CN105405284A - Intelligent micro vehicle-road cooperative system - Google Patents

Abstract

The invention provides a miniature intelligent vehicle-road cooperation system, which is used for the technical field of intelligent traffic. The system comprises an intelligent miniature vehicle and a miniature road sand table. Solving the size and steering performance parameters of the intelligent miniature vehicle based on a scaling rule, and deducing an intelligent miniature vehicle speed control method by introducing a power factor; calculating the size of the sand table and the turning radius of the road according to a geometric similarity principle, and obtaining the friction coefficient of the sand table road by using the relation between the vehicle speed and the braking distance; by the intelligent miniature vehicle parameter scaling calculation method and the miniature road sand table parameter scaling calculation method, a miniature intelligent vehicle-road cooperation system capable of keeping physical properties similar between a model and a real object can be designed, accurate and reliable real object verification is provided for intelligent vehicle-road cooperation technology research, and real simulation data are obtained. Reducing the high traffic test cost.

Description

A kind of intelligent micro bus or train route cooperative system

Technical field

The invention belongs to technical field of intelligent traffic, be specifically related to a kind of bus or train route cooperative system based on scale model.

Background technology

At the current bus or train route cooperative system research initial stage, actual scene improvement cost is too high, and system operating conditions is complicated and changeable, and large in traffic scene experiment difficulty, experiment also exists certain risk, is difficult to operation.Based on the contracting of similarity theory than the simulated experiment scene of bus or train route cooperative system, by the research and analysis completing test that traffic system testing crew can be helped correct, quick, economic to the test of scale model.Utilize model test to predict the traffic characteristics of large-scale master mould, significant to the research of novel intelligent traffic system.The test result consistance of scale model and master mould is better, and model can carry out repeated experiment, reduces experimentation cost, shortens research cycle and rational correlation test data, significant to the research of bus or train route cooperative system.

Because direct to be applied in actual traffic by novel bus or train route coordination technique is carried out test and be there is security risk in prior art, and testing expenses are high is even difficult to operation.Software Simulation Test can not meet various requirement of experiment, and data acquisition authenticity is poor, simulation value and the measured value goodness of fit poor.Existing traffic simulation software vehicle operating depends on car-following model and there is relatively large deviation between road transformation model and actual vehicle running status, and software emulation but just functional emulation, the emulation relating to wireless telecommunications, sequential and so on cannot simulated implementation accurately.It is poor that emulated data obtains authenticity, and simulation result accuracy is low.Current traffic experiment sand table testing field scenes function imperfection, mainly realize information acquisition and signal controls, not integrated novel bus or train route coordination technique, the model car intelligence degree run in sand table is lower, and they cannot meet bus or train route and work in coordination with the requirement not having emulation platform.And common traffic miniatures design is the model reduced according to fixing geometric proportion, very few to the physical property similarity consideration of model.This miniatures can not simulate traffic environment really.

Summary of the invention

According to above deficiency, the present invention proposes a kind of intelligent micro bus or train route cooperative system.The following technical scheme of concrete employing: system comprises intelligent micro car and micro road sand table, intelligent micro car comprises car body, rear axle and tire, front axle and tire, vehicle frame, direct current generator, accumulator, RFID card reader, core master control borad, steering engine, ultrasonic distance measuring module; Micro road sand table comprises ETC no-stop charging system, trackside controller, video detector, microwave detector, geomagnetism detecting device, coil checker, variable information board, traffic lights, RFID module;

Intelligence micro car vehicle velocity V m is arranged according to following formula:

$V_m=\sqrt{\frac{21.15}{C_m{A}_m}(\frac{T_{em}{i}_{im}{\mathrm{\η}}_m}{r_m}-\frac{\frac{T_e{i}_i\mathrm{\η}}{r_z}-\frac{{\mathrm{CAV}}^2}{21.15}}{rG\·G_m})}$

