Process for controlling driving dynamics of a street vehicle

• US 6,223,114 B1
• Filed: 03/22/1999
• Issued: 04/24/2001
• Est. Priority Date: 03/20/1998
• Status: Expired due to Term

• Current Assignee: 21ST CENTURY GARAGE LLC
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Hamann, Dieter, Maurath, Rudolf, Pressel, Joachim, Boros, Imre, Reiner, Michael
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): MANCHO, RONNIE M
• Application Number:
  US09/273,760
• Time in Patent Office: 764 Days
• Field of Search: 701/70, 701/1, 701/36, 701/41, 701/72, 701/50, 701/53, 701/55, 701/79
• US Class Current: 701/70
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• CPC Class Codes: B60T 8/1708 for lorries or tractor-trailer combinations
• CPC Class Codes: B60T 8/17552 responsive to the tire sideslip angle or the vehicle body slip angle

Abstract

For regulating the driving dynamics of a road vehicle, setpoints for the yaw rate {dot over (Ψ)} and the float angle β of the vehicle are generated continuously by evaluating a simulation computer implemented vehicle model. The simulation computer generates control signals for activating at least one wheel brake of the vehicle based on a comparison of the reference values {dot over (Ψ)}_SO as a setpoint, and the actual values {dot over (Ψ)}_I of the yaw rate continuously recorded by a yaw rate sensor. The vehicle model is represented by a linear differential equation system of the form [P]·({overscore ({dot over (X)})})=[Q]·({overscore (X)})+({overscore (C)})·δ(t). The driving-dynamic state values β_Z(k−1) and {dot over (Ψ)}_Z(k−1) are updated at a point in time t(k−1), followed by a point in time t(k) that is later by a clock time interval T_K, by evaluation of the system of equations $X\left(k\right)={\{}_{T_k}-\left[Q\right]\}·{\{}_{T_k}·X\left(k-1\right)+C·\delta \left(k\right)\}$

with the values of the matrix elements p_ij and q_ij updated for that point in time T_K.

Claims

1. A method for driving dynamic regulation of a road vehicle in which reference values for at least a yaw rate {dot over (Ψ

)} and a float angle β

of the vehicle are generated, under clock control in sequential cycles of a presettable duration T_K, by a simulation computer in an electronic control unit which automatically regulates driving dynamics of the vehicle based on a model that represents the vehicle in terms of design and load state parameters thereof, and based on operating data which includes measured current values of steering angle δ and

vehicle speed v_x, said simulation computer generating control signals for activating at least one wheel brake of the vehicle based on a comparison of a reference value {dot over (Ψ

)}_SO as a setpoint for the yaw rate of the vehicle and actual values {dot over (Ψ

)}_I of the yaw rate of the vehicle that are continuously recorded a yaw rate sensor device, or for reducing an engine drive torque of the vehicle;

wherein

the vehicle model is implemented by a linear differential equation system of the form

2. The method according to claim 1, wherein:

the road vehicle includes a tractor; and

a float angle β

_Z at a low constant speed of the tractor, is also checked by evaluating a relationship ${\mathrm{\beta <br><br>}}_z=\mathrm{\delta <br><br>}·<br><br>\frac{1_H}{1_z}.$

3. The method according to claim 1 wherein:

the road vehicle includes a tractor; and

the float angle β

_Z of the tractor is also obtained by evaluating a relationship ${\mathrm{\beta <br><br>}}_z={\int <br><br>}_{t_{0<br><br>\left(\mathrm{\delta <br><br>}=0\right)}}^{t_{c<br><br>\left(\mathrm{\delta <br><br>}={\mathrm{\delta <br><br>}}_c\right)}}<br><br>\left(\frac{a_q}{v}-\stackrel{.}{\mathrm{\Psi <br><br>}}\right)<br><br>\text{\hspace{1em}<br><br>}<br><br><br><br>t$

for an integration time interval t_i=t_c−

t₀, within which a driver of the tractor sets a steering angle δ

required for rounding a curve with a_q being transverse acceleration of the vehicle.

