A software upgrading system and method for a private CAN bus sub-node

Abstract

The application discloses a kind of private CAN bus subnode's software upgrade system and method, system includes gateway, whole vehicle network node, host computer, public CAN bus, private CAN bus;Method includes S1.host computer sends first function addressing service to main node, and main node receives first function addressing service;S2.main node is forwarded to first function addressing service on CAN bus, and judges whether response, simultaneously, subnode also judges whether response;If main node and subnode are judged as yes, then main node replies positive response to host computer and enters step S3;If main node or subnode is judged as no, then main node replies negative response to host computer and ends this flow;S3.host computer sends request download service to main node, and main node receives request download service;S4.main node judges out update object according to address information in request download service, and executes corresponding update flow according to update object.The application can update program to the subnode of main node on vehicle body bus.

Description

Technical Field

[0001] This invention belongs to the field of software upgrades for CAN bus sub-nodes, specifically relating to a software upgrade system and method for a private CAN bus sub-node. Background Technology

[0002] In the automotive distributed CAN bus communication network architecture, the vehicle main network is connected to most nodes, all of which can use the diagnostic service UDS (Unified Diagnostic Services) on the vehicle main network. For example, software upgrades can be performed directly based on the UDS service defined by ISO 14229 (hereinafter, "$ + number" represents a service, such as $1003). In the automotive domain controller architecture, the vehicle main network only connects a limited number of area controllers and master nodes of various systems. Other child nodes are connected to the private CAN bus of the domain and master nodes. The private CAN bus is independent of the vehicle main network and does not communicate with the vehicle network. The child nodes can only communicate with their master nodes through the private CAN bus. The child nodes do not have independent addresses on the vehicle main network and cannot communicate directly with the vehicle network.

[0003] Patent number CN20181030751003 discloses a method for online code updates of multi-node microcontrollers based on a CAN bus. This method enables simultaneous updates of multiple nodes and allows code updates for different nodes via CAN message IDs. For systems with numerous, difficult-to-disassemble microcontrollers, all node microcontrollers can be connected via a CAN network. It can satisfy both code burning for nodes of the same type and code upgrades for different types of microcontrollers. However, this method cannot utilize diagnostic services for direct software upgrades via the vehicle's main network when updating the application programs of sub-nodes. Summary of the Invention

[0004] The purpose of this invention is to provide a software upgrade system and method for private CAN bus sub-nodes, which can flash and update the application program of the private sub-node of the master node on the vehicle bus without changing the network protocol, message structure and host computer program of the current vehicle bus.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: A software upgrade system for a private CAN bus sub-node includes a gateway, a vehicle network node, a host computer, a common CAN bus, and a private CAN bus. The common CAN bus consists of at least two CAN lines, including a CAN1 line and a CAN2 line. The CAN1 line and the CAN2 line communicate through the gateway. The vehicle network node includes a master node and sub-nodes. One end of the master node is connected to the CAN2 line, and the master node communicates with the host computer through the CAN2 line. The other end of the master node is connected to the private CAN bus, and the master node communicates with multiple sub-nodes through the private CAN bus.

[0006] This invention discloses a software upgrade system for a private CAN bus sub-node. The sub-node communicates via the master node's private CAN bus, which is not interconnected with the vehicle network. When the target to be updated is a sub-node, the host computer, acting as the update source, can complete the software update of the sub-node through the vehicle network using a conventional update process. Furthermore, this process can be completed without changing the host computer program or the CAN message structure. The master node only needs to distinguish the memory address to be written to identify the private sub-node to be upgraded and forward the writing data from the host computer, thereby completing the update of the sub-node's application program. This improves the efficiency of testing and provides convenience for subsequent node maintenance.

[0007] Preferably, the private CAN bus includes a CAN3 line; the vehicle network nodes include a master node A, a child node A1, and a child node A2; one end of the master node A is connected to the CAN2 line, and the master node A communicates with the host computer through the CAN2 line; the other end of the master node A is connected to the CAN3 line; the master node A communicates with the child node A1 and the child node A2 through the CAN3 line.

