EP0940794B1 - Method and device for controlling means of influencing traffic according to the traffic - Google Patents

Abstract

The method involves detecting occupation of measurement cross-sections (6,9) around the management systems (1) and passing these to a controller (3) which derives control parameters for operating the management systems. Condition equations (B1-B3) are stored in a data base (15) associated with a control program. Rules (R1-R4) stored in the data base have three possible rule values per condition equation corresp. to true, false or any and resulting in the selection of an action (A1-A4). Parameter values are compared with threshold values according to the condition equations and the results stored. Truth values are compared with rule values and an action performed if all truth values corresp. to all rule values of an individual rule corresp. to this action.

Description

The invention relates to a method and an apparatus for the traffic-dependent control of means for influencing traffic according to the preamble of the claim 1.

Traffic-dependent traffic influencing takes place nowadays for example via traffic signal systems, variable message signs, changeable parking space information signs or radio announcements. The traffic-dependent data are over Traffic detectors such as induction loops, radar or infrared detectors won.

For example, in traffic signal systems as a means to influence their phase sequences or signal sequences determined by predetermined signal programs. The signal programs are depending on the chosen control method variable. So with traffic-dependent control procedures for example the duration of the individual phases, the order of the individual phases and the number of different Phases (if required) in the signal program changed. With time-dependent control procedures are set at fixed times of the day (e.g. in commuter traffic) different signal programs and thus different phase sequences switched.

For the selection of the signal program or for the selection of the phase duration, the sequence of phases or the number of phases traffic-related parameters are evaluated, which with Help the traffic detectors be determined. in case of a Signal programs with fixed times become the parameters the design processing implemented off-line. In case of a Signal program adaptation or signal program formation are the Parameters processed continuously, with the possibility a changing influence between traffic flow and Signal control. The current signal programs are included according to a given control logic based on each updated parameters calculated and evaluated online. With the help of traffic detectors are in the spatial environment the traffic signal system detects occupancy values, from which parameters of the traffic flow are derived. The waiting time of the vehicles, for example, serves as parameters in front of the traffic signal system, the traffic jam length in front of the Traffic signal system, the traffic volume, i.e. Vehicles per Cross section, the driving speed, a registration (Request) by pedestrians, cyclists and / or vehicles, the occupancy rate, the traffic density, the occupancy rate and the load quotient. With a traffic-dependent signal program selection the processed parameters of the Traffic flow in the control logic for the selection of the signal programs with condition equations and threshold values connected.

From the guidelines for traffic light systems ((RiLSA) - traffic light systems for road traffic - 1992 edition from the Research Society for Roads and Traffic, Working group traffic management and traffic safety, Pages 46 to 47 and Appendix D, Pages 90 to 110) known how control logic with the help of flowcharts being represented. The ones for the traffic-dependent Control of appropriate phases and phase sequences of the traffic signal system represented in a phase sequence plan. The Changes between the phases are precisely defined in the phase transition and presented clearly. A flow chart contains the logical and temporal conditions for the duration of the phases and for switching the phase transitions and thus represents the sequence of traffic-dependent control completely. Logical conditions apply to the Linking the parameters of the traffic flow, and temporal Conditions give the time frame of the program sequences such as minimum and maximum release times a signal group with free circulation time. It should be for all signal programs shown only a single flow chart become. This only flow chart is increasing The complexity of the control logic is becoming increasingly confusing and a transfer of those prescribed in the flow chart Conditions in a traffic description, that interpret a control unit of a traffic signal system can, is becoming increasingly difficult.

It is therefore an object of the invention, a method and a Device for the traffic-dependent control of means for Specify traffic control, which with little effort are adaptable to new traffic conditions and a simple implementation in a traffic description allow.

The object is achieved by a method of the beginning mentioned type with the characterizing features of the claim 1 solved.

The condition equations are stored in a common database file as well as actions that take place within a given Transition of a momentary state within the framework in a better adapted to the current traffic flow updated state to run and rules that the Link the equations of conditions and the actions, stored. By saving them together in a given database format results in both clear presentation as well as a common format for different changes between states.

In a preferred embodiment of the method according to claim 2 several database files are linked together, to handle complex processes flexibly.

According to claim 3, it is advantageously provided that fixed control hierarchies through predefined processing sequences built from different database files become.

The embodiment according to claim 4 is particularly flexible, according to which the control hierarchies can be changed by within of the database files referenced to database files that do not follow directly in the processing order.

