Control system for work machine

Abstract

This control system for a work machine comprises: a turning body; a pump that discharges hydraulic oil; a turning motor that is supplied with the hydraulic oil from the pump and turns the turning body; a turning sensor that detects the turning speed of the turning body; and a controller. The controller: calculates a consumption flow rate indicating a flow rate of the hydraulic oil passing through the turning motor on the basis of detection data from the turning sensor; calculates, on the basis of the consumption flow rate, a first turning motor demand flow rate indicating a flow rate of hydraulic oil demanded by the turning motor to maintain an acceleration state when the turning speed of the turning body is in the acceleration state; and controls, on the basis of the first turning motor demand flow rate, a pump flow rate indicating the flow rate of the hydraulic oil discharged from the pump.

Description

Control System of Construction Machine

[0001] The present disclosure relates to a control system of a construction machine.

[0002] In the technical field related to construction machines, a hydraulic drive device as disclosed in Patent Document 1 is known.

[0003] Japanese Patent Application Laid-Open No. 2000-192905

[0004] A construction machine such as an excavator includes a revolving body, a pump that discharges hydraulic oil, and a swing motor that swings the revolving body based on the hydraulic oil supplied from the pump. If the flow rate of the hydraulic oil supplied to the swing motor is inappropriate, the swing of the revolving body may become unstable.

[0005] An object of the present disclosure is to stably swing the revolving body of a construction machine.

[0006] According to the present disclosure, there is provided a control system of a construction machine including a revolving body, a pump that discharges hydraulic oil, a swing motor to which the hydraulic oil from the pump is supplied and that swings the revolving body, a swing sensor that detects the swing speed of the revolving body, and a controller. The controller calculates a consumption flow rate indicating the flow rate of the hydraulic oil passing through the swing motor based on the detection data of the swing sensor, calculates a first swing motor required flow rate indicating the flow rate of the hydraulic oil required by the swing motor based on the consumption flow rate, and controls the pump flow rate indicating the flow rate of the hydraulic oil discharged from the pump based on the first swing motor required flow rate.

[0007] According to the present disclosure, the revolving body of the construction machine swings stably.

[0008] Figure 1 is a side view showing a work machine according to the first embodiment. Figure 2 is a diagram showing the cab of the work machine according to the first embodiment. Figure 3 is a schematic diagram showing the control system of the work machine according to the first embodiment. Figure 4 is a hardware configuration diagram showing the controller according to the first embodiment. Figure 5 is a functional block diagram showing the controller according to the first embodiment. Figure 6 is a diagram for explaining the fourth correlation data stored in the memory unit according to the first embodiment. Figure 7 is a diagram for explaining the relationship between the flow rate consumption of the slewing motor and the requested flow rate of the first slewing motor according to the first embodiment. Figure 8 is a diagram for explaining the relationship between the flow rate consumption of the slewing motor and the rate of change of the pump flow rate according to the first embodiment. Figure 9 is a flowchart showing the control method of the work machine according to the first embodiment. Figure 10 is a diagram for explaining the relationship between the slewing operation amount, flow rate consumption, requested flow rate of the first slewing motor, requested flow rate of the second slewing motor, and pump flow rate according to the first embodiment. Figure 11 is a functional block diagram showing the controller according to the second embodiment. Figure 12 is a diagram showing the relationship between the requested flow rate of the second slewing motor, the requested flow rate of the work machine cylinder, and the target flow rate of the slewing motor according to the second embodiment. Figure 13 is a diagram illustrating the relationship between the upper limit flow rate of the pump according to the second embodiment, the boom cylinder's requested flow rate, the arm cylinder's requested flow rate, the boom cylinder's target flow rate, the arm cylinder's target flow rate, and the second slewing motor's requested flow rate. Figure 14 is a diagram illustrating the relationship between the upper limit flow rate of the pump according to the second embodiment, the work equipment cylinder's requested flow rate, the work equipment cylinder's target flow rate, the first slewing motor's requested flow rate, and the slewing motor's target flow rate. Figure 15 is a functional block diagram showing the controller according to the third embodiment. Figure 16 is a diagram illustrating the 13th and 14th correlation data according to the third embodiment.

[0009] [First Embodiment] The first embodiment will now be described.

[0010] <Work Machinery> Figure 1 is a side view showing work machine 1 according to the first embodiment. Work machine 1 operates at the work site. An example of work machine 1 is a work machine having a slewing body and a work machine attached to the slewing body. In this embodiment, work machine 1 is a hydraulic excavator. Work machine 1 comprises a traveling body 2, a slewing body 3, a work machine 4, a slewing motor 5, a work machine cylinder 6, a controller 7, an operating device 8, and a monitor 9.

[0011] The running body 2 supports the rotating body 3. The running body 2 has a pair of tracks 2A. The working machine 1 moves as the tracks 2A rotate.

[0012] The slewing body 3 is positioned above the traveling body 2. The slewing body 3 is rotatably supported by the traveling body 2. The slewing body 3 has a cab 10. The operator of the work machine 1 is seated in the cab 10. The control device 8 and monitor 9 are located in the cab 10.

[0013] The work implement 4 is rotatably mounted on the slewing body 3. The work implement 4 includes a boom 4A, an arm 4B, and a bucket 4C. The boom 4A is rotatably connected to the front of the slewing body 3. The arm 4B is rotatably connected to the tip of the boom 4A. The bucket 4C is rotatably connected to the tip of the arm 4B.

[0014] The slewing motor 5 rotates the slewing body 3, which is supported by the traveling body 2. The slewing motor 5 is a hydraulic motor driven by hydraulic fluid. The slewing motor 5 is an example of an actuator driven by hydraulic fluid.

[0015] The work implement cylinder 6 operates the work implement 4 attached to the slewing body 3. The work implement cylinder 6 is a hydraulic cylinder driven by hydraulic fluid. The work implement cylinder 6 is an example of an actuator driven by hydraulic fluid. The work implement cylinder 6 includes a boom cylinder 6A, an arm cylinder 6B, and a bucket cylinder 6C.

[0016] The boom cylinder 6A operates the boom 4A. The operation of the boom 4A includes raising and lowering movements. When the boom cylinder 6A extends, the boom 4A moves upward. When the boom cylinder 6A retracts, the boom 4A moves downward.

[0017] The arm cylinder 6B operates the arm 4B. The operation of the arm 4B includes digging and dumping operations. When the arm cylinder 6B extends, the arm 4B performs the digging operation. When the arm cylinder 6B retracts, the arm 4B performs the dumping operation.

[0018] The bucket cylinder 6C operates the bucket 4C. The operation of the bucket 4C includes digging and dumping. When the bucket cylinder 6C extends, the bucket 4C performs the digging operation. When the bucket cylinder 6C retracts, the bucket 4C performs the dumping operation.

[0019] <Cab> Figure 2 shows the cab 10 of the work machine 1 according to the first embodiment. As shown in Figure 2, the operating device 8 and monitor 9 are located in the cab 10. The operating device 8 is operated to operate at least one of the traveling body 2, the rotating body 3, and the work machine 4. The operating device 8 is operated by an operator who is seated in the cab 10. The operator can operate the operating device 8 while seated in the driver's seat 11 located in the cab 10.

[0020] The operating device 8 includes a left work lever 8A and a right work lever 8B, which are operated to operate the slewing body 3 and the work implement 4; a left travel lever 8C and a right travel lever 8D, which are operated to operate the traveling body 2; and a left foot pedal 8E and a right foot pedal 8F.

[0021] When the left work lever 8A is operated in the forward / backward direction, the arm 4B performs a dumping or digging operation. When the left work lever 8A is operated in the left / right direction, the slewing body 3 performs a left or right slewing operation. When the right work lever 8B is operated in the left / right direction, the bucket 4C performs an digging or dumping operation. When the right work lever 8B is operated in the forward / backward direction, the boom 4A performs a lowering or raising operation. Alternatively, when the left work lever 8A is operated in the forward / backward direction, the slewing body 3 may perform a right or left slewing operation. When the left work lever 8A is operated in the left / right direction, the arm 4B may perform a dumping or digging operation.

[0022] When the left travel lever 8C is operated in the forward or backward direction, the left track 2A of the vehicle 2 moves forward or backward. When the right travel lever 8D is operated in the forward or backward direction, the right track 2A of the vehicle 2 moves forward or backward.

[0023] The left foot pedal 8E is linked to the left travel lever 8C. The right foot pedal 8F is linked to the right travel lever 8D. By operating the left foot pedal 8E and the right foot pedal 8F, the vehicle 2 may move forward or backward.

[0024] The monitor 9 is positioned to the right and in front of the driver's seat 11. The monitor 9 includes a display device 9A and an input device 9B. The display device 9A displays display data. The display device 9A provides display data to the operator seated in the cab 10. An example of the display device 9A is a flat panel display such as a liquid crystal display or an organic EL display. The input device 9B is operated by the operator seated in the cab 10. The input device 9B generates input data when operated by the operator. An example of the input device 9B is a touch panel, a button switch, and a computer keyboard.

[0025] <Operation Amount> The operating device 8 is operated to operate the actuators of the work machine 1. The actuators include a slewing motor 5 and a work machine cylinder 6. As described above, the operating device 8 includes a left work lever 8A and a right work lever 8B which are operated to operate the slewing body 3 and the work machine 4. When the operating device 8 is operated, an operation signal (electrical signal) is generated. The operation signal of the operating device 8 is transmitted to the controller 7. The operation signal of the operating device 8 includes the operation amount of the operating device 8. The operation amount may be considered as the signal strength of the operation signal. The operation amount may be considered as the operating angle (tilting angle) of the left work lever 8A and the right work lever 8B. The controller 7 controls the actuators based on the operation amount of the operating device 8.

[0026] In the following description, the amount of manipulation required to operate the slewing motor 5 will be appropriately referred to as the slewing amount, and the amount of manipulation required to operate the work equipment cylinder 6 will be appropriately referred to as the work equipment amount. The work equipment amount includes the boom amount for operating the boom cylinder 6A, the arm amount for operating the arm cylinder 6B, and the bucket amount for operating the bucket cylinder 6C.

[0027] In the following explanation, when the manipulated amount is zero, that is, when the operating device 8 for operating a certain actuator is not being operated, the manipulated amount is considered to be 0%. When the manipulated amount is at its maximum, that is, in the so-called full lever state, the manipulated amount is considered to be 100%.

[0028] In this embodiment, the operation signal (operated quantity) is generated by operating the operating device 8, but the operation signal may be generated by, for example, the controller 7. The controller 7 may automatically generate the operation signal without the operator operating the operating device 8. The operation signal may be generated by a controller other than the controller 7. The other controller may be located outside the work machine 1. The operation signal may be transmitted from the controller located outside the work machine 1 to the controller 7 mounted on the work machine 1. The operating device 8 may be located outside the work machine 1. The work machine 1 may be remotely controlled by a remote control device located outside the work machine 1. When the work machine 1 is remotely controlled by a remote control device, a remote controller connected to the remote control device may generate the operation signal. The operation signal generated by the remote controller may be transmitted to the controller 7 mounted on the work machine 1.

[0029] <Combined Operation> The operating device 8 may be operated so that at least two of the multiple actuators of the work machine 1 operate simultaneously. For example, the operating device 8 may be operated so that the boom cylinder 6A and the arm cylinder 6B operate simultaneously. For example, the operating device 8 may be operated so that the boom cylinder 6A, the arm cylinder 6B and the bucket cylinder 6C operate simultaneously. For example, the operating device 8 may be operated so that the boom cylinder 6A, the arm cylinder 6B and the slewing motor 5 operate simultaneously. In the following description, the operation of the operating device 8 so that at least two actuators operate simultaneously will be appropriately referred to as a combined operation. Also, the operation of at least two actuators simultaneously will be appropriately referred to as a combined operation.

[0030] Furthermore, when the operating device 8 is operated to operate only one of the multiple actuators of the work machine 1, this is appropriately referred to as "single operation." Single operation includes slewing single operation, in which the operating device 8 is operated to operate only the slewing motor 5, and work machine single operation, in which the operating device 8 is operated to operate only the work machine cylinder 6. Work machine single operation includes boom single operation, in which the operating device 8 is operated to operate only the boom cylinder 6A, arm single operation, in which the operating device 8 is operated to operate only the arm cylinder 6B, and bucket single operation, in which the operating device 8 is operated to operate only the bucket cylinder 6C.

[0031] <Control System> Figure 3 is a schematic diagram showing the control system 13 of the work machine 1 according to the first embodiment. The control system 13 includes a hydraulic circuit (hydraulic system) that operates with hydraulic fluid. As shown in Figure 3, the control system 13 includes a controller 7, an operating device 8, a power source 14, a pump 15, a tank 16, a work machine valve 17, a swivel valve 27, a pump passage 19, a suction passage 20, a bottom passage 21, a head passage 22, a first motor passage 23, a second motor passage 24, a work machine cylinder 6, a swivel motor 5, a pump pressure sensor 31, a swivel sensor 32, and a load pressure sensor 33.

[0032] The power source 14 is the power source for the work machine 1. A diesel engine is an example of the power source 14. However, the power source 14 may also be an electric motor. The power source 14 is connected to the pump 15. The power source 14 drives the pump 15.

[0033] Pump 15 is a hydraulic pump that discharges hydraulic fluid. Pump 15 discharges hydraulic fluid supplied to the actuators of the work machine 1. The actuators include a slewing motor 5 and a work machine cylinder 6. In this embodiment, the hydraulic fluid discharged from pump 15 is distributed to each of the multiple actuators. Pump 15 draws in hydraulic fluid contained in tank 16 via suction passage 20. Pump 15 discharges the hydraulic fluid drawn in from tank 16 into pump passage 19. Pump 15 is a swashplate type variable displacement pump. The capacity [cc / rev] of pump 15 is changed by changing the angle of the swashplate of pump 15.

[0034] The work machine cylinder 6 comprises a cylinder tube, a piston movable inside the cylinder tube, and a rod fixed to the piston. The internal space of the cylinder tube is divided by the piston into a bottom chamber 61 and a head chamber 62. At least a portion of the rod is positioned in the head chamber 62.

[0035] The work machine valve 17 includes a directional control valve that controls the flow rate and direction of the hydraulic fluid supplied from the pump 15 to the work machine cylinder 6. The work machine valve 17 is an example of an actuator valve that controls the flow rate and direction of the hydraulic fluid supplied from the pump 15 to the actuator. The work machine valve 17 is located in the bottom passage 21 and the head passage 22. Multiple work machine valves 17 are provided to control the flow rate and direction of the hydraulic fluid supplied from the pump 15 to each of the multiple work machine cylinders 6. In this embodiment, the work machine valve 17 includes a boom valve 17A that controls the flow rate and direction of the hydraulic fluid supplied from the pump 15 to the boom cylinder 6A, an arm valve 17B that controls the flow rate and direction of the hydraulic fluid supplied from the pump 15 to the arm cylinder 6B, and a bucket valve 17C that controls the flow rate and direction of the hydraulic fluid supplied from the pump 15 to the bucket cylinder 6C. The boom valve 17A is located in the boom bottom passage 21A and the boom head passage 22A. The arm valve 17B is located in the arm bottom passage 21B and the arm head passage 22B. The bucket valve 17C is positioned in the bucket bottom passage 21C and the bucket head passage 22C.

[0036] The work implement cylinder 6 extends and retracts to operate the work implement 4 when hydraulic fluid is supplied from the pump 15. When hydraulic fluid from the pump 15 is supplied to the bottom chamber 61 of the work implement cylinder 6 via the work implement valve 17, and the hydraulic fluid from the head chamber 62 of the work implement cylinder 6 is discharged to the tank 16 via the work implement valve 17, the work implement cylinder 6 extends. When hydraulic fluid from the pump 15 is supplied to the head chamber 62 of the work implement cylinder 6 via the work implement valve 17, and the hydraulic fluid from the bottom chamber 61 of the work implement cylinder 6 is discharged to the tank 16 via the work implement valve 17, the work implement cylinder 6 retracts.

[0037] When hydraulic fluid from pump 15 is supplied to the bottom chamber 61 of boom cylinder 6A via boom valve 17A, boom cylinder 6A extends and boom 4A moves upward. When hydraulic fluid from pump 15 is supplied to the head chamber 62 of boom cylinder 6A via boom valve 17A, boom cylinder 6A retracts and boom 4A moves downward.