4. The method according to claim 1, wherein:

the road vehicle comprises a tractor and a semitrailer connected to the tractor;

zero elements p₁₁, p₂₁, p₃₁, p₃₃, p₄₁, p₄₃, and p₄₄ of the matrix [P_Z] representing the tractor alone for driving-dynamic acquisition of state values β

_A (float angle) and {dot over (Ψ

)}_A (yaw rate) of the semitrailer are replaced by elements p₁₁=m_A V, p₂₁=m_Av1_G, p₃₁=m_Avl_AV, p₃₃=J_A, p₄₁=1, p₄₃=1_AV/v, and p₄₄=l_G/v;

zero elements q₁₁, q₁₃, q₂₁, q₂₃, q₃₁, q₃₃, and q₄₃ of the matrix [Q] representing the tractor alone, are replaced by matrix elements q₁₁=−

C_A, q₁₃=−

m_Av+C_A1_AH/v, q₂₁=C_A1_G, q₂₃=m_Avl<sub>G−

CA</sub>1_G1_AH/v, q₃₁=C_A1_AV+C_A1_AH, q₃₃=m_Avl_AV−

(C_A1_AV1_AH+C_A1_AH²)/v and q₄₃=−

1; and

state vector {overscore (X)} and its time derivation {overscore ({dot over (X)})} are supplemented by components x₁=β

_A and x₃={dot over (Ψ

)}_A as well as {dot over (x)}₁={dot over (β

)}_A and {dot over (x)}₃={umlaut over (Ψ

)}_A, where m_A is mass of the semitrailer, l_G is distance of the fifth wheel measured in the lengthwise direction of the vehicle from a center of gravity of the tractor, l_AV is a distance of a center of gravity of the semitrailer from a fifth wheel of the vehicle, l_AH is a distance of a semitrailer center of gravity from an axis of the fifth wheel, C_A represents diagonal travel stiffness and J_A represents a yaw moment of inertia of semitrailer.

5. The method according to claim 1 for a tractor-trailer unit with a two-axle tractor and a one-axle semitrailer, wherein:

a float angle β

_A of semitrailer is obtained by evaluation of a relationship ${\mathrm{\beta <br><br>}}_A=\mathrm{\varphi <br><br>}+{\mathrm{\beta <br><br>}}_z-\frac{\stackrel{.}{\mathrm{\Psi <br><br>}}<br><br>\left(1_G+1_{\mathrm{AV}}\right)}{v}$

in which φ

represents a kink angle that increases inversely with a value of steering angle δ

, said kink angle being enclosed by lengthwise central planes of the tractor and the semitrailer that intersect at a fifth wheel of tractor-trailer unit.

6. The method according to claim 5, wherein the kink angle φ

is obtained by evaluating a relationship $\mathrm{\varphi <br><br>}=180<br><br>\mathrm{°<br><br>}-\arccos <br><br>\left(\stackrel{1_A}{\sqrt{R_A^2+1_A^2}}\right)-\arccos <br><br>\left(\frac{R_A^2-R_v^2+1_v^2-1_A^2}{2·<br><br>1_v<br><br>\sqrt{R_A^2+1_a^2}}\right)$

in which R_V represents an average curved path radius of front wheels of the tractor and R_A represents an average curved path radius of wheels of semitrailer, with R_V and R_A being provided by a relationship $R_{V,A}=\frac{b_{\mathrm{spur}<br><br>\text{\hspace{1em}<br><br>}<br><br>V,A}·<br><br>v_{\mathrm{Achse}<br><br>\text{\hspace{1em}<br><br>}<br><br>V,A}}{{\left(v_{\mathrm{Rl}}-v_{\mathrm{Rr}}\right)}_{V,A}}$

in which b_spurV,A represents track widths at a front axle of the tractor (b_spurV) and at a semitrailer axis (b_spurA), v_Rl and V_Rr represent wheel circumferential velocities at left and right wheels of the respective vehicle axles, and v_AchseV,A refers to respective algebraic average wheel speeds.

7. The method according to claim 1 for a tractor-trailer unit with a two-axle tractor and a single-axle semitrailer, wherein at least one of diagonal travel stiffnesses C_V and C_H of wheels of the tractor and diagonal travel rigidity C_A of the wheels of semitrailer during steady-state rounding of a curve by the tractor or the tractor-trailer unit, are determined by evaluating the following relationships:

