Motor torque control apparatus and method for automotive vehicle

• US 20060017414A1
• Filed: 07/14/2005
• Published: 01/26/2006
• Est. Priority Date: 07/21/2004
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Joe, Shinichiro, Kawabe, Taketoshi
• Granted Patent: US 7,164,247 B2
• Time in Patent Office: Days
• US Class Current: 318/432
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/105 Output torque
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: F16H 2037/103 Power split variators with each end of the CVT connected or connectable to a Ravigneaux set
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

A motor torque control apparatus for an automotive vehicle includes a transmission which has either one of a fixed speed ratio and a variable speed ratio; at least one motor/generator coupled with the transmission as a propelling power source of the vehicle, a power of the power source being transmitted to a road wheel for propulsion of the vehicle through the transmission; and a controller configured to be electrically connected to the motor/generator for motor torque control. Moreover, this controller includes a disturbance observer that estimates a driving force, and a motor torque control section that controls the driving force estimated by the disturbance observer, to bring the estimated driving force closer to a target driving force by way of servo control.

Claims

1. A motor torque control apparatus for an automotive vehicle, comprising:

a transmission which has either one of a fixed speed ratio and a variable speed ratio;

at least one motor-and-generator coupled with the transmission as a propelling power source of the vehicle, a power of the power source being transmitted to a road wheel for propulsion of the vehicle through the transmission; and

a controller configured to be electrically connected to the motor-and-generator for motor torque control, the controller comprising

(a) a disturbance observer that estimates a driving force; and

(b) a motor torque control section that controls the driving force estimated by the disturbance observer, to bring the estimated driving force closer to a target driving force by way of servo control.

2. The motor torque control apparatus as claimed in claim 1, wherein the disturbance observer is configured to estimate the driving force of the vehicle from rotation speed of an output shaft of the transmission and a target motor torque for the motor-and-generator.

3. The motor torque control apparatus as claimed in claim 1, wherein the controller comprises:

an output-shaft rotation speed sensing section configured to sense rotation speed of an output shaft of the transmission;

a disturbance estimating section configured to estimate a reaction torque from a wheel shaft to the transmission as a disturbance, by receiving the output shaft'"'"'s rotation speed and a target motor torque;

a driving force control section configured to regard the estimated disturbance as the estimated driving force, and configured to calculate a driving force control torque to bring the estimated driving force closer to the target driving force set according to request by a driver or some system; and

a target motor torque calculating section configured to calculate the target motor torque for the motor-and-generator, in accordance with the driving force control torque.

4. The motor torque control apparatus as claimed in claim 3, wherein

the controller further comprises a disturbance cancellation quantity calculating section configured to regard the reversely signed value of the estimated disturbance, as a disturbance cancellation torque suppressing a resonance of the wheel shaft;

and

the target motor torque calculating section is configured to calculate the target motor torque in accordance with the sum of the disturbance cancellation torque and the driving force control torque.

5. The motor torque control apparatus as claimed in claim 1, wherein

the automotive vehicle is an electric or hybrid vehicle which has at least two motor-and-generators as power sources and which runs by transmitting the power to the wheel through the transmission including a differential gear having two-degrees-of-freedom in that when any two rotation speeds among power sources and output members of the differential gear are determined, all the remaining rotation speeds are accordingly determined, and wherein

the controller is configured to control motor torque in such a manner that

a driving force control torque calculated so as to bring the estimated driving force closer to the target driving force is only used for variation in rotational acceleration of an output shaft, and

a shift control torque calculated so as to reduce the difference between an actual speed ratio and a target speed ratio is only used for a shift controlled variable.

