JP5062128B2 - Swing drive device for work machine - Google Patents

Description

  The present invention relates to a turning drive device for a work machine that is provided in a work machine such as an excavator or a crane having a turning body and drives the work machine with an electric motor.

  In recent years, as a means for driving a revolving body of a work machine, use of an electric actuator with high energy efficiency has been studied in place of a conventional hydraulic actuator. For example, Patent Document 1 discloses a turning control method in which a target speed is set in accordance with an operation amount of an operation lever, and a target torque of an electric motor is determined using a deviation between the target speed and an actual turning speed. .

  However, in such motor control, the response of the actuator to the lever operation is more sensitive than the hydraulic drive system. For example, if the speed is changed by lever operation in the lever middle region, the electric motor changes rapidly, and as a result, hunting or shock may occur.

In order to eliminate such inconvenience, Patent Document 2 discloses an apparatus for calculating a target turning speed using a virtual hydraulic circuit model. Specifically, in the same document 2, in addition to performing feedback control based on the deviation between the target turning speed and the actual turning speed, the meter-in flow rate, the meter-out flow rate, and the bleed-off flow rate set for the hydraulic circuit model are described. It describes that a time calendar response calculation is performed by a numerical integration method with simultaneous governing equations.
Japanese Patent Laid-Open No. 2001-10783 JP 2003-333876 A

  The control described in Patent Document 2 is based on the conventional general feedback control described in Patent Document 1, that is, control based on the deviation between the target turning speed and the actual turning speed. Since this is only corrected by calculation using the hydraulic circuit model, and the calculation uses only the operation amount of the operation lever as the actual detection value, as in Patent Document 1, the moment of inertia of the revolving structure is used. There is a problem that it is difficult to reflect the change in the turning speed due to the change of. In addition, since it is necessary to solve simultaneous equations composed of a large number of governing equations by a numerical integration method, a program for arithmetic control becomes complicated.

  In view of such circumstances, the present invention is a swing drive control that takes into account the effect of changes in the actual swing speed of the work machine on the hydraulic circuit characteristics with a simple arithmetic operation using a virtual hydraulic circuit model. An object of the present invention is to provide an apparatus capable of performing the above.

  As means for solving the above-mentioned problems, the present invention provides an apparatus for driving a swiveling body provided in a work machine having a swivel body, the electric motor for swiveling the swivel body, and the swivel body A turning speed detecting means for detecting an actual turning speed of the turning body, an operating member operated to designate the turning speed of the turning body, and outputting a command signal corresponding to the operation amount; A hydraulic motor that drives the body, a hydraulic pump that supplies hydraulic oil to the hydraulic motor, and a meter-in flow rate, a meter-out flow rate, and a bleed-off flow rate for the hydraulic motor that change according to the operation amount of the operation member, respectively. A calculation control device that creates and outputs a turn command signal for operating the electric motor with characteristics approximating those of a virtual hydraulic circuit model including a flow control valve The arithmetic control device includes motor pressure assumption means for assuming the inlet pressure and the outlet pressure of the hydraulic motor based on the operation amount of the operation member and the turning speed of the turning body, and the assumed inlet pressure. Command signal generating means for calculating a target torque of the electric motor based on a difference from the outlet pressure and generating the turning command signal based on the target torque is included.

  In this apparatus, a hydraulic circuit model including a hydraulic motor, a hydraulic pump, and a flow rate control valve is adopted, and the inlet pressure and the outlet pressure of the hydraulic motor are set based on the operation amount of the operation member and the swing speed of the swing body. It is assumed that the target torque of the motor is calculated based on the difference between the assumed inlet pressure and outlet pressure, and a turning command signal is created based on this target torque. More accurate control can be performed in consideration of the influence on the circuit characteristics.

