CN103413473B - Driving simulation system of underground mine hinged trolley - Google Patents

Abstract

The invention provides a driving simulation system of an underground mine hinged trolley. The driving simulation system comprises an underground mine hinged trolley movement control model, a visual data model, a scene simulation engine, a driving assisting unit, a sound simulation engine, a display terminal, an audio output terminal and a virtual driving unit. The underground driving process of the hinged trolley can be truly simulated through the establishment of the models, a driver carries out driving simulation through the virtual driving unit, an underground roadway environment and the underground mine hinged trolley can be simulated, and a good platform is provided for the intelligent control technology of the underground mine hinged trolley. According to the driving simulation system of the underground mine hinged trolley, a simulation driving operational platform is designed according to a true trolley, the driver can conveniently carry out driving operation, and the feeling of the driver can be true. The cost for carrying out testing through the true trolley is greatly reduced, and damage to the driver in the underground dangerous driving environment is effectively reduced.

Description

A driving simulation system for an articulated vehicle used in underground mines

technical field

The invention relates to a driving simulation system, in particular to a driving simulation system for an articulated vehicle used in underground mines.

Background technique

In the underground mining industry, the climbing ability and transportation efficiency of trackless transport vehicles are much higher than those of rail transport vehicles. With the progress of my country's mining industry, the use of trackless transport vehicles has become the development trend of the underground mining industry, improving the intelligence of underground vehicles The level of control is an important technical development direction to further improve the transportation efficiency of mine vehicles. However, the current research on vehicle intelligent driving technology generally requires the modification or configuration of real vehicles and tests on roads or specific environments. The real factor is the cost of real vehicle experiments. High, long cycle and high risk, and the experimental process is not reproducible. Using vehicle driving simulation to carry out intelligent research on vehicles in virtual scenes is a new research direction. In the virtual environment, the driving behavior and related factors of vehicles are rehearsed to ensure that vehicles can drive intelligently and safely.

In the prior art, there are many driving simulation systems. Document 1 ["Design and Implementation of Driving Simulation System Based on OGRE and ODE"] (Traffic Information and Safety, 2006, 1 (24): 101) reported a driving simulation system based on The driving simulation system design method of OGRE and ODE uses OGRE to render the driving environment of the vehicle, uses ODE as a tool combined with the vehicle dynamics model to simulate vehicle movement, and realizes an interactive driving simulation system that can be operated through peripheral input devices. Driving training for car drivers. Chinese utility model patent ZL201220293043.X discloses a new type of simulated driving system, which controls the simulated vehicle driving through the driving controller, makes the driver feel the road conditions through the dynamic platform, and presents the simulated driving environment through the simulated video glasses. The system mainly uses in the training of vehicle drivers.

The above-mentioned existing driving simulation system is characterized in that it can only simulate the vehicle driving environment in the ground environment, and cannot simulate the roadway environment in which underground mining vehicles work; Underground mining vehicles; it can only be used for driver training and training, and cannot be added to the assisted driving unit, and does not have the function of verifying autonomous driving strategies.

Contents of the invention

The invention relates to a driving simulation system for an articulated car for underground mines, which is provided with an auxiliary driving unit, capable of simulating the environment of an underground roadway and the driving simulation system for an articulated car for underground mines, and provides a good platform for the intelligent control technology of an articulated car for underground mines . It includes:

(1) The virtual driving unit includes virtual driving console, steering wheel, operating handle, accelerator pedal, brake pedal, display screen and audio, etc. These devices constitute the control mechanism of the system.

(2) Underground articulated vehicle motion control model, visualized data model, visual simulation engine, auxiliary driving unit, underground articulated vehicle sound simulation, and virtual driving unit. The establishment of these models can truly simulate the driving process of an articulated vehicle underground. Driving simulation is carried out through the external virtual driving unit.

(3) The dynamics model of the vehicle is a key part of the system. According to the characteristics of the articulated vehicle, a three-degree-of-freedom dynamics and kinematics model is established. The dynamic model directly uses the data input by the equipment, and obtains the engine speed, position and attitude of the vehicle through real-time calculation.

(4) Visual data models include 3D models of articulated vehicles, 3D models of underground roadways and traffic signs, etc.

(5) Visual simulation engine, using computer graphics and image technology to generate the underground virtual environment seen by the driver during vehicle driving, such as roadways, traffic signs and lights.

