Fault diagnosis

• US 7,809,986 B2
• Filed: 06/19/2007
• Issued: 10/05/2010
• Est. Priority Date: 08/22/2006
• Status: Expired due to Fees

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: .ANG.slund, Jan, Nyberg, Mattias, Frisk, Erik, Biteus, Jonas
• Primary Examiner(s): GUYTON, PHILIP A
• Application Number:
  US11/765,132
• Publication Number:
  US 20080052559A1
• Time in Patent Office: 1,204 Days
• Field of Search: 714/26, 714/33, 714/47, 702182-185
• US Class Current: 714/26
• CPC Class Codes: G05B 23/0278 Qualitative, e.g. if-then rules; Fuzzy logic; Lookup tables; Symptomatic search; FMEA

Abstract

Health statuses of components expressing a normal, a suspected faulty or a confirmed faulty condition are estimated. Based on results of tests minimal conflicts are identified explaining the test results. Readiness statuses are derived indicating a final value or a non-final value depending on whether or not additional testing of a component is expected to alter the component'"'"'s health status. In case of non-final value[s], future minimal conflicts are identified expressing all combinations of potentially faulty components being consistent with the set of present minimal conflicts. Based on the minimal conflicts, additional tests are determined being potentially capable of producing results that cause the readiness status to be changed to the final value for one or more components. A status report is generated after evaluation of at least one of the additional tests.

Claims

1. A computer apparatus for estimating a status of an entity (150, 200) with a plurality of components (c₁, . . . , c_n) which each is assumed to have a health status (s), the computer apparatus comprising:

a processing unit (110) adapted to receive results ({R_t}) of a set of tests (t₁, . . . , t_x) in respect of the components (c₁, . . . , c_n), and based thereon generate a status report (<

c,s,r>

) reflecting a functional quality of each of said components (c₁, . . . , c_n), wherein the status report (<

c,s,r>

) indicates the health status (s) in the form of a parameter expressing whether the component is normal (N), suspected faulty (SF) or confirmed faulty (CF), the processing unit (110) is adapted to associate a readiness status (r) with each of said components (c₁, . . . , c_n), the readiness status (r) for a component indicating a final value (R) if no additional testing of the component is expected to alter the component'"'"'s present health status (s), and indicating a non-final value (NR) if additional testing of the component may produce test results ({R_t}) altering the component'"'"'s present health status (s), the processing unit (110) is adapted to, based on the received test results ({R_t});

identify a set of present minimal conflicts (Π

)defining a set of health statuses (s) for said components (c₁, . . . , c_n) explaining the test results ({R_t}),

derive a respective readiness status (r) for each of said components (c₁, . . . , c_n), and in case of at least one non-final value (NR),

identify a set of future minimal conflicts (Π

^f) expressing all potential combinations of health statuses (s) for said components (c₁, . . . , c_n) being consistent with the set of present minimal conflicts (Π

),

determine, based on the sets of present and future minimal conflicts (Π

;

Π

^f), a set of additional tests ({t_A}) in which each test is potentially capable of producing a result that causes the processing unit (110) to change the readiness status (r) for at least one of said components (c₁, . . . , c_n) from the non-final value (NR) to the final value (R), and evaluate at least one test in the set of additional tests ({t_A}).

2. The computer apparatus according to claim 1, wherein the processing unit (110) is adapted to evaluate different tests in the set of additional tests ({t_A}) until a readiness status (r) with a final value (R) has been derived in respect of a desired number of said components (c₁, . . . , c_n).

3. The computer apparatus according to claim 1, wherein the processing unit (110) is adapted to receive the test results ({R_t}) via at least two testing agents (A₁, A_x) associated with the entity (150, 200), and the at least two testing agents (A₁, A_x) are included in a distributed testing system for the entity (150, 200).

4. The computer apparatus according to claim 1, wherein at least one test in the set of tests (t₁, . . . , t_x) is a multi-component test adapted to simultaneously check a behavior of at least two of said components (c₁, . . . , c_n).

