Dynamic adjustment method of rolling wheel load of reverse loading type pavement accelerated loading device

Abstract

This invention discloses a dynamic adjustment method for the compaction wheel load of a reverse-loading type road surface accelerated loading device, belonging to the field of accelerated loading experimental technology. This dynamic adjustment method establishes an optimized force distribution model for the vertical force application device by setting up an adjustable upward vertical force application device. The model aims to minimize energy consumption and is constrained by the vertical force application range, the range of the vertical force application rate of the vertical force application device, the expected value of the compaction wheel load at different spatial positions, and the mechanical model of the device itself. This model obtains the expected value of the upward vertical force under the condition of satisfying the expected compaction wheel load. The upward vertical force applied by the vertical force application device is adjusted according to the expected value of the upward vertical force, thereby adjusting the compaction wheel load and achieving the purpose of compacting the experimental road surface at different spatial positions according to the expected compaction wheel load during the movement of the compaction wheel.

Description

Technical Field

[0001] This invention relates to the problem of dynamic adjustment of wheel load in reverse loading road surface accelerated loading equipment, and belongs to the field of accelerated loading experimental technology. Background Technology

[0002] Accelerated loading experiments are an effective means of continuously compacting test pavements with controlled wheel loads to achieve cumulative damage to the pavement in a short period of time, providing a basis for theoretical research and precise design of road structure and material properties.

[0003] Road surface acceleration loading devices are specialized equipment used for accelerated loading experiments, including reverse loading road surface acceleration loading devices. Reverse loading road surface acceleration loading devices consist of a compaction wheel and a main body. The compaction wheel is positioned below and supports the main body, transferring the weight of the device itself to the test road surface to achieve the purpose of compacting the test road surface.

[0004] The rolling pressure of existing reverse loading road surface acceleration equipment cannot be dynamically adjusted during the experiment, which affects the experimental results. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for dynamically adjusting the compaction wheel load of a reverse-loading road surface acceleration loading device. To achieve the above objective, this invention adopts the following technical solution:

[0006] A method for dynamically adjusting the compaction wheel load of a reverse-loading type road surface acceleration loading device, characterized by comprising the following steps:

[0007] 1) Equip the road surface acceleration loading device with a vertical force application device that can apply an upward vertical force to it, wherein the upward vertical force F applied by the vertical force application device can be adjusted and varied;

[0008] 2) Establish a coordinate system o-xyz, with the direction of the upward vertical force F as the z-axis, the direction of motion of the compaction wheel of the road surface acceleration loading device as the x-axis, and the direction perpendicular to the plane containing the x-axis and z-axis as the y-axis; the coordinates of the center of gravity of the road surface acceleration loading device in the xy plane are (x... cg y cg );

[0009] 3) Set the expected value of the compaction wheel load at coordinate x of the experimental road surface to F. T (x);

[0010] 4) With the goal of minimizing energy consumption, based on the vertical force balance equation, the moment balance equation of the accelerating loading device around the x-axis and y-axis, and considering the range of the upward vertical force F that the vertical force application device can apply, the range of the rate of change of the upward vertical force F, and the expected value of the compaction wheel load F, the following criteria are determined: T(x) represents the constraint condition, and the expected values ​​of the upward vertical force F and the rolling wheel load F are constructed. T The force allocation optimization model;

[0011] 5) Obtain the current x-axis coordinate x0 of the compaction wheel and the current value F0 of the upward vertical force F; calculate the expected value of the compaction wheel load F based on the force distribution optimization model constructed in step 4). T The expected value of the upward vertical force F when (x);

[0012] 6) Adjust the upward vertical force applied by the vertical force application device according to the expected value of the upward vertical force F obtained in step 5), so that the compaction load of the compaction wheel at position x reaches the expected value F. T (x) enables the adjustment of the rolling wheel load.

[0013] According to some specific embodiments disclosed in this invention, the reverse-loading type road surface acceleration loading device has two compaction wheels, arranged one in front of the other along the compaction direction, with the two compaction wheels located in the middle of the road surface acceleration loading device in the y-axis direction; the expected compaction wheel loads of the two compaction wheels are F and F respectively. T1 F T2 ;

[0014] The number of vertical force-applying devices is four, which are installed at the bottom of the reverse loading road surface acceleration loading device and located at the four corners of the reverse loading road surface acceleration loading device.

[0015] According to some specific embodiments disclosed in this invention, the upward vertical force applied by the four vertical force-applying devices is F. i (i = 1, 2, 3, 4); Upward vertical force F i The current value F of (i = 1, 2, 3, 4) i0 .

[0016] According to some specific embodiments disclosed in this invention, the scale system o-xyz takes the direction of the upward vertical force F1 as the z-axis direction; F2 has the same x-axis coordinate as F1, F4 has the same y-axis coordinate as F1, F3 has the same x-axis coordinate as F4 and the same y-axis coordinate as F2.

