JP6119154B2 - Swing control device for work machine - Google Patents

Description

  The present invention relates to a turning control device for a work machine such as an excavator that drives a turning body by an electric motor.

  The background art will be described using an excavator as an example.

  As shown in FIG. 6, the excavator is mounted on a crawler-type lower traveling body 1 so that an upper swing body 2 can be swung around an axis O perpendicular to the ground, and a work attachment 3 is attached to the upper swing body 2. Is configured.

  In this excavator, the hybrid type or the electric type uses an electric motor as a turning drive source, and the turning electric motor is driven by a capacitor or a generator motor to generate a turning driving force.

  In this electric swing type work machine, as described in Patent Document 1, an operation amount of a swing operation means for issuing a turn command (hereinafter, a case where an operation lever is used as the swing operation means will be described. The target speed and acceleration are determined according to the `` lever operation amount '', and an acceleration / deceleration pattern is generated according to this acceleration, and the turning motor is controlled according to the deviation between the command speed based on this pattern and the detected actual speed. A technique for performing feedback control for controlling the speed is known.

  In addition, in this known technique, trapezoidal acceleration / deceleration control (delay control) is performed as an acceleration / deceleration pattern that gives a constant gradient to the rising speed during acceleration in order to realize smooth turning acceleration / deceleration. .

  A technique for performing S-curve acceleration / deceleration control as delay control is also known.

WO2006 / 054541

  When performing such feedback control and delay control such as trapezoidal acceleration / deceleration control, for example, restraint by external force, such as swivel pressing work in which the tip of the work attachment 3 is pressed against the wall surface of the groove to form the wall surface. In response to the operation in which the actual speed of turning is almost zero, the deviation between the command speed and the actual speed increases, and the motor torque is maximized accordingly.

  For this reason, when the restriction is removed, the upper-part turning body 2 tries to make a sudden turn with the maximum torque of the turning electric motor.

  In this case, in normal feedback control in which delay control is not performed, turning can be stopped immediately by returning the lever to the neutral position. However, in feedback control with delay control as in the known technique described in Patent Document 1, stop is performed. A time delay occurs until the lever is returned to neutral, and a “swivel pop-out phenomenon” occurs in which the turn accelerates.

  As a countermeasure against this point, the delay until stopping can be reduced by setting the acceleration large. However, this causes a problem that the operability is deteriorated, such as an excessive acceleration during a normal turn and a shock.

  Accordingly, the present invention provides a turning control device for a work machine that can suppress a turning-out phenomenon and can ensure an appropriate acceleration performance during normal turning.

As means for solving the above-mentioned problems, the present invention comprises a turning electric motor that drives the turning body to turn, a turning operation means that issues a turning command, and a control means that controls the operation of the turning electric motor. Is
(i) The target speed according to the operation amount of the turning operation means and the target acceleration set in advance so as to cause a time delay in the speed response of the turning electric motor with respect to the operation of the turning operation means. Set the command speed for the swing motor,
(ii) Obtain a deviation between the command speed and the actual speed that is the actual rotational speed of the swing motor, and perform feedback control according to the speed deviation;
(iii) set in advance limit value as a value capable of ensuring a torque required for acceleration with the above speed deviation during acceleration,
(iv) At the time of acceleration, the command speed is limited so that the speed deviation does not exceed the limit value.

  According to this configuration, in the swing type work machine that performs feedback control and delay control, the magnitude of the deviation between the command speed and the actual speed is limited, that is, the speed deviation is not excessive. At the time of release from the motor, the “torque jumping phenomenon” can be suppressed by suppressing the motor torque.

  In this case, since the acceleration is not increased, there is no possibility that the acceleration becomes excessive during normal turning.

  Further, in order to limit the speed deviation to the last, by setting the limit value as a value that can secure the torque necessary for acceleration, the acceleration performance during normal turning can be ensured.

  In the present invention, it is desirable that the control means sets the limit value of the speed deviation as a value capable of generating a maximum torque in the swing electric motor (claim 2).

  If the limit value is set too small, the torque generated in the electric motor is also reduced and the acceleration during normal turning is worsened. In this regard, according to the configuration of the second aspect, the limit value is set as a value at which the turning electric motor can generate the maximum torque, so that it is possible to ensure good acceleration performance during normal turning.

