing module (4) is as follows Figure 2 As shown, it includes a set of brackets (402) made of 3030 aluminum profiles, and four single-row V-shaped slide rails (403) supported by the brackets and a screw guide rail (404) with a diameter of 16mm and a pitch of 5mm; the longitudinal movement module (5) is as shown Figure 3As shown, it is driven by a screw guide slider (501) and supported by six single-row slide sliders (502), connected to a vertical double-row slide rail (503), responsible for driving the single-wheel test module to move longitudinally along the soil trough, and the longitudinal movement module contains a plurality of reinforcement profiles for reinforcing the double-row slide rail to prevent it from twisting or bending; the screw guide slider (501) is driven by a 57 stepper motor (401) installed at the end of the guide rail, with a rated output torque of 2.3Nm, and can provide a longitudinal traction force of 2600N through the screw guide rail; the vertical movement module (6) is as shown Figure 4 As shown, the single-wheel detection module (2) is connected to the longitudinal movement module (5) through a set of double-row slide rail sliders (602), so that the single-wheel detection module can move freely in the vertical direction; the vertical movement module also includes a loading beam (601) for applying vertical pressure to the test wheel.

[0027] The single round detection module (2) is as follows Figure 5 As shown, it comprises a wheel frame (201), a wheel force sensing module (202), a sinking detection module (203), a turning angle detection module (204) and a test wheel (205); the wheel force sensing module is a set of six-dimensional force sensors with a measuring range of 100N / 10Nm, which is installed above the wheel frame and connected to the end of the vertical movement module; the driving wheel measures the turning angle of the test wheel through the built-in encoder of the wheel hub motor; the sinking of the test wheel is measured by a wire position sensor, the wire position sensor body is fixed on the vertical displacement module, and the wire end is fixed on the longitudinal displacement module, and the output of the wire position sensor when the test wheel is about to contact the ground is recorded as the initial sinking value, and the actual sinking is equal to the output of the wire position sensor minus the initial sinking value;

[0028] The data acquisition and control module (3) comprises a data acquisition module and a control module. The data acquisition module is fixed on the crossbeam (504) of the longitudinal movement module, receives data from the six-dimensional force sensor through the network port, receives data from the angle detection module and the sinking detection module through the 485 bus, packages the received data into a new data packet, and sends it to the host computer through the low-power Bluetooth module at a frequency of 100 Hz; the control module comprises a wheel hub motor driver and a screw guide rail motor driver, which are respectively installed on the longitudinal movement module and the upper short side crossbeam of the fixed bracket, and communicates with the host computer through the 485 to Bluetooth module to realize the control of the driving wheel rotation speed and the longitudinal movement speed of the test wheel.

[0029] When the soil trough test bench simulates the driving wheel traction rolling condition, the single wheel test module is driven in the longitudinal direction by the friction between the screw guide rail slider and the driving wheel and the ground, and is subject to the ground rolling resistance and the slider rolling resistance. The slider rolling resistance is an additional resistance that does not exist in the actual operation of the vehicle and needs to be compensated. Therefore, the present invention proposes a slider rolling resistance compensation method, and the specific steps are as follows:

[0030] A) First, the loading beam (601) is connected to the beam (504) of the longitudinal moving module through a nylon rope, so that the test wheel is suspended in the air, and the connecting profile (505) is removed to put the soil trough test bench in the test wheel driving mode;

[0031] B) Then, the single-wheel test module is pulled longitudinally by the tension sensor to make it move at a constant speed, and the tension value at this time is recorded, which is the friction resistance of the single-row slide rail that needs to be compensated;

[0032] C) Finally, the same longitudinal pulling force is applied by fixing the short side pulley (405) of the module to compensate for the additional resistance generated by the longitudinal slide rail slider.

[0033] Figure 6 It is the upper computer software interface, which can control the wheel hub motor speed and the horizontal speed of the single wheel detection module. It can collect the six-dimensional force, sinkage, angle and horizontal displacement of the test wheel and write them into the document. Combining the angle and horizontal displacement, the test wheel slip rate can be further obtained through the following formula:

[0034]

[0035] Where r is the radius of the test wheel, ω is the speed of the test wheel, v x is the horizontal speed of the test wheel, and s is the slip rate.

[0036] Specific real-time method 2: This embodiment provides a soil trough test bench with a switchable test wheel drive mode, and simulates the free rolling condition of the drive wheel, such as Figure 7 The difference between this embodiment and the specific implementation method 1 is that the profile connecting the screw guide rail slider in the longitudinal movement module is removed, so that the single wheel detection module is only driven by the friction between the driving wheel and the ground in the longitudinal direction. The other steps are the same as the specific implementation method 1.

[0037] Specific real-time method three: This embodiment provides a soil trough test bench with a switchable test wheel drive mode, and simulates the free rolling condition of the drive wheel, such as Figure 8 As shown. The difference between this embodiment and the specific real-time method one is that the driving wheel in the single-wheel test module is replaced by the driven wheel, so that the single-wheel detection module is only driven by the traction force of the screw guide rail slider in the longitudinal direction; the test wheel angle is measured by a split magnetic encoder, the encoder stator is fixed to the side of the wheel frame, and the encoder rotor is fixed to the driven wheel shaft and rotates with the driven wheel. The other steps are the same as the specific implementation method one.

