[0147] Example two
[0148] A method of using the intelligent traffic control system based on the wireless Mesh ad hoc network described in the first embodiment for intelligent traffic control, which is a method that combines ZigBee short-range wireless communication technology and intelligent network technology to control each node in the system The traffic flow parameter collection and traffic signal control equipment is connected to the Mesh self-organizing network through Zigbee wireless communication, and the control target area is predefined according to the GPS node positioning information and the road network topology (this area can be planned as points and lines according to actual needs. , Planar) and neighboring associated nodes in accordance with the BNNC traffic control protocol-that is, the traffic control node based on the neighboring negotiation mechanism of the traffic control protocol, real-time exchange of traffic flow parameters, signal control parameters and negotiate the control of each traffic signal control node In decision-making, the TSCA signal control negotiation mechanism of the system adopts a combination of explicit coordination based on game theory and implicit coordination based on knowledge rules; ZigBee regional base stations are based on the BDAT communication protocol stack, and the GPRS/CDMA data transmission terminal combines the Traffic detection and signal control data are uploaded to the traffic control center; the traffic control center downloads some adjustment and optimization parameters or compulsory instructions to each control node to participate in specific intersection signal timing decisions when necessary intervention; system traffic signal coordination control station The required synchronization clock is calibrated independently by the GPS timing module of each node.
[0149] The intelligent traffic control system based on the wireless Mesh ad hoc network of the present invention is used in the method for intelligent traffic control. The control decision of each traffic signal control node includes: the intersection traffic light timing scheme, based on the traffic flow exchanged by neighboring associated nodes in real time Parameters, semaphore control parameters and stored road network topology, historical traffic flow parameters and traffic control data, as well as the central control center's command weighted to make new signal control parameters.
[0150] The method for intelligent traffic control of the intelligent traffic control system based on the wireless Mesh ad hoc network of the present invention includes two components, one is the "neighboring negotiation node search and control node related sub-road network topology establishment algorithm" which establishes the basis of communication between nodes. The other is the "small area self-coordinating traffic signal control algorithm" based on the "neighboring negotiation node search and control node related sub-road network topology establishment algorithm".
[0151] (1) The basic steps of the algorithm of "neighboring negotiation node search and control node related sub-road network topology establishment":
[0152] M1: After the system nodes are powered on, self-check and initialize, and check whether they can work normally, if they can't work normally, go to M2, otherwise go to M3;
[0153] M2: Check if you can work offline, if not, go to M21, if you can work independently offline, go to M22;
[0154] M21: End of node work;
[0155] M22: Work independently according to experience knowledge or pre-stored timing plan;
[0156] M3: Join the Zigbee network to obtain the Zigbee short address, and request a copy of the regional road network topology data from neighboring nodes, including the GPS position, serial number, right of way level, turn and the association between all nodes and branches or sections of the area Parameters, go to M4;
[0157] M4: Receive local node positioning information from GPS satellite positioning module;
[0158] M5: Retrieve the location of the node in the road network topology map according to the positioning information. If the node cannot match any node in the road network topology map, switch to M22 to work independently according to experience knowledge or pre-stored timing scheme, otherwise switch to M6 to continue carried out;
[0159] M51: During the normal operation of the system, if the node receives the control center road network topology update notification, the node workflow unconditionally jumps to M5 and re-executes in sequence;
[0160] M6: Generate the inactive sub-road network topology map associated with this node, find the nodes and branches associated with this node according to the definition of the regional road network topology map, and trim the regional road network topology into the inactive sub-road network associated with this node The topology diagram of the sub-road network is transferred to M7 for execution;
[0161] M61: During the normal operation of the system, if the short address of the node ZigBee network reorganization changes, the node workflow unconditionally jumps to M6 and re-executes in sequence;
[0162] M7: Check whether the associated sub-road network topology exists. If it does not exist, switch to M22 to work independently based on empirical knowledge or pre-stored timing plan. If it exists, create 6 parallel subtasks S1, S2, S3, S4, S5 and S6 to execute simultaneously;
[0163] ①The execution steps of subtask S1:
[0164] S11: Listen to whether the associated node responds to the broadcast datagram that the node is working online, if it does, enter S12, if it does not return to S11, continue to listen;
[0165] S12: Extract the associated node information from the received datagram and verify the existence of the node in the associated sub-road network topology, if it exists, go to S13, otherwise return to S11 to continue the interception;
[0166] S13: After activating the status of the associated node and branch corresponding to the sub-road network, return to S11 to continue listening;
[0167] ②The execution steps of subtask S2:
[0168] S21: Listen to the online working broadcast datagram of the road network node, and transfer to S22 if received, otherwise return to S21 to continue the interception;
[0169] S22: Extract the node information from the received datagram and retrieve the node in the associated sub-road network topology, if it exists, go to S23, otherwise return to S21 to continue the interception;
[0170] S23: Determine whether the node status has been activated, if it is not activated, go to S241, if it is activated, go to S242;
