CN104881030B - Unmanned vehicle side Longitudinal data tracking and controlling method based on fast terminal sliding formwork principle - Google Patents

Abstract

The invention provides a kind of unmanned vehicle side Longitudinal data tracking and controlling method based on fast terminal sliding formwork principle, including：1) input and output parameter of selection unmanned vehicle side Longitudinal data tracking control unit；2) tracing control error and its state equation are defined；3) fast terminal sliding formwork is set up as state variable with tracing control error；4) fast terminal tendency rate is used as the sliding formwork tendency rate of tracing control；5) coupled relation between desired driving force or brake force and desired side force is derived from according to vehicle dynamic model and the above；6) expectation front wheel angle is calculated；7) according to the positive and negative of the inverse longitudinal force model output tried to achieve, judgement should currently calculate desired throttle opening or desired braking moment；8) desired throttle opening or braking moment are calculated.Be can see from simulation result, the present invention not only improves the error precision of Position Tracking Control, it may have the error precision of good speed tracking control.

Description

Unmanned vehicle side Longitudinal data tracking and controlling method based on fast terminal sliding formwork principle

【Technical field】

The present invention relates to pilotless automobile autonomous driving and sliding formwork control technical field, more particularly to one kind realizes nobody The tracking and controlling method of car side Longitudinal data.

【Background technology】

The motion control of automatic driving vehicle is the key technology of manipulation key-course in Navigation Control architecture, motion control Algorithm processed is the core research contents of this layer.Here motion control is the tracing control based on planned trajectory.Autonomous driving car Tracing control include longitudinal tracing control and lateral tracing control.Longitudinal tracing control is to control the travel speed of vehicle same Planning speed is consistent, and keeps certain operating range with front truck, and lateral tracing control is then the travel direction for controlling vehicle It is travelled along path planning, and meet basic performance requirement, including tracking accuracy, to vehicle parameter and environmental change Adaptability is robustness, and riding comfort etc..

When automatic driving vehicle performs the small curvature planning such as track holding to be acted, the lateral movement and lengthwise movement of vehicle Coupling can often ignore, carry out side longitudinal direction uneoupled control, separately design longitudinal tracking control unit and lateral tracing control Device.The research of longitudinal tracking control algorithm is devoted to solving being indulged with big under the influence of longitudinal direction of car dynamic system strong nonlinearity To the problem that longitudinally controlled precision is improved under the influence of disturbed condition.The method for being used has PID control, optimum control, self adaptation The Based Intelligent Controls such as control, sliding formwork control, fuzzy control and artificial neural-network control.Automatic cruising based on above-mentioned algorithm development System has been applied in some quality merchandise vehicles.Because lateral tracing control is to solve tracking problem based on two-dimensional space, Along with the change of vehicle and road parameters, and lateral movement unintentional nonlinearity characteristic so that the design of controller is often It is a problem for complexity, the control algolithm with self-correcting real-time learning ability is the emphasis of research.On the other hand, vehicle is worked as When the planning maneuvers of some complexity such as lane-change, intersection turning are carried out in the environment for exist moving obstacle, it is desirable to same When tracking planned position sequence and planning velocity series, due to vehicle lateral movement and lengthwise movement now have stronger coupling Conjunction property, if still using side longitudinal direction Uncoupling Control Based, it will produce larger tracking error.

Coupling effect of some researchers based on vehicle side lengthwise movement has carried out the research of side Longitudinal data control strategy, But the coupling control strategy of current side lengthwise movement is mainly for vehicle platoon control, motor-driven for single autonomous land vehicle Property the higher row control that is, such as vehicle carries out lane-change, intersection in the environment for exist moving obstacle and turns etc. that some are answered Miscellaneous planning maneuver, the less or control accuracy of research is relatively low.

The pertinent literature of retrieval given below：

[1] Wu Qing, He Zhiwei, the first elegant people, ancestor into column of traffic traveling control key technology in strong intelligent vehicle highway systems with Progress [J] traffic and computer, 2008,26 (4):154-157.

