JPH064107A - System identifying device - Google Patents

Abstract

PURPOSE:To provide the system identifying device which can be improved in identification precision. CONSTITUTION:Operation signals 7 are inputted to plural input terminals of a controlled system 2 respectively to obtain output signals 8 from plural output terminals respectively, and the device is equipped with a switch 4 which switches and inputs one of those output signals 8 and an identifying calculation means which identifies and calculates part of the input/output relation of the controlled system 2 on the basis of the one output signal and a branch signal 9 branched out of the operation signals 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for examining the dynamic characteristics of a controlled object, that is, a system identification apparatus, and more particularly to an identification apparatus for a multiple input / output control system.

[0002]

2. Description of the Related Art System identification is to obtain the dynamic characteristics of input / output data of a controlled object. FIG. 4 is a block diagram showing the relationship between a conventional control target and a system identification device. That is, the system identification device 1 is controlled by the control target 2
Is input as an input, the output of the controlled object 2 is observed, the dynamic characteristics of the controlled object are calculated from the input / output data of the controlled object, and the input / output relationship is obtained. A method generally used for system identification is a method called the least squares method. The least squares method is a method of calculating so that the square of the error between the calculated result and the actual value is minimized. Input / output data is obtained at certain time intervals for processing by a computer. Therefore, the dynamic characteristic is also expressed corresponding to a certain time interval. This expression is called a discrete-time expression, and the transfer function expression uses the Z-transform expression.

FIG. 5 shows the input / output relationship of the controlled object, and shows the case of three inputs and three outputs. uj (j = 1,
2,3) is the input and yk (k = 1,2,3) is the output. Mutual transfer characteristics are represented by a total of nine transfer functions. y
The transfer function to 1 is G1, G2, in order from u1, u2, u3.
G3 and the transfer functions to y2 are G4, G5, G6,
The transfer functions to y3 are G7, G8 and G9.

The number of inputs is r, the number of outputs is m, the transfer function of each part is Gi (i = 1,2, ..., mr), and the form of the equation is z ^-1 (discrete) (Expressing a step delay in time)

[0005]

[Equation 4]

Coefficients gd (j) and gn of each delay in the above equation
(I, j) can be obtained by solving the following equation, and Gi can be obtained using it.

[0007]

[Equation 5]

[0008]

[Equation 6]

Here, the vector u _i is determined as follows. The number of vector elements is (n · r).

[0010]

[Equation 7]

By the above method, the transfer function Gi from an arbitrary input end to the output end can be obtained. This method is a method described in Sagara et al., "System Identification", Society of Instrument and Control Engineers.

The operation signal applied to each input end can be separated from the output end from which input end by using a signal having a low cross-correlation.

[0013]

However, in the conventional identification device, the denominator of each transfer function is common. In a process or the like, the output is temperature or pressure, and the response is obviously different. For example, pressure responds much faster than temperature. If the transfer function has a common denominator, the denominator must include both the slow component and the fast component. However, when a slow component is actually included in the fast output, it is necessary to cancel the slow component by the molecule in order to express the fast output. For this reason, according to the conventional system identification method, the number of parameters of the transfer function, so-called order, is significantly increased. If the order becomes unnecessarily high, there is a problem in that the response changes greatly even with a small error in the coefficient, and the identification accuracy decreases.

An object of the present invention is to provide a system identification device which can improve the identification accuracy in consideration of the conventional problems as described above.

[0015]

According to the present invention, an input signal is input to each of a plurality of input terminals of a multi-input / output control system to obtain an output signal from each of the plurality of output terminals.
In a system identification device for calculating an input / output relationship of a multiple input / output control system based on the input signal and the output signal, an input means for inputting one of a plurality of output signals, and an output for the input A system identification device comprising: an identification calculation means for performing identification calculation of a part of input / output relations of a multiple input / output control system based on a signal and a plurality of input signals.

[0016]

According to the present invention, an input signal is input to each of a plurality of input terminals of a multi-input / output control system, an output signal is obtained from each of a plurality of output terminals, and the input means outputs one of the output signals. Based on the input one output signal and the plurality of input signals, the identification calculation means identifies and calculates a part of the input / output relation of the multiple input / output control system.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1 is a schematic configuration diagram of a system identification device according to an embodiment of the present invention. That is, one of the system identification devices 1 is provided with an operation signal output end 5 for giving an operation signal 7 (the number of signals is the same as the number of input ends, which are respectively input) to the multi-input / multi-output controlled object 2. And a signal input terminal 6 for inputting an output signal 8 (the number of signals is equal to the number of output terminals and output respectively) output from the controlled object 2 as a result of the operation signal 7 being input to the other.
Is provided.

