DD269240A1 - METHOD AND CIRCUIT ARRANGEMENT FOR THE ADAPTIVE CONTROL OF THE SPEED OF ELECTRIC DRIVES - Google Patents

Abstract

The invention relates to a simple method for controlling preferably of electric actuators with veraenderlichen parameters and quickly veraenderlichen Fuehrungs and interference. The invention uses the known principle of identification of the controlled system by comparison with a model and the variation of the regulator by applying a correction signal. The invention relates to special algorithms for the formation of the correction signal. figure

Description

Characteristic of the known technical solutions

The automation of preferably discontinuous production processes requires the use of electric actuators with high dynamic quality in iro-lot quantities. The dynamic quality of these drives should be guaranteed

- independent of effective disturbances

- Regardless of changes in the controlled system, in particular changes in the mechanical moment of inertia of the load

- regardless of the setting of the regulator by humans.

This is achieved by controlling the drive with an adaptive controller. The controller can be designed according to the principles of analogue signal processing, ie. H. with operational amplifiers, analog multipliers, etc. as well as the principles of digital signal processing, d. H. be constructed with microcomputers.

Adaptive controls are known in which the identification of the controlled system takes place by comparison with a controlled system model and in which the action on the controller is effected by applying a correction signal (adaptive or multiplicative). (Schönfeld, R .; Adaptive digital speed and position control of DC-servo drives; First European Conference on Power Electronics and Applications, Brussels, October 16-18, 1985. Report Bd.l., p.2.69, Schönfeld, R. Basics the automatic control, VEB Verlag Technik and Hüthig-Verlag Heidelberg, 2nd edition 1987).

The derivative of the correction signal u from the error signal is carried out with a linear, proportional transfer element with limitation

u = k _k · ε; in the area of IuI S / U ,, ,, _x /

The effectiveness of this circuit with large parameter changes in case of interference and the change of sign of the deviation does not satisfy.

Also known are adaptive controls in which the identification of the controlled system is carried out by comparison with a controlled system model and based on the error signal ε iteratively on the basis of a Gütefunktionais a parameter adjustment of the controller. Such systems require 5 to 10 iteration steps for their effectiveness.

Object of the invention

The aim of the invention is a high dynamic quality of the drive without control adjustment by humans.

Explanation of the essence of the invention

The object of the invention is an algorithm for deriving a correction signal u from the error signal ε such that optimum guiding and disturbing behavior of the drive without regulator adjustment is achieved by the operator, in particular

- When changing the mechanical moment of inertia and the gain factor of the controlled system in the ratio to 1, 50 based on the motor moment of inertia

- at sign change of the deviation of the speed

- when affected by disturbances.

The algorithm should be such that it can be easily realized with both analog and digital controllers. The object is achieved in that the additively aufzuschaltende on the controller output correction signal is formed of several shares:

- Signal component, which is the Feh'ersignal ε proportional

U ₂ = k | · Ε

- Signal component which is proportional to the differential quotient of first or higher order and / or the integral of the controller signal

»2 ·« 21 * If ^{+! T} 22 * g- ⁺ -

+ k ₂₅ · f e. at

- Signal component, which is a function of the error signal ε and the control deviation Δω = (ω << ,, - - ω _{ί ((} )).

u ₃ = Ic ₃ · f ₃ (ε; Δω)

- Signal component of the differential quotient of the first or higher order and / or integral of the function of the error signal ε and the control deviation Δω

df. (<?, L ω) <1 ² fi (f? Λ co )

+ * 45 '/ ^f 4 ⁽ ^' ^{dCO) dt}

The object is further achieved in that the correction signal is subject to an amplitude limitation and a predetermined maximum value ± U _m , _x does not progress

u = f ₆ (u, + U ₂ + U ₃ + U ₄ ); / U / SU _m ".

The controlled system comprises a control variable limit, a proportional gain, an integrator and a Drehzahlmeßglied. The integration time constant is variable. In addition, a disturbance attack. The model of The controlled system corresponds in its structure to the regular track. The integration time constant of the model is set to be

corresponds to the minimum value of the path time constant.