$\begin{array}{c}0=\text{\hspace{1em}<br><br>}<br><br>\left(C_H<br><br>1_H-C_v<br><br>1_v\right)<br><br>{\mathrm{\beta <br><br>}}_z-\left(\frac{C_v<br><br>1_v^2+C_H<br><br>1_H^2}{v}\right)<br><br>\stackrel{.}{\mathrm{\Psi <br><br>}}+\\ \text{\hspace{1em}<br><br>}<br><br>C_A<br><br>1_G<br><br>{\mathrm{\beta <br><br>}}_A+\left(m_A<br><br>{\mathrm{v1}}_G-\frac{C_A<br><br>1_{\mathrm{AH}}<br><br>1_G}{v}\right)<br><br>\stackrel{.}{\mathrm{\Psi <br><br>}}+C_v<br><br>1_v<br><br>\mathrm{\delta <br><br>}\end{array}$$\begin{array}{c}0=\text{\hspace{1em}<br><br>}<br><br>\left(C_H<br><br>1_H-C_v<br><br>1_v\right)<br><br>{\mathrm{\beta <br><br>}}_z-\left(\frac{C_v<br><br>1_v^2+C_H<br><br>1_H^2}{\text{\hspace{1em}<br><br>}}\right)<br><br>\stackrel{.}{\mathrm{\Psi <br><br>}}+\\ \text{\hspace{1em}<br><br>}<br><br>C_A<br><br>1_G<br><br>{\mathrm{\beta <br><br>}}_A+\left(m_A<br><br>{\mathrm{v1}}_G-\frac{C_A<br><br>1_{\mathrm{AH}}<br><br>1_G}{v}\right)<br><br>\stackrel{.}{\mathrm{\Psi <br><br>}}+C_v<br><br>1_v<br><br>\mathrm{\delta <br><br>}\end{array}$$0=C_A<br><br>\left(1_{\mathrm{AV}}+1_{\mathrm{AH}}\right)·<br><br>{\mathrm{\beta <br><br>}}_A+\left(m_A<br><br>{\mathrm{v1}}_{\mathrm{AV}}-\frac{C_A<br><br>1_{\mathrm{AH}}<br><br>\left(1_{\mathrm{AV}}+1_{\mathrm{AH}}\right)}{v}\right)<br><br>\stackrel{.}{\mathrm{\Psi <br><br>}}.$

in which {dot over (Ψ

)} represents an identical yaw rate for the tractor and semitrailer.

8. A device for driving dynamic regulation of a road vehicle whose wheel brake are controlled by output signals from an electronic control unit, both in response to a driver'"'"'s input command to decelerate the vehicle by actuating a set value transducer, and also by way of maintaining a dynamically stable driving behavior, said wheel brakes being actuatable individually or together so that deviations of a yaw rate {dot over (Ψ

)}, for which a yaw rate sensor is provided and which can be controlled when rounding a curve by specifying a steering angle δ

, can be compensated by a setpoint obtained from a steering angle specification and measured vehicle speed, by way of an approximation of the setpoint, with a simulation computer being provided for setting the setpoint based on a vehicle model in which the vehicle is defined by design-related values, a load state, and operating data, and based on measured values of at least steering angle δ and

vehicle lengthwise velocity v_x, said simulation computer generating reference values for at least a yaw rate {dot over (Ψ

)} of the vehicle, and being designed for a clock-controlled evaluation of motion equations of a tractor-trailer unit as a vehicle reference model and also of motion equations of a two-axle motor vehicle, wherein said simulation computer comprises a computer readable memory encoded with;

routines to be implemented by the electronic control unit, for adaptive determination of selected values from parameters (n_Vl, n_Vr, n_Hl, n_Hr, n_Al, n_Ar, M_mot, P_VA, and P_HA) that can be measured while driving the vehicle or a unit consisting of the vehicle as a tractor and trailer, said selected values being

a) total mass m_ges of the tractor-trailer unit

b) mass m_z of the tractor

c) mass m_A of the trailer

d) wheelbase l_Z of the tractor

e) axle load distribution P_VA/P_HA of the tractor, and

f) axle load distribution of the tractor-trailer unit and/or the rear axle load P_A of the trailer; and

routines to be implemented by the electronic control unit, for estimating the following

g) a moment of inertia J_Z of the tractor around a vertical axis thereof, and

h) a moment of inertia J_A of the trailer around its vertical axis.

9. The device according to claim 8 wherein

at least one of mass m_Z of the tractor and mass_ges of the tractor-trailer unit are determined by an evaluation of a relationship $m_{Z,\mathrm{ges}}=\frac{M_{\mathrm{mot}}·\; <li></li>\frac{n_{\mathrm{mot}}}{v}·<br><br>\mathrm{\eta <br><br>}}{\left(Z_{\mathrm{HSP}}-Z_{\mathrm{ist}}\right)·<br><br>v}$

in which M_mot represents engine output torque, n_mot represents engine rpm, v represents vehicle speed, η

represents total efficiency of a front wheel drive transmission line of the tractor characterized by a dimensionless number <

1, Z_HSP which represents a vehicle deceleration that takes place in an up-shift phase in which a vehicle operator engages a gear that corresponds to a lower engine rpm, and Z_ist represents an acceleration that takes place during acceleration of the vehicle that occurs after a gear change, with a mass m_A of the trailer being determined by evaluating relationship m_A=m_ges−

m_Z.