Claims

1. A soil trough test bench with switchable test wheel drive mode, characterized in that: The invention comprises a test bench bracket, a soil trough box (1), a single wheel detection module (2) and a data acquisition and control module (3), wherein the test bench bracket is responsible for the limit, drive and loading functions of the single wheel detection module, and the single wheel detection module is responsible for collecting the interaction parameters between the driven wheel or the driving wheel and the ground; The test bench bracket comprises a fixed module (4), a longitudinal movement module (5) and a vertical movement module (6); the fixed module (4) is supported by a set of aluminum profile brackets, four single-row slide rails and a screw guide rail, wherein the single-row guide rail plays a supporting role, and the screw guide rail plays a driving role, and is driven by a motor installed at the end of the guide rail; the longitudinal movement module is responsible for driving and limiting the longitudinal movement of the single-wheel detection module along the soil trough, and comprises six supporting sliders, a driving slider, a vertical double-row slide rail and a plurality of structural profiles, wherein the structural profile not only supports the weight of the module, but also plays a role in reinforcing the vertical double-row guide rail and limiting its torsion and bending; the vertical movement module connects the single-wheel detection module (2) to the longitudinal movement module (5) through a set of double-row slide rail sliders, so that the single-wheel detection module can move freely in the vertical direction; the vertical movement module also comprises a loading beam for applying vertical pressure to the test wheel.

2. A soil trough test bench with switchable test wheel drive mode as claimed in claim 1, characterized in that: The single wheel detection module (2) comprises a wheel frame, a wheel force sensing module, a sinking detection module, a turning angle detection module and a test wheel; the wheel force sensing module is connected to the test wheel and the wheel frame and is responsible for measuring the six-dimensional force on the end of the wheel frame; the driving wheel measures the turning angle of the test wheel through a built-in encoder, and the driven wheel measures the turning angle of the test wheel through an external encoder; the sinking of the test wheel is measured by a wire position sensor, the wire position sensor body is fixed on the vertical displacement module, and the wire end is fixed on the longitudinal displacement module, the output of the wire position sensor when the test wheel is about to contact the ground is recorded as the initial sinking value, and the actual sinking is equal to the output of the wire position sensor minus the initial sinking value.

3. A soil trough test bench with switchable test wheel drive mode as claimed in claim 1, characterized in that: The data acquisition and control module (3) comprises a data acquisition module and a control module, which are fixed on the crossbeam of the longitudinal movement module, connected to the single wheel detection module by wire, and communicate with the host computer wirelessly; the data acquisition module receives wheel force, sinkage and rotation angle data from the single wheel detection module, packages them into new data packets, and transmits the data packets to the host computer by wireless communication; part of the functions of the control module are integrated in the circuit board on the longitudinal movement module, connected to the drive wheel hub motor by wire, and receive instructions from the host computer by wireless communication to complete the control of the drive wheel rotation speed; part of the functions of the control module are contained in the host computer, and the host computer directly sends instructions to the motor at the end of the screw guide rail by wire to control the longitudinal movement speed of the single wheel test module.

4. A soil trough test bench with switchable test wheel drive mode as claimed in claim 1, characterized in that: The fixed module (4) is connected to the longitudinal moving module (5) via a profile, and the test bench can be switched from a screw drive mode to a test wheel drive mode by removing part of the connecting profile; the screw drive mode can simulate a passive traction condition of a driven wheel and a passive traction condition of a driving wheel, and the test wheel drive mode can simulate a free rolling condition of a driving wheel; When the screw drive mode simulates the passive traction condition of the driven wheel, the test wheel is the driven wheel, the longitudinal movement module is driven solely by the screw guide rail slider, and the horizontal movement speed of the test wheel is controllable; when the screw drive mode simulates the passive traction condition of the driving wheel, the test wheel is the driving wheel, the longitudinal movement module is driven jointly by the screw guide rail slider and the driving wheel, and the horizontal movement speed and rotation speed of the test wheel are both controllable under the said condition; in the test wheel drive mode, the test wheel is the driving wheel, the longitudinal movement module is driven by the friction force generated by the driving wheel and the ground when the driving wheel rotates, and only the rotation speed of the test wheel is controllable.

5. The soil trough test bench with switchable test wheel driving mode as claimed in claim 1, characterized in that: Two sets of pulleys are installed on the short sides of the top layer of the fixed module (4) for applying a fixed longitudinal pulling force to the longitudinal moving module; two sets of pulleys are installed on the crossbeam of the longitudinal moving module for applying a vertical pulling force to the vertical moving module; a loading crossbeam is installed above the double-row guide rail slider of the vertical moving module for applying a vertical load to the vertical moving module; The soil trough test bench can compensate for the sliding friction caused by the longitudinal single-row slide rail by applying a fixed longitudinal tensile force, and the steps are as follows: first, the loading beam is connected to the beam of the longitudinal moving module through a nylon rope to make the test wheel suspended in the air, and the connecting profile is removed to put the soil trough test bench in the test wheel driving mode; then, the single-wheel test module is pulled longitudinally by the tensile sensor to make it move at a uniform speed, and the tensile force value at this time is recorded, which is the friction resistance of the single-row slide rail that needs to be compensated; finally, the same longitudinal tensile force is applied by the short side pulley of the fixed module to compensate for the sliding friction generated by the longitudinal single-row slide rail.

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