  Further, in this apparatus, it is possible to create the turning command signal without performing a complicated calculation operation. Specifically, the motor pressure assumption means includes target flow rate calculation means for calculating a turning target flow rate corresponding to the operation amount of the operating device, meter-in flow rate to the hydraulic motor, meter-out flow rate from the hydraulic motor, and A basic flow rate determining means for determining each bleed-off flow rate, a pump for calculating a discharge pressure of the hydraulic pump based on a turning target flow rate calculated by the target flow rate calculating means and each flow rate determined by the basic flow rate determining means Motor pressure calculation for calculating an inlet pressure and an outlet pressure of the hydraulic motor assumed based on a pressure calculating means, a turning speed detected by the turning speed detecting means, and at least each flow rate determined by the basic flow rate determining means The basic flow rate determining means determines the meter-out flow rate based on the turning target flow rate, the pump pressure calculating means and the front After the motor pressure calculating means calculates the discharge pressure of the hydraulic pump and the inlet pressure of the hydraulic motor, respectively, the meter-in flow rate is determined based on these differential pressures, and the pump pressure calculating means determines the discharge pressure of the hydraulic pump. After calculating, according to what determines the bleed-off flow rate based on the discharge pressure and the operation amount of the operation member, it is possible to change the actual turning speed with a simple calculation control operation without solving a complicated governing equation. The differential pressure of the hydraulic motor can be assumed.

  Further, the arithmetic control device approximates the characteristics of a hydraulic circuit model including relief valves provided on the inlet side and the outlet side of the hydraulic motor in addition to the hydraulic motor, the hydraulic pump, and the flow rate control valve, respectively. And a motor pressure assumption means of the arithmetic and control unit further includes a relief flow rate determination means for determining a relief flow rate by the relief valve, and the motor pressure assumption The motor pressure calculating means is assumed based on the turning speed detected by the turning speed detecting means, at least each flow rate determined by the basic flow rate determining means, and the relief flow rate determined by the relief flow rate determining means. The inlet pressure and outlet pressure of the hydraulic motor are calculated, and the relief flow rate determining means is operated by the motor pressure calculating means. After calculating the inlet pressure and outlet pressure of the hydraulic motor, the relief flow rate of each relief valve is calculated based on the inlet pressure and outlet pressure. In addition to the meter-in flow rate, meter-out flow rate, and bleed-off flow rate, The characteristics approximated by the actual hydraulic circuit characteristics in consideration of the relief flow rate can be realized. .

  Further, the motor pressure assumption means further includes an adjustment flow rate determination means for calculating a response characteristic adjustment flow rate for suppressing torque hunting of the torque of the electric motor based on the turning acceleration of the turning body. The motor pressure calculating means determines the turning speed detected by the turning speed detecting means, each flow rate determined by the basic flow rate determining means, the relief flow rate determined by the relief flow rate determining means, and the adjusted flow rate calculating means. In the calculation of the inlet pressure and the outlet pressure of the hydraulic motor assumed based on the adjusted flow rate, the response characteristic adjusted flow rate calculated from the turning acceleration is added to the flow rate determined by the basic flow rate determining means and the relief flow rate determining means. It is possible to take into account the feedback control element based on the turning acceleration, and the hydraulic circuit with a simple configuration Enhance the stability of the response of Dell, it is possible to effectively suppress hunting.

  As described above, according to the present invention, in addition to using the hydraulic circuit model including the hydraulic motor, the hydraulic pump, and the flow rate control valve, the inlet of the hydraulic motor is based on the operation amount of the operation member and the actual turning speed. Assuming the difference between the pressure and the outlet pressure and calculating the target torque of the motor based on the differential pressure, the influence of the actual turning speed on the hydraulic circuit characteristics is also considered with a simple calculation control operation. There exists an effect which can implement | achieve turning drive control with few torque shocks.

  A preferred embodiment of the present invention will be described with reference to the drawings. In this embodiment, a hydraulic excavator is exemplified as the work machine. However, the work machine to which the present invention is applied is not limited to this, and can be widely applied to cranes and other work machines having various swiveling bodies. Is possible.

  The hydraulic excavator shown in FIG. 1 includes a lower traveling body 1 and an upper swing body 2, and the upper swing body 2 has a rotation shaft R.P. It is mounted on the lower traveling body 1 so as to be able to turn around A.

  The upper swing body 2 includes a front attachment 3. The front attachment 3 includes a boom 3a, a boom cylinder 3b for raising and lowering the boom 3a, an arm 3c and an arm cylinder 3d for rotating the arm 3c, a bucket 3e and a bucket cylinder for rotating the bucket 3e. 3f. The change in the posture of the front attachment 3 changes the moment of inertia of the entire upper swing body 2 and affects the turning speed.

  In addition, the upper swing body 2 includes a cabin 4 disposed on the side of the front attachment 3, an unillustrated engine, a hydraulic device, a tank, and the like disposed behind the cabin 4, and a device cover 5 covering these. .

