SU1509488A1 - Apparatus for limiting dynamic loads in excavator mechanism - Google Patents

Abstract

The invention relates to electrical engineering and can be used in electric drives of excavator mechanisms, drilling rigs, rolling mills and other machines. The goal is to increase the effectiveness of limiting dynamic efforts by increasing the speed and noise immunity of the device. The device contains adders 1,2,3, voltage regulators 4 and current 5, valve converter 6, current sensors 7, voltage 8 and moment 10 in the elastic element 11 between the electric motor (ED) 9 and the actuator 12, non-linear elements 13 and 15 with a dead band, a differentiating amplifier (RC) 14, a differentiating link 16, a filter 17, and a reference signal source 18. Converter 6 is adjustable. The magnitude of its output voltage (current) depends on the level of the output signal of the regulator 5. Current sensor 7 is installed in the core of the ED 9 and forms a feedback loop, the output of which is proportional to the operating current of the ED 9. The reference signal source 18 determines the acceleration rate (deceleration) ED 9, and the remote control 14 generates a signal depending on the amplitude and rate of change of torque. Due to this, effective damping of any oscillations exceeding the magnitude of the stopping moment value is carried out. The noise immunity of the dynamic load limiting circuit increases due to the series-connected element 15 and link 16. At the time when the signal at the output of the control unit 14 is close to the "saturation" zone, element 15 is opened, and link 16 is turned on in the feedback circuit. The "saturation" mode of the remote control is excluded. 14. 2 Il.

Description

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about with

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10 in the elastic element 11 between the electric motor (ED) 9 and the actuator 12, the nonlinear elements 13 and 15 with the dead zone, the differentiating amplifier (DU) 14, the differentiating element 16, the filter

17 and task source 18. Converter 6 is adjustable. The magnitude of its output voltage (current) depends on the level of the output signal of the regulator 5. Sensor 7

current is installed in the circuit of ED 9 and. forms a feedback loop, the output signal of which is proportional to the working current of ED 9. Source

The 18 signal of the task determines the acceleration (deceleration) rate of ED 9, and the DN 14

generates a signal depending on the amplitude and rate of change of the torque. Due to this effective damping of any oscillations, exceeding in magnitude the stopping moment value, is carried out. The noise immunity of the dynamic load limiting circuit increases due to the Hbw element 15 and the link 16 being sequentially connected. At the time when the signal at the output of the control unit 14 is close to the zone of pressure, element 15 opens and the link 16 is connected to the feedback circuit of the control unit 14. Thus the saturation mode of the remote control is excluded. 14. 2 Il.

The invention relates to electrical engineering and is intended for use in electric drives of excavator mechanisms, as well as drilling rigs, rolling mills and other machines.

The aim of the invention is to increase the efficiency of limiting dynamic forces by increasing the speed and noise immunity of the device.

Figure 1 shows the functional diagram of the device j in figure 2 - the timing diagram of the signals of the device.

The device (Fig. 1) contains the first 1, second 2 and third 3 adders, voltage regulator 4, current regulator 5, valve converter-6, current sensor 7, voltage sensor 8 electric motor 9, moment sensor 10 in an elastic element 11 between the motor 9 and the actuator 12, the first nonlinear element 13 with the deadband, a differential amplifier 14, the second nonlinear element 15 with the deadband, the differentiation link 16, the filter 17, and the reference signal source 18.

Adders 1–3 have a unit gain over the entire range of control actions.

Viy.

Voltage regulator 4 and current 5,

for example, proportionally integral, are used to adjust the corresponding parameters of the electric motor 9.

The valve converter 6 is adjustable, the magnitude of its output voltage (current) depends on the level of the output signal of the regulator 5. The current sensor 7 installed in the core of the electric motor 9 forms a feedback loop, the output of which is proportional to the operating current of the electric motor 9

Voltage sensor 8 generates a signal proportional to the average value of the output voltage of converter 6.

The torque sensor 10 generates at the output a signal proportional to the moment on the controlled shaft in the kinematic chain between the electric motor 9 and the actuator 12.

Link 11 and 12 represent the working bodies of the excavator. The first wedge link 13 has a dead zone ± C (FIG. 2) and a unit transfer coefficient in the range exceeding (in absolute value) the level ± C.

Differentiating amplifier 14 has a transfer function, for example, successively included two forcing links

w (p) (t, p + -1- 1) (1)

where T and T are constant times.

The maximum output signal of the amplifier 14 corresponds to the value of A.

The second non-linear element 15 is made with a dead zone of 0 ± (А-б), where Л А, and has a single transmission coefficient in the range exceeding the value в,

The transfer function of the link 16 corresponds to

W (p) TP + 1,

where T is constant time.

The filter 17 implements the transfer function, for example, aperiodic link.

W (p)

one

TFR + 1

with a constant time Tf.

The reference signal source 18 determines the acceleration (deceleration) rate of the electric motor 9.

25 liters 14 is reduced by the value of Dx, proportional to the volt-second area S (Fig. 2), which is equivalent to reducing the gain of the amplifier 14 for the useful component of the input

The device works as follows.