[2]Rajamani R.Vehicle Dynamics and Control.New York:Springer,2006.

[3]Zhou QZ,Wang FY and Li L.Robust Sliding Mode Control of 4WS Vehicles for Automatic Path Tracking[C].Proceedings of IEEE Intelligent Vehicles Symposium,Piscataway,USA,2005:819-826.

[4] Yongping, Hu Yujin, Li Chenggang, research [J] vapour of lateral deviation relaxed length characteristic under the big side drift angles of Guo Konghui are waited Turner journey, 2001 (2):78-81.

[5]Edward H,Lim M and Hedrick JK.Lateral and Longitudinal Vehicle Control Coupling for Automated Vehicle Operation[C].Proceedings of the American Control Conference San Diego,California,Jun.1999:3676-3680.

[6]Rajamani R,Tan HS,Law BK,et al.Demonstration of Integrated Longitudinal and Lateral Control for the Operation of Automated Vehicles in Platoons[J].IEEE Transactions on Control Systems Technology,2000,8(4):695- 708.

The such as [7] Li Yinong, willow, Zheng Ling are based on vehicle longitudinal and lateral coupling control [J] China mechanics of sliding formwork control Journey, 2007,18 (7):866-870.

[8]Yu X,Man Z,Wu Y.Terminal Sliding Modes with Fast Transient Performance[C].Proceedings of the 36th IEEE International Conference on Control&Decision,San Diego,1997:962-963.

[9] in double and, low buffeting fast robust sliding-mode control research [D] Harbin Institute of Technology thesis for the doctorate, 2000.

【The content of the invention】

It is an object of the invention to provide a kind of unmanned vehicle side Longitudinal data tracking control based on fast terminal sliding formwork principle Method processed, to solve above-mentioned existing theoretical and defect or deficiency present on design；The control method is for lifting controller Tracking performance, coupling is directly compensated by the controller design stage, unmanned vehicle is done more physical exercises obstacle in execution Lane-change in substance environment, intersection turn etc. some complicated, mobility planning behavior higher when, be capable of the high-precision of robust Tracking planning behavior, including tracking planned position state and speed state.

In order to realize above-mentioned purpose, the present invention is adopted the following technical scheme that：

Unmanned vehicle side Longitudinal data tracking and controlling method based on fast terminal sliding formwork principle, comprises the following steps：

Step one：The input and output parameter of selection unmanned vehicle side Longitudinal data tracking control unit；

Step 2：Define tracing control error and its state equation：

ε₁=X-X_d+Y-Y_d

Wherein (X, Y,) position coordinates that is respectively on controlled vehicle two dimensional surface and velocity yaw angle, (X_d,Y_d,) be respectively in trajectory planning algorithm institute planned trajectory and plan the position coordinates and velocity yaw angle of vehicle at point；

Step 3：Use tracing control error ε₁、ε₂As state variable, set up first order nonlinear switching function and design soon Fast terminal sliding mode face S₁And S₂：

Wherein p_α1＞ 0, p_β1＞ 0, p_α2＞ 0 and p_β2＞ 0 is sliding-mode surface single order and index term coefficient, and value is during emulation p_α1=p_α2=p_β1=p_β2=2；p_q1, p_p1, p_q2, p_p2Odd number is, is power exponent parameter, and meet p_q1＜ p_p1＜ 2p_q1, p_q2＜ p_p2＜ 2p_q2, value is p during emulation_q1=p_q2=5, p_p1=p_p2=7；

Step 4：Using fast terminal tendency rate formula as tracking control unit sliding formwork tendency rate：

Wherein f_α1＞ 0, f_β1＞ 0, f_α2＞ 0 and f_β2＞ 0 is fast terminal tendency rate single order and index term coefficient, emulation When value be f_α1=f_α2=80, f_β1=f_β2=2；f_q1, f_p1, f_q2, f_p2Odd number is, is power exponent parameter, and meet f_q1＜ f_p1 ＜ 2f_q1, f_q2＜ f_p2＜ 2f_q2, value is f during emulation_q1=f_q2=5, f_p1=f_p2=7；

