CN107819618B - A method for diagnosing abnormal communication of small satellite voting type - Google Patents

Abstract

A voting type communication abnormity diagnosis method for a small satellite relates to a voting type communication abnormity diagnosis method for the small satellite, and solves the problems that the existing satellite-borne computer diagnosis method has a single point diagnosis point, is easy to generate faults, and has false alarms and missing reports. Designing a diagnosis mechanism of multi-host combined voting on a CAN bus in a daisy chain topology mode, communicating in a CAN bus broadcasting mode, designing a diagnosis broadcast frame protocol and voting of a single-machine communication state in a time-limited response mode; setting N nodes on a CAN bus, and sequentially carrying out cyclic communication; each node has four working states, namely a signature state, a voting state, an inquiry state and an isolation state; summarizing the communication states of the N-1 nodes to complete voting on a certain node; after a certain node is voted to be abnormal, a voting group can be isolated, and the voting group still has the diagnosis capability after the certain node is isolated; the node number in the voting group is dynamically updated along with the change of the node state, and the voting group has higher adaptability and expansibility.

Description

A method for diagnosing abnormal communication of small satellite voting type

technical field

The invention relates to a small satellite voting type communication abnormality diagnosis method.

Background technique

At present, the onboard autonomous communication abnormality diagnosis technology in the satellite field usually adopts the method of adding an abnormality diagnosis module to the onboard computer software. The diagnosis method has the following defects: the main function of the onboard computer is to complete the satellite on-orbit flight mission, and the abnormal diagnosis module occupies too many resources, which will affect the execution of the normal flight mission of the satellite; This constitutes a "single point" diagnostic point. When the onboard computer is disturbed by harsh environments such as noise, electromagnetic interference, space particle radiation, and vibration, or when the communication module of the onboard computer is abnormal, false alarms and false alarms will occur. . Therefore, it is necessary to develop a communication abnormality diagnosis method that avoids the "single point" diagnosis point and has high reliability.

SUMMARY OF THE INVENTION

The invention provides a small satellite voting type communication abnormality diagnosis method to solve the problems of "single point" diagnosis point, easy occurrence of faults, false alarms and omissions in the existing on-board computer diagnosis method.

A small satellite voting type communication abnormality diagnosis method, the method designs a multi-host joint voting diagnosis mechanism on the CAN bus of the daisy chain topology, and adopts the CAN bus broadcast mode to communicate, designs a set of diagnosis broadcast frame protocols, and adopts a time-limited response. way to realize the voting of the single-machine communication status;

The specific diagnosis process is as follows:

It is set that there are N nodes on the CAN bus, and the adjacent two nodes are set as forward nodes and backward nodes in the order of node numbers from small to large, and all normal working nodes form a voting group, which circulates in sequence ; N is a positive integer and N≤16;

Each node has four working states, namely signature state, voting state, challenge state and isolation state;

Signature state: After the node is initially powered on or changes from abnormal communication to normal communication, it enters the signature state by default. According to its own node number, each node sends the CAN message to the CAN after receiving the signature frame, voting frame of the forward node or reaching the sending timeout time. The signature frame is broadcast on the bus, indicating that the node is in a normal communication state;

Voting status:

After completing the sending of the signature frame, the node enters the voting state. According to the receiving state of the voting frame on the CAN bus and the status of each node in the data field of the voting frame, after receiving the voting frame of the forward node or the timeout time, the broadcast sends The voting frame of the backward node; if no abnormal state occurs, the node on the CAN bus always works in the voting state; if the isolation frame sent by other nodes is received, the node in the isolated state will be removed from the voting group during voting, and the bus The total number of nodes on the bus is -1; if a node in the signature state is voted as normal, it will be added to the voting group during voting, and the total number of nodes on the bus will be +1;

Inquiry state:

After a node has been voted abnormal by the forward node for three consecutive times, it is determined that the node is an abnormal node. The abnormal node and its forward node enter the query state at the same time. The forward node sends a query frame to the backward node, and the backward node After receiving the challenge frame, it returns a challenge response frame. If the backward node returns a challenge response frame, both the backward node and its forward node return to the voting state, and the voting group continues the voting process; if the backward node is questioned three times in a row, no In response, the forward node broadcasts the isolation frame to the CAN bus, isolates the backward node from the voting group, and the backward node enters the isolation state; the forward node returns to the voting state after sending the isolation frame;

Isolated state:

Nodes in the isolated state cannot send data and cannot participate in voting. When the isolated node resumes normal communication, it enters the signature state by default.