In formula: T _emthe torque of-intelligent micro car engine; r _m-intelligent micro car owner driving wheel radius; i _im-intelligent micro car vehicle drive system overall ratio; C _m-intelligent micro car coefficient of air resistance; A _m-intelligent micro car front face area; Gm-intelligence micro car quality; η _m-intelligent vehicle transmission efficiency; R-intelligence micro car is relative to the micro ratio of former car; The former car quality of G-; The former car engine torque of Te-; r _z-former car owner's driving wheel radius; i _ithe overall ratio of-former car vehicle drive system i-th grade; The former car coefficient of air resistance of C-; The former car front face area of A-; η-former car transmission efficiency;

The bend cross fall i of micro road _harrange according to following formula:

$\frac{V^2}{127R}-\mathrm{\&mu;}<i_h<\frac{B}{2h}$

In formula: B-axletree distance, h-vehicle's center of gravity height, V – intelligent vehicle speed, R-turning radius, the transverse force of μ-unit car weight;

Micro pavement of road coefficientoffrictionμ ' arrange according to following formula:

${\mathrm{\&mu;}}^{\&prime;}=\frac{V_{\mathrm{\&alpha;}}^2}{254\left(\frac{V\mathrm{\&alpha;}(t-0.72)}{10}+\frac{{\mathrm{V\&alpha;}}^2}{130}\right)}\&PlusMinus;i$

In formula: x-braking starts to stopping time distance; V _α-car brakeing initial velocity; I-road surface longitudinal gradient; T-intelligent micro damping force increases the time experienced.

The present invention has following technique effect: reduced according to a certain percentage according to the principle of similitude by material object, and physical property between model and material object can be kept to coincide, for intelligent bus or train route coordination technique research provides physical varification accurately and reliably.

Accompanying drawing explanation

Fig. 1 is intelligent micro bassinet structure schematic diagram

Fig. 2 is equipment installation site schematic diagram

Embodiment

The contracting of the present invention's intelligence comprises intelligent micro car and micro sand table than bus or train route cooperative system, and intelligent micro car is the intelligent vehicle based on scale model, and actual vehicle is scaled, and contracting than coefficient is for keeping intelligent micro car similar to former car physical property, corresponding parameter scale reduction method need be set up.

Intelligence micro bassinet structure and each function mounting position as shown in Figure 1:

1 direct current generator (intelligent carriage rear wheel driving axle place, installation site);

2 accumulators (control module lower end, installation site, near motor place);

3RFID card reader (intelligent carriage domain, installation site place);

4 core master control borads (intelligent vehicle geometric center place, installation site supports with a carbon element bar);

5 steering engines (in the middle part of the front axle of installation site, being connected with front axle two wheel by control lever);

6 ultrasonic distance measuring modules (intelligent carriage front end, installation site, is connected with master control borad);

7 rear axles and tire

8 front axles and tire

9 vehicle frames

One, intelligent micro car physical dimension:

The basic demand of scale model design is that model keeps similar to prototype, and according to geometric similarity principle, prototype plant size/scale model plant bulk is r.Each structural parameters of scale model are calculated as follows:

(1) the length L of life size automobile _owith the length L of intelligent micro car _mfixing.Intelligence micro car size is that following formula can draw by the size of micro car is calculated compared with the size of life size automobile:

$\frac{L_m}{L_0}=\frac{1}{r}$

(2) overall width namely extreme along intelligent vehicle Width both sides between distance size, computing method are as follows

$\frac{W_m}{W_0}=\frac{1}{r}$

(3) overall height is namely along intelligent vehicle peak to ground distance size, and computing method are as follows:

$\frac{H_m}{H_0}=\frac{1}{r}$

Two, intelligent micro vehicle speed control method

In order to evaluate the kinematic behavior of former car model and intelligent micro vehicle model, need the concept introducing dynamic factor.The outstanding parameter embodying automobile power characteristic is speed, therefore does following derivation to parameter:

(1) tractive force F _twith the difference of air resistance Fw and the ratio of vehicular gross combined weight G, be called dynamic factor, represent with D.