[0008] This invention also provides a software upgrade method for a private CAN bus sub-node, applied to the aforementioned software upgrade system for a private CAN bus sub-node; the software upgrade method includes: Step S1. The host computer sends the first function addressing service to the master node, and the master node receives the first function addressing service; Step S2. The master node forwards the first function addressing service to the CAN bus and determines whether to respond. At the same time, the child node also determines whether to respond. If both the master node and the child node determine yes, the master node replies to the host computer with a positive response and proceeds to step S3. If either the master node or the child node determines no, the master node replies to the host computer with a negative response and ends the process. Step S3. The host computer sends a request to the master node to download the service, and the master node receives the request to download the service. Step S4. The master node determines the update object based on the flash address information contained in the request download service, and executes the corresponding update process according to the update object.

[0009] Preferably, step S4 includes the following steps: Step S3.1. After receiving the download service request sent by the host computer, the master node determines whether the update object is the master node or a child node based on the address information in the download service request; if the update object is the master node, proceed to step S3.2; if the update object is a child node, proceed to step S3.3. Step S3.2. The host computer executes the first update process on the master node; Step S3.3. The master node performs the second update process on the child nodes.

[0010] Preferably, step S3.2 includes the following steps: Step S3.2.1. The host computer sends a second function addressing service to enable the vehicle network nodes to enter extended session mode; Step S3.2.2. The host computer sends a physical addressing service to read the part number and version number of the node to be updated in the vehicle network. Step S3.2.3. The host computer sends a third-function addressing service to enable the vehicle network nodes to close application messages and diagnostic messages.

[0011] Preferably, step S3.2 further includes the following steps: Step S3.2.4. The host computer sends the first update service to enable the master node to enter the programming session mode; the host computer sends the second update service to remove the security access restrictions of the master node; the host computer sends the third update service to enable the master node to write the fingerprint information. Step S3.2.5. The host computer sends the fourth update service to make the master node request to download the first software update program. The host computer sends the fifth update service to make the master node download the data of the first software update program. The host computer sends the sixth update service to make the master node stop downloading data. The host computer sends the seventh update service to make the master node verify the downloaded data. Step S3.2.6. Repeat step 3.2.5 until the master node finishes downloading the first software update program; Step S3.2.7. The host computer sends the third update service again to make the master node write the write record; Step S3.2.8. The host computer sends the fourth function addressing service to restart the vehicle network nodes.

[0012] Preferably, step S3.3 includes the following steps: Step S3.3.1. The master node sends the first update service to the child node to put it into programming session mode; Step S3.3.2. The master node sends a second update service to the child node to remove the security access restriction; Step S3.3.3. The master node sends the third update service to the child node to write the fingerprint information; Step S3.3.4. The master node sends the fourth update service to the child node, causing it to request the download of the second software update program.

[0013] Preferably, step S3.3 further includes the following steps: Step S3.3.5. The host computer sends the fifth update service to the master node, and the master node forwards the fifth update service to the child nodes so that they can download the data of the first software update program; Step S3.3.6. The host computer sends the sixth update service to the master node, and the master node forwards the sixth update service to the child node to end the data download; Step S3.3.7. The host computer sends the seventh update service to the master node, and the master node forwards the seventh update service to the child nodes to verify the downloaded data; Step S3.3.8. Repeat steps S3.3.5 to S3.3.7 until the child node finishes downloading the second software update program; Step S3.3.9. The host computer sends the fourth function addressing service to the master node, and the master node forwards the fourth function addressing service to the child node to restart the child node.

[0014] Preferably, in step S2, the master node replies with a negative response to the host computer and sends a negative code to the host computer.

[0015] Preferably, the software upgrade method further defines different child node application start addresses; in step S4, the master node judges the address information in the request download service to determine the target child node to be upgraded.

[0016] Beneficial effects: This invention discloses a software upgrade system and method for a private CAN bus sub-node. The sub-node communicates via the master node's private CAN bus, which is not interconnected with the vehicle network. When the target to be updated is a sub-node, the host computer, acting as the update source, can complete the software update of the sub-node through the vehicle network using a conventional update process. Furthermore, this process can be completed without changing the host computer program or the CAN message structure; the master node only needs to distinguish the memory address to be written to identify the private sub-node to be upgraded and forward the writing data from the host computer, thereby completing the update of the sub-node's application program. This improves the efficiency of testing and provides convenience for subsequent node maintenance. Attached Figure Description

[0017] Figure 1The diagram shown is a structural block diagram of a software upgrade system for a private CAN bus sub-node according to Embodiment 1. Figure 2 The above is a flowchart of a software upgrade method for a private CAN bus sub-node according to Embodiment 2. Figure 3 The diagram shown is the first sub-flowchart of a software upgrade method for a private CAN bus sub-node according to Embodiment 2. Figure 4 The diagram shown is the second sub-flowchart of a software upgrade method for a private CAN bus sub-node according to Embodiment 2. Figure 5 The diagram shown is the third sub-flowchart of a software upgrade method for a private CAN bus sub-node according to Embodiment 2. Detailed Implementation

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0019] The technical solution of the present invention will be described in detail below with specific embodiments.

