JP4881280B2 - Swing control device - Google Patents

Description

  The present invention relates to a turning control device for construction equipment that turns a turning body with an electric motor, and more specifically, relates to a turning control device for construction equipment that controls turning torque based on the state of the turning body.

  Conventionally, a hydraulic drive that operates each mechanism of a construction machine while driving an electric motor with electric energy of a generator driven by an engine that operates at a constant rotational speed, or electric energy of a battery that charges the electric energy of the generator. An apparatus is known (for example, refer to Patent Document 1).

  This hydraulic drive system defines an arm cylinder mechanism and a boom cylinder mechanism as a mechanism that requires excellent operability to smoothly follow the lever operation of the operator, and is directly driven by an engine with variable speed, not an electric motor. These mechanisms are operated by a hydraulic pump.

  On the other hand, this hydraulic drive device defines a bucket cylinder mechanism, a turning mechanism, and a traveling mechanism as mechanisms that do not require excellent operability for smoothly following an operator's lever operation, and these mechanisms are operated by an electric motor. To.

Thus, by distinguishing in advance the mechanism that is operated by the power of the engine and the mechanism that is operated by the power of the electric motor, this hydraulic drive device ensures excellent operability in the arm cylinder mechanism and the boom cylinder mechanism. By using an electric motor when operating other mechanisms, it is possible to increase energy efficiency while reducing engine load.
JP 2001-16704 A

  However, the hydraulic drive device described in Patent Document 1 only distinguishes in advance a mechanism operated by the power of the engine and a mechanism operated by the power of the electric motor, and does not control the operation of a specific electric motor, It cannot cope with the required turning torque that changes depending on the posture of the attachment (referring to a boom, arm, bucket, or the like) and the presence or absence of a load.

  Therefore, the present invention has been made in view of the above points, and an object thereof is to provide a turning control device that improves the turning operability of the turning body.

  According to one aspect of the present invention, there is provided a turning control device for a construction machine that turns a turning body with an electric motor, and detects the state of the turning body by receiving the output of one or more sensors. An operation amount detection unit that receives an output of a lever that controls a turning operation of the revolving body, detects an operation amount of the lever, a state of the revolving body detected by the revolving body state detection unit, and an operation amount detection unit thereof And a controller that outputs a signal for controlling the turning torque to the electric motor based on the detected operation amount.

  In addition, the revolving body state detection unit may detect a turning radius that changes depending on the posture of the attachment of the revolving body as the state of the revolving body.

  The revolving unit state detection unit may detect the boom cylinder pressure as the state of the revolving unit.

  The turning control device further includes an inertia moment deriving unit that derives an inertia moment based on the state of the turning body detected by the turning body state detecting unit, and the controller includes an inertia derived by the inertia moment deriving unit. A signal for controlling the turning torque based on the moment and the operation amount detected by the operation amount detection unit may be output to the electric motor.

  ADVANTAGE OF THE INVENTION According to this invention, the turning control apparatus which improves the turning operability of a turning body can be provided.

  Embodiments of the present invention will be described below.

  FIG. 1 is a diagram showing a configuration example of a hydraulic excavator equipped with a turning control device according to the present invention. In FIG. 1, a hydraulic excavator 10 has an upper swing body 13 mounted on a crawler-type lower traveling body 11 via a swing mechanism 12 so as to be rotatable around a rotation center X.

  The upper swing body 13 includes a cab 14 on the front side portion thereof, and a boom 15, an arm 16 and a bucket 17 in the front center portion, and a boom cylinder 18 and an arm cylinder as actuators for driving these respectively. 19 and a drilling attachment E composed of a bucket cylinder 20 are provided.

  FIG. 2 is a system block diagram of the hydraulic excavator 10. The engine 21, the transmission 22, the generator 23, the battery 24, the hydraulic pump 25, the turning operation lever 26, the turning electric motor 27, the boom operation lever 28, and the control valve 29. A boom pressure sensor 30, a boom angle sensor 31, an arm angle sensor 32, a bucket angle sensor 33, an inverter 34, and a main controller 35.

  The engine 21 drives the generator 23 via the transmission 22 while rotating at a predetermined rotation speed, and drives the hydraulic pump 25 while changing the rotation speed as necessary.

  The transmission 22 is a device for transmitting engine rotation to the generator 23 at a predetermined reduction ratio.