[0017] According to some specific embodiments disclosed in this invention, the accelerated loading device is equipped with a human-machine interface for setting experimental parameters and displaying device status. Through the human-machine interface, the expected value F of the compaction wheel load at different x-axis coordinates of the road accelerated loading device can be set. T (x).

[0018] According to some specific embodiments disclosed in this invention, the force allocation optimization model is as follows:

[0019]

[0020] Where ΔT is the control cycle, V is the speed of the rolling wheel, mg is the gravity of the accelerating loading device; the coordinate of the rolling wheel in the y-axis direction is fixed, a is the distance between F4 and F4 in the x-axis direction from the y-axis, and b is the dimension of the accelerating loading device in the y-axis direction.

[0021] According to some specific embodiments disclosed in this invention, the human-machine interface includes a touch screen or a display plus a keyboard.

[0022] According to some specific embodiments disclosed in this invention, a displacement sensor is used to measure the x-axis coordinate of a moving rolling mill in real time.

[0023] According to some specific embodiments disclosed in this invention, the accelerated loading device includes a controller.

[0024] According to some specific embodiments disclosed in this invention, the controller is used for the programming implementation of the force allocation optimization model.

[0025] The beneficial effects of this invention are:

[0026] The method of this invention obtains the desired upward vertical force (desired upward vertical force) by setting up an adjustable vertical force application device and establishing a force distribution optimization model. Based on the desired roller load, the upward vertical force applied by the vertical force application device is adjusted to reach the desired upward vertical force, thereby achieving the desired roller load. By setting desired roller load values ​​for different compaction positions, the roller load can be achieved by adjusting the upward vertical force applied by the vertical force application device. In other words, by adjusting the upward vertical force applied by the vertical force application device, the roller load is adjusted, achieving the purpose of compacting the experimental road surface at different spatial positions according to the desired roller load during roller movement.

[0027] This invention takes into account energy saving and the force limitations of vertical force application devices. It uses an optimization method to dynamically adjust the rolling wheel load of the rolling wheel of the accelerated loading equipment, so that the desired rolling wheel load can be obtained at different spatial positions. Attached Figure Description

[0028] Figure 1 This is a force diagram of a reverse-loading accelerated loading experimental device subjected to simultaneous crushing by two crushing rollers. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0031] 1. Configure vertical force application device

[0032] A vertical force application device is configured for the reverse-loading type road surface acceleration loading equipment (hereinafter referred to as the road surface acceleration loading equipment). The vertical force application device is located at the bottom of the road surface acceleration loading equipment and can apply an upward vertical force F. The upward vertical force F can be adjusted in real time. There can be four vertical force application devices, numbered 1, 2, 3, and 4. The upward vertical force applied by the four vertical force application devices is F. i (i = 1, 2, 3, 4) (where i represents the number of the vertical force application device, the same below); that is, the upward vertical force applied by vertical force application device No. 1 is F1, the upward vertical force applied by vertical force application device No. 2 is F2, the upward vertical force applied by vertical force application device No. 3 is F3, and the upward vertical force applied by vertical force application device No. 4 is F4. Taking the accelerated loading device as roughly rectangular in shape as an example, such as Figure 1 As shown, vertical force application device 1 is located at the front right corner of the road surface acceleration loading device, vertical force application device 2 at the front left corner, vertical force application device 3 at the rear left corner, and vertical force application device 4 at the rear right corner. The two compaction rollers are positioned in the middle of the road surface acceleration loading device along the y-axis, with roller 1 in front and roller 2 behind. The desired roller loads acting on the experimental road surface by the two rollers are denoted as F. T1 and F T2 The expected compaction load of the first compaction roller is F. T1 The expected compaction load of the second compaction roller is F. T2 Upward vertical force F i The values ​​of (i = 1, 2, 3, 4) are controllable. During operation, the four vertical force-applying devices and two compaction rollers jointly support the main body of the road surface acceleration loading equipment. Specifically, the vertical force-applying devices can be hydraulic devices. Each vertical force-applying device is equipped with a force sensor, such as a pressure sensor, capable of monitoring the magnitude of the upward vertical force.

[0033] 2. Establish a mechanical model of the equipment.

[0034] A coordinate system o-xyz is established within the working space of the road surface acceleration loading equipment. The z-axis of the coordinate system o-xyz is the direction of the upward vertical force F, the x-axis is the direction of the rolling wheel's movement, and the y-axis is the direction perpendicular to the plane containing the x and z axes. Specifically, as follows... Figure 1 As shown, the coordinate system o-xyz takes the direction of the upward vertical force F1 applied by vertical force application device No. 1 as the z-axis direction, the direction of movement of the rolling wheel as the x-axis direction, and the direction perpendicular to the plane containing the x-axis and z-axis as the y-axis direction.