[0038] When hydraulic fluid from pump 15 is supplied to the bottom chamber 61 of arm cylinder 6B via arm valve 17B, arm cylinder 6B extends and arm 4B performs an excavation operation. When hydraulic fluid from pump 15 is supplied to the head chamber 62 of arm cylinder 6B via arm valve 17B, arm cylinder 6B retracts and arm 4B performs a dumping operation.

[0039] When hydraulic fluid from pump 15 is supplied to the bottom chamber 61 of bucket cylinder 6C via bucket valve 17C, bucket cylinder 6C extends and bucket 4C performs an excavation operation. When hydraulic fluid from pump 15 is supplied to the head chamber 62 of bucket cylinder 6C via bucket valve 17C, bucket cylinder 6C retracts and bucket 4C performs a dumping operation.

[0040] The controller 7 outputs a control command to move the spool of the work machine valve 17 based on the amount of operation of the operating device 8. The spool of the work machine valve 17 moves based on the control command from the controller 7 so that the flow rate and direction of the hydraulic fluid supplied from the pump 15 to the work machine cylinder 6 are controlled.

[0041] The swing valve 27 includes a direction control valve that controls the flow rate and direction of the hydraulic oil supplied from the pump 15 to the swing motor 5. The swing valve 27 is disposed in the first motor flow path 23 and the second motor flow path 24.

[0042] When the swing motor 5 rotates by the supply of the hydraulic oil from the pump 15 to rotate the swing body 3, the hydraulic oil from the pump 15 is supplied to the first port 51 of the swing motor 5 via the swing valve 27, and the hydraulic oil flowing out from the second port 52 of the swing motor 5 is discharged to the tank 16 via the swing valve 27, the swing motor 5 rotates counterclockwise and the swing body 3 swings counterclockwise. When the hydraulic oil from the pump 15 is supplied to the second port 52 of the swing motor 5 via the swing valve 27, and the hydraulic oil flowing out from the first port 51 of the swing motor 5 is discharged to the tank 16 via the swing valve 27, the swing motor 5 rotates clockwise and the swing body 3 swings clockwise.

[0043] The controller 7 outputs a control command for moving the spool of the swing valve 27 based on the operation amount of the operation device 8. The spool of the swing valve 27 moves so that the flow rate and direction of the hydraulic oil supplied from the pump 15 to the swing motor 5 are controlled based on the control command from the controller 7.

[0044] The pump pressure sensor 31 detects the pressure of the hydraulic oil discharged by the pump 15. In the embodiment, the pump pressure sensor 31 detects the pressure of the hydraulic oil in the pump flow path 19. The detection data of the pump pressure sensor 31 is transmitted to the controller 7.

[0045] The swing sensor 32 detects the swing speed of the swing body 3. As the swing sensor 32, a potentiometer is exemplified. Note that the swing sensor 32 may detect the rotation speed of the swing motor 5. The detection data of the swing sensor 32 is transmitted to the controller 7.

[0046] The load pressure sensor 33 detects the meter-in pressure indicating the pressure of the hydraulic oil supplied from the pump 15 to the swing motor 5. The detection data of the load pressure sensor 33 is transmitted to the controller 7. In the embodiment, the load pressure sensor 33 includes a first load pressure sensor 33A that detects the pressure of the hydraulic oil in the first motor passage 23 between the swing valve 27 and the first port 51 of the swing motor 5, and a second load pressure sensor 33B that detects the pressure of the hydraulic oil in the second motor passage 24 between the swing valve 27 and the second port 52 of the swing motor 5.

[0047] When the hydraulic oil from the pump 15 is supplied to the first port 51 of the swing motor 5 via the swing valve 27, the first load pressure sensor 33A detects the meter-in pressure of the hydraulic oil supplied to the first port 51 of the swing motor 5. When the hydraulic oil from the pump 15 is supplied to the first port 51 of the swing motor 5 via the swing valve 27, the second load pressure sensor 33B detects the meter-out pressure indicating the pressure of the hydraulic oil flowing out from the second port 52 of the swing motor 5.

[0048] When the hydraulic oil from the pump 15 is supplied to the second port 52 of the swing motor 5 via the swing valve 27, the second load pressure sensor 33B detects the meter-in pressure of the hydraulic oil supplied to the second port 52 of the swing motor 5. When the hydraulic oil from the pump 15 is supplied to the second port 52 of the swing motor 5 via the swing valve 27, the first load pressure sensor 33A detects the meter-out pressure indicating the pressure of the hydraulic oil flowing out from the first port 51 of the swing motor 5.

[0049] The meter-in pressure is equal to the load pressure acting on the swing motor 5. The first load pressure sensor 33A detects the load pressure acting on the swing motor 5 when the hydraulic oil is supplied from the first motor passage 23 to the first port 51 and the swing motor 5 rotates counterclockwise. The second load pressure sensor 33B detects the load pressure acting on the swing motor 5 when the hydraulic oil is supplied from the second motor passage 24 to the second port 52 and the swing motor 5 rotates clockwise.

[0050] <Controller> Figure 4 is a hardware configuration diagram showing a controller 7 according to the first embodiment. The controller 7 includes a computer 12. The computer 12 has a processor 12A such as a CPU (Central Processing Unit), a main memory 12B including non-volatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory), a storage 12C, an input / output interface 12D including input / output circuits, and a communication interface 12E including communication circuits. The functions of the controller 7 are stored in the storage 12C as a computer program 12F. The processor 12A reads the computer program 12F from the storage 12C, loads it into the main memory 12B, and executes processing according to the computer program 12F. The computer program 12F may be distributed to the computer 12 via a network.

[0051] <Control in standalone swivel operation> Figure 5 is a functional block diagram showing the controller 7 according to the first embodiment. In the first embodiment, the control system 13 for standalone swivel operation will be described. In the first embodiment, the controller 7 outputs control commands to control the swivel valve 27 and the pump 15. The operating device 8 and the swivel sensor 32 are connected to the controller 7. The controller 7 controls the swivel valve 27 and the pump 15 based on the swivel operation amount Es of the operating device 8 and the detection data of the swivel sensor 32.

[0052] The controller 7 has a memory unit 78 and a plurality of functional units. The functions of the memory unit 78 of the controller 7 are performed by the storage 12C. The functions of the functional units of the controller 7 are performed by the processor 12A. The functional units of the controller 7 include a target swivel speed calculation unit 71, a second swivel motor required flow rate calculation unit 72, a swivel motor consumption flow rate calculation unit 73, a first swivel motor required flow rate calculation unit 74, a selection unit 75, a swivel valve control unit 76, and a pump control unit 77.

[0053] The target turning speed calculation unit 71 obtains the turning operation amount Es for operating the turning motor 5 from the operating device 8. Based on the turning operation amount Es from the operating device 8, the target turning speed calculation unit 71 calculates the target turning speed Vrs, which indicates the target value of the turning speed of the turning body 3. In this embodiment, the target turning speed Vrs is a value proportional to the turning operation amount Es. The larger the turning operation amount Es, the higher the target turning speed Vrs. If a first correlation data showing the relationship between the turning operation amount Es and the target turning speed Vrs is predetermined, the target turning speed calculation unit 71 may calculate the target turning speed Vrs by inputting the turning operation amount Es into the first correlation data.

[0054] The rotational speed of the rotating body 3 (target rotational speed Vrs) and the rotational speed of the rotating motor 5 (target rotational speed) correspond one-to-one. Calculating the target rotational speed Vrs of the rotating body 3 may also be considered a concept that includes calculating the target rotational speed of the rotating motor 5.

[0055] The second slewing motor flow rate calculation unit 72 calculates the second slewing motor flow rate Qrs, which indicates the flow rate of hydraulic fluid required by the slewing motor 5, based on the slewing operation amount Es of the operating device 8. In this embodiment, the second slewing motor flow rate calculation unit 72 calculates the second slewing motor flow rate Qrs based on the target slewing speed Vrs calculated from the slewing operation amount Es.

[0056] In this embodiment, the required flow rate of the hydraulic fluid refers to the target value of the flow rate of the hydraulic fluid to be supplied to the actuator.

[0057] The second slewing motor required flow rate Qrs refers to the required flow rate of hydraulic fluid required by the slewing motor 5 when the slewing speed of the slewing body 3 is in a steady state. A steady state of rotation of the slewing body 3 means that the slewing speed of the slewing body 3 is constant (non-accelerating state). In other words, the second slewing motor required flow rate Qrs refers to the required flow rate of the slewing motor 5 when the rotation operation amount Es is constant. In this embodiment, the second slewing motor required flow rate Qrs is a value proportional to the rotation operation amount Es (or target rotation speed Vrs). The larger the rotation operation amount Es, the greater the second slewing motor required flow rate Qrs. If a second correlation data showing the relationship between the rotation operation amount Es and the second slewing motor required flow rate Qrs is predetermined, the second slewing motor required flow rate calculation unit 72 may calculate the second slewing motor required flow rate Qrs by inputting the rotation operation amount Es into the second correlation data.

[0058] As described above, there is a one-to-one correspondence between the rotational speed of the slewing body 3 and the rotational speed of the slewing motor 5. The second slewing motor required flow rate Qrs may also be a concept that includes the required flow rate of hydraulic fluid required by the slewing motor 5 in a steady state where the rotational speed of the slewing motor 5 is constant.

[0059] The slewing motor flow rate calculation unit 73 acquires detection data from the slewing sensor 32. The detection data from the slewing sensor 32 indicates the slewing speed of the slewing body 3. Based on the detection data from the slewing sensor 32, the slewing motor flow rate calculation unit 73 calculates the flow rate Qc, which indicates the flow rate of the hydraulic fluid passing through the slewing motor 5. The flow rate Qc is an estimated value of the flow rate of the hydraulic fluid passing through the slewing motor 5. When the hydraulic fluid flows into the first port 51 of the slewing motor 5, the flow rate of the hydraulic fluid passing through the slewing motor 5 is equal to the flow rate of the hydraulic fluid flowing into the first port 51 and the flow rate of the hydraulic fluid flowing out from the second port 52. When the hydraulic fluid flows into the second port 52 of the slewing motor 5, the flow rate of the hydraulic fluid passing through the slewing motor 5 is equal to the flow rate of the hydraulic fluid flowing into the second port 52 and the flow rate of the hydraulic fluid flowing out from the first port 51. In this embodiment, the flow rate Qc is a value proportional to the detection data from the slewing sensor 32 (the slewing speed of the slewing body 3). If a third correlation data showing the relationship between the rotation speed of the rotating body 3 and the consumption flow rate Qc is predetermined, the rotation motor consumption flow rate calculation unit 73 may calculate the consumption flow rate Qc by inputting the detection data of the rotation sensor 32 into the third correlation data.

[0060] The first swing motor required flow rate calculation unit 74 calculates the first swing motor required flow rate Qra, which indicates the flow rate of hydraulic fluid required by the swing motor 5, based on the consumption flow rate Qc of the swing motor 5.

[0061] The first swing motor required flow rate Qra refers to the required flow rate of hydraulic fluid required by the swing motor 5 to maintain the accelerated state of the swing body 3 when the swing speed of the swing body 3 is in an accelerating state. The swing speed of the swing body 3 being in an accelerating state means that the swing speed of the swing body 3 is increasing. In other words, the first swing motor required flow rate Qra refers to the required flow rate of the swing motor 5 before the swing speed of the swing body 3 reaches the target swing speed Vrs.

[0062] In the following description, the steady state in which the rotation speed of the rotating body 3 is constant will be appropriately referred to as the "steady rotation state." The accelerated state in which the rotation speed of the rotating body 3 is accelerating will be appropriately referred to as the "accelerated rotation state."

[0063] As described above, there is a one-to-one correspondence between the rotational speed of the slewing body 3 and the rotational speed of the slewing motor 5. The first slewing motor required flow rate Qra may also be a concept that includes the required flow rate of hydraulic fluid required by the slewing motor 5 in an acceleration state where the rotational speed of the slewing motor 5 increases.

[0064] The first swing motor request flow rate calculation unit 74 calculates an assist flow rate Qa, which indicates the flow rate of hydraulic fluid to pressurize the hydraulic fluid in the swing motor 5, based on the consumption flow rate Qc. In this embodiment, a fourth correlation data showing the relationship between the consumption flow rate Qc and the assist flow rate Qa is predetermined. The fourth correlation data is stored in the storage unit 78 in advance. The first swing motor request flow rate calculation unit 74 calculates the assist flow rate Qa by inputting the consumption flow rate Qc into the fourth correlation data. After calculating the assist flow rate Qa, the first swing motor request flow rate calculation unit 74 adds the assist flow rate Qa to the consumption flow rate Qc to calculate the first swing motor request flow rate Qra.

[0065] Figure 6 is a diagram illustrating the fourth correlation data stored in the storage unit 78 according to the first embodiment. In the lower graph of Figure 6, the horizontal axis represents the flow rate Qc consumed by the swing motor 5, and the vertical axis represents the assist flow rate Qa. In the upper graph of Figure 6, the horizontal axis represents the flow rate Qc consumed by the swing motor 5, and the vertical axis represents the first swing motor requested flow rate Qra and the consumed flow rate Qc.

[0066] In the lower graph of Figure 6, line La represents the fourth correlation data. The fourth correlation data shows the relationship between the consumption flow rate Qc and the assist flow rate Qa. In this embodiment, the assist flow rate Qa decreases as the consumption flow rate Qc increases. When the consumption flow rate Qc is in the range from zero to a value greater than zero, Qc1, the assist flow rate Qa is set to value Qa0. When the consumption flow rate Qc is in the range from value Qc1 to a value greater than Qc1, Qc2, the assist flow rate Qa decreases from value Qa0 to a value less than Qa0, Qa2. When the consumption flow rate Qc is in the range from value Qc2 to a value greater than Qc2, Qc3, the assist flow rate Qa decreases from value Qa2 to zero.

[0067] The first swing motor required flow rate calculation unit 74 can calculate the assist flow rate Qa by inputting the consumption flow rate Qc calculated by the swing motor consumption flow rate calculation unit 73 into the fourth correlation data indicated by line La. For example, if the consumption flow rate Qc is value Qc1, inputting value Qc1 into the fourth correlation data will calculate the assist flow rate Qa as value Qa0. If the consumption flow rate Qc is value Qc2, inputting value Qc2 into the fourth correlation data will calculate the assist flow rate Qa as value Qa2.

[0068] Note that the fourth correlation data shown in Figure 6 is just an example. The assist flow rate Qa should decrease as the consumption flow rate Qc increases, and should eventually become zero. In other words, line La can be a broken line as shown in the lower graph of Figure 6, a straight line, or a curve.

[0069] In the upper graph of Figure 6, line Lc represents the flow rate Qc consumed by the swing motor 5. In the upper graph of Figure 6, line Lra represents the first swing motor's requested flow rate Qra. When the swing acceleration state is reached, the first swing motor's requested flow rate calculation unit 74 calculates the first swing motor's requested flow rate Qra by adding the assist flow rate Qa to the flow rate Qc consumed by the swing motor 5.

[0070] For example, when the rotation speed of the rotating body 3 is accelerating and the consumption flow rate Qc is zero, the first rotation motor required flow rate calculation unit 74 adds the value Qa0 to the value Qrs0 to calculate the value Qra0 as the first rotation motor required flow rate Qra.

[0071] When the rotation speed of the rotating body 3 is accelerating, and the consumption flow rate Qc is value Qc1, the first rotation motor required flow rate calculation unit 74 adds the value Qa0 to the value Qrs1 to calculate the value Qra1 as the first rotation motor required flow rate Qra.

[0072] When the rotational speed of the rotating body 3 is accelerating, and the consumption flow rate Qc is value Qc2, the first rotational motor required flow rate calculation unit 74 adds value Qa2 to value Qrs2 to calculate value Qra2 as the first rotational motor required flow rate Qra.

[0073] When the rotation speed of the rotating body 3 is accelerating, and the consumption flow rate Qc is value Qc3, the first rotation motor required flow rate calculation unit 74 adds the value Qc3 to the value Qrs3 to calculate the value Qra3 as the first rotation motor required flow rate Qra. In the example shown in Figure 6, the value Qra3 is equal to the value Qrs3 (= Qc3).