The method can advantageously be modified in such a way Traffic conditions that are only caused by an outside of the given adjustment and / or selection of the Control program can be taken into account, thereby adapt that according to claim 5, the condition equations that Rules and / or the actions of the database files changed and saved.

That becomes particularly adaptable to traffic conditions Method according to claim 6, characterized in that within the Actions calculations are performed based on their results in subsequent database files of a processing order Reference is made.

For traffic signal systems as a means of influencing traffic is in an advantageous manner according to claim 7 current signal sequence (current signal program) as current status by another signal sequence (further signal program) replaced as an updated state.

For traffic management systems as a means of influencing traffic is advantageously according to claim 8 the current tax strategy as the current state through a further control strategy replaced as an updated state.

The structure common to all database files according to claim 9 allows implementation in the database file described determination of the current control program through an algorithm common to all database files.

According to claim 10 is a link associated with the actions provided that after the execution of the action refers to another database file to be more advantageous Way by linking database files flexible to use for different traffic processes Get device.

In the advantageous embodiment according to claim 11 in the database files regardless of the actions performed a link to other database files contain, with which a fixed processing hierarchy of the database files is achieved with each other.

By composing condition equations through logical Links from individual conditions according to claim 12 and their logical combination according to claim 13 can handle complex control conditions in a clear, flexible manner be summarized.

For traffic signal systems as a means of influencing traffic is in an advantageous manner according to claim 14 current signal sequence as current status by another Signal sequence replaced as an updated state.

For traffic management systems as a means of influencing traffic is advantageously according to claim 15 the current tax strategy as the current state through a further control strategy replaced as an updated state.

Figur 1 schematisch den Aufbau einer Verkehrssignalanlage mit Verkehrsdetektoren,

Figur 2 einen schematischen Ablaufplan, wie er im Stand der Technik für die Steuerungslogik benutzt wird,

Figur 3 schematisch den Aufbau einer erfindungsgemäßen Datenbankdatei mit Bedingungsgleichungen, Regeln und Aktionen und

Figur 4 schematisch eine Bearbeitungsreihenfolge aus mehreren Datenbankdateien.

The invention is explained in more detail with reference to exemplary embodiments shown in the drawing. Show

FIG. 1 shows schematically the structure of a traffic signal system with traffic detectors,

FIG. 2 shows a schematic flow chart as used for the control logic in the prior art,

Figure 3 shows schematically the structure of a database file according to the invention with condition equations, rules and actions and

Figure 4 schematically shows a processing sequence from several database files.

In Figure 1 is a traffic signal system 1 as an example of a means of influencing traffic, the procedure is also for variable message signs, parking space information signs or to determine redirection measures or automatic radio announcements suitable as well Change from current to further control strategies in traffic management systems.

In traffic signal system 1, two light signal generators 2 controlled via a control unit 3, the cable connections are laid within a whip mast 4, the at the same time as a fastening device for the light signal transmitter 2 serves. With the traffic lights 2 the traffic on a first lane 5 (for example into the city) regulated by a median 7 from a second Lane 8 in the opposite direction of travel (for example out of town). Two traffic detectors 10, for example Inductive loops, take occupancy values from Vehicles in a first measurement cross section 6 on the first Lane 5 and in a second measurement cross section 9 of the second Lane 7 on, transfer them to the control unit 3, in the from this parameters of the traffic flow in the first lane 5 and the second lane 8 can be determined. With help of the determined parameters are the currently switched Signal sequences (current signal program, current status) within of the control unit 3 based on the current traffic flow evaluated and by means of a control program in the control unit 3 may become one for the current traffic flow more suitable further signal sequence (further signal program, updated state) with which the traffic signal system 1 is then operated to a to achieve improved traffic flow. In traffic management systems are used as a means of influencing traffic current control strategies as current status through others Control strategies replaced for the current traffic situation are more appropriate.

