CN115134034B - Cloud edge virtual-real combination simulation time synchronization method and system - Google Patents

Cloud edge virtual-real combination simulation time synchronization method and system Download PDF

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CN115134034B
CN115134034B CN202210788061.3A CN202210788061A CN115134034B CN 115134034 B CN115134034 B CN 115134034B CN 202210788061 A CN202210788061 A CN 202210788061A CN 115134034 B CN115134034 B CN 115134034B
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time
virtual
edge
edge center
synchronization
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CN115134034A (en
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林忠伟
李俊
陈修亮
李修和
王成
沈阳
孙国庆
许国珍
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National University of Defense Technology
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H04J3/0658—Clock or time synchronisation among packet nodes
    • H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
    • H04J3/0667—Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/01—Protocols
    • H04L67/10—Protocols in which an application is distributed across nodes in the network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/28—Timers or timing mechanisms used in protocols
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/0008—Synchronisation information channels, e.g. clock distribution lines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
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Abstract

The application relates to a cloud edge virtual-real combination simulation time synchronization method and system. The method comprises the following steps: calculating the receiving time difference of two adjacent data packets of the time synchronization data packets sent by the edge center at different temperatures, calculating the average value of the receiving time difference, constructing a time error vector according to the average value of the time difference at different working temperatures, utilizing the time error vector, a pre-constructed vandermonde matrix and a parameter vector to establish a time synchronization linear equation set, calculating the time synchronization linear equation set according to a pre-constructed deviation estimation model, correcting the system time of the edge center through the obtained edge center time offset coefficient to obtain the system time after the edge center synchronization, and converting the system time after the edge center synchronization according to the virtual-real time expansion coefficient to obtain the virtual time after the edge center synchronization. By adopting the method, the virtual-real combined simulation time synchronization of the cloud edge end can be realized.

Description

Cloud edge virtual-real combination simulation time synchronization method and system
Technical Field
The application relates to the technical field of data processing, in particular to a cloud edge virtual-real combination simulation time synchronization method and system.
Background
Currently, simulations widely studied and used in academia and industry mainly include two categories: virtual simulation and physical simulation, wherein the virtual simulation mainly generates results by constructing pure digital models related to the physical world and driving the models to interactively run according to a certain sequence, the physical simulation is an entity in the interconnected physical world and generates results by data driving the entity to interactively run, the virtual simulation is used for supporting the virtual modeling, multi-time space, multi-resolution, multi-sample optimizing and variable rate simulation running, and the physical simulation is used for collecting the physical world data, correcting the virtual models in real time and controlling the human/object in a loop. From the practical requirement of simulation application, the virtual-real combined simulation system (VRSS) has the advantages of two simulation forms, is considered as a more ideal simulation form, and can effectively meet the requirements of various simulation applications. Modern simulation (including various training systems) generally needs multiple collaborative simulations, and development of novel computing platforms such as cloud computing, edge computing and various heterogeneous computing terminals brings new opportunities for simulation. Corresponding to a cloud side three-level system structure, establishing global simulation at a cloud side, performing simulation operation of multiple sample variable rates, performing global monitoring and optimizing, and simultaneously receiving a data correction model of an edge center; according to actual needs, the edge center is flexibly opened to report local data, an optimal scheme running at the time can be pulled from the cloud, and meanwhile, local simulation and training of a certain scale can be supported; the Terminal reports data to the Edge center or receives action instructions, etc., thus forming a Cloud-Edge-Terminal (CET) three-level simulation system (CET Architecture, CETA) which is mutually cooperated. The operation of the CETA cloud and the edge center is biased to virtual simulation, and most of the edges are physical simulation, so that VRSS can be operated on a CET three-level platform, and virtual-real combined simulation (VRSS oriented to CET) oriented to a cloud edge architecture is formed.
The time is a core concept of simulation, and the time is mainly used for calibrating the sequence among events, so that cause and effect sequence errors are avoided in the event processing process, and the simulation accuracy is ensured. The VRSS contains both virtual time (generally represented by floating point number and taking the simulation start time as 0 time, mainly sent out by events of the digital model) and wall clock time (i.e. the physical time of event occurrence, mainly sent out by events of the physical model), so that the necessary premise of VRSS correctness is to align the two times. CET is a typical distributed computing platform system, including a cloud center, edge devices and end devices, where each platform within the system has a local system time (the most rapid and efficient source of time), but there is a large deviation between the system time of the cloud center, edge devices and end devices, etc. system platforms due to temperature differences, manufacturing process differences, network delays, etc., that is, the wall clock time within the CET is not uniform. To ensure the correctness of VRSSoCET, the virtual and real times must be aligned on the basis of the clock time in the alignment system.
