Apparatus, method and program for simulation

Abstract

To improve the reproduction accuracy of simulation.SOLUTION: A radar simulator 1 identifies as a target polygon a polygon against which a radar wave formed by simulation hit out of a plurality of polygons having as an apex three-dimensional coordinate point group showing a three-dimensional shape of an object surface by a set of three-dimensional coordinate points represented on a three-dimensional coordinate. The radar simulator 1 computes, based on a Bezier curved plane computed by performing curved-plane interpolation on a plane of the target polygon, a hit point where the radar wave hit against the Bezier curved plane.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a simulation device, a simulation method, and a simulation program for forming a wave motion by simulation. [Background technology]

[0002] Patent Document 1 describes a method for performing tessellation in a computer graphics system. Tessellation is a technique for further dividing a large number of polygons (e.g., triangular polygons) used to represent a three-dimensional solid object, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-4516 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, advanced safety features for automobiles have been expanding. In order to streamline the development process, in addition to performance checks using test equipment, computer simulations are increasingly being used to reproduce driving environments and check performance, and there is a demand for improved accuracy.

[0005] The advanced safety features are realized by using external recognition sensors to recognize the environment outside the vehicle. The external recognition sensors include active sensors and passive sensors. Examples of active sensors include radar devices, sonar, and LiDAR. Examples of passive sensors include cameras.

[0006] An active sensor emits radio waves, ultrasonic waves or light and receives the power reflected by external objects to recognize objects in the external world. Computer simulations calculate how much power is returned when radio waves, ultrasound or light emitted by the sensor hits objects around the vehicle, such as people, cars and roads.

[0007] In particular, for radio wave and ultrasonic power, not only the magnitude of the power but also the phase (i.e., the degree to which the power waves are shifted in time) is an important factor in accurately calculating the received power. Regarding the specific phenomenon of phase, for example, when two powers are received at the same time, if they are received with the same phase, the powers are amplified, but if they are received with the opposite phase, the powers cancel each other out and disappear.

[0008] This phase fluctuates at the moment of reflection from the surface of an object, and fluctuates as the wave travels through space. In order to reproduce the portion that fluctuates as the wave propagates through space, it is important that the shape of the object is accurately represented. In the case of millimeter wave radar, the wavelength is about a few millimeters, and a deviation of just 1 mm in the propagation distance can result in a very large error in the received power.

[0009] In computer simulations, the shape of an object is often expressed by connecting polygons, but when it comes to objects with curved surfaces, it is impossible to make them match the ideal shape.

[0010] As a result of detailed investigation by the inventors, it was found that the phase of a wave colliding with an object differs between reality and simulation, which can cause a significant error in the calculation of the received power in the simulation.

[0011] The present disclosure aims to improve the reproducibility of simulations. [Means for solving the problem]

[0012] One aspect of the present disclosure is a simulation device (1) including a polygon identification unit (S10) and a collision position correction unit (S20 to S40). The polygon identification unit is configured to identify, as a target polygon, a polygon with which a wave formed by the simulation collides, among a plurality of polygons whose vertices are a group of three-dimensional coordinate points that indicate the three-dimensional shape of the object surface by a collection of three-dimensional coordinate points represented by three-dimensional coordinates.

[0013] The collision position correction unit is configured to calculate a collision point at which the wave collides with the target curved surface, based on the target surface, which is a curved surface calculated by performing surface interpolation on a plane of the target polygon.

[0014] The simulation device of the present disclosure configured in this manner can reduce the difference between the position where a wave collides with a real object and the position where the wave collides with an object reproduced in the simulation, thereby improving the reproduction accuracy of the simulation.

[0015] Another aspect of the present disclosure is a simulation method in which a simulation device identifies, as a target polygon, a polygon with which a wave formed by simulation collides, among a plurality of polygons whose vertices are a group of three-dimensional coordinate points that indicate the three-dimensional shape of an object surface by a collection of three-dimensional coordinate points represented in three-dimensional coordinates, and the simulation device calculates the collision point at which the wave collides with the target surface, based on the target surface, which is a curved surface calculated by performing surface interpolation on the plane of the target polygon.