  In the present invention, it is preferable that the control means sets the limit value in consideration of a speed fluctuation due to disturbance of the swing electric motor.

  According to this configuration, it is possible to prevent torque fluctuation due to the influence of noise and disturbance of the speed sensor for detecting the actual speed.

  According to the present invention, it is possible to suppress the turning-out phenomenon and to ensure proper acceleration performance during normal turning.

It is a system configuration figure of a control device concerning an embodiment of the present invention. It is the same control block diagram. It is a figure which shows the relationship between the operation amount of turning in the same apparatus, and target speed. It is a figure which shows the relationship between time, speed, and acceleration similarly. It is a flowchart for demonstrating the effect | action of the apparatus. It is a schematic side view of the shovel as an example to which the present invention is applied.

  The embodiment is applied to an electric or hybrid excavator.

  FIG. 1 shows a system configuration of this control device, and an operation amount (lever operation amount) of an operation lever 4 as a turning operation means is detected by an operation amount detection means 5 and inputted to a controller 6 which is a control means. .

In addition, motor rotation speed detection means 8 for detecting the rotation speed of the swing motor 7 is provided, and the actual speed of the swing motor 7 detected by the detection means 8 is sent to the controller 6.

  A map showing the relationship between the lever operation amount and the target speed shown in FIG. 3 is preset and stored in the controller 6, and the target speed is obtained from the lever operation amount.

  Further, a target acceleration for performing delay control (in this example, the trapezoidal acceleration / deceleration control shown in FIG. 4) is set in advance, and the target speed, the detected actual speed, and the set target acceleration are used. The command speed for the swing motor 7 is calculated and sent to the swing inverter 9.

  More specifically with reference to the control block of FIG. 2, the target speed is set by the lever operation amount, and the command speed is set from the target speed and the target acceleration.

  Here, the command speed in the trapezoidal acceleration / deceleration control is obtained as follows.

  The target speed is V0, the target acceleration is A0, the command speed in the current control cycle is Vref (n), and the command speed in the previous control cycle is Vref (n-1). Ts is a control cycle.

・ When V0> Vref (n-1) (when the target speed is higher than the previous command speed)
Vref (n) = Vref (n−1) + A0 × Ts
However, in the calculation, when Vref (n)> V0 (when the command speed exceeds the target speed), Vref (n) = V0.

・ When V0 <Vref (n-1) (when target speed is lower than previous command speed)
Vref (n) = Vref (n−1) −A0 × Ts
However, in the calculation, when Vref (n) <V0 (when the command speed is less than the target speed), Vref (n) = V0.

  Then, a deviation (speed deviation) between the command speed and the actual speed obtained as described above is calculated, and a command torque corresponding to the speed deviation is output to the swing inverter 9.

  Here, in this control device, a limit value as an upper limit value of an allowable speed deviation is set in the controller 6 in advance, and the command speed for the swing motor 7 is limited so that the speed deviation does not exceed the limit value (limitation). Output commanded speed).

More specifically, the speed deviation limit value Δmax is determined from the maximum torque (determined by the motor performance and specifications) Tmmax of the swing motor 7, the speed control gain Kvfb, and the speed variation ΔVh due to disturbance of the swing motor 7.
ΔVmax = Tmmax ÷ Kvfb + ΔVh
This is set and stored. That is, the limit value ΔVmax is basically set based on a value at which the turning electric motor 7 can generate the maximum torque.

  Then, when the motor actual speed V is positive (for example, left turn) during acceleration, it is determined whether or not the command speed Vref is greater than the actual speed V. If it is greater, a speed deviation ΔV is calculated.

Next, it is determined whether or not the speed deviation ΔV is larger than the limit value Δmax.
Vref = V + ΔVmax
And

On the other hand, when the motor actual speed V is negative (same as the right turn), it is determined whether or not the command speed Vref is smaller than the actual speed V. If it is smaller, the speed deviation ΔV is calculated. If it is smaller than (−ΔVmax), the command speed Vref is
Vref = V−ΔVmax
And

  The value of the obtained command speed Vref is stored for command speed calculation in the next control cycle.

