JP2020153672A - Wind tunnel test system, control method of wind tunnel test system and program - Google Patents

Abstract

To enable a vehicle model to be steered on a belt, and to secure safety when the vehicle model deviates from the belt.SOLUTION: A wind tunnel test system 1000 is provided that comprises: a vehicle scale model 100 which grounds on a moving belt 200 moving toward the rear, and includes wheels 110, 120 rolling with movement of the moving belt 200; a wire 400 which supports the vehicle scale model 100 from the front; and a safety device 500 which is coupled to the vehicle scale model 100 from above, and lifts the vehicle scale model 100 from the moving belt 200 in a predetermined case.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wind tunnel experimental system, a control method and a program of the wind tunnel experimental system.

Conventionally, for example, in Patent Document 1 below, regarding a wind tunnel experimental device, a vehicle grounded on a movable moving belt is connected to a load measuring instrument via a suspension wire, and the vehicle is suspended when the vehicle is displaced in the vertical direction. It is described that the amount of tension of the wire is converted into aerodynamic force.

Japanese Unexamined Patent Publication No. 6-341920

In order to accurately reflect the situation of the actual vehicle in the wind tunnel experiment, it is desirable to be able to steer the vehicle model on the moving belt and perform various measurements. On the other hand, if the vehicle model can be steered on the moving belt, the vehicle model may deviate from the moving model when an abnormality occurs. For example, if the vehicle model falls from the moving belt, the vehicle model or the moving belt may be damaged.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to enable the vehicle model to be steered on the belt and when the vehicle model deviates from the belt. It is an object of the present invention to provide a new and improved wind tunnel experimental system, a control method and a program of the wind tunnel experimental system, which can ensure safety.

In order to solve the above problems, according to a certain viewpoint of the present invention, a vehicle model having wheels that are grounded on a belt that moves rearward and rolls as the belt moves, and the vehicle model are supported. A wind tunnel experimental system is provided that includes a support for the vehicle and, in certain cases, a safety device that lifts the vehicle model from above the belt.

The vehicle model can be steered, and the safety device can steer the vehicle model when the steering parameters of the vehicle model exceed a limit value set according to the speed of the vehicle model with respect to the belt. It may be something to lift.

Further, the safety device has a wire connected to the vehicle model from above and an actuator, and lifts the vehicle model by pulling the wire upward in response to the operation of the actuator. You may.

Further, the safety device may have three wires connected to the vehicle model.

Further, the control device includes a camera that captures a reference point installed in front of the vehicle model and a control device that controls the vehicle model based on an image of the reference point captured by the camera. The camera calculates the amount of lateral displacement of the vehicle model from an image of the reference point, and controls the steering of the vehicle model based on the amount of lateral displacement and the speed of the vehicle model with respect to the belt. Is also good.

Further, in order to solve the above problems, according to another aspect of the present invention, the vehicle has wheels that touch the ground on a belt that moves rearward and rolls with the movement of the belt, and can be steered. In the vehicle model, a step of determining whether or not the steering parameter of the vehicle model exceeds the limit value, and when the steering parameter of the vehicle model exceeds the limit value, the vehicle model is mounted on the belt. A method of controlling a wind tunnel experimental system is provided that includes a lifting step.

Further, in order to solve the above problems, according to another aspect of the present invention, the vehicle has wheels that touch the ground on a belt that moves backward and rolls with the movement of the belt, and can be steered. In the vehicle model, a means for determining whether or not the steering parameter of the vehicle model exceeds the limit value, and when the steering parameter of the vehicle model exceeds the limit value, the vehicle model is lifted from the belt. As a means, a program for operating a computer is provided.

As described above, according to the present invention, it is possible to steer the vehicle model on the belt and to ensure safety when the vehicle model deviates from the belt.