(6) Assisted driving unit, which can carry out intelligent assisted driving of underground articulated vehicles in a virtual environment, and add virtual laser radar to the system according to the working principle of real laser radar through ray projection technology, and measure vehicles and roadways through virtual laser radar distance from walls and obstacles. Through the corresponding assisted driving strategy, the system will issue a warning when the vehicle is driving too close to the roadway wall or there are foreign objects in the roadway and other dangerous driving situations.

(7) Underground sound simulation engine, which produces sounds with different effects such as engine sound, noise of operating machinery in the roadway, etc.

This system uses an open source sound engine. In order to make the sound effect more realistic, the system uses stereo sound effect.

In this system, the simplified vehicle dynamics and motion control model is used, and discretization is performed, and the relevant calculation of vehicle motion control is performed during the CPU idle time between two frames of computer graphics rendering. The motion control model is established by the following steps:

Set the central hinge point of the mine car as point H, the middle point of the front axle is Pf(x1,y1), the distance between this point and the central hinge point H is l1, and the vehicle speed is vf; the middle point of the rear axle is Pr(x2,y2) point, the distance between this point and the central hinge point is l2, the vehicle speed is vr, the yaw rate of the front body is ω1, the turning radius is r1, the yaw rate of the rear body is ω2, the turning radius is r2, the heading of the front body angle is θ1, the heading angle of the rear body is θ2, and the articulation angle is γ. Let the midpoint pose state vector S _t =[x ₁ (t)y ₁ (t)θ ₁ ( ^t )] of the front axle The position and heading angle of the car body at time t, then the front axle pose state vector S _{t+1 at time t+1} =[x ₁ (t+1)y ₁ (t+1)θ ₁ t+1)] ^T , expressed as

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}& \frac{<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}\end{array}\right]\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\\ {\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\end{array}\right]<span\; class="notranslate">\; ,</span>$

The speed of the car body before the current simulation moment is vf(t), and the rotation rate of the joint angle is The time interval from the last simulation to this simulation is Ts, and the angular velocity of the front car body is obtained as

In the formula — Articulation angle rotation rate

$\stackrel{\&Center\; Dot;}{\mathrm{\&gamma;}}t=\frac{\mathrm{\&gamma;t}-\mathrm{\&gamma;t}-1}{T_{\mathrm{the\; s}}}$ ,

The heading angle of the front body is equal to the heading angle at the previous moment plus the increment of this simulation

θ ₁ t=θ ₁ t-1+ω ₁ (t)T _s ,

The heading angle of the rear body is equal to the sum of the heading angle of the front body and the articulation angle

θ ₂ t = θ ₁ + γ t,

The world coordinates of the midpoint of the front axle of the vehicle at time t are obtained from the driving speed and heading angle of the front vehicle body as follows:

$\left\{\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ]</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ]</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\end{array}\right.$

According to the geometric relationship, the coordinates of the midpoint of the bridge after time t are obtained

$\left\{\begin{array}{cccc}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}& <span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}& <span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\end{array}\right.$

The lifting of the cargo box is at a uniform speed. The value of ω3 is obtained from the control parameters of the cargo box, so as to obtain the lifting angle θ3. When the value of the control input C is 0, the cargo box is lowered, and when the value of C is 1, the cargo box is lifted. , the lifting angle of the cargo box ranges from 0 to 60 degrees, and the lifting or lowering speed of the cargo box is:

${\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\frac{\mathrm{<span\; class="notranslate">\; 60</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}}& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\\ \frac{\mathrm{<span\; class="notranslate">\; 60</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>\end{array}\right.<span\; class="notranslate">\; ,</span>$

The lifting angle of the container at time t is:

${\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}& <span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>\end{array}\right.$

Compared with the prior art, the present invention has the beneficial effects of

(1) Compared with the real vehicle, the present invention designs a simulated driving console, which is convenient for the driver to perform driving operations and makes the driver feel more real.

(2) The present invention establishes vehicle kinematics and dynamics models for the articulated vehicle used in underground mines, which can truly simulate the driving of the articulated vehicle body.

(3) The present invention can truly simulate the underground roadway environment, and provides environmental support for driving simulation of underground vehicles.

(4) The invention has an auxiliary driving unit, which can simulate the driving of intelligent vehicles, and provides a good platform for the research on intelligent control technology of underground mining vehicles.

(5) The present invention can greatly reduce the cost of using a real car to conduct experiments, and effectively reduce the harm to the driver in an underground dangerous driving environment.

Description of drawings

Figure 1 is a schematic diagram of a virtual driving unit.

Figure 2 is a steering diagram of the articulated car body.

