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A vehicle brake system includes a brake actuator associated with a tire, the brake actuator having at least one moveable brake component, and a brake control system. The brake control system is operative to determine a target position of the at least one moveable brake component based at least in pa

A vehicle brake system includes a brake actuator associated with a tire, the brake actuator having at least one moveable brake component, and a brake control system. The brake control system is operative to determine a target position of the at least one moveable brake component based at least in part upon a relationship between an actual tire/road friction force and a target tire/road friction force, and to control actuation of the brake actuator based at least in part upon the target position of the at least one moveable brake component and at least in part based upon a current position of the at least one moveable brake component. The target tire/road friction force may be determined based at least in part upon a relationship between vertical force acting on the tire, optimal tire slip, slip angle, at least one road dependant parameter, and at least one tire dependant parameter.

대표청구항 ▼

What is claimed is: 1. A vehicle brake system comprising: a brake actuator associated with a tire, said brake actuator having at least one moveable brake component; a brake control system operative to determine a target position of the at least one moveable brake component based at least in part up

What is claimed is: 1. A vehicle brake system comprising: a brake actuator associated with a tire, said brake actuator having at least one moveable brake component; a brake control system operative to determine a target position of the at least one moveable brake component based at least in part upon a relationship between an actual tire/road friction force and a target tire/road friction force; and wherein said brake control system is operable to control actuation of said brake actuator based at least in part upon the target position of the at least one moveable brake component and at least in part based upon a current position of the at least one moveable brake component. 2. The vehicle brake system of claim 1 wherein the target tire/road friction force is determined based at least in part upon a relationship between vertical force acting on the tire, optimal tire slip, slip angle, at least one road dependant parameter, and at least one tire dependant parameter. 3. The vehicle brake system of claim 2 wherein the target tire/road friction force (F��road) is determined employing the following relationship: description="In-line Formulae" end="lead"F��road=[fx2(F load, slip��, α, Road, Tire)+fy2(Fload, slip��, α, Road, Tire)]1/2description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, slip�� represents optimal tire slip, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 4. The vehicle brake system of claim 2 wherein tire slip (slip) and slip angle (α) are defined as: description="In-line Formulae" end="lead"slip=(νx-Reωwheel) /νx; tan(α)=νy/νxdescription="In-line Formulae" end="tail" wherein νx represents linear velocity in a longitudinal direction, νy represents linear velocity in a lateral direction, Re is the rolling radius, defined as νx/ωwheel for a free rolling tire that does not transmit substantially any tire forces, and ωwheel represents a wheel rotational velocity. 5. The vehicle brake system of claim 2 wherein optimal tire slip (slip��) is defined as: description="In-line Formulae" end="lead"slipo=gx(Fload, α, Road, Tire)description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 6. The vehicle brake system of claim 2 wherein the at least one tire dependant parameter comprises tire stiffness in a longitudinal direction and in a lateral direction. 7. The vehicle brake system of claim 2 wherein the at least one road dependant parameter comprises a tire/road friction coefficient. 8. The vehicle brake system of claim 1 wherein the brake control system is operative to determine a target rotational velocity of the tire based at least in part on the difference between the actual tire/road friction force and the target tire/road friction force, and then to determine the target position of the at least one moveable brake component based at least in part upon the target rotational velocity of the tire. 9. The vehicle brake system of claim 1 wherein the actual tire/road friction force is determined based at least in part upon determined static and dynamic properties of tire/road interactions of the wheel, at least in part upon a determined tire/road wheel slip of the wheel, at least in part upon a determined load force of the wheel, and at least in part upon a determined tire/road friction coefficient of the wheel. 10. The vehicle brake system of claim 1 wherein the actual tire/road friction force is determined based at least in part upon a determined brake torque and at least in part upon a determined rotational acceleration/retardation of the wheel. 11. The vehicle brake system of claim 10 wherein the actual tire/road friction force is determined based further at least in part upon dimensions of the wheel. 12. The vehicle brake system of claim 1 wherein said brake actuator comprises a self-energizing brake actuator. 13. The vehicle brake system of claim 12 wherein said brake actuator comprises an electromechanical brake actuator, actuation of which is at least partially achieved employing an electric motor. 