CN104408989A - Rearview mirror simulation method for vehicle driving simulation system - Google Patents

Abstract

The invention discloses a rearview mirror simulation method for a vehicle driving simulation system. The method comprises the following steps: firstly, obtaining specific position and coordinate of a vehicle according to vehicle motion, capturing a rearview mirror scene by a rearview mirror camera to obtain a rearview mirror top point coordinate required to be drawn, connecting top points in sequence to form a rearview mirror surface which is rearview mirror texture, and finally pasting the rearview mirror texture onto a rearview mirror model; during driving simulation, pre-binding initial texture, replacing old texture with new texture in real time through a created pointer function, and finally finishing simulation of a whole rearview mirror. According to the method, the rearview mirror effect is creatively displayed on a vehicle model in a three-dimension manner, so that the trouble caused by occupation of main view angle can be avoided, the refresh rate of the system can be reduced, and the vividness of whole driving simulation can be improved; the method has good commercial values.

Description

A kind of rearview mirror emulation mode for vehicle simulation control loop

Technical field

The present invention relates to a kind of rearview mirror emulation mode for vehicle simulation control loop, being specifically related to one can according to riding manipulation needs, and manual control also can in the rearview mirror effect of the upper dynamic simulation vehicle of display (or display screen).

Background technology

At present, in vehicle simulation control loop, wherein the research of rearview mirror emulation is less, only have by windows display technology at present, in driver visual angle, increase a rearview mirror passage, although can accomplish that rearview mirror emulates like this, but take visual angle, front, and if window is too small, it is clear that rearview mirror is not fogging; Window is excessive, has covered front sight line.

During actual driving, rearview mirror is very crucial safety component for driver.Because whole analogue system is drive simulating, driver is when handling real vehicle or controlling virtual vehicle, have stronger stereoscopic sensation and feeling of immersion, the important component part of driving simulation is not only in rearview mirror emulation, is also an important channel of improving whole control loop verisimilitude.

The principle of the anatomy that the Yang Xiujie of Shenyang Univ. of Science and Engineering is comparatively detailed in document " application of OpenGL technology in vehicle mirrors imaging " virtual emulation rearview mirror in vehicle simulation is driven and main process, it utilizes OpenGL imaging mechanism, manufacture larger improvement to rearview mirror imaging is limited, but still have deficiency.The rearview mirror emulation that it produces takies driver's main perspective, and does not have stereoscopic sensation, a just window.The rearview mirror imaging of design just can need obtain through six large conversion, and process is comparatively loaded down with trivial details; And according to simulated effect figure, two auxiliary viewports occupy main viewport, have blocked the sight line of front buildings, therefore this rearview mirror effect is not very desirable.

According to the shortcoming of above-mentioned document and in conjunction with actual rearview mirror situation, need the rearview mirror emulation realized will have stereoscopic sensation and stronger verisimilitude, and be consistent with actual rearview mirror.And visual angle, driver front can not be taken, comprise the scenery in vehicle window and front; In sum, a kind of such rearview mirror emulation mode must be designed independently, could above-mentioned requirements be met.

Summary of the invention

Object: in order to overcome the deficiencies in the prior art, the invention provides a kind of rearview mirror emulation mode for vehicle simulation control loop.

Technical scheme: for solving the problems of the technologies described above, the technical solution used in the present invention is:

For a rearview mirror emulation mode for vehicle simulation control loop, rearview mirror image adopts texture phase, realizing rearview mirror effect, specifically comprising the following steps by dynamically replacing texture in real time:

1), obtain vehicle drive time scene coordinate, utilize vehicle dynamic model obtain vehicle at three-dimensional system of coordinate x, the coordinate in y, z, and running attitude three-dimensional perspective α, beta, gamma, arranges simulation step length T; The basic exercise of vehicle can be divided into straight line and turning: controlled vehicle can carry out the driving under any operating mode in a program, and comprising advances keeps straight on, and turns to and drives and brake and reversing, by setting up vehicle dynamic model to realize;

2), utilize rearview mirror relative to the inactive of vehicle body, obtain rearview mirror camera coordinates, wherein rearview mirror camera is rotatable, is convenient to the scene catching rear view of vehicle; Arrange rotation matrix, in conjunction with coordinate and the running attitude three-dimensional perspective α of vehicle location, beta, gamma, adjusts rearview mirror camera;

