Controller of electric power steering apparatus

• US 20060282565A1
• Filed: 06/09/2006
• Published: 12/14/2006
• Est. Priority Date: 06/10/2005
• Status: Active Grant

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Kumaido, Kazuhiro, Aoki, Yuho
• Granted Patent: US 7,363,136 B2
• Time in Patent Office: Days
• US Class Current: 710/41
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 5/0493 detecting processor errors, e.g. plausibility of steering direction

Abstract

An initial abnormality analysis data is reliably retained by a controller of an electric power steering apparatus. The controller of the electric power steering apparatus is constituted by comprising abnormality detection means for detecting the abnormality of a steering assist control mechanism comprising an electric motor giving a steering assist force to a steering system and abnormality data storage means for storing abnormality analysis data in storage means when the abnormality of the steering assist control mechanism is detected by this abnormality detection means, wherein the storage means comprises a plurality of overwrite prohibition storage areas for prohibiting the overwrite of the abnormality analysis data and a plurality of overwrite allowable storage areas for overwriting and storing the abnormality analysis data, and wherein the abnormality data storage means stores the abnormality of the steering assist control mechanism detected by the abnormality detection means in the overwrite prohibition storage area when the abnormality is a first abnormality analysis data, and stores the abnormality in the overwrite allowable storage area when the abnormality is the abnormality analysis data subsequent to the second time.

Claims

1. A controller of an electric power steering apparatus, comprising:

a steering assist control mechanism comprising an electric motor giving a steering assist force to a steering system;

abnormality detection means for detecting an abnormality of the steering assist control mechanism; and

abnormality data storage means for storing abnormality analysis data for analyzing the abnormality in storage means when the abnormality of the steering assist control mechanism is detected by the abnormality detection means,

wherein said storage means comprises an overwrite prohibition storage area for prohibiting an overwrite of said abnormality analysis data and an overwrite allowable storage area for overwriting and storing said abnormality analysis data, and

wherein said abnormality data storage means is constituted to store an abnormality of the steering assist control mechanism detected by the abnormality detection means in said overwrite prohibition storage area when the abnormality is a first abnormality analysis data, and store the abnormality in said overwrite allowable storage area when the abnormality is the abnormality analysis data subsequent to the second time.

2. The controller of the electric power steering apparatus according to claim 1, wherein said storage means is constituted by an electrically erasable read-only memory.

3. The controller of the electric power steering apparatus according to claim 1, wherein said abnormality data storage means is constituted to have an initial data discriminating flag set when an initial abnormality analysis data is stored in said storage means, and store the abnormality analysis data as the initial abnormality analysis data in said overwrite prohibition storage area in case said abnormality analysis data is inputted when the initial data discriminating flag is reset, and store the abnormality analysis data in said overwrite allowable storage area as the abnormality analysis data subsequent to the initial abnormality analysis data when the initial data discriminating flag is set.

4. The controller of the electric power steering apparatus according to claim 3, wherein said abnormality data storage means comprises flag reset means for resetting said initial data discriminating flag when an analysis processing of the abnormality analysis data is performed.

5. The controller of the electric power steering apparatus according to claim 1, wherein said storage means has a plurality of overwrite prohibition storage areas.

7. The controller of the electric power steering apparatus according to claim 1, wherein said abnormality data storage means is constituted to retain the abnormality analysis data during a predetermined time before and after the abnormality detection in time sequence.

8. The controller of the electric power steering apparatus according to claim 7, wherein said abnormality analysis data is constituted by the time sequential data of the detection period comprising a first predetermined time leading to the generation of the abnormality and the time sequential data of the confirmation period from the expiry of said detection period to the second predetermined time.

13. The controller of the electric power steering apparatus according to claim 2, wherein said storage means has a plurality of overwrite prohibition storage areas.

18. The controller of the electric power steering apparatus according to claim 7, wherein said initial abnormality detection means is constituted to perform any one or a plurality of the initial abnormality detection of the toque detection means included in said steering assist control mechanism, the initial abnormality detection of the control means included in said steering assist control mechanism, the initial abnormality detection of the current detection means included in said steering assist control mechanism, the initial abnormality detection of the electric motor included in said steering assist control mechanism, the initial abnormality detection of the power supply system and the initial abnormality detection of said memory.