Step 5：According to vehicle dynamic model and above-mentioned steps 1 to step 4 content be derived from desired driving force or Brake force F_trbrdWith desired side force F_ldBetween coupled relation：

Step 6：Calculate to obtain and expect front wheel angle：

Wherein C_fIt is the cornering stiffness of front tyre, l_fDistance of the front axle of vehicle to barycenter；υ is the linear velocity of vehicle；β is The side slip angle of vehicle；R is the angular speed of vehicle, and ψ is the course angle of vehicle,

Step 7：Ask for expecting driving force or desired braking power F for longitudinal direction of car power model_trbrdInverse for input is indulged To power model；If F_trbrdResult of calculation for just, then be desired driving force F_trd, then calculate desired throttle opening α_thb；, whereas if F_trbrdResult of calculation be negative, then be desired brake force F_brd, then calculate desired braking moment P_brd；

Step 8：Desired throttle opening α_thbComputational methods be：The elastic deformation of tire and power train is not considered, According to longitudinal direction of car power model, desired engine torque T_edWith current engine speed ω_e, can using inverse engine mockup In the hope of desired throttle opening α_thb：

α_thb=f_ieng(T_ed,ω_e)

Wherein f_ieng(T_ed,ω_e) represent inverse engine torque characteristics function；

Or, desired braking moment P_brdComputing formula be：P_brd=F_brd/K_br, K_brIt is desired brake force and system The proportionality coefficient of linear relationship between kinetic moment.

Unmanned vehicle centroid position changing coordinates are chosen in step one with a planning point position coordinates error X-X in planned trajectory_d、 Y-Y_dAnd unmanned vehicle velocity yaw angle is with planning point driftage angle errorIt is the |input paramete of tracking control unit；Section Valve opening α_thOr braking moment F_br, front wheel angle δ_fIt is tracking control unit output parameter.

The cornering stiffness C of front tyre_fNumerical value take the twice of single tire cornering stiffness.

Compared with prior art, advantage of the invention is as follows：When automatic driving vehicle autonomous driving completion mobility is stronger Driving behavior when, if current vehicle condition frequently occurs larger tracking error with expectation state, based on the inventive method reality Existing controller can promptly cut down tracking error, unmanned vehicle is quickly tracked expectation state, and in whole control process In not only there is stronger robustness to the uncertain factor of system, and satisfied dynamic quality can be obtained, same to time control System is simple, it is easy to accomplish.The present invention not only improves the error precision of Position Tracking Control, it may have good speed tracing control The error precision of system.

Step 5 of the present invention is to deriving in step 7 using vehicle side Longitudinal data kinetic model, in vehicle mobility There is more preferable model accuracy in stronger behavior.

Tracing control error ε is used in step 3 of the present invention₁、ε₂As state variable, built using first order nonlinear switching function Vertical fast terminal sliding formwork S₁、S₂, vehicle tracking control system tracking error is quickly converged to after sliding formwork surface state is reached The same desired locations of the current centroid position of zero, i.e. unmanned vehicle, current velocity vector course angle overlap with expectation course angle.

Fast terminal sliding formwork S is based in step 4 of the present invention₁、S₂Fast terminal tendency rate is set up as tracking control unit Sliding formwork tendency rate, can make the tracking error of vehicle tracking control system when sliding-mode surface is not at, in finite time compared with Weak shake or non-jitter from any state quickly reach sliding-mode surface, and more conventional method has stronger robustness.