[0171] S241: Activate the corresponding node and branch in the sub-road network topology, and record the corresponding parameters such as its communication address, and at the same time send an online response with the source address of the datagram as the target address and transfer it back to S21 for execution;
[0172] S242: Check whether the relevant parameters of the node need to be updated, if it needs to be updated, switch to S25, otherwise switch to S21;
[0173] S25: Update the relevant parameters of the corresponding node and branch in the sub-road network topology and then return to S21 for execution;
[0174] ③The execution steps of subtask S3:
[0175] S31: Search and check the status of each associated node in the sub-road network topology diagram of the node one by one;
[0176] S32: If an associated node is not in the active state, switch to S31 to continue the judgment of the next node, otherwise switch to S33;
[0177] S33: Regularly send an online heartbeat packet representing the normal operation of the node to the active state node, so that it can maintain its associated sub-road network topology online node list, and provide a basis for normal traffic signal negotiation and control between nodes, and then return to S31 to continue The judgment of the next node;
[0178] ④ Steps for subtask S4:
[0179] S41: Detect the receiving status of the heartbeat packets of each associated node in the sub-road network topology map, and determine whether there is an associated node stoppage, that is, the offline communication connection is lost, and if so, go to S42;
[0180] S42: Change the status of the node and related branches in the sub-road network topology to invalid, and switch to S41 to continue;
[0181] ⑤ Execution steps of subtask S5:
[0182] S51: Listen to whether there is a neighboring node requesting this node to copy the topological graph data of the road network in this area, if yes, go to S52;
[0183] S52: Determine whether there is a copy of the regional road network topology map at this node, and continue without going to S51, if there is, go to S53;
[0184] S53: Send the relevant data of the regional road network topology to the requester, then transfer to S51 to continue;
[0185] ⑥ Steps for subtask S6:
[0186] S61: Search for the status of each associated node in the sub-road network topology map, and go to S62;
[0187] S62: If an inactive node is found, go to S63, if not, go to S61;
[0188] S63: Regularly broadcast to announce that the node has been online and work, then transfer to S61 to continue execution.
[0189] (2) The basic steps of "Small Area Self-coordination Traffic Signal Control Algorithm" are:
[0190] The control algorithm is divided into 4 parallel subtasks T1, T2, T3 and T4, which are executed simultaneously:
[0191] ① The execution steps of subtask T1:
[0192] T11: Listen to the working datagram sent by the associated node of the sub-road network and save it;
[0193] T12: Check whether the current traffic signal control cycle of this node is about to end, if not, turn to T11, otherwise turn to T13;
[0194] T13: Obtain the traffic detection data of this node, as well as the traffic flow parameters of the associated nodes in the sub-road network topology and the corresponding timing plan. According to the control model algorithm and the needs of "point, line, surface" control, determine whether it needs to be adjacent to the relevant The node performs coordinated control. If it is not needed, it will go to T14 directly. If it needs coordinated control, it will go to T131 for execution;
[0195] T131: Send a negotiation request and execute the corresponding coordination process within the specified time, agree on the control parameters, and then transfer to T14;
[0196] T14: Substitute the corresponding parameters determined in the above steps into the control model to obtain the current signal control cycle data of this node, and set and execute various timing parameters of the signal control machine of this node, and go to T15;
[0197] T15: Read the local synchronization clock, send the signal timing plan datagram with the synchronization time stamp of the node to each active node of the sub-road network and the regional base station, and then transfer back to T11 to continue execution;
[0198] ② The execution steps of subtask T2:
[0199] T21: Judge whether the calibration period of the local synchronization clock has arrived, if so, turn to T22;
[0200] T22: Read the GPS module timing information to synchronize the local clock, go to T21 to continue execution;
[0201] ③ The execution steps of subtask T3:
[0202] T31: Determine whether the local traffic flow detection data sending cycle has come, if it has come, turn to T32;
[0203] T32: Read the local synchronous clock, and send traffic flow data of this node to each active node of the sub-road network and regional base stations; go to T31 to continue execution;
[0204] ④ Execution steps of subtask T4:
[0205] T41: Listen to whether there is an associated node requesting a coordinated control message, and if so, forward to T42;
[0206] T42: Decide whether to accept the coordinated control request according to the current control strategy and traffic conditions of the node. If rejected, transfer to T421 for execution, and if agreed, transfer to T43 for execution;
[0207] T421: Send a refusing coordination message to the requesting party, transfer to T41 to continue;
[0208] T43: Check whether there is a suitable knowledge rule, if there is, transfer to T431 for execution, if not, transfer to T432 for execution;
[0209] T431: Select rules and determine the corresponding control strategy according to the rules, then transfer to T44;
[0210] T432: Seek the optimal solution for coordination, determine the control strategy of both parties, and transfer to T44;
[0211] T44: Draw various coordinated control parameters into the control decision-making link, and then return to T41 to continue execution.
[0212] In the method for intelligent traffic control of the intelligent traffic control system based on the wireless Mesh ad hoc network of the present invention, the TSCA signal control negotiation mechanism of the system is composed of the TSCA communication protocol stack, and the ZigBee regional base station is based on the BDAT communication protocol stack. The composition and the data unit of the traffic control protocol-BNNC traffic control protocol based on the neighbor negotiation mechanism of the traffic control node, namely: the ZigBee network layer data frame format has been described in detail in the first embodiment, and will not be repeated here.