Figure 3 is a data interaction diagram.

Figure 4 Vehicle coordinate system diagram.

Figure 5 is a three-dimensional model diagram of the vehicle.

Figure 6 is the overall structure diagram of the roadway.

Figure 7 is the interior map of the roadway.

Fig. 8 is a flow chart of starting the graphics simulation engine.

Fig. 9 is a scene diagram of the driving simulation system.

Figure 10 is a cutaway view of the camera.

Fig. 11 is a first-person and third-person view of the driving simulation system.

Figure 12 is a structural diagram of the frame listener class.

Figure 13 shows the scanning range of lidar.

Figure 14 is a virtual lidar test diagram.

Figure 15 is a scan diagram of the left side of the vehicle approaching the roadway.

Fig. 16 is a diagram of the scanning data of the virtual lidar scanned by the vehicle close to the left side of the roadway.

Fig. 17 is a diagram of the scanning data of the virtual lidar scanned by the vehicle close to the right side of the roadway.

Figure 18 Tips for dangerous driving behavior.

detailed description

1) The specific implementation of the present invention will be further described in detail below in conjunction with the accompanying drawings and examples.

2) The driving simulation system of articulated vehicles for underground mining includes motion control models of articulated vehicles for underground mining, visual data models, visual simulation engines, auxiliary driving units, sound simulation engines, display terminals, audio output terminals and virtual driving units. The establishment of the system can truly simulate the driving process of the articulated vehicle underground, and the driver can simulate driving through the virtual driving unit.

3) The hardware equipment of the local mining car driving simulation system consists of a virtual driving console, a high-performance computer, a display terminal and an audio output terminal.

4) The virtual driving console includes a display terminal bracket and a driving console. The display terminal bracket is used to support three display screens. The driver can fully experience the graphical driving environment of the underground roadway and the driving state of the articulated vehicle through the three display screens. . The driving platform is designed and manufactured according to the structural size of the real vehicle, including the driver's seat, steering wheel, operating handle, accelerator pedal and brake pedal, on which the driver can perform the same driving operations as the real vehicle, as shown in Figure 1.

5) In the underground mine car driving simulation system, the steering wheel is equipped with a rotary encoder, which outputs pulse signals to record the angle it has turned; the accelerator pedal and brake pedal output analog voltage signals, and output the corresponding value of voltage according to the stroke of the pedals signal to control the acceleration and deceleration; the work handle outputs a digital voltage signal to control the lifting and lowering of the articulated vehicle container. These signals are collected by the PCI-IO card of the host computer and transmitted to the motion control model. The motion control model calculates the next position and attitude data of the vehicle according to the current vehicle state and input data, and transmits these data to the visual simulation system. The rendering and output are completed by the visual simulation system, and the driver can intuitively feel the driving state of the vehicle through the display terminal and audio output terminal.

6) High-performance computers are required to be able to quickly process 3D graphics and dynamic calculations. The computer graphics card supports three-screen display to achieve the purpose of all-round display. sound.

7) The vehicle dynamics and kinematics models in the driving simulation system cannot directly use the form of differential equations, because the computer will take up a lot of CPU time to solve the differential equations, which will affect the response speed of the system. Therefore, the simplified vehicle dynamics and kinematics model is used in this system, and it is discretized, and the relevant calculation of vehicle motion control is performed during the CPU idle time between two frames of computer graphics rendering.

8) In the underground mine car driving simulation system, the motion control model directly receives the data xin of the control mechanism collected by the system, and outputs the corresponding kinematic parameters xf, xr, and xd to the visual simulation system through the calculation of the motion control model. See Figure 2 for system data flow.

9) The input control data of the control mechanism used in this system can be expressed as $x_{\mathrm{in}}={[{\mathrm{\&phi;}}_a,{\mathrm{\&phi;}}_b,\mathrm{\&theta;},\stackrel{\&Center\; Dot;}{\mathrm{\&theta;}},C,G]}^T,$

10) In the formula, φ _a , φ _b —— accelerator pedal and brake pedal position

11) θ, ——Steering wheel angle and turning rate

12) C——Container lifting control, C=0, 1

13) G——Gear, G=1, 2, 3

14) The coordinate system in the graphics engine is different from the SAE standard coordinate system. The coordinate system in OGRE takes the screen as a reference. The horizontal direction to the right is the positive direction of the X-axis, the vertical direction is the positive direction of the Y-axis, and the vertical direction to the outside of the screen is the Z-axis For the positive direction, see Figure 3.

