Detection and reconstruction of roll rate sensor fault

• US 9,873,425 B2
• Filed: 04/13/2016
• Issued: 01/23/2018
• 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, Melek, William, Zarringhalam, Reza
• Primary Examiner(s): CHEUNG, CALVIN K
• Application Number:
  US15/097,542
• Publication Number:
  US 20170297562A1
• Time in Patent Office: 650 Days
• CPC Class Codes: B60T 2210/22 Banked curves
• CPC Class Codes: B60T 2250/06 Sensor zero-point adjustment; Offset compensation
• CPC Class Codes: B60T 2270/406 Test-mode; Self-diagnosis
• CPC Class Codes: B60T 2270/413 Plausibility monitoring, cross check, redundancy
• 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 8/885 using electrical circuitry
• CPC Class Codes: B60W 2050/0215 Sensor drifts or sensor failures
• CPC Class Codes: B60W 2050/0292 Fail-safe or redundant systems, e.g. limp-home or backup systems
• CPC Class Codes: B60W 2420/00 Indexing codes relating to the type of sensors based on the principle of their operation
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/18 Roll
• CPC Class Codes: B60W 2530/10 Weight
• 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 50/029 Adapting to failures or work around with other constraints, e.g. circumvention by avoiding use of failed parts
• CPC Class Codes: B62D 5/0457 characterised by control features of the drive means as such

Abstract

A method of reconstructing a detected faulty signal. A roll sensor fault is detected by a processor. A signal of the detected faulty roll 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 roll sensor fault by a processor;

reconstructing, by the processor, a signal of the detected faulty roll sensor using indirect sensor data; and

outputting the reconstructed signal to a controller to execute a control action on a vehicle system to maintain stability;

wherein detecting the roll sensor fault by the processor comprises the steps of;

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

obtaining sensory data from at least one non-faulted sensor other than the roll sensor,

determining a virtual sensor value as a function of the sensory data from the at least one non-faulted sensor,

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

comparing the residual to a threshold, and

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

2. The method of claim 1 wherein determining a virtual sensor value as a function of the sensory data from the at least one non-faulted sensor is determined utilizing a roll dynamics of a vehicle model and is represented by the following formula:

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

4. The method of claim 1 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 roll rate is determined utilizing the following equation:

T_dφ

=max(T_φ

(k),T_φ

(k−

1) . . . ,T_φ

(k−

W_φ

));

where T_φ

is a respective instantaneous threshold, and where W_φ

is a length of time of the time window during the roll 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 (φ

)}</sub>=B_sφ

+B_dφ

(|a_y|)

where B_sφ

is a static bound that determines a fixed minimum value for the threshold, and B_dφ

is a constant gain that adds effects of lateral excitation to the threshold.

9. The method of claim 1 wherein determining a virtual sensor value of the roll 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 (φ

)})}<sub>−

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

)})}<sub>v−

ij</sub>+R({circumflex over (θ

)}<sub>v−

ij</sub>,{circumflex over (φ

)}<sub>v−

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

)})}<sub>r−

ij</sub>

where {circumflex over ({dot over (φ

)})}<sub>−

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

)})}<sub>v−

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

)}<sub>v−

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

)})}<sub>r−

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

10. The method of claim 9 wherein generating the residual as a function of the sensory data from the faulted roll sensor and the virtual sensor value from the at least one non-faulted sensor is determined by the following equation:

R<sub>{dot over (φ

)}−

ij</sub>=|{dot over (φ

)}_s−

{circumflex over ({dot over (φ

)})}<sub>−

ij</sub>|

wherein {circumflex over ({dot over (φ

)})}<sub>−

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

)}_s measured value from the roll rate sensor.

11. The method of claim 1 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 (φ

)})}=w<sub>−

ij</sub>{circumflex over ({dot over (φ

)})}<sub>−

ij</sub>

where {circumflex over ({dot over (φ

)})} is the reconstructed roll rate signal;

w<sub>−

ij</sub> represent weight factors.

15. The method of claim 1 wherein the outputting the reconstructed signal to a controller includes outputting the signal to a vehicle braking system for mitigating a vehicle instability condition.

16. The method of claim 1 wherein the outputting the reconstructed signal to a controller includes outputting the signal to a powertrain control system for mitigating a vehicle instability condition.

17. The method of claim 1 wherein the outputting the reconstructed signal to a controller includes outputting the signal to a vehicle traction control system for mitigating a vehicle instability condition.

18. The method of claim 1 wherein the outputting the reconstructed signal to a controller includes outputting the signal to a steering system for mitigating a vehicle instability condition.