CN101995872B - Compensation method of time variable network time delay of network cascade control system - Google Patents

Abstract

The invention provides a compensation method of time variable network time delay of a network cascade control system, belonging to the technical field of network control systems. In the invention, a network data transmission process among all forward network path nodes and feedback network path nodes in a real network cascade control system is used for replacing a network time delay compensation model to avoid measuring, observing, estimating or identifying the network data transmission time variable time delay among the nodes and avoid synchronizing node clock signals. By adopting the method, the influence of the time variable network time delay on the system stability can be reduced, and the system control property and quality can be improved. The invention is suitable for the dynamic compensation and control of the time variable network time delay of all forward and feedback paths when the network is also in the network cascade control system under the conditions that a main controlled object mathematical model is given or uncertain, an auxiliary controlled object mathematical model is given, and the network time delay can be longer than several and even dozens of sampling periods.

Description

A kind of compensation method of time variable network time delay of network cascade control system

Technical field

The present invention relates to a kind of compensation method of time variable network time delay of network cascade control system, belong to the network control system technical field.

Background technology

Network control system (Networked control systems, NCS) refer to that communication passes through the closed-loop control system of a real-time network, compare with traditional point-to-point control, network control system has can realize resource sharing, operated from a distance, the advantages such as the low and easy maintenance of cost, large scale industry process control and small-sized local system have been widely used in (such as spacecraft, boats and ships and novel high-performance automobile etc.). still, because the network bandwidth is limited, the transmission of information can produce network delay inevitably, the existence of time delay is so that poor system performance, when serious even have influence on Systems balanth. simultaneously, since the time variation of network delay, the in the extreme difficulty so that the analysis and design of network control system becomes.

At present, research about network control system mainly is for single-circuit control system both at home and abroad, constant at network delay respectively, in time, become or at random, network delay is less than a sampling period or greater than a sampling period, single bag transmission or many bag transmission, have or not under the various conditions such as data-bag lost, it is carried out modeling and stability analysis, but rarely have paper that the network cascade control system is studied. control loop is called network cascade control system (NCCS) by the cascade control system of real-time network closure, is applicable to the typical structure block diagram of network cascade control system of the present invention as shown in Figure 1.

Because the network cascade control system is the network control system of closed loop more than, analysis on network delay impact is more complex more than single-circuit network control system with the research of system performance. and the inner looping network delay will have a strong impact on rapidity and the antijamming capability of inner looping network control system, simultaneously also will be with the external loop network delay to the stability of whole network cascade control system with control quality and have a negative impact.

Difficult point for network delay research is:

(1) because network delay is relevant with factors such as network topology structure, communication protocol, offered load, the network bandwidth and data package sizes. to the network delay greater than several and even dozens of sampling period, set up accurately predict, the mathematical model of estimation or identification, almost be impossible at present.

(2) occur in the backward network delay in node transmitting network data process of previous node, in previous node, no matter adopt which kind of prediction or method of estimation, all can not know in advance the exact value of the network delay that produces thereafter in advance. time delay causes system performance to descend even causes system unstable, brings difficulty also for simultaneously analysis and the design of control system.

(3) will satisfy in the network cascade control system, all node clock signal Complete Synchronizations in different distributions place are unpractical.

For network be present in simultaneously in all forward directions and the feedback network the network cascade control system as shown in Figure 2, its input R (s) with output Y ₁(s) closed loop between is transmitted letter

$\frac{Y_1\left(s\right)}{R\left(s\right)}=\frac{C_1\left(s\right)e^{-{\mathrm{\τ}}_{1}s}{C}_2\left(s\right)e^{-{\mathrm{\τ}}_{3}s}{G}_2\left(s\right)G_1\left(s\right)}{1+C_1\left(s\right)e^{-{\mathrm{\τ}}_{1}s}{C}_2\left(s\right)e^{-{\mathrm{\τ}}_{3}s}{G}_2\left(s\right)G_1\left(s\right)e^{-{\mathrm{\τ}}_{2}s}+C_2\left(s\right)e^{-{\mathrm{\τ}}_{3}s}{G}_2\left(s\right)e^{-{\mathrm{\τ}}_{4}s}}---\left(1\right)$

