JPH04315202A - Equivalent disturbance compensating method - Google Patents

Abstract

PURPOSE:To execute required equivalent disturbance compensation without executing an integrating operation when an integrating element exists in a control block by directly operating an impressing input amount and operating a state amount based on the inverse function of a transmission function until the input of a controlled system. CONSTITUTION:The disturbance to the controlled system (not shown in the figure) is predictively operated according to an impressing input amount U and a state amount X of this controlled system, and an output Y is fed back to the impressing input amount U of the above-mentioned controlled system. When the above-mentioned controlled system is composed of the integrating element at such a time, the impressing input amount U is directly fetched and the state amount X is calculated by adding the results of multiplying the inverse functions of the transmission functions until the input of the above-mentioned controlled system. Thus, the output Y estimating the disturbance of the above-mentioned controlled system can be obtained without operating a complete integration system (1/S:S is a Laplace operator) and without executing any replacement to a primary delay filter. Namely, a processing due to approximate integrating operation and further an offset processing or the like due to an integration initial value and integration error can be omitted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an equivalent disturbance compensation method using an equivalent disturbance observer that estimates disturbance from inputs and state quantities of a controlled object.

0002

2. Description of the Related Art Generally, in order to obtain an equivalent disturbance compensation value when an integral element is included in a controlled object, an integral calculation is performed using the nominal value of the integral constant of the integral element. As is clear from a mathematical perspective, this integral operation has the problem of accumulation of errors due to the initial value of the integral and the integral operation, and it is difficult to perform a strict integral operation. For example, the integral operation was replaced with a first-order lag filter operation.

0003

As described above, when the controlled object starts operating from a certain state, the initial value at that point must be accurately input. Furthermore, if the operation continues for a long time, a small integral error due to the integral calculation will accumulate little by little, and this value will remain as an offset in the control, making it impossible to continue the correct operation.
It was necessary to perform corrections such as resetting the offset value at appropriate times or constantly subtracting the error. For this reason, in practical terms, when adjustments are made by trial and error or when an integral calculation is attempted to be performed using a first-order lag filter, selection of the constant of the first-order lag filter becomes a problem.

[0004] In view of the above points, the present applicant has previously proposed a patent application entitled "Electric Motor Control Device" dated April 27, 1990. Here, this will be referred to as the previous proposal. An example of the technical idea of the earlier proposal is shown in FIG.

That is, FIG. 5 is a simplified version of FIG. 1 shown in the previous proposal. In FIG. 5, 1 is a stabilizing device, 2 is a controlled object whose main components are a drive-side motor 21, a torsion shaft 22, and a load 23, 3 is an acceleration/deceleration regulator,
4A, 4B, and 4C are limiters, 5 is a feedforward compensation section, 6A, 6B are equivalent disturbance compensation sections, 7 is an inverse function block, and 8 is a non-interference block.

Further, ω* is the command input, ω1 * is the speed command, e is the deviation, ωM is the electric side speed, θ is the torsion, and TL
is the load disturbance, and ωL is the load side speed. Furthermore, in the code,
KC is the torsion spring system, J is the inertia, D is the viscosity system, and S is the Laplace operator. Furthermore, N attached to the symbol represents a nominal value. Here, the disturbance TDL can be regarded as an equivalent disturbance including all load disturbances, parameter fluctuations, etc.

FIG. 5 has been explained in detail in the specification of the previous proposal, so only the above-mentioned symbols will be explained here.
In the FCAN section, the TDLN passed through the filter constitutes an equivalent disturbance observer, and by feeding back this, equivalent disturbance compensation means is applied.

[0008] Here, when formula 3 related to FIG. 1 in the previous proposal is transformed, it becomes formula (2). TDL=(△ω′/S)・KCN−(JLNS+D
LN)・ωL ………………… ■

[0009] Then, if we faithfully execute such equation
)・KCN] must be integrated. To this end, accurate integral calculations cannot be performed unless initial values are taken in. The reason why it is generally said that it is difficult to perform a complete integral operation is because the integral operation value becomes inaccurate due to these factors. Therefore, in general, calculations are often performed using a first-order lag filter as an integral calculation.

If the (1/S) integral operation is replaced with the first-order lag filter operation of the following equation, this becomes equation (2). [T/(1+TS)]=1/[(1/T);S]
≒1/S
…………………………………
■Therefore, [(1/T)≪S] Therefore, (T≫S). From this, if the integration time constant T is selected to be a large value with respect to the operating frequency of the system, an equivalent integral calculation is performed.