Beneficial effects of the present invention: The communication abnormality diagnosis method of the present invention integrates the communication status information obtained by multiple nodes on the satellite, votes out the communication status of a certain node, and confirms the node failure through inquiry, avoiding the traditional method. Due to the failure of the abnormal diagnosis computer, the whole star cannot make a judgment on the abnormal state, which effectively avoids the "single point" danger point and improves the on-orbit reliability of the whole star; when voting, it can summarize the data except the voted node. N-1 nodes receive state information, complete the voting on the abnormal state of the voted node, and improve the reliability of fault diagnosis; the working state of the node is expressed by four states, and after a node is abnormal, it can be isolated. In the voting group, after a node is isolated in the voting process, other nodes on the CAN bus still have the ability to diagnose communication abnormalities; the number of nodes in the communication network is dynamically updated with changes in node status, which has higher adaptability and scalability.

Description of drawings

Fig. 1 is a schematic diagram of voting-level members in a small satellite voting-type communication abnormality diagnosis method according to the present invention;

Fig. 2 is a node working state transition diagram in a small satellite voting type communication abnormality diagnosis method according to the present invention;

3 is a schematic diagram of the definition of an arbitration domain in a small satellite voting type communication abnormality diagnosis method according to the present invention;

4 is a flow chart of system power-on initialization in a small satellite voting type communication abnormality diagnosis method according to the present invention;

5 is a flowchart of a communication fault voting abnormality in a small satellite voting type communication abnormality diagnosis method according to the present invention;

Fig. 6 is the inquiry flow chart in a kind of small satellite voting type communication abnormality diagnosis method according to the present invention;

FIG. 7 is a flow chart of node recovery in a method for diagnosing abnormality in small satellite voting type communication according to the present invention.

Detailed ways

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 1. This embodiment is described with reference to FIGS. 1 to 7 , and a small satellite voting type communication abnormality diagnosis method is designed, that is, a multi-computer cooperative voting method based on the CAN bus communication network on the microsatellite satellite to realize the communication abnormality diagnosis of stand-alone components This method designs a multi-host joint voting diagnosis mechanism on the CAN bus in the daisy-chain topology, and uses the CAN bus broadcast communication to design a set of diagnostic broadcast frame protocols and time-limited response to realize the voting of the single-computer communication status.

There are N nodes participating in the voting on a CAN bus network, N is a positive integer and N≤16; the voting process is the voting of the forward node after the completion of the forward node, and finally the Nth node completes the voting of the first node. In each voting cycle, all nodes will send data once. After receiving the data frame, the corresponding status bit count is incremented by 1, and the voting information is sent to the bus when communicating with the node. If the communication of a single-machine component is abnormal, the information of other N-1 nodes is aggregated to generate a voting result, and the voting results are divided into two types: normal and abnormal. According to the system's requirements for fault diagnosis, the minimum number of nodes participating in voting can be set. For example, in a 7-node system, only 2 node information can be used for voting.

All nodes on the CAN bus form a voting group. Figure 1 shows a voting group composed of N nodes. Every two consecutive nodes are called forward nodes and backward nodes respectively. The default communication order is the order of node numbers from small to large, and the communication is cyclic in turn; if a node times out, it will communicate with the node autonomously.

Each node is designed with four working states, namely signature state, voting state, challenge state and isolation state; each state can reflect the current communication status of the node.

