Electric power assisted steering systems
First Claim
1. A vehicle comprising an electric power assist steering (EPAS) system having a controller unit, a steering wheel, an electric motor, and a rack coupled to and disposed between both the steering wheel and the electric motor, wherein the controller unit of the EPAS system is configured to receive a detected value of steering wheel angle and/or steering wheel angular velocity at a position between the steering wheel and the rack, and wherein the controller unit of the EPAS system is configured to improve the accuracy of the detected value of steering wheel angle and/or steering wheel angular velocity by compensating for an angular phasing of the joint between any two linked components of the steering mechanism by carrying out a computation to derive an improved value of steering wheel angle and/or steering wheel angular velocity from the detected value of steering wheel angle and/or steering wheel angular velocity, which computation accounts for an angle at a joint (δ
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5) between the two linked components that is located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or the steering wheel angular velocity value, and wherein said compensation is carried out using any one or more of the following relationships;
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Accused Products
Abstract
A vehicle comprising an electric power assist steering (EPAS) system, wherein the EPAS system is configured to receive a detected value of steering wheel angle and/or steering wheel angular velocity and wherein the EPAS system is configured to improve the accuracy of the detected value of steering wheel angle and/or steering wheel angular velocity by compensating for any one or more of an angular phasing of the joint between any two linked components of the steering mechanism and the effect on steering wheel angle of the deflection across a torque sensor at least substantially due to the stiffness of that torque sensor.
17 Citations
12 Claims
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1. A vehicle comprising an electric power assist steering (EPAS) system having a controller unit, a steering wheel, an electric motor, and a rack coupled to and disposed between both the steering wheel and the electric motor, wherein the controller unit of the EPAS system is configured to receive a detected value of steering wheel angle and/or steering wheel angular velocity at a position between the steering wheel and the rack, and wherein the controller unit of the EPAS system is configured to improve the accuracy of the detected value of steering wheel angle and/or steering wheel angular velocity by compensating for an angular phasing of the joint between any two linked components of the steering mechanism by carrying out a computation to derive an improved value of steering wheel angle and/or steering wheel angular velocity from the detected value of steering wheel angle and/or steering wheel angular velocity, which computation accounts for an angle at a joint (δ
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5) between the two linked components that is located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or the steering wheel angular velocity value, and wherein said compensation is carried out using any one or more of the following relationships;
- View Dependent Claims (2, 3, 4, 5, 6, 7)
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5) between the two linked components that is located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or the steering wheel angular velocity value, and wherein said compensation is carried out using any one or more of the following relationships;
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8. A vehicle comprising an electric power assist steering (EPAS) system having a controller unit, a steering wheel, an electric motor, and a rack coupled to and disposed between both the steering wheel and the electric motor, wherein the controller unit of the EPAS system is configured to receive a detected value of steering wheel angle and/or steering wheel angular velocity at a position between the steering wheel and the rack, and wherein the controller unit of the EPAS system is configured to improve the accuracy of the detected value of steering wheel angle and/or steering wheel angular velocity by compensating for an angular phasing of the joint between any two linked components of the steering mechanism and/or drive mechanism by carrying out a computation to derive an improved value of steering wheel angle and/or steering wheel angular velocity from the detected value of steering wheel angle and/or steering wheel angular velocity, which computation accounts for an angle at a joint (δ
- 5) between the two linked components that is located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or the steering wheel angular velocity value, and wherein the EPAS system is configured to use at least an approximation of a torque contribution (Tweight) to the steering wheel torque caused by the presence of one or more weights disposed in the steering wheel in an off-centre position to compensate for that torque contribution (Tweight) by computing a corrected value of steering wheel torque from a detected value of steering wheel torque and/or to compensate for that torque contribution (Tweight) by computing a corrected value of assistive motor torque.
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9. An electric power assist steering (EPAS) system for a vehicle having a controller unit, a steering wheel, an electric motor, and a rack coupled to and disposed between both the steering wheel and electric motor, wherein the controller unit of the system is configured to receive a detected value of steering wheel angle and/or steering wheel angular velocity at a position between the steering wheel and the rack, and to improve the accuracy of the detected value of steering wheel angle and/or steering wheel angular velocity by compensating for an angular phasing of the joint between any two linked components of the steering mechanism by carrying out a computation which accounts for an angle at a joint (δ
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5) between the two linked components that is located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or steering wheel angular velocity value, wherein said compensation is carried out using any one or more of the following relationships;
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5) between the two linked components that is located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or steering wheel angular velocity value, wherein said compensation is carried out using any one or more of the following relationships;
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10. A method of assisting the steering of a vehicle, the method comprising:
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(a) providing an electric power assist steering (EPAS) system having a steering wheel and an electric motor both coupled to a rack wherein the rack is disposed between the steering wheel and the electric motor, and a controller configured to adjust a detected variable value used by the controller of the EPAS system; (b) receiving a detected value of steering wheel angle or steering wheel angular velocity at a position between the steering wheel and the rack of the EPAS system; (c) adjusting the detected value of steering wheel angle or steering wheel angular velocity by compensating for a phasing of a joint between any two linked components of a steering mechanism located between the steering wheel and the position corresponding to the detected steering wheel angle value or the steering wheel angular velocity value, said compensation being carried out using any one or more of the following relationships;
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11. A controller for use in an EPAS system of a vehicle having a steering wheel and an electric motor both coupled to a rack wherein the rack is disposed between the steering wheel and the electric motor, the controller including a program containing one or more algorithms such that when running, the program is configured to compensate for an inaccuracy in a detected steering wheel angle and/or detected steering wheel angular velocity, the program configured to receive a detected value of steering wheel angle and/or steering wheel angular velocity at a position between the steering wheel and the rack and configured to adjust the detected value to compensate for an angular phasing of a joint between any two linked components of the steering mechanism by carrying out a computation which accounts for an angle at a joint (δ
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5) between the two components and located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or the steering wheel angular velocity value, wherein said compensation is carried out using any one or more of the following relationships;
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5) between the two components and located between the steering wheel and the position corresponding to the detected steering wheel angle value and/or the steering wheel angular velocity value, wherein said compensation is carried out using any one or more of the following relationships;
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12. A vehicle comprising an electric power assist steering (EPAS) system, wherein the EPAS system is configured to receive a detected value of steering wheel angle (α
- ) and/or steering wheel angular velocity and wherein the EPAS system is configured to improve the accuracy of the detected value of steering wheel angle and/or steering wheel angular velocity by compensating for an angular phasing of a joint between any two linked components of the steering mechanism by carrying out a computation to derive an improved value of steering wheel angle and/or steering wheel angular velocity from the detected value of steering wheel angle (α
) and/or steering wheel angular velocity, which computation accounts for an angle at a joint (δ
5) between the two linked components, wherein said compensation is carried out using any one or more of the following relationships;
- ) and/or steering wheel angular velocity and wherein the EPAS system is configured to improve the accuracy of the detected value of steering wheel angle and/or steering wheel angular velocity by compensating for an angular phasing of a joint between any two linked components of the steering mechanism by carrying out a computation to derive an improved value of steering wheel angle and/or steering wheel angular velocity from the detected value of steering wheel angle (α
Specification