Control system and method for controlling the driving-away manoeuvre in a motor vehicle with a servo-controlled gearbox

• US 7,702,445 B2
• Filed: 06/08/2006
• Issued: 04/20/2010
• Est. Priority Date: 06/17/2005
• Status: Active Grant

• Current Assignee: C.R.F. Societa Consortile Per Azioni
• Original Assignee: Cefla Societa' Cooperativa
• Inventors: Gianoglio, Renato, Ellena, Giovanni, Porta, Attilio, Lupo, Massimo, Borodani, Pandeli, Del Pin, Dario, Fossanetti, Massimo
• Primary Examiner(s): Zanelli; Michael J.
• Application Number:
  US11/449,233
• Publication Number:
  US 20060287794A1
• Time in Patent Office: 1,412 Days
• Field of Search: None
• US Class Current: 701/67
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2510/1015 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/18027 Drive off, accelerating from standstill
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

What is described is a control system for controlling the driving-away maneuver in a motor vehicle provided with a gearbox comprising a primary input shaft which can be coupled to a drive shaft of a propulsion system of the vehicle by means of a servo-assisted friction clutch, wherein a control unit receives at its input signals indicating a command imparted by the driver of the motor vehicle by operating the accelerator pedal, and generates—on the basis of a mathematical reference model—reference torque request signals indicating the reference torques requested from the drive shaft and from the friction clutch during the driving-away manoeuvre, and also generates—by comparison between signals indicating the estimated angular velocities of the drive shaft and of the primary gear shaft, and detected signals indicating the actual angular velocities of the drive shaft and of the primary gear shaft—corresponding corrective contributions, in such a way as to construct command signals for controlling torque actuator devices of the propulsion system and of the friction clutch, for controlling the driving-away manoeuvre in the motor vehicle.

Claims

1. Control system for controlling a driving-away manoeuvre in a motor vehicle provided with a gearbox comprising a primary input shaft adapted to be coupled to a drive shaft of a propulsion system of the vehicle by means of a servo-assisted friction clutch,

comprising:

an electronic processing assembly adapted to receive at their inputs signals or data indicating a command imparted by the driver of the motor vehicle by the operation of the accelerator pedal, and arranged for generating command signals or data designed to control torque actuator devices of the propulsion system and of the friction clutch, for the control of the driving-away manoeuvre in the motor vehicle; and

memory devices, associated with the said processing assembly and storing data and/or instructions representing a mathematical reference model for the calculation of the aforesaid command signals,

the processing assembly including;

a reference torque generator module arranged for generating, on the basis of the signals or data indicating the command imparted by the driver by the operation of the accelerator pedal and of the reference model, reference torque request signals or data indicating a reference torque requested from the drive shaft and a reference torque requested from the friction clutch in the course of the driving-away manoeuvre;

an estimator module, arranged for calculating, on the basis of the reference torque request signals or data and on the basis of the reference model, signals or data indicating the angular velocities of the drive shaft and of the gearbox primary input shaft in the course of the driving-away manoeuvre; and

a controller module, arranged for calculating, on the basis of the signals or data indicating the angular velocities of the drive shaft and of the primary input shaft calculated by the estimator module, and on the basis of detected signals or data indicating the actual angular velocities of the drive shaft and of the primary input shaft, corrective contributions to the said reference torque request signals or data,

whereby the said torque request signals or data, as modified by the corresponding corrective contributions, form the command signals or data for the torque actuator devices.

2. System according to claim 1, in which the said signals or data indicating the command imparted by the driver by the operation of the accelerator pedal include a signal or datum indicating the position of the accelerator pedal.

3. System according to claim 2, in which the said signals or data indicating the command imparted by the driver by the operation of the accelerator pedal include a signal or datum indicating the requested variation of longitudinal acceleration of the vehicle, determined as a function of the signal or datum indicating the position of the accelerator pedal on the basis of a predetermined first relation model.

4. System according to claim 3, in which the said signals or data indicating the command imparted by the driver by the operation of the accelerator pedal include a signal or datum indicating the requested driving-away torque, determined as a function of the signal or datum indicating the position of the accelerator pedal on the basis of a predetermined second relation model.

5. System according to claim 4, in which the said signals or data indicating the command imparted by the driver by the operation of the accelerator pedal include a signal or datum indicating the angular velocity of the drive shaft requested during driving away, determined as a function of the signal or datum indicating the position of the accelerator pedal on the basis of a predetermined third relation model.

