JP2003328398A - Swing controller for work machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable swing torque control in pressing work to improve operability. <P>SOLUTION: In a shovel with an electric motor as a swing drive source, the torque control according to a lever operation amount S is executed instead of feedback speed control according to the operation amount S of an operation lever in the pressing work wherein a bucket of an excavation attachment is pressed to a work target. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing control device for a working machine such as a hydraulic excavator or a crane that swings and drives a swing structure by an electric motor.

[0002]

2. Description of the Related Art A shovel will be described as an example.

As shown in FIG. 9, the shovel has an upper revolving structure 2 mounted on a crawler type lower traveling structure 1 so as to be rotatable about a vertical axis O. The upper revolving structure 2 includes a boom 3 and an arm 4. , Bucket 5 and boom, arm, and bucket cylinders 6, 7, 8
Is installed and configured.

In this shovel, recently, a method of using an electric motor as a drive source instead of or in addition to the conventional hydraulic drive has been proposed, and a method of using an electric motor as a drive source of a revolving structure has also been proposed. (For example, JP 20
01-10783).

When the electric motor is used as the turning drive source as described above, feedback speed control is usually performed to control the speed of the electric motor based on the difference between the target value and the actual value of the turning speed according to the operation amount of the operating means. It will be.

[0006]

However, according to the turning control system using only this feedback speed control, the following problems occur.

FIG. 10 shows a free-turning state in which the upper-part turning body 2 is normally turned on the ground. During normal work for performing the free-turning, the feedback speed control system controls the turning speed according to the operation amount of the operating means. Since it can be performed, there is no operational problem.

On the other hand, as shown in FIG. 11, the side surface of the bucket 5 is pressed against the wall surface 9a of the groove 9 in the direction of the arrow, and the wall surface 9a is pressed.
During the pressing work to excavate and form
Therefore, in the feedback speed control, the deviation between the target value and the actual value of the turning speed becomes large, and the turning action maximizes the turning torque (motor torque) with a small amount of operation.

For this reason, the torque control by the operator becomes impossible during the pressing work by such turning, and the operability is impaired.

Therefore, the present invention provides a turning control device for a working machine capable of controlling turning torque during pressing work in an electric motor drive system and improving operability.

[0011]

According to a first aspect of the present invention, there is provided an electric motor for turning a revolving structure, an operating means for issuing a turning command, and a control means for controlling the electric motor based on the turning command from the operating means. And a turning speed detecting means for detecting a turning speed, wherein the control means performs speed control according to an operation amount of the operating means, wherein the control means includes the turning body. In the pressing work of pressing a part of the above against the work target, instead of the speed control, torque control according to the operation amount of the operation means is performed.

According to a second aspect of the present invention, an electric motor for driving the revolving structure to rotate, operating means for issuing a turning command, control means for controlling the electric motor based on the turning command from the operating means, and a turning speed are detected. And a turning speed detecting means for
In the turning control device for a working machine, which controls the speed according to the operation amount of the operating means by the control means, the control means controls the speed during the pressing operation of pressing a part of the revolving structure against a work target. It is configured to perform control with torque limitation according to the operation amount of the operation means.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the control means sets the actual value of the turning speed to be 0 or close to it in a state where the operation amount of the operating means is larger than the turning movement start position. It is configured to judge the pressing work state when the value is less than or equal to the value.

According to a fourth aspect of the present invention, an electric motor for turning the revolving structure, an operating means for issuing a turning command, a control means for controlling the electric motor based on the turning command from the operating means, and a turning speed are detected. And a turning speed detecting means for
In the turning control device for a working machine, which performs speed control according to the operation amount of the operating means by the control means, the control means is such that the actual value of the turning speed is less than a target value according to the operation amount of the operating means. When the speed is small, the speed control is controlled by adding a torque limit.

According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, the target torque is set to a value greater than 0 when the operating means is in the turning movement start position. It is a thing.

According to the structure of claims 1 to 3, during the pressing work, the torque control according to the operation amount is performed instead of the speed control according to the operation amount of the operating means (claim 1), or the speed control is performed. Control with torque limitation is performed (claim 2).

On the other hand, according to the structure of claim 4, when the actual value of the turning speed is smaller than the target value, the speed control with torque limitation is performed. Therefore, during the pressing work that meets the above conditions, the speed control with torque limitation is performed as in the second aspect.

That is, with any of the configurations, since the turning torque can be controlled according to the operation amount of the operating means during the pressing work, the operability during the pressing work is improved.

In this case, according to the structure of claim 3, in the structure of claim 1 or 2, although the operation amount of the operating means is larger than the turning movement start position (the turning command is issued). When the revolving structure is not revolving, the control means determines that the work is a pressing operation and automatically switches to torque control or speed control with torque limitation.