  The hydraulic excavator further includes a turning drive device 10 for electrically turning the upper swing body 2. As shown in FIG. 2, the turning drive device 10 includes an electric motor 12, a power source 14, an encoder (turning speed detecting means) 16, an operating device 18, and a controller (calculation control device) 20.

  The electric motor 12 turns the upper swing body 2 by receiving power supply from the power source 14, and an output shaft of the electric motor 12 is connected to the upper swing body 2 via a speed reducer 15. The electric motor 12 is composed of an AC servo motor, but a DC servo motor can also be applied.

  The power source 14 is a combination of a generator driven by the engine, a battery for storing electric power generated by the generator, a capacitor, and the like. The power source 14 is not essential for the present invention, and may be one that receives power from the outside of the work machine, for example.

  The encoder 16 detects the amount of rotation of the output shaft of the electric motor 12 and outputs a detection signal thereof. Based on the time differentiation of the output signal of the encoder 16, the turning speed of the upper turning body 2 is detected.

  The operating device 18 is provided in the vicinity of the driver's seat in the cabin 4 and includes an operation lever (operation member) that can be rotated and a potentiometer that detects the operation amount. The operation direction and the operation amount L of the operation lever are associated with the turning direction and the turning speed of the upper swing body 2. The potentiometer outputs an operation signal having a positive / negative sign corresponding to the operation direction and an absolute value corresponding to the operation amount L.

  The controller 20 is composed of a microcomputer or the like, receives output signals from the encoder 16 and the operation device 18, and operates the electric motor with characteristics approximating those of a virtual hydraulic circuit model 50 as shown in FIG. It functions as an arithmetic and control unit that creates and outputs a turn command signal for the purpose.

  In this embodiment, the hydraulic circuit model 50 includes a hydraulic motor 52 capable of rotating forward and reverse to drive the upper swing body 2, a hydraulic pump 54 that supplies hydraulic oil to the hydraulic motor 52, and the hydraulic pressure It is assumed that a control valve (flow rate control valve) 56 interposed between the motor 52 and the hydraulic pump 54 and a pair of relief valves 57 and 58 are included.

  The position of the valve body of the control valve 56 is switched so as to rotate the hydraulic motor 52 in a turning direction corresponding to the operation direction of the operation lever, and the hydraulic pump 54 corresponds to the operation amount L of the operation lever. The valve body is operated so as to change the meter-in flow rate Qmi from the hydraulic pump 52 to the hydraulic motor 52, the meter-out flow rate Qmo from the hydraulic motor 52, and the bleed-off flow rate Qb from the hydraulic pump 54 to the tank. is assumed. In this embodiment, each of the relief valves 57 and 58 is opened when the primary pressure reaches a preset pressure, and in the opened state, the hydraulic oil is relieved at a flow rate proportional to the primary pressure. Assumed to be.

  In addition, assumption of these relief valves 57 and 58 is not essential in the present invention. Further, when the turning direction of the swing body is not specified (that is, when the swing body is driven to swing in only one direction), a relief valve may be assumed only on the inlet side of the hydraulic motor.

  As shown in FIG. 4, the controller 20 includes a motor pressure assumption unit 30 and a command signal generation unit 40. The motor pressure assumption means 30 is based on the operation amount L of the operation lever input from the operation device 18 and the turning speed ω of the upper swing body 2 obtained from a signal input from the encoder 16. Assume an inlet pressure Pmi and an outlet pressure Pmo of the motor 52. The command signal generating means 40 calculates a target torque To of the electric motor based on a difference between an assumed inlet pressure Pmi and an outlet pressure Pmo (motor differential pressure ΔPm = Pmi−Pmo), and based on the target torque To To produce the turning command signal.

  The motor pressure assumption unit 30 includes a target flow rate calculation unit 32, a basic flow rate determination unit 33, a relief flow rate determination unit 34, an adjustment flow rate determination unit 35, a pump pressure calculation unit 36, and a motor pressure calculation unit 38. Including.

  The target flow rate calculation means 32 calculates a turning target flow rate Qo corresponding to the operation amount L of the operation lever. Specifically, the target flow rate calculation means 32 stores a preset relationship of the operation amount L and the turning target flow rate Qo as shown in FIG. 5A, and based on this relationship and the operation amount L. To calculate the turning target flow rate Qo.