[0020] Example 1 like Figure 1 As shown, this embodiment provides a software upgrade system for a private CAN bus sub-node, including a gateway, a vehicle network node, a host computer, a common CAN bus, and a private CAN bus; the common CAN bus consists of at least two CAN lines, including CAN1 line and CAN2 line; CAN1 line and CAN2 line communicate through the gateway; the vehicle network node includes a master node and sub-nodes; one end of the master node is connected to the CAN2 line, and the master node communicates with the host computer through the CAN2 line; the other end of the master node is connected to the private CAN bus, and the master node communicates with multiple sub-nodes through the private CAN bus.

[0021] Preferably, the private CAN bus includes a CAN3 line; the vehicle network nodes include a master node A, a sub-node A1, and a sub-node A2; one end of the master node A is connected to the CAN2 line, and the master node A communicates with the host computer through the CAN2 line; the other end of the master node A is connected to the CAN3 line; the master node A communicates with the sub-nodes A1 and A2 through the CAN3 line.

[0022] Specifically, in this embodiment, the host computer sends a function addressing service to the master node A to determine whether the master node A, child node A1, or child node A2 needs a software upgrade.

[0023] Furthermore, in this embodiment, the public CAN bus serves as the vehicle network, and the child nodes communicate through the private CAN bus of the master node. The private CAN bus is not interconnected with the vehicle network, and the private child nodes do not have addresses on the vehicle network. Under normal circumstances, the host computer cannot distinguish between different child nodes.

[0024] Furthermore, this embodiment of a software upgrade system for a private CAN bus sub-node defines different application start addresses for sub-nodes. During software upgrades, the master node determines the software flashing address to identify the target sub-node to be upgraded, thereby performing the software upgrade. This allows for software updates of applications on sub-nodes on the private CAN bus of a node using conventional flashing methods on the vehicle's main network, without altering the current network protocol and message structure of the vehicle's bus.

[0025] Furthermore, the software upgrade system for a private CAN bus sub-node in this embodiment is applicable to domain controllers, air conditioning controllers, thermal management modules, etc., which are mounted on the vehicle network, have a private CAN bus, and have one or more sub-nodes mounted on the private bus, and the sub-nodes cannot communicate with the vehicle network.

[0026] Example 2 This embodiment provides a software upgrade method for a private CAN bus sub-node, applied to a software upgrade system for a private CAN bus sub-node in Embodiment 1; such as Figure 2 As shown, the software upgrade methods include: Step S1. The host computer sends the first function addressing service to the master node, and the master node receives the first function addressing service; Step S2. The master node forwards the first function addressing service to the CAN bus and determines whether to respond. At the same time, the child node also determines whether to respond. If both the master node and the child node determine yes, the master node replies to the host computer with a positive response and proceeds to step S3. If either the master node or the child node determines no, the master node replies to the host computer with a negative response and ends the process. Step S3. The host computer sends a request to the master node to download the service, and the master node receives the request to download the service. Step S4. The master node determines the update object based on the flash address information contained in the request download service, and executes the corresponding update process according to the update object.

[0027] Preferably, step S4 includes the following steps: Step S3.1. After receiving the download service request sent by the host computer, the master node determines whether the update object is the master node or a child node based on the address information in the download service request; if the update object is the master node, proceed to step S3.2; if the update object is a child node, proceed to step S3.3. Step S3.2. The host computer executes the first update process on the master node; Step S3.3. The master node performs the second update process on the child nodes.

[0028] Preferably, step S3.2 includes the following steps: Step S3.2.1. The host computer sends a second function addressing service to enable the vehicle network nodes to enter extended session mode; Step S3.2.2. The host computer sends a physical addressing service to read the part number and version number of the node to be updated in the vehicle network. Step S3.2.3. The host computer sends a third-function addressing service to enable the vehicle network nodes to close application messages and diagnostic messages.