$D=\frac{F_t-F_w}{G}---\left(2\right)$

Wherein:

$F_t=\frac{T_e{i}_i\mathrm{\&eta;}}{r_z},F_w=\frac{{\mathrm{CAV}}^2}{21.15}---\left(3\right)$

In formula: Te-motor torque; r _z-driving wheel radius; i _ithe overall ratio that-vehicle drive system is i-th grade;

C-coefficient of air resistance; A-front face area; D-dynamic factor;

Above-mentioned formula (3) is substituted in (2), can derive and draw

$D=\frac{\frac{T_e{i}_i\mathrm{\&eta;}}{r_Z}-\frac{{\mathrm{CAV}}^2}{21.15}}{G}$

(2) based on contracting than rule, the kinematic behavior contracting of intelligent micro car is than the 1/r for former automobile power characteristic, and namely the dynamic factor of micro car is the 1/r of former automobile power factor, namely

$D_m=\frac{1}{r}D$

The parameter of derivation to intelligent micro car of the former automobile parameter of analogy can derive thus, and finally obtain intelligent micro vehicle speed and former car speed corresponding relation formula:

$V_m=\sqrt{\frac{21.15}{C_m{A}_m}(\frac{T_{em}{i}_{im}{\mathrm{\&eta;}}_m}{r_m}-\frac{\frac{T_e{i}_i\mathrm{\&eta;}}{r_z}-\frac{{\mathrm{CAV}}^2}{21.15}}{rG\&CenterDot;G_m})}$

In formula: T _emthe torque of-intelligent micro car engine; r _m-intelligent micro car owner driving wheel radius; i _im-intelligent micro car vehicle drive system overall ratio; C _m-intelligent micro car coefficient of air resistance; A _m-intelligent micro car front face area; Gm-intelligence micro car quality; η _m-intelligent vehicle transmission efficiency; R-intelligence micro car is relative to the micro ratio of former car; The former car quality of G-; The former car engine torque of Te-; r _z-former car owner's driving wheel radius; i _ithe overall ratio of-former car vehicle drive system i-th grade; The former car coefficient of air resistance of C-; The former car front face area of A-; η-former car transmission efficiency;

Intelligence micro car power is supplied by the direct current generator being arranged on rear axle power system.Direct current generator motor speed when not considering armature circuit reactance pressure drop is directly proportional to the terminal voltage be attached on motor.The voltage swing of intelligence micro car control circuit by regulating PWM Duty ratio control driving chip to supply direct current generator, to reach the object of control rate.

(3) intelligent micro vehicle speed and control circuit export PWM ripple pulsewidth computing method

If when motor switches on power all the time, motor both end voltage is U _max, the maximum V of rotating speed _maxif PWM ripple dutycycle is D.T is pulse signal cycle, t ₁for high level duration, then the average voltage of motor is:

U _d＝U _max·D

$U_d=U_{max}\&CenterDot;\frac{t_1}{T}$

In formula: U _d-electric moter voltage mean value; U _max-motor two ends maximum voltage; D=t ₁/ T-dutycycle.

From formula, when T remains unchanged, the voltage of motor is along with t ₁change and change, different voltage can be obtained, thus reach and change the object of motor speed.

Motor speed V _mwith voltage pulse width relational expression be:

$V_m=V_{max}\&CenterDot;\frac{t_1}{T}$

Three, intelligent micro car rotating direction control method

(1) by steering wheel torque balance equation can be obtained to steering system structural force analysis:

$m_{r}K{\stackrel{\&CenterDot;\&CenterDot;}{\mathrm{\&theta;}}}_L+C_{r}K{\stackrel{\&CenterDot;}{\mathrm{\&theta;}}}_L=F_{tr}-\frac{K_m{\mathrm{\&theta;}}_L}{R_1}-T_m$

In formula: m _rthe equivalent quality in steering linkage such as-wheel and steering gear; C _rthe equivalent damping coefficient of-steering linkage; K _mthe rigidity of-steering engine; θ _lthe corner of-steering wheel; The scale-up factor of the displacement of K-steering linkage and wheel steering angle; F _tr-steering drag; R ₁the length of-steering wheel rocking arm; T _m-steering wheel Driving Torque;

(2) steering of intelligent micro car can be reduced to motor armature voltage U for input, the linear mathematical model that wheel steering wheel rotational angle theta position exports.According to the principle of work of direct current generator, electromagnetic torque and the armature supply of steering wheel are proportional, that is:

T _m＝K _iI _e

In formula: K _ithe torque constant of-steering wheel; I _ethe armature supply of-steering wheel;

Therefore corner can be controlled by the electric current controlling steering wheel.For direct current generator, between electric current and voltage, there is following relation:

$U=L\frac{dI}{dt}+K_e{w}_m+RI$

In formula: K _ethe back electromotive force constant R-motor armature resistance L-motor armature inductance of-motor

I-motor current ω-motor angular velocity

Induction Solved by Laplace Transformation is carried out to above formula and obtains relation between current/voltage and steering wheel rotational angle theta:

U(s)＝L·s·I(s)+K _eω _m(s)+R·I(s)

Again

${\mathrm{\&omega;}}_m=\frac{\mathrm{\&theta;}}{T}$

Substitution can obtain:

$U\left(s\right)=L\&CenterDot;s\&CenterDot;I\left(s\right)+-K_e\frac{\mathrm{\&theta;}}{T}+R\&CenterDot;I\left(s\right)$

(3) steering wheel turns to pwm control signal to calculate

The steering wheel pulse-width control signal cycle is T, and rotational angle amplitude peak is θ, and control circuit processor resolution is K.Then servos control precision is:

$I=\frac{T}{K}$

The control accuracy of PWM is

$P=\frac{\mathrm{\&theta;}}{K}$

When steering wheel adjustment angle is ω, PWM rising time t dutycycle should be:

$t=\frac{\mathrm{\&omega;}}{P}\&CenterDot;I$

Namely

$t=\frac{\mathrm{\&omega;}K}{\mathrm{\&theta;}}\&CenterDot;\frac{T}{K}=\frac{\mathrm{\&omega;}T}{\mathrm{\&theta;}}$

(4) computing method of the corresponding intelligent micro car steering wheel pwm control signal rising edge t of rotation angle of automotive steering wheel

The former rotating of steering wheel number of turns and angular relationship:

Angular gear ratio:

Wherein: α-driver pinion pressure angle; β-pinion wheel anglec of rotation; i _w0-angular gear ratio; w _p-steering wheel angle speed; Wk-steering knuckle yaw rate;

For the ease of research, above-mentioned discussed angular gear ratio i can be thought _wbe the ratio of rotating of steering wheel angle and vehicle wheel rotation angle.

In sum: when actual rotation angle of automotive steering wheel is ω, corresponding intelligent micro car PWM rising time t length should be pass and is:

Micro road sand table structure and installation site show as shown in Figure 2:

1) ETC no-stop charging system (road section bayonet socket place, installation site);

2) trackside controller (outside the intersection of installation site);

3) video detector (after the stop line of installation site, supporting with a semi-girder vertical rod);

4) microwave detector (after the stop line of installation site, being fixed in vertical rod);

5) geomagnetism detecting device (after the stop line of installation site, being embedded in underground);

6) coil checker (after the stop line of installation site, being embedded in underground);

7) variable information board (on front side of the ETC no-stop charging system of installation site);

8) traffic lights (installation site intersection supports with a semi-girder vertical rod);

9) RFID module (on front side of the ETC no-stop charging system of installation site, being embedded in underground);

One, contract than sand table road dimensions

1) Size calculation is compared in road contracting

According to geometric similarity principle, prototype road dimensions/scale model road dimensions is r, according to the structural parameters of ratio of similitude determination scale model.Road parameters computing method are as follows:

A, contract than road dimensions be by contracting calculate compared with the size of original path than the size of road, link length is calculated as follows:

$\frac{L_m}{L_0}=\frac{1}{r}$

B, road computing method of having a lot of social connections are as follows:

$\frac{W_m}{W_0}=\frac{1}{r}$

Two, micro road curve scene

1) contracting is than road curve cross fall computing method

The lower limit of a, cross fall

Because intelligent micro car travels the effect being subject to centrifugal force on bend, and the stability influence that centrifugal force travels on horizontal curve intelligent micro car is very large, horizontal sliding may be produced or laterally topple, in order to reduce the effect of centrifugal force, ensure that intelligent micro car is stable on horizontal curve to travel, the road surface on horizontal curve must be made to make, and outside is high, the low form in unidirectional horizontal wall inscription in inner side, is called horizontal superelevation (superelevation), i.e. cross fall i.