Signature state: After the node is initially powered on or changes from abnormal communication to normal communication, it enters the signature state by default. According to its own node number, each node sends the CAN message to the CAN after receiving the signature frame, voting frame of the forward node or reaching the sending timeout time. The signature frame is broadcast on the bus, indicating that the node is in a normal communication state;

Voting status:

After completing the sending of the signature frame, the node enters the voting state. According to the receiving state of the voting frame on the CAN bus and the status of each node in the data field of the voting frame, after receiving the voting frame of the forward node or the timeout time, the broadcast sends The voting frame of the backward node; if no abnormal state occurs, the node on the CAN bus always works in the voting state; if the isolation frame sent by other nodes is received, the node in the isolation state will be removed from the voting group during voting;

Inquiry state:

After a node has been voted abnormal by the forward node for three consecutive times, it is determined that the node is an abnormal node. The abnormal node and its forward node enter the query state at the same time. The forward node sends a query frame to the backward node, and the backward node After receiving the challenge frame, it returns a challenge response frame. If the backward node returns a challenge response frame, both the backward node and its forward node return to the voting state, and the voting group continues the voting process; if the backward node is questioned three times in a row, no In response, the forward node broadcasts the isolation frame to the CAN bus, isolates the backward node from the voting group, and the backward node enters the isolation state; the forward node returns to the voting state after sending the isolation frame;

Isolation state: Nodes in isolation state cannot send data and cannot participate in voting. They are isolated from other nodes on the bus to avoid further expansion of communication abnormalities. When the isolated node resumes normal communication, it enters the signature state by default.

This embodiment is described with reference to FIG. 2. After the node is powered on or changes from abnormal communication to normal communication, it enters the signature state by default, and sends a signature frame; when the node votes out of the communication state to the node, it enters the voting state, and sends a message to the backward node. Voting frame (including voting normal frame and voting abnormal frame); after the backward node is voted as abnormal for three consecutive times, it enters the challenge state, and the forward node sends a challenge frame to the backward node (the backward node sends a challenge response frame); When the forward node is challenged for three consecutive times and has no response, the forward node sends an isolation frame to isolate the backward node from the voting group, and the backward node enters the isolation state.

In this embodiment, for the method for determining the timeout period, each node dynamically calculates the timeout period according to the node serial number contained in the received communication frame, and the calculation formula is: if the node number > the node number of the sending communication frame, then the node timeout period=( Node number - node number of sending communication frame)*ΔT; if node number ≤ node number of sending communication frame, then node timeout = (total number of nodes + node number - node number of sending communication frame)*ΔT;

As shown in Fig. 1, the node 1 is currently sending the voting frame, then the timeout time of the subsequent response to the node 2 is (2-1)*ΔT, and the timeout time of the node N is (N-1)*ΔT. The first responding node after node N sends is node 1. The ΔT is the set unit timeout time, which is determined according to the total number of nodes on the bus and the working form of the nodes.

In this embodiment, the CAN extended frame is used for communication, and Table 1 is defined as the requirements for filling in the arbitration fields of different communication frames, and the schematic diagram of the definition of the arbitration fields is shown in FIG. 3 . The arbitration field ID28~ID21 is defined as the fault diagnosis frame identification, 8bits, default AAH; ID20~ID17 is the frame type identification bit, 4bits; ID16~ID13 is defined as the sending node identification, 4bits; ID12~ID09 is the backward node identification, filled with The number of the backward node that votes, is challenged, is isolated or needs the first response; ID08~ID05 are the total number of nodes in the voting group, 0001b~1111b respectively indicate that there are 1~15 nodes on the bus, and 0000b indicates that there are 16 nodes on the bus ;ID04~ID00 are reserved bits. As shown in Figure 3. The data field is 8 bytes long, and the definition is shown in Table 2 for the filling description of the data field. Each communication frame contains the voting result of the node to the backward node, and the data frame reception information of other nodes.

Table 1

Table 2

4 to 7, this embodiment is an example of a small satellite voting type communication abnormality diagnosis method described in Embodiment 1: this embodiment uses CAN of five nodes Take the bus network as an example to describe the communication fault diagnosis process in detail:

First, the initial process

1) As shown in Figure 4, after the nodes on the CAN bus are powered on, they are all in the signature state. By default, the signature frame is sent from node 0, and the data field is filled with 0 by default;

2) Other nodes start to send signature frames in turn after receiving the forward node signature frame, and the data field is filled with 0 by default;

3) After all nodes send signature frames, node 0 starts to send voting normal frames. Since no voting normal frames from other nodes are received, the data field status is filled with 0;

4) After receiving the normal voting frame of node 0, node 1 sends the normal voting frame. Since the normal voting frame of node 0 is received, the state of node 0 in the data field of the sent normal voting frame is filled with 0+1=1;