Furthermore, the motor torque Tm is calculated from the command speed Vref and the actual speed.
Tm = Kvfb × (Vref−V)
This is sent to the swing inverter 9 as a command torque for the swing motor 7.

  In the swing inverter 9, the voltage of the swing motor 7 is controlled so that the motor torque becomes the command torque.

  The contents of the speed deviation limitation will be described with reference to the flowchart of FIG. 5. A speed deviation limit value Δmax is calculated in step S1, and it is determined in step S2 whether V> 0 and Vref> V.

  In the case of YES here, the speed deviation ΔV is calculated in step S3, the speed deviation ΔV is compared with the limit value ΔVmax in step S4, the command speed Vref is calculated in step S5, and the command speed Vref calculated in step S6 is stored. Are performed, and the process returns to step S1.

  On the other hand, if NO in step S2, it is determined whether V <0 and Vref <V in step S7. If YES, speed deviation ΔV is calculated in step S8, and speed deviation ΔV and the limit value (step S9). -ΔVmax), and the command speed Vref is calculated in step S10. Then, the process proceeds to step S6.

  If NO in step S4 (speed deviation ΔV is equal to or less than limit value ΔVmax), if NO in step S7 (V0 <0 and Vref <V is not satisfied), NO in step S9 (speed deviation ΔV is less than limit value −ΔVmax) In the case of (1), no speed limitation is performed, and the command speed Vref based on the speed deviation ΔV is used as it is, and the process directly proceeds to step S6.

  In this way, in an excavator that performs feedback control and delay control, in order to limit the speed deviation between the command speed and the actual speed, that is, the speed deviation does not become excessive. It is possible to suppress the “turn-out phenomenon”.

  In this case, since the acceleration is not increased, there is no possibility that the acceleration becomes excessive during normal turning.

  Further, in order to limit the speed deviation to the last, by setting the limit value as a value that can secure the torque necessary for acceleration, the acceleration performance during normal turning can be ensured.

  In addition, in the embodiment, since the limit value of the speed deviation is set as a value at which the turning electric motor can generate the maximum torque, the motor torque becomes small as in the case where the limit value is set to be too small, and during normal turning. There is no possibility that acceleration will deteriorate, and good acceleration performance during normal turning can be ensured.

  Further, since the limit value is set in consideration of the speed fluctuation due to the disturbance of the swing electric motor 7, the torque fluctuation due to the influence of the noise of the speed sensor for detecting the actual speed and the disturbance can be prevented.

  By the way, although the case where trapezoidal acceleration / deceleration control is taken as the delay control is taken as an example in the above embodiment, the present invention can also be applied to the case where S-shaped acceleration / deceleration control is taken as in the above embodiment.

  The present invention is not limited to excavators, and can be widely applied to swivel work machines such as deep hole excavators, crushers, cranes, and the like that are configured with the excavator as a base.

2 Upper swing body 4 Operation lever (turning operation means)
5 Operation amount detection means 6 Controller (control means)
7 slewing motor 8 motor rotation speed detection means 9 slewing inverter constituting control means

Claims (3)

A turning electric motor for driving the turning body to turn, turning operation means for issuing a turning command, and control means for controlling the operation of the turning electric motor, wherein the control means comprises:
(i) The target speed according to the operation amount of the turning operation means and the target acceleration set in advance so as to cause a time delay in the speed response of the turning electric motor with respect to the operation of the turning operation means. Set the command speed for the swing motor,
(ii) Obtain a deviation between the command speed and the actual speed that is the actual rotational speed of the swing motor, and perform feedback control according to the speed deviation;
(iii) set in advance limit value as a value capable of ensuring a torque required for acceleration with the above speed deviation during acceleration,
(iv) A turning control device for a work machine, wherein the command speed is limited so that the speed deviation does not exceed the limit value during acceleration.
  2. The turning control device for a work machine according to claim 1, wherein the control means sets the limit value of the speed deviation as a value that can cause the turning electric motor to generate a maximum torque.   3. The turning control device for a work machine according to claim 1, wherein the control means sets the limit value in consideration of a speed fluctuation due to disturbance of the turning electric motor.

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