It is a schematic diagram which shows the structure of the system which concerns on one Embodiment of this invention. It is a schematic diagram which shows the state which raised the vehicle scale model by a safety device 500. It is a perspective view which shows the vehicle scale model. It is a schematic diagram which shows the region of the image taken by a camera, and the position of the reference LED in the region. It is a schematic diagram which shows the region of the image taken by a camera, and the position of the reference LED in the region. It is a schematic diagram which shows the structure of the control device which steers a front wheel and controls a safety device, and the periphery thereof. It is a flowchart which shows the process which activates a safety device. It is a schematic diagram which shows the controllable steering angle limit value α0. It is a schematic diagram for demonstrating the method of calculating the steering angle θ from the lateral displacement amount y. It is a schematic diagram which shows the structure which calculates the steering angle θ by PID calculation based on the wire angle β and vehicle speed v.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

First, the configuration of the wind tunnel experimental system 1000 according to the embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a system for evaluating dynamic characteristics in a moving belt wind tunnel using a vehicle scale model. As shown in FIG. 1, the wind tunnel experimental system 1000 includes a vehicle scale model 100, a moving belt 200, rollers 300, 310, wires 400, a safety device 500, and a reference LED 600.

The vehicle scale model 100 includes front wheels 110 and rear wheels 120 that are grounded on the moving belt 200 and roll in response to the movement of the moving belt 200 to the rear of the vehicle. The front wheel 110 can be steered on the moving belt 200. More specifically, the front wheels 110 can be steered by a steering rack and a tie rod on which a steering actuator 112 for transmitting a steering force is mounted.

In the wind tunnel experimental system 1000 of the present embodiment, steering control is performed on the moving belt 200 instead of the method of fixing and supporting the vehicle scale model 100 above the moving belt 200, which is used in a general scale wind tunnel. Then, the vehicle scale model 100 is held on the moving belt 200.

The front wheels 110 and the rear wheels 120 do not generate driving force by themselves. Therefore, when the moving belt 200 moves, the wire 400 supports the vehicle scale model 100 from the front in order to prevent the vehicle scale model 100 from being swept backward.

The safety device 500 includes wires 510 for raising the vehicle scale model 100. When the vehicle scale model 100 may deviate from the moving belt 200, the vehicle scale model 100 is raised by pulling the wire 510 in the direction of arrow A1.

Further, the vehicle scale model 100 includes a wheel speed sensor 130 for detecting the wheel speed of the rear wheels 120, the steering actuator 112 described above, and a camera 140 for photographing the reference LED 600 provided in front of the vehicle scale model 100. I have.

FIG. 2 is a schematic view showing a state in which the vehicle scale model 100 is raised by the safety device 500. The lower side of FIG. 2 shows the configuration of the safety device 500. The safety device 500 includes an actuator 520. The actuator 520 drives the member 530 to which the wire 510 is connected in the direction of arrow A2, so that the wire is pulled in the direction of arrow A1 and the vehicle scale model 100 is raised.

FIG. 3 is a perspective view showing the vehicle scale model 100. In the example shown in FIG. 3, the wires 510 are connected to two places in front of the vehicle scale model 100, and the wires 510 are connected to one place behind the vehicle scale model 100. The wire 510 simultaneously lifts the three points of the vehicle scale model 100 upward, and lifts the vehicle scale model 1000 from the moving belt 200 while maintaining the flat surface. The number of wires 510 and the arrangement of the wires 510 for raising the vehicle scale model 100 are not limited to the example of FIG.

As described above, the front wheels 110 can be steered on the moving belt 200. In the present embodiment, the camera 140 included in the vehicle scale model 100 photographs the reference LED 600, measures the amount of misalignment of the reference LED 600 in the photographing region, and steers the front wheels 110 based on the amount of misalignment.

4A and 4B are schematic views showing a region 142 of an image taken by the camera 140 and the positions of the reference LED 600 in the region 142. FIG. 4A shows the state at the time of initial setting, and the reference LED 600 is located in the center of the area 142. The position of the reference LED 600 shown in FIG. 4A is the reference point.

FIG. 4B shows a state in which the position of the reference LED 600 is displaced with respect to FIG. 4A. In FIG. 4B, the amount of deviation from the reference point is determined from the number of pixels. In FIG. 4B, the position of the reference LED 600 is displaced by 2 pixels with respect to FIG. 4A. For example, in the case of 720 dpi, the amount of deviation for one pixel is measured as 0.353 mm. The amount of deviation for one pixel can be appropriately determined in consideration of the specifications of the optical system of the camera 140 and the specifications of the image sensor.

