CN106184225A - Longitudinal automobile speedestimate method that distributed type four-wheel-driven electrical vehicular power controls - Google Patents

Abstract

The invention discloses a kind of longitudinal automobile speedestimate method controlled for distributed type four-wheel-driven electrical vehicular power, it comprises the following steps: S10, the described rough estimation block of vehicle reference speed freely roll wheel speed according to motor speed and wheel speed estimation；Utilize yaw velocity and steering wheel angle signal freely to roll wheel speed by 4 and be converted to speed at vehicle centroid；Utilize speed calculation vehicle reference speed coarse value at vehicle centroid；S20, described vehicle body deceleration coarse value estimation block utilize Motor torque, brake pressure, motor speed or wheel speed, yaw velocity and steering wheel angle signal estimation vehicle body deceleration coarse value；Reference speed coarse value and vehicle body deceleration coarse value that S30, described Kalman filtering module utilize steady-state Kalman filter to be calculated step S10 and S20 are filtered, and estimate and export reference speed and automobile body deceleration.Longitudinal automobile speedestimate method for the control of distributed type four-wheel-driven electrical vehicular power of the present invention has higher real-time and precision.

Description

Longitudinal automobile speedestimate method that distributed type four-wheel-driven electrical vehicular power controls

Technical field

The present invention relates to the self adaptation longitudinal velocity observer that a kind of new distributed type four-wheel-driven electrical vehicular power controls, especially It relates to the longitudinal velocity evaluation method that a kind of distributed type four-wheel-driven electrical vehicular power controls.

Background technology

In distributed type four-wheel-driven electrical vehicular power control system, the accuracy of longitudinal speed directly affects whole with real-time The final effect of individual dynamics Controlling.There is presently no and a kind of can directly measure the simple of vehicular longitudinal velocity, economical, be suitable for and Reliable method again.Measuring automobile barycenter absolute velocity with GPS position finder, its real-time and accuracy all can not meet control Requirement.The motion relative to road surface of the automobile barycenter is measured again to weather by optical principle, condition of road surface, use environment the quickest Sense.Therefore, the method that measurement and mathematical model combine indirectly can only be used to estimate automobile longitudinal speed.In recent years, many Scholar proposes the evaluation method of many vehicular longitudinal velocities for distributed-power control system, from the literary composition published From the point of view of offering, it is primarily present problems with: evaluation method excessively idealizes, it is difficult to actual application；Have employed the evaluation method of complexity, It is appropriate only for emulation, it is difficult to run on single-chip microcomputer, be unsatisfactory for requirement of real-time；Real-time reaches requirement, but estimation precision is again Not enough.

It is therefore desirable to searching one can either avoid disadvantage mentioned above can estimate again longitudinal direction of car speed the most accurately and real-time The method of degree.

Summary of the invention

It is an object of the present invention to provide a kind of longitudinal automobile speedestimate method controlled for distributed type four-wheel-driven electrical vehicular power, It, for defect present in above-mentioned prior art, is started with, based on be widely used at present in terms of real-time and accuracy two Automobile sensor and design.

The present invention solves technical problem and adopts the following technical scheme that a kind of for the control of distributed type four-wheel-driven electrical vehicular power Longitudinal automobile speedestimate method, it comprises the following steps:

S10, the described rough estimation block of vehicle reference speed freely roll wheel speed according to motor speed and wheel speed estimation；Profit Freely roll wheel speed with yaw velocity and steering wheel angle signal by 4 and be converted to speed at vehicle centroid；Utilize vehicle matter Speed calculation vehicle reference speed coarse value at the heart；

S20, described vehicle body deceleration coarse value estimation block utilize Motor torque, brake pressure, motor speed or wheel Speed, yaw velocity and steering wheel angle signal estimation vehicle body deceleration coarse value；

S30, described Kalman filtering module utilize the ginseng that step S10 and S20 are calculated by steady-state Kalman filter Examine speed coarse value and vehicle body deceleration coarse value is filtered, estimate and export reference speed and automobile body deceleration.

Optionally, use following formula to calculate and freely roll wheel speed v_free, i:

$v_{free,i}=\frac{v_{w,i}\·C_{\mathrm{\λ},i}}{C_{\mathrm{\λ},i}-{\mathrm{\μ}}_i}---\left(1\right)$

$C_{\mathrm{\λ},i}=\frac{{\mathrm{\μ}}_i}{{\mathrm{\λ}}_{w,i}}---\left(2\right)$

In formula, v_w,iFor wheel speed, C_λ,iFor tire stiffness, λ_w,iFor wheel slip, μ_iAttachment coefficient, i=1,2,3,4.