In the formula: C ₁(s) be master controller, C ₂(s) be submaster controller; G ₁(s) be main controlled device, G ₂(s) be secondary controlled device; τ ₁Expression is transferred to the time variation network delay that the submaster controller node produces with network data from the master controller node; τ ₂Expression is transferred to the time variation network delay that the master controller node produces with network data from main transmitter node; τ ₃Expression is transferred to the time variation network delay that the submaster controller node produces with network data from secondary transmitter node; τ ₄Expression is transferred to the time variation network delay that the actuator node produces with network data from the submaster controller node;

Owing to comprise network delay τ in the denominator of the closed loop transfer function, shown in the equation (1) ₁And τ ₂, τ ₃And τ ₄Exponential term

With

With

The existence of time delay will worsen the control performance quality of system, even cause system's loss of stability, when serious system be broken down.

Reduce time delay to the sex key of system stability, just be to realize with time variation network delay τ ₁And τ ₂, τ ₃And τ ₄Exponential term

With

With

From the denominator of equation (1), remove, namely realize not comprising in system's closed loop secular equation the exponential term of all-network time delay, yet and then realization is to the compensation of network delay., realize the compensation to network delay, at first must know the size of network delay. at present, the method that usually adopts both at home and abroad is by to network delay τ ₁And τ ₂, τ ₃And τ ₄Measurement, come delay compensation τ ₁And τ ₂, τ ₃And τ ₄Impact on system stability. still, because to network delay τ ₁And τ ₂, τ ₃And τ ₄Measurement accuracy need to satisfy the synchronous requirement of node clock signal, if adopt hardware to realize the node clock signal Complete Synchronization, then need larger economic input; If adopt software position signal, when then transmitting between node owing to correction signal, may meet with the impact of network delay, if be difficult to realize the nodal clock Complete Synchronization. adopt network delay is estimated, observation, the method of identification or prediction obtains the size of network delay, then at first must know the accurate probability distribution of network delay, or mathematical model accurately, but because the size of network delay and concrete procotol, the factors such as offered load size and network topology structure are relevant, to the estimation of network delay, observation, all may there be deviation in identification or prediction.

Therefore, how to exempt the requirement synchronous to node clock signal, how to exempt estimation, observation, identification or prediction to network delay between the node, can obtain again simultaneously between the node accurately time delay value, and then realize compensating action to time variation network delay in all path networks of network cascade control system, having become in the network cascade control system needs one of key issue that solves.

Summary of the invention

In order to solve the problems of the technologies described above, the invention provides a kind of compensation method of time variable network time delay of network cascade control system.

Purpose of the present invention:

In the network cascade control system, the difficult problem of network delay " indeterminacy ", the present invention proposes a kind of release to main transmitter, master controller, secondary transmitter and the synchronous requirement of actuator node clock signal, while is also exempted the delay compensation method to measurement, estimation or the identification of time variation network delay in the network cascade control system, realizes the network delay segmentation in all forward directions and the feedback network, compensates and control in real time, online and dynamically.

The method that the present invention adopts is:

The first step: adopt main transmitter node to replace the compensation model of network delay therebetween to the live network data transmission procedure between the master controller node, the system that structurally realizes does not comprise the compensation model of network delay therebetween. no matter to the network path the master controller node how complicated and uncertain is arranged from main transmitter node, also no matter include therebetween what routers or (with) intermediate link, the network delay that information flow experiences is exactly real network delay in the control procedure, has just realized the compensate function to its time delay in the information stream transmission process.

Second step: adopt secondary transmitter node to replace the compensation model of network delay therebetween to the live network data transmission procedure between the submaster controller node, the system that structurally realizes does not comprise the compensation model of network delay therebetween. no matter to the network path the submaster controller node how complicated and uncertain is arranged from secondary transmitter node, also no matter include therebetween what routers or (with) intermediate link, the network delay that information flow experiences is exactly real network delay in the control procedure, has just realized the compensate function to its time delay in the information stream transmission process.