[0074] The selection unit 75 selects the smaller of the two requested flow rates for the first and second swivel motors, Qr.

[0075] The swivel valve control unit 76 calculates the target opening area Ars of the swivel valve 27 based on the second swivel motor's requested flow rate Qrs and a calculation formula (for example, Bernoulli's theorem). The larger the second swivel motor's requested flow rate Qrs, the larger the target opening area Ars. The swivel valve control unit 76 controls the swivel valve 27 so that its opening area becomes the target opening area Ars. The swivel valve control unit 76 may also calculate the target opening area Ars of the swivel valve 27 by multiplying the second swivel motor's requested flow rate Qrs by a predetermined positive proportionality constant. If a fifth correlation data showing the relationship between the second swivel motor's requested flow rate Qrs and the target opening area Ars is predetermined, the swivel valve control unit 76 may calculate the target opening area Ars of the swivel valve 27 by inputting the second swivel motor's requested flow rate Qrs into the fifth correlation data.

[0076] When the selection unit 75 selects the first swing motor request flow rate Qra, that is, when the first swing motor request flow rate Qra is less than the second swing motor request flow rate Qrs, it means that the swing acceleration state is entered. When the swing acceleration state is entered, the pump control unit 77 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15, based on the first swing motor request flow rate Qra. The pump control unit 77 controls the pump 15 so that the first swing motor request flow rate Qra and the pump flow rate Qp match.

[0077] When the selection unit 75 selects the second swivel motor request flow rate Qrs, that is, when the second swivel motor request flow rate Qrs is less than the first swivel motor request flow rate Qra, it means that a steady-state swivel state is reached. When a steady-state swivel state is reached, the pump control unit 77 controls the pump flow rate Qp based on the second swivel motor request flow rate Qrs. The pump control unit 77 controls the pump 15 so that the second swivel motor request flow rate Qrs and the pump flow rate Qp match.

[0078] <Changing the Assist Flow Rate> Figure 7 is a diagram illustrating the relationship between the flow rate Qc consumed by the swing motor 5 and the flow rate Qra requested by the first swing motor according to the first embodiment. In the graph of Figure 7, the horizontal axis represents the flow rate Qc consumed by the swing motor 5, and the vertical axis represents the flow rate Qra requested by the first swing motor.

[0079] In the graph of Figure 7, line Lra represents the first swing motor required flow rate Qra when the swing speed of the swinging body 3 is accelerating. Line Lra1 represents the first swing motor required flow rate Qra1 when the target swing speed Vrs of the swinging body 3 is the first target swing speed Vrs1 when the swing speed of the swinging body 3 is accelerating. Line Lra2 represents the first swing motor required flow rate Qra2 when the target swing speed Vrs of the swinging body 3 is the second target swing speed Vrs2 when the swing speed of the swinging body 3 is accelerating. The second target swing speed Vrs2 is a higher value than the first target swing speed Vrs1. For the same consumption flow rate Qc, the first swing motor requested flow rate Qra2 when the target swing speed Vrs of the swinging body 3 is the second target swing speed Vrs2 is greater than the first swing motor requested flow rate Qra1 when the target swing speed Vrs of the swinging body 3 is the first target swing speed Vrs1. As described above, when the swing speed of the swinging body 3 is in an accelerating state, the first swing motor requested flow rate calculation unit 74 adds the assist flow rate Qa to the consumption flow rate Qc to calculate the first swing motor requested flow rate Qra. The assist flow rate Qa when the target swing speed Vrs of the swinging body 3 is the second target swing speed Vrs2 is greater than the assist flow rate Qa when the target swing speed Vrs of the swinging body 3 is the first target swing speed Vrs1. The fourth correlation data may be set so that the assist flow rate Qa increases as the target swing speed Vrs increases.

[0080] In other words, multiple fourth correlation data showing the relationship between the consumption flow rate Qc and the assist flow rate Qa may be predetermined. Multiple fourth correlation data showing the relationship between the consumption flow rate Qc and the assist flow rate Qa may be stored in the memory unit 78 in advance. The assist flow rate Qa may be changed based on the target turning speed Vrs. The higher the target turning speed Vrs, the greater the assist flow rate Qa may be.

[0081] The target turning speed Vrs and the turning maneuver Es correspond one-to-one. The target turning speed Vrs and the turning maneuver Es are proportional. The assist flow rate Qa may be changed based on the turning maneuver Es. The assist flow rate Qa may be higher as the turning maneuver Es increases.

[0082] Line Lra1 shown in Figure 7 is the same as line Lra shown in Figure 6. In the example shown in Figure 7, if the consumption flow rate Qc is zero and the target rotation speed Vrs of the slewing body 3 is the first target rotation speed Vrs1, the value Qra0 is calculated as the first rotation motor required flow rate Qra. If the consumption flow rate Qc is zero and the target rotation speed Vrs of the slewing body 3 is the second target rotation speed Vrs2, the value Qra02, which is greater than the value Qra0, is calculated as the first rotation motor required flow rate Qra. If the consumption flow rate Qc is a value Qc32, which is greater than the value Qc3, and the target rotation speed Vrs of the slewing body 3 is the second target rotation speed Vrs2, the value Qra32, which is greater than the value Qra3, is calculated as the first rotation motor required flow rate Qra.

[0083] Based on the target turning speed Vrs (turning operation amount Es), the assist flow rate Qa is changed, and the first turning motor's required flow rate Qra is changed, thereby supplying the turning motor 5 with the appropriate amount of hydraulic fluid. The higher the target turning speed Vrs (the larger the turning operation amount Es), the greater the assist flow rate Qa and the greater the first turning motor's required flow rate Qra, so that the turning motor 5 is supplied with a sufficient amount of hydraulic fluid. Since the first turning motor's required flow rate Qra is increased and the turning motor 5 is supplied with a sufficient amount of hydraulic fluid, the turning body 3 can accelerate appropriately when it is in an accelerating state.

[0084] <Time-dependent change rate of pump flow rate> Figure 8 is a diagram illustrating the relationship between the time-dependent change rate R of the slewing motor 5's consumption flow rate Qc and the pump flow rate Qp according to the first embodiment. In the graph of Figure 8, the horizontal axis represents the consumption flow rate Qc of the slewing motor 5, and the vertical axis represents the time-dependent change rate R of the pump flow rate Qp. The storage unit 78 has in advance stored sixth correlation data, which shows the relationship between the consumption flow rate Qc and the time-dependent change rate R of the pump flow rate Qp, as shown by the line LR in Figure 8. The pump control unit 77 may change the time-dependent change rate R of the pump flow rate Qp based on the consumption flow rate Qc and the sixth correlation data. When the slewing speed of the slewing body 3 is in a steady state and slewing is operated alone, changing the time-dependent change rate R of the pump flow rate Qp includes changing the time-dependent change rate Qrs of the second slewing motor's requested flow rate.

[0085] As shown in Figure 8, the rate of change R of the pump flow rate Qp may increase as the consumption flow rate Qc increases. In the example shown in Figure 8, in the range where the consumption flow rate Qc is from zero to a value greater than zero, Qc4, the rate of change R of the pump flow rate Qp is calculated as R1. In the range where the consumption flow rate Qc is from value Qc4 to a value greater than Qc4, Qc5, the rate of change R of the pump flow rate Qp increases from value R1 to a value greater than R1, R2.

[0086] When the flow rate Qc consumed by the slewing motor 5 is low, that is, when the slewing speed of the slewing body 3 is low, the rate of change of the pump flow rate Qp over time is low. Therefore, if the operating device 8 is operated to start slewing from a stationary state where the slewing body 3 is not slewing relative to the traveling body 2, for example, the slewing body 3 can start slewing with a low slewing acceleration. In other words, the slewing body 3 can accelerate gradually from a stationary state. As a result, in the low-speed range of slewing speed, the deterioration of the stability of the slewing body 3 is suppressed.

[0087] When the flow rate Qc consumed by the slewing motor 5 is high, that is, when the slewing speed of the slewing body 3 is high, the rate of change of the pump flow rate Qp over time is high. For example, if the operating device 8 is operated to move the slewing body 3 from a state where it is slewing at a first slewing speed to a second slewing speed which is higher than the first slewing speed, the slewing body 3 can transition from the state where it is slewing at the first slewing speed to the state where it is slewing at the second slewing speed with high slewing acceleration. In other words, the slewing body 3 can transition from the state where it is slewing at the first slewing speed to the state where it is slewing at the second slewing speed in a short amount of time. As a result, in the high-speed range, the slewing body 3 rotates quickly, thus suppressing a decrease in work efficiency.

[0088] <Control Method> Figure 9 is a flowchart showing the control method for the work machine 1 according to the first embodiment. Figure 9 is a flowchart showing the control method for the work machine 1 during rotation-only operation.

[0089] The target rotation speed calculation unit 71 acquires the rotation operation amount Es to operate the rotation motor 5. Based on the rotation operation amount Es, the target rotation speed calculation unit 71 calculates the target rotation speed Vrs, which indicates the target value of the rotation speed of the rotation body 3 (step SA1).

[0090] The second slewing motor flow rate calculation unit 72 calculates the second slewing motor flow rate Qrs, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 when the slewing speed of the slewing body 3 is in a steady state, based on the target slewing speed Vrs. Alternatively, the second slewing motor flow rate calculation unit 72 may calculate the second slewing motor flow rate Qrs based on the slewing operation amount Es of the operating device 8 (step SA2).

[0091] The swivel valve control unit 76 controls the opening area of ​​the swivel valve 27 based on the second swivel motor's requested flow rate Qrs. The swivel valve control unit 76 controls the opening area of ​​the swivel valve 27 so that it becomes the target opening area calculated based on the second swivel motor's requested flow rate Qrs (step SA3).

[0092] The swing motor flow rate calculation unit 73 acquires detection data from the swing sensor 32. Based on the detection data from the swing sensor 32, the swing motor flow rate calculation unit 73 calculates the flow rate Qc, which indicates the flow rate of the hydraulic fluid passing through the swing motor 5 (step SA4).

[0093] The first slewing motor flow rate calculation unit 74 calculates the first slewing motor flow rate Qra, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 to maintain the accelerated state when the slewing speed of the slewing body 3 is in an accelerated state, based on the flow rate Qc consumed by the slewing motor 5. The first slewing motor flow rate calculation unit 74 calculates the assist flow rate Qa based on the flow rate Qc consumed by the slewing motor 5 and the fourth correlation data explained with reference to Figure 6. The first slewing motor flow rate calculation unit 74 calculates the assist flow rate Qa corresponding to the flow rate Qc by inputting the flow rate Qc calculated by the slewing motor flow rate calculation unit 73 into the fourth correlation data. The first slewing motor flow rate calculation unit 74 adds the assist flow rate Qa to the flow rate Qc to calculate the first slewing motor flow rate Qra corresponding to the flow rate Qc (step SA5).

[0094] The selection unit 75 selects the smaller of the two requested flow rates for the first and second swing motors, Qr (step SA6).

[0095] The pump control unit 77 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15, based on the swivel motor request flow rate Qr selected by the selection unit 75. For example, the pump control unit 77 inputs the predetermined target rotational speed of the pump 15 and the swivel motor request flow rate Qr selected by the selection unit 75 into the relationship formula between pump capacity, pump rotational speed, and pump flow rate to calculate the target capacity of the pump 15. Based on the target capacity of the pump 15, it calculates a control command for the pump 15, and controls the capacity of the pump 15 by controlling the swash plate of the pump 15 based on the control command for the pump 15. By controlling the capacity of the pump 15, the pump control unit 77 can control the pump flow rate Qp, which indicates the flow rate of hydraulic fluid (step SA7).

[0096] Figure 10 is a diagram illustrating the relationship between the swing operation amount Es, the consumption flow rate Qc, the first swing motor's requested flow rate Qra, the second swing motor's requested flow rate Qrs, and the pump flow rate Qp according to the first embodiment. In the graph of Figure 10, the horizontal axis represents time, and the vertical axis represents the flow rate of the hydraulic fluid. Line Ls represents the swing operation amount Es. Line Lc represents the consumption flow rate Qc of the swing motor 5. Line Lra represents the first swing motor's requested flow rate Qra. Line Lrs represents the second swing motor's requested flow rate Qrs. Line Lp represents the pump flow rate Qp of the pump 15.

[0097] Figure 10 shows the relationship between time and hydraulic fluid flow rate in the case of a single-unit rotation operation. As shown in Figure 10, when the operation of the control device 8 is started at time 0, the rotation operation amount Es starts to increase and eventually reaches 100%. When the rotation operation amount Es is input to the controller 7, the controller 7 controls the pump flow rate Qp and the opening area of ​​the rotation valve 27, and the rotation speed of the rotation body 3 transitions from an accelerating state to a steady state and then to a deceleration state.

[0098] During acceleration, the flow rate Qrs required by the second swing motor increases proportionally with time. During acceleration, the flow rate Qc consumed gradually increases. During acceleration, the flow rate Qra required by the first swing motor is calculated by adding the assist flow rate Qa to the flow rate Qc consumed.

[0099] During the period from time 0, immediately after the operation of the control device 8 is started, to time t1, which is after time 0, the requested flow rate Qra for the first swing motor is greater than the requested flow rate Qrs for the second swing motor. Time t1 is an intermediate point in the acceleration state. During the period from time 0 to time t1, the selection unit 75 selects the requested flow rate Qrs for the second swing motor, and the pump flow rate Qp is controlled based on the requested flow rate Qrs for the second swing motor. As shown by lines Lrs and Lp, during the period from time 0 to time t1, the pump flow rate Qp is substantially the same as the requested flow rate Qrs for the second swing motor. Since the requested flow rate Qrs for the second swing motor is calculated based on the swing operation amount Es, during the period from time 0 to time t1, the hydraulic fluid at a pump flow rate Qp calculated based on the time change rate of the swing operation amount Es and the pump flow rate Qp is discharged from the pump 15. In other words, during the period from time 0 to time t1, the rotation speed of the slewing body 3 is in line with the time rate of change of the rotation operation amount Es and the pump flow rate Qp. To put it another way, during the period from time 0 to time t1, that is, in the low-speed range of rotation speed, the slewing body 3 can accelerate gradually from a stationary state, suppressing a decrease in the stability of the slewing body 3, and the slewing body 3 rotates stably even without the operator making fine adjustments to the control device 8.

[0100] During the period from time t1 to time t2, which is later than time t1, the first swing motor requested flow rate Qra is less than the second swing motor requested flow rate Qrs. Time t2 is the end of the acceleration state. During the period from time t1 to time t2, the first swing motor requested flow rate Qra is selected in the selection unit 75, and the pump flow rate Qp is controlled based on the first swing motor requested flow rate Qra. As shown by lines Lra and Lp, during the period from time t1 to time t2, the pump flow rate Qp is substantially the same as the first swing motor requested flow rate Qra. The first swing motor requested flow rate Qra is calculated by adding the assist flow rate Qa, which is determined based on the detection data (consumption flow rate Qc) of the swing sensor 32, to the consumption flow rate Qc. During the period from time t1 to time t2, the hydraulic fluid at the pump flow rate Qp calculated based on the detection data (consumption flow rate Qc) of the swing sensor 32 is discharged from the pump 15. In other words, during the period from time t1 to time t2, the rotation speed of the rotating body 3 will be a value in line with the fourth correlation data, which shows the relationship between the detection data (consumption flow rate Qc) of the rotation sensor 32 and the assist flow rate Qa, which is predetermined. In other words, during the period from time t1 to time t2, the rotating body 3 will rotate at an appropriate rotation speed even without the operator making any fine adjustments to the control device 8.