According to the fourth aspect of the invention, the speed control with torque limitation is automatically performed due to the difference between the target value and the actual value of the turning speed.

For this reason, full-automatic control becomes possible, as compared with a system in which an operator operates a control changeover switch during pressing work, for example.

Further, according to the structure of claim 4, when the actual value of the turning speed is smaller than the target value at the time of acceleration in the free turning, the speed control with torque limitation is performed, so that the acceleration is restricted. . Therefore, shock during acceleration is reduced, and operability is improved in this respect as well.

In addition, since the torque limit does not work during deceleration, deceleration with the maximum torque is possible and emergency stop is possible.

By the way, when the operating means is operated slightly larger than the starting position of the turning movement from the turning stopped state, the actual value of the speed is smaller than the target value (0 due to the inertia of the turning body).
Or a value close to this), the torque control works in claim 1 and the speed control with torque limitation works in claims 2 and 4 even in the free turning state.

In this case, according to the structure of claim 5, the target torque (the target value of the torque in the torque control method, the torque limit value in the speed control method with torque limitation) is obtained when the operating means is in the turning start position. Is set to a value larger than 0, the turning torque immediately acts when the operating means is operated slightly larger than the position where the turning movement starts as described above, the turning rise is quick and the speed control is quickly switched. Replace Therefore, the operability at the beginning of movement is good.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

First Embodiment (Refer to FIGS. 1 to 6) FIG. 1 shows an overall configuration diagram of a turning control device according to this embodiment.

In the figure, reference numeral 11 denotes an operation lever as an operation means, and the operation direction and operation amount of the operation lever 11 are converted into an electric signal by a signal converter 12 and input to a controller 13 which is a control means.

14 is an engine, 15 is this engine 14
In the generator driven by the electric power from the generator 15, both inverters 16 and 17 for the generator and the swing motor are provided.
Is sent to the turning electric motor 18 via
Is transmitted to the upper revolving superstructure 2 via the reduction gear 19, and the revolving superstructure 2 revolves around the vertical axis O in FIGS. 9 to 11.

Reference numeral 20 is an encoder as a turning speed detecting means for detecting the turning speed of the turning electric motor 18, and the electric motor turning speed detected by the encoder 20 is inputted to the controller 13 as an actual value of the turning speed.

As the power source of the swing electric motor 18, a battery 21 and a capacitor 22 are provided in addition to the generator 15, and these power sources are appropriately selected or combined and used. Alternatively, instead of these internal power supplies, power may be supplied from an external power supply. Reference numeral 23 is a battery inverter, and 24 is a capacitor inverter.

A hydraulic pump 26 is provided as a hydraulic power source of a hydraulic actuator circuit 25 for driving the hydraulic actuators of the cylinders 6, 7, 8 etc. of the excavation attachment A, and the hydraulic pump 26 is driven by a pump electric motor 27. It 28 is an inverter for the same electric motor.

The controller 13 controls the speed of the turning electric motor 18 by the speed PID feedback control shown in FIG. 2 during the free turning shown in FIG.

That is, the operation amount S of the operation lever 11 is transmitted as an operation amount signal via the signal converter 12 to the controller 1
3, the lever operation amount S is input by the controller 13
The target value ωref of the turning speed corresponding to is calculated.

This target value ωref and the actual value ωs of the turning speed detected by the encoder 20 are compared to obtain the deviation, and a signal in the direction of making the deviation (ωref-ωs) 0 by PID feedback control is obtained. It is sent to the electric motor 18 via the electric motor inverter 17.

As a result, as shown in FIG. 3, the upper swing body 2 swings at a speed corresponding to the lever operation amount S. Figure 3
Inside, Sc is a lever position where the revolving unit 2 starts to move.

In FIG. 2, for convenience, the output of the encoder 20 is represented as the actual value ωs of the turning speed, but in reality, the motor rotation speed is detected by the encoder 20, and this is divided by the speed reduction ratio of the speed reducer 19. Thus, the turning speed ωs is obtained.

On the other hand, torque control is performed during the pressing work shown in FIG.

That is, first, as a procedure for determining whether or not it is a pressing operation, the controller 13 compares the lever operation amount S with the turning movement start position Sc for each control cycle b as shown in FIG. 4 (step S1). , S2), the actual value ωS of the turning speed is compared with the threshold value ωe shown in FIG. 3 which is preset as a minute value close to 0 (step S3), and the lever operation amount S is set to the movement start position S.
When it is larger than c and the actual value ωs of the turning speed is smaller than the threshold value ωe (YES in both steps S2 and S3), it is determined that the pressing work is performed and the torque control is automatically performed. After switching (step S4), the control cycle b is updated in step S5, and the process returns to step S1.
In addition, in step S2 or step S3, NO (S <S
In the case of c or ωS> ωe), it is considered as a free turn, and Figs.
Feedback speed control is performed (step S
6).