  The basic flow rate determining means 33 determines the meter-in flow rate Qmi, the meter-out flow rate Qmo, and the bleed-off flow rate Qb, respectively. Specifically, the basic flow rate determining means 33 sets the turning target flow rate Qo as it is to the meter-out flow rate Qmo, while setting the meter-in flow rate Qmi and the bleed-off flow rate Qb to preset initial values in the initial stage. . Then, after the pump pressure calculation means 36 and the motor pressure calculation means 38 calculate the discharge pressure Pp of the hydraulic pump 54 and the inlet pressure Pmi of the hydraulic motor 52 based on this initial value, respectively, the discharge pressure A meter-in flow rate Qmi is calculated based on the difference between Pp and the inlet pressure Pmi, and a bleed-off flow rate Qb is calculated based on the discharge pressure Pp calculated by the pump pressure calculation means 36 and the operation amount L of the operation lever.

  The relief flow rate determining means 34 determines the relief flow rate at each of the relief valves 57 and 58. Specifically, the relief flow rate of each relief valve 57, 58 is set to an initial value set in advance in the initial state, and after the inlet pressure Pmi and the outlet pressure Pmo of the hydraulic motor 52 are calculated as described above, Based on the inlet pressure Pmo and the outlet pressure Pmi and the turning direction, the relief flow rates of the relief valves 57 and 58 are calculated. Specifically, it is determined whether the relief valves 57 and 58 are on the inlet side or the outlet side based on the turning direction, Qri is the relief flow rate of the relief valve on the inlet side, and the relief flow rate of the relief valve on the outlet side. Is calculated as Qro.

  The adjustment flow rate determining means 35 obtains the turning acceleration β by time differentiation of the turning speed ω of the upper turning body 2 and calculates a response characteristic adjustment flow rate Qaj based on the turning acceleration β. This response characteristic adjustment flow rate Qaj is an adjustment flow rate set to suppress hunting of the output torque of the electric motor 12.

  The pump pressure calculation means 36 is based on the turning target flow rate Qo calculated by the target flow rate calculation means 32 and the flow rates Qmi, Qmo, Qb determined by the basic flow rate determination means 33, and the discharge pressure of the hydraulic pump 54. Pp is calculated.

  The motor pressure calculation means 38 calculates a motor flow rate Qmt, which is a flow rate of hydraulic oil passing through the hydraulic motor 52, based on the turning speed ω, and is designated by the motor flow rate Qmt and the operation direction of the operation lever. Turning direction, the flow rates Qmi, Qmo, Qb determined by the basic flow rate determining means 33, the relief flow rates Qri, Qro determined by the relief flow rate determining means 34, and the adjusted flow rate calculating means 35 Based on the adjusted flow rate Qaj, the assumed inlet pressure Pmi and outlet pressure Pmo of the hydraulic motor 52 are respectively calculated.

Next, the calculation control operation performed by the controller 20 will be described with reference to the characteristic graph shown in FIG. 5 and the flowchart shown in FIG. This arithmetic control operation is repeated every predetermined sampling period (for example, 1 msec).
(1) Capture various information (step S1 in FIG. 6)
The controller 20 takes in the turning operation direction and turning amount L of the operating lever of the operating device 18 and the turning speed ω of the upper turning body 2 detected by the encoder 16. The turning operation amount L is captured as a ratio (%) to the full operation amount.
(2) Calculation of turning target flow rate Qo (step S2)
The target flow rate calculation means 32 of the controller 20 is based on the turning operation amount L and the relationship between the turning operation amount L and the turning target flow rate Qo stored in advance, and the turning target flow rate Qo corresponding to the turning operation amount L. Is calculated. In this embodiment, as shown in FIG. 5A, in this embodiment, the turning target flow rate Qo increases as the operation amount L increases, and the turning target flow rate Qo is 100% in the operation amount L and in the vicinity thereof. The maximum relationship is set.
(3) Determination of basic flow rate and relief flow rate (steps S3, S4, S4 ')
The basic flow rate determining means 33 and the relief flow rate determining means 34 of the controller 20 include a basic flow rate (meter-in flow rate Qmi, meter-out flow rate Qmo and bleed-off flow rate Qb), a relief flow rate Qri on the hydraulic motor inlet side, and a relief flow on the hydraulic motor outlet side. The flow rate Qro is determined. As described above, which of the relief valves 57 and 58 is the inlet side relief valve and which is the outlet side relief valve is determined based on the turning direction specified by the operation direction of the operation lever. .