[0101] During the period from time t2 to time t3 (which is later than time t2), the first swing motor's requested flow rate Qra is greater than the second swing motor's requested flow rate Qrs. Time t3 is the end of the steady state. During the period from time t2 to time t3, the selection unit 75 selects the second swing motor's requested flow rate Qrs, and the pump flow rate Qp is controlled based on the second swing motor's requested flow rate Qrs. As shown by lines Lrs and Lp, during the period from time t2 to time t3, the pump flow rate Qp is substantially the same as the second swing motor's requested flow rate Qrs. Since the second swing motor's requested flow rate Qrs is calculated based on the swing operation amount Es, during the period from time t2 to time t3, the hydraulic fluid at the pump flow rate Qp calculated based on the swing operation amount Es is discharged from the pump 15. That is, during the period from time t2 to time t3, the swing speed of the swing body 3 is in line with the swing operation amount Es. During the period from time t2 to time t3, the rotation speed of the rotating body 3 is not based on the data detected by the rotation sensor 32, but rather on the rotation operation amount Es. For example, even if an error occurs in the data detected by the rotation sensor 32, the data detected by the rotation sensor 32 is not reflected in the rotation speed of the rotating body 3, so in a steady state, the rotating body 3 can rotate at a constant rotation speed.

[0102] During the deceleration period from time t3 onward, the first swing motor's requested flow rate Qra is greater than the second swing motor's requested flow rate Qrs. During the period from time t3 onward, the second swing motor's requested flow rate Qrs is selected by the selection unit 75, and the pump flow rate Qp is controlled based on the second swing motor's requested flow rate Qrs. As shown by lines Lrs and Lp, during the period from time t3 onward, the pump flow rate Qp is substantially the same as the second swing motor's requested flow rate Qrs. Since the second swing motor's requested flow rate Qrs is calculated based on the swing operation amount Es, during the period from time t3 onward, the hydraulic fluid at the pump flow rate Qp calculated based on the swing operation amount Es is discharged from the pump 15. In other words, during the period from time t3 onward, the swing speed of the swing body 3 is a value in line with the swing operation amount Es.

[0103] <When the swivel sensor is abnormal> As described above, the assist flow rate Qa and the first swivel motor requested flow rate Qra are determined based on the detection data of the swivel sensor 32. If the swivel sensor 32 is abnormal, the first swivel motor requested flow rate calculation unit 74 cannot calculate the first swivel motor requested flow rate Qra. An abnormality in the swivel sensor 32 includes, for example, the controller 7 being unable to acquire detection data from the swivel sensor 32 due to a malfunction of the swivel sensor 32. If the swivel sensor 32 is abnormal, the pump control unit 77 may control the pump flow rate Qp based on the second swivel motor requested flow rate Qrs.

[0104] <Effects> As described above, in a single-rotation operation, the controller 7 calculates a consumption flow rate Qc, which indicates the flow rate of hydraulic fluid passing through the rotation motor 5, based on the detection data of the rotation sensor 32. Based on the consumption flow rate Qc, the controller 7 calculates a first rotation motor request flow rate Qra, which indicates the flow rate of hydraulic fluid required by the rotation motor 5 to maintain the accelerated rotation state when the rotation speed of the rotation body 3 is in an accelerated state. Based on the first rotation motor request flow rate Qra, the controller 7 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15.

[0105] According to the embodiment, in a single-rotation operation, when the rotation speed of the rotating body 3 is accelerating, a first rotation motor request flow rate Qra of the rotation motor 5 is calculated to maintain the acceleration state of the rotating body 3. Based on the first rotation motor request flow rate Qra, the pump flow rate Qp of the pump 15 is controlled so that the appropriate flow rate of hydraulic fluid is supplied from the pump 15 to the rotation motor 5. Since the appropriate flow rate of hydraulic fluid is supplied from the pump 15 to the rotation motor 5 when the rotating body 3 is accelerating, the rotating body 3 can rotate stably. The rotating body 3 can rotate with sufficient rotational acceleration.

[0106] The controller 7 acquires the rotation operation amount Es for operating the rotation motor 5, calculates the second rotation motor required flow rate Qrs based on the rotation operation amount Es, which indicates the flow rate of hydraulic fluid required by the rotation motor 5 when the rotation speed of the rotation body 3 is in a steady state, calculates the assist flow rate Qa based on the consumption flow rate Qc, which indicates the flow rate of hydraulic fluid required to pressurize the hydraulic fluid in the rotation motor 5, and calculates the first rotation motor required flow rate Qra by adding the assist flow rate Qa to the second rotation motor required flow rate Qrs. The assist flow rate Qa is calculated by inputting the consumption flow rate Qc into the fourth correlation data as explained with reference to Figure 6. The first rotation motor required flow rate Qra is calculated by adding the assist flow rate Qa to the consumption flow rate Qc.

[0107] As explained with reference to Figure 6, in the fourth correlation data, the assist flow rate Qa decreases as the consumption flow rate Qc increases. When the consumption flow rate Qc is low, that is, when the rotation speed of the slewing body 3 is low, a large amount of assist flow rate Qa is added to the consumption flow rate Qc. In the low-speed range of the slewing body 3's rotation speed, a large amount of assist flow rate Qa is added to the consumption flow rate Qc, so the slewing body 3 can rotate with sufficient rotational acceleration. When the consumption flow rate Qc is high, that is, when the rotation speed of the slewing body 3 is high, a small amount of assist flow rate Qa is added to the consumption flow rate Qc. In the high-speed range of the slewing body 3's rotation speed, a small amount of assist flow rate Qa is added to the consumption flow rate Qc, so the slewing body 3 can rotate with rotational acceleration in line with the rotational operation amount Es.

[0108] As explained with reference to Figure 7, the assist flow rate Qa is changed based on the target turning speed Vrs (turning operation amount Es). Based on the target turning speed Vrs, the assist flow rate Qa is changed, and the first turning motor's required flow rate Qra is changed, so that hydraulic fluid is supplied appropriately to the turning motor 5. The higher the target turning speed Vrs, the greater the assist flow rate Qa and the greater the first turning motor's required flow rate Qra, so that a sufficient flow rate of hydraulic fluid is supplied to the turning motor 5. Since the first turning motor's required flow rate Qra is increased and a sufficient flow rate of hydraulic fluid is supplied to the turning motor 5, the turning body 3 can be sufficiently accelerated when it is in the acceleration state.

[0109] The selection unit 75 selects the smaller of the first requested flow rate Qra and the second requested flow rate Qrs, whichever is smaller, the requested flow rate Qr for the slewing motor. The pump control unit 77 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15, based on the requested flow rate Qr for the slewing motor selected by the selection unit 75. As explained with reference to Figure 10, in the period from time 0, immediately after the operation of the operating device 8 is started, to time t1, the requested flow rate Qra for the first slewing motor is greater than the requested flow rate Qrs for the second slewing motor, and hydraulic fluid at a pump flow rate Qp calculated based on the time rate of change of the slewing operation amount Es and the pump flow rate Qp is discharged from the pump 15. That is, in the period from time 0 to time t1, the slewing speed of the slewing body 3 is in line with the time rate of change of the slewing operation amount Es and the pump flow rate Qp. The slewing body 3 rotates stably even without the operator making fine adjustments to the operating device 8.

[0110] During the period from time t1 to time t2, the required flow rate Qra for the first swing motor is less than the required flow rate Qrs for the second swing motor, and the hydraulic fluid at a pump flow rate Qp calculated based on the detection data (consumption flow rate Qc) of the swing sensor 32 is discharged from the pump 15. In other words, during the period from time t1 to time t2, the swing speed of the swing body 3 is in line with the value of the fourth correlation data, which shows the relationship between the predetermined detection data (consumption flow rate Qc) of the swing sensor 32 and the assist flow rate Qa. The swing body 3 swings at an appropriate swing speed even without the operator making fine adjustments to the control device 8.

[0111] During the period from time t2 to time t3, the required flow rate Qra for the first swing motor is greater than the required flow rate Qrs for the second swing motor, and the hydraulic fluid at a flow rate Qp calculated based on the swing operation amount Es is discharged from the pump 15. In other words, during the period from time t2 to time t3, the swing speed of the swing body 3 is in line with the swing operation amount Es.

[0112] During the period from time t3 onward, the required flow rate Qra for the first swing motor is greater than the required flow rate Qrs for the second swing motor, and the hydraulic fluid at a flow rate Qp calculated based on the time rate of change of the swing operation amount Es and the pump flow rate Qp is discharged from the pump 15. In other words, during the period from time t3 onward, the swing speed of the swing body 3 is in line with the time rate of change of the swing operation amount Es and the pump flow rate Qp.

[0113] As explained with reference to Figure 8, the rate of change of the pump flow rate Qp over time is changed based on the flow rate Qc consumed by the pump 15. When the flow rate Qc consumed by the slewing motor 5 is low, that is, when the slewing speed of the slewing body 3 is low, the rate of change of the pump flow rate Qp over time is low. Therefore, if the operating device 8 is operated to start slewing from a stationary state where the slewing body 3 is not slewing relative to the traveling body 2, for example, the slewing body 3 can start slewing with a low slewing acceleration. In other words, the slewing body 3 can accelerate gradually from a stationary state. As a result, in the low-speed range of slewing speed, the decrease in the stability of the slewing body 3 is suppressed.

[0114] When the flow rate Qc consumed by the slewing motor 5 is high, that is, when the slewing speed of the slewing body 3 is high, the rate of change of the pump flow rate Qp over time is high. For example, if the operating device 8 is operated to move the slewing body 3 from a state where it is slewing at a first slewing speed to a second slewing speed which is higher than the first slewing speed, the slewing body 3 can transition from the state where it is slewing at the first slewing speed to the state where it is slewing at the second slewing speed with high slewing acceleration. In other words, the slewing body 3 can transition from the state where it is slewing at the first slewing speed to the state where it is slewing at the second slewing speed in a short amount of time. As a result, in the high-speed range, the slewing body 3 rotates quickly, thus suppressing a decrease in work efficiency.

[0115] If the slewing sensor 32 malfunctions, it becomes difficult to calculate the first slewing motor's required flow rate Qra. If the slewing sensor 32 malfunctions, the pump flow rate Qp is controlled based on the second slewing motor's required flow rate Qrs calculated from the slewing operation amount Es. As a result, even if the slewing sensor 32 malfunctions, the appropriate flow rate of hydraulic fluid is supplied from the pump 15 to the slewing motor 5, allowing the slewing body 3 to sleave stably.

[0116] This control may not control the pump 15, and may only control the slewing valve 27. Alternatively, the control may be limited to the slewing body 3 and boom 4A.

[0117] [Second Embodiment] A second embodiment will now be described. In the following description, components that are the same as or equivalent to those in the above-described embodiment will be denoted by the same reference numerals, and the descriptions of those components will be simplified or omitted.

[0118] In the first embodiment described above, the control system 13 for standalone slewing operation was explained. In the second embodiment, the control system 13 for combined operation in which the slewing motor 5 and the work machine cylinder 6 are operated simultaneously will be explained. In the second embodiment, the controller 7 acquires a slewing operation amount Es for operating the slewing motor 5 and an work machine operation amount Ew for operating the work machine cylinder 6. Based on the detection data of the slewing sensor 32, the controller 7 calculates a first slewing motor request flow rate Qra, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 to maintain the accelerated state when the slewing speed of the slewing body 3 is in an accelerated state. Based on the slewing operation amount Es, the controller 7 calculates a second slewing motor request flow rate Qrs, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 when the slewing speed of the slewing body 3 is in a steady state during standalone slewing operation. Based on the work machine operation amount Ew, the controller 7 calculates a work machine cylinder request flow rate Qrw, which indicates the flow rate of hydraulic fluid required by the work machine cylinder 6 when the operating speed of the work machine 4 is in a steady state during standalone work machine operation. The controller 7 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15, the opening area of ​​the swivel valve 27, and the opening area of ​​the work machine valve 17, based on the first swivel motor requested flow rate Qra, the second swivel motor requested flow rate Qrs, and the work machine cylinder requested flow rate Qrw.

[0119] <Control in Combined Operation> Figure 11 is a functional block diagram showing the controller 7 according to the second embodiment. In the second embodiment, the controller 7 outputs control commands to control the pump 15, the swivel valve 27, and the work machine valve 17. The input device 9B of the pump pressure sensor 31, the operating device 8, the swivel sensor 32, and the monitor 9 are connected to the controller 7. Based on the swivel operation amount Es of the operating device 8, the work machine operation amount Ew, the detection data of the pump pressure sensor 31, and the detection data of the swivel sensor 32, the controller 7 controls the pump flow rate Qp of the pump 15, the opening area of ​​the swivel valve 27, and the opening area of ​​the work machine valve 17.

[0120] Similar to the first embodiment described above, the controller 7 includes a target swivel speed calculation unit 71, a second swivel motor required flow rate calculation unit 72, a swivel motor consumption flow rate calculation unit 73, a first swivel motor required flow rate calculation unit 74, a selection unit 75, a swivel valve control unit 76, a pump control unit 77, and a storage unit 78. In the second embodiment, the controller 7 includes a swivel motor target flow rate calculation unit 79, a pump upper limit flow rate calculation unit 80, a target operating speed calculation unit 81, a work machine cylinder required flow rate calculation unit 82, a work machine cylinder target flow rate calculation unit 83, and a work machine valve control unit 84.

[0121] Similar to the first embodiment described above, the target rotation speed calculation unit 71 acquires the rotation operation amount Es for operating the rotation motor 5, and calculates the target rotation speed Vrs, which indicates the target value of the rotation speed of the rotation body 3, based on the rotation operation amount Es.

[0122] The second slewing motor required flow rate calculation unit 72 calculates the second slewing motor required flow rate Qrs, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 when the slewing speed of the slewing body 3 is steady state during slewing-only operation, based on the slewing operation amount Es of the operating device 8 or the target slewing speed Vrs.

[0123] The swing motor consumption flow rate calculation unit 73 calculates the consumption flow rate Qc, which indicates the flow rate of the hydraulic fluid passing through the swing motor 5, based on the detection data from the swing sensor 32.

[0124] The first swing motor flow rate calculation unit 74 calculates the first swing motor flow rate Qra, which indicates the flow rate of hydraulic fluid required by the swing motor 5 to maintain the acceleration state in the swing acceleration state, based on the flow rate Qc consumed by the swing motor 5. The first swing motor flow rate calculation unit 74 calculates the first swing motor flow rate Qra based on the fourth correlation data described in Figures 6 and 7, similar to the first embodiment described above. That is, the first swing motor flow rate calculation unit 74 calculates the first swing motor flow rate Qra based on the target swing speed, the flow rate Qc consumed, and the assist flow rate Qa determined from the flow rate Qc consumed.

[0125] In the second embodiment, the required flow rate Qra for the first slewing motor refers to the target value of the flow rate of the hydraulic fluid to be supplied to the slewing motor 5 in order to maintain the accelerated state of the slewing body 3 during the slewing acceleration state.

[0126] As a second method for calculating the first swing motor's required flow rate Qra, the first swing motor's required flow rate Qra may be calculated based on the second swing motor's required flow rate Qrs and the swing load pressure. The first swing motor's required flow rate Qra is calculated by applying, for example, a low-pass filter to the second swing motor's required flow rate Qrs. The cutoff frequency of the low-pass filter is determined so that the cutoff frequency decreases as the swing load pressure increases. The first swing motor's required flow rate Qra may be calculated so that the rate of change of the first swing motor's required flow rate Qra decreases as the swing load pressure increases. In addition, the swing load pressure may be substituted with the pump pressure.

[0127] The selection unit 75 selects the smaller of the first swing motor required flow rate Qra and the swing motor target flow rate Qts.

[0128] The target operating speed calculation unit 81 obtains the work machine operation amount Ew for operating the work machine cylinder 6 from the operating device 8. Based on the work machine operation amount Ew from the operating device 8, the target operating speed calculation unit 81 calculates the target operating speed Vrw, which indicates the target value of the operating speed of the work machine 4. In this embodiment, the target operating speed Vrw is a value proportional to the work machine operation amount Ew. The larger the work machine operation amount Ew, the higher the target operating speed Vrw. If a seventh correlation data showing the relationship between the work machine operation amount Ew and the target operating speed Vrw is predetermined, the target operating speed calculation unit 81 may calculate the target operating speed Vrw by inputting the work machine operation amount Ew into the seventh correlation data.

[0129] The operating speed of the work implement 4 (target operating speed Vrw) and the cylinder speed of the work implement cylinder 6 (target cylinder speed) correspond one-to-one. Calculating the target operating speed Vrw of the work implement 4 may also be considered a concept that includes calculating the target cylinder speed of the work implement cylinder 6. The cylinder speed of the work implement cylinder 6 refers to the speed at which the piston (rod) moves relative to the cylinder tube when the work implement cylinder 6 extends or retracts.