For aligning wall clock time, the GPS or Beidou system widely used at present has high energy consumption and is greatly influenced by signal intensity, and is not suitable for long-term use of small-sized equipment (such as mobile phones, flat plates, embedded development boards and the like), and accurate time protocols (Precision Time Protocol, PTP) need to iteratively exchange time synchronization messages among the equipment, so that the iterative computation cost is excessive, and the time synchronization cost and delay are high. Two types of algorithms are widely used at present for virtual-to-real time conversion: the method is that a central time service process is arranged in the system to grant virtual starting time for other processes, and then simulation is carried out under the control of a time synchronization protocol, so that the accuracy of the algorithm is obviously greatly influenced by network delay, and the algorithm is not suitable for a distributed system such as CET; the method is to connect virtual and real time systems through a physical bus, infer the sequence of events through mutual exclusivity of physical bus electronic signals, and obviously, the algorithm is not applicable to distributed systems such as CET.
In summary, the existing method does not solve the time synchronization problem of virtual and real combination simulation of the cloud edge end.
Disclosure of Invention
Based on this, it is necessary to provide a cloud edge virtual-real combination simulation time synchronization method, a device, a computer device and a storage medium, which can solve the time synchronization problem of the cloud edge virtual-real combination simulation.
A cloud edge virtual-real combination simulation time synchronization method is applied to a distributed system, and comprises the following steps:
the edge center selects a plurality of different working temperatures, and at each working temperature, more than 4 time synchronization data packets are sent to the cloud center in a fixed period;
the cloud center constructs a record set according to the system time of each received time synchronization data packet, and calculates the receiving time difference of two adjacent data packets in the record set;
calculating the average value of the receiving time difference to obtain the average value of the time differences among all the data packets;
constructing a time error vector according to the average value of time differences at different working temperatures, and constructing a time synchronization linear equation set by using the time error vector, a pre-constructed vandermonde matrix and a parameter vector;
calculating a time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient; the edge center time offset coefficient is a time offset coefficient of the system time of the edge center relative to the system time of the cloud center;
correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization;
and constructing a virtual-real time expansion coefficient by using the time unit of the physical simulation system and the time unit of the virtual simulation system, and converting the system time after edge center synchronization according to the virtual-real time expansion coefficient to obtain the virtual time after edge center synchronization.
In one embodiment, the terminal device selects a plurality of different working temperatures, and sends more than 4 time synchronization data packets to the edge center for time synchronization conversion at each working temperature in a fixed period to obtain an end-to-edge time offset coefficient; the end-to-side time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the edge center;
calculating according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient; the end-to-cloud time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the cloud center;
correcting the system time of the terminal equipment according to the end-to-cloud time offset coefficient to obtain the system time after the synchronization of the terminal equipment;
and constructing a virtual-real time expansion coefficient by using the time unit of the physical simulation system and the time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the synchronized virtual time of the terminal equipment.
In one embodiment, the calculating according to the end-to-edge time offset coefficient and the edge center time offset coefficient to obtain the end-to-cloud time offset coefficient includes:
calculating according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient ofα i Time offset coefficient representing edge center i relative to cloud center, +.>Representing the time offset coefficient of the jth end device of the edge center i relative to the edge center i. In one embodiment, creating a system of time-synchronized linear equations using a time error vector, a pre-constructed vandermonde matrix, and a parameter vector, comprises:
establishing a time synchronization linear equation set as TQ by using a time error vector, a pre-constructed Van der Monte matrix and a parameter vector T ＝E T
Wherein,,η, T (T) and T ideal Respectively representing temperature-sensitive coefficient, real-time working temperature and ideal working temperature of a time component oscillator of the edge center, i represents serial number of the edge center, < >>Representing elements in the parameter vector, T representing the Van der Waals matrix, Q T Representing the parameter vector () T Representing a transpose operation, E representing a temporal error vector.
In one embodiment, calculating the time synchronization linear equation set according to the pre-constructed deviation estimation model to obtain the edge center time offset coefficient includes:
calculating a time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient as
Wherein,,and respectively representing the temperature-sensitive coefficient of the time component oscillator at the center of the edge, the real-time working temperature and the estimated value of the ideal working temperature.