After being provided with superelevation, the horizontal component Gsin α of car weight can offset a part of centrifugal force, its remaining part

Divide and balanced by the friction resistance between intelligent micro vehicle tyre and road surface.

As shown in the figure, centrifugal force F and car weight G is decomposed into the transverse force being parallel to road surface and perpendicular to road

The vertical force in face, that is:

Transverse force: X=Fcos α-Gsin α

Vertical force: Y=Fsin α+Gcos α

Because road surface horizontal wall inscription is little, namely α is very little, can think

Sin α ≈ tan α=i _h, cos α ≈ 1, i _hbe called the horizontal superelevation gradient;

Thus: $X=F-{\mathrm{Gi}}_h=\frac{{\mathrm{Gv}}^2}{gR}-{\mathrm{Gi}}_h=G\left(\frac{v^2}{gR}-i_h\right)$

Transverse force X is the labile factor that intelligent micro car travels, and vertical force is ballast.With regard to transverse force, be only the degree of stability that cannot reflect Different Weight intelligence micro car from the size of its value.If the transverse force effect of such as 5kN onboard, it may be made to produce the danger of laterally toppling, and it heavier intelligent vehicle may be then safe for acting on.So adopt cornering ratio to weigh extent of stability, its meaning is the transverse force of unit car weight, namely

$\mathrm{\&mu;}=\frac{X}{G}=\frac{v^2}{gR}-i_h$

Above-mentioned formula is expressed, then with V (km/h)

$\mathrm{\&mu;}=\frac{V^2}{127R}-i_h$

I.e. cross fall i _hlower limit is

$i_h>i=\frac{V^2}{127R}-\mathrm{\&mu;}$

The upper limit of b, cross fall

Vehicle travels or when taking a sudden turn, is the danger that the unlikely generation of intelligent micro car is overturned around left and right wheels on the road of transverse pitch, requires that in road curve design be satisfied certain requirement.

When vehicle occurs laterally to topple, vehicle is rotated with road surface contact point by right wheel, and revolver will leave road surface, i.e. P ₁=0, then

Ghsinα-GBcosα/2＝0

In formula: B-axletree is apart from h-vehicle's center of gravity height G-gross combination weight.

The cross fall angle occurred when laterally toppling is:

$tan\mathrm{\&alpha;}=\frac{B}{2h}$

Therefore when carrying out bend design, the value of slope i that the discrepancy in elevation inside and outside bend is formed _hmeet following formula:

$i_h<i=\frac{B}{2h}$

Therefore can be obtained by above-mentioned derivation, the computing formula of bend cross fall is as follows:

$\left\{\begin{array}{c}{i}_h>i=\frac{V^2}{127R}-\mathrm{\&mu;}\\ i_h<i=\frac{B}{2h}\end{array}\right.$

2) contracting is than road curve radium computing method

A, the horizontal condition analysis that topples

Laterally topple: intelligent micro car, under the effect of transverse force, may produce the danger of outwards toppling around outboard wheels touchdown point.

Stable condition: upsetting moment is less than or equal to stabilizing moment.That is:

Xh _g≤Y _b/2＝(F _ih+G)*b/2

In formula: h _g-Che height of C.G.; X-transverse force X=Fcos α-Gsin α;

Y-vertical force Y=Fsin α+Gcos α; Width between b-two wheelspan;

F _ih-centrifugal force vertical force component;

Because of i _husually smaller, therefore F _ihbe much smaller than G, thus

$\mathrm{\&mu;}=\frac{X}{G}\&le;b/2h_g$

R=V again ²/ 127 (μ+i _h), thus

Utilize above formula can obtain intelligent micro car on horizontal curve, do not produce the minimum radius of horizontal curve laterally toppled.B, horizontal sliding term restriction method

Horizontal sliding: intelligent micro car, under the effect of transverse force, may produce the lateral sliding of transversely force direction.

Stable condition: transverse force is less than or equal to the horizontal adhesion between tire and road surface, that is:

In formula: for lateral adhesion coefficient;

X-transverse force X=Fcos α-Gsin α;

Y-vertical force Y=Fsin α+Gcos α;

By ?