3), scene read in frame buffer and create rearview mirror texture, rectangle is roughly in conjunction with actual rearview mirror shape, set up a rectangle initial texture and bound, its memory value is needed to empty before binding, definition initial texture is true value, and initial texture is set to dynamically, when vehicle movement, the rearview mirror texture of establishment is replaced in real time;

4), by newly-generated texture undertaken intercepting and change, the coordinate figure on rearview mirror four summits being carried out algebraic manipulation and obtains rearview mirror texture size; In order to rearview mirror texture can be allowed correctly to show rearview mirror scene, and meet real vision, the vision of people should be that nearly person is large, farther is little, by arranging view frustums and carrying out projective transformation, projective transformation matrix is set, projective transformation matrix and rotation matrix premultiplication have just been carried out projective transformation;

5) conversion, between increase rearview mirror texture coordinate and screen coordinate, ensures that the texture of generation and actual rearview mirror scene match,

6), by texture coordinate be mapped on rearview mirror model, finally play up whole scene; In order to prevent the phenomenon of the rearview mirror image retention that vehicle mutation movement produces, pointer function head it off is set; By the initial texture of pointed, and the whole process of replacing in real time texture is encapsulated as a R function, achieves by this function of bar repeatedly the object that cycle alternation exports rearview mirror effect.

Preferably, step 1) in " controlled vehicle can carry out the driving under any operating mode in a program, and comprising advances keeps straight on, and turns to and drives and brake and reversing, by setting up vehicle dynamic model to realize " refer to:

1a), straight line model adopts Euler method emulation to obtain instantaneous velocity and the coordinate of vehicle; Suppose that the acceleration of vehicle remains unchanged in a simulation step length T, then the travel speed change discrete model of vehicle is:

$v(t+1)=v\left(t\right)+a\left(t\right)T=v\left(t\right)+\frac{T}{\mathrm{\δ}\·m}[F_t\left(t\right)-F_b\left(t\right)-F_f\left(t\right)-F_i\left(t\right)-F_w\left(t\right)]$

Wherein, v (t+1), v (t) is for vehicle is at the instantaneous velocity of t+1, t; T is simulation step length; δ is vehicle rotary quality coefficient; M is motor vehicle equipment quality; F _tfor Automobile drive power; F _bfor automobile acceleration resistance; F _ffor automobile resistance to rolling; F _ifor automobile grade resistance; F _wfor air resistance of automobile;

Just the concrete coordinate of t+1 moment vehicle can be obtained according to the algebraic manipulation of t vehicle coordinate and speed;

1b), vehicle is when occurring to turn, and utilizes steering angle θ to obtain the coordinate of angle and the particular location residing for vehicle of turning; Suppose that certain moment automobile driving speed is v (t), front wheel angle rotates δ ' angle, then have:

$\frac{{\mathrm{\ω}}_r}{{\mathrm{\δ}}^{,}}=\frac{v\left(t\right)/L}{1+\mathrm{Kv}{\left(t\right)}^2}$

K is stability factor; L is vehicle wheel base; ω _rfor stable state yaw velocity;

After elapsed time dt, automobile turns over d θ on inceptive direction, then motor turning mathematical model is:

$\frac{\mathrm{d\θ}}{\mathrm{dt}}={\mathrm{\ω}}_r=\frac{v\left(t\right)L}{1+\mathrm{Kv}{\left(t\right)}^2}\·{\mathrm{\δ}}^{,}$

Again arrange:

$\mathrm{d\θ}=\frac{v\left(t\right)/L}{1+\mathrm{Kv}{\left(t\right)}^2}\·{\mathrm{\δ}}^{,}\·\mathrm{dt}$

Just the coordinate after turn inside diameter can be calculated by angle θ;

1c), when vehicle is in pitching, yaw, side direction, Full Vehicle Dynamics model is utilized to obtain running attitude three-dimensional perspective α, beta, gamma.