  The generator 23 is a device that obtains electric power by converting mechanical energy into electric energy by electromagnetic action. For example, the electric generator 23 is driven by the engine 21 and the generated electric energy is supplied to a power supply destination (including the turning electric motor 27). The battery 24 is charged with the supplied or generated electric energy.

  The battery 24 is a device that can recover not only the discharge but also the original state before the discharge by charging. Examples of the battery 24 include a lead storage battery, a lithium ion battery, a nickel metal hydride battery, and an electric double layer capacitor.

  The hydraulic pump 25 is a pump for discharging pressure oil, and is driven by the engine 21 to supply pressure oil to the hydraulic actuator including the boom cylinder 18 while changing the discharge amount as necessary.

  The turning operation lever 26 is an operating device for operating the turning of the upper turning body 13, and outputs, for example, a value detected by a potentiometer that is linked to the tilting operation of the lever to the main controller 35 as a lever operation amount.

  The turning electric motor 27 is an electric motor for turning the turning mechanism 12, for example, turning using electric energy supplied from the generator 23 or the battery 24 via the inverter 34 under the control of the main controller 35. The mechanism 12 is turned.

  The boom operation lever 28 is an operation device for operating the boom 15. For example, the boom operation lever 28 switches a remote control valve (not shown) according to the tilting operation of the lever, and the pressure discharged from the auxiliary pump (not shown). The control pressure generated by the oil is transmitted to the control valve 29 as a lever operation amount.

  The control valve 29 is a valve for controlling the hydraulic actuator. For example, the boom cylinder 18 is expanded and contracted by switching the oil path between the hydraulic pump 25 and the boom cylinder 18 according to the control pressure from the boom operation lever 28. Let

  The boom pressure sensor 30 is a sensor for detecting the pressure in the boom cylinder 18. For example, the boom pressure sensor 30 is a sensor using a semiconductor strain gauge, and the pressure in the oil chamber 181 on the side of the boom cylinder 18 that pushes out the rod 180 is measured. To detect.

  The boom angle sensor 31, the arm angle sensor 32, and the bucket angle sensor 33 are, for example, resolver type angle sensors, and detect the inclination angle α of the boom 15, the inclination angle β of the arm 16, or the inclination angle γ of the bucket 17, respectively. To do.

  The inverter 34 is a device for converting DC power into AC power. For example, the inverter 34 converts the DC power of the generator 23 or the battery 24 into AC power based on a control signal output from the main controller 33 and turns the electric motor. 27. The inverter 34 may be integrated with the main controller 33.

  FIG. 3 is a diagram showing the relationship between the inclination angle α of the boom 15, the inclination angle β of the arm 16, the inclination angle γ of the bucket 17, and the turning radius L. FIG. 3A shows the moment of inertia of the excavation attachment E ( For example, the weight of the excavation attachment E × expressed by the turning radius L) is small, and FIG. 3B shows a state in which the moment of inertia of the excavation attachment E is large.

  As shown in FIG. 3A, as the inclination angle α of the boom 15 in the boom foot connecting pin 40 is larger and the inclination angle β of the arm 16 in the arm connecting pin 41 is smaller, the turning radius L becomes smaller. As shown in FIG. 3B, the turning radius L increases as the inclination angle α of the boom 15 decreases and the inclination angle β of the arm 16 increases.

  Note that the turning radius L is, for example, a horizontal distance between the turning center X and the bucket connecting pin 42, but may be a horizontal distance between the turning center X and the tip of the bucket 17. The turning radius increases as the inclination angle γ of the bucket 17 increases, and the turning radius decreases as the inclination angle γ of the bucket 17 decreases.

  The main controller 35 is a device for supplying the electric energy of the electric motor 23 or the battery 24 to various electric motors via the inverter 34. For example, the turning operation lever 26, the boom pressure sensor 30, the boom angle sensor 31, and the arm angle sensor. 32 and the output from the bucket angle sensor 33, the electric energy to be supplied to the turning electric motor 27 is calculated, and the electric energy of the generator 23 or the battery 24 is used for turning while controlling the inverter 34 based on the calculation result. The electric motor 27 is supplied.

  The main controller 35 includes a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and includes, for example, an operation amount detection unit 350, a revolving body state detection unit 351, and the like. While storing a program corresponding to each of the turning torque control units 352 in the ROM, the CPU is caused to execute arithmetic processing corresponding to each unit.

  Next, various control units included in the main controller 35 will be described.