5) Node 2 sends a voting normal frame after receiving the voting normal frame of node 1. The state of node 0 in the voting normal frame of node 1 is 1, and node 2 receives the voting normal frame sent by node 0, so the data field The status of node 0 is filled with 1+1=2; since the voting normal frame of node 1 is received, the status of node 1 in the data domain is filled with 1;

6) After receiving the voting normal frame of node 2, node 3 sends the voting normal frame. In the voting normal frame of node 2, the state of data domain node 0 is 2, the state of data domain node 1 is 1, and node 3 receives the node 0. The voting normal frame sent by node 1, so in the voting normal frame sent, fill in 2+1=3 for the state of node 0 in the data domain, and fill in 1+1=2 for the state of node 1 in the data domain; since the voting of node 2 is received For normal frames, fill in 1 for the status of node 2 in the data field;

7) After node 4 receives the voting normal frame sent by node 3, the first one satisfies the voting conditions and starts to vote on node 0. The state of node 0 in the data domain in the normal voting frame of node 3 is 3, and node 4 The voting normal frame of node 0 is received, and the status of node 0 received by node 4 is 3+1=4. Except for the voted node, all nodes have received the voting normal frame sent by it, so node 4 sends the voting normal frame. , the voting node 0 is in a normal state;

8) Other nodes send voting normal frames in turn, and the communication status to the node after voting;

9) After node 3 sends the voting normal frame, all nodes on the bus have been voted, and all nodes are in a normal state;

10) Nodes on the bus cyclically send voting normal frames in the order of 0->1->2->3->4->0.

2. Voting process for abnormal communication

1) As shown in Figure 5, if node 1 fails, the node fails to send the voting normal frame successfully;

2) Node 2 does not receive the normal voting frame from the forward node, and the timeout time ΔT=10ms. After waiting for 20ms, node 2 sends the normal voting frame independently. Since the normal voting frame from node 1 is not received, the state of node 1 in the data domain is fill in 0;

3) After node 3 receives the voting normal frame of node 2, it sends the voting normal frame. Since the state of node 1 in the data field in the voting normal frame of node 2 is 0, and node 3 has not received the voting normal frame of node 1, the data Fill in 0 for the status of domain node 1;

4) Other nodes send the voting normal frame after receiving the voting normal frame from the forward node;

5) After node 0 receives the normal voting frame sent by the forward node, the status of node 1 in the data domain is 0, and the voting abnormal frame is sent, and the voting node 1 is abnormal;

6) Other nodes continue the voting process, and then communicate the status to the node after voting;

7) If node 0 votes for node 1 to communicate abnormally for three consecutive times, after sending the voting exception frame for the third time, node 0 and node 1 enter the inquiry state.

3. Inquiry Process

1) As shown in Figure 6, node 0 and node 1 are in a challenge state, and node 0 sends a challenge frame to node 1;

2) Node 0 sends a challenge frame for the second time when node 1 has no response and waits for 3ms;

3) When node 1 has no response and waits for 3ms, node 0 sends a challenge frame for the third time;

4) If the challenge response frame is still not received after waiting for 3ms, that is, there is no response after sending the challenge frame 3 times in a row, then node 0 sends an isolation frame to isolate node 1 from the system, so that node 1 is in an isolated state and no longer participates. Bus fault diagnosis process. When other nodes receive the isolation frame, the total number of nodes on the bus is decremented by 1, and node 1 is no longer considered for communication on the bus;

5) After sending the isolation frame, node 0 sends a voting normal frame again to start a new round of voting. At this time, since node 1 has been isolated, the total number of nodes on the bus is 4, and the backward node of node 0 becomes node 2;

6) After node 2 receives the isolation frame, the total number of nodes on the bus is correspondingly changed to 4, the forward node becomes node 0, and the voting normal frame is sent after receiving the voting normal frame of node 0;

7) Other nodes on the bus cyclically send voting normal frames in the order of 0->2->3->4->0.

