Friction Plausibility Detection Algorithm For a Steering System
First Claim
1. A method for detecting and identifying friction in an electric power steering system for a vehicle, the method comprising the steps of:
- measuring predetermined vehicle states;
calculating idealized vehicle states using predetermined steering system signals and signals external to the steering system in predetermined state equations;
comparing the measured predetermined vehicle states to the idealized vehicle states to isolate signal data of interest and define an estimate of friction that is present in the steering system;
applying friction boundaries to the estimate of friction present in the steering system; and
setting an internal software flag for the purpose of acknowledging the presence of high friction in the event the estimate of friction exceeds the friction boundaries.
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Abstract
A system and method for detecting and identifying friction in a vehicle having an electric power steering system comprising the steps of measuring predetermined vehicle states, estimating vehicle states using predetermined signals to define idealized vehicle states, calculating a confidence factor to be applied to the idealized vehicle states to determine valid idealized vehicle states, comparing the measured predetermined vehicle states to the valid idealized vehicle states to isolate signal data of interest and define an estimate of friction present in the steering system, applying friction boundaries to the estimate of friction present in the steering system, qualifying the estimate of friction, and setting an internal software flag for the purpose of acknowledging the presence of high friction in the event the estimate of friction exceeds the friction threshold boundaries for a predetermined time.
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Citations
20 Claims
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1. A method for detecting and identifying friction in an electric power steering system for a vehicle, the method comprising the steps of:
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measuring predetermined vehicle states; calculating idealized vehicle states using predetermined steering system signals and signals external to the steering system in predetermined state equations; comparing the measured predetermined vehicle states to the idealized vehicle states to isolate signal data of interest and define an estimate of friction that is present in the steering system; applying friction boundaries to the estimate of friction present in the steering system; and setting an internal software flag for the purpose of acknowledging the presence of high friction in the event the estimate of friction exceeds the friction boundaries. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for detecting friction plausibility in a vehicle having an electric power steering system, the system comprising:
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a central communication control network providing signals representative of a plurality of vehicle states; an electric power steering system providing steering system signals; and a controller for measuring vehicle states, calculating idealized vehicle states using predetermined steering system signals and signals external to the steering system in predetermined state equations, comparing the measured predetermined vehicle states to the idealized vehicle states to isolate signal data of interest and define an estimate of friction present in the steering system, applying friction boundaries to the estimate of friction present in the steering system, and setting an internal software flag for the purpose of acknowledging the presence of high friction in the event the estimate of friction exceeds friction threshold boundaries for a predetermined time threshold. - View Dependent Claims (12, 13, 16, 17)
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- 14. The system as claimed in 13 wherein the controller calculates a confidence factor for the idealized vehicle state for a current vehicle state.
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18. A method for detecting and identifying friction in a vehicle having an electric power steering system, the method comprising the steps of:
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measuring predetermined vehicle states; calculating idealized vehicle states using steering system signals and signals external to the steering system in predetermined state equations; calculating a confidence factor to be applied to the idealized vehicle states to determine valid idealized vehicle states; comparing the measured predetermined vehicle states to the valid idealized vehicle states to isolate signal data of interest and define an estimate of friction present in the steering system; applying friction boundaries to the estimate of friction present in the steering system; qualifying the estimate of friction; and setting an internal software flag for the purpose of acknowledging the presence of high friction in the event the estimate of friction exceeds the friction boundaries for a predetermined amount of time. - View Dependent Claims (19, 20)
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Specification