10. The device according to claim 8 wherein the electronic control unit uses output signals from wheel rpm sensors assigned individually to the wheels of the tractor to determine the wheelbase l_z of the tractor according to relationship $1_z=\sqrt{R_v^2-R_H^2}$

in which R_V and R_H represent average road radii determined during steady-state rounding of a curve and moderate vehicle speed according to relationship $R_{V,H}=\frac{b_{V,H}·}{}$

(vV,Hl+vV,Hr)(vV,Hl+vV,Hr)·

2

for the front and rear wheels of the tractor, with b_V,H representing wheelbases b_V and b_H at front and rear axles of the tractor and V_V,Hl and v_V,Hr being wheel speeds of left and right front and rear wheels of the tractor.

11. The device according to claim 8 wherein the electronic control unit determines the wheelbase l_Z of the tractor by evaluating a relationship $1_z=\frac{\delta }{}$

Ψ

.z·

vz.

12. The device according to claim 8 for a tractor-trailer unit in which each vehicle wheel has a wheel rpm sensor, wherein

an electronic or electromechanical kink angle sensor is provided for detecting an angle φ

at which respective vertical lengthwise central planes of the tractor and the trailer of the tractor-trailer unit intersect at its fifth wheel when the tractor-trailer unit is rounding a curve; and

the electronic control unit determines a length l_A between the fifth wheel and an axle of the trailer, by evaluating a relationship $1_A=\frac{R_H-R_A<br><br>\sqrt{1+{\tan }^2}<br><br>\mathrm{\varphi <br><br>}}{\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\varphi <br><br>}}+R_A<br><br>\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\varphi <br><br>}$

in which R_H and R_A are average road radii R_H,A of rear wheels of the tractor and wheels of the trailer axle, which in turn can be determined by relationship $R_{H,A}=\frac{b_{H,A}<br><br>\left(v_{H,\mathrm{Al}}+v_{H,\mathrm{Ar}}\right)}{\left(v_{H,\mathrm{Al}}+v_{H,\mathrm{Ar}}\right)·<br><br>2}$

in which b_H,A represents wheel bases b_H and b_A of rear axles of the tractor and the semitrailer.

13. The device according to claim 12, wherein the electronic control unit determines a length l_SH between the fifth wheel and a rear axle of tractor by evaluating a relationship $1_{\mathrm{SH}}=\frac{R_H-R_A}{}$

tan2

ϕ

+1tan

 



ϕ

.

14. The device according to claim 8 wherein the tractor has at least one axle load sensor which generates an electrical output signal that can be processed by the electronic control unit, said signal being a measure of a load supported on the road by a vehicle axle whose load is monitored.

15. The device according to claim 14 wherein the electronic control unit determines a distance l_V between a center of gravity of the tractor and a front axle of the tractor according to a relationship $1_v=1_z·$

PHAmz

when the at least one axle load sensor is associated with the rear axle of the vehicles, and determines this distance l_V by a relationship $1_v=1_z·<br><br>\left(1-\frac{P_{V<br><br>\text{\hspace{1em}<br><br>}<br><br>A}}{m_z}\right)$

when the at least one axle load sensor is associated with the front axle of the vehicle.

16. The device according to claim 8 wherein:

the tractor-trailer unit has a trailer equipped with an axle load sensor which generates an electrical output signal that is characteristic of a load P_AHA supported by a trailer axle on the road, and can be processed by the electronic control unit; and

the electronic control unit determines a distance l_AV between a center of gravity of the trailer and the fifth wheel according to a relationship $1_{\mathrm{AV}}=1_A·<br><br>\frac{P_{\mathrm{HA}}}{m_A}$

in which l_A represents distance of a vertical trailer axis from the fifth wheel, and m_A represents mass of the trailer.

