JP4973410B2 - Control device for arm drive of construction machinery - Google Patents

Description

  The present invention relates to a speed control device that moves an arm in a system that uses an electric motor as a power for moving the arm and uses an inverter to drive the electric motor.

Currently, the power for moving the arm of a construction machine having an arm, such as a shovel car, in the left-right direction is a hydraulic motor, and this motor is driven by a high pressure and a large amount of oil generated by a diesel engine and a hydraulic pump. The turning direction and speed are controlled by adjusting the direction and flow rate with a control valve provided between the hydraulic pump and the hydraulic motor. Disadvantages are inefficiency, high pressure, and the use of a large amount of oil, which necessitates maintenance in consideration of environmental and safety such as oil leakage and fire. In order to solve these matters, in recent years, the emergence of small, highly efficient and powerful motors and the small and high performance inverters that drive these motors, the power to move the arm in the turning direction, Combinations of electric motors and inverters have begun to be used.
As shown in FIG. 9, the operating method of the arm driven by this electric motor is such that the state that the operation lever 1 is in the center is 0, the turning speed is positive when tilted to the right, and negative when tilting to the left. A signal is output. In this way, the turning direction and speed are adjusted by tilting the operating lever 1, but play is provided as a dead zone area near the center, and the turning direction is commanded in the direction in which the operating lever 1 is tilted left and right. The degree of turning speed is adjusted by the tilt of the lever.
FIG. 10 shows a configuration diagram of the arm control inverter. The operation lever 1 is operated so that the movement intended by the operator can be realized, and a command signal from the operation lever 1 is output to the filter unit 4. Necessary for removing noise due to mechanical vibration generated by shaking and adjusting the response speed. The output 10 of the filter unit 4 is a command signal of the turning direction and speed to be realized by the inverter and is sent to the control unit 5 of the inverter. In response to this command value, the inverter 7 drives the arm motor 6 to move the arm. Since this filter is used for both acceleration and deceleration, the response speed is the same during acceleration and deceleration.
Patent Document 1 is known as arm control for construction machines. In Patent Document 1, an inverter is used to control an electric motor, and a control signal from a lever is input to the controller of the inverter. However, the filter unit as shown in FIG. 10 is not described.
JP 2001-226077 A

Arm turning speed, which is considered good for safety, workability and environmental friendliness and ergonomics, is a slow response when accelerating, a fast response when decelerating, and no rapid acceleration / deceleration. That is. At present, the response speed is the same for both acceleration and deceleration, and the response speed is often set faster in response to the deceleration. There are problems of lowering and poor workability. In addition, when the vehicle is suddenly decelerated from sudden acceleration, there is a problem that an excessive force due to time differentiation of the speed is applied to the arm, and vibration and noise are generated to deteriorate environmental conditions.

  An object of the present invention is to improve workability, safety, and environmental performance in a construction machine having an arm that uses an electric motor as power for moving the arm and uses an inverter to drive the electric motor. Therefore, an object of the present invention is to provide an inverter device that can adjust the response speed at the time of acceleration and deceleration of the arm operation separately, and further suppress a rapid speed change even with a command of sudden acceleration to sudden deceleration.

Claim 1 of the present invention is a construction machine having an arm, which uses an electric motor as power for moving the arm, and controls the electric motor. The control signal of the inverter is an operation amount of an operating lever for operating the arm. Is input through the filter part,
An acceleration / deceleration determination processing unit that inputs an operation amount of the operation lever to determine acceleration / deceleration, and acceleration
A time constant for the state of acceleration and a time constant for the state of deceleration are set separately, and the time constant for the acceleration state for selecting the acceleration or deceleration time constant according to the determination processing signal of the acceleration / deceleration determination processing unit, Provide a time constant selection part for deceleration state,
The determination value at the time of acceleration / deceleration determination by the acceleration / deceleration determination processing unit is in a range of 1.5 to 2.0 times the noise due to mechanical vibration of the operation lever, and the amount of change due to the operation of the operation lever is When the absolute value relationship is | change amount |> determination value and change amount> 0, it is determined as an acceleration state, and when | change amount |> determination value and change amount <0, it is determined as a deceleration state. , | Change amount | ≦ determination value, it is judged as a steady state .

A second aspect of the present invention is characterized in that the time constant in the selection unit is set such that a response speed at the time of acceleration is slower than a response speed at the time of deceleration .

