SU1192089A1 - Device for forming specification of electric drive velocity - Google Patents

Description

The invention relates to electrical engineering, in particular to electric drives with elastic coupling between engine and mechanism, and can be used in electric drives of manipulators and industrial robots, excavators and cranes, elevators and lifts, rolling mills and papermaking machines, where the presence of elastic mechanical coupling can cause mechanism oscillations reducing the control accuracy, increasing the dynamic loads in the mechanism and the working equipment and requiring a significant increase in the duration of ne transition processes, which reduces the performance of machines.

The purpose of the invention - an exception vibrational mechanism ¹⁵ Nij start and stop the modes.

FIG. 1 shows a diagram of the device; in fig. 2 - graphs of changes in the signals in the device; in fig. 3 - rate of change of graphics, acceleration and jerk Me- ₂ of the drive mechanism of the process of acceleration using the invention.

The device contains relay element 1 and integrating element 2, included in series and covered by negative feedback, as well as additionally 25 entered aperiodic links 3 and 4 and adder 5 with four inputs, while the input of the first aperiodic link 3 is connected to the output of the relay element 1, the input of the second a delay element 4 is connected to the output of the first delay element 3, and ³⁰ rows vho- adder 5 are connected to the outputs of the relay member 1, integrating unit 2, first 3 and second 4 aperiodich'eskih units.

FIG. 2 shows the characteristic ₃₅ (in acceleration mode) changes over time of the output signal of the integrating link 2 (curve 6), the output signal of the aperiodic link 3 (curve 7), the output signal of the aperiodic link 4 (curve 8) and the output signal of the adder 5 (curve 9) . 40

FIG. Figure 3 shows diagrams (in acceleration mode) of the speed of the mechanism (curve 10), the acceleration of the mechanism (curve 11), and the jerk (curve 12).

The device works as follows. ₄₅

At the beginning of acceleration, when the JS speed command signal arrives at the input of the relay element 1, to which the drive should accelerate, the Jz signal appears at the output of the relay element 1, determining the allowable acceleration of the drive. This 50 signal is fed to the input of the integrator 2 and causes a linearly increasing signal to appear at its output (curve 6 in Fig. 2). At the same time, the output signal of the relay element 1 is fed to the input of the first aperiodic link 3, the output signal of which changes according to the law of first-order exponents (curve 7 and ka of Fig. 2).

The first-order output exponential signal from the output of the first aperiodic link 3 is fed to the input of the second aperiodic link 4 and causes a signal to appear at its output, changing according to the law of the second order exponent (curve 8 in Fig. 2).

The output signals of the relay element 1, the integrating link 2, the first 3 and the second 4 aperiodic links arrive at the four inputs of the adder 5 and provide a change at its output (and device output) of the signal Tsvyh in accordance with the dependence

-K41 - (I μ (1)

where the gains for each input of the adder 5 are selected taking into account the parameters of the electric drive

Κι =; TO,

- B,) (// * + / b): = T _y (2 + ^ - 2ξ,

- to (1 - + / “).

where τΐϋηαχ, £ max - the maximum speed and acceleration of the electric drive;

the time constant of the elastic Im-Na _connection between the electrode and the gate

Lem and mechanism;

/ ₆ , Д - reduced moments of inertia of the electric motor and mechanism;

C is the elastic stiffness; the relative attenuation coefficient of the elastic coupling;

K = Crc / <6s

Κδτ

Krs - gain controller speed;

Kbs, Ky - gear ratios of speed and current sensors;

Xia F - the proportionality coefficient between the armature current and the motor torque.

The nature of the change in the output signal of the device is characterized by curve 9 in FIG. 2

To obtain the required signs of the signals when implementing dependency (1), aperiodic links 3 and 4 can be made inverting or their outputs must be connected to different inputs of adder 5 (inverting and non-inverting).

Arriving at the input speed controller

the drive, the output signal of the device provides a smooth change in the speed of the mechanism of the drive without Kole3

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gangs and overshoots (curve 10 in Fig. 3). in accordance with the dependence

t _u uu / K8s ⁼ m _y ~ ⁽¹ - ^{e </ Tu)} - ^(1-

- 2 ^) [1 ^- (1 + 1, (2)

which follows from the solution of the differential equation describing the movement of the electric drive under the action of the control signal ΕΙβμχ, coming from the output of the device for generating a speed reference signal

*) (t2 _Lm + 9 £ y \ x

K ’(C> 'V y 1e' '

X ^- T-) +

+ ™ * = + 2 ^^^ -) ·

The first and second derivatives of the expression obtained, which characterizes the change in speed of the mechanism of the electric drive mechanism, determine the change in acceleration just as smooth and limited by acceptable values (curve 11 in Fig. 3) and jerk p _m (curve 12 in Fig. 3).