[0011] Therefore, [KC・(1/S)・△ω
It has been generally calculated in the recent past by replacing [KC .T(1+TS).Δω'] for . by the way,
If the FCAN block in FIG. 5 is modified, it can be shown as shown in FIG. 6.

0012

[Means for Solving the Problems] From the calculation formula shown in FIG. 6 and equation (2), it is possible to perform block conversion as shown in FIG. . This will be further explained in detail in terms of effects.

[0013]

[Operation] Here, explanation will be made with reference to FIG. 2, which shows a simplified version of the FCAN block in FIG. 5 as a basic block diagram in which an integral calculation block is included in the controlled object. That is, when there is an integral operation in the controlled object 2, in order to estimate the disturbance T from the input U and state quantity X of the controlled object, the nominal values of the control variables are set as KN, JN, and DN, respectively, and the estimated disturbance value TD can be expressed by the following formula.

[0014] U・(KCN/S)−(JNS+DN)X=T
D ……………………… ■If this is made into blocks, it will look like the one shown in Figure 2. At this time, the integral (1/S
) cannot be easily realized as an integral operation as described above, and the calculation up to the output Y of the disturbance estimation observer is expressed as a formula. Y=(S/KN)TD=(S/KN)[U・(KCN/S)−(J
N S+D)・X] =U-[(S/K)(JN
S + DN )

When this is divided into blocks, it becomes as shown in FIG. In this block, in order to estimate the disturbance of the controlled object, the applied amount input U is directly taken in, and the state amount X is multiplied by the inverse function of the transfer function up to the input of the controlled object. It can be found by By doing so, the disturbance estimation output Y can be obtained without having to perform calculations using a complete integral system (1/S) as in the case shown in FIG. 3, and without replacing it with a first-order lag filter.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, a torsional vibration control system will be described in which a so-called torsional system exists between an electric motor and a load. FIG. 4 shows an embodiment to which the present invention shown similar to FIG. 5 is applied. That is, this is a case where the load side speed ωL is applied to the second equivalent disturbance compensation means for the controlled object from the load side torsion angle.

Here, since it is physically impossible to return to the point Δω of the second compensation output, the second compensation output is returned to the point T* corresponding to the torque command of the drive side motor. It goes without saying that in order to return to this point, it is the same as the previous proposal, which is performed through the inverse function block 7 of the transfer function of the drive side motor.

[0018]

[Effects of the Invention] As explained in detail above, according to the present invention,
Processing using some kind of near-integral calculation in equivalent disturbance compensation calculation for a conventional system with an integral element in the controlled object,
Furthermore, it is possible to provide an exceptional method in which a program can be constructed using an algorithm that eliminates the need for integral calculations, and is freed from the troublesomeness of offset processing and the like based on integral initial values and integral errors. In addition, the simplified calculation method improves processing time and control accuracy, which has a significant practical effect.

[0019]

[Brief explanation of drawings]

FIG. 1 is a block conversion diagram shown for explaining the solving means of the present invention.

FIG. 2 is a diagram showing basic blocks in which an integral calculation block is included in the controlled object.

FIG. 3 is a diagram shown to facilitate understanding of the effects of the present invention.

FIG. 4 is a system diagram of an embodiment of the present invention similar to FIG. 5;

FIG. 5 is a system diagram shown to explain an example proposed by the present applicant.

FIG. 6 is a diagram in which the FCAN block in FIG. 5 is modified.

[0020]

[Explanation of symbols]

1 Stabilization device 2. Controlled object 3 Acceleration/deceleration adjuster 4A Limiter 4B Limiter 4C limiter 5 Feedforward compensation section 6A Equivalent disturbance compensation section 6B Equivalent disturbance compensation section 7 Inverse function block 8 Non-interference block ω＊ Command input ωM Electric side speed θ Torsion ωL Load side speed J Inertia D Viscosity coefficient S Labrasian operator TDL Disturbance U input X state quantity T Disturbance Y Output TD Disturbance propulsion value

Claims (1)

[Claims] 1. An equivalent disturbance compensation method that estimates and calculates a disturbance to a controlled object from the applied input amount and state quantity of the controlled object, and feeds back the output to the applied input amount of the controlled object, wherein the control An equivalent disturbance compensation method characterized in that when the object is composed of integral elements, the applied input amount is calculated directly and the state amount is calculated from the inverse function of the transfer function to the input of the controlled object.