【Brief description of the drawings】

Fig. 1 is unmanned vehicle tracking control system schematic diagram；

Fig. 2 is the unmanned vehicle side Longitudinal data tracking and controlling method flow chart based on fast terminal sliding formwork principle；

Fig. 3 is inverse engine torque characteristics function schematic diagram；

Fig. 4 is the pursuit path under target trajectory, coupling control and the pursuit path schematic diagram under uneoupled control；

Fig. 5 is comparing figure of the tracking error under coupling control with the tracking error under uneoupled control；Wherein, Fig. 5 (a) is The comparing figure of X-direction position tracking error, Fig. 5 (b) is the comparing figure of Y-direction position tracking error, and Fig. 5 (c) is X-direction speed The comparing figure of tracking error, Fig. 5 (d) is the comparing figure of Y-direction speed tracing error, and Fig. 5 (e) is that yaw angle (direction) tracks mistake Poor comparing figure；

Fig. 6 is the controlled quentity controlled variable schematic diagram of side Longitudinal data control algolithm；Fig. 6 (a) is the accelerator open degree of longitudinal tracing control Schematic diagram, unit is %, and Fig. 6 (b) is the brake-pedal load schematic diagram of longitudinal tracing control, and unit is N, and Fig. 6 (c) is lateral The front wheel angle schematic diagram of tracing control, unit is rad, and the controlled quentity controlled variable shown in figure meets the physical characteristic constraint of actuator.

【Specific embodiment】

The design is described in further detail according to the principle that side Longitudinal data is controlled.

Referring to Fig. 1, the design of tracking control unit when the present invention tracks planned trajectory for unmanned vehicle.

Referring to Fig. 2, unmanned vehicle side Longitudinal data tracking and controlling method of the present invention based on fast terminal sliding formwork principle is divided into Nine steps below, each step is specific as follows：

1) input and output parameter of unmanned vehicle side Longitudinal data tracking control unit is selected according to planned trajectory：

(1a) |input paramete：Unmanned vehicle centroid position changing coordinates are with a planning point position coordinates error X- in planned trajectory X_d、Y-Y_d；Unmanned vehicle velocity yaw angle is with planning point driftage angle errorWherein (X, Y,) it is respectively controlled car Position coordinates and velocity yaw angle on two dimensional surface, (X_d,Y_d,) it is respectively trajectory planning algorithm institute planned trajectory The position coordinates and velocity yaw angle of vehicle at upper planning point.

(1b) output parameter：Throttle opening α_th(or braking moment F_br)；Front wheel angle δ_f。

2) it is tracing control error according to fast terminal sliding formwork principle definition status variable, and provides its state equation：

(2a) state variable：

ε₁=X-X_d+Y-Y_d

The state equation of (2b) state variable：

The kinematical equation of vehicle is：

Wherein υ is the linear velocity of vehicle, and r is the angular speed of vehicle, and ψ is the course angle of vehicle, and β is the barycenter lateral deviation of vehicle Angle and

Kinematical equation according to vehicle can derive that the state equation of state variable is：

The further derivation of state equation to state variable：

3) fast terminal sliding-mode surface is designed based on vehicle kinematics equation：

(3a) uses tracing control error ε₁、ε₂As state variable, set up first order nonlinear switching function and design quick whole Hold sliding-mode surface S₁And S₂：

Wherein p_α1＞ 0, p_β1＞ 0, p_α2＞ 0 and p_β2＞ 0 is sliding-mode surface single order and index term coefficient, and value is during emulation p_α1=p_α2=p_β1=p_β2=2；p_q1, p_p1, p_q2, p_p2Odd number is, is power exponent parameter, and meet p_q1＜ p_p1＜ 2p_q1, p_q2＜ p_p2＜ 2p_q2, value is p during emulation_q1=p_q2=5, p_p1=p_p2=7.

(3b) is to fast terminal sliding-mode surface S₁And S₂Derivation is simultaneously brought vehicle kinematics equation into and is had：

4) fast terminal tendency rate formula is used as the sliding formwork tendency rate of tracking control unit：

Wherein f_α1＞ 0, f_β1＞ 0, f_α2＞ 0 and f_β2＞ 0 is fast terminal tendency rate single order and index term coefficient, emulation When value be f_α1=f_α2=80, f_β1=f_β2=2；f_q1, f_p1, f_q2, f_p2Odd number is, is power exponent parameter, and meet f_q1＜ f_p1 ＜ 2f_q1, f_q2＜ f_p2＜ 2f_q2, value is f during emulation_q1=f_q2=5, f_p1=f_p2=7.