5. A motor vehicle (200) consisting of a plurality of components (c₁, . . . , c_n, . . . , c_s) and a diagnosis system adapted to estimate functional qualities of at least a sub-group (c₁, . . . , c_n) of said components, wherein the diagnosis system estimates a status of an entity (150, 200) with a plurality of components (c₁, . . . , c_n) which each is assumed to have a health status (s), the diagnosis system comprising:

a processing unit (110) adapted to receive results ({R_t}) of a set of tests (t₁, . . . , t_x) in respect of the components (c₁, . . . , c_n), and based thereon generate a status report (<

c,s,r>

) reflecting a functional quality of each of said components (c₁, . . . , c_n), wherein the status report (<

c,s,r>

) indicates the health status (s) in the form of a parameter expressing whether the component is normal (N), suspected faulty (SF) or confirmed faulty (CF), the processing unit (110) is adapted to associate a readiness status (r) with each of said components (c₁, . . . , c_n), the readiness status (r) for a component indicating a final value (R) if no additional testing of the component is expected to alter the component'"'"'s present health status (s), and indicating a non-final value (NR) if additional testing of the component may produce test results ({R_t}) altering the component'"'"'s present health status (s), the processing unit (110) is adapted to, based on the received test results ({R_t});

identify a set of present minimal conflicts (Π

)defining a set of health statuses (s) for said components (c₁, . . . , c_n) explaining the test results ({R_t}),

derive a respective readiness status (r) for each of said components (c₁, . . . , c_n), and in case of at least one non-final value (NR),

identify a set of future minimal conflicts (Π

^f) expressing all potential combinations of health statuses (s) for said components (c₁, . . . , c_n) being consistent with the set of present minimal conflicts (Π

),

determine, based on the sets of present and future minimal conflicts (Π

;

Π

^f), a set of additional tests ({t_A}) in which each test is potentially capable of producing a result that causes the processing unit (110) to change the readiness status (r) for at least one of said components (c₁, . . . , c_n) from the non-final value (NR) to the final value (R), and

evaluate at least one test in the set of additional tests ({t_A}).

6. A method of estimating a status of an entity (150, 200) with a plurality of components (c₁, . . . , c_n) which each is assumed to have a health status (s), the method comprising receiving results ({R_t}) of a set of tests (t₁, . . . , t_x) in respect of the components (c₁, . . ., c_n), and based thereon generating a status report (<

c,s,r>

) reflecting a functional quality of each of said components (c₁, . . . , c_n), wherein the status report (<

c,s,r>

) indicates the health status (s) in the form of a parameter expressing whether the component is normal (N), suspected faulty (SF) or confirmed faulty (CF), and the method comprising operation of the following elements on a processing unit (110);

associating a readiness status (r) with each of said components (c₁, . . . , c_n) using the processing unit, the readiness status (r) for a component indicating a final value (R) if no additional testing of the component is expected to alter the component'"'"'s present health status (s), and indicating a non-final value (NR) if additional testing of the component may produce test results ({R_t}) altering the component'"'"'s present health status (s), the method further comprising, based the received test results ({R_t}),

identifying via the processing unit a set of present minimal conflicts (Π

)defining a set of health statuses (s) for said components (c₁, . . . , c_n) explaining the test results ({R_t}),

deriving via the processing unit a respective readiness status (r) for each of said components (c₁, . . . , c_n), and in case of at least one non-final value (NR),

identifying via the processing unit a set of future minimal conflicts (Π

^f) expressing all potential combinations of health statuses for said components (c₁, . . . , c_n) being consistent with the set of present minimal conflicts (H),

determining via the processing unit, based on the sets of present and future minimal conflicts (Π

;

Π

^f), a set of additional tests ({t_A}) in which each test is potentially capable of producing a result that causing the readiness status (r) for at least one of said components (c₁, . . . , c_n) to be changed from the non-final value (NR) to the final value (R), and

evaluating via the processing unit at least one test in the set of additional tests ({t_A}).

7. The method according to claim 6, comprising evaluating different tests in the set of additional tests ({t_A}) until a readiness status (r) with a final value (R) has been derived in respect of a desired number of said components (c₁, . . . , c_n).

8. The method according to claim 6, wherein at least one test in the set of tests (t₁, . . . , t_x) is a multi-component test adapted to simultaneously check a behavior of at least two of said components (c₁, . . . , c_n).