Optionally, speed v at vehicle centroid is calculated by following formula_x,i, i=1,2,3,4:

$v_{x,1}=\frac{v_{free,1}-\stackrel{\·}{\mathrm{\ψ}}\·l_a\·{\mathrm{sin\δ}}_f}{{\mathrm{cos\δ}}_f}-\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}-v_y\·{\mathrm{tan\δ}}_f---\left(3\right)$

$v_{x,2}=\frac{v_{free,2}-\stackrel{\·}{\mathrm{\ψ}}\·l_a\·{\mathrm{sin\δ}}_f}{{\mathrm{cos\δ}}_f}-\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}-v_y\·{\mathrm{tan\δ}}_f---\left(4\right)$

$v_{x,3}=v_{free,3}-\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}---\left(5\right)$

$v_{x,4}=v_{free,4}+\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}---\left(6\right)$

In formula,For yaw velocity, δ_fFor steering wheel angle, t_wFor wheelspan, l_aFor barycenter to front axle distance, v_yFor laterally Speed.

Optionally, speed calculation vehicle reference speed coarse value v at vehicle centroid is utilized_{x_raw}Realized by following formula:

$v_{x\_raw}=\underset{i=0}{\overset{3}{\Σ}}(k_i\·v_{x,i})/\underset{i=0}{\overset{3}{\Σ}}{k}_i$

In formula, k_iFor wheel stability sex factor.

Optionally, described vehicle body deceleration coarse valueFollowing formula can be used to calculate:

${\hat{a}}_{x\_raw}=\frac{1}{m}\[(F_{x,1}+F_{x,2}){\mathrm{cos\δ}}_f+{\mathrm{\Δsin\δ}}_f+F_{x,3}+F_{x,4}+F_{wind}\]---\left(8\right)$

$F_{x,i}=\frac{1}{r_{w,i}}\[\frac{J_{w,i}}{r_{w,i}}\{a_{w,i}+{\mathrm{\ζ}}_1(v_{w,i}-{\hat{v}}_{w,i})\}+T_{b,i}-T_{d,i}\]---\left(9\right)$

$\mathrm{\Δ}=\frac{-(F_{x,1}+F_{x,2})\·(l_a+l_b){\mathrm{sin\δ}}_f+(F_{x,1}-F_{x,2})\·{\mathrm{cos\δ}}_f\·l_b+(F_{x,3}-F_{x,4})\·\frac{t_w}{2}-J_z\·\stackrel{\·\·}{\mathrm{\ψ}}-m\·{\stackrel{\·}{v}}_y\·l_b-m\·v_x\·\stackrel{\·}{\mathrm{\ψ}}\·l_b}{(l_a+l_b)\·{\mathrm{cos\δ}}_f}---\left(10\right)$

In formula, m is complete vehicle quality；F_windFor windage；F_x,iFor wheel longitudinal force, i=1,2,3,4；r_w,iFor radius of wheel； T_b,iFor brake force；T_d,iFor driving force, J_zFor vehicle around the rotary inertia of z-axis, l_bFor barycenter to rear axle distance；J_w,iTurn for wheel Dynamic inertia, i=1,2,3,4；a_w,iFor the acceleration of wheel, i=1,2,3,4；ζ₁For the estimation factor, obtained by look-up table； For estimating wheel speed, i=1,2,3,4；For yaw angle acceleration；For lateral car acceleration；v_xSpeed for the direction of advance of vehicle Degree.

There is advantages that

1. the present invention is provided with longitudinal automobile speedestimate system, it include Motor torque, motor speed, wheel speed, brake pressure, Yaw velocity and steering wheel angle signal, the rough estimation block of vehicle reference speed, vehicle body deceleration coarse value estimation block and Kalman filtering module；Compared with prior art, longitudinal speed of the distributed electrical motor-car dynamics Controlling that the present invention is set up The good fast operation of evaluation method real-time, be not only applicable to distributed type four-wheel-driven electric motor car longitudinal direction speed real-time estimation and also slightly Longitudinal automobile speedestimate of other vehicles it is also applied for after making an amendment.

2. to be converted to the conversion regime of speed at vehicle centroid peculiar by the present invention for the wheel speed that freely rolls in the present invention, Actual application shows that this transformation energy significantly improves computational accuracy.

3. the accurately estimation of side force of tire is current technological difficulties, the automobile body deceleration coarse value estimation public affairs in the present invention Formula make use of wheel longitudinal force indirectly to estimate wheel lateral force, it is to avoid the directly estimation of side force of tire, improves system Computational accuracy.

Accompanying drawing explanation

Fig. 1 is the structural representation of longitudinal automobile speedestimate system of the present invention；

Detailed description of the invention

Below in conjunction with embodiment and accompanying drawing, technical scheme is further elaborated.