[0130] The work machine cylinder flow rate calculation unit 82 calculates the work machine cylinder flow rate Qrw, which indicates the flow rate of hydraulic fluid required by the work machine cylinder 6, based on the work machine operation amount Ew of the operating device 8. In this embodiment, the work machine cylinder flow rate calculation unit 82 calculates the work machine cylinder flow rate Qrw based on the target operating speed Vrw calculated from the work machine operation amount Ew.

[0131] The required flow rate Qrw for the work machine cylinder refers to the required flow rate of hydraulic fluid required by the work machine cylinder 6 when the work machine 4 is operating at a steady state during standalone operation. A steady state of operation of the work machine 4 means that the operating speed of the work machine 4 is constant (non-accelerating state). In other words, the required flow rate Qrw for the work machine cylinder refers to the required flow rate of the work machine cylinder 6 when the work machine operation amount Ew is constant. In this embodiment, the required flow rate Qrw for the work machine cylinder is a value proportional to the work machine operation amount Ew (or target operating speed Vrw). The larger the work machine operation amount Ew, the greater the required flow rate Qrw for the work machine cylinder. If an eighth correlation data showing the relationship between the work machine operation amount Ew and the required flow rate Qrw for the work machine cylinder is predetermined, the required flow rate calculation unit 82 may calculate the required flow rate Qrw for the work machine cylinder by inputting the work machine operation amount Ew into the eighth correlation data.

[0132] As described above, there is a one-to-one correspondence between the operating speed of the work implement 4 and the cylinder speed of the work implement cylinder 6. The required flow rate Qrw for the work implement cylinder may also be a concept that includes the required flow rate of hydraulic fluid required by the work implement cylinder 6 in a steady state where the cylinder speed of the work implement cylinder 6 is constant.

[0133] The pump upper limit flow rate calculation unit 80 calculates the upper limit flow rate Qmp, which indicates the upper limit of the flow rate of the hydraulic fluid discharged from the pump 15, based on the detection data from the pump pressure sensor 31 and the hardware characteristics of the pump 15. The pump 15 has an upper limit flow rate Qmp that corresponds to the hardware characteristics (pump capacity) of the pump 15. The hardware characteristics of the pump 15 are known data derived from the specifications data or design data of the pump 15. Furthermore, the upper limit flow rate Qmp changes based on the pump pressure, which indicates the pressure of the hydraulic fluid discharged from the pump 15. The pump upper limit flow rate calculation unit 80 can calculate the upper limit flow rate Qmp of the pump 15 based on the detection data from the pump pressure sensor 31 and the hardware characteristics of the pump 15.

[0134] The slewing motor target flow rate calculation unit 79 calculates the slewing motor target flow rate Qts based on the upper limit flow rate Qmp of the pump 15, the second slewing motor required flow rate Qrs, and the work machine cylinder required flow rate Qrw.

[0135] The work machine cylinder target flow rate calculation unit 83 calculates the work machine cylinder target flow rate Qtw based on the upper limit flow rate Qmp of the pump 15, the first swing motor required flow rate Qra, the second swing motor required flow rate Qrs, and the work machine cylinder required flow rate Qrw. In a combined operation, the work machine cylinder target flow rate Qtw in the swing acceleration state and the work machine cylinder target flow rate Qtw in the swing steady state are calculated separately.

[0136] When the target flow rate Qts for the swing motor is selected in the selection unit 75, it means that the swing is in a steady state. The work machine cylinder target flow rate calculation unit 83 calculates the target flow rate Qtw for the work machine cylinder in the steady state of swing based on the upper limit flow rate Qmp of the pump 15, the requested flow rate Qrs for the second swing motor, and the requested flow rate Qrw for the work machine cylinder.

[0137] If the sum of the second slewing motor's requested flow rate Qrs and the work machine cylinder's requested flow rate Qrw exceeds the upper limit flow rate Qmp, the work machine cylinder's target flow rate calculation unit 83 calculates the work machine cylinder's target flow rate Qtw in the steady-state slewing state so that the sum of the slewing motor's target flow rate Qts and the work machine cylinder's target flow rate Qtw becomes equal to the upper limit flow rate Qmp. If the sum of the second slewing motor's requested flow rate Qrs and the work machine cylinder's requested flow rate Qrw exceeds the upper limit flow rate Qmp, the slewing motor's target flow rate calculation unit 79 calculates the slewing motor's target flow rate Qts so that the sum of the slewing motor's target flow rate Qts and the work machine cylinder's target flow rate Qtw in the steady-state slewing state becomes equal to the upper limit flow rate Qmp.

[0138] If the sum of the second slewing motor's required flow rate Qrs and the work machine cylinder's required flow rate Qrw exceeds the upper limit flow rate Qmp, the slewing motor's target flow rate Qts and the work machine cylinder's target flow rate Qtw in the steady-state slewing state may be calculated such that the sum of the slewing motor's target flow rate Qts and the work machine cylinder's target flow rate Qtw does not exceed the upper limit flow rate Qmp.

[0139] On the other hand, if the sum of the second swing motor's required flow rate Qrs and the work machine cylinder's required flow rate Qrw does not exceed the upper limit flow rate Qmp, the swing motor's target flow rate Qts is determined to be the second swing motor's required flow rate Qrs. The work machine cylinder's target flow rate Qtw in the steady-state swing is determined to be the work machine cylinder's required flow rate Qrw.

[0140] When the first swing motor requested flow rate Qra is selected in the selection unit 75, it means that the swing acceleration state is entered.

[0141] The work machine cylinder target flow rate calculation unit 83 calculates the work machine cylinder target flow rate Qtw in the swing acceleration state based on the upper limit flow rate Qmp of the pump 15, the first swing motor required flow rate Qra, and the work machine cylinder required flow rate Qrw.

[0142] If the sum of the first swing motor's requested flow rate Qra and the work machine cylinder's requested flow rate Qrw exceeds the upper limit flow rate Qmp, the work machine cylinder's target flow rate Qtw in the swing acceleration state is calculated so that the sum of the first swing motor's requested flow rate Qra and the work machine cylinder's target flow rate Qtw is equal to the upper limit flow rate Qmp. The work machine cylinder's target flow rate Qtw in the swing acceleration state may also be calculated so that the sum of the first swing motor's requested flow rate Qra and the work machine cylinder's target flow rate Qtw does not exceed the upper limit flow rate Qmp.

[0143] On the other hand, if the sum of the first swing motor's required flow rate Qra and the work machine cylinder's required flow rate Qrw does not exceed the upper limit flow rate Qmp, the work machine cylinder's target flow rate Qtw in the swing acceleration state is determined to be the work machine cylinder's required flow rate Qrw.

[0144] In this embodiment, the target flow rate Qtw of the hydraulic fluid refers to the target value of the hydraulic fluid flow rate to be supplied to each of the multiple actuators, calculated in a combined operation, taking into account the upper limit flow rate Qmp of the pump 15. As described above, the target flow rate Qtw of the work machine cylinder is calculated so that the sum of the smaller of the first swing motor required flow rate Qra and the swing motor target flow rate Qts, and the target flow rate Qtw of the work machine cylinder, does not exceed the upper limit flow rate Qmp.

[0145] In this embodiment, the target flow rate Qts for the swing motor refers to the target value of the flow rate of the hydraulic fluid to be supplied to the swing motor in the steady-state swing state during combined operation, calculated taking into account the upper limit flow rate Qmp of the pump 15. As described above, the target flow rate Qts for the swing motor is calculated so that the sum of the target flow rate Qts for the swing motor and the target flow rate Qtw for the work machine cylinder does not exceed the upper limit flow rate Qmp.

[0146] As described above, in the embodiment, the required flow rate Qra for the first swing motor refers to the target flow rate of the hydraulic fluid to be supplied to the swing motor 5 in order to maintain the acceleration state of the swing body 3 during the swing acceleration state in the combined operation, calculated taking into consideration the upper limit flow rate Qmp of the pump 15.

[0147] The swivel valve control unit 76 controls the opening area of ​​the swivel valve 27 based on the swivel motor target flow rate Qts calculated by the swivel motor target flow rate calculation unit 79. In other words, regardless of whether it is in a swivel acceleration state or a steady state, the opening area of ​​the swivel valve 27 is controlled based on the target value of the flow rate of hydraulic fluid to be supplied to the swivel motor in the swivel steady state.

[0148] The swivel valve control unit 76 controls the opening area of ​​the swivel valve 27 so that it becomes a target opening area calculated based on the target flow rate Qts of the swivel motor. In this embodiment, the swivel valve control unit 76 calculates the target opening area of ​​the swivel valve 27 based on the target flow rate Qts of the swivel motor and a calculation formula (for example, Bernoulli's theorem). The larger the target flow rate Qts of the swivel motor, the larger the target opening area of ​​the swivel valve 27 becomes. The swivel valve control unit 76 controls the swivel valve 27 so that its opening area becomes the target opening area.

[0149] The swivel valve control unit 76 may calculate the target opening area of ​​the swivel valve 27 by multiplying the target flow rate Qts of the swivel motor by a predetermined positive proportionality constant. If correlation data (15th correlation data) showing the relationship between the target flow rate Qts of the swivel motor and the target opening area of ​​the swivel valve 27 is predetermined, the swivel valve control unit 76 may calculate the target opening area of ​​the swivel valve 27 by inputting the target flow rate Qts of the swivel motor into the correlation data showing the relationship between the target flow rate Qts of the swivel motor and the target opening area of ​​the swivel valve 27.

[0150] The swivel valve control unit 76 may also calculate the target opening area of ​​the swivel valve 27 based on the adjusted target flow rate Qts of the swivel motor, by multiplying the target flow rate Qts of the swivel motor by an adjustment gain calculated based on the input data from the input device 9B. The swivel valve control unit 76 acquires the input data from the input device 9B and determines the adjustment gain based on the input data. The adjustment gain for adjusting the target flow rate Qts of the swivel motor may also be set to an arbitrary value by the operator. The swivel valve control unit 76 controls the opening area of ​​the swivel valve 27 based on the target opening area of ​​the swivel valve 27 calculated based on the adjusted target flow rate Qts of the swivel motor.

[0151] Furthermore, the target opening area of ​​the swivel valve 27 may be adjusted by multiplying it by an adjustment gain calculated based on the input data from the input device 9B. The swivel valve control unit 76 acquires the input data from the input device 9B and determines the adjustment gain based on the input data. In addition, the operator may set the adjustment gain for adjusting the target opening area of ​​the swivel valve 27 to an arbitrary value. The swivel valve control unit 76 controls the opening area of ​​the swivel valve 27 based on the adjusted target opening area of ​​the swivel valve 27.

[0152] By inputting data into the input device 9B, the operator can change the speed characteristics during combined operations to their preferred characteristics. An example of speed characteristics is the speed ratio between the slewing speed of the slewing body 3 and the speed of the work machine cylinder.

[0153] The work machine valve control unit 84 controls the opening area of ​​the work machine valve 17 based on the work machine cylinder target flow rate Qtw in the turning acceleration state or the work machine cylinder target flow rate Qtw in the turning steady state, which is calculated by the work machine cylinder target flow rate calculation unit 83.

[0154] If the first swing motor required flow rate Qra is selected in the selection unit 75, the opening area of ​​the work equipment valve 17 is controlled based on the target flow rate Qtw of the work equipment cylinder in the swing acceleration state. If the swing motor target flow rate Qts is selected in the selection unit 75, the opening area of ​​the work equipment valve 17 is controlled based on the target flow rate Qtw of the work equipment cylinder in the swing steady state.

[0155] The work machine valve control unit 84 controls the opening area of ​​the work machine valve 17 so that the work machine cylinder 6 is supplied with hydraulic fluid at a target flow rate Qtw. In this embodiment, the work machine valve control unit 84 calculates the target opening area of ​​the work machine valve 17 based on the target flow rate Qtw and a calculation formula (for example, Bernoulli's theorem). The higher the target flow rate Qtw of the work machine cylinder, the larger the target opening area of ​​the work machine valve 17. The work machine valve control unit 84 controls the work machine valve 17 so that its opening area becomes the target opening area.

[0156] The work machine valve control unit 84 may calculate the target opening area of ​​the work machine valve 17 by multiplying the target flow rate Qtw of the work machine cylinder by a predetermined positive proportionality coefficient.

[0157] If correlation data (16th correlation data) showing the relationship between the target flow rate Qtw of the work machine cylinder and the target opening area of ​​the work machine valve 17 is predetermined, the work machine valve control unit 84 may calculate the target opening area of ​​the work machine valve 17 by inputting the target flow rate Qtw of the work machine cylinder into the correlation data showing the relationship between the target flow rate Qtw of the work machine cylinder and the target opening area of ​​the work machine valve 17.

[0158] The work equipment valve control unit 84 may multiply the work equipment cylinder target flow rate Qtw by an adjustment gain calculated based on the input data from the input device 9B, and calculate the target opening area of ​​the work equipment valve 17 based on the adjusted work equipment cylinder target flow rate Qtw. The swivel valve control unit 76 acquires input data from the input device 9B and determines the adjustment gain based on the input data. The operator may also set the adjustment gain for adjusting the work equipment cylinder target flow rate Qtw to an arbitrary value. The work equipment valve control unit 84 controls the opening area of ​​the work equipment valve 17 based on the target opening area of ​​the work equipment valve 17 calculated based on the adjusted work equipment cylinder target flow rate Qtw.

[0159] Furthermore, the target opening area of ​​the work equipment valve 17 may be adjusted by multiplying it by an adjustment gain calculated based on the input data from the input device 9B. The work equipment valve control unit 84 acquires the input data from the input device 9B and determines the adjustment gain based on the input data. In addition, the operator may set the adjustment gain for adjusting the target opening area of ​​the work equipment valve 17 to an arbitrary value. The work equipment valve control unit 84 controls the opening area of ​​the work equipment valve 17 based on the adjusted target opening area of ​​the work equipment valve 17.

[0160] By inputting data into the input device 9B, the operator can change the speed characteristics during combined operations to their preferred characteristics. An example of speed characteristics is the speed ratio between the slewing speed of the slewing body 3 and the speed of the work machine cylinder.

[0161] The pump control unit 77 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15. The pump control unit 77 calculates the sum of the flow rate selected by the selection unit 75 (the smaller of the first swing motor required flow rate Qra and the swing motor target flow rate Qts) and the work machine cylinder target flow rate Qtw, and controls the pump flow rate Qp based on the sum. The pump control unit 77 controls the swash plate of the pump 15 so that the pump flow rate Qp becomes the sum of the swing motor target flow rate Qts and the work machine cylinder target flow rate Qtw. In other words, the pump control unit 77 controls the pump 15 so that the sum of the flow rate selected by the selection unit 75 and the work machine cylinder target flow rate Qtw is discharged from the pump 15.

[0162] As described above, when the first swing motor requested flow rate Qra is selected in the selection unit 75, that is, when the first swing motor requested flow rate Qra is less than the swing motor target flow rate Qts, it means that the swing acceleration state is entered.

[0163] In the swing acceleration state, if the sum of the flow rate Qra requested by the first swing motor and the flow rate Qrw requested by the work machine cylinder does not exceed the upper limit flow rate Qmp, the target flow rate Qtw of the work machine cylinder becomes equal to the flow rate Qrw requested by the work machine cylinder. Therefore, the pump 15 is controlled so that the sum of the flow rate Qra requested by the first swing motor and the flow rate Qrw requested by the work machine cylinder is discharged from the pump 15.

[0164] On the other hand, in the turning acceleration state, if the sum of the flow rate Qra requested by the first turning motor and the flow rate Qrw requested by the work machine cylinder exceeds the upper limit flow rate Qmp, the sum of the flow rate Qra requested by the first turning motor and the target flow rate Qtw of the work machine cylinder becomes equal to the upper limit flow rate Qmp. Therefore, the pump 15 is controlled so that the upper limit flow rate Qmp is discharged from the pump 15.

[0165] <Calculation Method for Target Flow Rate of Swivel Motor and Target Flow Rate of Work Machine Cylinder> Next, the calculation method for the target flow rate Qts of the swivel motor and the target flow rate Qtw of the work machine cylinder will be explained.