14. A vehicle brake system comprising: a brake actuator associated with a tire, said brake actuator having at least one moveable brake component; a brake control system operative to determine a target rotational velocity of the wheel based at least in part on a relationship between an actual tire/road friction force and a target tire/road friction force, said brake control system determining a target position of the at least one moveable brake component based at least in part upon the target rotational velocity; wherein the target tire/road friction force is determined based at least in part upon a relationship between vertical force acting on the tire, optimal tire slip, slip angle, at least one road dependant parameter, and at least one tire dependant parameter; and wherein said brake control system is operable to control actuation of said brake actuator based at least in part upon the target position of the at least one moveable brake component and at least in part based upon a current position of the at least one moveable brake component. 15. The vehicle brake system of claim 14 wherein the target tire/road friction force (F��road) is determined employing the following relationship: description="In-line Formulae" end="lead"F��road=[fx2(F load, slip��, α, Road, Tire)+fy2(Fload, slip��, α, Road, Tire)]1/2description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, slip�� represents optimal tire slip, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 16. The vehicle brake system of claim 14 wherein tire slip (slip) and slip angle (α) are defined as: description="In-line Formulae" end="lead"slip=(νx-Reωwheel) /νx; tan(α)=νy/νxdescription="In-line Formulae" end="tail" wherein νx represents linear velocity in a longitudinal direction, νy represents linear velocity in a lateral direction, Re is the rolling radius, defined as νx/ωwheel for a free rolling tire that does not transmit substantially any tire forces, and ωwheel represents a wheel rotational velocity. 17. The vehicle brake system of claim 14 wherein optimal tire slip (slip��) is defined as: description="In-line Formulae" end="lead"slipo=gx(Fload, α, Road, Tire)description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 18. The vehicle brake system of claim 14 wherein the at least one tire dependant parameter comprises tire stiffness in a longitudinal direction and in a lateral direction. 19. The vehicle brake system of claim 14 wherein the at least one road dependant parameter comprises a tire/road friction coefficient. 20. The vehicle brake system of claim 14 wherein the actual tire/road friction force is determined based at least in part upon determined static and dynamic properties of tire/road interactions of the wheel, at least in part upon a determined tire/road wheel slip of the wheel, at least in part upon a determined load force of the wheel, and at least in part upon a determined tire/road friction coefficient of the wheel. 21. The vehicle brake system of claim 14 wherein the actual tire/road friction force is determined based at least in part upon a determined brake torque and at least in part upon a determined rotational acceleration/retardation of the wheel. 22. The vehicle brake system of claim 21 wherein the actual tire/road friction force is determined based further at least in part upon dimensions of the wheel. 23. The vehicle brake system of claim 14 wherein said brake actuator comprises a self-energizing brake actuator. 24. The vehicle brake system of claim 23 wherein said brake actuator comprises an electromechanical brake actuator, actuation of which is at least partially achieved employing an electric motor. 25. A method for controlling a brake actuator associated with a tire, the brake actuator having at least one moveable brake component, the method comprising the steps of: determining a target position of the at least one moveable brake component based at least in part upon a relationship between an actual tire/road friction force and a target tire/road friction force; and controlling actuation of the brake actuator based at least in part upon the target position of the at least one moveable brake component and at least in part based upon a current position of the at least one moveable brake component. 26. The method of claim 25 further comprising the step of determining the target tire/road friction force based at least in part upon a relationship between vertical force acting on the tire, optimal tire slip, slip angle, at least one road dependant parameter, and at least one tire dependant parameter. 27. The method of claim 26 wherein the target tire/road friction force (F��road) is determined employing the following relationship: description="In-line Formulae" end="lead"F��road=[fx2(F load, slip��, α, Road, Tire)+fy2(Fload, slip��, α, Road, Tire)]1/2description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, slip�� represents optimal tire slip, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 28. The method of claim 26 wherein tire slip (slip) and slip angle (α) are defined as: description="In-line Formulae" end="lead"slip=(νx-Reωwheel) /νx; tan(α)=νy/νxdescription="In-line Formulae" end="tail" wherein νx represents linear velocity in a longitudinal direction, νy represents linear velocity in a lateral direction, Re is the rolling radius, defined as νx/ωwheel for a free rolling tire that does not transmit substantially any tire forces, and ωwheel represents a wheel rotational velocity. 