15) The model coordinate system is established based on the coordinate system in OGRE. The driving simulation system adopts a three-degree-of-freedom model, which does not consider the vehicle's roll and pitch movements, only yaw rotation, and assumes that the vehicle has no translation in the vertical direction.

16) Divide the model into several parts, such as the front body, rear frame, cargo box and wheels, and process them separately. The kinematic control parameters xf and xr of the front and rear frames can be expressed as $x_f={[{\mathrm{\&theta;}}_1,{\mathrm{\&omega;}}_1,{\stackrel{\&Center\; Dot;}{\mathrm{\&omega;}}}_1,v_{\mathrm{fx}},v_{\mathrm{fz}},a_{\mathrm{fx}},a_{\mathrm{fz}}]}^T,x_r={[{\mathrm{\&theta;}}_2,{\mathrm{\&omega;}}_2,{\stackrel{\&Center\; Dot;}{\mathrm{\&omega;}}}_2{v}_{\mathrm{r\; x}},v_{\mathrm{rz}},a_{\mathrm{r\; x}},a_{\mathrm{rz}}]}^T,$

17) In the formula, θ ₁ and θ ₂ ——the yaw angles of the front body and the rear body

18) ω ₁ , ω ₂ ——the yaw rate of the front body and the rear body

19) ——The yaw angular acceleration of the front body and the rear body

20) v _fx , v _fz —— the lateral and longitudinal velocity of the midpoint of the front axle of the front body

21) v _rx , v _rz —— the lateral and longitudinal velocity of the midpoint of the rear axle of the rear body

22) a _fx , a _fz - lateral and longitudinal accelerations at the midpoint of the front axle of the front body

23) a _rx , a _rz —— the lateral and longitudinal speeds of the midpoint of the rear axle of the rear body

24) The cargo box and the rear frame are connected by hinges, so the kinematic parameters of the cargo box are basically the same as those of the rear frame, except that the angular freedom around the Z axis is added, then the kinematic control parameters of the cargo box are $x_d={[{\mathrm{\&theta;}}_2,{\mathrm{\&theta;}}_3,{\mathrm{\&omega;}}_2,{\mathrm{\&omega;}}_3,{\stackrel{\&Center\; Dot;}{\mathrm{\&omega;}}}_{2,}{v}_{\mathrm{r\; x}},v_{\mathrm{rz}},a_{\mathrm{rz}},a_{\mathrm{rz}}]}^T$

25) where θ ₃ , ω ₃ —— the lifting angle and angular velocity of the container

26) In the system, the rendering of 3D graphics consumes most of the CPU time, and the dynamic calculation should be performed between rendering two frames of images. In order to make the simulation effect as close as possible to reality and real-time, the dynamic characteristics of the articulated vehicle were simplified, and a nonlinear discretized three-degree-of-freedom (3-DOF) model was established in world coordinates.

27) The dynamic model of the articulated vehicle in this embodiment is established with a 35-ton electric drive articulated dump truck.

28) The mathematical model of the vehicle speed during driving is am=F _t -F _f -F _i -F _w

29) In the formula, m——whole vehicle mass

30) a——vehicle driving acceleration

31) Ft - vehicle driving force

32) Ff - vehicle rolling resistance

33) Fi - slope resistance

34) Fw - the air resistance of the vehicle

35) The maximum speed of the vehicle is designed to be 25Km/h, and the air resistance Fw can be ignored. Since the model of the vehicle on the two-dimensional plane is derived, the slope resistance Fi is ignored. The impact of the braking force Fb should also be considered during the running of the car. To sum up, the driving speed model of the car is ma=F _t -F _f -F _b

36) The engine model uses the cubic polynomial fitting method to obtain the relationship between the steady-state torque and the rotational speed as

37) M _e =a ₀ +a ₁ n _e +a ₂ n _e ² +a ₃ n _e ³

38) where ai——fitting coefficient, i=0, 1, 2, 3

39) Me - engine torque

40) ne - engine speed

41) The relationship between engine torque and traction force can be expressed as

42) In the formula, i ₀ ——Main transmission ratio

43) i _g —— transmission ratio

44) R _w - wheel radius

45) η _T —— mechanical efficiency of drive train

46) Assume that the relationship between the travel of the brake pedal and the braking force is linear

47) where φ _b ——brake pedal stroke; φ _{bmax ——brake} pedal maximum stroke

48) Fc - maximum braking force

49) Then the acceleration of the vehicle at time t can be obtained as

50) Assuming that the acceleration of the vehicle remains unchanged in the two simulations, the vehicle speed at time t can be obtained as

Vt=Vt-1+atT _s

51) In the formula, Ts——time difference between two simulation calculations

52) The kinematics model of the articulated car is established as follows, as shown in Figure 4, the central hinge point of the mine car is set as point H, the middle point of the front axle is Pf(x1, y1), the distance between this point and the central hinge point H is l1, the vehicle speed is vf; the middle point of the rear axle is Pr(x2,y2), the distance between this point and the central hinge point is l2, and the vehicle speed is vr.