Among the flow rates, the meter-out flow rate Qmo is determined to be equal to the turning target flow rate Qo or a corrected value (for example, multiplied by an adjustment coefficient). On the other hand, the other flow rates Qmi, Qb, Qri, Qro basically use the discharge pressure Pp of the hydraulic pump 54 and the inlet pressure Pmi and the outlet pressure Pmo of the hydraulic motor 52 calculated as described below. (Step S4). However, in the initial stage before these pressures Pp, Pmi, and Pmo are calculated (YES in step S3), the flow rates Qmi, Qb, Qri, and Qro are set to initial values set in advance for these flow rates. (Step S4 ').
(4) Calculation of response characteristic adjustment flow rate (step S5)
The controller 20 according to this embodiment calculates a response characteristic adjustment flow rate Qaj in addition to the basic flow rates Qmi, Qmo, Qb and the relief flow rates Qri, Qro. This response characteristic adjustment flow rate Qaj is a flow rate introduced for the purpose of correction for suppressing hunting of the output torque of the electric motor 12, and in this embodiment, a preset coefficient Kaj and the turning speed ω Is given by the product of the turning acceleration β (= dω / dt) obtained by time differentiation of.
(5) Calculation of pump discharge pressure and motor pressure (step S6)
The pump pressure calculating means 36 and the motor pressure calculating means 38 calculate the discharge pressure Pp of the hydraulic pump 54 and the inlet pressure Pmi and the outlet pressure Pmo of the hydraulic motor 52 based on the flow rates determined as described above.

  Specifically, in this embodiment, each pressure is calculated using the following equation.

Pp = ∫ [Kp * (Qo−Qmi−Qb)] dt
Pmi = ∫ [Kp * (Qmi−Qmt−Qri−Qaj)] dt
Pmo = ∫ [Kp * (Qmt−Qmo−Qro + Qaj)] dt
In these equations, Kp represents a preset coefficient, and ∫ [Q] dt represents a time integral value of Q within a preset time. Further, the motor passage flow rate (the flow rate of hydraulic oil passing through the hydraulic motor 52) Qmt is calculated by multiplying the turning speed ω by a preset coefficient Kmt.

  The pressures Pp, Pmi, Pmo thus calculated are used for calculating the meter-in flow rate Qmi, the bleed-off flow rate Qb, and the relief flow rates Qri, Qro in the next calculation control operation. Specifically, these flow rates are calculated by the following equation (step S4).

Qmi = Kmi * (Pp−Pmi) (when Pp ≧ Pmi)
Qmi = 0 (when Pp <Pmi)
Qb = Pp * Kb * (100−γ * L)
Qri = Kr * Pmi
Qro = Kr * Pmo
Here, Kmi is a coefficient set in correspondence with the operation amount L. In this embodiment, as shown in FIG. 5B, the micro operation area is set to 0 and exceeds this micro operation area. It is set so as to increase rapidly and maintain a constant value.

  Further, γ is an adjustment coefficient set in advance for the operation amount L, and is appropriately set within a range of γ <1. Kb is a constant coefficient.

Kr is a coefficient set in consideration of the characteristics of the relief valves 57 and 58 that open only when the primary pressure (Pmi or Pmo) of the relief valves 57 and 58 exceeds a set value. Then, as shown in FIG. 5 (c), the motor pressure (Pmi or Pmo) is set to 0 in the region between the preset lower limit pressure Pmin and the upper limit pressure Pmax, and is almost constant in the other regions. Is set.
(6) Creation of turn command signal (steps S7, S8)
The command signal generating means 40 of the controller 20 is configured to use a coefficient Kt preset to a motor differential pressure ΔPm (= Pmi−Pmo) that is a difference between the inlet pressure Pmi and the outlet pressure Pmo of the hydraulic motor 52 calculated as described above. Is calculated as a motor target torque To (step S7), and a turn command signal to be input to the motor 12 to obtain the target torque To is generated and output to the motor 12 (step S7). S8). Thereby, the drive of the upper turning body 2 by the electric motor 12 is controlled.