  The operation amount detection unit 350 is a means for detecting the operation amounts of various operation levers. For example, the operation amount detection unit 350 receives the value output from the turning operation lever 26 and operates the operation amount (for example, the operation direction, the operation angle) , Operation speed, etc.).

  Similarly, the operation amount detector 350 may detect an operation amount of a lever for operating the boom cylinder 18, the arm cylinder 19, the bucket cylinder 20, the travel motor, and the like.

  The turning body state detection unit 351 is a means for detecting the state of the turning body turning on the turning mechanism 12. For example, the tilt angle α of the boom 15 output from the boom angle sensor 31 and the arm angle sensor 32 output. The state of the excavation attachment E is detected based on the tilt angle β of the arm to be operated.

  Note that the swing body state detection unit 351 may consider the inclination angle γ of the bucket 17 output by the bucket angle sensor 33 in order to detect the state of the excavation attachment E. This is for more accurately detecting the state of the excavation attachment E.

  The state of the excavation attachment E includes posture, weight, turning radius, and the like, and the turning body state detection unit 351 uses the moment of inertia of the excavation attachment E (turning radius × weight) as an index indicating the state of the excavation attachment E May be derived.

  In this case, the turning radius of the excavation attachment E is derived from, for example, the inclination angles α and β, and the weight of the excavation attachment E may be a known standard weight when the bucket 17 is not loaded. The weight obtained by adding the weight of the load in the bucket 17 estimated based on the boom cylinder pressure output from the boom pressure sensor 30 to the standard weight may be used.

  Since the boom cylinder pressure corresponding to the turning radius (hereinafter referred to as “standard boom cylinder pressure”) in a state where the bucket 17 is not loaded is known, the turning body state detection unit 351 performs arbitrary turning. This is because the weight of the load in the bucket 17 can be estimated based on the difference between the standard boom cylinder pressure at the radius and the actual boom cylinder pressure output from the boom pressure sensor 30.

  Further, the revolving body state detection unit 351 includes a radio wave transmitter (receiver) attached in the vicinity of the bucket connecting pin 42 and a radio wave receiver (transmitter) attached in the vicinity of the turning center X. The turning radius L may be derived using a distance sensor that measures the distance between two points, and the state of the excavation attachment E may be detected.

  Furthermore, the swing body state detection unit 351 measures the cylinder lengths of the boom cylinder 18 and the arm cylinder 19 using a linear position sensor or the like, and detects the state of the excavation attachment E based on the measured cylinder lengths. May be.

  The swing body state detection unit 351 may detect the state of the excavation attachment E based on any other combination of sensor outputs. For example, the boom pressure sensor 30 and the arm pressure sensor (for example, the arm cylinder 19). The state of the excavation attachment E may be detected based on the output of the oil chamber on the side into which the rod is drawn. The output of the boom pressure sensor 30 and the output of the boom angle sensor 31 may be detected. Alternatively, the state of the excavation attachment E may be detected based only on the output of the boom pressure sensor 30.

  As described above, the swirling body state detection unit 351 can detect the state of the excavation attachment E with higher accuracy as the number of sensors to be used increases. It can be detected at low cost.

  The turning torque control unit 352 is means for controlling the turning torque in the turning electric motor 27. For example, the electric power supplied to the turning electric motor 27 based on the state of the excavation attachment E detected by the turning body state detecting unit 351. Increase or decrease energy.

  FIG. 4 is a graph showing an example of the relationship between the turning radius (vertical axis) and the boom cylinder pressure (horizontal axis), and shows that the boom cylinder pressure increases as the turning radius increases. The boom cylinder pressure increases as the moment of inertia increases by multiplying the weight of the excavation attachment E including the weight of the load in the bucket 17 by the distance between the center of gravity of the excavation attachment E and the boom foot connecting pin 40. This is because the distance and thus the moment of inertia increase as the turning radius increases.

  Also, in FIG. 4, when there is no load in the bucket 17, the boom pressure sensor 30 outputs while using the known relationship (see the thick line in FIG. 4) due to the known weight of the excavation attachment E. The turning radius can be derived on the basis of the boom cylinder pressure, and conversely derived from the outputs of the boom angle sensor 31 and the arm angle sensor 32, or the outputs of the boom angle sensor 31, the arm angle sensor 32, and the bucket angle sensor 33. It shows that the boom cylinder pressure can be derived based on the turning radius.