In one embodiment, correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization includes:
correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization asWherein ET is i Representing the system time at the edge center.
In one embodiment, converting the system time after edge center synchronization according to the virtual-to-real time expansion coefficient to obtain the virtual time after edge center synchronization includes:
converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the virtual time after edge center synchronization as
Wherein tdf=u v /U r Representing the expansion coefficient of virtual and real time, U r Representing time units of physical simulation system, U v Representing virtual simulation system time units, st (E i ，rt x ) Indicating any time rt x Edge-to-centerSystem time after step, st (E i ,rt 0 ) Indicating the edge centre instant rt 0 Synchronized system time.
A cloud edge virtual-real combination simulation time synchronization system comprises a cloud center, an edge center and terminal equipment;
the edge center selects a plurality of different working temperatures, and at each working temperature, more than 4 time synchronization data packets are sent to the cloud center in a fixed period;
the cloud center constructs a record set according to the system time of each received time synchronization data packet, and calculates the receiving time difference of two adjacent data packets in the record set;
the cloud center calculates the average value of the receiving time difference to obtain the average value of the time difference among all the data packets; constructing a time error vector according to the average value of time differences at different working temperatures, and constructing a time synchronization linear equation set by using the time error vector, a pre-constructed vandermonde matrix and a parameter vector; calculating a time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient; the edge center time offset coefficient is a time offset coefficient of the system time of the edge center relative to the system time of the cloud center;
the edge center corrects the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center is synchronized; constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization;
the terminal equipment selects a plurality of different working temperatures, and sends more than 4 time synchronization data packets to the edge center at each working temperature in a fixed period to perform time synchronization conversion to obtain an end-to-edge time offset coefficient; the end-to-side time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the edge center;
the terminal equipment calculates according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient; the end-to-cloud time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the cloud center;
correcting the system time of the terminal equipment according to the end-to-cloud time offset coefficient by the terminal equipment to obtain the system time after the synchronization of the terminal equipment; and constructing a virtual-real time expansion coefficient by using the time unit of the physical simulation system and the time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the synchronized virtual time of the terminal equipment.
According to the cloud edge virtual-real combination simulation time synchronization method and system, the system time is used as a time source, the receiving time difference of two adjacent data packets is calculated by using time synchronization data packets sent by an edge center at different temperatures, then the average value of the receiving time difference is calculated, a time error vector is built according to the average value of the time difference at different working temperatures, a time synchronization linear equation set is built by using the time error vector, a pre-built vandermonde matrix and a parameter vector, then the time synchronization linear equation set is calculated according to a pre-built deviation estimation model, an edge center time offset coefficient is obtained, and the system time of the edge center is corrected by the edge center time offset coefficient, so that the system time after edge center synchronization is obtained; and finally, constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, and converting the system time after edge center synchronization according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization, thereby realizing the time synchronization of virtual-real combination simulation of the cloud edge.
Drawings
FIG. 1 is a flow chart of a cloud end virtual-real combination simulation time synchronization method in one embodiment;
fig. 2 is a schematic diagram of a cloud end virtual-real combination simulation time synchronization system in an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
In one embodiment, as shown in fig. 1, a cloud edge virtual-real combination simulation time synchronization method is provided, which includes the following steps:
step 102, selecting a plurality of different working temperatures by the edge center, and sending more than 4 time synchronization data packets to the cloud center at each working temperature in a fixed period.
At present, a time component widely used by electronic equipment is a time component based on an oscillator, which outputs an electronic signal with a certain frequency according to an inherent oscillation frequency and generates a time signal through rectification, generally, the time component manufactured by production can ensure higher time precision under test conditions, but the time precision is obviously influenced by working environment temperature, and when a large number of electronic equipment work at different environment temperatures, the system time can generate larger offset, so the system time cannot be directly used as the wall clock time of a simulation system.