53) The yaw angular velocity of the front body is ω1, the turning radius is r1, the yaw angular velocity of the rear body is ω2, and the turning radius is r2. The heading angle of the front body is θ1, the heading angle of the rear body is θ2, and the hinge angle is γ. Let the pose state vector S _t =[x ₁ (t)y ₁ (t)θ ₁ (t) ^T , represent the position and heading angle of the front vehicle body at time t. Then the front axle pose state vector S _t+1 =[x ₁ (t+1)y ₁ (t+1)θ ₁ (t+1)] ^r at time t+1 can be represented by a nonlinear discrete model for

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \frac{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}& \frac{<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&gamma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}\end{array}\right]\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\\ {\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\end{array}\right]<span\; class="notranslate">\; ,</span>$

54) The speed of the car body before the current simulation moment is vf(t), and the rotation rate of the joint angle is , the time interval from the last simulation to this simulation is Ts, the angular velocity of the front car body can be obtained as

55) where ——Rotation rate of hinge angle

56) $\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}t=\frac{\mathrm{\&gamma;t}-\mathrm{\&gamma;t}-1}{T_{\mathrm{the\; s}}}$

57) The heading angle of the front body is equal to the heading angle at the previous moment plus the increment of this simulation (θ ₁ t=θ ₁ ,t-1+ω ₁ (t)T _s ,

58) The heading angle of the rear body is equal to the sum of the heading angle of the front body and the articulation angle θ ₂ t=θ ₁ t+γt,

59) The world coordinates of the midpoint of the front axle of the vehicle at time t can be obtained from the driving speed and heading angle of the front car body as

$\left\{\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ]</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ]</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}\end{array}\right.<span\; class="notranslate">\; ,</span>$

60) According to the geometric relationship, the coordinates of the middle point of the bridge after time t can be obtained

$\left\{\begin{array}{cccc}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}& <span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}& <span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}& \mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}{\mathrm{<span\; class="notranslate">\; \&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\end{array}\right.$

61) The lifting of the container is considered to be at a constant speed, so the value of ω3 needs to be obtained from the control parameter xd of the container to obtain the lifting angle θ3. When the value of the control input C is 0, the container is lowered, and when the value of C is 1, the container is lifted. The lifting angle range of the cargo box is 0 to 60 degrees, the lifting time of the cargo box is Tu=10.5s, and the descending time of the cargo box is Td=11.2s, then the lifting or lowering speed of the cargo box is:

62) Then the lifting angle of the container at time t is:

63) After the motion control model of the articulated vehicle is built, start to build the visual data model.

64) The vehicle model in the embodiment is established by SolidWorks, the roadway model is established by Google SketchUp, the graphics engine is GORE, and the sound engine is FMOD.

65) In order to simplify the model and export the model at the same time, use the 3D model surface reduction tool Polygon Cruncher to simplify the model for better program operation efficiency.

66) In order to be able to flexibly control the underground mining vehicle, this paper splits the three-dimensional model of the vehicle into four parts: the front body, the rear frame, the cargo box and the wheels, and the four wheels share the same model. Since the model does not have any texture map information after importing, it is necessary to add corresponding map materials to the model in SketchUp, such as cockpit glass, car body yellow paint and tire materials. The three-dimensional model of the articulated vehicle is shown in Figure 5.

67) The 3D model of the roadway is directly modeled with SketchUp. When modeling, the roadway section is first drawn, and then the roadway model is established by path following stretching. After the model is established, the rock material is used as a map to cover the entire inner wall of the roadway. The model is shown in Figures 6 and 7.

68) After the visual data model is established, start to use the OGRE graphics engine for graphics rendering.

69) The graphics engine startup process is shown in Figure 8, which defines all the settings of the rendering system, including resolution, color depth, whether to display in full screen, whether to use DirectX or OPENGL for underlying rendering, and so on.