  FIG. 4 shows that the weight of the load in the bucket 17 can be uniquely derived when both the turning radius and the boom cylinder pressure are specified.

  4 shows “load (no)” (refers to a state where there is no load in the bucket 17), “load (light)” (refers to a state where the load in the bucket 17 is light), and “load”. (Heavy) ”(which means that the load in the bucket 17 is heavy) is shown as a representative, but it is assumed that there are more stages between these line segments. The same applies to FIGS. 5 and 6 described later.

  FIG. 5 shows the relationship between the turning radius (vertical axis) and the turning torque (horizontal axis) required to turn the excavation attachment E having the turning radius at a predetermined angular velocity (for example, 60 ° per second). FIG. 6 is a graph showing an example in which the required turning torque (hereinafter referred to as “required turning torque”) increases as the turning radius increases. This is because the required turning torque increases as the moment of inertia increases, like the boom cylinder pressure.

  Further, FIG. 5 shows that, if there is no load in the bucket 17, it is necessary based on the turning radius while using the known relationship (see the thick line in FIG. 5) due to the known weight of the excavation attachment E. It shows that the turning torque can be derived.

  FIG. 5 shows that the required turning torque can be uniquely derived when both the turning radius and the weight of the load in the bucket 17 are specified.

  FIG. 6 shows the relationship between the boom cylinder pressure (vertical axis) and the turning torque (horizontal axis) necessary for turning the excavation attachment E having the boom cylinder pressure at a predetermined angular velocity (for example, 60 ° per second). It is a graph which shows an example of this relationship, and shows that a required turning torque increases as boom cylinder pressure increases.

  FIG. 6 is a relationship derived from the relationship shown in FIGS. 4 and 5. If there is no load in the bucket 17, the known relationship (the weight of the excavation attachment E is known) ( FIG. 6 shows that the required turning torque can be derived based on the boom cylinder pressure.

  FIG. 6 also shows that the required turning torque can be uniquely derived when both the boom cylinder pressure and the weight of the load in the bucket 17 are specified.

  Furthermore, FIG. 6 shows that the increase rate of the required turning torque increases as the weight of the load in the bucket 17 increases. This is because even if the posture of the excavation attachment E is the same, the larger the weight of the load in the bucket 17 is, the larger the center of gravity of the excavation attachment E moves closer to the bucket 17 (outside in the turning radius direction). This is because the moment of inertia becomes larger than when the load in 17 is not heavy or small.

  FIG. 7 is a graph showing an example of the relationship between the moment of inertia (vertical axis) of the excavation attachment E and the turning torque (horizontal axis) necessary for turning the excavation attachment E having the moment of inertia at a predetermined angular velocity, It shows that the required turning torque increases as the moment of inertia increases.

  7 shows the case where the moment of inertia is specified (for example, based on the boom cylinder pressure and the inclination angle α of the boom 15 at the boom foot connection pin 40 and the inclination angle β of the arm 16 at the arm connection pin 41). The weight of the excavation attachment E including the weight of the load and the turning radius are specified.), It shows that the required turning torque can be uniquely derived.

  FIG. 8 is a graph showing an example of the relationship between the lever operation amount (horizontal axis) of the turning operation lever 26 and the change pattern of the turning torque (vertical axis) corresponding to the lever operation amount. If the required turning torque (corresponding to the flat portion of the line segment in FIG. 8) is determined based on the relationship, the change pattern of the turning torque corresponding to the lever operation amount is uniquely determined.

  FIG. 8 shows the lever operation when a relatively small moment of inertia M1 is derived based on the inclination angle α of the boom 15 in the boom foot connection pin 40, the inclination angle β of the arm 16 in the arm connection pin 41, and the boom cylinder pressure. When the amount reaches the predetermined amount A, the turning torque T0 is generated. When the lever operation amount changes from the predetermined amount A to the predetermined amount B, the turning torque is gradually increased, and the lever operation amount becomes the predetermined amount B. It shows that the required turning torque T1 is generated at the time of turning, and the turning torque is maintained at the required turning torque T1 when the lever operation amount exceeds the predetermined amount B.

  Further, FIG. 8 shows that when a relatively large moment of inertia M2 is derived, the turning torque T0 is generated when the lever operation amount reaches the predetermined amount A, and the lever operation amount changes from the predetermined amount A to the predetermined amount B. The required turning torque T2 is generated when the lever operation amount reaches the predetermined amount B while the turning torque is gradually increased, and the turning torque is converted into the required turning torque when the lever operation amount exceeds the predetermined amount B. It shows that it is maintained at T2.