6. The motor torque control apparatus as claimed in claim 5, wherein the controller comprises:

a rotation speed sensing section configured to sense rotation speed of the output shaft and one of rotation speeds of the power sources;

a shift control section configured to regard the sensed rotation speed of the power source as the shift controlled variable, and configured to calculate the shift control torque so as to reduce the difference between the target speed ratio and the speed ratio defined by a ratio between the shift controlled variable and the output shaft'"'"'s rotation speed;

a disturbance estimating section configured to estimate a reaction torque from a wheel shaft to the transmission as a disturbance, by receiving the output shaft'"'"'s rotation speed and a target motor torque;

a driving force control section configured to regard the estimated disturbance as the estimated driving force, and configured to calculate the driving force control torque to bring the estimated driving force closer to the target driving force set according to request by a driver or some system; and

a target motor torque calculating section configured to calculate the target motor torque for the motor-and-generator, in such a manner that the driving force control torque is only used for variation in rotational acceleration of the output shaft and the shift control torque is only used for the shift controlled variable.

7. The motor torque control apparatus as claimed in claim 6, wherein

the controller further comprises a disturbance cancellation quantity calculating section configured to regard the reversely signed value of the estimated disturbance, as a disturbance cancellation torque suppressing a resonance of the wheel shaft;

and

the target motor torque calculating section is configured to calculate the target motor torque in such a manner that;

the sum of the disturbance cancellation torque and the driving force control torque is only used for variation in rotational acceleration of the output shaft; and

the shift control torque is only used for the shift controlled variable.

8. The motor torque control apparatus as claimed in claim 1, wherein

the motor torque control apparatus comprises an engine, a first motor-and-generator, and a second motor-and-generator as power sources, and

the transmission is a hybrid transmission for the hybrid vehicle, the hybrid transmission including:

a differential gear coupled with the engine, an output member toward a drive system of the vehicle, the first motor-and-generator, and the second motor-and-generator in such a way that

two rotation members of the engine and the output member are respectively arrayed inwardly on an alignment chart of the differential gear, on which at least four rotation members can be arrayed, and

two rotation members of the first motor-and-generator and the second motor-and-generator are respectively arrayed outwardly on the alignment chart; and

an friction element configured to change the mode of the transmission between a variable speed ratio mode and a fixed speed ratio mode, by an engagement/disengagement control of the friction element.

9. The motor torque control apparatus as claimed in claim 1, wherein the disturbance observer estimates a running resistance torque and a torsional torque of a drive shaft.

10. The motor torque control apparatus as claimed in claim 9, wherein the controller comprises:

an output-shaft rotation speed sensing section configured to sense rotation speed of an output shaft of the transmission;

a wheel rotation speed sensing section configured to sense rotation speed of a wheel coupled with the transmission;

a disturbance estimating section configured to estimate the running resistance torque and the reaction torque from the drive shaft to the transmission, as a disturbance, by receiving the output shaft'"'"'s rotation speed, the wheel'"'"'s rotation speed and a target motor torque;

a disturbance cancellation quantity calculating section configured to regard the reversely signed value of the estimated reaction torque, as a disturbance cancellation torque suppressing a resonance of the drive shaft;

a target acceleration calculating section configured to calculate a target acceleration of the vehicle, from the target driving force set according to request by a driver or some system, and from the estimated running resistance torque derived from the disturbance estimating section; and

a target motor torque calculating section configured to calculate the target motor torque for the motor-and-generator, in accordance with the sum of the disturbance cancellation torque derived from the disturbance cancellation quantity calculating section and the target acceleration derived from the target acceleration calculating section.

11. The motor torque control apparatus as claimed in claim 9, wherein

the automotive vehicle is an electric or hybrid vehicle which has at least two motor-and-generators as power sources and which runs by transmitting the power to the wheel through the transmission including a differential gear having two-degrees-of-freedom in that when any two rotation speeds among power sources and output members of the differential gear are determined, all the remaining rotation speeds are accordingly determined, and wherein

the controller is configured to control motor torque in such a manner that

the sum of a disturbance cancellation torque calculated from the reversely signed value of the drive shaft'"'"'s torsional torque estimated by the disturbance observer, and a vehicle'"'"'s target acceleration calculated from the running resistance torque estimated by the disturbance observer, is only used for variation in rotational acceleration of an output shaft, and

a shift control torque calculated so as to reduce the difference between an actual speed ratio and a target speed ratio is only used for a shift controlled variable.