The cloud center, the edge equipment and the tail end equipment all have local system time (the most rapid and efficient time source), but the cloud center has larger deviation among the system time of the edge equipment and the tail end equipment due to temperature difference, manufacturing process difference, network delay and the like, and when virtual and real combination simulation of the cloud edge end is carried out, time synchronization is needed, the edge center is generally provided by a medium-sized and small-sized server, and certain calculation and storage capacity is provided, so that certain-scale simulation operation can be supported. Edge center E i K (k epsilon (3, 20)) different working temperatures { T i I=0, 1, …, k-1}, at the same temperature with a fixed period τ i Transmitting L, L to cloud center>4 time synchronization data packetsThe operating temperature of the oscillator in the center of the edge affects its time accuracy and therefore needs to be transmitted at multiple operating temperaturesThe plurality of time synchronization data packets are used for time synchronization, so that errors are reduced.
Step 104, the cloud center constructs a record set according to the system time of each received time synchronization data packet, and calculates the receiving time difference of two adjacent data packets in the record set; and carrying out average value calculation on the receiving time difference to obtain the average value of the time differences among all the data packets.
The cloud center refers to a large-scale public cloud center such as an Arian cloud, a Temminck cloud and the like, the system time refers to the time acquired by a simulation system from a host operating system, and the system time is the most convenient and energy-saving time source of the distributed platform, so that the application adopts the system time as the time source and provides the system time CT (t) at any physical moment.
The cloud center receives time synchronization data packets sent by the edge center and records the system time of completely receiving each data packet to form a record setAnd then sequentially calculating the receiving time difference of the adjacent two data packetsThen the average value of the time difference is obtained->
And 106, constructing a time error vector according to the average value of the time differences at different working temperatures, and constructing a time synchronization linear equation set by using the time error vector, the pre-constructed vandermonde matrix and the parameter vector.
Respectively obtaining the average value of the time differences at k working temperatures to obtain vectors
Constructing Fan Demeng German matrix as
Further introducing a parameter vector q= [ Q ] m ,m＝0,1,…,k-1]At this time, a time synchronous linear equation set TQ can be established T ＝E T Then there is Q T ＝T -1 E T 。
Step 108, calculating a time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient; the edge center time offset coefficient is a time offset coefficient of the system time of the edge center relative to the system time of the cloud center.
The reason for the deviation of the system time without using the system platform is that the deviation of the system time generated by the oscillator is mainly influenced by the working temperature, so that a deviation estimation model is constructed according to the temperature sensitive coefficient, the real-time working temperature and the ideal working temperature of the oscillator
Where τ is the packet switching period.
When k takes 3 (or selects 3 from a plurality of temperature scenes), T is a 3-order Fan Demeng German square matrix and has data pointsT 0 And 1 are different from each other (here, the temperature values are avoided from being 1 and 0), then T is present in the T inverse matrix -1 I.e. solve the matrix Q T And then developing the constructed deviation estimation model to obtain:
the parameter estimated value in the bias estimation model which can be constructed at the moment is
Substituting the parameter estimation value in the constructed deviation estimation model into the constructed deviation estimation model to obtain the edge equipment E i System time ET on i Time offset coefficient relative to cloud center system time.
Step 110, correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization; and constructing a virtual-real time expansion coefficient by using the time unit of the physical simulation system and the time unit of the virtual simulation system, and converting the system time after edge center synchronization according to the virtual-real time expansion coefficient to obtain the virtual time after edge center synchronization.
The virtual time refers to a data structure used for representing the occurrence time of the simulation event in the simulation system, and is used for calibrating the precedence relationship between the events, and can be any data type which can be compared in size, such as an integer, a floating point number and the like. Correcting the system time of the edge center by calculating the edge center time offset coefficient to obtain the system time after the edge center is synchronized; and then constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, converting the system time after edge center synchronization according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization, realizing the time synchronization of cloud-side virtual-real combination simulation, converting an event sent from a physical model into global virtual time consistent with a cloud-side full system according to the local system time of the event, queuing by taking the virtual time as an event timestamp, and treating the event as a virtual event which cannot be rolled back and withdrawn, thereby ensuring the causal sequence constraint of the event in the cloud-side virtual-real combination simulation and ensuring the accuracy of the simulation.
According to the cloud edge virtual-real combination simulation time synchronization method, the system time is used as a time source, the receiving time difference of two adjacent data packets is calculated by using time synchronization data packets sent by an edge center at different temperatures, then the average value of the receiving time difference is calculated, a time error vector is built according to the average value of the time difference at different working temperatures, a time synchronization linear equation set is built by using the time error vector, a pre-built vandermonde matrix and a parameter vector, then the time synchronization linear equation set is calculated according to a pre-built deviation estimation model, an edge center time offset coefficient is obtained, and the system time of the edge center is corrected by the edge center time offset coefficient, so that the system time after edge center synchronization is obtained; and finally, constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, and converting the system time after edge center synchronization according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization, thereby realizing the time synchronization of virtual-real combination simulation of the cloud edge.
