Systematic abnormality detection in control commands for controlling power steering system

Patent metadata

Field	Value
Publication number	US-10538267-B2
Application number	US-201715427249-A
Country	US
Kind code	B2
Filing date	Feb 8, 2017
Priority date	Oct 21, 2013
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

An embodiment of a system of a vehicle includes a power steering system that operates as commanded by control commands, and a control module configured to receive a first control command. The control module is also configured to generate a range signal indicative of a range of command values based on a plurality of input signals, generate a second control command based on a subset of the plurality of input signals, determine whether the first control command is out of the range for longer than a predetermined duration of time, and send the second control command to the power steering system in response to determining the first control command is out of the range for longer than the predetermined duration of time.

First claim

The invention claimed is:

1. A system of a vehicle comprising:
a power steering system that operates as commanded by control commands;
a control module configured to:
receive a first control command;
generate a range signal indicative of a range of command values based on a plurality of input signals;
generate a second control command based on a subset of the plurality of input signals;
determine whether the first control command is out of the range for longer than a predetermined duration of time; and
send the second control command to the power steering system in response to determining the first control command is out of the range for longer than the predetermined duration of time, wherein the control module is further configured to:
in response to determining that the first control command is out of the range for shorter than or equal to the predetermined duration of time, limit the first control command to the range, generate a scale factor signal by starting to increase a scale factor from an initial value as soon as the first control command goes out of the range, generate a damping command based on a vehicle velocity signal and the scale factor signal, blend the limited first control command with the damping command, and send the blended command to the power steering system;
in response to determining that the first control command is out of the range for longer than the predetermined duration of time, send the second control command to the power steering system; and
generate an amount of assist torque by the power steering system based on the blended command or the second control command.

2. The system of claim 1 , wherein the control module is further configured to limit the first control command to the range and send the limited first control command to the power steering system in response to determining the first control command is out of the range for shorter than or equal to the predetermined duration of time.

3. The system of claim 1 , wherein the control module is further configured to generate the range signal by varying an upper boundary value of the range and a lower boundary value of the range based on the plurality of input signals.

4. The system of claim 1 , wherein the control module is further configured to synchronize a phase of the range signal and a phase of the first control command.

5. The system of claim 1 , wherein the control module is further configured to:
determine whether the first control command has stayed within the range for longer than another predetermined duration of time while sending out the second control command;
determine whether the first control command and the second control command are within a threshold difference; and
send the first control command to the steering command instead of the second control command if the first control command has stayed within the range for longer than the other predetermined duration of time and if the first control command and the second control command are within the threshold difference.

6. The system of claim 1 , wherein the subset of the plurality of input signals includes at least one of a hand wheel torque signal, a hand wheel angular position signal and a hand wheel velocity signal.

7. The system of claim 1 , wherein the control module is further configured to:
increment a counter in response to determining that the first control command is out of the range;
decrement the counter in response to determining that the first control command is not out of the range;
compare the counter to a threshold counter value;
determine that the first control command is out of range for longer than the predetermined duration of time if the counter is greater than the threshold counter value; and
determine that the first control command is out of range for less than or equal to the predetermined duration of time if the counter is less than or equal to the threshold counter value.

8. The system of claim 1 , wherein the first control command is generated based on at least one of a hand wheel velocity signal and a hand wheel torque signal.

9. A system of a vehicle comprising:
a power steering system that operates as commanded by control commands;
a control module configured to:
receive a first control command;
generate a range signal indicative of a range of command values based on a plurality of input signals;
determine whether the first control command is out of the range for longer than a predetermined duration of time; and
limit the first control command to the range in response to determining that the first control command is out of the range for shorter than or equal to the predetermined duration of time, wherein the control module is further configured to:
in response to determining that the first control command is out of the range for shorter than or equal to the predetermined duration of time, generate a scale factor signal by starting to increase a scale factor from an initial value as soon as the first control command goes out of the range, generate a damping command based on a vehicle velocity signal and the scale factor signal, blend the limited first control command with the damping command, and send the blended command to the power steering system;
in response to determining that the first control command is out of the range for longer than the predetermined duration of time, generate a second control command based on a subset of the plurality of input signals and send the second control command to the power steering system; and
generate an amount of assist torque by the power steering system based on the blended command or the second control command.

10. The system of claim 9 , wherein the control module is further configured to send the limited first control command to the power steering system in response to determining that the first control command is out of the range for shorter than or equal to the predetermined duration of time.

11. The system of claim 9 , wherein the control module is further configured to:
generate a second control command based on a subset of the plurality of input signals; and
send the second control command to the power steering system in response to determining the first control command is out of the range for longer than the predetermined duration of time.

12. The system of claim 11 , wherein the subset of the plurality of input signals includes at least one of a hand wheel torque signal, a hand wheel angular position signal and a hand wheel velocity signal.

13. The system of claim 9 , wherein the control module is further configured to generate the range signal by varying an upper boundary value of the range and a lower boundary value of the range based on the plurality of input signals.

14. The system of claim 9 , wherein the control module is further configured to synchronize a phase of the range signal and a phase of the first control command.

15. The system of claim 9 , wherein the control module is further configured to determine whether the first control command is out of the range for longer than the predetermined duration of time based on using a counter.

16. The system of claim 9 , wherein the control module is further configured to:
increment a counter in response to determining that the first control command is out of the range;
decrement the counter in response to determining that the first control command is not out of the range;
compare the counter to a threshold counter value;
determine that the first control command is out of range for longer than the predetermined duration of time if the counter is greater than the thresho

Assignees

• Steering Solutions Ip Holding
• Bayerische Motoren Werke Ag

Inventors

• Millsap Scott A
• Chandy Ashok
• Derry Kevin L
• Dannöhl Caroline
• Hank Hans-Peter
• Schotte Jens
• Vetter Kristian

Classifications

• B62D5/0493 Primary

  detecting processor errors, e.g. plausibility of steering direction · CPC title

• B62D5/0484 Primary

  for reaction to failures, e.g. limp home · CPC title

• B62D5/049

  detecting sensor failures · CPC title

• B62D5/0481

  monitoring the steering system, e.g. failures · CPC title

• B62D5/0463

  calculating assisting torque from the motor based on driver input · CPC title