5) tracking control unit is obtained according to fast terminal sliding-mode surface, sliding formwork Reaching Law and dynamics of vehicle coupled wave equation to expect The coupled relation of controlled quentity controlled variable.

(5a) dynamics of vehicle coupled wave equation：

Wherein F_lAnd R_lIt is respectively side force that front and rear tire is acted on chassis.F_fAnd F_rIt is respectively to act on antero posterior axis On longitudinal force, produced by power assembly and brakes.F_adFor before vehicle to air drag.δ_fIt is front wheel angle, l_fAnd l_rIt is Distance of the front axle and rear axle of vehicle to barycenter.L is the distance between vehicle antero posterior axis l_f+l_r。 μ is the conventional road surface coefficient of viscosity, μ=1 in the case of usual dry pavement, and has μ=0.5 under the surface conditions of water, and m is vehicle Quality, I_ψIt is the rotary inertia of vehicle.

Derivation, 4 of (5b) according to fast terminal sliding-mode surface in (3b)) in dynamics of vehicle coupling in sliding formwork tendency rate and (5a) Equation is closed, tracking control unit desired control amount F can be derived_trbrdAnd F_ldCoupled relation：

Wherein F_trbrdIt is desired driving force or brake force, F_ldIt is desired side force,F_rrFor Trailing wheel frictional ground force,q₃=cos (ψ+β)+ Sin (ψ+β), q₄=cos (ψ+β)-sin (ψ+β).

6) according to the relation between linear tire model and front-wheel synthesis side drift angle and front wheel angle, calculating is expected Front wheel angle：

(6a) linear tire model:

F_l=C_fδ₁

Wherein C_fIt is the cornering stiffness of front tyre, its numerical value takes the twice of single tire cornering stiffness, δ here₁It is front-wheel synthesis Side drift angle.

Relation between (6b) front-wheel synthesis side drift angle and front wheel angle：

(6c) is according to desired side force F in (5b)_ldObtain course changing control amount and expect front wheel angle：

7) to seek longitudinally controlled amount throttle opening α_thOr braking moment P_br, it is necessary to be directed to longitudinal direction of car power model ask for To expect driving force or desired braking power F_tbrdIt is the inverse longitudinal force model of input.If F_trbrdResult of calculation for just, then for Desired driving force F_trd, then desired throttle opening α need to be calculated_thb., whereas if F_trbrdResult of calculation be it is negative, then It is desired brake force F_brd, then need to calculate desired braking moment P_brd。

8) F is assumed_trbrdIt is desired driving force F_trd, calculate desired throttle opening α_thb。

(8a) according to it is foregoing set up longitudinal direction of car power model it is assumed that not considering the elastic deformation of tire and power train, root According to model, desired driving force is represented by：

F_trd=η_DT_edτ_T(ω_t/ω_e)f_gear(α_th,υ)i₀/h_t

Wherein η_DIt is vehicle transmission system power conveying system number, T_edIt is desired engine output torque, τ_TRepresent torque ratio Coefficient, its independent variable is ω_t/ω_e, it is fluid coupling secondary speed ω_tWith current engine speed ω_eRatio, f_gear (α_th, υ) and it is automatic transmission transmission ratio function, it is throttle opening α_th(fully closed is 0, and standard-sized sheet is 100%) non-with speed υ Linear function；i₀It is the gearratio of main reducing gear；h_tIt is the effective radius of wheel.

(8b) is by desired engine torque T_edWith current engine speed ω_e, can be in the hope of using inverse engine mockup Obtain desired throttle opening α_thb, it is expressed as follows against engine mockup：

α_thb=f_ieng(T_ed,ω_e)

Wherein f_ieng(T_ed,ω_e) represent inverse engine torque characteristics function.Using engine torque characteristics function f_eng (ω_e,α_th) and data are provided, can be in the hope of seeking the inverse engine of throttle opening by engine output torque and engine speed Torque characteristics function f_ieng(T_ed,ω_e), reference picture 3.