6. System according to claim 5, in which the said first relation model associates the signal or datum indicating the position of the accelerator pedal with a signal or datum indicating the variation of longitudinal acceleration of the vehicle which is constant over time at least during a first stage of the driving-away manoeuvre, and the said reference torque request signal indicating the reference torque requested from the friction clutch has a linear temporal variation in the form of a ramp in a first stage of the driving-away manoeuvre, the gradient of which is proportional to the value of the said signal or datum indicating the variation of the longitudinal acceleration.

7. System according to claim 6, in which the said reference torque request signal indicating the reference torque requested from the drive shaft has a linear temporal variation in the form of a ramp in a first stage of the driving-away manoeuvre, the gradient of which is a function of the angular velocity of the drive shaft requested on driving away and of the gradient of the temporal variation ramp of the signal indicating the reference torque requested from the friction clutch, and is greater than the gradient of the temporal variation ramp of the signal indicating the reference torque requested from the friction clutch.

8. System according to claim 7, in which the said reference torque request signals indicating the reference torque requested from the drive shaft and the reference torque requested from the friction clutch have a constant value over time in an intermediate stage of the driving-away manoeuvre, and the said reference torque request signal driving-away manoeuvre indicating the reference torque requested from the driver shaft has a linear temporal variation in the form of a slope in a final stage of the driving-away manoeuvre, from the instant at which the difference between the angular velocities of the drive shaft and of the gearbox primary input shaft calculated by the estimator module is less than a predetermined threshold value.

9. System according to claim 8, in which the reference torque request signal indicating the reference torque requested from the friction clutch has the following temporal variation:

C_FRif(t)=C_F0+dC_f·

t for t₀≦

t≦

t₂

C_Frif(t)=C_Fsteady for t₂<

t≦

t₄

where

C_F0 is the initial value of the torque, at time t₀

C_F0=C_F(t₀);

dC_F is the gradient of the temporal variation ramp, calculated as

${\mathrm{dC}}_F=K_{\mathrm{Jerk}}·<br><br>{\mathrm{jerk}}^{*}<br><br>\left[\mathrm{Nm}/\sec \right]$ $\mathrm{in}<br><br><br><br>\mathrm{which}$ $K_{\mathrm{Jerk}}=\frac{J_P·<br><br>\mathrm{\tau <br><br>}}{R}$

where J_P is the total moment of inertia transferred to the primary shaft, τ

is the selected transmission ratio and R is the rolling radius of the wheels; and

C_FSteady is a value of intermediate steady torque, defined as

$C_{\mathrm{FSteady}}=K_{\mathrm{MSteady}}·<br><br>C_{\mathrm{Driver}}$ $\mathrm{in}<br><br><br><br>\mathrm{which}$ $K_{\mathrm{MSteady}}=\frac{J_P}{J_M+J_P}$

where J_M is the total moment of inertia of the engine and C_Driver is the reference steady torque for the clutch at the end of the driving-away manoeuvre;

and

the reference torque request signal indicating the reference torque requested from the drive shaft has the following temporal variation;

C_MRif(t)=C_M0+dC_M·

t for t₀≦

t≦

t₁

C_MRif(t)=C_Msteady for t₁<

t≦

t₃

C_Mrif(t)=C_Msteady+dC_MC1·

t for t₃<

t≦

t₄

where;

C_M0 is the initial value of the torque, at time t₀

C_M0=C_M(t₀);

dC_M is the gradient of the temporal variation ramp, calculated as

${\mathrm{dC}}_M=\frac{1}{\left(\frac{1}{{\mathrm{dC}}_F}-\frac{2·<br><br>\left({\mathrm{\omega <br><br>}}_{\mathrm{Msp}}-{\mathrm{\omega <br><br>}}_{M<br><br><br><br>0}\right)·<br><br>J_M}{{\left(C_{\mathrm{MSteady}}-C_{M<br><br><br><br>0}\right)}^2}\right)}$

in which ω

_M0 is the initial value of the rotation speed of the engine, at time t₀

ω

_M0=ω

_M(t₀), and

C_MSteady is a value of intermediate steady torque, defined as

$C_{\mathrm{MSteady}}=K_{\mathrm{MSteady}}·<br><br>C_{\mathrm{Driver}}$ $\mathrm{where}$ $K_{\mathrm{MSteady}}=\frac{J_P}{J_M+J_P}$

and C_Driver is the reference steady torque for the engine at the end of the driving-away manoeuvre; and

dC_MCI is the gradient of the temporal variation ramp in a terminal stage for inertia compensation, defined as;