[0166] If the selection unit 75 selects the target flow rate Qts for the swing motor, and the sum of the requested flow rate Qrs for the second swing motor and the requested flow rate Qrw for the work machine cylinder is less than or equal to the upper limit flow rate Qmp, then the target flow rate Qts for the swing motor is determined to be the requested flow rate Qrs for the second swing motor, and the target flow rate Qtw for the work machine cylinder is determined to be the requested flow rate Qrw for the work machine cylinder.

[0167] If the selection unit 75 selects the target flow rate Qts for the swing motor, and the sum of the requested flow rate Qrs for the second swing motor and the requested flow rate Qrw for the work machine cylinder exceeds the upper limit flow rate Qmp, the target flow rate Qts for the swing motor and the target flow rate Qtw for the work machine cylinder are calculated such that the sum of the target flow rate Qts for the swing motor and the target flow rate Qtw for the work machine cylinder does not exceed the upper limit flow rate Qmp, and the ratio of the target flow rate Qts for the swing motor to the target flow rate Qtw for the work machine cylinder matches the ratio of the requested flow rate Qrs for the second swing motor to the requested flow rate Qrw for the work machine cylinder.

[0168] For example, if the upper limit flow rate Qmp is 300 [L / min], the required flow rate Qrs for the second swing motor is 120 [L / min], and the required flow rate Qrw for the work machine cylinder is 60 [L / min], then the sum of the required flow rate Qrs for the second swing motor and the required flow rate Qrw for the work machine cylinder is 180 [L / min], which is less than or equal to 300 [L / min]. In this case, the target flow rate Qts for the swing motor is determined to be 120 [L / min], and the target flow rate Qtw for the work machine cylinder is determined to be 60 [L / min].

[0169] For example, if the upper limit flow rate Qmp is 300 [L / min], the second swing motor's required flow rate Qrs is 400 [L / min], and the work machine cylinder's required flow rate Qrw is 200 [L / min], the sum of the second swing motor's required flow rate Qrs and the work machine cylinder's required flow rate Qrw is 600 [L / min], which exceeds 300 [L / min]. In this case, the swing motor's target flow rate Qts and the work machine cylinder's target flow rate Qtw are calculated so that the sum of the swing motor's target flow rate Qts and the work machine cylinder's target flow rate Qtw does not exceed the upper limit flow rate Qmp, and the ratio of the swing motor's target flow rate Qts to the work machine cylinder's target flow rate Qtw matches the ratio of the second swing motor's required flow rate Qrs to the work machine cylinder's required flow rate Qrw. Since the ratio of the required flow rate Qrs for the second swing motor to the required flow rate Qrw for the work machine cylinder is [400:200] (= [2:1]), the ratio of the target flow rate Qts for the swing motor to the target flow rate Qtw for the work machine cylinder is determined to be [2:1]. That is, the target flow rate Qts for the swing motor is determined to be 200 [L / min], and the target flow rate Qtw for the work machine cylinder is determined to be 100 [L / min].

[0170] If the first swing motor required flow rate Qra is selected in the selection unit 75, and the sum of the first swing motor required flow rate Qra and the work machine cylinder required flow rate Qrw is less than or equal to the upper limit flow rate Qmp, the work machine cylinder target flow rate Qtw is determined to be the work machine cylinder required flow rate Qrw.

[0171] If the first swing motor required flow rate Qra is selected in the selection unit 75, and the sum of the first swing motor required flow rate Qra and the work machine cylinder required flow rate Qrw exceeds the upper limit flow rate Qmp, the work machine cylinder target flow rate Qtw is calculated so that the sum of the first swing motor required flow rate Qra and the work machine cylinder target flow rate Qtw does not exceed the upper limit flow rate Qmp.

[0172] When there are two or more required flow rates Qrw for the work equipment cylinders, for example, when operating two or more work equipment simultaneously, such as a boom, arm, and bucket, the target flow rates Qtw for each of the work equipment cylinders are calculated such that the ratio between the target flow rates Qtw for each of the work equipment cylinders matches the ratio between the required flow rates Qrw for each of the work equipment cylinders. For example, when operating the boom and arm simultaneously, the target flow rates for the boom cylinder and the target flow rates for the arm cylinder are calculated such that the ratio between the target flow rate for the boom cylinder and the target flow rate for the arm cylinder matches the ratio between the required flow rate for the boom cylinder and the required flow rate for the arm cylinder.

[0173] Figure 12 is a diagram showing the relationship between the second swing motor's required flow rate Qrs, the work machine cylinder's required flow rate Qrw, and the swing motor's target flow rate Qts according to the second embodiment. In the graph of Figure 12, the horizontal axis represents time, and the vertical axis represents the flow rate of the hydraulic fluid. Line Lrs represents the second swing motor's required flow rate Qrs. Line Lrw1 represents the boom cylinder's required flow rate Qrw1. Line Lrw2 represents the arm cylinder's required flow rate Qrw2. The work machine cylinder's required flow rate Qrw is the sum of the boom cylinder's required flow rate Qrw1 and the arm cylinder's required flow rate Qrw2. Line Lts represents the swing motor's target flow rate Qts.

[0174] In the graph of Figure 12, during the period from time 0 to time t4 (after time 0), the working machine cylinder 6 does not require hydraulic fluid, so the second slewing motor required flow rate Qrs and the slewing motor target flow rate Qts are the same value. During the period from time t4 to time t5, as the boom cylinder required flow rate Qrw1 increases, the slewing motor target flow rate Qts decreases so that the sum of the slewing motor target flow rate Qts and the working machine cylinder target flow rate Qtw does not exceed the upper limit flow rate Qmp. During the period from time t5 onward, the boom cylinder required flow rate Qrw1 becomes constant. During the period from time t6 (after time t5) to time t7 (after time t6), with the boom cylinder required flow rate Qrw1 remaining constant, the arm cylinder required flow rate Qrw2 increases, so the slewing motor target flow rate Qts decreases further so that the sum of the slewing motor target flow rate Qts and the working machine cylinder target flow rate Qtw does not exceed the upper limit flow rate Qmp.

[0175] As shown in Figure 12, if the sum of the flow rate Qrs requested by the second swivel motor and the flow rate Qrw requested by the work machine cylinder exceeds the upper limit flow rate Qmp of the pump 15, the opening area of ​​the swivel valve 27 is controlled to decrease as the flow rate Qrw requested by the work machine cylinder increases.

[0176] Furthermore, if the sum of the flow rate Qrs requested by the second swivel motor and the flow rate Qrw requested by the work machine cylinder exceeds the upper limit flow rate Qmp of the pump 15, the opening area of ​​the work machine valve 17 is controlled to decrease as the flow rate Qrs requested by the second swivel motor increases.

[0177] Figure 13 is a diagram illustrating the relationship between the upper limit flow rate Qmp of the pump 15 according to the second embodiment, the boom cylinder required flow rate Qrw1, the arm cylinder required flow rate Qrw2, the boom cylinder target flow rate Qtw1, the arm cylinder target flow rate Qtw2, and the second slewing motor required flow rate Qrs.

[0178] In the graph of Figure 13, the horizontal axis represents time, and the vertical axis represents the flow rate of the hydraulic fluid. Line Lmp indicates the upper limit flow rate Qmp of pump 15. Line Lrw1 indicates the boom cylinder required flow rate Qrw1. Line Lrw2 indicates the arm cylinder required flow rate Qrw2. Line Ltw1 indicates the boom cylinder target flow rate Qtw1. Line Ltw2 indicates the arm cylinder target flow rate Qtw2. Line Lra indicates the first slewing motor required flow rate Qra. The work machine cylinder required flow rate Qrw is the sum of the boom cylinder required flow rate Qrw1 and the arm cylinder required flow rate Qrw2. The work machine cylinder target flow rate Qtw is the sum of the boom cylinder target flow rate Qtw1 and the arm cylinder target flow rate Qtw2.

[0179] During the period from time 0 to time t8, which is after time 0, the boom cylinder 6A and arm cylinder 6B require hydraulic fluid, while the slewing motor 5 does not. Therefore, the boom cylinder target flow rate Qtw1 and arm cylinder target flow rate Qtw2 are calculated such that the work machine cylinder required flow rate Qrw, which is the sum of the boom cylinder required flow rate Qrw1 and the arm cylinder required flow rate Qrw2, does not exceed the upper limit flow rate Qmp, and the ratio of the boom cylinder target flow rate Qtw1 to the arm cylinder target flow rate Qtw2 matches the ratio of the boom cylinder required flow rate Qrw1 to the arm cylinder required flow rate Qrw2.

[0180] During the period from time t8 to time t9 (which is after time t8), the first swing motor's requested flow rate Qra increases. Furthermore, during the period from time t9 onward, the first swing motor's requested flow rate Qra becomes constant. From time t8 onward, the target flow rate Qtw for the working cylinder is calculated such that the sum of the swing motor's target flow rate Qts and the working cylinder's target flow rate Qtw does not exceed the upper limit flow rate Qmp, and the ratio between the working cylinder's target flow rates Qtw matches the ratio between the working cylinder's requested flow rates Qrw.

[0181] Figure 14 is a diagram illustrating the relationship between the upper limit flow rate Qmp of the pump 15 according to the second embodiment, the required flow rate Qrw of the work machine cylinder, the target flow rate Qtw of the work machine cylinder, the required flow rate Qra of the first swing motor, and the target flow rate Qts of the swing motor.

[0182] In the graph of Figure 14, the horizontal axis represents time, and the vertical axis represents the flow rate of the hydraulic fluid. Line Lmp indicates the upper limit flow rate Qmp of pump 15. Line Lrw indicates the required flow rate Qrw for the work machine cylinder. Line Ltw indicates the target flow rate Qtw for the work machine cylinder. Line Lrs indicates the required flow rate Qrs for the second swing motor. Line Lts indicates the target flow rate Qts for the swing motor. Line Lra indicates the required flow rate Qra for the first swing motor.

[0183] At time 0, the requested flow rate Qrs for the second slewing motor is greater than 0. At time t10, which is after time 0, the acceleration of the slewing speed of the slewing body 3 begins. During the period from time t10 to time t11, which is after time t10, the requested flow rate Qrw for the work machine cylinder increases, and at time t11, the requested flow rate Qrw for the work machine cylinder exceeds the upper limit flow rate Qmp of the pump 15.

[0184] During the period from time 0 to time t11, the first swing motor's requested flow rate Qra is zero. Since the first swing motor's requested flow rate Qra is smaller than the second swing motor's requested flow rate Qrs, the selection unit 75 selects the first swing motor's requested flow rate Qra, meaning the swing body 3 is in a swing acceleration state. The swing motor's target flow rate Qts is calculated such that the sum of the swing motor's target flow rate Qts and the work machine cylinder's target flow rate Qtw does not exceed the upper limit flow rate Qmp, and the ratio of the swing motor's target flow rate Qts to the work machine cylinder's target flow rate Qtw in a steady-state swing (not shown) matches the ratio of the second swing motor's requested flow rate Qrs to the work machine cylinder's requested flow rate Qrw.

[0185] At time t11, the first swing motor's requested flow rate Qra is zero. During the period from time t11 to time t12 (which is later than time t11), the first swing motor's requested flow rate Qra increases. During the period from time t11 to time t12, the first swing motor's requested flow rate Qra is smaller than the second swing motor's requested flow rate Qrs, so the selection unit 75 selects the first swing motor's requested flow rate Qra, meaning the swing body 3 is in a swing acceleration state. During the period from time t11 to time t12, if the sum of the first swing motor's requested flow rate Qra and the work machine cylinder's requested flow rate Qrw exceeds the upper limit flow rate Qmp, the work machine cylinder's target flow rate Qtw in the swing acceleration state is calculated so that the sum of the first swing motor's requested flow rate Qra and the work machine cylinder's target flow rate Qtw does not exceed the upper limit flow rate Qmp. For example, the target flow rate Qtw for the work machine cylinder in the slewing acceleration state is calculated by subtracting the first slewing motor's required flow rate Qra from the upper limit flow rate Qmp.

[0186] During the period from time t12 to time t13 after time t12, the selection unit 75 selects the second slewing motor required flow rate Qrs, and the slewing body 3 is in a steady state. During the period from time t12 to time t13, if the sum of the second slewing motor required flow rate Qrs and the work machine cylinder required flow rate Qrw exceeds the upper limit flow rate Qmp, the slewing motor target flow rate Qts and the work machine cylinder target flow rate Qtw are calculated such that the sum of the slewing motor target flow rate Qts and the work machine cylinder target flow rate Qtw does not exceed the upper limit flow rate Qmp, and the ratio of the slewing motor target flow rate Qts to the work machine cylinder target flow rate Qtw matches the ratio of the second slewing motor required flow rate Qrs to the work machine cylinder required flow rate Qrw.

[0187] <Effects> As explained above, in combined operation, the controller 7 acquires the slewing operation amount Es for operating the slewing motor 5 and the work equipment operation amount Ew for operating the work equipment cylinder 6. Based on the detection data of the slewing sensor 32, the controller 7 calculates the first slewing motor required flow rate Qra, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 to maintain the accelerated state when the slewing speed of the slewing body 3 is in an accelerated state. Based on the slewing operation amount Es, the controller 7 calculates the second slewing motor required flow rate Qrs, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 when the slewing speed of the slewing body 3 is in a steady state. Based on the work equipment operation amount Ew, the controller 7 calculates the work equipment cylinder required flow rate Qrw, which indicates the flow rate of hydraulic fluid required by the work equipment cylinder 6 when the operating speed of the work equipment 4 is in a steady state. The controller 7 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15, the opening area of ​​the swivel valve 27, and the opening area of ​​the work machine valve 17, based on the first swivel motor requested flow rate Qra, the second swivel motor requested flow rate Qrs, and the work machine cylinder requested flow rate Qrw.

[0188] According to the embodiment, in combined operation, the controller 7 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15, the opening area of ​​the slewing valve 27, and the opening area of ​​the work machine valve 17, based on the first slewing motor required flow rate Qra, the second slewing motor required flow rate Qrs, and the work machine cylinder required flow rate Qrw. As a result, the pump 15 supplies hydraulic fluid at an appropriate flow rate to both the slewing motor 5 and the work machine cylinder 6. Since the pump 15 supplies hydraulic fluid at an appropriate flow rate to both the slewing motor 5 and the work machine cylinder 6, the slewing body 3 can slewing stably, and the work machine 4 can operate stably.

[0189] In the swing acceleration state, if the sum of the first swing motor's requested flow rate Qra and the work machine cylinder's target flow rate Qtw is less than or equal to the upper limit flow rate Qmp, the pump supplies a flow rate to the swing motor that maintains the acceleration state of the swing speed, as indicated by the first swing motor's requested flow rate Qra. If the sum of the first swing motor's requested flow rate Qra and the work machine cylinder's target flow rate Qtw is greater than or equal to the upper limit flow rate Qmp, that is, if the pump supplies a flow rate equal to the upper limit flow rate Qmp, the larger the first swing motor's requested flow rate Qra, the smaller the work machine cylinder's target flow rate Qtw becomes, and therefore the pump supplies a flow rate to the swing motor that maintains the acceleration state of the swing speed. As a result, the swing body 3 can swing stably during swing acceleration.

[0190] In a steady-state rotation, if the sum of the second rotation motor's requested flow rate Qrs and the work machine cylinder's target flow rate Qtw is less than the upper limit flow rate Qmp, the flow rate required to maintain a steady rotation speed is supplied from the pump to the rotation motor, equal to the second rotation motor's requested flow rate Qrs. If the sum of the second rotation motor's requested flow rate Qrs and the work machine cylinder's target flow rate Qtw is equal to or greater than the upper limit flow rate Qmp, that is, if the pump supplies a flow rate equal to the upper limit flow rate Qmp, the flow rates supplied from the pump to the rotation motor and the work machine cylinder are the same ratio as the ratio of the second rotation motor's requested flow rate Qrs and the work machine cylinder's requested flow rate Qrw. As a result, the rotation body 3 can rotate stably during combined operation, and the work machine 4 can operate stably.

[0191] In the above-described embodiment, only the work equipment valve 17 and the slewing valve 27 are controlled, and the pump 15 does not need to be electronically controlled. The objects of operation may also be limited to only the slewing body 3 and the boom 4A.