17. The device according to claim 8 wherein:

the tractor-trailer unit has a tractor equipped with an axle load sensor that generates an electrical output signal that characterizes mass m_ZHA supported by a rear axle of the tractor on the road, and can be processed by electronic control unit; and

the electronic control unit determines a distance l_AV between a center of gravity of the trailer and the fifth wheel according to a relationship $1_{\mathrm{AV}}=1_A·<br><br>\left(1-\frac{\left(m_{\mathrm{ZHA}}-m_{\mathrm{ZHAleer}}\right)}{m_A}\right)·<br><br>\frac{1_Z}{1_{\mathrm{SV}}}$

in which m_ZHAleer represents mass supported by the rear axle of the tractor without the semitrailer, m_A represents mass of the trailer, and l_SV represents a distance between the fifth wheel and a front axle of the tractor.

18. The device according to claim 8 wherein:

the tractor-trailer unit is equipped with a sensor that generates an electrical output signal that is characteristic of a mass share m_AS of trailer supported on the tractor at the fifth wheel, and can be processed by the electronic control unit; and

the electronic control unit determines a distance l_AV between the center of gravity of the semitrailer and the fifth wheel according to relationship $1_{\mathrm{AV}}=1_A·<br><br>\left(1-\frac{m_{\mathrm{AS}}}{m_A}\right).$

19. The device according to claim 8 wherein the electronic control unit estimates a yaw moment of inertia J_Z of the tractor and a yaw moment of inertia J_A of the trailer according to relationship

20. The device according to claim 14 for a truck or a tractor-trailer or towed trailer unit, equipped with air suspension, wherein axle load sensing is implemented by sensing pressure in suspension apparatus at a vehicle axle that is monitored.

21. The device according to claim 8 wherein the electronic control unit determines a rear axle load P_HA of the tractor in a braking mode in which, with moderate vehicle deceleration, only rear wheel brakes are actuated by evaluating a relationship $P_{\mathrm{HA}}=\frac{m_{z,\mathrm{ges}}·}{}$

kHA·

Zλ

HA

in which Z represents measured vehicle deceleration and λ

_HA represents brake slip determined by a relationship ${\mathrm{\lambda <br><br>}}_{\mathrm{HA}}=\frac{n_{V<br><br>\text{\hspace{1em}<br><br>}<br><br>A}-n_{\mathrm{HA}}}{n_{V<br><br>\text{\hspace{1em}<br><br>}<br><br>A}}<br><br>\left[\%\right]$

and k_HA is a tire constant that corresponds to a ratio λ

/μ

of an adhesion coefficient μ

to brake slip λ

produced by brake actuation, and assuming equal wheel diameters of the front and rear wheels, n_VA represents wheel rpm values of non-braked wheels, and n_HA represents wheel rpms of braked wheels of tractor.

22. The device according to claim 21 wherein the electronic control unit determines a front axle load P_VA of tractor-trailer unit by evaluating a relationship $P_{V}$

 



A=kV

 



A·

fMZ·

a·

PHAkHA

in which k_VA represents at least one tire constant of front wheels of the tractor, f_MZ represents a design ratio of front wheel and rear wheel brakes that corresponds to a ratio B_VA/B_HA of front axle braking force B_VA and rear axle braking force B_HA, when all the wheel brakes are controlled with equal control pressure; and

a represents an actuating pressure ratio P_VA/P_HA that results when, during a brake application, all braked vehicle wheels are regulated to an equal current velocity by regulating a braking force distribution.

23. The device according to claim 21 wherein an adaptive determination of tire constants k_VAl and k_VAr of left and right front wheels of the tractor and tire constants k_HAl and k_HAr of left and right rear wheels is obtained by an evaluation of relationships $k_{\mathrm{VAl},r}=\frac{{\lambda }_{}}{}$

VAl,r·

PVA2·

Z·

mz

and $k_{\mathrm{HAl},r}=\frac{{\mathrm{\lambda <br><br>}}_{\mathrm{HAl},r}·<br><br>P_{\mathrm{HA}}}{2·<br><br>Z·<br><br>m_z}$

for brake applications with a moderate vehicle deceleration.

24. The device according to claim 23 wherein the tire constants k_VAl,r and k_HAl,r are determined in alternating cycles in which tire constants k_VAl and k_HAr and k_VAr and k_HAl of one front wheel and of the rear wheel of the tractor located diagonally opposite the front wheel are determined.

25. The device according to claim 8 in a vehicle provided with a regulating device that regulates a ratio $\Phi$

=BVABHA

of front axle braking force B_VA to rear axle braking force B_HA according to a relationship

26. The device especially according to claim 8 for a tractor-trailer unit designed as a towing vehicle with at least one trailer wherein both the tractor and the at least one trailer are equipped with a yaw angle sensor.