When the object to be pressed has unevenness or is a soft object, the turning speed may be 0 or more, and the judgment of the pressing work may not be stable and hunting may occur. In such a case, it is desirable to reduce the feedback gain of the speed control or to provide a hunting suppressing means for giving a time lag for switching the above determination.

In the torque control, as shown in FIGS. 5 and 6, from the operation amount-torque map 29 in which the relationship between the lever operation amount S and the torque target value τref is set, the torque target value ref is obtained.
Is calculated, this is converted into the current target value iref, and torque PID feedback control is performed.

In this way, the pressing work is automatically judged and switched to the torque control. By this torque control,
Since the electric motor torque corresponding to the lever operation amount S is obtained as shown in FIG. 6, the pressing torque can be controlled according to the operator's intention (lever operation amount).

By the way, according to this control method, when the lever 11 is moved slightly deeper than the starting position Sc of FIG. 6 from the state where the lever is neutral and the turning speed is 0, the speed is 0 due to the inertia of the turning body 2. The torque control is automatically started even in the free turning state of FIG.

Here, in this apparatus, as shown in FIG. 6, the target torque value τref at the starting position Sc is set to a large value τc larger than zero.

In this way, the turning torque τc works at the starting position Sc, and when the lever 11 is inserted slightly deeper than the starting position Sc as described above, the turning operation is immediately started, so that the actual speed value ωs. Quickly reaches the target value ωref and switches to speed feedback control. Therefore, the speed controllability at the beginning of movement can be improved.

Second Embodiment (See FIG. 7) Only differences from the first embodiment will be described.

In the second embodiment, similarly to the first embodiment, the speed feedback control according to the flow of FIG. 5 is performed at the time of free turning, and at the time of pressing work, the speed feedback control is preset to the speed feedback control as shown in FIG. Based on the operation amount-torque limit value map 30, control (torque-limited speed control) is performed with a torque limit according to the lever operation amount S.

Τlim shown on the vertical axis of the map 30 of FIG. 7 is a torque limit value.

As described above, since the speed control with torque limitation is performed during the pressing work, the motor torque corresponding to the lever operation amount can be obtained as in the case of the torque control of FIGS. As in the case of the form, the operability during the pressing work becomes good.

In the second embodiment and the following third embodiment, the torque limit value τlim at the starting position Sc is set to a value τc larger than 0, so that the first embodiment is different from the first embodiment. Similarly, the speed controllability at the start of movement can be improved.

Third Embodiment (see FIG. 8) In the third embodiment, as shown in FIG. 8, when the actual value ωs of the speed is smaller than the target value ωref, it is determined that the vehicle is in a so-called powering state, and this powering is performed. In this state, the speed feedback control is switched to the speed feedback control with torque limitation.

More specifically, the target speed value ωref and the actual speed value ωs are compared for each control cycle b (steps S1, S
2) When ωref ≦ ωs, normal speed feedback control is performed (step S3).

On the other hand, ωref> ωs (YE in step S2)
S), it is determined that the vehicle is in the power running state, and the speed control with torque limitation of the second embodiment (FIG. 7) is automatically switched (step S4), the control cycle b is updated in step S5, and the process proceeds to step S1. Return.

Therefore, during the pressing work which is a kind of power running state, the electric motor torque is controlled by the torque limiting action as in the second embodiment.

Further, according to this control method, even during acceleration in free turning, the speed control action with torque limitation works when the actual value ωs of the turning speed is smaller than the target value ωref, so the acceleration is restricted. Shock during acceleration is reduced.

In addition, since the torque limit does not work during deceleration, deceleration with the maximum torque is possible and emergency stop is possible.

Therefore, the operability is also good in this respect.

By the way, in both the first and second embodiments, the pressing method is automatically judged to switch the control method. However, the operator operates the changeover switch during the pressing operation to switch the control method. You may do it.

The present invention is not limited to excavators, but can be widely applied to revolving work machines such as deep-hole excavators and crushers having excavators as a base, and cranes.

[0060]

As described above, according to the present invention, during the pressing work, the torque control according to the operation amount is performed instead of the speed control according to the operation amount of the operating means (Claim 1), or the speed control. Since the control with torque limitation is performed (claims 2 and 4), it becomes possible to control the turning torque according to the intention of the operator through the operation of the operation means during the pressing work, and the operability during the pressing work is improved. Can be better.