${\mathrm{dC}}_{\mathrm{MC}<br><br><br><br>1}=\frac{C_{\mathrm{Driver}}-C_{\mathrm{MSteady}}}{2·<br><br>\left(J_M+J_P\right)·<br><br>{\mathrm{\Delta <br><br>\omega <br><br>}}_{C<br><br><br><br>1}}·<br><br>C_{\mathrm{Driver}}$

in which Δ

ω

_CI is a threshold value of difference between the angular velocities of the drive shaft and of the gearbox primary input shaft calculated by the estimator module,

the said inertia compensation stage being adapted to ensure the synchronization of the angular velocities of the drive shaft and of the primary input shaft in such a way as to avoid discontinuities in the acceleration of the vehicle due to the variations of the equivalent moment of inertia of the system following the engagement of the friction clutch.

10. System according to any one of the preceding claims, in which the said processing assembly comprises separate control units for the engine and for the gearbox, coupled to corresponding memory devices and connected to a common transmission line, and adapted to be interfaced with corresponding torque actuators of the propulsion system and of the friction clutch, the engine control unit controlling the torque actuator devices of the propulsion system as a function of the torque request signal generated by the gearbox control unit.

11. System according to any one of claims 1 to 9, in which the said processing assembly comprises a single integrated electronic control unit, coupled to a memory device, and adapted to be interfaced with torque actuator devices of the propulsion system and of the friction clutch.

12. Control method for controlling a driving-away manoeuvre in a motor vehicle provided with a gearbox comprising a primary input shaft which can be coupled to a drive shaft of a propulsion system of the vehicle by means of a servo-assisted friction clutch,

comprising the following operations:

a) generating, on the basis of signals or data indicating a command imparted by the driver by the operation of the accelerator pedal and on the basis of a mathematical reference model, reference torque request signals or data indicating a reference torque requested from the drive shaft and a reference torque requested from the friction clutch in the course of the driving-away manoeuvre;

b) estimating, on the basis of the reference torque request signals or data and on the basis of the reference model, signals or data indicating the angular velocities of the drive shaft and of the gearbox primary input shaft in the course of the driving-away manoeuvre; and

c) determining, on the basis of the signals or data indicating the estimated angular velocities of the drive shaft and of the primary input shaft, and on the basis of detected signals or data indicating the actual angular velocities of the drive shaft and of the primary input shaft, corrective contributions to the said reference torque request signals or data,

the said torque request signals or data, as modified by the corresponding corrective contributions, forming command signals or data for the control of torque actuator devices of the propulsion system and of the friction clutch, for the control of the driving-away manoeuvre in the motor vehicle.

13. Method according to claim 12, comprising the detection of a signal or datum indicating the position of the accelerator pedal following the command imparted by the driver by the operation of the accelerator pedal.

14. Method according to claim 13, comprising the determination of a signal or datum indicating the variation of longitudinal acceleration of the vehicle requested by means of the command imparted by the driver, as a function of the signal or datum indicating the position of the accelerator pedal, on the basis of a predetermined first relation model.

15. Method according to claim 14, comprising the determination of a signal or datum indicating the driving-away torque requested by means of the command imparted by the driver, as a function of the signal or datum indicating the position of the accelerator pedal, on the basis of a predetermined second relation model.

16. Method according to claim 15, comprising the determination of a signal or datum indicating the angular velocity of the drive shaft torque requested on driving away, as a function of the signal or datum indicating the position of the accelerator pedal, on the basis of a predetermined third relation model.

17. Method according to claim 16, in which the said first relation model associates the signal or datum indicating the position of the accelerator pedal with a signal or datum element indicating the variation of longitudinal acceleration of the vehicle which is constant over time at least during a first stage of the driving-away manoeuvre, and the reference torque request signal indicating the reference torque requested from the friction clutch has a linear temporal variation in the form of a ramp in a first stage of the driving-away manoeuvre, the gradient of which is proportional to the value of the said signal or datum indicating the variation of the longitudinal acceleration.

18. Method according to claim 17, in which the said reference torque request signal indicating the reference torque requested from the drive shaft has a linear temporal variation in the form of a ramp in a first stage of the driving-away manoeuvre, the gradient of which is a function of the angular velocity of the drive shaft requested on driving away and of the gradient of the temporal variation ramp of the signal indicating the reference torque requested from the friction clutch, and is greater than the gradient of the tern oral variation ram of the signal indicating the reference torque requested from the friction clutch.