In Figure 2 is a conventional flow diagram for the transition a phase 1 into a phase 2 and from phase 2 into a Phase 3 shown, with the vehicles in phase 2 the first lane 5 receive an enable signal. The phase transition PÜ 1,2 from phase 1 to phase 2 lasts 15 s, as shown in an action element 11. While phase 2 becomes the time t that has passed since the phase transition Phase 2 has passed, measured and with the shortest amount of time T1 compared to phase 2 as in a decision element 12 is shown for temporal conditions. As long as the temporal condition equation that the elapsed Time t is greater than the shortest time period T1 Truth value "false" or "no N" is given in one Time loop 14 waited. Only when the condition equation that the elapsed time t is greater than the shortest Time period T1 is given the truth value "true" or "yes J", the process continues. For a needs-based Adjustment of the release time in phase 2 is done in a logical condition equation B checked in this example, whether the time gap between two consecutive Vehicles that are detected by the vehicle sensor 10 are larger as a certain predetermined time, for example 2.5 s is. This logical condition equation B1 is shown schematically in represented a decision element 13 for logical conditions. This logical condition equation receives the truth value "true J" then becomes due to the resulting low traffic density the transition PÜ 2.3 from Phase 2 carried out in a phase 3, the transition being 10 s lasts. The logical condition equation B1 receives the truth value "false N", then it is checked whether the elapsed Time t has already increased since the phase transition to phase 2 than the longest period of time T2 of phase 2. Receives this second temporal condition equation the truth value "true J ", the phase transition PÜ 2,3 from phase 2 also becomes Phase 3 initiated. Receives this second temporal condition equation the truth value "false N", then in one another time loop in a next time step initially the logical condition equation B1 evaluated again. For more complex traffic signal systems than in this example described, the flowchart quickly becomes confusing, complicated to change and is difficult automatic to implement in a traffic description, which is used in the control program of control unit 3 can be.

Analogous to the described transition between two phases also transitions between different signal programs in Dependency of the parameters of the traffic flow shown.

For the description of the solution according to the invention, FIG. 3 assumes that a separate signal program is available for five different traffic situations. There are a first situation S1: little traffic, a second situation S2: day traffic, a third situation S3: peak traffic in the city, a fourth situation S4: peak traffic out of town, a fifth situation S5: peak traffic balanced. Individual conditions are used to describe the traffic flow, which relate determined parameters to predefined threshold values. The individual conditions in this example are a first individual condition b1, which means that the traffic volume in the first measurement cross-section 6 is greater than a threshold value of 800 vehicles per hour, a second individual condition b2, which means that the speed in the first measurement cross-section 6 is less than the threshold value is 30 km / h, a third individual condition b3, which states that the traffic volume in the second measurement cross-section 6 is greater than 800 vehicles per hour, and the one individual condition which states that the speed in this second measurement cross-section 8 is less than 30 km / h. If the first and second individual conditions b1, b2 for the first measurement cross section 6 are met, this corresponds to a peak traffic towards the city, which is described by the second condition equation B2. Correspondingly, when the third and fourth individual conditions b3, b4 are met for the second measuring cross-section 9, there is peak traffic out of town, which is described in the third condition equation B3 by an AND operation of the third and fourth individual conditions b3, b4 , The first condition equation B1 describes a balanced peak traffic, which is characterized in that all four individual conditions are met. The condition equations are stored in a first field of a database file 15 as a decision table, which in this example is based on the currently activated third situation S3. The possible actions for the signal program selection are stored in a second field of the database file 15. In Figure 3, there is a first action A1, in which the fifth situation S5 (balanced peak traffic) is switched, a second action A2, in which the selected signal program for the third situation S3: peak traffic is maintained in the city, a third Action A3, in which the fourth situation S4 (peak traffic out of town) is switched and a fourth action in which the second situation S2 (day traffic) is switched. Actions A1, A2, A3, A4 are selected with the aid of rules R1..R4 stored in a third field in database file 15. The rules R1 to R4 consist of rule values and action notes. In each rule, a condition value is assigned to each condition, which indicates whether the condition has to assume the truth value "true J", the truth value "false N" or any truth value "-", so that the action corresponding to the action note is carried out. FIG. 3 shows that in the first rule R1 the first condition equation B1 must receive the truth value "true J", the truth values of the other two condition equations B2, B3 are not taken into account, and that the action instruction X then refers to the first action A1 with which the balanced peak traffic is switched. The second rule describes that in the event that the first condition equation B1 has the truth value "false N", the second condition equation B2 the truth value "true J" and the third condition equation B3 has an arbitrary truth value, the action instruction X for the second action A2 indicates in which the signal program for the city-centered peak traffic remains switched. The third rule R3, with its action note X, indicates the third action A3, in which a switch is made to the peak traffic directed out of the city if the first and the second condition equations B1, B2 have the truth value "false N" and the third condition equation B3 the truth value " true J ". The fourth rule R4 shows an action instruction X for the fourth action A4, in which the switch is made to the second situation S2, which is carried out when all the condition equations B1, B2, B3 receive the truth value "false N". A linkage action V is stored in a fourth field, which contains further steps to be carried out after the action performed. In this example, the processing is terminated by a termination notice E (Exit).