According to a third aspect of the present invention, a difference between a speed command signal generated by the operation of the operation lever and an output signal of the filter unit is obtained, and the difference is input as a filter difference to the acceleration / deceleration determination processing unit. Determines that the relationship between the determination value and the absolute value of the amount of change due to the operation of the operation lever is | change amount |> determination value, change amount <0, and the filter difference> 0. When the amount |> the determination value, the change amount <0, and the filter difference <0, it is determined that the vehicle is in a deceleration state .

  As described above, according to the present invention, in a construction machine having an arm, an electric motor is used as power for moving the arm, and an acceleration of the arm operating speed to be realized is achieved in a system that uses an inverter to drive the electric motor. The response speed of the state and the deceleration state can be adjusted separately, which has the effect of greatly improving workability and safety, and the inverter can be used even when suddenly decelerating from sudden acceleration with a speed command in operation. The speed command to suppress the rapid change and realize a smooth operation. As a result, the force applied to the arm is reduced, and vibration and noise can be reduced.

  The invention of the present application is a system that drives and controls the operation of the arm with an electric motor and an inverter. They are adjusted separately. Hereinafter, it explains in full detail based on an Example.

  FIG. 1 is a block diagram showing an embodiment of the present invention in the turning direction. Reference numeral 1 denotes an arm operating lever which sets two conditions of a turning direction and a speed command. An acceleration / deceleration determination processing unit 2 receives a signal from the operation lever 1 and determines whether it is an acceleration state command or a deceleration state command. Reference numeral 3 denotes a time constant for acceleration state time constant and a time constant selection unit for deceleration state. The time constant for each time is stored. Based on a command from the acceleration / deceleration judgment processing unit 2, either time constant is selected. Set the constant of the filter part. The constant setting of the filter unit is performed by a constant setting unit 8 composed of 2 and 3. Reference numeral 5 denotes an inverter control unit which controls the inverter 7 by the output of the turning direction and speed instruction sent from the filter unit 4. Reference numeral 6 denotes an arm driving motor which is driven by an inverter 7. The inverter 7 is composed of 2 to 5 components. The operation of the apparatus configured as described above will be described.

  Whether the arm speed command is in the acceleration state or the deceleration state is determined from the amount of change in the command value of the control lever. Therefore, a signal including two conditions of the turning direction from the control lever 1 and the speed command value is periodically sent. In order to sample and extract only the speed command value in the acceleration / deceleration determination processing unit 2, the positive and negative polarities instructing the turning direction are removed by the absolute value calculation, and the change amount is calculated by the equation (1).

Amount of change = | current command value |-| previous command value | (1)
Since the command value issued from the operation lever 1 includes an error because it includes the vibration width generated by the mechanical vibration received by the operation lever itself, it includes an error. Therefore, as the determination value, a value set by Expression (2) about 1.5 to 2 times the vibration width is used.

Judgment value = (noise due to mechanical vibration of the lever) × about 1.5 to 2 (2)
Using this determination value, the acceleration state is determined by equation (3), and the deceleration state is determined by equation (4).
Judgment of acceleration state | change amount |> judgment value and change amount> 0 (3)
Judgment of deceleration state | change amount |> judgment value and change amount <0 (4)
Steady state | Change amount | ≤ Judgment value (5)
In the case of Expression (5), it is determined that the steady state is neither acceleration nor deceleration. FIG. 2 shows a determination flow of the acceleration / deceleration state. After the decision is made by the acceleration / deceleration determination processing unit 2, the time constant for acceleration state 3 and the time constant selection unit for deceleration state are the time constants used at each time, and the time constants used until just before the steady state. And the time constant of the filter unit 4 is set.
The output of the filter unit 4 is input to the control unit 5 of the inverter as a turning direction and a speed signal, so that control capable of separately adjusting the response speed in the acceleration state and the deceleration state can be realized, and workability and safety are improved. . FIG. 3 shows a relationship between the command value of the operating lever and the input / output relationship of the filter unit 4 when the filter is first-order lag and the acceleration time constant is larger than the deceleration time constant.
As apparent from FIG. 3, the response speed of the acceleration state and the deceleration state of the arm operation speed to be realized can be adjusted separately, and the workability and safety are greatly improved.

  FIG. 4 is a block diagram showing another embodiment of the present invention, in which the same or corresponding parts as in FIG. In the case of the first embodiment, the response speed in the steady state of acceleration and deceleration can be executed smoothly. However, as shown in FIG. 3, during the transition from the acceleration state to the deceleration state, the rapid acceleration to sudden deceleration as a speed command. May be emitted. In the second embodiment, the sudden acceleration change is suppressed to further improve the safety.