19. Method according to claim 18, in which the said reference torque request signals indicating the reference torque requested from the drive shaft and the reference torque requested from the friction clutch have a constant value over time in an intermediate stage of the driving-away manoeuvre, and the said reference torque request signal indicating the reference torque requested from the drive shaft has a linear temporal variation in the form of a ramp in a terminal stage of the driving-away manoeuvre, from the instant at which the difference between the angular velocities of the drive shaft and of the gearbox primary input shaft calculated by the estimator module is less than a predetermined threshold value.

20. Method according to claim 19, in which the reference torque request signal indicating the reference torque requested from the friction clutch has the following temporal variation:

C_Frif(t)=C_F0+dC_F·

t for t₀≦

t≦

t₂

C_FRif(t)=C_Fsteady for t₂<

t≦

t₄

where;

C_F0 is the initial value of the torque, at time t₀

C_F0=C_F(t₀);

dC_F is the gradient of the temporal variation ramp, calculated as

${\mathrm{dC}}_F=K_{\mathrm{Jerk}}·<br><br>{\mathrm{jerk}}^{*}<br><br>\left[\mathrm{Nm}/\sec \right]$ $\mathrm{in}<br><br><br><br>\mathrm{which}$ $K_{\mathrm{Jerk}}=\frac{J_P·<br><br>\mathrm{\tau <br><br>}}{R}$

where J_P is the total moment of inertia transferred to the primary shaft, τ

is the selected transmission ratio and R is the rolling radius of the wheels; and

C_FSteady is a value of intermediate steady torque, defined as

$C_{\mathrm{FSteady}}=K_{\mathrm{MSteady}}·<br><br>C_{\mathrm{Driver}}$ $\mathrm{in}<br><br><br><br>\mathrm{which}$ $K_{\mathrm{MSteady}}=\frac{J_P}{J_M+J_P}$

where J_M is the total moment of inertia of the engine and C_Driver is the reference steady torque for the clutch at the end of the driving-away manoeuvre;

and

the reference torque request signal indicating the reference torque requested from the drive shaft has the following temporal variation;

C_MRif(t)=C_M0+dC_M·

t for t₀≦

t≦

t₁

C_MRif(t)=C_Msteady for t₁<

t≦

t₃

C_MRif(t)=C_Msteady+dC_MC1·

t for t₃<

t≦

t₄

where;

C_M0 is the initial value of the torque, at time t₀

C_M0=C_M(t₀);

dC_M is the gradient of the temporal variation ramp, calculated as

${\mathrm{dC}}_M=\frac{1}{\left(\frac{1}{{\mathrm{dC}}_F}-\frac{2·<br><br>\left({\mathrm{\omega <br><br>}}_{\mathrm{Msp}}-{\mathrm{\omega <br><br>}}_{M<br><br><br><br>0}\right)·<br><br>J_M}{{\left(C_{\mathrm{MSteady}}-C_{M<br><br><br><br>0}\right)}^2}\right)}$

in which ω

_M0 is the initial value of the rotation speed of the engine, at time t₀

ω

_M0=ω

_M(t₀), and

C_MSteady is a value of intermediate steady torque, defined as

$C_{\mathrm{MSteady}}=K_{\mathrm{MSteady}}·<br><br>C_{\mathrm{Driver}}$ $\mathrm{where}$ $K_{\mathrm{MSteady}}=\frac{J_P}{J_M+J_P}$

and C_Driver is the reference steady torque for the engine at the end of the driving-away manoeuvre; and

dC_MCI is the gradient of the temporal variation ramp in a terminal stage for inertia compensation, defined as;

${\mathrm{dC}}_{\mathrm{MC}<br><br><br><br>1}=\frac{C_{\mathrm{Driver}}-C_{\mathrm{MSteady}}}{2·<br><br>\left(J_M+J_P\right)·<br><br>\mathrm{\Delta <br><br>}<br><br><br><br>{\mathrm{\omega <br><br>}}_{C<br><br><br><br>1}}·<br><br>C_{\mathrm{Driver}}$

in which Δ

ω

_CI is a threshold value of difference between the angular velocities of the drive shaft and of the gearbox primary input shaft calculated by the estimator module,

the said inertia compensation stage being adapted to ensure the synchronization of the angular velocities of the drive shaft and of the primary input shaft in such a way as to avoid discontinuities in the acceleration of the vehicle due to the variations of the equivalent moment of inertia of the system following the engagement of the friction clutch.