[0192] [Third Embodiment] A third embodiment will now be described. In the following description, components that are the same as or equivalent to those in the above-described embodiments will be denoted by the same reference numerals, and the descriptions of those components will be simplified or omitted.

[0193] In the third embodiment, the controller 7 corrects the opening area of ​​the swivel valve 27 based on the data detected by the load pressure sensor 33. The controller 7 corrects the opening area of ​​the work machine valve 17 based on the data detected by the load pressure sensor 33.

[0194] <Control in Combined Operation> Figure 15 is a functional block diagram showing a controller 7 according to the third embodiment. In the third embodiment, the controller 7 outputs control commands to control the pump 15, the swivel valve 27, and the work machine valve 17. A load pressure sensor 33 and an operating device 8 are connected to the controller 7. Based on the swivel operation amount Es of the operating device 8, the work machine operation amount Ew, and the detection data of the load pressure sensor 33, the controller 7 controls the pump flow rate Qp of the pump 15, the opening area of ​​the swivel valve 27, and the opening area of ​​the work machine valve 17.

[0195] Similar to the second embodiment described above, the controller 7 includes a target swivel speed calculation unit 71, a second swivel motor required flow rate calculation unit 72, a target operating speed calculation unit 81, a work machine cylinder required flow rate calculation unit 82, a work machine cylinder target flow rate calculation unit 83, a swivel valve control unit 76, a pump control unit 77, and a work machine valve control unit 84.

[0196] The target rotation speed calculation unit 71 acquires the rotation operation amount Es for operating the rotation motor 5, and calculates the target rotation speed Vrs, which indicates the target value of the rotation speed of the rotation body 3, based on the rotation operation amount Es. The target rotation speed calculation unit 71 calculates the target rotation speed Vrs during rotation-only operation based on the rotation operation amount Es. The target rotation speed Vrs during rotation-only operation may be a value proportional to the rotation operation amount Es. The larger the rotation operation amount Es, the higher the target rotation speed Vrs during rotation-only operation. If a ninth correlation data showing the relationship between the rotation operation amount Es and the target rotation speed Vrs during rotation-only operation is predetermined, the target rotation speed calculation unit 71 may calculate the target rotation speed Vrs during rotation-only operation by inputting the rotation operation amount Es into the ninth correlation data.

[0197] The second slewing motor flow rate calculation unit 72 calculates the second slewing motor flow rate Qrs, which indicates the flow rate of hydraulic fluid required by the slewing motor 5 when the slewing speed of the slewing body 3 is in a steady state, based on the slewing operation amount Es of the operating device 8 or the target slewing speed Vrs. The second slewing motor flow rate calculation unit 72 also calculates the second slewing motor flow rate Qrs during slewing-only operation based on the target slewing speed Vrs during slewing-only operation.

[0198] The target operating speed calculation unit 81 acquires the implement operation amount Ew for operating the implement cylinder 6, and calculates the target operating speed Vrw, which indicates the target value of the operating speed of the implement 4, based on the implement operation amount Ew. The target operating speed calculation unit 81 calculates the target operating speed Vrw when the implement is operated alone, based on the implement operation amount Ew. The target operating speed Vrw when the implement is operated alone may be a value proportional to the implement operation amount Ew. The larger the implement operation amount Ew, the higher the target operating speed Vrw when the implement is operated alone. If 11th correlation data showing the relationship between the implement operation amount Ew and the target operating speed Vrw when the implement is operated alone is predetermined, the target operating speed calculation unit 81 may calculate the target operating speed Vrw when the implement is operated alone by inputting the implement operation amount Ew into the 11th correlation data.

[0199] The work machine cylinder flow rate calculation unit 82 calculates the work machine cylinder flow rate Qrw, which indicates the flow rate of hydraulic fluid required by the work machine cylinder 6 when the operating speed of the work machine 4 is in a steady state, based on the work machine operation amount Ew of the operating device 8 or the target operating speed Vrw. The work machine cylinder flow rate calculation unit 82 also calculates the work machine cylinder flow rate Qrw when the work machine is operated alone, based on the target operating speed Vrw when the work machine is operated alone.

[0200] The slewing motor target flow rate calculation unit 79 calculates the slewing motor target flow rate Qts by correcting the second slewing motor required flow rate Qrs during slewing-only operation based on the data detected by the load pressure sensor 33. The slewing motor target flow rate calculation unit 79 can determine whether the operating device 8 has been operated in combination based on the slewing operation amount Es and the work machine operation amount Ew. If the slewing motor target flow rate calculation unit 79 determines that the operating device 8 has been operated in combination, it calculates the slewing motor target flow rate Qts by correcting the second slewing motor required flow rate Qrs during slewing-only operation based on the data detected by the load pressure sensor 33. The slewing motor target flow rate Qts for combined operation is a smaller value than the second slewing motor required flow rate Qrs during slewing-only operation.

[0201] The slewing motor target flow rate calculation unit 79 determines, based on the slewing operation amount Es and the work machine operation amount Ew, that the operating device 8 has been operated for slewing alone, and sets the second slewing motor required flow rate Qrs during slewing-only operation as the slewing motor target flow rate Qts.

[0202] The work machine cylinder target flow rate calculation unit 83 calculates the work machine cylinder target flow rate Qtw by correcting the work machine cylinder required flow rate Qrw based on the data detected by the load pressure sensor 33. The work machine cylinder target flow rate calculation unit 83 can determine whether the operating device 8 has been operated in combination based on the slewing operation amount Es and the work machine operation amount Ew. If the work machine cylinder target flow rate calculation unit 83 determines that the operating device 8 has been operated in combination, it calculates the work machine cylinder target flow rate Qtw by correcting the work machine cylinder required flow rate Qrw when the work machine is operated alone, based on the data detected by the load pressure sensor 33. The work machine cylinder target flow rate Qtw is a value greater than the work machine cylinder required flow rate Qrw when the work machine is operated alone.

[0203] When the swivel valve control unit 76 determines that the operating device 8 has been operated in combination, it controls the swivel valve 27 based on the data detected by the load pressure sensor 33 so that the opening area of ​​the swivel valve 27 becomes a modified opening area of ​​the swivel valve 27 that is smaller than the opening area of ​​the swivel valve 27 when the swivel valve 27 is operated in swivel mode alone. When the swivel valve control unit 76 determines that the operating device 8 has been operated in swivel mode alone, it controls the swivel valve 27 so that the opening area of ​​the swivel valve 27 becomes the opening area of ​​the swivel valve 27 when the swivel valve 27 is operated in swivel mode alone.

[0204] In this embodiment, the swivel valve control unit 76 corrects the opening area of ​​the swivel valve 27 by controlling the swivel valve 27 based on the swivel motor target flow rate Qts calculated by taking into account the detection data of the load pressure sensor 33.

[0205] The swivel valve control unit 76 calculates the target opening area of ​​the swivel valve 27 based on the target flow rate Qts of the swivel motor and a calculation formula (for example, Bernoulli's theorem). The higher the target flow rate Qts of the swivel motor, the larger the target opening area of ​​the swivel valve 27. The swivel valve control unit 76 controls the swivel valve 27 so that its opening area becomes the target opening area. The swivel valve control unit 76 may also calculate the target opening area of ​​the swivel valve 27 by multiplying the target flow rate Qts of the swivel motor by a predetermined positive proportionality constant. If correlation data (15th correlation data) showing the relationship between the target flow rate Qts of the swivel motor and the target opening area of ​​the swivel valve 27 is predetermined, the swivel valve control unit 76 may calculate the target opening area of ​​the swivel valve 27 by inputting the target flow rate Qts of the swivel motor into the correlation data showing the relationship between the target flow rate Qts of the swivel motor and the target opening area of ​​the swivel valve 27.

[0206] When the work equipment valve control unit 84 determines that the operating device 8 has been operated in combination, it controls the work equipment valve 17 based on the detection data of the load pressure sensor 33 so that the opening area of ​​the work equipment valve 17 becomes a modified opening area of ​​the work equipment valve 17 that is larger than the opening area of ​​the work equipment valve 17 when the work equipment is operated alone. When the operating device 8 determines that the work equipment has been operated alone, the work equipment valve control unit 84 controls the work equipment valve 17 so that the opening area of ​​the work equipment valve 17 becomes the opening area of ​​the work equipment valve 17 when the work equipment is operated alone.

[0207] In this embodiment, the work machine valve control unit 84 corrects the opening area of ​​the work machine valve 17 by controlling the work machine valve 17 based on the target flow rate Qtw of the work machine cylinder, which is calculated taking into account the detection data of the load pressure sensor 33.

[0208] The work equipment valve control unit 84 calculates the target opening area of ​​the work equipment valve 17 based on the target flow rate Qtw of the work equipment cylinder and a calculation formula (for example, Bernoulli's theorem). The higher the target flow rate Qtw of the work equipment cylinder, the larger the target opening area of ​​the work equipment valve 17. The work equipment valve control unit 84 controls the work equipment valve 17 so that its opening area becomes the target opening area.

[0209] The work machine valve control unit 84 may calculate the target opening area of ​​the work machine valve 17 by multiplying the target flow rate Qtw of the work machine cylinder by a predetermined positive proportionality coefficient.

[0210] If correlation data (16th correlation data) showing the relationship between the target flow rate Qtw of the work machine cylinder and the target opening area of ​​the work machine valve 17 is predetermined, the work machine valve control unit 84 may calculate the target opening area of ​​the work machine valve 17 by inputting the target flow rate Qtw of the work machine cylinder into the correlation data showing the relationship between the target flow rate Qtw of the work machine cylinder and the target opening area of ​​the work machine valve 17.

[0211] The pump control unit 77 controls the pump flow rate Qp, which indicates the flow rate of hydraulic fluid discharged from the pump 15, based on the target flow rate Qts of the slewing motor calculated by the target flow rate calculation unit 79 and the target flow rate Qtw of the work machine cylinder calculated by the work machine cylinder target flow rate calculation unit 83. In combined operation, the pump control unit 77 determines the pump flow rate Qp to be the sum of the target flow rate Qts of the slewing motor and the target flow rate Qtw of the work machine cylinder.

[0212] <Method for Calculating the Modified Opening Area> Next, the method for calculating the modified opening area of ​​the swivel valve 27 and the modified opening area of ​​the work machine valve 17 will be explained.

[0213] The slewing motor target flow rate calculation unit 79 calculates the adjustment gain for the slewing motor target flow rate Qts based on the data detected by the load pressure sensor 33 and the target operating speed Vrw. The slewing motor target flow rate calculation unit 79 calculates the slewing motor target flow rate Qts by multiplying the second slewing motor required flow rate Qrs during slewing-only operation by the adjustment gain. The slewing motor target flow rate calculation unit 79 calculates the adjustment gain for calculating the slewing motor target flow rate Qts based on 13 correlation data in which the adjustment gain decreases as the target operating speed Vrw increases and the adjustment gain decreases as the pressure detected by the load pressure sensor 33 increases.

[0214] The work machine cylinder target flow rate calculation unit 83 calculates the adjustment gain for the work machine cylinder target flow rate Qtw based on the data detected by the load pressure sensor 33 and the target turning speed Vrs. The work machine cylinder target flow rate calculation unit 83 calculates the work machine cylinder target flow rate Qtw by multiplying the work machine cylinder required flow rate Qrw when the work machine is operated alone by the adjustment gain. The work machine cylinder target flow rate calculation unit 83 calculates the adjustment gain for calculating the work machine cylinder target flow rate Qtw based on 14 correlation data in which the adjustment gain increases as the target turning speed Vrs increases and the adjustment gain increases as the pressure detected by the load pressure sensor 33 increases.

[0215] In this embodiment, the swivel valve control unit 76 calculates the target opening area of ​​the swivel valve 27 based on the target flow rate Qts of the swivel motor, which is calculated taking into account the detection data of the load pressure sensor 33, and controls the opening area of ​​the swivel valve 27.

[0216] The work machine valve control unit 84 calculates the target opening area of ​​the work machine valve 17 based on the target flow rate Qtw of the work machine cylinder, which is calculated taking into account the detection data of the load pressure sensor 33, and controls the opening area of ​​the work machine valve 17.

[0217] As a second method for calculating the opening area during combined operation of the swivel valve 27 and the work equipment valve 17, the target opening area of ​​the swivel valve 27 during swivel-only operation may be calculated based on the second swivel motor's required flow rate Qrs or the target swivel speed Vrs during swivel-only operation; the target opening area of ​​the work equipment valve 17 during work equipment-only operation may be calculated based on the work equipment cylinder's required flow rate Qrw or the target operating speed Vrw during work equipment-only operation; an adjustment gain to be multiplied by the target opening area of ​​the swivel valve 27 based on the data detected by the load pressure sensor 33 and the target operating speed Vrw; an adjustment gain to be multiplied by the target opening area of ​​the work equipment valve 17 based on the data detected by the load pressure sensor 33 and the target swivel speed Vrs; and the target opening area during combined operation of the swivel valve 27 and the work equipment valve 17 may be calculated by multiplying each target opening area by the respective adjustment gain.

[0218] In the following description, the adjustment gain for calculating the target flow rate Qts of the slewing motor or the adjustment gain multiplied by the target opening area of ​​the slewing valve 27 will be appropriately referred to as the adjustment gain for calculating the modified opening area of ​​the slewing valve 27. The adjustment gain for calculating the target flow rate Qtw of the work machine cylinder or the adjustment gain multiplied by the target opening area of ​​the work machine valve 17 will be appropriately referred to as the adjustment gain for calculating the modified opening area of ​​the work machine valve 17.

[0219] Figure 16 is a diagram illustrating the 13th and 14th correlation data according to the third embodiment. The upper graph in Figure 16 shows the 13th correlation data for calculating the modified opening area of ​​the swivel valve 27. The lower graph in Figure 16 shows the 14th correlation data for calculating the modified opening area of ​​the work machine valve 17.

[0220] In the upper graph of Figure 16, the horizontal axis represents the meter-in pressure, which indicates the pressure of the hydraulic fluid flowing into the swivel valve 27 as detected by the load pressure sensor 33. The vertical axis represents the adjustment gain for calculating the corrected opening area of ​​the swivel valve 27. In the upper graph of Figure 16, line Lt shows the relationship between the meter-in pressure and the adjustment gain when the target operating speed Vrw of the work implement 4 is zero (work implement operating amount Ew is 0%). Line Lu shows the relationship between the meter-in pressure and the adjustment gain when the target operating speed Vrw of the work implement 4 is a first target operating speed higher than zero (work implement operating amount Ew is, for example, 50%). Line Lu shows the relationship between the meter-in pressure and the adjustment gain when the target operating speed Vrw of the work implement 4 is a second target operating speed higher than the first target operating speed (work implement operating amount Ew is, for example, 100%).

[0221] As shown by line Lt, when the target operating speed Vrw of the implement 4 is zero, the adjustment gain is 1 regardless of the meter-in pressure. When the target operating speed Vrw of the implement 4 is zero, it is determined that the operating device 8 is being operated for rotation only.

[0222] As shown by line Lu, when the target operating speed Vrw of the work implement 4 is the first target operating speed, the adjustment gain is 1 in the range of meter-in pressure from zero to a value P21 higher than zero. In the range of meter-in pressure from value P21 to value P22 higher than P21, the adjustment gain decreases from 1 to a first gain value less than 1. In the range of meter-in pressure higher than value P22, the adjustment gain is the first gain value.

[0223] As shown in line Lv, when the target operating speed Vrw of the work implement 4 is the second target operating speed, the adjustment gain is 1 in the range of meter-in pressure from zero to value P21. In the range of meter-in pressure from value P21 to value P22, the adjustment gain decreases from 1 to a second gain value that is smaller than the first gain value. In the range of meter-in pressure higher than value P22, the adjustment gain is the second gain value.

[0224] The slewing motor target flow rate calculation unit 79 can determine an adjustment gain for calculating the slewing motor target flow rate Qts by inputting the meter-in pressure detected by the load pressure sensor 33 into the 13th correlation data. The slewing motor target flow rate calculation unit 79 calculates the slewing motor target flow rate Qts during combined operation by multiplying the second slewing motor required flow rate Qrs during single operation of the work machine by the adjustment gain. The slewing valve control unit 76 calculates the corrected target opening area of ​​the slewing valve 27 during combined operation based on the slewing motor target flow rate Qts, and controls the slewing valve 27 so that its opening area becomes the corrected target opening area.