Preferably, step 2) in " arrange rotation matrix, in conjunction with coordinate and the running attitude three-dimensional perspective α of vehicle location, beta, gamma, adjusts rearview mirror camera " specifically refer to:

With vehicle body direction for x-axis, horizontal vertical is y-axis in vehicle body direction, and system vertical is that z-axis sets up three-dimensional cartesian coordinate system in direction, ground; If earth axes XYZ is that { A}, rearview mirror camera coordinates system xyz (or vehicle body coordinate system) are { B}, so rearview mirror camera coordinates system { any point P in B} ^bat earth axes { the coordinate P in A} ^acan be calculated by following relation:

$M(z,\mathrm{\α})=\left[\begin{array}{ccc}\cos \mathrm{\α}& -\sin \mathrm{\α}& 0\\ \sin \mathrm{\α}& \cos \mathrm{\α}& 0\\ 0& 0& 1\end{array}\right]$

$M(y,\mathrm{\β})=\left[\begin{array}{ccc}\cos \mathrm{\β}& 0& \sin \mathrm{\β}\\ 0& 1& 0\\ -\sin \mathrm{\β}& 0& \cos \mathrm{\β}\end{array}\right]$

$M(x,\mathrm{\γ})=\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\γ}& -\sin \mathrm{\γ}\\ 0& \sin \mathrm{\γ}& \cos \mathrm{\γ}\end{array}\right]$

Wherein M (z, α) is for rearview mirror camera is around the rotation matrix at z-axis rotation alpha angle, and M (y, β) to rotate the rotation matrix at β angle for camera around y-axis, and M (x, γ) to rotate the rotation matrix at γ angle for camera around x-axis; When vehicle pose changes, camera also synchronously makes corresponding change, connects successively after calculating the coordinate on backsight minute surface 4 summits.

Preferably, step 4) in projective transformation matrix as follows:

$M^P=\left[\begin{array}{cccc}\frac{2n}{r-l}& 0& -\frac{r+l}{r-l}& 0\\ 0& \frac{2n}{t-b}& -\frac{t+b}{t-b}& 0\\ 0& 0& \frac{f}{f-n}& -\frac{\mathrm{fn}}{f-n}\\ 0& 0& 1& 0\end{array}\right]$

T, b, l, r are the vertical range of backsight minute surface to top, upper and lower, left and right; N is the distance of viewpoint to view frustums hither plane; F is the distance of viewpoint to view frustums far plane.

Preferably, step 5) in conversion between rearview mirror texture coordinate and screen coordinate in the following way:

$A_x=B_x\×\frac{\mathrm{width}}{2}+\frac{\mathrm{width}}{2}$

$A_y=\frac{\mathrm{height}}{2}-B_y\×\frac{\mathrm{height}}{2}$

Wherein, A _xfor the lateral coordinates of texture coordinate, A _yfor the longitudinal coordinate of texture coordinate, B _x, B _ybe respectively screen coordinate lateral coordinates and longitudinal coordinate, Width is the length of rearview mirror model, and Height is the wide of rearview mirror model.

Described a kind of rearview mirror emulation mode for vehicle simulation control loop, is characterized in that: the stereo display of rearview mirror effect is on vehicle mirrors model; The emulation of this rearview mirror does not take main perspective, i.e. driver visual angle; When searching out vehicle mirrors model and meeting related request, program judges and maps, otherwise continue repeat step 1)-step 6) and action.

Described a kind of rearview mirror emulation mode for vehicle simulation control loop, is characterized in that: vision simulation refresh rate can not lower than 24hz, and whole emulation does not affect main line process, does not namely affect real-time; By pointed initial texture, and the whole process of replacing in real time texture is encapsulated as a R function, realizes by bar R function repeatedly the object that cycle alternation exports rearview mirror effect, simultaneously also not influential system frame per second.

Beneficial effect: a kind of rearview mirror emulation mode for vehicle simulation control loop provided by the invention, based on the rearview mirror emulation that dynamic texture maps, utilize the geo-stationary of rearview mirror and vehicle movement, by virtual reality technology by the scene stereo display of rear view of vehicle and below on rearview mirror, and can on rearview mirror, make adjustment timely according to vehicle change and upgrade, be not only vehicle to be kept in motion, be applicable to vehicle stationary state too, be also applicable to rearview mirror effect when vehicle movement is undergone mutation; Therefore be a kind ofly drive with actual vehicle the rearview mirror also more true to nature that matches and emulate.Compare the research of original forefathers, stereo display, in real time dynamic mapping, not acceptor's angle limitations, the emulation that can realize under various working are several large novel point of the application; The development of virtual reality technology, vehicle simulation is driven becomes possibility.By virtual reality technology in conjunction with computer simulation technology, a lot of problems in vehicle simulation driving can be solved.Have the following advantages: effectively can improve system frame per second does not affect real-time, and the vehicle drive (keep straight on, turn, reversing, and above-mentioned several mixing are driven) under various operating mode can be realized.