[0016] The simulation method of the present disclosure configured in this manner is a method executed by the simulation device of the present disclosure, and by executing this method, it is possible to obtain the same effects as the simulation device of the present disclosure.

[0017] Yet another aspect of the present disclosure is a simulation program (24) for causing a computer to function as a polygon identifying unit (S10) and a collision position correcting unit (S20 to S40).

[0018] A computer controlled by the simulation program of the present disclosure can constitute part of the simulation device of the present disclosure, and can obtain the same effects as the simulation device of the present disclosure. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a block diagram showing a configuration of a radar simulator. [Diagram 2] 13 is a flowchart showing a collision position correction process. [Diagram 3] FIG. 13 is a diagram illustrating setting and movement of a control point. [Figure 4] FIG. 13 is a diagram showing collision points on a polygon and collision points on a Bezier surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The radar simulator 1 of this embodiment includes a display unit 11, an operation input unit 12, a data storage unit 13, a data input / output unit 14, and a control unit 15, as shown in FIG.

[0021] The display unit 11 includes a display device (not shown) and displays various images on the display screen of the display device. The operation input unit 12 outputs input operation information for identifying an input operation performed by a user via a keyboard and a mouse (not shown).

[0022] The data storage unit 13 is a storage device for storing various data. The data input / output unit 14 inputs and outputs data to and from an external device connected via a wire or wirelessly.

[0023] The control unit 15 is mainly composed of a microcomputer including a CPU 21, a ROM 22, a RAM 23, etc. Various functions of the microcomputer are realized by the CPU 21 executing a program stored in a non-transitive substantial recording medium. In this example, the ROM 22 corresponds to the non-transitive substantial recording medium storing the program. Furthermore, the execution of this program executes a method corresponding to the program. Note that some or all of the functions executed by the CPU 21 may be configured in hardware using one or more ICs, etc. Also, the number of microcomputers constituting the control unit 15 may be one or more.

[0024] A simulation program 24 is stored in the ROM 22. The simulation program 24 may be pre-installed in the radar simulator 1, or may be installed from a recording medium or via a network. Examples of the recording medium include an optical disk, a magnetic disk, and a semiconductor memory.

[0025] The simulation program 24 is configured to use highly accurate three-dimensional map data to reproduce the three-dimensional shape of a road and the three-dimensional shape of the area around the road in a virtual space, and to drive a vehicle on the road reproduced in this virtual space.

[0026] In this embodiment, the three-dimensional map data is a three-dimensional coordinate point cloud that indicates the three-dimensional shape of the object surface by a set of coordinate points represented by three-dimensional coordinates. The simulation program 24 is configured to reproduce the three-dimensional shape in the virtual space by generating a large number of polygons (triangular polygons in this embodiment) with each of the multiple three-dimensional coordinate points that constitute the three-dimensional coordinate point cloud as a vertex.

[0027] Furthermore, the simulation program 24 is configured to simulate the transmission and reception of radar waves by a radar device mounted on a vehicle traveling in a virtual space. By starting the simulation program 24 stored in the ROM 22, a radar simulation is executed which simulates the running of a vehicle and the transmission and reception of radar waves by the radar device.

[0028] Next, a procedure for a collision position correction process for correcting a collision position where a radar wave collides with an object in a radar simulation will be described. The collision position correction process is started after the end of a transmission wave generation process for generating radar waves (hereinafter, transmission waves) transmitted by a radar device in a radar simulation. The transmission wave generation process is executed every time a preset radar wave transmission period elapses in a virtual space formed by the radar simulation.

[0029] When the collision position correction process is executed, the CPU 21 of the control unit 15 calculates the collision position where the radar wave collides with the polygon in S10 as shown in Fig. 2. The collision position is calculated based on the propagation path of the radar wave and the position of the three-dimensional coordinate point group. This identifies the polygon where the radar wave collides (hereinafter, the target polygon).

[0030] In step S20, the CPU 21 sets a control point b i,j,k Set the initial position of . As shown in Figure 3, the control point b of the target polygon i,j,k The initial positions of the control points b are set to the vertices of the triangle, the positions that divide each side of the triangle into three equal parts, and the center of gravity of the triangular faces. i,j,k control point b i It is sometimes written as follows.

