Update control device, update control system, and update control method

1. An update control device comprising:

a processor to execute a program; and

a memory to store the program which, when executed by the processor, performs processes of,

among a plurality of in-vehicle electronic control units (ECU), inquiring of a dependent in-vehicle ECU having dependency with an update target in-vehicle ECU whether or not an update of the update target in-vehicle ECU can be executed based on a communication state between the dependent in-vehicle ECU and the update target in-vehicle ECU, wherein determining whether or not the update can be executed based on the communication state comprises:

determining that the update can be executed when the communication state between the dependent in-vehicle ECU and the update target in-vehicle ECU corresponds to a first state in which the update target in-vehicle ECU is not currently communicating with dependent in-vehicle ECU, and

determining that the update can be executed when the communication state between the dependent in-vehicle ECU and the update target in-vehicle ECU corresponds to a second state in which the update target in-vehicle ECU does not communicate with the dependent in-vehicle ECU except in a periodic communication cycle;

calculating an update time required for updating the update target in-vehicle ECU;

acquiring a stop time from when a vehicle temporarily stops until the vehicle starts traveling; and

determining whether or not the update of the update target in-vehicle ECU is to be completed within the stop time by comparing the update time with the stop time when a response indicating that the update can be executed is confirmed.

2. The update control device according to claim 1 , wherein the stop time is acquired from an external device.

3. The update control device according to claim 2 , wherein time during which a red signal of a traffic light is turned on or time during which a crossing gate at a railroad crossing is descending is acquired as the stop time from the external device.

4. The update control device according to claim 1 , wherein

the memory stores dependency information indicating dependency between the plurality of in-vehicle ECUs, and

the processes further include identifying the dependent in-vehicle ECU based on the dependency information stored in the memory.

5. The update control device according to claim 1 , wherein the update time is calculated on a basis of a time required for shutting down, starting up, and memory rewriting of the update target in-vehicle ECU.

6. The update control device according to claim 1 , wherein when there is a plurality of the update target in-vehicle ECUs, the processes further include performing, in order of update priority, determinations of each of which is a determination as to whether or not an update of a corresponding one of the update target in-vehicle ECUs is to be completed within the stop time.

7. The update control device according to claim 1 , wherein when there is a plurality of the update target in-vehicle ECUs, the processes further include determining whether or not updates of the respective plurality of update target in-vehicle ECUs are to be completed within the stop time, by calculating a total time of update times calculated for the respective in-vehicle ECUs and comparing the total time with the stop time.

8. The update control device according to claim 1 , wherein when there is a plurality of the update target in-vehicle ECUs and updates thereof are to be performed in parallel, the processes further include determining whether or not the updates of the respective plurality of update target in-vehicle ECUs are to be completed within the stop time, by comparing a longest update time among update times calculated for the respective in-vehicle ECUs with the stop time.

9. An update control system comprising:

the update control device according to claim 1 ; and

each of the plurality of in-vehicle ECUs includes: a processor to execute a program; and a memory to store the program which, when executed by the processor, performs a process of responding to an inquiry about whether or not an update can be executed.

10. The update control device according to claim 1 , further comprising:

determining that the update cannot be executed when the communication state between the dependent ECU and the update target in-vehicle ECU corresponds to a third state in which the update target in-vehicle ECU is currently communicating with the dependent in-vehicle ECU.

11. An update control method comprising:

among a plurality of in-vehicle electronic control units (ECU), inquiring, by a processor, a dependent in-vehicle ECU having dependency with an update target in-vehicle ECU whether or not an update of the update target in-vehicle ECU can be executed based on a communication state between the dependent in-vehicle ECU and the update target in-vehicle ECU, wherein determining whether or not the update can be executed based on the communication state comprising:

determining that the update can be executed when the communication state between the dependent in-vehicle ECU and the update target in-vehicle ECU corresponds to a first state in which the update target in-vehicle ECU is not currently communicating with dependent in-vehicle ECU, and

determining that the update can be executed when the communication state between the dependent in-vehicle ECU and the update target in-vehicle ECU corresponds to a second state in which the update target in-vehicle ECU does not communicate with the dependent in-vehicle ECU except in a periodic communication cycle;

calculating, by the processor, an update time required for updating the update target in-vehicle ECU;

acquiring, by the processor, a stop time from when a vehicle temporarily stops until the vehicle starts traveling; and

determining, by the processor, whether or not the update of the update target in-vehicle ECU is to be completed within the stop time by comparing the update time with the stop time when a response indicating that the update can be executed is confirmed.