Therefore can be obtained by above-mentioned derivation, the computing formula of turning radius is as follows:

Three, micro sand table surface friction coefficient computing method

Relation according to road friction coefficient and car speed and braking distance:

${\mathrm{\&mu;}}^{\&prime;}=\frac{{V_a}^2}{254\left(x-\frac{V\mathrm{\&alpha;}\&CenterDot;t}{7.2}\right)}\&PlusMinus;i$

In formula: x-braking starts to stopping time distance; V _α-micro intelligent vehicle initial speed of braking; μ '-road surface profile frictional coefficient; I-road surface longitudinal gradient; T-intelligent micro damping force increases the time experienced;

Wherein

$x=0.1V_{\mathrm{\&alpha;}}+\frac{V_{\mathrm{\&alpha;}}^2}{130}$

Substitute into:

${\mathrm{\&mu;}}^{\&prime;}=\frac{V_{\mathrm{\&alpha;}}^2}{254\left(\frac{V\mathrm{\&alpha;}}{10}+\frac{{\mathrm{V\&alpha;}}^2}{130}-\frac{V_{\mathrm{\&alpha;}}\&CenterDot;L}{7.2}\right)}\&PlusMinus;i$

That is:

${\mathrm{\&mu;}}^{\&prime;}=\frac{V_{\mathrm{\&alpha;}}^2}{254\left(\frac{V\mathrm{\&alpha;}(t-0.72)}{10}+\frac{{\mathrm{V\&alpha;}}^2}{130}\right)}\&PlusMinus;i.$

Claims (1)

1. a system, particularly a kind of intelligent micro bus or train route cooperative system, it comprises intelligent micro car and micro road sand table, it is characterized in that: intelligent micro car comprises car body, rear axle and tire, front axle and tire, vehicle frame, direct current generator, accumulator, RFID card reader, core master control borad, steering engine, ultrasonic distance measuring module; Micro road sand table comprises ETC no-stop charging system, trackside controller, video detector, microwave detector, geomagnetism detecting device, coil checker, variable information board, traffic lights, RFID module;

Intelligence micro car vehicle velocity V m is arranged according to following formula:

$V_m=\sqrt{\frac{21.15}{C_m{A}_m}(\frac{T_{em}{i}_{im}{\mathrm{\&eta;}}_m}{r_m}-\frac{\frac{T_e{i}_i\mathrm{\&eta;}}{r_z}-\frac{{\mathrm{CAV}}^2}{21.15}}{rG\&CenterDot;G_m})}$

In formula: T _emthe torque of-intelligent micro car engine; r _m-intelligent micro car owner driving wheel radius; i _im-intelligent micro car vehicle drive system overall ratio; C _m-intelligent micro car coefficient of air resistance; A _m-intelligent micro car front face area; Gm-intelligence micro car quality; η _m-intelligent vehicle transmission efficiency; R-intelligence micro car is relative to the micro ratio of former car; The former car quality of G-; The former car engine torque of Te-; r _z-former car owner's driving wheel radius; i _ithe overall ratio of-former car vehicle drive system i-th grade; The former car coefficient of air resistance of C-; The former car front face area of A-; η-former car transmission efficiency;

The bend cross fall i of micro road _harrange according to following formula:

$\frac{V^2}{127R}-\mathrm{\&mu;}<i_h<\frac{B}{2h}$

In formula: B-axletree distance, h-vehicle's center of gravity height, V – intelligent vehicle speed, R-turning radius, the transverse force of μ-unit car weight;

Micro pavement of road coefficientoffrictionμ ' arrange according to following formula:

${\mathrm{\&mu;}}^{\&prime;}=\frac{V_{\mathrm{\&alpha;}}^2}{254(\frac{V\mathrm{\&alpha;}(t-0.72)}{10}+\frac{{\mathrm{V\&alpha;}}^2}{130})}\&PlusMinus;i$

In formula: x-braking starts to stopping time distance; V _α-micro intelligent vehicle initial speed of braking; I-road surface longitudinal gradient; T-intelligent micro damping force increases the time experienced.