[0225] In the range where the meter-in pressure is zero to value P21, the adjustment gain is 1, so the corrected target opening area of ​​the swivel valve 27 is equal to the target opening area of ​​the swivel valve 27 during swivel-only operation. In the range where the meter-in pressure exceeds value P21, the adjustment gain is less than 1, so the corrected target opening area of ​​the swivel valve 27 is smaller than the target opening area of ​​the swivel valve 27 during swivel-only operation.

[0226] In the lower graph of Figure 16, the horizontal axis represents the meter-in pressure, which indicates the pressure of the hydraulic fluid flowing into the swivel valve 27 as detected by the load pressure sensor 33. The vertical axis represents the adjustment gain for calculating the corrected opening area of ​​the work equipment valve 17. In the lower graph of Figure 16, line Lt shows the relationship between the meter-in pressure and the adjustment gain when the target swivel speed Vrs of the swivel body 3 is zero (swivel operation amount Es is 0%). Line Lu shows the relationship between the meter-in pressure and the adjustment gain when the target swivel speed Vrs of the swivel body 3 is a third target swivel speed higher than zero (swivel operation amount Es is, for example, 50%). Line Lu shows the relationship between the meter-in pressure and the adjustment gain when the target swivel speed Vrs of the swivel body 3 is a fourth target swivel speed higher than the third target swivel speed (swivel operation amount Es is, for example, 100%).

[0227] As shown by line Lt, when the target rotation speed Vrs of the slewing body 3 is zero, the adjustment gain is 1 regardless of the meter-in pressure. When the target rotation speed Vrs of the slewing body 3 is zero, the operating device 8 is determined to be operating the work implement independently.

[0228] As shown by line Lu, when the target turning speed Vrs of the rotating body 3 is the third target turning speed, the adjustment gain is 1 in the range of meter-in pressure from zero to a value P11 greater than zero. In the range of meter-in pressure from value P11 to value P12 greater than value P11, the adjustment gain increases from 1 to a third gain value greater than 1. In the range of meter-in pressure greater than value P12, the adjustment gain is the third gain value.

[0229] As shown by line Lv, when the target turning speed Vrs of the rotating body 3 is the fourth target turning speed, the adjustment gain is 1 in the range of meter-in pressure from zero to value P11. In the range of meter-in pressure from value P11 to value P12, the adjustment gain increases from 1 to a fourth gain value greater than the third gain value. In the range of meter-in pressure higher than value P12, the adjustment gain is the fourth gain value.

[0230] The work machine cylinder target flow rate calculation unit 83 can determine an adjustment gain for calculating the work machine cylinder target flow rate Qtw by inputting the meter-in pressure detected by the load pressure sensor 33 into the 14th correlation data. The work machine cylinder target flow rate calculation unit 83 calculates the work machine cylinder target flow rate Qtw during combined operation by multiplying the work machine cylinder required flow rate Qrw during work machine standalone operation by the adjustment gain. The work machine valve control unit 84 calculates the corrected target opening area of ​​the work machine valve 17 during combined operation based on the work machine cylinder target flow rate Qtw, and controls the work machine valve 17 so that its opening area becomes the corrected target opening area.

[0231] In the range where the meter-in pressure is zero to value P11, the adjustment gain is 1, so the corrected target opening area of ​​the implement valve 17 is equal to the target opening area of ​​the implement valve 17 when the implement is operated alone. In the range where the meter-in pressure exceeds value P11, the adjustment gain is greater than 1, so the corrected target opening area of ​​the implement valve 17 is greater than the target opening area of ​​the implement valve 17 when the implement is operated alone.

[0232] <Effects> As described above, in the third embodiment, the target slewing speed Vrs during slewing-only operation is calculated based on the slewing operation amount Es, and the target operating speed Vrw during work equipment-only operation is calculated based on the work equipment operation amount Ew. When the meter-in pressure of the slewing valve 27 detected by the load pressure sensor 33 is high, the slewing valve 27 is controlled so that the opening area of ​​the slewing valve 27 becomes smaller than the opening area of ​​the slewing valve 27 during slewing-only operation, and the work equipment valve 17 is controlled so that the opening area of ​​the work equipment valve 17 becomes larger than the opening area of ​​the work equipment valve 17 during work equipment-only operation. As the meter-in pressure of the slewing valve 27 increases, the opening area of ​​the slewing valve 27 decreases, and the flow rate of hydraulic fluid supplied to the slewing motor 5 decreases, thus suppressing an excessive rise in the meter-in pressure of the slewing valve 27. As the meter-in pressure of the slewing valve 27 increases, the opening area of ​​the work machine valve 17 increases, and the flow rate of hydraulic fluid supplied to the work machine cylinder 6 increases. This further reduces the flow rate of hydraulic fluid supplied to the slewing motor 5, preventing the meter-in pressure of the slewing valve 27 from rising excessively. By preventing the meter-in pressure of the slewing valve 27 from rising excessively, the acceleration torque of the slewing motor 5 is prevented from rising excessively, which in turn prevents a decrease in the operating speed of the work machine 4, allowing the work machine to operate stably in a combined manner and preventing a decrease in work efficiency.

[0233] 1...Work machine, 2...Traction unit, 2A...Tracks, 3...Slewing unit, 4...Work machine, 4A...Boom, 4B...Arm, 4C...Bucket, 5...Slewing motor, 6...Work machine cylinder, 6A...Boom cylinder, 6B...Arm cylinder, 6C...Bucket cylinder, 7...Controller, 8...Operating device, 8A...Left work lever, 8B...Right work lever, 8C...Left travel lever, 8D...Right travel lever, 8E...Left foot pedal, 8F...Right foot pedal, 9...Monitor, 9A...Display device, 9B...Input device, 10...Cab, 11...Driver's seat, 12...Computer, 12A...Processor, 12B...Main unit Mori, 12C...Storage, 12D...Input / Output Interface, 12E...Communication Interface, 12F...Computer Program, 13...Control System, 14...Power Source, 15...Pump, 16...Tank, 17...Work Equipment Valve (Actuator Valve), 17A...Boom Valve, 17B...Arm Valve, 17C...Bucket Valve, 19...Pump Flow Channel, 20...Suction Flow Channel, 21...Bottom Flow Channel, 21A...Boom Bottom Flow Channel, 21B...Arm Bottom Flow Channel, 21C...Bucket Bottom Flow Channel, 22...Head Flow Channel, 22A...Boom Head Flow Channel, 22B...Arm Head Flow Channel, 22 C... Bucket head passage, 23... First motor passage, 24... Second motor passage, 27... Swivel valve, 31... Pump pressure sensor, 32... Swivel sensor, 33... Load pressure sensor, 33A... First load pressure sensor, 33B... Second load pressure sensor, 51... First port, 52... Second port, 61... Bottom chamber, 62... Head chamber, 71... Target swivel speed calculation unit, 72... Second swivel motor required flow rate calculation unit, 73... Swivel motor consumption flow rate calculation unit, 74... First swivel motor required flow rate calculation unit, 75... Selection unit, 76... Swivel valve control unit, 77... Pump control unit, 78... Memory unit, 79... Swivel motor target flow rate calculation unit, 80... Pump upper limit flow rate calculation unit, 81... Target operating speed calculation unit, 82... Work machine cylinder required flow rate calculation unit, 83... Work machine cylinder target flow rate calculation unit, 84... Work machine valve control unit, Ars... Target opening area, Es... Swivel operation amount, Ew... Work machine operation amount, Qa... Assist flow rate, Qc... Consumption flow rate, Qmp... Upper limit flow rate, Qp... Pump flow rate, Qra... First swivel motor required flow rate, Qrs... Second swivel motor required flow rate, Qrw... Work machine cylinder required flow rate, Qts... Swivel motor target flow rate, Qtw... Work machine cylinder target flow rate, R... Time change rate, Vrs... Target swivel speed, Vrw... Target operating speed.

Claims

1. A control system for a work machine comprising: a slewing body; a pump for discharging hydraulic fluid; a slewing motor supplied with hydraulic fluid from the pump to slewing the slewing body; a slewing sensor for detecting the slewing speed of the slewing body; and a controller, wherein the controller calculates a consumption flow rate indicating the flow rate of the hydraulic fluid passing through the slewing motor based on the detection data of the slewing sensor; calculates a first slewing motor request flow rate indicating the flow rate of the hydraulic fluid required by the slewing motor to maintain the accelerated state when the slewing speed of the slewing body is in an accelerated state, based on the consumption flow rate; and controls the pump flow rate indicating the flow rate of the hydraulic fluid discharged from the pump based on the first slewing motor request flow rate.

2. The control system for a work machine according to claim 1, wherein the controller calculates an assist flow rate indicating the flow rate of the hydraulic fluid to pressurize the hydraulic fluid in the swing motor based on the consumption flow rate, and calculates the first swing motor required flow rate by adding the assist flow rate to the consumption flow rate.

3. The control system for a work machine according to claim 2, wherein the assist flow rate decreases as the consumption flow rate increases.

4. The control system for a work machine according to claim 3, wherein the controller acquires a rotation operation amount for operating the rotation motor, calculates a target rotation speed indicating a target value for the rotation speed of the rotation body based on the rotation operation amount, and changes the assist flow rate based on the target rotation speed.

5. The control system for a work machine according to claim 2, wherein the controller acquires a rotation operation amount for operating the rotation motor, calculates a second rotation motor required flow rate indicating the flow rate of the hydraulic fluid required by the rotation motor when the rotation speed of the rotation body is in a steady state based on the rotation operation amount, and controls the pump flow rate based on the second rotation motor required flow rate if the second rotation motor required flow rate is less than the first rotation motor required flow rate.

6. The control system for a work machine according to claim 5, wherein the controller changes the rate of change of the pump flow rate over time based on the consumption flow rate.

7. The controller acquires a rotation operation amount for operating the rotation motor, calculates a second rotation motor required flow rate indicating the flow rate of the hydraulic fluid required by the rotation motor when the rotation speed of the rotation body is in a steady state, based on the rotation operation amount, and controls the pump flow rate based on the second rotation motor required flow rate if the rotation sensor is abnormal, the control system for a working machine according to claim 1.

8. A control system for a work machine according to claim 1, comprising a swivel valve for controlling the flow rate of hydraulic fluid supplied from the pump to the swivel motor, wherein the controller acquires a swivel operation amount for operating the swivel motor, calculates a second swivel motor required flow rate indicating the flow rate of the hydraulic fluid required by the swivel motor when the swivel speed of the swivel body is in a steady state based on the swivel operation amount, and controls the opening area of ​​the swivel valve based on the second swivel motor required flow rate.

9. The apparatus comprises: a slewing body; a work machine attached to the slewing body; a pump for discharging hydraulic fluid; a slewing motor supplied with hydraulic fluid from the pump to slewing the slewing body; a work machine cylinder supplied with hydraulic fluid from the pump to operate the work machine; a slewing valve for controlling the flow rate of hydraulic fluid supplied from the pump to the slewing motor; a work machine valve for controlling the flow rate of hydraulic fluid supplied from the pump to the work machine cylinder; and a controller, wherein the controller acquires a slewing operation amount for operating the slewing motor; acquires a work machine operation amount for operating the work machine cylinder; calculates a first slewing motor required flow rate indicating the flow rate of hydraulic fluid required by the slewing motor to maintain the accelerated state when the slewing speed of the slewing body is in an accelerated state; and calculates a second slewing motor required flow rate indicating the flow rate of hydraulic fluid required by the slewing motor when the slewing speed of the slewing body is in a steady state, based on the slewing operation amount. A control system for a work machine that calculates a work machine cylinder required flow rate, which indicates the flow rate of the hydraulic fluid required by the work machine cylinder when the operating speed of the work machine is in a steady state, based on the amount of work machine operation, and controls at least one of the following based on the first slewing motor required flow rate, the second slewing motor required flow rate, and the work machine cylinder required flow rate: the pump flow rate, which indicates the flow rate of the hydraulic fluid discharged from the pump, the opening area of ​​the slewing valve, and the opening area of ​​the work machine valve.

10. A control system for a working machine according to claim 9, comprising a pump pressure sensor for detecting the pressure of the hydraulic fluid discharged from the pump, the controller calculating an upper limit flow rate indicating an upper limit of the flow rate of the hydraulic fluid discharged from the pump based on the detection data from the pump pressure sensor and the hardware characteristics of the pump, calculating a target flow rate for the working machine cylinder based on the upper limit flow rate, the required flow rate for the working machine cylinder and the required flow rate for the first swing motor, and controlling the opening area of ​​the working machine valve based on the target flow rate for the working machine cylinder.

11. When the sum of the flow rate requested by the first swing motor and the flow rate requested by the work machine cylinder exceeds the upper limit flow rate, the opening area of ​​the work machine valve decreases as the flow rate requested by the first swing motor increases, the control system for a work machine according to claim 10.

12. The control system for a work machine according to claim 10, wherein the controller calculates a target flow rate for the slewing motor based on the upper limit flow rate, the required flow rate for the work machine cylinder, and the required flow rate for the second slewing motor, and controls the opening area of ​​the slewing valve based on the target flow rate for the slewing motor.

13. When the sum of the flow rate requested by the second swivel motor and the flow rate requested by the work machine cylinder exceeds the upper limit flow rate, the opening area of ​​the swivel valve becomes smaller as the flow rate requested by the work machine cylinder increases, the control system for a work machine according to claim 12.

14. A control system for a work machine according to claim 9, comprising a slewing sensor for detecting the slewing speed of the slewing body, wherein the controller calculates a consumption flow rate indicating the flow rate of the hydraulic fluid passing through the slewing motor based on the detection data of the slewing sensor, and calculates the first slewing motor's required flow rate based on the consumption flow rate.

15. A control system for a work machine according to claim 10, wherein the controller acquires input data from an input device, determines an adjustment gain based on the input data, adjusts the target flow rate of the work machine cylinder by multiplying it by the adjustment gain, and controls the opening area of ​​the work machine valve based on the adjusted target flow rate of the work machine cylinder.

16. A control system for a working machine according to claim 12, wherein the controller acquires input data from an input device, determines an adjustment gain based on the input data, adjusts the target flow rate of the swivel motor by multiplying the target flow rate of the swivel motor by the adjustment gain, and controls the opening area of ​​the swivel valve based on the adjusted target flow rate of the swivel motor.

17. A slewing body, a work machine attached to the slewing body, a pump for discharging hydraulic fluid, a slewing motor supplied with hydraulic fluid from the pump to slewing the slewing body, a work machine cylinder supplied with hydraulic fluid from the pump to operate the work machine, a load pressure sensor for detecting the pressure of the hydraulic fluid supplied from the pump to the slewing motor, a slewing valve for controlling the flow rate of the hydraulic fluid supplied from the pump to the slewing motor, a work machine valve for controlling the flow rate of the hydraulic fluid supplied from the pump to the work machine cylinder, and a controller, wherein the slewing operation amount for operating the slewing motor is acquired, the work machine operation amount for operating the work machine cylinder is acquired, a target opening area of ​​the slewing valve is set based on the slewing operation amount, a target opening area of ​​the work machine valve is set based on the work machine operation amount, and a target pressure is set indicating a target value of the pressure of the hydraulic fluid supplied to the slewing motor during a combined slewing operation in which the slewing motor and the work machine valve are operated simultaneously. A control system for a working machine, which corrects at least one of the target opening area of ​​the working machine valve and the target opening area of ​​the swivel valve based on the target pressure and the data detected by the load pressure sensor, controls the opening area of ​​the swivel valve based on the corrected target opening area of ​​the swivel valve, and controls the opening area of ​​the working machine valve based on the corrected target opening area of ​​the working machine valve.

18. The control system for a work machine according to claim 17, wherein the controller corrects the target opening area of ​​the swivel valve in the correction calculation to make the target opening area set based on the swivel operation amount smaller.

19. The control system for a work machine according to claim 17, wherein the controller, in the correction calculation of the target opening area of ​​the work machine valve, corrects the target opening area of ​​the work machine set based on the amount of work machine operation to be larger.

20. The control system for a work machine according to claim 17, wherein the controller does not correct the target opening area of ​​the work machine valve and the target opening area of ​​the swivel valve when the load pressure sensor is abnormal.

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