Compare existing method, combined by computer programming with dimensional Modeling Technology, achieve the emulation of this rearview mirror, this is also the invention part of this patent.Compare, because stereo display is on rearview mirror, do not take main perspective space, i.e. driver visual angle; Size and shape is not had to limit to rearview mirror itself yet; Solid is presented on vehicle intuitively, both improves verisimilitude, also meets maneuverability.

Accompanying drawing explanation

Fig. 1 is method flow diagram of the present invention;

Fig. 2 and Fig. 3 is rearview mirror texture coordinate flow path switch figure of the present invention;

Fig. 4 and Fig. 5 is practical function figure of the present invention;

Fig. 6 is operation frame per second part design sketch of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is further described.

As shown in Figure 1 to Figure 3, a kind of rearview mirror emulation mode for vehicle simulation control loop, rearview mirror image adopts texture phase, realizing rearview mirror effect, specifically comprising the following steps by dynamically replacing texture in real time:

1), obtain vehicle drive time scene coordinate, utilize vehicle dynamic model obtain vehicle at three-dimensional system of coordinate x, the coordinate in y, z, and running attitude three-dimensional perspective α, beta, gamma, arranges simulation step length T; The basic exercise of vehicle can be divided into straight line and turning: controlled vehicle can carry out the driving under any operating mode in a program, and comprising advances keeps straight on, and turns to and drives and brake and reversing; By setting up vehicle dynamic model to realize,

1a, straight line model adopt Euler method emulation to obtain instantaneous velocity and the coordinate of vehicle; Suppose that the acceleration of vehicle remains unchanged in a simulation step length T, then the travel speed change discrete model of vehicle is:

$v(t+1)=v\left(t\right)+a\left(t\right)T=v\left(t\right)+\frac{T}{\mathrm{\δ}\·m}[F_t\left(t\right)-F_b\left(t\right)-F_f\left(t\right)-F_i\left(t\right)-F_w\left(t\right)]$

Wherein, v (t+1), v (t) is for vehicle is at the instantaneous velocity of t+1, t; T is simulation step length, and this emulation T gets 0.05s; δ is vehicle rotary quality coefficient; M is motor vehicle equipment quality; F _tfor Automobile drive power; F _bfor automobile acceleration resistance; F _ffor automobile resistance to rolling; F _ifor automobile grade resistance; F _wfor air resistance of automobile;

Just the concrete coordinate of t+1 moment vehicle can be obtained according to the algebraic manipulation of t vehicle coordinate and speed;

When 1b, vehicle occur to turn, the coordinate of the angle utilizing steering angle θ to obtain turning and the particular location residing for vehicle; Suppose that certain moment automobile driving speed is v (t), front wheel angle rotates δ ' angle, then have:

$\frac{{\mathrm{\ω}}_r}{{\mathrm{\δ}}^{,}}=\frac{v\left(t\right)/L}{1+\mathrm{Kv}{\left(t\right)}^2}$

K is stability factor; L is vehicle wheel base; ω _rfor stable state yaw velocity;

After elapsed time dt, automobile turns over d θ on inceptive direction, then motor turning mathematical model is:

$\frac{\mathrm{d\θ}}{\mathrm{dt}}={\mathrm{\ω}}_r=\frac{v\left(t\right)L}{1+\mathrm{Kv}{\left(t\right)}^2}\·{\mathrm{\δ}}^{,}$

Again arrange:

$\mathrm{d\θ}=\frac{v\left(t\right)/L}{1+\mathrm{Kv}{\left(t\right)}^2}\·{\mathrm{\δ}}^{,}\·\mathrm{dt}$

Just the coordinate after turn inside diameter can be calculated by angle θ;

1c, when vehicle is in pitching, yaw, side direction, Full Vehicle Dynamics model is utilized to obtain running attitude three-dimensional perspective α, beta, gamma;

Rearview mirror emulation must change according to vehicle-state in real time, and when namely during riding manipulation, vehicle is driven, rearview mirror must accomplish consecutive variations; During emergency brake of vehicle, rearview mirror scene must be static, and picture can not be had to be detained; Adopt rearview mirror rotation and dynamic texture to replace to realize:

2), utilize rearview mirror relative to the inactive of vehicle body, obtain rearview mirror camera coordinates, wherein rearview mirror camera is rotatable, is convenient to the scene catching rear view of vehicle; Arrange rotation matrix, in conjunction with coordinate and the running attitude three-dimensional perspective α of vehicle location, beta, gamma, adjusts rearview mirror camera;

With vehicle body direction for x-axis, horizontal vertical is y-axis in vehicle body direction, and system vertical is that z-axis sets up three-dimensional cartesian coordinate system in direction, ground; If earth axes XYZ is that { A}, rearview mirror camera coordinates system xyz (or vehicle body coordinate system) are { B}, so rearview mirror camera coordinates system { any point P in B} ^bat earth axes { the coordinate P in A} ^acan be calculated by following relation:

$M(z,\mathrm{\α})=\left[\begin{array}{ccc}\cos \mathrm{\α}& -\sin \mathrm{\α}& 0\\ \sin \mathrm{\α}& \cos \mathrm{\α}& 0\\ 0& 0& 1\end{array}\right]$

$M(y,\mathrm{\β})=\left[\begin{array}{ccc}\cos \mathrm{\β}& 0& \sin \mathrm{\β}\\ 0& 1& 0\\ -\sin \mathrm{\β}& 0& \cos \mathrm{\β}\end{array}\right]$

$M(x,\mathrm{\γ})=\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\γ}& -\sin \mathrm{\γ}\\ 0& \sin \mathrm{\γ}& \cos \mathrm{\γ}\end{array}\right]$

Wherein M (z, α) is for rearview mirror camera is around the rotation matrix at z-axis rotation alpha angle, and M (y, β) to rotate the rotation matrix at β angle for camera around y-axis, and M (x, γ) to rotate the rotation matrix at γ angle for camera around x-axis; When vehicle pose changes, camera also synchronously makes corresponding change, connects successively after calculating the coordinate on backsight minute surface 4 summits.

3), as shown in Figure 3, scene is read in frame buffer and creates rearview mirror texture, be roughly rectangle in conjunction with actual rearview mirror shape, set up a rectangle initial texture and bound, before binding, need its memory value to empty, definition initial texture is true value, arrange texture size be the integer power of 2 and ensure that texture size and rearview mirror size match, can reading speed be accelerated like this, and initial texture is set to dynamically, when vehicle movement, the rearview mirror texture of establishment is replaced in real time;

4), as shown in Figure 2, newly-generated texture carried out intercepting and changes, the coordinate figure on rearview mirror four summits being carried out algebraic manipulation and obtains rearview mirror texture size; In order to rearview mirror texture can be allowed correctly to show rearview mirror scene, and meet real vision, the vision of people should be that nearly person is large, and farther is little, and by arranging view frustums and carrying out projective transformation, arrange projective transformation matrix, projective transformation matrix is as follows:

$M^P=\left[\begin{array}{cccc}\frac{2n}{r-l}& 0& -\frac{r+l}{r-l}& 0\\ 0& \frac{2n}{t-b}& -\frac{t+b}{t-b}& 0\\ 0& 0& \frac{f}{f-n}& -\frac{\mathrm{fn}}{f-n}\\ 0& 0& 1& 0\end{array}\right]$

T, b, l, r are the vertical range of backsight minute surface to top, upper and lower, left and right; N is the distance of viewpoint to view frustums hither plane; F is the distance of viewpoint to view frustums far plane;

Projective transformation matrix and rotation matrix premultiplication have just been carried out projective transformation;

5), increase conversion between rearview mirror texture coordinate and screen coordinate, ensure that the texture that generates and actual rearview mirror scene match, the conversion between rearview mirror texture coordinate and screen coordinate in the following way:

$A_x=B_x\×\frac{\mathrm{width}}{2}+\frac{\mathrm{width}}{2}$

$A_y=\frac{\mathrm{height}}{2}-B_y\×\frac{\mathrm{height}}{2}$

Wherein, A _xfor the lateral coordinates of texture coordinate, A _yfor the longitudinal coordinate of texture coordinate, B _x, B _ybe respectively screen coordinate lateral coordinates and longitudinal coordinate, Width is the length of rearview mirror model, and Height is the wide of rearview mirror model.