9. A computer program product comprising computer-readable storage medium, the computer-readable storage medium comprising computer-executable program code stored therein, the computer-executable program code configured for estimating a status of an entity (150, 200) with a plurality of components (c₁, . . . , c_n) which each is assumed to have a health status (s), the method comprising receiving results ({R_t}) of a set of tests (t₁, . . . , t_x) in respect of the components (c₁, . . . , c_n), and based thereon generating a status report (<

c,s,r>

) reflecting a functional quality of each of said components (c₁, . . . , c_n), wherein the status report (<

c,s,r>

) indicates the health status (s) in the form of a parameter expressing whether the component is normal (N), suspected faulty (SF) or confirmed faulty (CF), and the computer-executable program code comprising;

a first executable portion configured to associate a readiness status (r) with each of said components (c₁, . . . , c_n), the readiness status (r) for a component indicating a final value (R) if no additional testing of the component is expected to alter the component'"'"'s present health status (s), and indicating a non-final value (NR) if additional testing of the component may produce test results ({R_t}) altering the component'"'"'s present health status (s), the computer-executable program code further comprising, based the received test results ({R_t});

a second executable portion configured to identify a set of present minimal conflicts (Π

) defining a set of health statuses (s) for said components (c₁, . . . , c_n) explaining the test results ({R_t}),

a third executable portion configured to derive a respective readiness status (r) for each of said components (c₁, . . . , c_n), and in case of at least one non-final value (NR),

a fourth executable portion configured to identify a set of future minimal conflicts (Π

^f) expressing all potential combinations of health statuses for said components (c₁, . . . , c_n) being consistent with the set of present minimal conflicts (Π

),

a fifth executable portion configured to determine, based on the sets of present and future minimal conflicts (Π

;

Π

^f), a set of additional tests ({t_A}) in which each test is potentially capable of producing a result that causing the readiness status (r) for at least one of said components (c₁, . . . , c_n) to be changed from the non-final value (NR) to the final value (R), and

a sixth executable portion configured to evaluate at least one test in the set of additional tests ({t_A}).

10. The computer program product according to claim 9, wherein said computer-executable program code further comprises:

a seventh executable portion configure to evaluate different tests in the set of additional tests ({t_A}) until a readiness status (r) with a final value (R) has been derived in respect of a desired number of said components (c₁, . . . , c_n).

11. The computer program product according to claim 9, wherein at least one test in the set of tests (t₁, . . . , t_x) is a multi-component test adapted to simultaneously check a behavior of at least two of said components (c₁, . . . , c_n).

12. A computer readable storage medium (160) comprising computer-executable program code stored therein, the computer-executable program code configured for estimating a status of an entity (150, 200) with a plurality of components (c₁, . . . , c_n) which each is assumed to have a health status (s), the method comprising receiving results ({R_t}) of a set of tests (t₁, . . . , t_x) in respect of the components (c₁, . . . , c_n), and based thereon generating a status report (<

c,s,r>

) reflecting a functional quality of each of said components (c₁, . . . , c_n), wherein the status report (<

c,s,r>

) indicates the health status (s) in the form of a parameter expressing whether the component is normal (N), suspected faulty (SF) or confirmed faulty (CF), and the computer-executable program code comprising;

a first executable portion configured to associate a readiness status (r) with each of said components (c₁, . . . , c_n), the readiness status (r) for a component indicating a final value (R) if no additional testing of the component is expected to alter the component'"'"'s present health status (s), and indicating a non-final value (NR) if additional testing of the component may produce test results ({R_t}) altering the component'"'"'s present health status (s), the computer-executable program code further comprising, based the received test results ({R_t});

a second executable portion configured to identify a set of present minimal conflicts (Π

) defining a set of health statuses (s) for said components (c₁, . . . , c_n) explaining the test results ({R_t}),

a third executable portion configured to derive a respective readiness status (r) for each of said components (c₁, . . . , c_n), and in case of at least one non-final value (NR),

a fourth executable portion configured to identify a set of future minimal conflicts (Π

^f) expressing all potential combinations of health statuses for said components (c₁, . . . , c_n) being consistent with the set of present minimal conflicts (Π

),

a fifth executable portion configured to determine, based on the sets of present and future minimal conflicts (Π

;

Π

^f), a set of additional tests ({t_A}) in which each test is potentially capable of producing a result that causing the readiness status (r) for at least one of said components (c₁, . . . , c_n) to be changed from the non-final value (NR) to the final value (R), and

a sixth executable portion configured to evaluate at least one test in the set of additional tests ({t_A}).

13. The computer readable medium according to claim 12, wherein said, computer-executable program code further comprises:

a seventh executable portion configure to evaluate different tests in the set of additional tests ({t_A}) until a readiness status (r) with a final value (R) has been derived in respect of a desired number of said components (c₁, . . . , c_n).

14. The computer readable medium according to claim 12, wherein, wherein at least one test in the set of tests (t₁, . . . , t_x) is a multi-component test adapted to simultaneously check a behavior of at least two of said components (c₁, . . . , c_n).