Method and system for detecting increased internal friction in a steering mechanism
A method and system for detecting increased internal friction in a steering mechanism of a vehicle having a steering system including a steering linkage and a steering wheel. The method includes detecting a steering acceleration {umlaut over (φ)} L value of an element of the steering system and comparing the steering acceleration {umlaut over (φ)} L value with a stored maximum steering acceleration threshold value {umlaut over (φ)} n, max . Based on the comparison, if the steering acceleration {umlaut over (φ)} L value is greater than the maximum steering acceleration threshold value {umlaut over (φ)} n, max , the method generates at least one first signal r1 for further processing. The method may further include counting a number of events n occurring owning to the first signal r1 and comparing n with a possible maximum number of events nmax. If n is greater than nmax, the method generates a second signal r2.
1. A method for determining increased internal friction of a steering mechanism of a vehicle, having a steering mechanism including a steering linkage and a steering wheel, the method comprising:
detecting a steering acceleration ({umlaut over (φ)} L ) value of one of the steering wheel and the steering linkage of the steering system, using a sensor operatively coupled to the steering mechanism;
comparing the steering acceleration ({umlaut over (φ)} L ) value with a stored maximum steering acceleration threshold value ({umlaut over (φ)} n, max ), the maximum steering acceleration threshold value being independent of a speed of travel of the vehicle; and
if the steering acceleration ({umlaut over (φ)} L ) value is greater than the maximum steering acceleration threshold value ({umlaut over (φ)} n, max ), then generating at least one first signal (r 1 ) for further processing.
2. A method of claim 1 , wherein the maximum steering acceleration threshold value ({umlaut over (φ)} n, max ) is substantially higher than the maximum steering acceleration ({umlaut over (φ)} L )occurring when the steering mechanism is subjected to normal internal friction.
3. The method of claim 1 , wherein the first signal (r 1 ) is used to display a warning signal for the vehicle driver.
4. The method of claim 1 , wherein the first signal (r 1 ) is passed to an Electric Power Assist Steering (EPAS) system.
5. The method of claim 1 , wherein the first signal (r 1 ) is passed to an Electronic Stability Control (ESC) system.
6. The method of claim 1 further comprising:
counting a number of events (n) occurring owing to the first signal (r 1 );
detecting a possible maximum number of events (n max );
comparing (n) with (n max ); and
generating a second signal (r 2 ), if (n) is greater than (n max ).
7. The method of claim 6 , wherein (n max ) is detected and compared with (n) within a predetermined time period (Δt).
8. The method of claim 6 , wherein the first signal (r 1 ) and the second signal (r 2 ) are provided to a low-pass filter.
9. The method of claim 6 , wherein the first signal (r 1 ) and the second signal (r 2 ) are provided to a high-pass filter.
10. The method of claim 1 , wherein the steering acceleration ({umlaut over (φ)} L ) is detected by using one or more of:
a steering wheel rotational angle sensor;
a position sensor;
a speed sensor; or
an acceleration sensor;
wherein the one or more sensors are operatively coupled to the steering mechanism.
11. The method of claim 1 further comprising determining a low level of tire traction.
12. The method of claim 1 further comprising determining increase in internal friction within the steering mechanism of the vehicle.
13. A safety and warning system for determining increased internal friction of a steering mechanism of a vehicle, having a steering system including a steering linkage and a steering wheel, the system comprising:
a sensor operatively coupled to the steering mechanism and configured to detect a steering acceleration ({umlaut over (φ)} L ) value of one of the steering wheel and the steering linkage of the steering system;
a processor configured to compare the steering acceleration ({umlaut over (φ)} L ) value with a stored maximum steering acceleration threshold value ({umlaut over (φ)} n, max ), the maximum steering acceleration threshold value being independent of a speed of travel of the vehicle; and
a first signal generator configured to generate at least one first signal (r 1 ) for further processing, if the steering acceleration ({umlaut over (φ)} L ) value is greater than the maximum steering acceleration threshold value ({umlaut over (φ)} n, max ).
14. The system of claim 13 , wherein the first signal (r 1 ) is used to display a warning signal for the vehicle driver.
15. The system of claim 13 further comprising a second signal generator configured to:
count a number of events (n) occurring owing to the first signal (r 1 );
detect a possible maximum number of events (n max );
compare (n) with ( nmax ); and
generate a second signal (r 2 ), if (n) is greater than (n max ).
16. The system of claim 15 , wherein (n max ) is detected and compared with (n) within a predetermined time period (Δt).
17. The system of claim 13 further comprising one or more of:
a steering wheel rotational angle sensor;
a position sensor;
a speed sensor; or
an acceleration sensor;
wherein the one or more sensors are employed to detect the steering acceleration ({umlaut over (φ)} L ) and are operatively coupled to the steering mechanism.
18. The system of claim 13 , wherein the maximum steering acceleration threshold value ({umlaut over (φ)} n, max ) is substantially higher than the maximum steering acceleration ({umlaut over (φ)} L ) occurring when the steering mechanism is subjected to normal internal friction.