12. The motor torque control apparatus as claimed in claim 11, wherein the controller comprises:

a rotation speed sensing section configured to sense rotation speed of the output shaft and one of rotation speeds of the power sources;

a wheel rotation speed sensing section configured to sense rotation speed of the wheel coupled with the transmission;

a shift control section configured to regard the sensed rotation speed of the power source as the shift controlled variable, and configured to calculate the shift control torque so as to reduce the difference between the speed ratio defined by a ratio between the shift controlled variable and the output shaft'"'"'s rotation speed, and the target speed ratio;

a disturbance estimating section configured to estimate the running resistance torque and the reaction torque from the drive shaft to the transmission, as a disturbance, by receiving the output shaft'"'"'s rotation speed, the wheel'"'"'s rotation speed and a target motor torque;

a disturbance cancellation quantity calculating section configured to regard the reversely signed value of the estimated reaction torque, as a disturbance cancellation torque suppressing a resonance of the drive shaft;

a target acceleration calculating section configured to calculate the target acceleration of the vehicle, from the target driving force set according to request by a driver or some system, and from the estimated running resistance torque derived from the disturbance estimating section; and

a target motor torque calculating section configured to calculate the target motor torque for the motor-and-generator, in such a manner that the sum of the disturbance cancellation torque and the vehicle'"'"'s target acceleration is only used for variation in rotational acceleration of the output shaft, and that the shift control torque is only used for the shift controlled variable.

13. The motor torque control apparatus as claimed in claim 9, wherein

the motor torque control apparatus comprises an engine, a first motor-and-generator, and a second motor-and-generator as power sources,

the transmission is a hybrid transmission for a hybrid vehicle, the hybrid transmission including:

a differential gear coupled with the engine, an output member toward a drive system of the vehicle, the first motor-and-generator, and the second motor-and-generator in such a way that

two rotation members of the engine and the output member are respectively arrayed inwardly on an alignment chart of the differential gear, on which at least four rotation members can be arrayed, and

two rotation members of the first motor-and-generator and the second motor-and-generator are respectively arrayed outwardly on the alignment chart; and

an friction element configured to change the mode of the transmission between a variable speed ratio mode and a fixed speed ratio mode, by an engagement/disengagement control of the friction element.

14. The motor torque control apparatus as claimed in claim 1, wherein

the motor torque control apparatus further comprises an friction element configured to change the mode of the transmission between two different modes of a first mode and a second mode by an engagement/disengagement of the friction element, and wherein

the controller is configured to

estimate the driving force by the disturbance observer and calculate a target motor torque by a feedback driving force control to bring the estimated driving force closer to the target driving force, under the condition of the first mode or the second mode, and is configured to

calculate the target motor torque which achieves a target vehicle'"'"'s acceleration according to acceleration at start time of the mode change between the first mode and the second mode, by a feedforward acceleration control, during transition of the mode change.

15. The motor torque control apparatus as claimed in claim 14, wherein the controller comprises:

an output-shaft rotation speed sensing section configured to sense rotation speed of an output shaft of the transmission;

a disturbance estimating section configured to estimate a reaction torque from a drive shaft to the transmission as a disturbance, by receiving the output shaft'"'"'s rotation speed and the target motor torque;

a driving force control section configured to regard the estimated disturbance as the estimated driving force, and configured to calculate a driving force control torque to bring the estimated driving force closer to the target driving force set according to request by a driver or some system;

a first-target motor torque calculating section configured to calculate a first target motor torque for the motor-and-generator, in accordance with the driving force control torque;

a target acceleration calculating section configured to calculate the target acceleration on the basis of acceleration at start time of the mode change;

a second-target motor torque calculating section configured to calculate a second target motor torque for the motor-and-generator, in accordance with the target acceleration; and

a control switching section configured to select the first target motor torque derived from the first-target motor torque calculating section under the condition of the first mode or the second mode, and select the second target motor torque derived from the second-target motor torque calculating section during transition of the mode change between the first mode and the second mode.

