SYSTEM FOR CONTROLLING A VEHICLE WITH DETERMINATION OF THE SPEED THEREOF RELATIVE TO THE GROUND

• US 20100256887A1
• Filed: 11/10/2008
• Published: 10/07/2010
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: Compagnie Generale DES Etablissements Michelin SCA
• Original Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA), Societe De Technologie Michelin (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Linda, Jean-Louis, Walser, Daniel
• Granted Patent: US 8,527,177 B2
• Time in Patent Office: Days
• US Class Current: 701/82
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2240/16 longitudinal
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/465 Slip
• CPC Class Codes: B60L 3/10 Indicating wheel slip ; Correction of wheel slip
• CPC Class Codes: B60T 2250/04 Vehicle reference speed; Vehicle body speed
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2710/18 Braking system
• CPC Class Codes: B60W 2720/28 Wheel speed
• CPC Class Codes: B60W 40/06 Road conditions
• CPC Class Codes: B60W 40/072 Curvature of the road
• CPC Class Codes: B60W 40/076 Slope angle of the road
• CPC Class Codes: B60W 40/101 Side slip angle of tyre
• CPC Class Codes: B60W 40/105 Speed
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A system for controlling the behaviour of a vehicle relative to the ground is described wherein the linear ground speed of a vehicle that has at least two wheels (1) each equipped with a sensor suitable for supplying a measurement that is a function of the rotation of said wheel is determined at each instant. The system comprises a circumferential speed indicator (101, 102) for each wheel (1) based on the measurement from the corresponding sensor (11) and a system for diagnosing characteristic parameters of the instantaneous condition of said wheels to validate the use of the circumferential speed V_r measured for each of these wheels to produce an estimation of the instantaneous speed Vv of the vehicle relative to the ground. The diagnostic system notably comprises a means (109) of diagnosing loss of road grip of a wheel as a function of its instantaneous acceleration, a means (107) of diagnosing the validity of the wheel speed indication based on a measurement of the road grip coefficient of the wheel and a means (113) of diagnosing the maintaining or restoration of road grip of the wheel as a function of a determination of its slip. A vehicle speed indicator (119) produces an estimation of the vehicle speed relative to the ground as a function of indications that are not rejected on completion of the diagnoses carried out. The invention also targets the application of this speed estimation system to the determination of the instantaneous slip when rolling of the wheels of a vehicle, each coupled to an individual electric machine and to the control of the torque applied to each of these wheels as a function of this slip to improve the behaviour of the vehicle.

Claims

1-22. -22. (canceled)

23. Vehicle control system that provides an estimation of an instantaneous speed relative to a ground surface of a vehicle having at least two wheels, each wheel equipped with a sensor suitable for supplying a measurement that is a function of a rotation of the wheel at a given instant, the system comprising:

(a) an indicator suitable for supplying at an instant an indication that is a function of a circumferential wheel speed for each wheel from a measurement of a corresponding sensor of the wheel;

(b) a vehicle speed indicator suitable for producing a vehicle ground speed estimation at that instant as a function of indications obtained from the indicators upon completion of a step for diagnosing or testing a condition of the wheels; and

(c) a validation device that includes a first device for performing a road grip diagnosis or test indicating that a wheel is in a condition of road grip regardless of a state of the ground surface on which the wheel is rolling, based on at least one slip information data taken from another measurement on board the vehicle,

wherein the vehicle speed indicator operates based on information obtained from the validation device to produce an instantaneous vehicle speed estimation from an indication of a circumferential wheel speed of at least one wheel whose road grip has been ascertained by the first device.

24. Vehicle control system according to claim 23, wherein the slip information data is based on a previous estimation of vehicle speed and/or on a road grip coefficient measurement.

25. Vehicle control system according to claim 24, wherein the test of the first device is based on a slip criterion equal to or less than 3% and/or on a road grip coefficient criterion equal to or less than 15%.

26. Vehicle control system according to claim 23,

wherein the validation device includes a second device suitable for testing a loss of wheel road grip, and

wherein the first device operates on only those wheels that are subject to a positive test of no loss of road grip by the second device.

27. Vehicle control system according to claim 26, wherein the second device is suitable for detecting a loss of wheel road grip from a measurement of an acceleration of a wheel being tested, positive or negative, taken from a corresponding wheel sensor.