4. The node returns to normal and re-participates in the voting process

1) As shown in Figure 7, after the communication of node 1 returns to normal, after it sends the voting normal frame to the forward node (node 0), it sends a signature frame and adds 1 to the total number of bus nodes;

2) After node 2 receives the signature frame sent by node 1, it changes the state of node 1 in the data domain in the voting normal frame, indicating that it has received the signature frame sent by node 1;

3) Other nodes change the state of data domain node 1 according to the receiving rules;

4) After node 0 receives the voting normal frame of node 4, voting node 1 is in a normal state, sends a voting normal frame, adds 1 to the total number of nodes, and changes the backward node to 1, and no longer votes on node 2, other nodes After receiving the voting normal frame, cancel the isolation state of node 1;

5) Node 1 completes the voting on Node 2 according to the data receiving state, and sends a voting normal frame;

6) Other nodes change the total number of nodes on the bus to 5, complete the voting on the backward nodes, and send the voting normal frame;

7) The nodes on the bus cyclically send voting normal frames in the order of 0->1->2->3->4->0.

Claims (5)

1. A small satellite voting type communication abnormity diagnosis method is characterized in that a diagnosis mechanism of multi-host combined voting is designed on a CAN bus in a daisy chain topology mode, communication is performed in a CAN bus broadcasting mode, a group of diagnosis broadcast frame protocols are designed, and voting of a single-machine communication state is realized in a time-limited response mode;

the specific diagnosis process is as follows:

setting N nodes on a CAN bus, respectively setting two adjacent nodes as a forward node and a backward node according to the sequence of node numbers from small to large, forming a voting group by all normal working nodes, and sequentially and circularly communicating according to the sequence; n is a positive integer and N is less than or equal to 16; the forward node collecting voting group completes voting on the backward nodes according to the data receiving states of N-1 nodes except the backward nodes;

each node has four working states, namely a signature state, a voting state, an inquiry state and an isolation state;

signature state: after the nodes are initially electrified or normal communication is converted from abnormal communication, the nodes enter a signature state by default, and each node broadcasts and sends a signature frame to a CAN bus after receiving a signature frame, a voting frame or overtime according to the node number of the node, so that the node is represented to be in a normal communication state;

voting state:

after the signature frame is sent, the nodes enter a voting state, and the voting frame of the backward nodes is broadcast and sent after the voting frame of the forward nodes is received or the overtime time is reached according to the receiving state of the voting frame on the CAN bus and the state of each node in the data domain of the voting frame; if no abnormal state occurs, the nodes on the CAN bus always work in a voting state; if isolated frames sent by other nodes are received, eliminating the nodes in an isolated state from a voting group during voting;

a challenge state:

after a certain node is voted as abnormal by a forward node for three times continuously, the node is judged to be an abnormal node, the abnormal node and the forward node enter an inquiry state simultaneously, the forward node sends an inquiry frame to a backward node, the backward node returns an inquiry response frame after receiving the inquiry frame, if the backward node returns the inquiry response frame, the backward node and the forward node both return a voting state, and a voting group continues to carry out a voting process; if the backward node is continuously inquired for three times and has no response, the forward node broadcasts and sends an isolation frame to the CAN bus, the backward node is isolated out of a voting group, and the backward node enters an isolation state; the forward node returns to a voting state after sending the isolation frame;

isolation state:

and when the isolated node recovers normal communication, the isolated node enters a signature state by default.

2. A voting type communication abnormality diagnosis method for minisatellite according to claim 1, wherein the timeout time is calculated by: each node dynamically calculates the overtime time according to the node serial number contained in the received communication frame, and the calculation method of the overtime time is as follows: if the node number is larger than the node number of the sending communication frame, the node overtime time is (the node number-the node number of the sending communication frame) × delta T; and if the node number is not more than the node number of the sending communication frame, the node overtime time is (the total node number + the node number-the node number of the sending communication frame) × Delta T, and the Delta T is the set unit overtime time.

3. A voting type communication abnormality diagnosis method for small satellites according to claim 1, wherein if isolated frames sent by other nodes are received, nodes in an isolated state are rejected from a voting group during voting, and the total number of nodes on a bus is reduced by 1.

4. A voting type communication abnormality diagnosis method for small satellites according to claim 1, wherein when the isolated node recovers normal communication, a signature frame is sent, and after voting that the node is normal through its forward node, 1 is added to the total number of CAN bus nodes.

5. A voting type communication abnormality diagnosis method for small satellite according to claim 2, wherein the communication frame includes information received by the node that transmitted the frame and the result of voting performed by the node that subsequently transmitted the frame or the data frame of the other node.

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