In one embodiment, the terminal device selects a plurality of different working temperatures, and sends more than 4 time synchronization data packets to the edge center for time synchronization conversion at each working temperature in a fixed period to obtain an end-to-edge time offset coefficient; the end-to-side time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the edge center;
calculating according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient; the end-to-cloud time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the cloud center;
correcting the system time of the terminal equipment according to the end-to-cloud time offset coefficient to obtain the system time after the synchronization of the terminal equipment;
and constructing a virtual-real time expansion coefficient by using the time unit of the physical simulation system and the time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the synchronized virtual time of the terminal equipment.
In one embodiment, the calculating according to the end-to-edge time offset coefficient and the edge center time offset coefficient to obtain the end-to-cloud time offset coefficient includes:
calculating according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient ofα i Time offset coefficient representing edge center i relative to cloud center, +.>Representing the time offset coefficient of the jth end device of the edge center i relative to the edge center i.
In a specific embodiment, as shown in fig. 2, the end device generally only needs to synchronize and convert the time of the edge center to which the end device belongs, and when all the end device and the edge center complete the time alignment and conversion process with the cloud center, the system time between any two devices can be converted, and further, the event scheduling can be performed in the whole system.
In one embodiment, creating a system of time-synchronized linear equations using a time error vector, a pre-constructed vandermonde matrix, and a parameter vector, comprises:
establishing a time synchronization linear equation set as TQ by using a time error vector, a pre-constructed Van der Monte matrix and a parameter vector T ＝ T
Wherein,,η, T (T) and T ideal Respectively representing temperature-sensitive coefficient, real-time working temperature and ideal working temperature of a time component oscillator of the edge center, i represents serial number of the edge center, < >>Representing elements in the parameter vector, T representing the Van der Waals matrix, Q T Representing the parameter vector () T Representing a transpose operation, E representing a temporal error vector.
In one embodiment, calculating the time synchronization linear equation set according to the pre-constructed deviation estimation model to obtain the edge center time offset coefficient includes:
calculating a time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient as
Wherein,,and respectively representing the temperature-sensitive coefficient of the time component oscillator at the center of the edge, the real-time working temperature and the estimated value of the ideal working temperature.
In one embodiment, correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization includes:
correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization asWherein ET is i Representing the system time at the edge center.
In a specific embodiment, according toE of cloud center system time relative to edge equipment can also be reversely deduced i Offset.
In one embodiment, converting the system time after edge center synchronization according to the virtual-to-real time expansion coefficient to obtain the virtual time after edge center synchronization includes:
converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the virtual time after edge center synchronization as
Wherein tdf=u v /U r Representing the virtual-real time expansion systemNumber U r Representing time units of physical simulation system, U v Representing virtual simulation system time units, st (E i ,rt x ) Indicating any time rt x System time after edge center synchronization, st (E i ,rt 0 ) Indicating a certain instant rt at the centre of the edge 0 Synchronized system time.
In a specific embodiment, at a certain time rt on the cloud center 0 System time st (C, rt) of (e.g. 2022, 1, 0 minutes, 0 seconds) 0 )＝CT 0 As a simulation start time, it is subordinate to a certain edge center E i At rt 0 The corrected system time of the moment is st (E i ,rt 0 )，rt 0 Corresponding to virtual time vt (C, rt 0 ) Time unit U of physical simulation system is set at time=0 r Virtual simulation system time unit U v Given the virtual-to-real time expansion coefficient tdf=u v /U r Can establish any time rt x Edge device E i Correspondence of system time to virtual time:
events from the mock-up are converted to virtual times according to their local system time and queued with the virtual times as event time stamps, after which they can be treated as a virtual event that is not rollback and not revocable (here it is assumed that the end device does not have the ability to rollback and undo events).
It should be understood that, although the steps in the flowchart of fig. 1 are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in fig. 1 may include multiple sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, nor do the order in which the sub-steps or stages are performed necessarily performed in sequence, but may be performed alternately or alternately with at least a portion of other steps or sub-steps of other steps.