FIG. 5 is a schematic view showing a configuration of a control device 700 that steers the front wheels 110 and controls the safety device 500 and its surroundings. The control device 700 includes a binarized signal processing unit 710 that binarizes the image data captured by the camera 140, and a lateral displacement amount calculation unit 720 that calculates the lateral displacement amount based on the binarized image data. It is configured. Further, the control device 700 includes a vehicle speed acquisition unit 730 that acquires the vehicle speed from the wheel speed detected by the wheel speed sensor 130, a steering amount calculation unit 740 that calculates the steering amount based on the lateral displacement amount and the wheel speed, and the steering amount. Based on this, the steering actuator 112 or the actuator control unit 750 that controls the actuator 520 of the safety device 500 is provided. The vehicle speed acquisition unit 730 may acquire the vehicle speed from the speed of the moving belt 200. Each component of the control device 700 can be configured by a circuit (hardware) or a central processing unit such as a CPU and a program (software) for operating the central processing unit.

As shown in FIG. 5, normally, the steering actuator 112 that steers the front wheels 110 is controlled based on the steering amount calculated by the steering amount calculation unit 740. As a result, wind tunnel measurement can be performed without the vehicle scale model 100 deviating from the moving belt 200.

On the other hand, in an abnormal situation or the like, the steering amount of the front wheels 110 becomes large, and the vehicle scale model 100 may deviate from the moving belt 200. In such a case, the actuator 520 of the safety device 500 is operated, and as shown in FIG. 2, the wire 510 is pulled in the direction of the arrow A1 to raise the vehicle scale model 100. As a result, the vehicle scale model 100 is not in contact with the moving belt 200, and the running vehicle scale model 100 can be safely lifted and the wind tunnel experiment system 1000 can be stopped.

FIG. 6 is a flowchart showing a process of operating the safety device 500. First, in step S10, the wheel speed acquisition unit 730 acquires the wheel speed. In the next step S12, the controllable steering angle limit value α0 is calculated using the threshold value determination graph shown in FIG. 7.

The threshold value determination graph shown in FIG. 7 shows the characteristics of the controllable steering angle limit value α0 (vertical axis) according to the vehicle speed (horizontal axis). As shown in FIG. 7, as the vehicle speed increases, the controllable steering angle limit value α0 decreases. The threshold value determination graph shown in FIG. 7 can be obtained by simulating the convergence of steering with respect to the amount of lateral displacement by a vehicle motion simulation of maintaining the center with the camera 140 and identifying the steering limit. Since there is a limit to the angle at which convergent steering is possible for each speed, the amount of deviation from the reference point is always detected during traveling, and the safety device 500 is operated when the amount of deviation exceeds the threshold value.

In the next step S14, the lateral displacement amount calculation unit 720 calculates the lateral displacement amount y of the reference LED 600 from the image taken by the camera 140.

In the next step S16, the steering amount calculation unit 740 calculates the steering angle θ for returning the position of the reference LED 600 to the initial position shown in FIG. 4A from the lateral displacement amount y. FIG. 8 is a schematic view for explaining a method of calculating the steering angle θ from the lateral displacement amount y, and shows a state in which the vehicle scale model 100 and the reference LED 600 are viewed from above. As shown in FIG. 8, the wire angle β is calculated from the following equation (1) from the lateral displacement amount y calculated from the image captured by the camera 140 and the length of the wire 400 (wire length L).
β = sin ^-1 (y / L) ・ ・ ・ (1)

Steering actuator 112 mounted on the vehicle scale model 100 performs steering control for converging the wire angle β to 0 [deg]. Since the wire angle β changes in linear proportion by controlling the steering angle δ of the steering actuator 112, the following equation (2) holds. Note that λ is a constant unique to the steering actuator 112.
δ * λ = β ・ ・ ・ (2)

The steering angle θ is calculated by the following equation (3). Here, Ks is a coefficient of steering angle and steering angle, and Kv is a coefficient related to vehicle speed. Also, v is the vehicle speed.
θ = Ks (δ * λ) * Kv (1 / V) ・ ・ ・ (3)