The model error signal is at the same time at a differentiator, an amplifier and a multiplier ah. The means Totalizer added output values of the differentiator and the amplifier are together with your output signal

of the multiplication element at a second summer, whose output signal via a second amplifier, a

Level limiter and a third totalizer at the regulator input or output. On from the control variable deviation by means of Series connection of a second multiplier, a third amplifier and a second level limiter formed Signal is applied to the multiplication element. By the circuit arrangement above equations for U ₁ , U ₂ and U _{3 are} realized. embodiment The drawing shows the signal flow plan of an adept speed control.

The controlled system 1 comprises a control limit Cing 2, a proportional gain 3, an integrator (1 / pTs) 4 and a Drehzahlmeßglied 5, which is represented by a filter function FIL. The integration time constant T, is variable. In addition, a disturbance ζ attacks. The model 6 of the controlled system corresponds in its structure to the controlled system. The integration time constant Tm of the model is set to correspond to the minimum value of the time-of-range constant T ₁ . The error signal ε is in a known manner as the difference of the output control variable of the controlled system ω-, and the output control variable of the model & - formed

From the error signal, a control signal U, derived by the fact that the model error signal ε at the same time to a differentiator 19, an amplifier 16 and a multiplier 10 is applied. The output values of the differentiating element 19 and of the amplifier 16 added together with the output signal of the multiplier element 10 are applied to a second summer 12, the output signal of which via a second amplifier 18, a level limiter 15 and a third summer 11 at the regulator input or output is applied. A signal formed from the control variable deviation by series connection of a second multiplication element 9, a third amplifier 17 and a second level limiter 14 is present at the multiplication element 10

 By the circuit arrangement the following equation is realized:

The control signal U, is limited.

the signal component kj · e · Δω ¹ is internally limited. The control signal is additively connected to the controller output, ie the input of the controlled system so that the draft model remains unaffected. The controlled system model can also be understood as disturbance observer.

Advantages of the solution according to the invention are a high dynamic quality of the drive due to optimal guiding and disturbance variable behavior without regulator adjustment by humans. The solution is thus particularly suitable for actuators, the z. B. be used in discontinuous manufacturing processes.

Claims (4)

1. A method for adaptively controlling the speed of electric drives, the controlled system includes at least one variable parameter and is subject to the influence of disturbances, wherein in the basic control loop is an effective limit, a fixed reference model is used and the model error signal via an adaptive control device to the input of Controlled system is fed, characterized in that the aufzuschüttendes to the controller output or controller input correction signal (U,) is derived directly and without delay using a special algorithm from the model error signal (ε). 2. The method according to claim 1, characterized in that the correction signal is composed of several shares A signal component which is proportional to the error signal (ε) a signal component corresponding to a single or multiple differentiation or integration of the error signal at dt a signal component which is a function of the error signal and the control deviation of the rotational speed U ₃ = k ₃ · f ₃ (ε, Δω) a signal component which is both the differential quotient or integral of the faulty signal and the function of the control deviation of the rotational speed, d ι '( £, & CO ) d ² f ( £ ^{α +1} dt ^4Z dt ^{2 + k} 45 VV ⁱ ' ^{iw) dt} 3. The method according to claim 1, characterized in that the correction signal is subject to an amplitude limitation and does not exceed a predefinable maximum value. u = f ₅ (U ₁ + U ₂ + U ₃ + U ₄ ); / U / SU _max 4. Circuit arrangement for the adaptive control of the speed of electrical drives whose controlled system contains at least one variable parameter and which is subject to the influence of disturbances, wherein in the basic control loop is an effective limitation, a fixed reference model of the controlled system is connected in parallel and the model error signal via an adaptive control device on Input of the controlled system is present, characterized in that the model error signal (ε) at the same time s.ein Ditferenzierglied (19), an amplifier (16) and a multiplier (10), the summed (13) added output values of the differentiator (19) and the Amplifier (16) together with the output signal of the multiplier (10) to a second summer (12) are present, the output signal via a second amplifier (18), a Pegelbegrenjer (15) and a third summer (11) at the Reglerein odor output and a from the control variable deviation (Δω) by means of series connection of a second multiplier (9), a third amplifier (17) and a second level limiter (14) signal applied to the multiplier (10). For this 1 page drawing Field of application of the invention The invention relates to the control of electric actuators with high dynamic quality.