  In this turning drive device 10, a hydraulic circuit model 50 including a hydraulic motor 52, a hydraulic pump 54, and a control valve 56 that is a flow rate control valve is adopted when creating a turning command signal to be input to the electric motor 12. In addition, the inlet pressure Pmi and the outlet pressure Pmo of the hydraulic motor 52 are assumed based on the operation amount (turning operation amount) L of the operation lever and the turning speed ω of the upper turning body 2, and the motor difference that is the difference between them is assumed. Since the target torque To of the electric motor is calculated based on the pressure ΔPm and a turning command signal is created based on the target torque To, more accurate considering the influence of the actual turning speed change on the hydraulic circuit characteristics High control can be performed.

  Further, in this apparatus, it is possible to create the turning command signal with a simple configuration without performing a complicated calculation operation such as solving a large number of simultaneous governing equations as in the prior art. Specifically, the turning target flow rate Qo calculated by the target flow rate calculation unit 32 of the motor pressure assumption unit 30, the meter-in flow rate Qmi, the meter-out flow rate Qmo, and the bleed-off flow rate Qb determined by the basic flow rate determination unit 33 Based on this, the pump pressure calculation means 36 of the motor pressure assumption means 30 calculates the discharge pressure Pp of the hydraulic pump 54, and the motor pressure calculation means 38 assumes the hydraulic motor 52 based on the turning speed ω and the flow rates. Since the inlet pressure Pmi and the assumed outlet pressure Pmo are calculated, and the basic flow rate determining means 33 calculates the meter-in flow rate Qmi and the bleed-off flow rate Qb anew using the calculated pressures Pp, Pmi, Pmo, it is easy. It is possible to assume the differential pressure of the hydraulic motor in consideration of the actual turning speed change in a simple calculation control operation.

  In particular, in this embodiment, the relief flow rate determining means 34 included in the motor pressure assumption means 30 determines the relief flow rates of the relief valves 57 and 58 included in the hydraulic circuit model 50, and the motor inlet taking this relief flow rate into consideration. Since the calculation of the pressure Pmi and the motor outlet pressure Pmo is performed, characteristics approximate to actual hydraulic circuit characteristics can be realized. .

  Further, in this embodiment, the adjustment flow rate determination means 35 included in the motor pressure assumption means 30 sets the response characteristic adjustment flow rate for suppressing the motor torque hunting based on the turning acceleration β of the upper turning body 2. Since the motor inlet pressure Pmi and the motor outlet pressure Pmo are calculated and the flow rate is taken into account, the stability of the response of the hydraulic circuit model can be improved with a simple configuration, and hunting can be effectively suppressed.

  The simulation results for the examples of the present invention and comparative examples are shown in FIGS. FIG. 7 is a calculation based on changes in the assumed values of the motor inlet pressure and the outlet pressure with respect to lever operation in the comparative example (example in which the hydraulic circuit model 50 shown in FIG. 3 is used but the flow rate is not adjusted). FIG. 8 shows the assumed values of the motor inlet pressure and the outlet pressure, the motor target according to the embodiment of the present invention, and the time variation of the turning speed controlled based on the target torque. The time change of a torque and turning speed is shown.

  In the comparative example shown in FIG. 7, the vibration characteristics of the motor pressure, the target torque, and the turning speed in response to the lever operation are all high, whereas in the embodiment shown in FIG. 8, the flow rate adjustment according to the present invention is performed. As a result, it is understood that all of the motor pressure, the target torque, and the turning speed are smoothed and the vibration components are effectively reduced.

1 is an external view of a hydraulic excavator according to an embodiment of the present invention. It is a block diagram of the turning drive device mounted in the said hydraulic excavator. It is a circuit diagram which shows the hydraulic circuit model used for the calculation control for preparation of the turning command signal in the said turning drive device. It is a block diagram which shows the structure of the controller in the said turning drive device. (A)-(c) is a graph which shows the various characteristics used for the calculation in the said controller. It is a flowchart which shows the calculation control operation | movement of the said controller. It is a graph which shows the response characteristic of the comparative example of this invention. It is a graph which shows the response characteristic of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper turning body 3 Front attachment 10 Turning drive device 12 Electric motor 16 Encoder (turning speed detection means)
18 controller 20 controller (arithmetic controller)
DESCRIPTION OF SYMBOLS 30 Motor pressure assumption means 32 Target flow rate calculation means 33 Basic flow rate determination means 34 Relief flow rate determination means 35 Adjustment flow rate determination means 36 Pump pressure calculation means 38 Motor pressure calculation means 40 Command signal preparation means 50 Hydraulic circuit model 52 Hydraulic motor 54 Hydraulic pump 56 Control valve 57, 58 Relief valve