The 3rd step: adopt the master controller node to replace the compensation model of network delay therebetween to the live network data transmission procedure between the submaster controller node, the system that structurally realizes does not comprise the compensation model of network delay therebetween. no matter to the network path the submaster controller node how complicated and uncertain is arranged from the master controller node, also no matter include therebetween what routers or (with) intermediate link, the network delay that information flow experiences is exactly real network delay in the control procedure, has just realized the compensate function to its time delay in the information stream transmission process.

The 4th step: adopt the submaster controller node to replace the compensation model of network delay therebetween to the live network data transmission procedure between the actuator node, the system that structurally realizes does not comprise the compensation model of network delay therebetween, no matter to the network path the actuator node how complicated and uncertain is arranged from the submaster controller node, also no matter include therebetween what routers or (with) intermediate link, the network delay that information flow experiences is exactly real network delay in the control procedure, has just realized the compensate function to its time delay in the information stream transmission process.

The 5th step: for network cascade control system shown in Figure 2, implement the network delay collocation structure of the inventive method as shown in Figure 3.

In Fig. 3, from input R (s) and the output Y of system ₁(s) closed loop transfer function, between is

$\frac{Y_1\left(s\right)}{R\left(s\right)}=\frac{e^{-{\mathrm{\τ}}_{1}s}{e}^{-{\mathrm{\τ}}_{3}s}{C}_1\left(s\right)C_2\left(s\right)G_2\left(s\right)G_1\left(s\right)}{1+e^{-{\mathrm{\τ}}_{3}s}{C}_1\left(s\right)C_2\left(s\right)[G_2\left(s\right)-G_{2m}\left(s\right)]e^{-{\mathrm{\τ}}_{4}s}+C_1\left(s\right)C_2\left(s\right)G_2\left(s\right)G_1\left(s\right)+C_2\left(s\right)G_2\left(s\right)}---\left(2\right)$

When secondary controlled device prediction model equals its true model, i.e. G _2m(s)=G ₂(s) time, formula (2) but abbreviation be

$\frac{Y_1\left(s\right)}{R\left(s\right)}=\frac{e^{-{\mathrm{\τ}}_{1}s}{e}^{-{\mathrm{\τ}}_{3}s}{C}_1\left(s\right)C_2\left(s\right)G_2\left(s\right)G_1\left(s\right)}{1+C_2\left(s\right)G_2\left(s\right)+C_1\left(s\right)C_2\left(s\right)G_2\left(s\right)G_1\left(s\right)}---\left(3\right)$

In the closed loop transfer function, denominator of network cascade control system, do not comprise network delay τ shown in the formula (3) ₁And τ ₂, τ ₃And τ ₄Exponential term, namely realized closed loop secular equation 1+C ₂(s) G ₂(s)+C ₁(s) C ₂(s) G ₂(s) G ₁(s)=0 do not comprise the exponential term of network delay in, thereby eliminated the impact of network delay on system stability, improved the control performance quality of system, realized the compensate function to the time variation network delay.

The scope of application of the present invention:

The present invention is applicable in the network cascade control system, main controlled device mathematical model is known or be uncertain of, secondary controlled device mathematical model is known, network delay can be greater than several and even dozens of sampling period, and network is present in dynamic compensation and the control of the time variation network delay in external loop and all paths of inner looping.

The invention is characterized in that the method may further comprise the steps:

1, is sampled cycle h when main transmitter node ₁During triggering, will adopt mode A to carry out work;

2, when main transmitter node with main controlled device G ₁(s) output signal Y ₁When (s) transmitting to the master controller node by the external feedback network path, will adopt mode B to carry out work;

3, be sampled cycle h when secondary transmitter node ₂During triggering, will adopt mode C to carry out work;

4, when secondary transmitter node with secondary controlled device G ₂(s) model error signal w ₂When (s) transmitting to the submaster controller node by the internal feedback network path, will adopt mode D to carry out work;

5, when the master controller node by signal Y ₁When (s) triggering, will adopt mode E to carry out work;

6, when the master controller node by outer feedforward network path with error signal e ₁When (s) transmitting to the submaster controller node, will adopt mode F to carry out work;

7, when the submaster controller node by signal w ₂(s) or (with) signal e ₁When (s) triggering, will adopt mode G to carry out work;

8, when the submaster controller node by interior feedforward network path with signal e ₂When (s) transmitting to the actuator node, will adopt mode H to carry out work;

9, when the actuator node by signal e ₂When (s) triggering, will adopt mode I to carry out work.