[0029] Preferably, step S3.2 further includes the following steps: Step S3.2.4. The host computer sends the first update service to enable the master node to enter the programming session mode; the host computer sends the second update service to remove the security access restrictions of the master node; the host computer sends the third update service to enable the master node to write the fingerprint information. Step S3.2.5. The host computer sends the fourth update service to make the master node request to download the first software update program. The host computer sends the fifth update service to make the master node download the data of the first software update program. The host computer sends the sixth update service to make the master node stop downloading data. The host computer sends the seventh update service to make the master node verify the downloaded data. Step S3.2.6. Repeat step 3.2.5 until the master node finishes downloading the first software update program; Step S3.2.7. The host computer sends the third update service again to make the master node write the write record; Step S3.2.8. The host computer sends the fourth function addressing service to restart the vehicle network nodes.

[0030] Preferably, step S3.3 includes the following steps: Step S3.3.1. The master node sends the first update service to the child node to put it into programming session mode; Step S3.3.2. The master node sends a second update service to the child node to remove the security access restriction; Step S3.3.3. The master node sends the third update service to the child node to write the fingerprint information; Step S3.3.4. The master node sends the fourth update service to the child node, causing it to request the download of the second software update program.

[0031] Preferably, step S3.3 further includes the following steps: Step S3.3.5. The host computer sends the fifth update service to the master node, and the master node forwards the fifth update service to the child nodes so that they can download the data of the first software update program; Step S3.3.6. The host computer sends the sixth update service to the master node, and the master node forwards the sixth update service to the child node to end the data download; Step S3.3.7. The host computer sends the seventh update service to the master node, and the master node forwards the seventh update service to the child nodes to verify the downloaded data; Step S3.3.8. Repeat steps S3.3.5 to S3.3.7 until the child node finishes downloading the second software update program; Step S3.3.9. The host computer sends the fourth function addressing service to the master node, and the master node forwards the fourth function addressing service to the child node to restart the child node.

[0032] Preferably, in step S2, the master node replies with a negative response to the host computer and sends a negative code to the host computer.

[0033] Preferably, the software upgrade method also defines different child node application start addresses; in step S4, the master node judges the address information in the request download service to determine the target child node to be upgraded.

[0034] Specifically, in this embodiment, the host computer sends the following functions: the first function addressing service is $10 03, the second function addressing service is $85 02, the third function addressing service is $28 03 01, and the fourth function addressing service is $11 01; the host computer sends the following update services: the first update service is $10 02, the second update service is $27, the third update service is $2E, the fourth update service is $34, the fifth update service is $36, the sixth update service is $37, and the seventh update service is $31; and the host computer sends the following request download service: $34.

[0035] Specifically, in this embodiment, the object sent by the host computer is the master node A, and the child nodes that communicate with the master node A through the private CAN bus are A1 and A2.

[0036] Specifically, the software upgrade method in this embodiment is mainly divided into three stages: the software update preparation stage, the software update target determination stage, and the sub-node software update stage, as follows: (1) During the software update preparation phase, when the master node A receives the function addressing service sent by the host computer, such as $1003, $85 02, $28 03 01, it forwards it to the private CAN bus and waits for the replies from the child nodes A1, A2, etc. If it and all child nodes reply with a positive response, the node replies with a positive response to the host computer. If there is at least one negative response, the node needs to reply with a negative response and send it to the host computer along with the negative code. (2) Software update target judgment stage: When the master node A receives the $34 service sent by the host computer, it judges the software update target based on the address information in the $34 service (the complete content of the $34 service is $30 00 44 xx xx xx xx yy yy yy yy, where XX is the memory writing start address and yy is the size of the updated software). Since the memory start addresses of the application software A, A1, A2... are all different, the master node A can identify the target node to be updated. If the target to be updated is the master node A, the first update process in step S3.2 is executed until the end; if the target to be written is a private child node A1, A2..., the master node A program jumps to the second software update program dedicated to the child node update software to perform the software update process for the child node. (3) During the sub-node software update phase, taking A1 as an example, master node A sends $10 02 service to A1 to put A1 into programming session mode, sends $27 service to remove security access restrictions, sends $2E service to write the fingerprint information, and sends $34 service to request download. During this period, master node A replies to the host computer with a 0x78 negative code of $34 to make it wait. If sub-node A1 responds negatively during this process, master node A replies to the host computer with a $34 negative response; otherwise, master node A replies to the host computer with a $34 positive response. Then, master node A forwards the host computer's $36 service (request transmission), $37 service (request to exit transmission), $31 service (verification), and $2E service (write refresh information) to sub-node A1, and forwards sub-node A1's reply at the same time. After successful flashing, it forwards the $11 01 (ECU restart) service to complete the flashing process.