When the wire angle β changes due to steering, the steering angle for that angle is set and the control information is updated. Lateral displacement may be calculated by an acceleration sensor as auxiliary information. FIG. 9 is a schematic diagram showing a configuration in which the steering angle θ is calculated by PID calculation based on the wire angle β and the vehicle speed v. In FIG. 9, the image processing unit 760 is a block that calculates the wire angle β based on the image taken by the camera 140, and is the binarized signal processing unit 710, the lateral displacement amount calculation unit 720, and the steering amount calculation unit 740 described above. Corresponds to a part of the configuration of. Further, the block surrounded by the broken line including the PID controller 1 and the PID controller 2 corresponds to the steering amount calculation unit 740.

As described above, in step S16, the steering angle θ for returning the position of the reference LED 600 to the initial position shown in FIG. 4A can be calculated based on the wire angle β and the vehicle speed. In the next step S18, it is determined whether or not the steering angle θ obtained in step S16 is larger than the steering angle limit value α0 obtained in step S12, and if the steering angle θ is larger than the steering angle limit value α0, the step Proceed to S20.

In step S20, the safety device 500 is activated. As a result, as shown in FIG. 2, the vehicle scale model 100 is lifted upward. After step S20, the process ends.

As described above, according to the process of FIG. 6, when the vehicle scale model 100 is laterally displaced, the steering angle θ for returning the position of the reference LED 600 to the initial position shown in FIG. 4A is the steering angle limit value α0. If it is larger than, the safety device 500 is activated. As a result, when the steering angle θ is larger than the limit value α0 determined according to the vehicle speed, the situation such as the vehicle scale model 100 deviating from the moving belt 200 and falling from the moving belt 200 is surely suppressed. it can.

As described above, according to the present embodiment, when the vehicle scale model 100 may deviate from the moving belt 200, the safety device 500 is operated to lift the vehicle model 100. Therefore, it is possible to reliably prevent a situation such as the vehicle scale model 100 falling from the moving belt 200.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

100 Vehicle scale model 110 Front wheels 120 Rear wheels 140 Camera 200 Moving belt 400 Wire 500 Safety device 510 Wire 520 Actuator 700 Control device

Claims (7)

A vehicle model having wheels that touch the ground on a belt that moves toward the rear and roll as the belt moves.
A support part that supports the vehicle model and
A safety device that lifts the vehicle model from above the belt in certain cases,
A wind tunnel experimental system characterized by being equipped with. The vehicle model can be steered
1. The safety device is characterized in that the vehicle model is lifted when the steering parameter of the vehicle model exceeds a limit value set according to the speed of the vehicle model with respect to the belt. Wind tunnel experimental system described in. The safety device includes a wire connected to the vehicle model from above and an actuator, and lifts the vehicle model by pulling the wire upward in response to the operation of the actuator. , The wind tunnel experimental system according to claim 1 or 2. The wind tunnel experimental system according to claim 3, wherein the safety device has three of the wires connected to the vehicle model. A camera that shoots a reference point installed in front of the vehicle model,
A control device for controlling the vehicle model based on an image taken by the camera of the reference point is provided.
The control device calculates the amount of lateral displacement of the vehicle model from an image taken by the camera of the reference point, and controls the steering of the vehicle model based on the amount of lateral displacement and the speed of the vehicle model with respect to the belt. The wind tunnel experimental system according to any one of claims 1 to 4, wherein the wind tunnel experimental system is characterized in that. In a vehicle model that has wheels that touch the ground on a belt that moves rearward and that rolls as the belt moves and that can be steered, whether or not the steering parameter of the vehicle model exceeds the limit value. Steps to judge and
A step of lifting the vehicle model from the belt when the steering parameter of the vehicle model exceeds the limit value.
A control method for a wind tunnel experimental system, which comprises. In a vehicle model that has wheels that touch the ground on a belt that moves rearward and that rolls as the belt moves and that can be steered, whether or not the steering parameter of the vehicle model exceeds the limit value. Judgment means,
A means for lifting the vehicle model from the belt when the steering parameter of the vehicle model exceeds the limit value.
A program to make your computer work as.

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