6), by texture coordinate be mapped on rearview mirror model, finally play up whole scene; In order to prevent the phenomenon of the rearview mirror image retention that vehicle mutation movement produces, pointer function head it off is set; Create the pointer function that is pointed to rearview mirror, by binded texture with the address mark of a definition, and by the initial texture of pointed, a R function is encapsulated as with the whole process of replacing texture in real time, when vehicle location coordinate changes, new texture is assigned with the address of new storage, original address that old texture still retains, pointer will point to new address, makes rearview mirror camera change like this and changes synchronous realization with vehicle movement.

By described above, when searching out vehicle mirrors model and meeting related request, program judges and maps, otherwise continue repeat step 1)-step 6) and action.

Vision simulation refresh rate can not lower than 24hz, and whole emulation does not affect main line process, does not namely affect real-time; By pointed initial texture, and the whole process of replacing in real time texture is encapsulated as a R function, realizes by bar R function repeatedly the object that cycle alternation exports rearview mirror effect, simultaneously also not influential system frame per second.

By pointed initial texture, and the whole process of replacing in real time texture is encapsulated as a R function, achieves by this function of bar repeatedly the object that cycle alternation exports rearview mirror effect.

The present invention realizes by PC or driving simulation system.To the minimalist configuration requirement of computer be: Windows XP/2003,1G internal memory, video card Intel 3000 or more, VC++6.0 or more.The allocation of computer of this this program of commissioning test is as follows: CPU 2430M 2.4GHz, storer 2G, video card 2G Intel 3000, operating system Windows XP SP3, development platform Visual Studio.NET2003, simulated environment is Vega Prime 2.2 modeling software is Multigen Creator 3.2.Vehicle related parameters is as follows: vehicle mass m=1400kg, wheelbase L=2.46m, final driver ratio i _m=4.31,1 ~ 5 gear ratio of gear is respectively 3.267,1.769,1.147,0.872,0.679, and the initial speed of a motor vehicle is 25m/s, simulation step length T=0.05s.

Concrete operations comprise the following steps:

1) check PC operating system and associated software platforms, confirm to have installed MicrosoftVisual Studio.NET and the renewal of relevant VC++ assembly.

2) scene initialization: initial vehicle position is set, display window size, and relevant road scene;

3) double-click exe program or enter Visual Studio interface, click and run, waiting system can enter master routine picture after debugging about 1-3 second;

4) maneuver vehicle carries out vehicle virtual driving, can see rearview mirror effect comparatively clearly in left side.

Program needs to call VC++ when running, and after entering master routine interface, can see dynamic reversing mirror effect comparatively clearly by steering vehicle in vehicle left side.And rearview mirror imaging and actual driving situation match when running.Preliminary proof the present invention has certain ageing and feasibility, also reaches expection object.By setting up whole vehicle kinetic model at Matlab, become C Plus Plus to be compiled in Visual Studio the m integrating documents of this model, make calling program can motion capture to three-dimensional vehicle coordinate, comprise the coordinate of rearview mirror.

When program is run, main thread is as follows:

If Fig. 4 to Fig. 6 is simulated effect figure, rearview mirror emulation mode for vehicle simulation control loop provided by the invention, rearview mirror emulation changes according to vehicle-state in real time, create the pointer function that is pointed to rearview mirror, when vehicle location coordinate changes, the address stored also changes, and rearview mirror camera is changed and changes synchronous realization with vehicle movement.Whole emulation does not affect real-time; By creating dynamic texture, and being mapped on rearview mirror model, utilizing frame buffer technology draw simultaneously and discharge texture, improve the output of frame rate preferably.The stereo display of rearview mirror effect is on vehicle mirrors model; Rearview mirror emulation does not take main perspective, i.e. driver visual angle; Size and shape is not had to limit to rearview mirror itself yet; Solid is presented on vehicle intuitively, and rearview mirror can emulate in the driving under controlled vehicle in a program any operating mode.

The present invention has the verisimilitude of height and higher commercial value.This emulation mode also can be used in various driving game, especially vehicle drive game.

