Detection and reconstruction of pitch rate sensor fault

• US 10,000,215 B2
• Filed: 04/13/2016
• Issued: 06/19/2018
• Est. Priority Date: 04/13/2016
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Chen, Shih-Ken, Litkouhi, Bakhtiar B., Khajepour, Amir, Zarringhalam, Reza, Melek, William
• Primary Examiner(s): Mawari, Redhwan K
• Assistant Examiner(s): King, Rodney P
• Application Number:
  US15/097,551
• Publication Number:
  US 20170297584A1
• Time in Patent Office: 797 Days
• Field of Search: 701 41
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 2250/06 Sensor zero-point adjustment; Offset compensation
• CPC Class Codes: B60T 2270/413 Plausibility monitoring, cross check, redundancy
• 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: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters
• CPC Class Codes: B60T 8/17552 responsive to the tire sideslip angle or the vehicle body slip angle
• CPC Class Codes: B60W 2050/0215 Sensor drifts or sensor failures
• CPC Class Codes: B60W 2510/22 Suspension systems
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/16 Pitch
• CPC Class Codes: B60W 2520/18 Roll
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 50/0205 Diagnosing or detecting failures; Failure detection models
• CPC Class Codes: B60W 50/0225 Failure correction strategy
• CPC Class Codes: B62D 15/025 Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation B62D1/28 takes precedence
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory

Abstract

A method of reconstructing a detected faulty signal. A pitch sensor fault is detected by a processor. A signal of the detected faulty pitch sensor is reconstructed using indirect sensor data. The reconstructed signal is output to a controller to maintain stability.

Claims

1. A method of reconstructing a detected faulty signal comprising the steps of:

detecting a pitch sensor fault in a pitch sensor, by a processor, by;

obtaining sensory data from at least one non-faulted sensor other than the pitch sensor; and

determining a virtual sensor value as a function of the sensory data from the at least one non-faulted sensor, wherein determining the virtual sensor value as a function of the sensory data from the at least one non-faulted sensor is determined utilizing a pitch dynamics of a vehicle model and is represented by the following formula;

2. The method of claim 1 wherein detecting the pitch sensor fault by the processor comprises the steps of:

obtaining sensory data from a faulted pitch sensor, the faulted pitch sensor dedicated to monitor a pitch instability condition;

generating a residual as a function of the sensory data from the faulted pitch sensor and the virtual sensor value from the at least one non-faulted sensor;

comparing the residual to a threshold; and

detecting the sensor pitch fault in response to the residual exceeding the threshold.

3. The method of claim 2 wherein an observer used to estimate a pitch state with an unknown input is represented by the following equations:

4. The method of claim 2 wherein the threshold includes an adaptive threshold.

5. The method of claim 4 wherein the adaptive threshold is estimated based on a current driving condition and dynamic region.

6. The method of claim 5 wherein the current driving conditions and dynamic region are determined using the vehicle model and sensory data.

7. The method of claim 4 wherein the adaptive threshold for the pitch rate is determined utilizing the following equation:

T_dθ

=max(T_θ

(k),T_θ

(k−

1) . . . ,T_θ

(k−

W_θ

)),

where T_θ

is a respective instantaneous threshold, and where W_θ

is a length of the time window during the pitch sensing operation to calculate the threshold.

8. The method of claim 7 wherein the instantaneous adaptive threshold is determined utilizing the following equation:

T<sub>{dot over (θ

)}</sub>=B_dθ

+B_dθ

|a_x|,

where a_x is the longitudinal acceleration, B_dθ

determines a fixed static bound for the threshold,

where the constant B_dθ

adds a function of the longitudinal excitations to the threshold.

9. The method of claim 2 wherein determining a virtual sensor value of the pitch rate as a function of the sensory data from the at least one non-faulted sensor is determined utilizing the following equation:

{circumflex over ({dot over (θ

)})}<sub>−

ij</sub>={circumflex over ({dot over (θ

)})}<sub>v−

ij</sub>+R({circumflex over (θ

)}<sub>v−

ij</sub>,{circumflex over (ϕ

)}<sub>v−

ij</sub>){circumflex over ({dot over (Θ

)})}<sub>r−

ij</sub>

where {circumflex over ({dot over (θ

)})}<sub>−

ij</sub> is the estimated vehicle pitch rate in the form of a virtual sensor, {circumflex over ({dot over (θ

)})}<sub>v−

ij</sub> is the estimated body pitch rate calculated using respective vehicle sensors not indexed by ij subscript, R is the rotation matrix describing orientation of vehicle sprung mass with respect to frame reference coordinate system, {circumflex over (θ

)}<sub>v−

ij</sub> is the is the estimated vehicle pitch angle, {circumflex over (ϕ

)}<sub>v−

ij</sub> is the is the estimated vehicle roll angle, and {circumflex over ({dot over (Θ

)})}<sub>r−

ij</sub> is the estimated rate of change of the road grade angle, all calculated using vehicle sensors not indexed by ij subscript.

10. The method of claim 2 wherein generating the residual as a function of the sensory data from the faulted pitch sensor and the virtual sensor value from the at least one non-faulted sensor is determined by the following equation:

R<sub>{dot over (θ

)}−

ij</sub>=|{dot over (θ

)}_s−

{circumflex over ({dot over (θ

)})}<sub>−

ij</sub>|

wherein {circumflex over ({dot over (θ

)})}<sub>−

ij</sub> is the virtual sensor value and {dot over (θ

)}_s measured value from the pitch rate sensor.

11. The method of claim 2 wherein detecting the sensor fault in response to the residual exceeding the threshold further comprises the step of determining whether the fault persists for a period of time.

12. The method of claim 11 wherein determining whether the fault persists for the period of time further comprises the steps of:

incrementing a fault count each time the residual exceeds the adaptive threshold;

detecting the fault when the fault count exceeds a predetermined count threshold.

13. The method of claim 12 wherein the fault count is reset to zero in response to a residual not exceeding the adaptive threshold.

14. The method of claim 1 wherein reconstructing the signal of the detected faulty sensor using indirect sensor data is determined using the following equation:

{circumflex over ({dot over (θ

)})}=w<sub>−

ij</sub>θ

<sub>−

ij</sub>

where {circumflex over ({dot over (θ

)})} is the reconstructed pitch rate signal, and w<sub>−

ij</sub> represent weight factors.

15. The method of claim 1 wherein controlling the vehicle system with the controller to mitigate a vehicle instability condition includes controlling a vehicle braking system with the controller.

16. The method of claim 1 wherein controlling the vehicle system with the controller to mitigate a vehicle instability condition includes controlling a powertrain control system with the controller.

17. The method of claim 1 wherein controlling the vehicle system with the controller to mitigate a vehicle instability condition includes controlling a vehicle traction control system with the controller.

18. The method of claim 1 wherein controlling the vehicle system with the controller to mitigate a vehicle instability condition includes controlling a steering system with the controller.