The step of mode A comprises:

A1: main transmitter node works in the time type of drive, and it triggers the sampling period is h ₁

A2: after main transmitter node is triggered, to main controlled device G ₁(s) output signal Y ₁(s) sample.

The step of mode B comprises:

B1: main transmitter node is with signal Y ₁(s), transmit to the master controller node by the external feedback network path.

The step of mode C comprises:

C1: secondary transmitter node works in the time type of drive, and it triggers the sampling period is h ₂

C2: after secondary transmitter node is triggered, to secondary controlled device G ₂(s) output signal Y ₂(s) and the prediction model G of secondary controlled device _2m(s) output signal y _2m(s) sample;

C3: to Y ₂(s) and y _2m(s) implement additive operation, obtain model error signal w ₂(s).

The step of mode D comprises:

D1: secondary transmitter node is with model error signal w ₂(s), transmit to the submaster controller node by the internal feedback network path.

The step of mode E comprises:

E1: the master controller node works in event driven manner, and by the signal Y from the external feedback network path ₁(s) trigger;

E2: with the given signal R of system (s) and Y ₁(s) add and subtract mutually, obtain external loop systematic error signal e ₁(s).

The step of mode F comprises:

F1: the master controller node is with error signal e ₁(s), transmit to the submaster controller node by outer feedforward network path.

The step of mode G comprises:

G1: the submaster controller node works in event driven manner, and by the signal w from the internal feedback network path ₂(s) or (with) from the signal e of outer feedforward network path ₁(s) trigger;

G2: with e ₁(s) with signal w ₂(s) subtract each other, obtain the inner looping error signal e ₂(s).

The step of mode H comprises:

H ₁: the submaster controller node is with error signal e ₂(s), transmit to the actuator node by interior feedforward network path.

The step of mode I comprises:

I1: the actuator node works in event driven manner;

I2: the actuator node is by error signal e ₂(s) trigger;

I3: with e ₂(s) and Y ₁(s) subtract each other, obtain error signal e ₃(s);

I4: to e ₃(s) implement main control algorithm C ₁(s), controlled signal u ₁(s);

I5: with u ₁(s) and Y ₂(s) subtract each other, obtain error signal e ₄(s);

I6: with e ₄(s) act on sub-control algorithm C ₂(s), controlled signal u ₂(s);

I7: with u ₂(s) as driving signal, to secondary controlled device G ₂(s) implement control; Thereby change G ₂(s) state, and then change G ₁(s) state is realized G ₁(s) and G ₂(s) control action; Finish simultaneously G _2m(s) discreet value y _2m(s) calculate.

10, delay compensation method of the present invention, it is characterized in that system comprises the unit such as main transmitter node, secondary transmitter node, master controller node, submaster controller node, actuator node, main controlled device and secondary controlled device, each unit carries out work according to working method and the function set separately.

11, delay compensation method of the present invention it is characterized in that replacing network delay compensation model therebetween with the data transmission procedure of all real external loop network paths, thereby the system that structurally realizes does not comprise the compensation model of network delay therebetween.

12, delay compensation method of the present invention it is characterized in that replacing it to ask the network delay compensation model with the data transmission procedure of all real inner looping network paths, thereby the system that structurally realizes does not comprise the compensation model of network delay therebetween.

13, delay compensation method of the present invention is characterized in that from measurement, observation, estimation or the identification of structure release to network delay between all nodes of network cascade control system.