Or, it is assumed that F_trbrdIt is desired braking moment P_brd.Relational expression according to brake force and braking moment can be in the hope of It is against braking system model：

P_brd=F_brd/K_br

Wherein, K_brIt is the proportionality coefficient of linear relationship between desired brake force and braking moment.

A kind of unmanned vehicle side Longitudinal data tracking and controlling method based on fast terminal sliding formwork principle is given in the present invention, And simulating, verifying has been carried out to the control method using MATLAB.Be can see from the simulation result of Fig. 4-Fig. 6, when nobody drives When sailing vehicle autonomous driving and completing the stronger driving behavior of mobility, if current vehicle condition with expectation state frequently occur compared with Big tracking error, the controller realized based on the inventive method can promptly be cut down tracking error, unmanned vehicle is quickly tracked Expectation state.The present invention not only improves the error precision of Position Tracking Control, it may have the mistake of good speed tracking control Difference precision, and controlled quentity controlled variable is smooth and meets the constraint of the physical characteristic of actuator.

Claims (3)

1. the unmanned vehicle side Longitudinal data tracking and controlling method of fast terminal sliding formwork principle is based on, it is characterised in that including following Step：

Step one：The input and output parameter of selection unmanned vehicle side Longitudinal data tracking control unit；

Step 2：Define tracing control error and its state equation：

ε₁=X-X_d+Y-Y_d

${\stackrel{\·}{\mathrm{\ϵ}}}_1=\stackrel{\·}{X}-{\stackrel{\·}{X}}_d+\stackrel{\·}{Y}-{\stackrel{\·}{Y}}_d$

WhereinPosition coordinates and velocity yaw angle on vehicle two dimensional surface are respectively controlled,Point It is not the position coordinates and velocity yaw angle of vehicle at planning point in trajectory planning algorithm institute planned trajectory；

Step 3：Use tracing control error ε₁、ε₂As state variable, set up first order nonlinear switching function and design quick whole Hold sliding-mode surface S₁And S₂：

$S_1={\stackrel{\·}{\mathrm{\ϵ}}}_1+p_{\mathrm{\α}1}{\mathrm{\ϵ}}_1+p_{\mathrm{\β}1}{{\mathrm{\ϵ}}_1}^{p_{q1}/p_{p1}}$

$S_2={\stackrel{\·}{\mathrm{\ϵ}}}_2+p_{\mathrm{\α}2}{\mathrm{\ϵ}}_2+p_{\mathrm{\β}2}{{\mathrm{\ϵ}}_2}^{p_{q2}/p_{p2}}$

Wherein p_α1>0, p_β1>0, p_α2>0 and p_β2>0 is sliding-mode surface single order and index term coefficient, and value is p during emulation_α1=p_α2= p_β1=p_β2=2；p_q1, p_p1, p_q2, p_p2Odd number is, is power exponent parameter, and meet p_q1<p_p1<2p_q1, p_q2<p_p2<2p_q2, emulation When value be p_q1=p_q2=5, p_p1=p_p2=7；

Step 4：Using fast terminal tendency rate formula as tracking control unit sliding formwork tendency rate：

${\stackrel{\&CenterDot;}{S}}_1=-f_{\mathrm{\&alpha;}1}{\mathrm{\&beta;}}_1-f_{\mathrm{\&beta;}1}{S_1}^{f_{q1}/f_{p1}}$

${\stackrel{\&CenterDot;}{S}}_2=-f_{\mathrm{\&alpha;}2}{S}_2-f_{\mathrm{\&beta;}2}{S_2}^{f_{q2}/f_{p2}}$

Wherein f_α1>0, f_β1>0, f_α2>0 and f_β2>0 is fast terminal tendency rate single order and index term coefficient, and value is during emulation f_α1=f_α2=80, f_β1=f_β2=2；f_q1, f_p1, f_q2, f_p2Odd number is, is power exponent parameter, and meet f_q1<f_p1<2f_q1, f_q2< f_p2<2f_q2, value is f during emulation_q1=f_q2=5, f_p1=f_p2=7；