In FIG. 4, the difference from FIG. 1 is that a calculation unit 9 for obtaining a difference in filter output which is a speed command to the inverter from a speed command signal from the operation lever is added. The operation will be described as an additional condition for switching from the acceleration state to the deceleration state that is output to the determination processing unit.
The timing for switching from the acceleration state to the deceleration state is calculated by the arithmetic unit of 9 using the equation (6), the difference between the speed command value from the operation lever and the filter output that is the speed command value to the inverter (hereinafter referred to as the filter difference) To do.

Filter difference = | command value |-| filter output | (6)
The calculated filter difference is output to the acceleration / deceleration determination processing unit 2. In 2, the filter difference condition is added, the acceleration state is determined by Equation (7), and the deceleration state is determined by Equation (8). In other conditions, it is determined as a steady state.
Determination of acceleration state | Change amount |> Determination value and change amount> 0 and filter difference> 0 (7)
Judgment of deceleration state | change amount |> determination value and change amount <0 and filter difference <0 (8)
As shown in FIG. 5, when the filter difference changes from positive to negative, it is determined that the acceleration state is decelerating, so that there is no significant change in the speed command to the inverter control unit, and thereby smooth switching can be realized. FIG. 6 shows the determination flow of the acceleration / deceleration state. After the decision is made by the acceleration / deceleration determination processing unit 2, the time constant for acceleration state 3 and the time constant selection unit for deceleration state are the time constants used at each time, and the time constants used until just before the steady state. And the time constant of the filter unit 4 is set. The output of the filter is inputted to the control unit 5 of the inverter as a turning direction and a speed signal, so that control capable of separately adjusting the response speed in the acceleration state and the deceleration state can be realized, and workability and safety are improved.
FIG. 7 and FIG. 8 are input / output operation diagrams of an actual filter according to the method of FIG. 6, and the filter output is based on the command value (solid line) and the filter output (dotted line) when the acceleration time constant is 500 ms and the deceleration character constant is 50 ms. When the value catches up with the command value, the time constant is switched, and safer control can be executed.

Configuration diagram showing an embodiment of the present invention Acceleration / deceleration judgment flow chart Filter input / output waveform diagram The block diagram which shows other embodiment of this invention Filter input / output waveform diagram considering filter output Acceleration / deceleration state judgment flow diagram considering filter output Filter operation diagram 1 Filter operation diagram 2 Operation lever actual diagram and input / output relationship diagram Inverter configuration diagram

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Operation lever 2 ... Acceleration / deceleration judgment processing part 3 ... Selection part of time constant for acceleration state, time constant for deceleration state 4 ... Filter part 5 ... Control part 6 ... Motor for arm drive 7 ... Inverter 8 ... Filter time Constant setting unit 9 ... Filter difference calculation unit 10 ... Turning direction command and speed command

Claims (3)

A construction machine having an arm that uses an electric motor as power to move the arm and controls the electric motor, and the control signal of the inverter is the operation amount of the operating lever that operates the arm is input through the filter unit. In
An acceleration / deceleration determination processing unit that inputs an operation amount of the operation lever to determine acceleration / deceleration, a time constant for acceleration state and a time constant for deceleration state are set separately, and the acceleration / deceleration determination processing unit A selection part for acceleration time constant and deceleration time time constant is provided to select the acceleration or deceleration time constant according to the judgment processing signal.
The determination value at the time of acceleration / deceleration determination by the acceleration / deceleration determination processing unit is in a range of 1.5 to 2.0 times the noise due to mechanical vibration of the operation lever, and the amount of change due to the operation of the operation lever is When the absolute value relationship is | change amount |> determination value and change amount> 0, it is determined as an acceleration state, and when | change amount |> determination value and change amount <0, it is determined as a deceleration state. , | Change amount | ≦ determination value, the control device for the motor for driving the arm of the construction equipment is judged as a steady state . 2. The control apparatus for an arm driving motor of a construction equipment according to claim 1, wherein the time constant in the selection unit is set so that a response speed at the time of acceleration is slower than a response speed at the time of deceleration . The difference between the speed command signal by the operation of the operation lever and the output signal of the filter unit is obtained, and this difference is input as a filter difference to the acceleration / deceleration determination processing unit. When the relationship between the absolute values of the amount of change due to the operation is | change amount |> determination value, change amount <0, and the filter difference> 0, the acceleration state is determined, and | change amount |> determination value, change amount 3. The control device for an electric motor for driving an arm of construction equipment according to claim 1, wherein a deceleration state is determined when <0 and the filter difference <0 .

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