14, delay compensation method of the present invention is characterized in that exempting the synchronous requirement of all node clock signals of network cascade control system from structure.

15, delay compensation method of the present invention is characterized in that realizing from structure the enforcement and concrete control strategy C of method for compensating network delay ₁(s) and C ₂(s) selection is irrelevant.

16, delay compensation method of the present invention is characterized in that realizing that from structure the enforcement of method for compensating network delay is irrelevant with the selection of concrete network communication protocol.

17, delay compensation method of the present invention is characterized in that as secondary controlled device G ₂(s) with its prediction model G _2mWhen (s) equating, can realize the full remuneration to network cascade control system external loop and inner looping network path time variation network delay, improve the control performance quality of system.

18, delay compensation method of the present invention, what it is characterized in that adopting is the compensation method that " soft " changes the control system structure, need not increases any hardware device again, and the software resource that utilizes existing network cascade control system intelligent node to carry just is enough to realize its compensate function.

19, delay compensation method of the present invention, the mode A of it is characterized in that are applicable to main transmitter node periodic sampling and signal are processed.

20, delay compensation method of the present invention, the mode B of it is characterized in that are applicable to main transmitter node transmitting network data.

21, delay compensation method of the present invention, the mode C of it is characterized in that are applicable to secondary transmitter node periodic sampling and signal are processed.

22, delay compensation method of the present invention, the mode D of it is characterized in that are applicable to secondary transmitter node transmitting network data.

23, delay compensation method of the present invention, the mode E of it is characterized in that are applicable to the master controller node signal are processed.

24, delay compensation method of the present invention, the mode F of it is characterized in that are applicable to master controller node transmitting network data.

25, delay compensation method of the present invention, the mode G of it is characterized in that are applicable to the submaster controller node signal are processed.

26, delay compensation method of the present invention, the mode H of it is characterized in that are applicable to submaster controller node transmitting network data.

27, delay compensation method of the present invention, the mode I of it is characterized in that are applicable to the actuator node to secondary controlled device G ₂(s) implement control, and signal processed.

The present invention has following advantage:

1, owing to exempted the inner-outer loop from structure, measurement, observation, estimation or the identification of all-network path time variation network delay, also exempted simultaneously the synchronous requirement of node clock signal, and then avoided the inaccurate evaluated error that causes of time delay estimation model, avoided the required waste that expends the node storage resources of time-delay identification, also avoided simultaneously because the compensating error that " the empty sampling " that time delay causes or " many samplings " bring.

2, owing to realized with the selection of concrete network communication protocol irrelevantly from structure, thereby both be applicable to adopt the network cascade control system of wired network protocol, also be applicable to the network cascade control system of wireless network protocol; Both be applicable to the deterministic network agreement, also be applicable to the procotol of time variation.

3, owing to realized with the selection of concrete network communication protocol irrelevant from structure, thereby both be applicable to heterogeneous network cascade control system based on wired network protocol, also be applicable to the heterogeneous network cascade control system based on wireless network protocol, also be applicable to simultaneously the delay compensation of the network cascade control system of heterogeneous (such as wired and wireless mixing).

4, owing to realized with the selection of the control strategy of concrete master (pair) controller irrelevant from structure, thereby both can be used for adopting the conventional network cascade control system of controlling, the network cascade control system that also can be used for adopting Based Intelligent Control or adopt the complex control strategy.

5, because the present invention adopts is the compensation method that " soft " changes the control system structure, thereby in its implementation procedure, need not to increase again any hardware device, the software resource that utilizes existing network cascade control system intelligent node to carry, just be enough to realize its compensate function, thereby can save hardware investment, be easy to be extended and applied.

Description of drawings

Fig. 1 is that network is present in the network cascade control system block scheme in all paths of inner-outer loop.

Fig. 2 is that network is present in the network cascade control system structural drawing in all paths of inner-outer loop.

Fig. 3 is in the network cascade control system all-network path of the present invention, time variation method for compensating network delay structural drawing.