  Similarly, FIG. 8 shows that when an inertia moment intermediate between the inertia moment M1 and the inertia moment M2 is derived, the turning torque T0 is generated when the lever operation amount reaches the predetermined amount A, and the lever operation is performed. While the turning torque is gradually increased when the amount changes from the predetermined amount A to the predetermined amount B, the required turning torque corresponding to each moment of inertia is generated when the lever operation amount reaches the predetermined amount B, and the lever operation It shows that the turning torque is maintained at the required turning torque even when the amount exceeds the predetermined amount B.

  FIG. 8 shows that when the lever operation amount is between the predetermined amount A and the predetermined amount B, a turning torque less than the required turning torque commensurate with the moment of inertia of the excavation attachment E is generated. The manipulated variable is effective when the excavation attachment E is desired to be turned slowly at an angular velocity smaller than a predetermined angular velocity (for example, 60 ° per second) (referred to as inching).

  FIG. 8 also shows that the required turning torque is maintained even when the lever operation amount exceeds the predetermined amount B, which restricts the angular velocity of the excavation attachment E from exceeding the predetermined angular velocity. means.

  FIG. 8 shows that no turning torque is generated when the lever operation amount is less than the predetermined amount A. This is to provide play for the turning operation lever 26.

  FIG. 8 shows line segments corresponding to the two stages of moments of inertia, but it is assumed that there are actually more stages of line segments. In FIG. 8, the moment of inertia is used as an index for distinguishing the many stages. However, the turning radius or the boom cylinder pressure may be used as the index instead of the moment of inertia.

  The method up to determining the turning torque corresponding to the operation lever has been described with reference to FIGS. 4 to 8, but the relationships shown in FIGS. 4 to 8 are stored in the ROM or the like of the main controller 35 as a control map. Further, the proportional relationship (linear relationship) in FIGS. 4 to 8 may be a relationship represented by a non-linear line such as a quadratic curve.

  Next, a process in which the main controller 35 controls the turning torque in the turning electric motor 27 (hereinafter referred to as “turning torque control process”) will be described with reference to FIG. 9. FIG. 9 is a flowchart showing the flow of the turning torque control process.

  First, the swing body state detection unit 351 is configured such that the boom angle sensor 31 outputs the boom 15 tilt angle α, the arm angle sensor 32 outputs the arm 16 tilt angle β, and the boom pressure sensor 30 outputs the boom cylinder. A pressure is acquired (step S1).

  The swing body state detection unit 351 does not consider the inclination angle γ of the bucket 17 output by the bucket angle sensor 33 in order to easily detect the state of the upper swing body 13, but the bucket angle sensor 33 outputs The state of the upper swing body 13 may be detected in more detail in consideration of the inclination angle γ of the bucket 17 to be performed.

  Thereafter, the revolving unit state detection unit 351 refers to the control map stored in the ROM, based on the turning radius derived from the inclination angles α and β and the boom cylinder pressure output from the boom pressure sensor 30. By estimating the weight of the load inside (see FIG. 4), the state of the excavation attachment E is detected (step S2).

  Thereafter, the turning torque control unit 352 is based on the estimated load weight and turning radius (see FIG. 5), or based on the estimated load weight and boom cylinder pressure (see FIG. 6). The required turning torque corresponding to the state of the excavation attachment E is acquired (step S3).

  The turning torque control unit 352 refers to the control map stored in the ROM, and based on the moment of inertia derived from the inclination angles α and β and the boom cylinder pressure (see FIG. 7), the excavation attachment E You may make it acquire the required turning torque corresponding to this state.

  Thereafter, the turning torque control unit 352 acquires a turning torque change pattern (see FIG. 8) corresponding to the required turning torque (step S4), and the operation amount detection unit 350 detects the change pattern while referring to the change pattern. In order to realize the turning torque corresponding to the operation amount of the turning operation lever 26, electric energy is supplied from the generator 23 or the battery 24 to the turning electric motor 27 via the inverter 34 (step S5).

  With the above configuration, the hydraulic excavator 10 controls the turning torque in accordance with the state of the upper turning body 13, thereby hunting in turning when the moment of inertia is small (the turning radius is small) (turning because the turning angular velocity is large). The turning operability can be improved, for example, by smoothing the turning when the moment of inertia is large (the turning radius is large).