FIG. 4 shows how linking actions V, after completing actions A1 ... A4, a modular compilation achieved by several database files D1 ... D4 becomes. First of all, there is a predefined processing sequence 20 defines in which the individual database files D1 ... D4 in a fixed order as a control hierarchy to be brought. First, a third database file is created D3, then a second database file D2, then a first database file D1 and finally a fourth Database file 4 edited. The linking actions V in the individual database files D1 ... D4 also allow to change the fixed processing order 20. For example, there is one in the third database file D3 Possibility to jump directly to the fourth database file D4, shown, and in the second database file D2 the termination program E makes the control program direct after processing the second database file D2 ended. in the Normally, the database files D1 ... D4, as indicated by the link action 21 to the address of the subsequent one Table is indicated, processed in the processing order 20.

For an adaptation to traffic conditions which have been changed in such a way that they can no longer be controlled within the predetermined frame with the aid of the further signal sequence, the conditions, the rules, the actions, the linkage actions or the processing sequences must be adapted in the database files 15. As indicated in FIG. 3, individual conditions b1, b2, b3, b4 can be linked to condition equations by Boolean operators. Calculations can also be carried out within the actions, which are used in later database files 15 of a processing sequence 20. Due to the identical structure of various database files 15, an algorithm common to all database files 15 can also be specified, with which the contents of the database files 15 are implemented in a traffic-technical description for the control unit 3.
The method according to the invention can be transferred analogously to traffic management systems in which, based on occupancy values, current control strategies are replaced by further control strategies, which are then implemented by diversion measures, changed displays of variable message signs or parking space information signs or by radio announcements.

Claims (15)