70) The next step is to create the specific rendering system, and then create the scene manager, which is responsible for managing the models in the scene. Create a viewpoint to complete the transformation of the vehicle's driving perspective, and realize driving from a first-person perspective and a third-person perspective. Create an input listener to monitor incoming data. Create a frame listener, add the frame listener to the root file, and then perform various operations and logic control through the rendering queue method of each frame.

71) The OGRE graphics engine manages all renderable objects in the scene in the form of a scene graph. OGRE manages the scene graph uniformly by the scene manager class.

72) Attachment 9 shows the scene graph structure of the driving simulation system. The scene manager is directly mounted on the root node of the OGRE system, and the scene manager is respectively mounted under the static object node, the front body node, and the rear frame nodes, container nodes, wheel nodes and cameras. Static entities such as signs and obstacles are mounted under the static object node; the front body node mounts the front body entity and front headlights; the rear frame node mounts the rear frame entity; the container node mounts the container entity; The node mounts the wheel entity.

73) The camera is also mounted on the scene manager as a special node. The main job of the camera is to intercept a part of the graphics in the virtual scene to complete the rendering. In addition to the orientation of the camera, there are two important parameters, the near interception distance and the far interception distance. The two distances respectively determine the distance between the near section and the far section from the observation point. A six-sided viewing volume is formed by two sections. That is to say, not all elements in the virtual scene will be rendered, but determined by the camera's view frustum (see Figure 10), and only the elements in the view frustum will be rendered.

74) OGRE uses the Frustum class to simulate the visual effect of the human eye. On the interface, according to the user's usage habits, it is convenient for the user to convert the model coordinates. In the internal implementation, the conversion between human vision and computer vision is completed through the matrix conversion of graphics. Mathematical conversion to achieve a better transition effect.

75) The motion control method of the driving simulator is completely in accordance with the control method of the actual vehicle. The camera observation point is bound to the position of the vehicle, so the movement phase of the operation camera viewpoint needs to be manipulated according to the real-time state of the vehicle. The motion control of the vehicle is based on the position and attitude results obtained by real-time calculations based on dynamics and kinematics models. The simulation in the computer is based on discrete time points, and the time interval between two cycles is very small, assuming that the force on the object does not change during this time. After the position and attitude of the vehicle is updated, the relevant data is obtained, and then the following effect of the camera is completed by updating the position and orientation parameters of the camera.

76) As shown in Figure 11, the vehicle needs to use the first-person perspective to operate during normal driving, that is, look forward from the driver's cab from the perspective of a normal driver, and when used as a third-party surveillance, it can use the third-person perspective to view Monitor the driving direction of the vehicle at the rear and upper direction outside the vehicle.

77) In order to realize the perspective following with the previous car body as the reference point, after each calculation of the dynamic model, start to calculate the following position of the camera.

78) The coordinates of the obtained front car body node are the geometric center of the model, so the position of the point where the camera should follow can be obtained by a fixed distance translation. According to the size of the model in this system, if the observation point is located in the cab, it needs to move 1 unit distance to the negative direction of the Z axis, 1.2 unit distance to the positive direction of the X axis, and 1.2 unit distance to the positive direction of the Y axis. In the first-person view mode, you can directly move forward a certain distance at the position of the observation point. Third-person perspective is similar to first-person perspective.

79) Dynamic calculation is integrated with OGRE. The OGRE system is provided to users in the form of a class library. Using OGRE requires programming according to actual needs. At the beginning of OGRE, the configuration file is first loaded, the resource path is set, and then the scene manager, camera and viewport are created respectively. Then register the frame listener in the main loop of OGRE, and the embodiment implements this function by inheriting the frame listener class from OGRE.

80) The frame listener provides methods for processing events before frame rendering (FrameStarted), frame rendering (FrameRenderingQueued) and frame rendering (FrameEnded). After calling the pre-rendering event processing method, OGRE starts to update all rendering targets. It is completed by the CPU. At this time, the CPU is not fully utilized, and the dynamics and kinematics calculations (DynamicSimulation) of the vehicle need to be completed by the CPU, so the calculations related to dynamics and kinematics are performed immediately after Run within the handler method of the frame renderer.

81) OGRE does not provide an interface for reading peripherals. This system uses OIS to read input data. First create an OIS device manager in OGRE's frame listener, and set OIS to non-buffered input mode. Afterwards, the input data is processed through UnbufferedInput and converted into the data format required for dynamic simulation. The frame listener of OGRE provides the frame event entity to store the time information related to the frame event, including the frame time interval. This data is the time interval to Ts used in dynamic calculation. Attached figure 12 shows the frame listener class structure.