Claims (4)

A device provided in a work machine having a swivel body for driving the swivel to swivel,
An electric motor for turning the turning body;
A turning speed detecting means for detecting an actual turning speed of the turning body;
An operating device that includes an operating member that is operated to specify the turning speed of the revolving body, and that outputs a command signal corresponding to the operation amount;
A hydraulic motor that drives the swivel body, a hydraulic pump that supplies hydraulic oil to the hydraulic motor, and a meter-in flow rate, a meter-out flow rate, and a bleed-off flow rate for the hydraulic motor corresponding to the operation amount of the operation member. A calculation control device that creates and outputs a turn command signal for operating the electric motor with characteristics approximating the characteristics of a virtual hydraulic circuit model including a flow control valve to be changed,
The arithmetic control device includes motor pressure assumption means for assuming an inlet pressure and an outlet pressure of the hydraulic motor based on an operation amount of the operation member and a turning speed of the turning body, and the assumed inlet pressure and outlet pressure. And a command signal generating means for calculating the target torque of the electric motor based on the difference between the motor and generating the swing command signal based on the target torque. In the turning drive device for the work machine according to claim 1,
The motor pressure assumption means is
Target flow rate calculation means for calculating a turning target flow rate corresponding to the operation amount of the operating device;
Basic flow rate determining means for determining a meter-in flow rate to the hydraulic motor, a meter-out flow rate from the hydraulic motor, and a bleed-off flow rate, respectively;
A pump pressure calculating means for calculating a discharge pressure of the hydraulic pump based on a turning target flow rate calculated by the target flow rate calculating means and each flow rate determined by the basic flow rate determining means;
Motor pressure calculating means for calculating an inlet pressure and an outlet pressure of the hydraulic motor assumed based on the turning speed detected by the turning speed detecting means and at least each flow rate determined by the basic flow rate determining means,
The basic flow rate determining means determines the meter-out flow rate based on the turning target flow rate, and the pump pressure calculating means and the motor pressure calculating means calculate the discharge pressure of the hydraulic pump and the inlet pressure of the hydraulic motor, respectively. After that, the meter-in flow rate is determined based on these differential pressures, and after the pump pressure calculation means calculates the discharge pressure of the hydraulic pump, the bleed-off flow rate is determined based on the discharge pressure and the operation amount of the operation member. A swing drive device for a work machine, characterized in that: In the turning drive device for the work machine according to claim 2,
The arithmetic and control unit has characteristics that approximate the characteristics of a hydraulic circuit model including relief valves provided on an inlet side and an outlet side of the hydraulic motor in addition to the hydraulic motor, the hydraulic pump, and the flow rate control valve, respectively. Creates a turn command signal for operating the motor,
The motor pressure assumption means of the arithmetic control device further includes a relief flow rate determining means for determining a relief flow rate by the relief valve,
The motor pressure calculation means of the motor pressure assumption means is based on the turning speed detected by the turning speed detection means, at least each flow rate determined by the basic flow rate determination means and the relief flow rate determined by the relief flow rate determination means. Calculate the assumed inlet pressure and outlet pressure of the hydraulic motor,
The relief flow rate determining means calculates a relief flow rate of each relief valve based on the inlet pressure and the outlet pressure after the inlet pressure and outlet pressure of the hydraulic motor are calculated by the motor pressure calculating means. A turning drive device for a working machine. In the turning drive device for the work machine according to claim 3,
The motor pressure assumption means of the arithmetic control device further includes an adjustment flow rate determination means for calculating a response characteristic adjustment flow rate for suppressing torque hunting of the electric motor based on the turning acceleration of the turning body,
The motor pressure calculation means of the motor pressure assumption means includes a turning speed detected by the turning speed detecting means, each flow rate determined by the basic flow rate determining means, a relief flow rate determined by the relief flow rate determining means, and the adjustment A swing drive device for a working machine, which calculates an inlet pressure and an outlet pressure of the hydraulic motor assumed based on an adjusted flow rate determined by a flow rate calculation means.

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