The above is only the preferred embodiment of the present invention; be noted that for those skilled in the art; under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (7)

1. for a rearview mirror emulation mode for vehicle simulation control loop, rearview mirror image adopts texture phase, realizing rearview mirror effect, specifically comprising the following steps by dynamically replacing texture in real time:

1), obtain vehicle drive time scene coordinate, utilize vehicle dynamic model obtain vehicle at three-dimensional system of coordinate x, the coordinate in y, z, and running attitude three-dimensional perspective α, beta, gamma, arranges simulation step length T; The basic exercise of vehicle can be divided into straight line and turning: controlled vehicle can carry out the driving under any operating mode in a program, and comprising advances keeps straight on, and turns to and drives and brake and reversing, by setting up vehicle dynamic model to realize;

2), utilize rearview mirror relative to the inactive of vehicle body, obtain rearview mirror camera coordinates, wherein rearview mirror camera is rotatable, is convenient to the scene catching rear view of vehicle; Arrange rotation matrix, in conjunction with coordinate and the running attitude three-dimensional perspective α of vehicle location, beta, gamma, adjusts rearview mirror camera;

3), scene read in frame buffer and create rearview mirror texture, rectangle is roughly in conjunction with actual rearview mirror shape, set up a rectangle initial texture and bound, its memory value is needed to empty before binding, definition initial texture is true value, and initial texture is set to dynamically, when vehicle movement, the rearview mirror texture of establishment is replaced in real time;

4), by newly-generated texture undertaken intercepting and change, the coordinate figure on rearview mirror four summits being carried out algebraic manipulation and obtains rearview mirror texture size; In order to rearview mirror texture can be allowed correctly to show rearview mirror scene, and meet real vision, the vision of people should be that nearly person is large, farther is little, by arranging view frustums and carrying out projective transformation, projective transformation matrix is set, projective transformation matrix and rotation matrix premultiplication have just been carried out projective transformation;

5) conversion, between increase rearview mirror texture coordinate and screen coordinate, ensures that the texture of generation and actual rearview mirror scene match,

6), by texture coordinate be mapped on rearview mirror model, finally play up whole scene; In order to prevent the phenomenon of the rearview mirror image retention that vehicle mutation movement produces, pointer function head it off is set; By the initial texture of pointed, and the whole process of replacing in real time texture is encapsulated as a R function, achieves by this function of bar repeatedly the object that cycle alternation exports rearview mirror effect.

2. a kind of rearview mirror emulation mode for vehicle simulation control loop according to claim 1, it is characterized in that: step 1) in " controlled vehicle can carry out the driving under any operating mode in a program; comprising advance keep straight on; turn to drive and brake and reversing, by setting up vehicle dynamic model to realize " refer to:

1a), straight line model adopts Euler method emulation to obtain instantaneous velocity and the coordinate of vehicle; Suppose that the acceleration of vehicle remains unchanged in a simulation step length T, then the travel speed change discrete model of vehicle is:

$v(t+1)=v\left(t\right)+a\left(t\right)T=v\left(t\right)+\frac{T}{\mathrm{\δ}\·m}[F_t\left(t\right)-F_b\left(t\right)-F_f\left(t\right)-F_i\left(t\right)-F_w\left(t\right)]$

Wherein, v (t+1), v (t) is for vehicle is at the instantaneous velocity of t+1, t; T is simulation step length; δ is vehicle rotary quality coefficient; M is motor vehicle equipment quality; F _tfor Automobile drive power; F _bfor automobile acceleration resistance; F _ffor automobile resistance to rolling; F _ifor automobile grade resistance; F _wfor air resistance of automobile;

Just the concrete coordinate of t+1 moment vehicle can be obtained according to the algebraic manipulation of t vehicle coordinate and speed;

1b), vehicle is when occurring to turn, and utilizes steering angle θ to obtain the coordinate of angle and the particular location residing for vehicle of turning; Suppose that certain moment automobile driving speed is v (t), front wheel angle rotates δ ' angle, then have:

$\frac{{\mathrm{\ω}}_r}{{\mathrm{\δ}}^{\′}}=\frac{v\left(t\right)/L}{1+\mathrm{Kv}{\left(t\right)}^2}$

K is stability factor; L is vehicle wheel base; ω _rfor stable state yaw velocity;

After elapsed time dt, automobile turns over d θ on inceptive direction, then motor turning mathematical model is:

$\frac{\mathrm{d\θ}}{\mathrm{dt}}={\mathrm{\ω}}_r=\frac{v\left(t\right)L}{1+\mathrm{Kv}{\left(t\right)}^2}\·{\mathrm{\δ}}^{\′}$

Again arrange:

$\mathrm{d\θ}=\frac{v\left(t\right)/L}{1+\mathrm{Kv}{\left(t\right)}^2}\·{\mathrm{\δ}}^{\′}\·\mathrm{dt}$

Just the coordinate after turn inside diameter can be calculated by angle θ.