In one embodiment, as shown in fig. 2, a cloud edge virtual-real combination simulation time synchronization system is provided, which includes: cloud center CT, edge center ET, and end device PT, wherein:
the edge center ET selects a plurality of different working temperatures, and at each working temperature, more than 4 time synchronization data packets are sent to the cloud center in a fixed period;
the cloud center CT constructs a record set according to the system time of each received time synchronization data packet, and calculates the receiving time difference of two adjacent data packets in the record set;
the cloud center CT calculates the average value of the receiving time difference to obtain the average value of the time difference among all the data packets; constructing a time error vector according to the average value of time differences at different working temperatures, and constructing a time synchronization linear equation set by using the time error vector, a pre-constructed vandermonde matrix and a parameter vector; calculating a time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient; the edge center time offset coefficient is a time offset coefficient of the system time of the edge center relative to the system time of the cloud center;
the edge center ET corrects the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization; constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization;
the terminal equipment PT selects a plurality of different working temperatures, and at each working temperature, more than 4 time synchronization data packets are sent to the edge center in a fixed period to perform time synchronization conversion, so that an end-to-side time offset coefficient is obtained; the end-to-side time offset coefficient is the time offset coefficient of the system time of the end device relative to the system time of the edge center
The terminal equipment PT calculates according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient; the end-to-cloud time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the cloud center;
correcting the system time of the terminal equipment according to the end-to-cloud time offset coefficient by the terminal equipment PT to obtain the synchronized system time of the terminal equipment; and constructing a virtual-real time expansion coefficient by using the time unit of the physical simulation system and the time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the synchronized virtual time of the terminal equipment.
In the cloud edge virtual-real combination simulation time synchronization system, the application adopts the system time as a time source, the receiving time difference of two adjacent data packets is calculated by using time synchronization data packets sent by an edge center at different temperatures, then the average value of the receiving time difference is calculated, a time error vector is built according to the average value of the time difference at different working temperatures, a time synchronization linear equation set is built by using the time error vector, a pre-built vandermonde matrix and a parameter vector, then the time synchronization linear equation set is calculated according to a pre-built deviation estimation model, an edge center time offset coefficient is obtained, and the system time of the edge center is corrected by the edge center time offset coefficient, so that the system time after the edge center synchronization is obtained; and finally, constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, and converting the system time after edge center synchronization according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization, thereby realizing the time synchronization of virtual-real combination simulation of the cloud edge.
For a specific limitation of the virtual-real combination simulation time synchronization of the cloud edge, reference may be made to the limitation of the virtual-real combination simulation time synchronization method of the cloud edge, which is not described herein. All or part of each module in the cloud edge virtual-real combination simulation time synchronization can be realized by software, hardware and a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
In an embodiment a computer device is provided comprising a memory storing a computer program and a processor implementing the steps of the method of the above embodiments when the computer program is executed.
In one embodiment, a computer storage medium is provided, on which a computer program is stored which, when executed by a processor, implements the steps of the method of the above embodiments.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the various embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims (7)

1. The cloud edge virtual-real combination simulation time synchronization method is characterized by being applied to a distributed system and comprising the following steps of:
the edge center selects a plurality of different working temperatures, and at each working temperature, more than 4 time synchronization data packets are sent to the cloud center in a fixed period;
the cloud center constructs a record set according to the system time of each received time synchronization data packet, and calculates the receiving time difference of two adjacent data packets in the record set;
calculating the average value of the receiving time difference to obtain the average value of the time differences among all the data packets;
constructing a time error vector according to the average value of time differences at different working temperatures, and constructing a time synchronization linear equation set by using the time error vector, a pre-constructed vandermonde matrix and a parameter vector;
calculating the time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient; the edge center time offset coefficient is a time offset coefficient of the system time of the edge center relative to the system time of the cloud center;
correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center synchronization;
constructing a virtual-real time expansion coefficient by using a time unit of a physical simulation system and a time unit of a virtual simulation system, and converting the system time after edge center synchronization according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization;
the terminal equipment selects a plurality of different working temperatures, and sends more than 4 time synchronization data packets to the edge center at each working temperature in a fixed period to perform time synchronization conversion to obtain an end-to-edge time offset coefficient; the end-to-side time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the edge center;
calculating according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient; the end-to-cloud time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the cloud center;
correcting the system time of the terminal equipment according to the end-to-cloud time offset coefficient to obtain the system time after the synchronization of the terminal equipment;
and constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the virtual time after synchronization of the terminal equipment.