In this case, according to the inventions of claims 3 and 4,
Since torque control or speed control with torque limitation is automatically switched during pressing work, full-automatic control is possible.

Further, according to the invention of claim 4, when the actual value of the turning speed is smaller than the target value at the time of acceleration in the free turning, the speed control with torque limitation is performed, so that the acceleration is restricted. Shock during acceleration can be reduced.

In addition, since the torque limit does not work during deceleration, deceleration with the maximum torque is possible and emergency stop is possible.

Therefore, also in this respect, the operability is improved.

Further, according to the invention of claim 5, since the target torque is set to a value larger than 0 in the state where the operating means is in the turning movement starting position, the operating means is slightly larger than the turning movement starting position. When it is operated, the turning torque is immediately applied, and the turning speed rises quickly and the speed control is swiftly switched. Therefore, the operability at the beginning of movement is good.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a flow of speed feedback control by the device.

FIG. 3 is a diagram showing a relationship between a lever operation amount and a speed target value in the same control.

FIG. 4 is a flowchart for explaining the operation of the device.

FIG. 5 is a diagram showing a flow of torque control by the control.

FIG. 6 is a diagram showing a relationship between a lever operation amount and a torque target value in the same control.

FIG. 7 is a diagram showing a flow of speed control with torque limitation by the control device according to the second embodiment of the present invention.

FIG. 8 is a flowchart for explaining the operation of the control device according to the third embodiment of the present invention.

FIG. 9 is a schematic side view of a shovel that is an application example of the present invention.

FIG. 10 is a front view of the shovel.

FIG. 11 is a front view showing a state in which the bucket of the shovel is pressed against the wall surface of the groove.

[Explanation of symbols]

2 Upper revolving superstructure 11 Operation lever 12 as operation means 12 Signal converter 13 for converting operation of operation lever into electric signal 13 Controller as control means 18 Turning electric motor 20 Encoder 15 as turning speed detection means Power generation as electric power source for electric motor Machine 21 Same battery 22 Same capacitor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Inoue             1-5-5 Takatsukadai, Nishi-ku, Kobe City Stock Association             Company Kobe Steel Works, Kobe Research Institute (72) Inventor Hideaki Yoshimatsu             1-5-5 Takatsukadai, Nishi-ku, Kobe City Stock Association             Company Kobe Steel Works, Kobe Research Institute (72) Inventor Mamoru Uejima             740 Yagi, Okubo-cho, Akashi-shi, Hyogo             Ruco Construction Machinery Co., Ltd. Okubo Factory F-term (reference) 2D003 AA01 AB02 BA01 BB01 CA10                       DA04 DB01 DB03 DC02                 3F205 AA05 EA10 KA10

Claims (5)

[Claims] 1. A motor for driving a revolving structure, an operating means for issuing a turning command, a control means for controlling the electric motor based on a turning command from the operating means, and a turning speed detecting means for detecting a turning speed. In the swing control device for a working machine, wherein the control means controls the speed according to the operation amount of the operating means, the control means is configured to press a part of the swing structure against a work target during a pressing operation. ,
A turning control device for a working machine, which is configured to perform a torque control according to an operation amount of the operating means instead of the speed control. 2. An electric motor for driving a revolving structure to rotate, an operating means for issuing a turning command, a control means for controlling the electric motor based on a turning command from the operating means, and a turning speed detecting means for detecting a turning speed. In the swing control device for a working machine, wherein the control means controls the speed according to the operation amount of the operating means, the control means is configured to press a part of the swing structure against a work target during a pressing operation. ,
A turning control device for a working machine, which is configured to perform a control in which a torque limit is added to the speed control according to an operation amount of an operating means. 3. The actual value of the turning speed is 0 when the operation amount of the operating means is larger than the turning movement starting position.
Alternatively, it is configured to judge the pressing work state when the set value is close to or less than the set value.
Alternatively, the turning control device for the working machine according to the item 2. 4. An electric motor for driving a revolving structure to rotate, an operating means for issuing a turning command, a control means for controlling the electric motor based on a turning command from the operating means, and a turning speed detecting means for detecting a turning speed. In the swing control device for a working machine, wherein the control means controls the speed according to the operation amount of the operating means, the control means is such that the actual value of the swing speed is the operation amount of the operating means. A control device for a working machine, which is configured to perform a control in which a torque limit is added to the speed control when the value is smaller than a corresponding target value. 5. The work according to claim 1, wherein the target torque is configured to have a value larger than 0 in a state where the operating means is in the turning movement start position. Machine turning control device.