[0037] Furthermore, if the target to be updated is determined to be master node A during the software update target determination stage, then the first update process in step S3.2 is executed. When the host computer executes the first update process for master node A in step S3.2, it mainly consists of three stages: the software update preparation stage, the software update flashing stage, and the software update completion stage, as follows: (1) During the software update preparation phase, the host computer uses function addressing to send the $10 03 service to enable the vehicle network node to enter the extended session mode, and uses physical addressing to send the $22 service to read the part number, version number and other related information of the node to be updated; it uses function addressing to send the $85 02 service to close the application message and sends the $28 03 01 service to close the diagnostic message. (2) During the software update flashing stage, the host computer sends $10 02 service to enable the node to enter the programming session mode, sends $27 service to remove the security access restriction, sends $2E service to write the flashing fingerprint information, sends $34 service to request the download of FlashDriver, sends $36 service to transmit data, sends $37 service to end the transmission process, sends $31 service to verify the downloaded data, and repeats $34, $36, $37 and $31 services to download the first software update program.

[0038] (3) At the end of the software update stage, the host computer sends $2E service to write the write record, and finally uses function addressing to send $11 01 to restart the nodes on the vehicle network.

[0039] Specifically, in this embodiment, the child nodes communicate via the master node's private CAN bus, which is not interconnected with the vehicle network. When the target to be updated is a child node, the host computer, acting as the update source, can complete the software update of the child node through the vehicle network using the conventional update process. In this process, it is possible to achieve the update of the child node's application without changing the host computer program or the CAN message structure. The master node only needs to judge and distinguish the memory address to be written, thereby identifying the private child node to be upgraded and forwarding the writing data from the host computer. This improves the efficiency of testing and provides convenience for the maintenance of the nodes in the future.

[0040] The embodiments of the software upgrade system and method for a private CAN bus sub-node provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention, and the descriptions of the embodiments above are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A software upgrade system for a private CAN bus sub-node, characterized in that, The system includes a gateway, vehicle network nodes, a host computer, a common CAN bus, and a private CAN bus. The common CAN bus consists of at least two CAN lines, including CAN1 and CAN2. The CAN1 and CAN2 lines communicate through the gateway. The vehicle network nodes include master nodes and child nodes. One end of the master node is connected to the CAN2 line, and the master node communicates with the host computer through the CAN2 line. The other end of the master node is connected to the private CAN bus, and the master node communicates with multiple child nodes through the private CAN bus. The common CAN bus serves as the vehicle network, and the child nodes communicate through the master node's private CAN bus. The private CAN bus is not interconnected with the vehicle network, and the private child nodes do not have addresses on the vehicle network. The host computer cannot distinguish between different child nodes. The software upgrade system is used to execute a software upgrade method for a private CAN bus sub-node, the software upgrade method including the following steps: Step S1. The host computer sends the first function addressing service to the master node, and the master node receives the first function addressing service; Step S2. The master node forwards the first function addressing service to the CAN bus and determines whether to respond. At the same time, the child node also determines whether to respond. If both the master node and the child node determine yes, the master node replies to the host computer with a positive response and proceeds to step S3. If either the master node or the child node determines no, the master node replies to the host computer with a negative response and ends the process. Step S3. The host computer sends a request to the master node to download the service, and the master node receives the request to download the service. Step S4. The master node determines the update object based on the flash address information contained in the request download service, and executes the corresponding update process according to the update object; Step S4 includes the following steps: Step S3.

1. After receiving the download service request sent by the host computer, the master node determines whether the update object is the master node or a child node based on the address information in the download service request; if the update object is the master node, proceed to step S3.2; if the update object is a child node, proceed to step S3.