28. Vehicle control system according to claim 27, wherein the second device is suitable for detecting a loss of road grip of each wheel as a function of a threshold value that is different depending on whether the wheel is subject to an acceleration or a deceleration, to rule out an indication corresponding to a wheel with loss of road grip.

29. Vehicle control system according to claim 26, wherein the validation device further includes a third device for testing a validity of indications of circumferential wheel speed of a wheel to supply an acceptable approximation of vehicle speed, based on a measurement of a road grip coefficient of the wheel, wherein the vehicle speed indicator selectively operates to produce the instantaneous vehicle speed estimation from indications of circumferential wheel speed obtained from only those wheels whose condition corresponds to positive tests of at least two of the first, second, and third devices.

30. Vehicle control system according to claim 29, wherein the third device is suitable for testing a value of a road grip coefficient relative to a first threshold below which a circumferential wheel speed of a wheel under test can be retained as a valid approximation for computation of a ground speed of the vehicle at a position of that wheel.

31. Vehicle control system according to claim 30, wherein the diagnosis or test performed by the first device is based on (i) a test of a measurement of the road grip coefficient as a function of a second threshold lower than the first threshold and/or (ii) a test of a value of an instantaneous wheel slip rate, calculated from an estimation of vehicle speed at a preceding instant, relative to a predetermined threshold.

32. Vehicle control system according to claim 29, wherein the second device is suitable for detecting a loss of wheel road grip from a measurement of an acceleration of a wheel being tested, positive or negative, taken from a corresponding wheel sensor.

33. Vehicle control system according to claim 32, wherein the second device is suitable for detecting a loss of road grip of each wheel as a function of a threshold value that is different depending on whether a wheel is subject to an acceleration or a deceleration, to rule out an indication corresponding to a wheel with loss of road grip.

34. Vehicle control system according to claim 23, wherein the vehicle speed indicator is able to calculate an average value of speed indications retained by the validation device for an instant under consideration.

35. Vehicle control system according to claim 23, wherein the validation device includes a diagnosis device for diagnosing an integrity of an operation of the wheel sensors and/or of a data transmission network of the vehicle, the diagnosis device being coupled to an input of the validation device.

36. Vehicle control system according to claim 23, wherein the validation device includes a module for computing a road grip coefficient, the module operating in response to an indication of a torque applied to each wheel under consideration when running and to an indicator of a dynamic load of the vehicle on each wheel under consideration.

37. Vehicle control system according to claim 23, further comprising a sensor suitable for supplying to the validation device and the vehicle speed indicator an indication as a function of an instantaneous turn radius of the vehicle in a turn operation to produce an indication of the circumferential wheel speed of each wheel corrected as a function of the turn radius of the vehicle and of a position of that wheel in the turn operation.

38. Vehicle control system according to claim 26, wherein the first device is suitable for ascertaining a road grip condition of a wheel by testing if a value of wheel slip calculated based on a previous estimation of vehicle speed is equal or lower than a threshold of about 3%.

39. Vehicle control system according to claim 26, wherein the first device is suitable for indicating a road grip condition of a wheel by testing if a calculation of a road grip coefficient for that wheel is equal to or lower than about 15%.

40. Vehicle control system according to one of claim 23, 26, 29, or 31, wherein the vehicle control system is incorporated in a system for controlling the vehicle relative to the ground surface, based on a generation of an indication of an instantaneous slip of at least one wheel subject to a traction and/or braking torque when running,

wherein the system for controlling includes:

a sensor suitable for supplying a measurement that is a function of a rotation of a wheel,

a first indicator suitable for supplying a quantity as a function of the circumferential wheel speed based on the measurement of the sensor, and

a second indicator suitable for supplying an estimation of a speed of travel of the vehicle relative to the ground surface at a position of the wheel, based on the vehicle control system, and

a computation device that operates in response to the first and second indicators at a given instant to supply an indication of a slip of the wheel as a function of a difference between the circumferential wheel speed of the wheel and the speed of travel of the vehicle at the position of that wheel.

41. Vehicle control system according to one of claim 23, 26, 29, or 31, wherein the vehicle control system is incorporated in an electric traction vehicle equipped with at least one wheel coupled to a rotary electric machine suitable for fully and solely driving that wheel in traction and in braking.