When the torque M of the stop value Mr-p at the output of the element 13 exceeds the torque M, the voltage of the 30 signal appears.

A swarm is fed to the differentiator. To exclude this under-amplifier 14. The forcing links of the differentiating amplifier 14 are tuned accordingly to compensate for the constant time of the controlled converter 35 and the electromechanical

constant drive time. The voltage of the differentiating amplifier 14 through the filter 17 is fed to the adder

.2, forming a change in the task of regulation - 40 is moving along the trajectory a-b

the torus 5 is the current of the required amplitude and (Fig. 2), which lies below the phase level, preventing the oscillations of the dynamic moment and its transformation over the stopping value. When uvilitatka serve elements 15 and 16. At time t, when the signal at the output of the amplifier 14 is close to the zone of expansion, the element 15 is opened and the differentiating link 16 is included in the feedback circuit of the amplifier 14. Due to the increase in the constant time 14 its output sig + a. In the interval, recharge of the forcing link 16 occurs. At point C, element 15 is turned off, the output voltage of amplifier 14 is abrupt

a boost of the boost link 16. In unit C, the element 15 is turned off, the output voltage of the amplifier 14 is abrupt

moment of the signal differential 45

Amplifier 14 has a polarity, Achieves the trajectory of movement of the signal opposite to the polarity of the regulating x, and (t) + x (t).

14 p

Thus, the introduction of the second nonlinear element 15 and link 16 eliminates the saturation mode of the amplifier 14, increasing the home stability of the counter for limiting the dynamic loads of the excavator.

pa, and pressure irts. When Up | y Orts, the polarity of the voltage at the input of current regulator 5 is changed, and the motor is switched to regenerative braking. Due to the fact that the differentiating amplifier generates a signal, which depends on both the amplitude and the rate of change of the torque, effective damping of any oscillations exceeding the magnitude of the stopping moment of the moment takes place. .

The noise immunity of the limiting circuit of dynamic loads is achieved by the introduction of element 15 and link 16. Suppose that at time Cd (Fig. 2) the input of adder 3 (Fig. 1) is affected by high-frequency disturbance Xp (t), which is summed up from the signal component The output of element 13. We assume that the informative signal x. (t) at the output of amplifier 14 during the time of interference is constant (figure 2). At a sufficiently high level of the signal of interference at time t, the resulting output signal x (t ) and Xn (t) amplifier 24 reaches 3 us saturation of the operational amplifier and is limited to the range

level + A. (here (t) signal interference after its passage, value through the differential amplifier 14). As a result, the useful component (t) of the output voltage of amplification 14 decreases by an amount Dx proportional to the volt-second area S (Fig. 2), which is equivalent to reducing the gain of amplifier 14 for the useful component of the input signal.

To eliminate this drawback, elements 15 and 16 serve. At time t, when the signal at the output of amplifier 14 is close to the zone of extension, element 15 is opened and differentiator 16 is turned on in the feedback circuit. Due to the increase in the constant time of the amplifier 14 of its output sig (FIG. 2), which lies below the level

+ A. In the interval, recharge of the forcing link 16 occurs. At point C, element 15 is turned off, the output voltage of amplifier 14 is abrupt

Achieves the trajectory of the signal

nal x, and (t) + x (t).

14 p

Thus, the introduction of the second non-linear element 15 and link 16 eliminates the saturation mode of the amplifier 14, increasing the home stability of the circuit limiting the dynamic loads of the excavator.

The proposed device improves the effectiveness of limiting dynamic loads by reacting not only by the magnitude, but also by the rate of change of the load of the mechanism. The device works only in the load, the relay disconnection is excluded, the devices at zero speeds of the drive eliminate the torsional fluctuations of the load when the drive is locked because of the presence of elastic elements in the kinematic chain. By selecting a time constant of the amplifier 14, the required nature of the current transient process is ensured when stopped without introducing additional nodes. The interference immunity of the limiting device is increased.

Claims (1)

Formula 5 A device for limiting the dynamic forces in the excavator's mechanism, including a series-connected source of the reference signal, a first adder, a voltage regulator, a second adder, a current regulator, a valve converter, the output of which is connected to the core of the electric motor, on the shaft of which a sensor is mounted moment, and the output of the latter is connected to the input of the first nonlinear element, the current sensor. An electric motor included in the circuit, the output of which is connected to the second input of the second adder, a voltage sensor, the input of which is connected to the output of the valve converter, and the output of the voltage sensor connected to the second input of the first adder, in order to increase the efficiency limiting dynamic forces by increasing speed and noise immunity, it is equipped with a third adder, a differentiating amplifier, a filter, a second nonlinear link and a differentiating link, while The third adder is connected via a serially connected differentiating amplifier and filter to the third input of the second adder, the output of the differentiating amplifier is also connected via a serially connected second nonlinear link and the differentiating link is connected to the second input of the third adder, the first nonlinear output is connected to the first input. an item. FIG. 2