3. a kind of rearview mirror emulation mode for vehicle simulation control loop according to claim 1, it is characterized in that: step 2) in " rotation matrix is set; in conjunction with coordinate and the running attitude three-dimensional perspective α of vehicle location; β; γ, adjusts rearview mirror camera " specifically refer to:

With vehicle body direction for x-axis, horizontal vertical is y-axis in vehicle body direction, and system vertical is that z-axis sets up three-dimensional cartesian coordinate system in direction, ground; If earth axes XYZ is that { A}, rearview mirror camera coordinates system xyz (or vehicle body coordinate system) are { B}, so rearview mirror camera coordinates system { any point P in B} ^bat earth axes { the coordinate P in A} ^acan be calculated by following relation:

$M(z,\mathrm{\α})=\left[\begin{array}{ccc}\cos \mathrm{\α}& -\sin \mathrm{\α}& 0\\ \sin \mathrm{\α}& \cos \mathrm{\α}& 0\\ 0& 0& 1\end{array}\right]$

$M(y,\mathrm{\β})=\left[\begin{array}{ccc}\cos \mathrm{\β}& 0& \sin \mathrm{\β}\\ 0& 1& 0\\ -\sin \mathrm{\β}& 0& \cos \mathrm{\β}\end{array}\right]$

$M(x,\mathrm{\γ})=\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\γ}& -\sin \mathrm{\γ}\\ 0& \sin \mathrm{\γ}& \cos \mathrm{\γ}\end{array}\right]$

Wherein M (z, α) is for rearview mirror camera is around the rotation matrix at z-axis rotation alpha angle, and M (y, β) to rotate the rotation matrix at β angle for camera around y-axis, and M (x, γ) to rotate the rotation matrix at γ angle for camera around x-axis; When vehicle pose changes, camera also synchronously makes corresponding change, connects successively after calculating the coordinate on backsight minute surface 4 summits.

4. a kind of rearview mirror emulation mode for vehicle simulation control loop according to claim 1, is characterized in that: step 4) in projective transformation matrix as follows:

$M^P=\left[\begin{array}{cccc}\frac{2n}{r-l}& 0& -\frac{r+l}{r-l}& 0\\ 0& \frac{2n}{t-b}& -\frac{t+b}{t-b}& 0\\ 0& 0& \frac{f}{f-n}& -\frac{\mathrm{fn}}{f-n}\\ 0& 0& 1& 0\end{array}\right]$

T, b, l, r are the vertical range of backsight minute surface to top, upper and lower, left and right; N is the distance of viewpoint to view frustums hither plane; F is the distance of viewpoint to view frustums far plane.

5. a kind of rearview mirror emulation mode for vehicle simulation control loop according to claim 1, is characterized in that: step 5) in conversion between rearview mirror texture coordinate and screen coordinate in the following way:

$A_x=B_x\×\frac{\mathrm{width}}{2}+\frac{\mathrm{width}}{2}$

$A_y=\frac{\mathrm{height}}{2}-B_y\×\frac{\mathrm{height}}{2}$

Wherein, A _xfor the lateral coordinates of texture coordinate, A _yfor the longitudinal coordinate of texture coordinate, B _x, B _ybe respectively screen coordinate lateral coordinates and longitudinal coordinate, Width is the length of rearview mirror model, and Height is the wide of rearview mirror model.

6. a kind of rearview mirror emulation mode for vehicle simulation control loop according to claim 1, is characterized in that: the stereo display of rearview mirror effect is on vehicle mirrors model; The emulation of this rearview mirror does not take main perspective, i.e. driver visual angle; When searching out vehicle mirrors model and meeting related request, program judges and maps, otherwise continue repeat step 1)-step 6) and action.

7. a kind of rearview mirror emulation mode for vehicle simulation control loop according to claim 1, is characterized in that: vision simulation refresh rate can not lower than 24hz, and whole emulation does not affect main line process, does not namely affect real-time; By pointed initial texture, and the whole process of replacing in real time texture is encapsulated as a R function, realizes by bar R function repeatedly the object that cycle alternation exports rearview mirror effect, simultaneously also not influential system frame per second.