In the block scheme of Fig. 1, system is by input signal (R), main controlled device (G ₁), main transmitter (S ₁), external loop feedback network path, master controller (C ₁), external loop feedforward network path; Secondary transmitter (S ₂), inner looping feedback network path, submaster controller (C ₂), inner looping feedforward network path, actuator (A), secondary controlled device (G ₂) etc. the unit form.

Main transmitter (S ₁) node adopts the time type of drive to carry out work, the triggering cycle is h ₁, to main controlled device (G ₁) the implementation cycle sampling.

Master controller (C ₁) node adopts event driven manner to carry out work, by main transmitter (S ₁) output signal of node triggers by the external feedback network path.

Submaster controller (C ₂) node adopts event driven manner to carry out work, by secondary transmitter (S ₂) output signal by inner looping feedback network path, or (with) by master controller (C ₁) output signal of node triggers by external loop feedforward network path.

Secondary transmitter (S ₂) node adopts the time type of drive to carry out work, the triggering cycle is h ₂, to secondary controlled device (G ₂) the implementation cycle sampling.

Actuator (A) node adopts event driven manner to carry out work, by submaster controller (C ₂) node triggers by the control signal of inner looping feedforward network path, thereby driving topworks changes secondary controlled device (G ₂) state, and then change main controlled device (G ₁) state.

Main transmitter (the S of system among Fig. 1 ₁) node, secondary transmitter (S ₂) node, master controller (C ₁) node, submaster controller (C ₂) node, and actuator (A) node all is intelligent node, not only possess storage calculation function and communication function, and possess software configuration and control function, these nodes comprise now the hardware such as intelligent node common in the industrial field bus control system (FCS) of widespread use and the Distributed Control System (DCS) (DCS) or smart machine.

In the system of Fig. 2, the time variation network delay in the data transmission procedure has significant impact for Systems balanth and control performance quality. and the data transmission of network cascade control system is experiencing from main transmitter node and is being transferred to the time variation network delay τ that the master controller node produces through the external feedback network path ₂, be transferred to the time variation network delay τ that the submaster controller node produces from the master controller node through outer feedforward network path ₁, be transferred to the time variation network delay τ that the actuator node produces from the submaster controller node through interior feedforward network path ₃, and be transferred to the time variation network delay τ that the submaster controller node produces from secondary transmitter node through the internal feedback network path ₄Impact. time delay is relevant with the concrete factors such as procotol, offered load size and network topology structure, yet for the measurement of network delay or estimate or observation or identification have become the crucial precondition that realizes its compensation., the distributivity of each node by network connection is so that each node in the network cascade control system is difficult to satisfy the requirement of clock signal synchronization. simultaneously, because the time variation of network delay and sudden will accomplish that each step can both Accurate Prediction be impossible.

In the system of Fig. 3, neither comprise from main transmitter node and be transferred to network delay prediction model between the master controller node through the external feedback network path, also do not comprise from the master controller node and be transferred to network delay prediction model between the submaster controller node through outer feedforward network path; Do not comprise simultaneously from the submaster controller node yet and be transferred to network delay prediction model between the actuator node through interior feedforward network path, and be transferred to network delay prediction model between the submaster controller node from secondary transmitter node through the internal feedback network path. and then exempted time variation network delay τ ₁And τ ₂, τ ₃And τ ₄Measurement, estimation, observation or identification, also exempted (main transmitter, secondary transmitter, master controller, submaster controller, actuator) the synchronous requirement of node clock signal simultaneously. when major-minor controlled device prediction model model true with it, and submaster controller and prediction model thereof be when equating, can realize the output signal Y from the input signal R (s) of system to system ₁(s) in the closed loop transfer function,, with network delay τ ₁And τ ₂, τ ₃And τ ₄Exponential term

With

With

From denominator, eliminate, namely realize not comprising in the closed loop secular equation network delay τ ₁And τ ₂, τ ₃And τ ₄Exponential term, thereby reduced the impact of time delay on system stability, improved the control performance quality of system, realize compensation and control to the time variation network delay.