Embodiment 1

Present embodiments provide a kind of longitudinal automobile speedestimate method controlled for distributed type four-wheel-driven electrical vehicular power, its Being realized by longitudinal automobile speedestimate system, described longitudinal automobile speedestimate system includes: the rough estimation block of vehicle reference speed, car Body deceleration coarse value estimation block and Kalman filtering module；And comprise the following steps:

S10, the described rough estimation block of vehicle reference speed freely roll wheel speed according to motor speed and wheel speed estimation；Profit Freely roll wheel speed with yaw velocity and steering wheel angle signal by 4 and be converted to speed at vehicle centroid；Utilize vehicle matter Speed calculation vehicle reference speed coarse value at the heart；

In the present embodiment, following formula can be used to calculate and freely to roll wheel speed v_free,i:

$v_{free,i}=\frac{v_{w,i}\·C_{\mathrm{\λ},i}}{C_{\mathrm{\λ},i}-{\mathrm{\μ}}_i}---\left(1\right)$

$C_{\mathrm{\λ},i}=\frac{{\mathrm{\μ}}_i}{{\mathrm{\λ}}_{w,i}}---\left(2\right)$

In formula, v_w,iFor wheel speed, it can be calculated by the rotating speed of distributed motor, i.e. be multiplied by deceleration by motor speed Device speed ratio is multiplied by radius of wheel and is calculated, C_λ,iFor tire stiffness, λ_w,iFor wheel slip, μ_iAttachment coefficient, i=1,2,3, 4；When i is 1, represent the near front wheel；When i is 2, represent off-front wheel；When i is 3, represent left rear wheel；When i is 4, represent the right side Trailing wheel；Lower same.

And calculate speed v at vehicle centroid by following formula_x,i, i=1,2,3,4:

$v_{x,1}=\frac{v_{free,1}-\stackrel{\·}{\mathrm{\ψ}}\·l_a\·{\mathrm{sin\δ}}_f}{{\mathrm{cos\δ}}_f}-\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}-v_y\·{\mathrm{tan\δ}}_f---\left(3\right)$

$v_{x,2}=\frac{v_{free,2}-\stackrel{\·}{\mathrm{\ψ}}\·l_a\·{\mathrm{sin\δ}}_f}{{\mathrm{cos\δ}}_f}-\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}-v_y\·{\mathrm{tan\δ}}_f---\left(4\right)$

$v_{x,3}=v_{free,3}-\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}---\left(5\right)$

$v_{x,4}=v_{free,4}+\stackrel{\·}{\mathrm{\ψ}}\·\frac{t_w}{2}---\left(6\right)$

In formula,For yaw velocity, δ_fFor steering wheel angle, t_wFor wheelspan, l_aFor barycenter to front axle distance, v_yFor laterally Speed；

In the present embodiment, utilize speed calculation vehicle reference speed coarse value v at vehicle centroid_{x_raw}Can be real by following formula Existing:

$v_{x\_raw}=\underset{i=0}{\overset{3}{\Σ}}(k_i\·v_{x,i})/\underset{i=0}{\overset{3}{\Σ}}{k}_i$

In formula, k_iFor wheel stability sex factor.

S20, described vehicle body deceleration coarse value estimation block utilize Motor torque, brake pressure, motor speed or wheel Speed, yaw velocity and steering wheel angle signal estimation vehicle body deceleration coarse value；

In the present embodiment, described vehicle body deceleration coarse valueFollowing formula can be used to calculate:

${\hat{a}}_{x\_raw}=\frac{1}{m}\[(F_{x,1}+F_{x,2}){\mathrm{cos\δ}}_f+{\mathrm{\Δsin\δ}}_f+F_{x,3}+F_{x,4}+F_{wind}\]---\left(8\right)$

$F_{x,i}=\frac{1}{r_{w,i}}\[\frac{J_{w,i}}{r_{w,i}}\{a_{w,i}+{\mathrm{\ζ}}_1(v_{w,i}-{\hat{v}}_{w,i})\}+T_{b,i}-T_{d,i}\]---\left(9\right)$

$\mathrm{\Δ}=\frac{-(F_{x,1}+F_{x,2})\·(l_a+l_b){\mathrm{sin\δ}}_f+(F_{x,1}-F_{x,2})\·{\mathrm{cos\δ}}_f\·l_b+(F_{x,3}-F_{x,4})\·\frac{t_w}{2}-J_z\·\stackrel{\·\·}{\mathrm{\ψ}}-m\·{\stackrel{\·}{v}}_y\·l_b-m\·v_x\·\stackrel{\·}{\mathrm{\ψ}}\·l_b}{(l_a+l_b)\·{\mathrm{cos\δ}}_f}---\left(10\right)$