[0035] The dimension of the road surface acceleration loading device in the x-axis direction is a, that is, the distance between vertical force application device 1 and vertical force application device 4 is a, and the distance between vertical force application device 2 and vertical force application device 3 is a.

[0036] The dimension of the road surface acceleration loading equipment in the y-axis direction is b, that is, the distance between vertical force application device 1 and vertical force application device 2 is b, and the distance between vertical force application device 3 and vertical force application device 4 is b; the distance between the compaction wheel and vertical force application device 1 and vertical force application device 4 in the y-axis direction is 1 / 2 of the y-axis dimension b of the equipment body.

[0037] The coordinates of the center of gravity of the road surface acceleration loading device in the xy plane are (x cg y cg The coordinates of vertical force application device 1 in the xy plane are (0, 0), the coordinates of vertical force application device 2 in the xy plane are (0, -b), the coordinates of vertical force application device 3 in the xy plane are (-a, -b), the coordinates of vertical force application device 4 in the xy plane are (-a, 0), the coordinates of roller 1 in the xy plane are (x1, -b / 2), and the coordinates of roller 2 in the xy plane are (x2, -b / 2).

[0038] The mass of the accelerated loading device is m, and the vertical force balance equation is as shown in equation (1):

[0039] F1+F2+F3+F4+F T1 +F T2 =mg (1)

[0040] The moment balance equations of the road surface acceleration loading device body about the x-axis and y-axis are as shown in equations (2) and (3):

[0041]

[0042] (F3+F4)a+F T1 ·(-x1)+F T2·(-x2)=mg·(-x cg (3)

[0043] 3. Set the expected value of the compaction wheel load F at location x on the test road surface. T (x).

[0044] All road surface accelerated loading devices are equipped with a human-machine interface (such as a touch screen or a monitor and keyboard) for setting experimental parameters and displaying equipment status. Through this interface, the expected value of the compaction wheel load at different spatial locations x on the experimental road surface can be set. FT(x) .

[0045] 4. Determine the spatial position of the compaction wheel at the current moment.

[0046] The position of the compaction wheel in the x-axis direction (x-axis coordinate of the compaction wheel) is measured in real time using a displacement sensor. Figure 1 The parameters x1 and x2 in the text.

[0047] 5. With the goal of minimizing energy consumption, the vertical force application range of the vertical force application device is [F]. min_i ,F max_i (i = 1, 2, 3, 4), Range of vertical force application rate of change of vertical force of vertical force application device - ΔF max ≤ΔF i ≤ΔF max (i = 1, 2, 3, 4), Expected values ​​of compaction wheel load at different spatial locations FT(x) Using the equipment mechanical model established in step 2 as constraints, an optimization model for force distribution of the force-applying device is constructed.

[0048] Let the current positions of the two rollers be x. 10 and x 20 The current upward vertical force F i The size of (i = 1, 2, 3, 4) is F. i0 (i = 1, 2, 3, 4, control period ΔT, rolling wheel speed V. The optimization objective is to minimize energy consumption, with the vertical force application range of the vertical force application device [F]). mini_ ,F mia ] x i _ (=1,2,3、Vertical force application device, range of vertical force application rate of change -ΔF) max ≤ΔF i ≤ΔF max (i = 1, 2, 3, 4), Expected values ​​of compaction wheel load at different spatial locations FT(x) Using the equipment body mechanical model established in step 2 as constraints, the force distribution optimization model of the vertical force application device shown in equation (4) is obtained:

[0049]

[0050] 6. Use an optimization algorithm to solve the force distribution optimization model of the vertical force application device established in step 5, and obtain the expected force values ​​F of the four vertical force application devices. i (i = 1, 2, 3, 4).

[0051] Using the well-known simplex method, the quadratic force distribution optimization model of the vertical force application device shown in equation (4) is solved to obtain the desired force variation ΔF of the four vertical force application devices. i (i = 1, 2, 3, 4), based on the known F i0 (i = 1, 2, 3, 4), the expected force F applied by the vertical force application device in the next control cycle is obtained. i =F i0 +ΔF i (i = 1, 2, 3, 4) completes the upward vertical force distribution of the four vertical force application devices. That is, according to the expected value of the vertical force application device in the next control cycle (the vertical force that the vertical force application device should apply), the upward vertical force applied by the vertical force application device (the actual applied force) is adjusted so that the rolling wheel load reaches the expected value, thereby realizing the adjustment of the rolling wheel load in the next control cycle.

[0052] 7. Repeat steps 4, 5, and 6 until the desired compaction wheel load F is reset. T (x) or the experiment ends.