2. The method of claim 1, wherein calculating from the end-to-edge time offset coefficient and the edge center time offset coefficient results in an end-to-cloud time offset coefficient, comprising:
calculating according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient as followsWherein alpha is i Time offset coefficient representing edge center i relative to cloud center, +.>Representing the time offset coefficient of the jth end device of the edge center i relative to the edge center i.
3. The method according to any one of claims 1 to 2, wherein creating a system of time-synchronized linear equations using the time error vector, a pre-constructed vandermonde matrix and a parameter vector, comprises:
using the time error vector, the pre-constructed Van der Monte matrix and the parameter vector to establish a time synchronous linear equation set as TQ T ＝E T
Wherein,,η, T (T) and T ideal Respectively representing temperature-sensitive coefficient, real-time working temperature and ideal working temperature of a time component oscillator of the edge center, i represents serial number of the edge center, < >>Representing elements in the parameter vector, T representing the Van der Waals matrix, Q T Representing the parameter vector () T Representing a transpose operation, E representing a temporal error vector.
4. A method according to claim 3, wherein calculating the set of time-synchronized linear equations based on a pre-constructed bias estimation model yields an edge-centered time offset coefficient, comprising:
calculating the time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient as follows
Wherein,,and respectively representing the temperature-sensitive coefficient of the time component oscillator at the center of the edge, the real-time working temperature and the estimated value of the ideal working temperature.
5. The method of claim 4, wherein correcting the system time of the edge center based on the edge center time offset coefficient results in a system time after edge center synchronization, comprising:
correcting the system time of the edge center according to the edge center time offset coefficient to obtain the system time after edge center synchronization as followsWherein ET is i Representing the system time at the edge center.
6. A method according to claim 3, wherein converting the edge-centric synchronized system time according to the virtual-real time expansion coefficient to obtain an edge-centric synchronized virtual time comprises:
converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the virtual time after edge center synchronization as
Wherein tdf=u v /U r Representing the expansion coefficient of virtual and real time, U r Representing time units of physical simulation system, U v Representing virtual simulation system time units, st (E i ,rt x ) Indicating any time rt x System time after edge center synchronization, st (E i ,rt 0 ) Indicating the edge centre instant rt 0 Synchronized system time.
7. The cloud edge virtual-real combination simulation time synchronization system is characterized by comprising a cloud center, an edge center and terminal equipment;
the edge center selects a plurality of different working temperatures, and at each working temperature, more than 4 time synchronization data packets are sent to the cloud center in a fixed period;
the cloud center constructs a record set according to the system time of each received time synchronization data packet, and calculates the receiving time difference of two adjacent data packets in the record set;
the cloud center calculates the average value of the receiving time difference to obtain the average value of the time difference among all the data packets; constructing a time error vector according to the average value of time differences at different working temperatures, and constructing a time synchronization linear equation set by using the time error vector, a pre-constructed vandermonde matrix and a parameter vector; calculating the time synchronization linear equation set according to a pre-constructed deviation estimation model to obtain an edge center time offset coefficient; the edge center time offset coefficient is a time offset coefficient of the system time of the edge center relative to the system time of the cloud center;
the edge center corrects the system time of the edge center according to the edge center time offset coefficient to obtain the system time after the edge center is synchronized; constructing a virtual-real time expansion coefficient by using a time unit of a physical simulation system and a time unit of a virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain virtual time after edge center synchronization;
the terminal equipment selects a plurality of different working temperatures, and sends more than 4 time synchronization data packets to the edge center at each working temperature in a fixed period to perform time synchronization conversion to obtain an end-to-edge time offset coefficient; the end-to-side time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the edge center;
the terminal equipment calculates according to the end-to-side time offset coefficient and the edge center time offset coefficient to obtain an end-to-cloud time offset coefficient; the end-to-cloud time offset coefficient is a time offset coefficient of the system time of the end device relative to the system time of the cloud center;
the terminal equipment corrects the system time of the terminal equipment according to the end-to-cloud time offset coefficient to obtain the system time after the terminal equipment is synchronized; and constructing a virtual-real time expansion coefficient by using a time unit of the physical simulation system and a time unit of the virtual simulation system, and converting the synchronized system time according to the virtual-real time expansion coefficient to obtain the virtual time after synchronization of the terminal equipment.
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