16. The motor torque control apparatus as claimed in claim 15, wherein the target acceleration calculating section is configured to set the present target vehicle'"'"'s acceleration and one of an present accelerator opening and the present target driving force, at start time of the mode change caused by engagement/disengagement of the friction element, as default values, and configured to increase/decrease the default value of the target vehicle'"'"'s acceleration in accordance with increase/decrease of the default value of the accelerator opening or the target driving force during engagement or disengagement state of the friction element.

17. The motor torque control apparatus as claimed in claim 15, wherein

the controller further comprises a disturbance cancellation quantity calculating section configured to regard the reversely signed value of the estimated disturbance, as a disturbance cancellation torque suppressing a resonance of the drive shaft;

and

the first-target motor torque calculating section is configured to calculate the first target motor torque in accordance with the sum of the disturbance cancellation torque and the driving force control torque.

18. The motor torque control apparatus as claimed in claim 15, wherein:

at least one of the first mode and the second mode is the mode having two-degrees-of-rotational-freedom in which when any two rotation speeds among power sources and output members of the transmission are determined, all the remaining rotation speeds are accordingly determined;

the controller further comprises a shift control section configured to regard any one rotation speed of the power sources as a shift controlled variable, and configured to calculate a shift control torque so as to reduce the difference between a speed ratio defined by the ratio between the shift controlled variable and the output shaft'"'"'s rotation speed, and a target speed ratio; and

the first-target motor torque calculating section configured to calculate the first target motor torque, in the case of the mode having two-degrees-of-rotational-freedom, in such a manner that

the driving force control torque calculated so as to bring the estimated driving force closer to the target driving force is only used for variation in rotational acceleration of the output shaft, and

the shift control torque calculated so as to reduce the difference between the actual speed ratio and the target speed ratio is only used for the shift controlled variable.

19. The motor torque control apparatus as claimed in claim 14, wherein

the motor torque control apparatus comprises an engine, a first motor-and-generator, and a second motor-and-generator as power sources,

the transmission is a hybrid transmission for a hybrid vehicle, the hybrid transmission including:

a differential gear coupled with the engine, an output member toward a drive system of the vehicle, the first motor-and-generator, and the second motor-and-generator in such a way that

two rotation members of the engine and the output member are respectively arrayed inwardly on an alignment chart of the differential gear, on which at least four rotation members can be arrayed, and

two rotation members of the first motor-and-generator and the second motor-and-generator are respectively arrayed outwardly on the alignment chart;

an engine clutch configured to change the mode of the vehicle between a hybrid vehicle mode and an electric vehicle mode, by an engagement/disengagement control of the engine clutch; and

a low brake configured to change the mode of the transmission between a variable speed ratio mode and a fixed speed ratio mode, by an engagement/disengagement control of the low brake.

20. A motor torque control apparatus for an automotive vehicle, comprising:

a transmission which has either one of a fixed speed ratio and a variable speed ratio;

at least one motor-and-generator coupled with the transmission as a propelling power source of the vehicle, a power of the power source being transmitted to a road wheel for propulsion of the vehicle through the transmission; and

a controller configured to be electrically connected to the motor-and-generator for motor torque control, the controller comprising

(a) observer means for estimating a driving force of the vehicle; and

(b) control means for controlling the driving force estimated by the observer means, to bring the estimated driving force closer to a target driving force by way of servo control.

21. A motor torque control method for an automotive vehicle, the vehicle being an electric or hybrid vehicle which has at least one motor-and-generator as a propelling power source and which runs by transmitting a power of the power source to a road wheel through a transmission, the motor torque control method comprising:

estimating a driving force of the vehicle by a disturbance observer; and

controlling the motor-and-generator to bring the estimated driving force closer to a target driving force by way of servo control.