[0031] b i,j,k In the case of Bezier interpolation used in this embodiment, "i+j+k=3" is used to represent the control points by i, j, and k. Control point b on triangle ABC iis expressed by the formula (1). In the formula (1), A, B, and C are vectors indicating the coordinate positions of the vertices A, B, and C of the triangle ABC. In this embodiment, since the triangle is of the third degree (i.e., n=3), the control point b i is expressed by equation (2).

[0032]

number

[0033] As shown in FIG. 2, in order to generate a curved surface from the target polygon, the CPU 21 calculates a control point b b from the normal vectors n0, n1, and n2 (hereinafter, vertex normal vectors n0, n1, and n2) of the three vertices constituting the target polygon according to the formulas (3) to (12). i Move the control point b'. i is calculated by the control point b i The vectors v0, v1, and v2 in equations (3) to (12) are the positions of the control points b 3,0,0 ,b 0,3,0 ,b 0,0,3 is a vector indicating the position of

[0034]

number

[0035] As shown in FIG. 3, normal vectors n0, n1, and n2 are normal vectors at vertices A, B, and C, respectively. Equations (3) to (11) are the closest control point b i The edge extending to the control point b is perpendicular to the vertex normal vector. i This is the formula for moving the control point b 3,0,0 ,b 0,3,0 ,b 0,0,3 is a vertex. Therefore, the control point b 3,0,0 ,b 0,3,0 ,b 0,0,3 The position of does not change.

[0036] Equation (12) is the control point b 1,1,1 is another control point b i,j,k This is a formula for making the amount of movement larger than As shown in FIG. 2, in step S40, the CPU 21 calculates the control point b' i Based on the position of the radar wave and the collision position calculated in S10, the collision position on the Bezier surface where the radar wave collided is calculated, and the collision position correction process is terminated.

[0037] The impact position where the radar wave hits the target polygon and the positions of the control points are expressed in barycentric coordinates. Barycentric coordinates are expressed as a three-component vector u = (u, v, w). Barycentric coordinates indicate how close an arbitrary point on a triangle is to each of the triangle's vertices. The sum of u, v, and w is always 1, and the position vector p indicating the position of an arbitrary point on triangle ABC is expressed by equation (13). The order of u, v, and w from left to right in equation (13) is w, u, v to make calculations easier.

[0038]

number

[0039] The Bezier surface is expressed by equations (14) and (15). In equation (14), n is the degree of the Bezier surface. The vector u is the collision position. B(u) is the Bernstein coefficient. i, j, k are the control point numbers. n (u) is the position on the Bezier surface that corresponds to the collision position. b' i is the control point b' moved in S30 i This is the location.

[0040]

number

[0041] In this embodiment, the degree of the Bezier surface (i.e., n) is 3. Therefore, the CPU 21 calculates the collision position b 3Calculate (u).

[0042]

number

[0043] The radar simulation executes a collision position correction process every time a radar wave is generated, thereby calculating a collision position on the Bezier surface where the radar wave collides. 4, the radar simulation calculates, for example, the position of a collision point IP1 where a radar wave W1 collides with a polygon PG1. Then, the radar simulation calculates a position on a Bezier surface BC1 of the polygon PG1 that corresponds to the collision point IP1 as a corrected collision point CIP1.

[0044] Similarly, the radar simulation calculates, for example, the position of a collision point IP2 where the radar wave W2 collides with the polygon PG2. Then, the radar simulation calculates a position on the Bezier surface BC2 of the polygon PG2 that corresponds to the collision point IP2 as a corrected collision point CIP2.

[0045] The radar simulation then calculates the timing at which the radar device receives the radar waves, the received power, and the like, based on the corrected radar waves reflected at the collision points CIP1 and CIP2.

[0046] The radar simulator 1 configured in this manner is configured to identify, as a target polygon, a polygon with which the radar wave formed by the simulation collides, among a plurality of polygons whose vertices are a group of three-dimensional coordinate points that indicate the three-dimensional shape of the object surface by a collection of three-dimensional coordinate points represented by three-dimensional coordinates.

[0047] The radar simulator 1 is also configured to calculate a collision point where the radar wave collides with the Bezier surface, based on the Bezier surface calculated by performing surface interpolation on the plane of the target polygon.