Step 5：Desired driving force or braking are derived to step 4 content according to vehicle dynamic model and above-mentioned steps 1 Power F_trbrdWith desired side force F_ldBetween coupled relation：

$\begin{array}{c}{F}_{trbrd}=-(q_3{f}_1+q_4{f}_2-\left({\stackrel{\&CenterDot;\&CenterDot;}{X}}_d+{\stackrel{\&CenterDot;\&CenterDot;}{Y}}_d\right)+p_{\mathrm{\&alpha;}1}{\stackrel{\&CenterDot;}{\mathrm{\&epsiv;}}}_1+\left(p_{\mathrm{\&beta;}1}{p}_{q1}/p_{p1}\right){{\mathrm{\&epsiv;}}_1}^{(p_{q1}-p_{p1})/p_{p1}}{\stackrel{\&CenterDot;}{\mathrm{\&epsiv;}}}_1\\ +f_{\mathrm{\&alpha;}1}{S}_1+f_{\mathrm{\&beta;}1}{S_1}^{f_{q1}/f_{p1}})/q_1{q}_3+F_{ld}(q_3{\mathrm{\&delta;}}_f-q_4)/q_3\end{array}$

Wherein,F_rrIt is trailing wheel frictional ground force, q₃=cos (ψ+β)+sin (ψ+β), q₄=cos (ψ+β)-sin (ψ+β), δ_fIt is front wheel angle, R_l It is side force that rear tyre is acted on chassis；F_fIt is to act on the longitudinal force on front axle, is produced by power assembly and brakes It is raw；l_fAnd l_rIt is the front axle and rear axle of vehicle to the distance of barycenter；L is the distance between vehicle antero posterior axis l_f+l_r； μ is the conventional road surface coefficient of viscosity, and m is the quality of vehicle, I_ψIt is the rotary inertia of vehicle；

Step 6：Calculate to obtain and expect front wheel angle：

${\mathrm{\&delta;}}_{fd}=F_{ld}/C_f+(\mathrm{\&beta;}+l_f\frac{r}{\mathrm{\&upsi;}})$

Wherein C_fIt is the cornering stiffness of front tyre, l_fDistance of the front axle of vehicle to barycenter；υ is the linear velocity of vehicle；β is vehicle Side slip angle；R is the angular speed of vehicle, and ψ is the course angle of vehicle,

Step 7：Ask for expecting driving force or desired braking power F for longitudinal direction of car power model_trbrdIt is the inverse longitudinal force of input Model；If F_trbrdResult of calculation for just, then be desired driving force F_trd, then calculate desired throttle opening α_thb； , whereas if F_trbrdResult of calculation be negative, then be desired brake force F_brd, then calculate desired braking moment P_brd；

Step 8：Desired throttle opening α_thbComputational methods be：The elastic deformation of tire and power train is not considered, according to Longitudinal direction of car power model, desired engine torque T_edWith current engine speed ω_e, can be in the hope of using inverse engine mockup Obtain desired throttle opening α_thb：

α_thb=f_ieng(T_ed,ω_e)

Wherein f_ieng(T_ed,ω_e) represent inverse engine torque characteristics function；

Or, desired braking moment P_brdComputing formula be：P_brd=F_brd/K_br, K_brIt is desired brake force and braking moment Between linear relationship proportionality coefficient.

2. the unmanned vehicle side Longitudinal data tracking and controlling method based on fast terminal sliding formwork principle according to claim 1, It is characterized in that：Unmanned vehicle centroid position changing coordinates are chosen in step one with a planning point position coordinates error X- in planned trajectory X_d、Y-Y_dAnd unmanned vehicle velocity yaw angle is with planning point driftage angle errorIt is the |input paramete of tracking control unit； Throttle opening α_thOr braking moment F_br, front wheel angle δ_fIt is tracking control unit output parameter.

3. the unmanned vehicle side Longitudinal data tracking and controlling method based on fast terminal sliding formwork principle according to claim 1, It is characterized in that：The cornering stiffness C of front tyre_fNumerical value take the twice of single tire cornering stiffness.