In formula, m is complete vehicle quality；F_windFor windage；F_x,iFor wheel longitudinal force, i=1,2,3,4；r_w,iFor radius of wheel； T_b,iFor brake force；T_d,iFor driving force, J_zFor vehicle around the rotary inertia of z-axis, l_bFor barycenter to rear axle distance；J_w,iTurn for wheel Dynamic inertia, i=1,2,3,4；a_w,iFor the acceleration of wheel, i=1,2,3,4；ζ₁For the estimation factor, obtained by look-up table； For estimating wheel speed, i=1,2,3,4；For yaw angle acceleration；For lateral car acceleration；v_xSpeed for the direction of advance of vehicle Degree.

S30, described Kalman filtering module utilize the ginseng that step S10 and S20 are calculated by steady-state Kalman filter Examine speed coarse value and vehicle body deceleration coarse value is filtered, estimate and export reference speed and automobile body deceleration.

Described Kalman filtering can be realized by following iteration:

${\hat{X}}_{n+1}=(\mathrm{\Φ}-K_{f}H){\hat{X}}_n+K_f{y}_n;$

In formula,

The sequencing of above example only for ease of describing, does not represent the quality of embodiment.

Last it is noted that above example is only in order to illustrate technical scheme, it is not intended to limit；Although With reference to previous embodiment, the present invention is described in detail, it will be understood by those within the art that: it still may be used So that the technical scheme described in foregoing embodiments to be modified, or wherein portion of techniques feature is carried out equivalent； And these amendment or replace, do not make appropriate technical solution essence depart from various embodiments of the present invention technical scheme spirit and Scope.

Claims (5)

1. one kind for distributed type four-wheel-driven electrical vehicular power control longitudinal automobile speedestimate method, it is characterised in that include with Lower step:

S10, the described rough estimation block of vehicle reference speed freely roll wheel speed according to motor speed and wheel speed estimation；Utilize horizontal stroke Pivot angle speed and steering wheel angle signal freely roll wheel speed by 4 and are converted to speed at vehicle centroid；Utilize at vehicle centroid Speed calculation vehicle reference speed coarse value；

S20, described vehicle body deceleration coarse value estimation block utilize Motor torque, brake pressure, motor speed or wheel speed, horizontal stroke Pivot angle speed and steering wheel angle signal estimation vehicle body deceleration coarse value；

S30, described Kalman filtering module utilize the reference car that step S10 and S20 are calculated by steady-state Kalman filter Speed coarse value and vehicle body deceleration coarse value are filtered, and estimate and export reference speed and automobile body deceleration.

The longitudinal automobile speedestimate method controlled for distributed type four-wheel-driven electrical vehicular power the most according to claim 1, its It is characterised by, uses following formula to calculate and freely roll wheel speed v_free,i:

In formula, v_w,iFor wheel speed, C_λ,iFor tire stiffness, λ_w,iFor wheel slip, μ_iAttachment coefficient, i=1,2,3,4.

The longitudinal automobile speedestimate method controlled for distributed type four-wheel-driven electrical vehicular power the most according to claim 2, its It is characterised by, calculates speed v at vehicle centroid by following formula_x,i, i=1,2,3,4:

In formula,For yaw velocity, δ_fFor steering wheel angle, t_wFor wheelspan, l_aFor barycenter to front axle distance, v_yFor lateral car Speed.

The longitudinal automobile speedestimate method controlled for distributed type four-wheel-driven electrical vehicular power the most according to claim 3, its It is characterised by, utilizes speed calculation vehicle reference speed coarse value v at vehicle centroid_{x_raw}Realized by following formula:

In formula, k_iFor wheel stability sex factor.

The longitudinal automobile speedestimate method controlled for distributed type four-wheel-driven electrical vehicular power the most according to claim 4, its It is characterised by, described vehicle body deceleration coarse valueFollowing formula can be used to calculate:

In formula, m is complete vehicle quality；F_windFor windage；F_x,iFor wheel longitudinal force, i=1,2,3,4；r_w,iFor radius of wheel；T_b,iFor Brake force；T_d,iFor driving force, J_zFor vehicle around the rotary inertia of z-axis, l_bFor barycenter to rear axle distance；J_w,iIt is used to for vehicle wheel rotation Amount, i=1,2,3,4；a_w,iFor the acceleration of wheel, i=1,2,3,4；ζ₁For the estimation factor, obtained by look-up table；For estimating Calculation wheel speed, i=1,2,3,4；For yaw angle acceleration；For lateral car acceleration；v_xSpeed for the direction of advance of vehicle.