6. A controller of an electric power steering apparatus, comprising:

a steering assist control mechanism comprising an electric motor giving a steering assist force to a steering system;

initial abnormality detection means for detecting an abnormality at the operation starting time of the steering assist control mechanism;

full-time abnormality detection means for detecting the abnormality in fall time after the operation starting time of said steering control mechanism; and

abnormality data storage means for storing the abnormality analysis data for analyzing the abnormality in the storage means when the abnormality is detected by said initial abnormality detection means and said full-time abnormality detection means,

wherein said storage means comprises initial abnormality and full-time abnormality overwrite prohibition storage areas for prohibiting the overwrite of said abnormality analysis data and the initial abnormality and full-time abnormality overwrite allowable storage areas for overwriting and storing the abnormality analysis data individually corresponding to said initial abnormality detection means and said full-time abnormality detection means, and

wherein the abnormality data storage means is constituted to store an abnormality of the steering assist control mechanism detected by said initial abnormality detection means in said initial abnormality overwrite prohibition storage area when the abnormality is an initial abnormality analysis data, and store the abnormality in said initial abnormality overwrite allowable storage area when the abnormality is the initial abnormality analysis data subsequent to the second time, and store the abnormality in said full-time abnormality overwrite prohibition storage area when the abnormality of the steering assist control mechanism detected by said full-time abnormality detection means is an initial abnormality analysis data, and store the abnormality in said full-time abnormality overwrite allowable storage area when the abnormality is the full-time abnormality analysis data subsequent to the second time.

9. The controller of the electric power steering apparatus according to claim 6, wherein said initial abnormality detection means is constituted to perform any one or a plurality of the initial abnormality detection of the toque detection means included in said steering assist control mechanism, the initial abnormality detection of the control means included in said steering assist control mechanism, the initial abnormality detection of the current detection means included in said steering assist control mechanism, the initial abnormality detection of the electric motor included in said steering assist control mechanism, the initial abnormality detection of the power supply system and the initial abnormality detection of said memory.

10. The controller of the electric power steering apparatus according to claim 6, wherein said full-time abnormality detection means is constituted to perform any one or a plurality of the full-time abnormality detection of the toque detection means included in said steering assist control mechanism, the full-time abnormality detection of the control means included in said steering assist control mechanism, the full-time abnormality detection of the current detection means included in said steering assist control mechanism, the full-time abnormality detection of the electric motor included in said steering assist control mechanism, the full-time abnormality detection of the speed detection means included in said steering assist control mechanism and the full-time abnormality detection of the power supply system.

11. The controller of the electric power steering apparatus according to claim 6, comprising data amount managing means for managing the data amount initially stored in said initial abnormality overwrite prohibition storage area and the full-time abnormality overwrite prohibition storage area, and storage data adding means for additionally storing new abnormality analysis data in the initial abnormality overwrite prohibition storage area and the full-time abnormality overwrite prohibition storage area by determining whether or not the abnormality analysis data is storable and if storable based on the data amount managed by said data amount managing means when the abnormality analysis data is generated next.

12. The controller of the electric power steering apparatus according to claim 11, wherein said data managing means is constituted to store and manage the data amount stored in said initial abnormality overwrite prohibition storage area and the full-time abnormality overwrite prohibition storage area in the nonvolatile memory.

14. The controller of the electric power steering apparatus according to claim 6, wherein said abnormality data storage means is constituted to retain the abnormality analysis data during a predetermined time before and after the abnormality detection in time sequence.

15. The controller of the electric power steering apparatus according to claim 14, wherein said abnormality analysis data is constituted by the time sequential data of the detection period comprising a first predetermined time leading to the generation of the abnormality and the time sequential data of the confirmation period from the expiry of said detection period to the second predetermined time.

16. The controller of the electric power steering apparatus according to claim 14, wherein said initial abnormality detection means is constituted to perform any one or a plurality of the initial abnormality detection of the toque detection means included in said steering assist control mechanism, the initial abnormality detection of the control means included in said steering assist control mechanism, the initial abnormality detection of the current detection means included in said steering assist control mechanism, the initial abnormality detection of the electric motor included in said steering assist control mechanism, the initial abnormality detection of the power supply system and the initial abnormality detection of said memory.

17. The controller of the electric power steering apparatus according to claim 14, wherein said full-time abnormality detection means is constituted to perform any one or a plurality of the full-time abnormality detection of the toque detection means included in said steering assist control mechanism, the full-time abnormality detection of the control means included in said steering assist control mechanism, the full-time abnormality detection of the current detection means included in said steering assist control mechanism, the full-time abnormality detection of the electric motor included in said steering assist control mechanism, the full-time abnormality detection of the speed detection means included in said steering assist control mechanism and the full-time abnormality detection of the power supply system.