A switching device 4 for sequentially switching the input output signal 8 is connected to the signal input terminal 6, and the switching device 4 is connected to an identification calculation means 3 for performing identification calculation of each transfer function of the controlled object 2. There is. The branching signal 9 of the operation signal 7 output from the operation signal output terminal 5 is input to the identification calculation means 3, and the switching device 4 is connected to the memory 10 for storing the output signal 8.

FIG. 2 shows the corresponding transfer function when performing the identification calculation on the output y1. That is, for all inputs, only those related to output y1 are identified. The calculation can be performed by the following formula.

Now, let r be the number of inputs and Gi (i = 1,2, ..., r) be the transfer function of each part for any one output, and the form of the equation is z ^-1 ( It represents the step delay in discrete time)

[0022]

[Equation 8]

Coefficients gd (j) and gn of each delay in the above equation
(I, j) can be obtained by solving the following equation, and Gi can be obtained using it.

[0024]

[Equation 9]

[0025]

[Equation 10]

By using the above equation, the transfer functions G1, G2 and G3 relating to the output y1 can be identified in the example of FIG. Next, as shown in FIG. 3, an identification calculation regarding the output y2 is performed. Thus, the transfer functions G4, G5, G6
Can be asked. The identification calculation for the output y3 is performed by the same method. As a result, the transfer functions G7, G8 and G9 can be obtained. In this way all transfer functions can be calculated. At this time, the denominators of G1, G2, and G3 are common, but they are not common to G4, G5, and G6. Similarly, it is not common to G7, G8, and G9. Therefore, it is not necessary to increase the order of the denominator, and each transfer function can be represented by a low order.

As described above, the present invention solves the problem that the order of the transfer function becomes too high, which is a drawback of the prior art. In addition, it does not require new data to solve the problem and does not extend the experiment time.
Further, since the number of outputs is set to 1 and the identification calculation is performed, the size of the matrix required for the operation is small and the storage capacity of the device is small, and the small matrix size requires a short calculation time.

In the above embodiment, one set of the input means and the identification calculation means is used to sequentially switch the output signals to perform the identification calculation. However, the present invention is not limited to this, and the input means and the identification corresponding to each output signal are used. A plurality of sets of calculating means may be provided and the transfer function for each output signal may be calculated in parallel.

Further, in the above-mentioned embodiment, the identification calculation means 3 and the switch 4 are constructed by dedicated hardware, but the same function may be constructed by software using a computer.

[0030]

As is apparent from the above description, the present invention provides the input means for inputting one of the plurality of output signals, the input one output signal and the plurality of input signals. On the basis of this, since it is provided with the identification calculation means for performing identification calculation of a part of the input / output relation of the multiple input / output control system, it has an advantage that the identification accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a system identification device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control target showing an operation principle in the embodiment.

FIG. 3 is a block diagram of a control target showing an operation principle in the embodiment.

FIG. 4 is a block diagram showing a relationship between a conventional control target and a system identification device.

FIG. 5 is a block diagram of a control target showing an operation of a conventional identification device.

[Explanation of reference numerals] 1 system identification device 2 controlled object (multi-input / output control system) 3 identification calculation means 4 switch (input means)

Claims (4)

[Claims] 1. An input signal is input to each of a plurality of input terminals of a multi-input / output control system to obtain an output signal from each of the plurality of output terminals, and based on the input signal and the output signal, In a system identification device for calculating an input / output relationship of an input / output control system, an input means for inputting one of the plurality of output signals, the input one output signal and the plurality of input signals Based on the above, there is provided an identification calculation means for identifying and calculating a part of the input / output relation of the multiple input / output control system. 2. The system identification device according to claim 1, wherein a plurality of sets of input means and identification calculation means are provided corresponding to a plurality of the output signals. 3. The system identification device according to claim 1, wherein the input means and the identification calculation means are provided in one set and sequentially process the plurality of output signals. 4. A part of the input / output relationship of the multiple input / output control system is
The number of input terminals is r, the input signal is uj (j = 1 to r), any one output signal is y, and each transfer function between the input signal uj and the output signal y is Gi (i = 1 to r). The system identification device according to claim 1, wherein the system identification device is obtained from each transfer function Gi obtained by solving the following equation. [Equation 1] [Equation 2] [Equation 3]