1. Method for the traffic-dependent control of means for influencing (1) traffic having traffic detectors (10) which detect occupation values in measurement cross sections (6, 9) in the spatial surroundings of the means for influencing (1) traffic, having a control device (3) to which the occupation values are transferred and which determines, from the transferred occupation values, characteristic variables of the traffic sequence - conditioned by means of a control program - for an instantaneous state of the means for influencing (1) traffic, compares these conditioned characteristic variables with predefined threshold values according to predefined condition equations (B1, B2, B3) and determines therefrom a state which has been updated in comparison with the instantaneous state within a predefined framework, with which characteristic variables the means for influencing (1) traffic then continues to be operated, characterized in that the condition equations (B1, B2, B3) are stored in a database file (15) which is assigned to the control program and is embodied as a decision table, in that in addition actions (A1, A2, A3, A4) which define steps from the instantaneous state to the updated state are stored in the database file (15), in that in addition rules (R1, R2, R3, R4) which each contain a number of rule values corresponding to the number of condition equations, as well as an action reference (X), are stored in the database file (15), one of three possible rule values being assigned to each condition equation (B1, B2, B3) in each rule (R1, R2, R3, R4), said possible rule values indicating whether the respective condition equation has to assume a true (J) truth value, a false (N) truth value or any desired truth value so that the action (A1, A2, A3, A4) to which the action reference (x) of the respective rule (R1, R2, R3, R4) refers is carried out, in that the conditioned characteristic variables are compared with the predefined threshold values according to the condition equations (B1, B2, B3) of the database file (15) and the truth value of the respective condition equation (B1, B2, B3) is stored as a result of the comparison, in that the truth values are compared with the rule values, and in that, when the truth values correspond to all the rule values of an individual rule (R1, R2, R3, R4), the respective action (A1, A2, A3, A4) to which the action reference (x) of this individual rule (R1, R2, R3, R4) refers is carried out.
2. Method for the traffic-dependent control of means for influencing (1) traffic according to Claim 1, characterized in that the updated state is determined in such a way that the actions (A1, A2, A3, A4) comprise logic linking actions (E) which refer to addresses of further database files (15), as a result of which the database files (15) are logically linked to one another in a modular fashion.
3. Method for the traffic-dependent control of means for influencing (1) traffic according to Claim 2, characterized in that a plurality of database files (15) are logically linked in a predefined processing sequence (20) by means of the logic linking actions (E), as a result of which a control hierarchy in which the plurality of database files (15) are successively evaluated is built up.
4. Method for the traffic-dependent control of means for influencing (1) traffic according to Claim 3, characterized in that by means of these logic linking actions (E) database files (15) which do not directly follow in the processing sequence (20) are also referred to so that the control hierarchy can thus be varied.
5. Method for the traffic-dependent control of means for influencing (1) traffic according to one of Claims 3 or 4, characterized in that the actions (A1, A2, A3, A4) comprise calculation rules, in that, when the actions (A1, A2, A3, A4) are carried out, results are determined and stored by means of the calculation rules, and in that these results are taken into account in the condition equations (B1, B2, B3) of database files (15) which follow in the control hierarchy.
6. Method for the traffic-dependent control of means for influencing (1) traffic according to one of Claims 1 to 5, characterized in that, when traffic sequences which differ from the predefined framework in such a way that no updated state is provided occur, the condition equations (B1, B2, B3), the rules (R1, R2, R3, R4) and/or the actions (A1, A2, A3, A4) of the database files (15) are changed and the changed condition equations (B1, B2, B3), rules (R1, R2, R3, R4) and actions (A1, A2, A3, A4) are stored.
7. Method for the traffic-dependent control of means for influencing (1) traffic according to one of Claims 1 to 6, characterized in that, when there is a traffic signal system (1) as means for influencing the traffic, an instantaneous signal program as the instantaneous state is replaced by a further signal program as the updated state.
8. Method for the traffic-dependent control of means for influencing (1) traffic according to one of Claims 1 to 6, characterized in that when there is a traffic management system (1) as means for influencing the traffic an instantaneous control strategy as the instantaneous state is replaced by a further control strategy as the updated state.
9. Device for the traffic-dependent control of means for influencing (1) traffic having traffic detectors (10) which detect occupation values in measurement cross sections (6, 9) in the spatial surroundings of the means for influencing (1) traffic, having a control device (3) to which the occupation values are transferred and which determines, from the transferred occupation values, characteristic variables of the traffic sequence - conditioned by means of a control program - for an instantaneous state of the means for influencing (1) traffic, compares these conditioned characteristic variables with predefined threshold values according to predefined condition equations (B1, B2, B3) and determines therefrom a state which has been updated in comparison with the instantaneous state within a predefined framework, with which characteristic variables the means for influencing (1) traffic then continues to be operated, characterized in that the control program comprises database files (15) which are embodied as decision tables and have an identical structure composed of fields, in that the condition equations (B1, B2, B3) are stored in a first field, in that actions (A1, A2, A3, A4) which define steps from the instantaneous state to the updated state are stored in a second field, in that rules (R1, R2, R3, R4) which each contain a number of rule values corresponding to the number of condition equations, as well as an action reference (X) are stored in a third field, one of three possible rule values being assigned to each condition equation (B1, B2, B3) in each rule (R1, R2, R3, R4), said rule values indicating whether the respective condition equation has to assume a true (J) truth value, a false (N) truth value or any desired truth value so that the action (A1, A2, A3, A4) to which the action reference (X) of the respective rule (R1, R2, R3, R4) refers is carried out.
10. Device for the traffic-dependent control of means for influencing (1) traffic according to Claim 9, characterized in that a logic linking action in the form of an address of a further database file (15) which is to be processed subsequently is stored in the second field in addition to the respective action.
11. Device for the traffic-dependent control of means for influencing (1) traffic according to one of Claims 9 or 10, characterized in that a logic linking action in the form of an address of a further database file (15) which is to be processed subsequently is stored in a fourth field.
12. Device for the traffic-dependent control of means for influencing (1) traffic according to one of Claims 9 to 11, characterized in that the condition equations (B1, B2, B3) are composed of individual conditions (b1, b2).
13. Device for the traffic-dependent control of means for influencing (1) traffic according to Claim 12, characterized in that the individual conditions (b1, b2) in the condition equations (B1, B2, B3) are logically linked to one another.
14. Device for the traffic-dependent control of means for influencing traffic according to one of Claims 9 to 13, characterized in that the means for influencing traffic are embodied as traffic signal systems (1) whose instantaneous signal sequence is replaced as an instantaneous state by a further signal sequence as an updated state.
15. Device for the traffic-dependent control of means for influencing traffic according to one of Claims 9 to 13, characterized in that the means for influencing traffic are embodied as traffic management systems whose instantaneous control strategy is replaced as an instantaneous state by a further control strategy as an updated state.

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