[0053] The method of this invention can be implemented by programming in the controller of the accelerated loading device. Specifically, steps 1-7 are programmed and stored in the controller. The controller receives signals or data on the magnitude of the upward vertical force applied by the vertical force application device, and signals or data on the position of the rolling wheel in the x-axis direction (x-axis coordinate of the rolling wheel) measured in real time by the displacement sensor. Then, the received signals or data are calculated by the program in the memory, and the vertical force application device is controlled to apply upward vertical forces of different magnitudes according to the calculation results.

[0054] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for dynamically adjusting the compaction wheel load of a reverse-loading type road surface acceleration loading device, characterized in that, Includes the following steps: 1) Equip the road surface acceleration loading equipment with a vertical force-applying device capable of applying an upward vertical force to it, wherein the upward vertical force applied by the vertical force-applying device... F Adjustable and changeable; The reverse-loading type road surface acceleration loading device has two compaction wheels, positioned one in front of the other along the compaction direction, with the two compaction wheels located in the middle of the road surface acceleration loading device in the y-axis direction; the expected compaction load values ​​of the two compaction wheels are respectively... F T1、 F T2 ; The number of vertical force application devices is four, which are set at the bottom of the reverse loading road surface acceleration loading device and located at the four corners of the reverse loading road surface acceleration loading device; The upward vertical force that the four vertical force-applying devices should apply in the next control cycle is: F i i=1,2,3,4; Upward vertical force F i The current value is F i0 ; 2) With an upward vertical force F The direction is z The axial direction and the direction of movement of the compaction wheel of the road surface acceleration loading equipment are as follows: x Axial direction, and x shaft and z The direction perpendicular to the plane containing the axis is y Establish a coordinate system along the axis. o - xyz The center of gravity of the road surface acceleration loading equipment is in xy The coordinates in the plane are ( x cg ，y cg ); The coordinate system o - xyz With upward vertical force F 1 The direction is z Axial direction; F 2 and F 1 of x The axis coordinates are equal. F 4 and F 1 of y The axis coordinates are equal. F 3 and F 4 of x Equal axis coordinates F 3 and F 2 of y The axis coordinates are equal; 3) Set the expected value of the compaction wheel load at coordinate x of the experimental road surface to be... F T ( x ); 4) With the goal of minimizing energy consumption, based on the vertical force balance equation and the acceleration loading device's rotation... x shaft and y The axial moment balance equation, with respect to the upward vertical force that can be applied by the vertical force-applying device. F Range, upward vertical force F Range of rate of change and expected value of compaction wheel load F T ( x Assuming ) as the constraint, construct an upward vertical force. F Expected value and expected value of compaction wheel load F T The force allocation optimization model; The force allocation optimization model is shown below: ； in, ΔF i x represents the rate of change of the vertical force applied by the vertical force-applying device. 10 and x 20 These are the current positions of the two compaction rollers. ΔT To control the cycle, V The speed of the rolling wheel. mg To accelerate the application of gravity to the loading equipment; the compaction wheel in y The axial coordinates are fixed, and 'a' is... F 4 and F 4 exist x Distance along the axis b To accelerate the loading of the device y Dimensions in the axial direction; 5) Obtain the current moment of the rolling mill wheel. x Axis coordinates x 0 Upward vertical force F current value F 0 Based on the force distribution optimization model constructed in step 4), the calculation results are obtained when the expected value of the compaction wheel load is... F T ( x Upward vertical force F Expected value ； 6) The upward vertical force obtained in step 5) F The desired value is achieved by adjusting the upward vertical force applied by the vertical force-applying device, so that the compaction load of the roller at position x reaches the desired value. F T (x) enables the adjustment of the rolling wheel load.

2. The method for dynamically adjusting the compaction wheel load of the reverse-loading type road surface acceleration loading device according to claim 1, characterized in that, All the accelerated loading devices are equipped with human-machine interfaces for setting experimental parameters and displaying device status. These interfaces allow for the configuration of the road surface accelerated loading device. x Expected values ​​of compaction wheel load at different coordinates of the axis F T ( x ).

3. The method for dynamically adjusting the compaction wheel load of the reverse-loading type road surface acceleration loading device according to claim 2, characterized in that, The human-machine interface includes a touch screen or a display plus a keyboard.

4. The method for dynamically adjusting the compaction wheel load of the reverse-loading type road surface acceleration loading device according to claim 1, characterized in that, Real-time measurement of road surface acceleration loading equipment and compaction rollers using displacement sensors. x Axis coordinates.

5. The method for dynamically adjusting the compaction wheel load of the reverse-loading type road surface acceleration loading device according to claim 1, characterized in that, The accelerated loading device includes a controller.

6. The method for dynamically adjusting the compaction wheel load of the reverse-loading type road surface acceleration loading device according to claim 5, characterized in that, The controller is used for the programming implementation of the force allocation optimization model.

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