Embodiment

The below will by describing exemplary embodiment of the present invention in detail with reference to accompanying drawing 3, make clearer above-mentioned and other feature and advantage of the present invention of those of ordinary skill in the art.

The implementation step is as described below:

The first step: work in the main transmitter node of time type of drive to main controlled device G ₁(s) output signal Y ₁(s) (sampling period is h to carry out periodic sampling ₁);

Second step: main transmitter node is with Y ₁(s) be transferred to the master controller node by external loop feedback network path;

The 3rd step: work in the master controller node of event driven manner, by signal Y ₁(s) trigger; With the given signal R of system (s) and Y ₁(s) add and subtract mutually, obtain error signal e ₁(s); And with e ₁(s) be transferred to the submaster controller node by external loop feedforward network path;

The 4th step: work in the secondary transmitter node of time type of drive to secondary controlled device G ₂(s) output signal Y ₂(s) and its prediction model G _2m(s) output signal y _2m(s) (sampling period is h to carry out periodic sampling ₂), and to Y ₂(s) and y _2m(s) implement additive operation, obtain model error signal w ₂(s); And with w ₂(s) be transferred to the submaster controller node by inner looping feedback network path;

The 5th step: work in the submaster controller node of event driven manner, by signal e ₁(s) or (with) w ₂(s) trigger; With e ₁(s) and w ₂(s) subtract each other, obtain error signal e ₂(s); With e ₂(s) transmit to the actuator node by inner looping feedforward network path;

The 6th step: work in the actuator node of event driven manner, by e ₂(s) trigger; With e ₂(s) and Y ₁(s) subtract each other, obtain error signal e ₃(s); To e ₃(s) implement control algolithm C ₁(s), it is output as u ₁(s); With u ₁(s) and Y ₂(s) subtract each other, obtain error signal e ₄(s); To e ₄(s) implement control algolithm C ₂(s), it is output as u ₂(s); With u ₂(s) drive topworks, thereby change secondary controlled device G ₂(s) state, and then change main controlled device G ₁(s) state; Finish simultaneously G _2m(s) discreet value y _2m(s) calculate;

The 7th step: return the first step.

The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

The content that is not described in detail in this instructions belongs to the known prior art of this area professional and technical personnel.

Claims (8)

1. the compensation method of a time variable network time delay of network cascade control system is characterized in that the method may further comprise the steps:

(1). when main transmitter node is sampled cycle h ₁During triggering, will adopt mode A to carry out work;

(2). when main transmitter node with main controlled device G ₁(s) output signal Y ₁When (s) transmitting to the master controller node by the external feedback network path, will adopt mode B to carry out work;

(3). when secondary transmitter node is sampled cycle h ₂During triggering, will adopt mode C to carry out work;

(4). when secondary transmitter node with secondary controlled device G ₂(s) model error signal w ₂When (s) transmitting to the submaster controller node by the internal feedback network path, will adopt mode D to carry out work;

(5). when the master controller node by signal Y ₁When (s) triggering, will adopt mode E to carry out work;

(6). when the master controller node by outer feedforward network path with error signal e ₁When (s) transmitting to the submaster controller node, will adopt mode F to carry out work;

(7). when the submaster controller node by signal w ₂(s) or/and signal e ₁When (s) triggering, will adopt mode G to carry out work;

(8). when the submaster controller node passes through interior feedforward network path with signal e ₂When (s) transmitting to the actuator node, will adopt mode H to carry out work;

(9). when the actuator node by signal e ₂When (s) triggering, will adopt mode I to carry out work;

The step of described mode A comprises:

A1: main transmitter node works in the time type of drive, and it triggers the sampling period is h ₁

A2: after main transmitter node is triggered, to main controlled device G ₁(s) output signal Y ₁(s) sample;

The step of described mode B comprises:

B1: main transmitter node is with signal Y ₁(s), transmit to the master controller node by the external feedback network path;

The step of described mode C comprises:

C1: secondary transmitter node works in the time type of drive, and it triggers the sampling period is h ₂

C2: after secondary transmitter node is triggered, to secondary controlled device G ₂(s) output signal Y ₂(s) and secondary controlled device G ₂(s) prediction model G _2m(s) output signal y _2m(s) sample;