29. The method of claim 26 wherein optimal tire slip (slip��) is defined as: description="In-line Formulae" end="lead"slipo=gx(Fload, α, Road, Tire)description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 30. The method of claim 26 wherein the at least one tire dependant parameter comprises tire stiffness in a longitudinal direction and in a lateral direction. 31. The method of claim 26 wherein the at least one road dependant parameter comprises a tire/road friction coefficient. 32. The method of claim 25 further comprising the steps of determining a target rotational velocity of the tire based at least in part on the difference between the actual tire/road friction force and the target tire/road friction force, and then determining the target position of the at least one moveable brake component based at least in part upon the target rotational velocity of the tire. 33. The method of claim 25 further comprising the step of determining the actual tire/road friction force based at least in part upon determined static and dynamic properties of tire/road interactions of the wheel, at least in part upon a determined tire/road wheel slip of the wheel, at least in part upon a determined load force of the wheel, and at least in part upon a determined tire/road friction coefficient of the wheel. 34. The method of claim 25 further comprising the step of determining the actual tire/road friction force based at least in part upon a determined brake torque and at least in part upon a determined rotational acceleration/retardation of the wheel. 35. The method of claim 34 wherein the actual tire/road friction force is determined based further at least in part upon dimensions of the wheel. 36. The method of claim 25 wherein the brake actuator comprises a self-energizing brake actuator. 37. The method of claim 36 wherein the brake actuator comprises an electromechanical brake actuator, actuation of which is at least partially achieved employing an electric motor. 38. A method for controlling a brake actuator associated with a tire, the brake actuator having at least one moveable brake component, the method comprising the steps of: determining a target tire/road friction force based at least in part upon a relationship between vertical force acting on the tire, optimal tire slip, slip angle, at least one road dependant parameter, and at least one tire dependant parameter; determining a target rotational velocity of the wheel based at least in part on a relationship between an actual tire/road friction force and the target tire/road friction force; determining a target position of the at least one moveable brake component based at least in part upon the target rotational velocity; and controlling actuation of the brake actuator based at least in part upon the target position of the at least one moveable brake component and at least in part based upon a current position of the at least one moveable brake component. 39. The method of claim 38 wherein the target tire/road friction force (F��road) is determined employing the following relationship: description="In-line Formulae" end="lead"F��road=[fx2(F load, slip��, α, Road, Tire)+fy2(Fload, slip��, α, Road, Tire)]1/2description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, slip�� represents optimal tire slip, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 40. The method of claim 38 wherein tire slip (slip) and slip angle (α) are defined as: description="In-line Formulae" end="lead"slip=(νx-Reωwheel) /νx; tan(α)=νy/νxdescription="In-line Formulae" end="tail" wherein νx represents linear velocity in a longitudinal direction, νy represents linear velocity in a lateral direction, Re is the rolling radius, defined as νx/ωwheel for a free rolling tire that does not transmit substantially any tire forces, and ωwheel represents a wheel rotational velocity. 41. The method of claim 38 wherein optimal tire slip (slip��) is defined as: description="In-line Formulae" end="lead"slipo=gx(Fload, α, Road, Tire)description="In-line Formulae" end="tail" wherein Fload represents vertical force acting on the tire, α represents slip angle, Road represents at least one road dependant parameter, and Tire represents at least one tire dependant parameter. 42. The method of claim 38 wherein the at least one tire dependant parameter comprises tire stiffness in a longitudinal direction and in a lateral direction. 43. The method of claim 38 wherein the at least one road dependant parameter comprises a tire/road friction coefficient. 44. The method of claim 38 further comprising the step of determining the actual tire/road friction force based at least in part upon determined static and dynamic properties of tire/road interactions of the wheel, at least in part upon a determined tire/road wheel slip of the wheel, at least in part upon a determined load force of the wheel, and at least in part upon a determined tire/road friction coefficient of the wheel. 45. The method of claim 38 further comprising the step of determining the actual tire/road friction force based at least in part upon a determined brake torque and at least in part upon a determined rotational acceleration/retardation of the wheel. 46. The method of claim 45 wherein the actual tire/road friction force is determined based further at least in part upon dimensions of the wheel. 47. The method of claim 38 wherein the brake actuator comprises a self-energizing brake actuator. 48. The method of claim 47 wherein the brake actuator comprises an electromechanical brake actuator, actuation of which is at least partially achieved employing an electric motor.