[0048] Such a radar simulator 1 can reduce the difference between the position where the radar wave collides with a real object and the position where the radar wave collides with an object reproduced in the simulation, thereby improving the reproduction accuracy of the simulation.

[0049] In the embodiment described above, the radar simulator 1 corresponds to a simulation device, the radar wave corresponds to a wave motion, S10 corresponds to processing as a polygon identification unit, the Bezier surface corresponds to a target surface, and S20 to S40 correspond to processing as a collision position correction unit.

[0050] Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment and can be implemented in various modified forms. [Variation 1] In the above embodiment, a radar wave is formed as a wave motion by simulation, but an electromagnetic wave, an ultrasonic wave, or light may be formed as a wave motion.

[0051] [Variation 2] In the above embodiment, the three-dimensional shape of the object surface is reproduced using triangular polygons. However, the three-dimensional shape of the object surface may be reproduced using polygons having a polygonal shape other than a triangle.

[0052] [Variation 3] In the above embodiment, a form in which a Bézier surface is calculated by performing surface interpolation is shown, but the method of converting a planar polygon into a curved surface is not limited to the method of calculating a Bézier surface, and any method may be used.

[0053] [Variation 4] In the above embodiment, the position on the Bézier surface corresponding to the collision position on the triangular polygon is calculated as the position where the radar wave collides with the Bézier surface. However, the position of the intersection between the target surface, which is a surface calculated by performing surface interpolation on the plane of the target polygon, and the propagation path of the radar wave formed by simulation may be calculated as the position of the collision point where the radar wave collides with the target surface.

[0054] The control unit 15 and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit 15 and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit 15 and the method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer. The method for realizing the functions of each unit included in the control unit 15 does not necessarily need to include software, and all of the functions may be realized using one or more hardware.

[0055] In the above embodiments, multiple functions of one component may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0056] In addition to the above-described radar simulator 1, the present disclosure can also be realized in various forms, such as a system including the radar simulator 1 as a component, a program for causing a computer to function as the radar simulator 1, a non-transient physical recording medium such as a semiconductor memory on which this program is recorded, and a simulation method. [Explanation of symbols]

[0057] 1... radar simulator, 15... control unit, 24... simulation program

Claims

1. a polygon identification unit (S10) configured to identify, as a target polygon, a polygon with which a wave generated by a simulation collides, among a plurality of polygons having vertices of a group of three-dimensional coordinate points that indicate a three-dimensional shape of an object surface by a set of three-dimensional coordinate points represented by three-dimensional coordinates; a collision position correction unit (S20 to S40) configured to calculate a collision point at which the wave collides with the target curved surface based on the target curved surface, the target surface being a curved surface calculated by performing surface interpolation on a plane of the target polygon; A simulation device (1) comprising:

2. The simulation device according to claim 1 , The collision position correction unit A simulation device that sets a plurality of control points inside the plane of the target polygon formed by connecting three or more of the vertices with straight lines, moves the control points using a vertex normal, which is the normal at the vertices, so that the edge extending from the vertex to the nearest control point is perpendicular to the vertex normal, and performs surface interpolation on the plane of the target polygon based on the position of the moved control point.

3. a simulation device specifies, as a target polygon, a polygon with which a wave motion formed by the simulation collides, among a plurality of polygons having vertices each of which is a group of three-dimensional coordinate points that indicate a three-dimensional shape of an object surface by a set of three-dimensional coordinate points represented by three-dimensional coordinates; A simulation method in which a simulation device calculates a collision point at which the wave collides with a target curved surface, the target surface being a curved surface calculated by performing surface interpolation on a plane of the target polygon.

4. Computer, a polygon identification unit (S10) configured to identify, as a target polygon, a polygon with which a wave generated by a simulation collides, among a plurality of polygons having vertices of a group of three-dimensional coordinate points that indicate a three-dimensional shape of an object surface by a set of three-dimensional coordinate points represented by three-dimensional coordinates; A collision position correction unit (S20 to S40) configured to calculate a collision point at which the wave collides with the target curved surface based on the target curved surface, which is a curved surface calculated by performing surface interpolation on a plane of the target polygon. A simulation program (24) for functioning as a

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