3. Step S3.

2. The host computer executes the first update process on the master node; Step S3.

3. The master node performs the second update process on the child nodes.

2. The software upgrade system according to claim 1, characterized in that, The private CAN bus includes a CAN3 line; the vehicle network nodes include a master node A, a child node A1, and a child node A2; one end of the master node A is connected to the CAN2 line, and the master node A communicates with the host computer through the CAN2 line; the other end of the master node A is connected to the CAN3 line; the master node A communicates with the child node A1 and the child node A2 through the CAN3 line.

3. A software upgrade method for a private CAN bus sub-node, characterized in that, A software upgrade system for a private CAN bus sub-node as described in any one of claims 1 to 2; The software upgrade method includes: Step S1. The host computer sends the first function addressing service to the master node, and the master node receives the first function addressing service; Step S2. The master node forwards the first function addressing service to the CAN bus and determines whether to respond. At the same time, the child node also determines whether to respond. If both the master node and the child node determine yes, the master node replies to the host computer with a positive response and proceeds to step S3. If either the master node or the child node determines no, the master node replies to the host computer with a negative response and ends the process. Step S3. The host computer sends a request to the master node to download the service, and the master node receives the request to download the service. Step S4. The master node determines the update object based on the flash address information contained in the request download service, and executes the corresponding update process according to the update object; Step S4 includes the following steps: Step S3.

1. After receiving the download service request sent by the host computer, the master node determines whether the update object is the master node or a child node based on the address information in the download service request; if the update object is the master node, proceed to step S3.2; if the update object is a child node, proceed to step S3.

3. Step S3.

2. The host computer executes the first update process on the master node; Step S3.

3. The master node performs the second update process on the child nodes.

4. The software upgrade method according to claim 3, characterized in that, Step S3.2 includes the following steps: Step S3.2.

1. The host computer sends a second function addressing service to enable the vehicle network nodes to enter extended session mode; Step S3.2.

2. The host computer sends a physical addressing service to read the part number and version number of the node to be updated in the vehicle network. Step S3.2.

3. The host computer sends a third-function addressing service to enable the vehicle network nodes to close application messages and diagnostic messages.

5. The software upgrade method according to claim 4, characterized in that, Step S3.2 further includes the following steps: Step S3.2.

4. The host computer sends the first update service to enable the master node to enter the programming session mode; the host computer sends the second update service to remove the security access restrictions of the master node; the host computer sends the third update service to enable the master node to write the fingerprint information. Step S3.2.

5. The host computer sends the fourth update service to make the master node request to download the first software update program. The host computer sends the fifth update service to make the master node download the data of the first software update program. The host computer sends the sixth update service to make the master node stop downloading data. The host computer sends the seventh update service to make the master node verify the downloaded data. Step S3.2.

6. Repeat step 3.2.5 until the master node finishes downloading the first software update program; Step S3.2.

7. The host computer sends the third update service again to make the master node write the write record; Step S3.2.

8. The host computer sends the fourth function addressing service to restart the vehicle network nodes.

6. The software upgrade method according to claim 5, characterized in that, Step S3.3 includes the following steps: Step S3.3.

1. The master node sends the first update service to the child node to put it into programming session mode; Step S3.3.

2. The master node sends a second update service to the child node to remove the security access restriction; Step S3.3.

3. The master node sends the third update service to the child node to write the fingerprint information; Step S3.3.

4. The master node sends the fourth update service to the child node, causing it to request the download of the second software update program.

7. The software upgrade method according to claim 6, characterized in that, Step S3.3 further includes the following steps: Step S3.3.

5. The host computer sends the fifth update service to the master node, and the master node forwards the fifth update service to the child nodes so that they can download the data of the first software update program; Step S3.3.

6. The host computer sends the sixth update service to the master node, and the master node forwards the sixth update service to the child node to end the data download; Step S3.3.

7. The host computer sends the seventh update service to the master node, and the master node forwards the seventh update service to the child nodes to verify the downloaded data; Step S3.3.

8. Repeat steps S3.3.5 to S3.3.7 until the child node finishes downloading the second software update program; Step S3.3.

9. The host computer sends the fourth function addressing service to the master node, and the master node forwards the fourth function addressing service to the child node to restart the child node.

8. The software upgrade method according to claim 3, characterized in that, In step S2, the master node replies with a negative response to the host computer and sends a negative code to the host computer.

9. The software upgrade method according to claim 3, characterized in that, The software upgrade method also defines different starting addresses for child node applications; in step S4, the master node judges the address information in the request download service to determine the target child node to be upgraded.

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