  Further, the excavator 10 can further improve the turning operability by controlling the turning torque in consideration of the presence of the load in the bucket 17 in addition to the posture of the upper turning body 13.

  Further, since the excavator 10 generates a turning torque less than the required turning torque when the lever operation amount is small (see between A and B in FIG. 8), the inching that slightly turns the excavation attachment E is performed. The turning operability in the operation can be improved.

  Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and changes are within the scope of the gist of the present invention described in the claims. It can be changed.

  For example, in the above-described embodiment, the excavator 10 controls the turning torque while detecting the attitude of the excavation attachment E and the state of the load in the bucket 17 based on the inclination angles α and β and the boom cylinder pressure. The turning torque may be controlled while detecting the attitude of the excavation attachment E based only on the angles α and β, or the turning torque may be controlled while detecting the attitude of the excavation attachment E based only on the boom cylinder pressure. It may be.

  Although the accuracy of detecting the attitude of the excavation attachment E decreases as the information to be referred to decreases, it is still possible to acquire information necessary and sufficient for controlling the turning torque to improve the turning operability of the upper turning body 13. This is because the turning torque can be controlled more easily and more quickly.

  In the above-described embodiment, the excavator 10 includes the excavation attachment E including the boom 15, the arm 16, and the bucket 17, but includes a magnet, a grapple, a clamp arm, a fork, and the like instead of the bucket 17. You may make it provide another attachment.

It is a figure showing an example of composition of a hydraulic excavator carrying a turning control device concerning the present invention. FIG. 2 is a system block diagram of the hydraulic excavator in FIG. 1. It is a figure which shows the relationship between the inclination angle of a boom, the inclination angle of an arm, and a turning radius. It is a graph which shows an example of the relationship between a turning radius and boom cylinder pressure. It is a graph which shows an example of the relationship between a turning radius and a required turning torque. It is a graph which shows an example of the relationship between boom cylinder pressure and required turning torque. It is a graph which shows an example of the relationship between an inertia moment and a required turning torque. It is a graph which shows an example of the relationship between the lever operation amount and the change pattern of the turning torque corresponding to the lever operation amount. It is a flowchart which shows the flow of a turning torque control process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydraulic excavator, 11 Lower traveling body, 12 Turning mechanism, 13 Upper turning body, 14 Cab, 15 Boom, 16 Arm, 17 Bucket, 18 Boom cylinder, 19 Arm cylinder, 20 Bucket cylinder, 21 Engine, 22 Transmission, 23 Generator, 24 Battery, 25 Hydraulic pump, 26 Turning operation lever, 27 Turning electric motor, 28 Boom operation lever, 29 Control valve, 30 Boom pressure sensor, 31 Boom angle sensor, 32 Arm angle sensor, 33 Bucket angle sensor, 34 Inverter, 35 Main controller, 40 Boom foot connecting pin, 41 Arm connecting pin, 42 Bucket connecting pin, 180 rod, 181 Oil chamber, 350 Operating amount detection unit, 351 rotation Body state detection unit, 352 turning torque control unit, L turning radius, X turning center, alpha, beta tilt angle

Claims (3)

A turning control device for a construction machine that turns a turning body with an electric motor driven by electric energy supplied from an inverter ,
A turning body state detection unit that receives an output of one or more sensors and detects a turning radius that changes according to the posture of the attachment of the turning body as a state of the turning body;
An operation amount detector that receives an output of a lever that controls a turning operation of the revolving body and detects an operation amount of the lever;
A controller that outputs a signal for controlling the turning torque to the electric motor based on the state of the turning body detected by the turning body state detection unit and the operation amount detected by the operation amount detection unit;
The controller controls the turning torque to be increased by increasing the electric energy from the inverter to the electric motor as the turning radius detected by the turning body state detection unit is increased.
A turning control device characterized by that. The revolving unit state detection unit further detects boom cylinder pressure as the state of the revolving unit,
The controller controls the turning torque to increase as the boom cylinder pressure detected by the turning body state detection unit increases.
The turning control device according to claim 1. An inertia moment deriving unit for deriving the inertia moment of the swivel body based on the state of the swivel body detected by the revolving body state detection unit;
The controller outputs a signal for controlling a turning torque to the electric motor based on the inertia moment derived by the inertia moment deriving unit and the operation amount detected by the operation amount detection unit;
The turning control device according to claim 1 or 2.

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