C3: to Y ₂(s) and y _2m(s) implement additive operation, obtain model error signal w ₂(s);

The step of described mode D comprises:

D1: secondary transmitter node is with model error signal w ₂(s), transmit to the submaster controller node by the internal feedback network path;

The step of described mode E comprises:

E1: the master controller node works in event driven manner, and by the signal Y from the external feedback network path ₁(s) trigger;

E2: with the given signal R of system (s) and Y ₁(s) add and subtract mutually, obtain external loop systematic error signal e ₁(s);

The step of described mode F comprises:

F1: the master controller node is with error signal e ₁(s), transmit to the submaster controller node by outer feedforward network path;

The step of described mode G comprises:

G1: the submaster controller node works in event driven manner, and by the signal w from the internal feedback network path ₂(s) or/and from the signal e of outer feedforward network path ₁(s) trigger;

G2: with e ₁(s) with signal w ₂(s) subtract each other, obtain the inner looping error signal e ₂(s);

The step of described mode H comprises:

H1: the submaster controller node is with error signal e ₂(s), transmit to the actuator node by interior feedforward network path;

The step of described mode I comprises:

I1: the actuator node works in event driven manner;

I2: the actuator node is by error signal e ₂(s) trigger;

I3: with e ₂(s) and Y ₁(s) subtract each other, obtain error signal e ₃(s);

I4: to e ₃(s) alms giver's control algolithm C ₁(s), controlled signal is u ₁(s);

I5: with u ₁(s) and Y ₂(s) subtract each other, obtain error signal e ₄(s);

I6: with e ₄(s) act on sub-control algorithm C ₂(s), controlled signal is u ₂(s);

I7: with u ₂(s) as driving signal, to secondary controlled device G ₂(s) implement control, thereby change G ₂(s) state, and then change G ₁(s) state is realized G ₁(s) and G ₂(s) control action; Finish simultaneously G _2m(s) discreet value y _2m(s) calculate.

2. method according to claim 1, it is characterized in that system comprises main transmitter node, secondary transmitter node, master controller node, submaster controller node, actuator node, main controlled device and secondary controlled device unit, each unit carries out work according to the working method of setting separately.

3. method according to claim 1 is characterized in that replacing network delay compensation model therebetween with the data transmission procedure of all real external loop network paths; Data transmission procedure with all real inner looping network paths replaces network delay compensation model therebetween, thereby the system that structurally realizes does not comprise the compensation model of network delay.

4. method according to claim 1 is characterized in that from measurement, observation, estimation or the identification of structure release to network delay between the all-network node; The requirement that release is synchronous to the all-network node clock signal.

5. method according to claim 1 is characterized in that realizing from structure the enforcement and concrete control strategy C of method for compensating network delay ₁(s) and C ₂(s) selection is irrelevant, and is irrelevant with the selection of concrete network communication protocol.

6. method according to claim 1 is characterized in that as secondary controlled device G ₂(s) with its prediction model G _2mWhen (s) equating, can realize the full remuneration to network cascade control system external loop and inner looping network path time variation network delay, improve the control performance quality of system.

7. method according to claim 1, what it is characterized in that adopting is the compensation method that " software " changes the control system structure, need not increases any hardware device again, and the software resource that utilizes existing network cascade control system intelligent node to carry just is enough to realize its compensate function.

8. method according to claim 1, the mode A of it is characterized in that is applicable to main transmitter node periodic sampling and signal is processed; Mode B is applicable to main transmitter node transmitting network data; Mode C is applicable to secondary transmitter node periodic sampling and signal is processed; Mode D is applicable to secondary transmitter node transmitting network data; Mode E is applicable to the master controller node signal is processed; Mode F is applicable to master controller node transmitting network data; Mode G is applicable to the submaster controller node signal is processed; Mode H is applicable to submaster controller node transmitting network data; Mode I is applicable to the actuator node to secondary controlled device G ₂(s) implement control, and signal is processed.

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