When the output signal of the integrating link 2 reaches a predetermined maximum value of ЕБс at the device input, the negative feedback covering the relay element 1 and the integrating link 2 provides an almost abrupt reduction of the output signal of the relay element 1 to zero, the signal arriving at the first input of the 5 s disappears output of the relay element 1, the output signal of the integrating link 2 stops changing and remains at the maximum level (curve 6 in Fig. 2), and the output signals of the first 3 and second 4 aper odic units decrease smoothly to zero on the laws of first and second order exponential (curves 7 and 8 in FIG. 2).

In this case, the speed of the mechanism smoothly proceeds to the steady-state value without oscillations and overshoots (curve 10 in Fig. 3), the acceleration of the mechanism (curve 11) justly decreases to zero with a limited jerk value (curve 12).

Such a nature of speed change, acceleration and jerk at the transition to a steady-state speed is determined by the nature of the change in the output signal of the device for generating a speed reference signal at this stage of movement (curve 9 in Fig. 2) and is justified by expressions similar to the above.

Similar smooth transients are provided by the device in the braking and reverse modes of the electric drive with the exclusion of oscillations and overshoots.

The inclusion of a job generation device in the drive control system can be different, the essence of the invention does not change.

So, the adder 5 introduced into the device allows to simplify the adjustment of the device and the electric drive as a whole, however, if necessary, the outputs of the relay element 1, the integrating link 2, aperiodic links 3 and 4 can be connected to the input control circuits of the electric drive (input of the speed or voltage regulator case, perform the functions of the adder), which reduces the number of elements used. In addition, given that the gain of the adder 5 on the output signal of the relay element 1 (i.e. Κι) is inversely proportional to the gain of the speed controller Kpc, the output of the relay element 1 can be connected not to the input of the adder 5 (or to the input of the speed regulator that performs functions of this adder), and transfer through the speed regulator (or voltage) and connect it to the input of the element following the speed regulator (for example, to the input of the current regulator), taking the gain of this signal to be K = (/ m + C) K / KSST F, which will make it easier to tune this signal, especially with a high gain speed controller.

The invention allows to exclude oscillations of the electric drive mechanism, while the known devices only reduce the amplitude of these oscillations to acceptable values due to a significant increase in the duration of the rise of the control signal and thereby an increase in the time of transients.

With the same transient time, the invention allows to reduce the maximum dynamic loads by 25% and increase the reliability of the electric drive. In the same case, when braking, the invention allows the mechanism to stop in a predetermined position, while with a known device, the mechanism will oscillate around a stopping point with an amplitude equal to 25% of the maximum mean deviation determined by the allowable acceleration of the drive.

If, by increasing the duration of the rise of the speed reference signal in a known device, the amplitude of oscillations is reduced to an acceptable value (for example, 5%), then the invention reduces the transient time compared to the known one by 30— 80% (the time gain will be pain, more, the larger the value of the allowable acceleration of the drive compared to the maximum value of the drive speed).

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Thus, the invention allows to exclude oscillations of the electric drive mechanism in the start-up modes and thereby increase the reliability of the electric drive and control accuracy, as well as reduce the time of transient processes.

Claims (2)

A DEVICE FOR THE FORMATION OF A JOB SIGNAL SIGNAL, SPEED OF AN ELECTRIC DRIVE with an elastic coupling between an electric motor and a mechanism, containing a relay element and an integrating element, which are connected in series with the purpose of excluding oscillations of the mechanism, in which the starting brakes are applied, they have in place, in order to prevent fluctuations of the mechanism in the start-up mode, in addition, in order to prevent oscillations of the mechanism, they are put into the starting braking modes and they have a device in which they are put into the starting braking modes and the integrating element, which is used in order to prevent oscillations of the mechanism in the starting braking mode and in the mode, they should be set in the start-up mode, in order to prevent the mechanism from vibrating in the start-up mode, the unit will be equipped with the device. the link and the adder with four inputs, while the input of the first aperiodic link is connected to the output of the relay element, the input of the second aperiodic link is connected to you ode first delay element, said adder inputs connected to the outputs of the relay element integrator, the first and second aperiodic links and the output forms an output device. 6803611 > 2 one 1192089