82) The sound simulation engine is used to create sounds with different effects such as engine sound and operating machinery noise in the roadway. The sound playback needs to be triggered by corresponding events, and the 3D sound effect of FMOD is used in this system to realize the 3D effect of the sound, and the position of the sound source is updated through the event.

83) Assisted driving unit, which can carry out intelligent assisted driving of underground articulated vehicles in a virtual environment, and add virtual laser radar to the system according to the working principle of real laser radar through ray projection technology, and can measure vehicles and roadway walls through virtual laser radar and the distance of obstacles, see Figure 13. Through the corresponding assisted driving strategy, the system will issue a warning when the vehicle is too close to the roadway wall or there are foreign objects in the roadway when dangerous driving conditions occur.

84) Ray casting is to send a ray from a certain point in space to a set direction. When the ray intersects with an object in the scene, it returns the name of the object and the coordinates of the intersection point of the ray and the AABB bounding box of the object. Only the coordinates with the bounding box cannot meet the requirements, and the virtual lidar must be accurate enough to measure the intersection with the triangle surface of the model mesh. Therefore, it is necessary to extract the vertices and index data of the model, and then traverse all triangle faces and rays to see if there is an intersection point to obtain the nearest intersection point.

85) Using ray projection technology to simulate lidar, first use OGRE to create a ray projection, and set the starting point and projection direction of the ray. The starting point of the light is set at a positive translation of 3.2m from the midpoint of the front axle to the X-axis, as shown in the center of the sector in Figure 13. The light is projected on the XZ plane, and the direction is scanned from -5° to 185°. Each scan first judges whether there is an object intersecting with the ray, if there is an intersecting object, extract the vertex and vertex index data of the object, traverse all the facets whether intersecting with the ray, and find the nearest intersection point.

86) Figures 14 and 15 are the virtual lidar dynamic data acquisition renderings of the driving simulation system. The scanning accuracy of the virtual lidar is set at 1°, the scanning frequency is 25Hz, and the scanning range is from -5° to 185°, starting from the right side of the vehicle Scan to the left end, visualize the virtual laser, and draw a white line segment from the laser emission point to the detected intersection point.

87) Taking the data obtained from the experiment as the horizontal axis with the scanning angle and the vertical axis with the distance, you can get Figures 16 and 17. It can be seen from Figure 16 that the distance between -5° and 75° is small, so it can be judged that the vehicle is driving on the right. Figure 17 is the opposite of Figure 16, and the distance is between 110° and 185° Smaller, so it can be judged that the vehicle is driving on the left.

88) The auxiliary driving unit has a dangerous driving warning function. When the virtual lidar detects an obstacle with a distance less than 1.5m in any direction, the system will give a warning. As shown in Figure 18, when the vehicle is too close to the roadway on the right and the distance is less than 1.5m, the system will prompt the driver "Warning: the distance to the right is less than 1.5m" in the upper right corner. In the same situation, if the vehicle is too close to the roadway on the left and the distance is less than 1.5m, the system will prompt the driver "Warning: less than 1.5m to the left" in the upper right corner.

89) The above is only the preferred implementation mode of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principles of the present invention, several improvements and modifications can be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (4)

1. a driving analog system for [underground articulator, is characterized in that, this system comprises: [underground articulator Motion Controlling Model, visual data model, vision simulation engine, auxiliary driving unit, sound simulation engine, virtual driving unit;

Described auxiliary driving unit can carry out the auxiliary driving of intelligence of underground articulator in virtual environment, add virtual laser radar according to the principle of work of actual laser radar in systems in which by ray cast technology, the distance of vehicle and wall and barrier can be measured by virtual laser radar; Described virtual driving unit comprises virtual driving operator's console, bearing circle, operation handle, accelerator pedal, brake pedal, display screen and sound equipment; Wherein, [underground articulator Motion Controlling Model adopts following steps to set up:

If mine car central pivot point is set to H point, propons mid point is Pf (x1, y1), and the distance of propons mid point and central pivot point H is l1, and the speed of a motor vehicle is vf; Back axle mid point is Pr (x2, y2) point, the distance of back axle mid point and central pivot point is l2, and the speed of a motor vehicle is vr, front vehicle body yaw velocity is ω 1, turning radius is r1, and aftercarriage yaw velocity is ω 2, and turning radius is r2, the course angle of front vehicle body is θ 1, the course angle of aftercarriage is θ 2, and splice angle is γ, if propons mid point position and posture vector s _t=[x ₁(t) y ₁(t) θ ₁(t)] ^trepresent front vehicle body in the position of t and course angle, then the propons position and posture vector S in t+1 moment _t+1=[x ₁(t+1) y ₁(t+1) θ ₁(t+1), ^tbe expressed as with nonlinear discrete model

