MESSAGE LOSS PREVENTION IN CAN SYSTEMS

• US 20100180003A1
• Filed: 01/14/2009
• Published: 07/15/2010
• Est. Priority Date: 01/14/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: JIANG, SHENGBING
• Granted Patent: US 9,098,816 B2
• Time in Patent Office: Days
• US Class Current: 709/208
• CPC Class Codes: G05B 2219/25032 CAN, canbus, controller area network bus
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN

Abstract

A method for message loss prevention in a CAN system. The CAN system includes a plurality of distributed nodes, such as electronic control unit nodes that communicate with each other through a CAN bus. The distributed nodes are categorized into a first type node or a second type node. Further, each distributed node has its own task period which is the time taken by a node to complete a task allocated to it. First, a synchronization frequency is determined. Synchronization frames are sent to the second type node by the first type node at the synchronization frequency. Hereafter, task activation synchronization is performed on the second type node based on information included in the synchronization frames where the task activation synchronization is performed by adjusting the task period of the second type node.

Claims

1. A method for preventing message loss in a controller area network (CAN) system, said CAN system including a plurality of distributed nodes capable of communicating with each other through a CAN bus, each of the plurality of distributed nodes being allocated a task, where the plurality of distributed nodes include at least one node of a first type and at least one node of a second type, said method comprising:

determining a synchronization frequency;

sending synchronization frames from the node of the first type to the node of the second type, wherein the synchronization frames are sent at the synchronization frequency; and

performing a task activation synchronization on the node of the second type based on information included in the synchronization frames.

2. The method according to claim 1 wherein determining the synchronization frequency includes modeling the CAN system as a linear hybrid automaton (LHA) and performing an iterative operation on the LHA, wherein the LHA includes a test frequency as a parameter.

3. The method according to claim 2 wherein performing the iterative operation on the LHA includes varying the test frequency by a factor until a condition is met.

4. The method according to claim 3 wherein the condition is fulfilled when a message loss is observed in the LHA.

5. The method according to claim 3 wherein the condition is fulfilled when no message loss is observed in the LHA.

6. The method according to claim 1 wherein the information included in the synchronization frames includes a value of an interval between two instants of time at which successive synchronization frames are sent.

7. The method according to claim 1 wherein each of the plurality of distributed nodes includes a local task period corresponding to the task allocated to it, and wherein the local task period corresponding to one of the plurality of distributed nodes is a time taken by the one of the plurality of distributed nodes to complete the task allocated to it.

8. The method according to claim 1 wherein performing the task activation synchronization includes modifying the local task period of the node of the second type.

9. A method for preventing message loss in a controller-area network (CAN) system, said CAN system including a plurality of distributed nodes capable of communicating with each other through a CAN bus, each of the plurality of distributed nodes being allocated a task, wherein the plurality of distributed nodes include a master node and at least one slave node, said method comprising:

determining a synchronization frequency;

sending synchronization frames from the master node to the at least one slave node, wherein the synchronization frames are sent at the synchronization frequency; and

performing a task activation synchronization on the at least one slave node based on information included in the synchronization frames.

10. The method according to claim 9 wherein determining the synchronization frequency includes modeling the CAN system as a linear hybrid automaton (LHA) and performing an iterative operation on the LHA, wherein the LHA includes a test frequency as a parameter.

11. The method according to claim 10 wherein performing the iterative operation on the LHA includes varying the test frequency by a factor until a condition is met.

12. The method according to claim 11 wherein the condition is fulfilled when a message loss is observed in the LHA.

13. The method according to claim 11 wherein the condition is fulfilled when no message loss is observed in the LHA.

14. The method according to claim 9 wherein determining the synchronization frequency is performed offline.

15. The method according to claim 9 wherein information included in the synchronization frames includes a value of an interval between two instants of time at which successive synchronization frames are sent.

16. The method according to claim 9 wherein each of the plurality of distributed nodes includes a local task period corresponding to the task allocated to it, and wherein the local task period corresponding to one of the plurality of distributed nodes is a time taken by the one of the plurality of distributed nodes to complete the task allocated to it.

17. The method according to claim 9 wherein performing the task activation synchronization comprises modifying the local task period of the at least one slave node.

18. A method for preventing message loss in a CAN system, said CAN system including a plurality of distributed nodes capable of communicating with each other through a CAN bus, each of the plurality of distributed nodes being allocated a task, wherein the plurality of distributed nodes includes a master node and at least one slave node, said method comprising:

determining a synchronization frequency where the synchronization frequency is a frequency at which the master node sends a synchronization frame to the at least one slave node; and

performing task activation synchronization on the at least one slave based on the information included in the synchronization frame.

19. The method according to claim 18 wherein determining the synchronization frequency includes modeling the CAN system as a linear hybrid automaton (LHA) and performing an iterative operation on the LHA, wherein the LHA includes a test frequency as a parameter.

20. The method according to claim 18 wherein information included in the synchronization frames includes a value of an interval between two instants of time at which successive synchronization frames are sent.