$S_{t+1}=S_t+T_s\left[\begin{array}{c}\begin{array}{cc}\cos {\mathrm{\&theta;}}_1\left(t\right)& 0\end{array}\\ \begin{array}{cc}\sin {\mathrm{\&theta;}}_1\left(t\right)& 0\end{array}\\ \begin{array}{cc}\frac{-\sin \mathrm{\&gamma;}\left(t\right)}{l_1\cos \mathrm{\&gamma;}\left(t\right)+l_2}& \frac{-l_2}{l_1\cos \mathrm{\&gamma;}\left(t\right)+l_2}\end{array}\end{array}\right]\left[\begin{array}{c}{v}_f\left(t\right)\\ {\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}}_1\left(t\right)\end{array}\right]$

The speed of current emulation moment front vehicle body is vf (t), and splice angle slewing rate is the time interval emulating this emulation last time is Ts, show that the angular velocity of front vehicle body is $\begin{array}{cc}& {\mathrm{\&omega;}}_{1}t=\frac{-\sin \mathrm{\&gamma;t}{v}_{f}t-l_2\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}t}{l_1\cos \mathrm{\&gamma;}\left(t\right)+l_2},\end{array}$

In formula ---splice angle slewing rate

$\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}t=\frac{\mathrm{\&gamma;t}-\mathrm{\&gamma;t}-1}{T_s},$

The course angle of front vehicle body equals a moment course angle and adds this increment emulated

θ ₁t＝θ ₁t-1+ω ₁(t)T _s，

The course angle of aftercarriage equals front vehicle body course angle and splice angle sum

θ ₂t＝θ ₁t+γT，

Show that vehicle propons mid point at the world coordinates of t is by front vehicle body travel speed and course angle:

$\left\{\begin{array}{c}{x}_{1}t=x_{1}t-1+[v_{f}t-1\cos {\mathrm{\&theta;}}_{1}t-1+v_{f}t\cos {\mathrm{\&theta;}}_{1}t]T_s/2\\ y_{1}t=y_{1}t-1+[v_{f}t-1\sin {\mathrm{\&theta;}}_{1}t-1+v_{f}t\sin {\mathrm{\&theta;}}_{1}t]T_s/2\end{array}\right.,$

According to geometric relationship, try to achieve point coordinate in t back axle

$\left\{\begin{array}{c}{x}_{2}t=x_{1}t-l_2\cos {\mathrm{\&theta;}}_2\left(t\right)+l_1\cos {\mathrm{\&theta;}}_1\left(t\right)\\ y_{2}t=y_{1}t-l_2\sin {\mathrm{\&theta;}}_2\left(t\right)+l_1\sin {\mathrm{\&theta;}}_1\left(t\right)\end{array}\right.$

The lifting of container is at the uniform velocity, is tried to achieve the value of ω 3 by the controling parameters of container, thus obtains lifting angle θ 3, when control inputs amount C value is 0, container declines, the packing case lifting when C value is 1, the lifting angle scope of container is 0 to 60 degree, and the lifting of container or sinking speed are:

$\begin{array}{cc}& \end{array}{\mathrm{\&omega;}}_{3}t=\left\{\begin{array}{cc}\frac{60T_s}{T_u}& (C=1)\\ \frac{60T_s}{T_d}& (C=0)\end{array}\right.,$

At the lifting angle of t container be:

${\mathrm{\&theta;}}_3\left(t\right)=\left\{\begin{array}{ccc}{\mathrm{\&theta;}}_3& t-1+{\mathrm{\&omega;}}_3\left(t\right)T_s& (C=1)\\ {\mathrm{\&theta;}}_3& t-1-{\mathrm{\&omega;}}_3\left(t\right)T_s& (C=0)\end{array}\right..$

2. system according to claim 1, is characterized in that, visual data model comprises the three-dimensional model of articulator, the three-dimensional model of underground passage and traffic mark.

3. system according to claim 1, is characterized in that, described vision simulation engine utilizes computer graphic image technology to generate the underground virtual environment that in vehicle operation, driver sees.

4. system according to claim 1, is characterized in that, described sound simulation engine can manufacture the sound of different-effect.