Work machine

Abstract

A controller of this work machine has a manual operation function for calculating a manual operation target speed on the basis of an operation signal of an operating device, and a support function for calculating a support target speed. The controller: calculates an arbitrated target speed of a hydraulic actuator by arbitrating a plurality of target speeds; calculates a correction value for the target speeds by means of feedback control based on the deviation between the arbitrated target speed and an actual speed; corrects the arbitrated target speed of the hydraulic actuator on the basis of the correction value; and controls the operation of the hydraulic actuator. When the support function is enabled, the controller executes at least one of processing for resetting the correction value and processing for limiting the correction value on the basis of a limit value corresponding to the enabled support function.

Description

Work machine

[0001] The present invention relates to a work machine.

[0002] A work machine such as a hydraulic excavator includes a vehicle body including a revolving body, and a work device attached to the revolving body. The work device includes a boom (driven member) rotatably connected to the revolving body, a boom cylinder (hydraulic actuator) for driving the boom, an arm (driven member) rotatably connected to the tip of the boom, an arm cylinder (hydraulic actuator) for driving the arm, a bucket (driven member) rotatably connected to the tip of the arm, and a bucket cylinder (hydraulic actuator) for driving the bucket.

[0003] It is not easy to operate the driven members of the work machine by their respective manual operation levers and efficiently and neatly excavate a predetermined area with the work device without contacting obstacles such as people and objects around. Therefore, an operator who operates the work machine needs a skilled operation technique.

[0004] Therefore, in order to facilitate such work, a work support function (machine control function) that controls the operation of the hydraulic actuator so that the tip of the bucket does not exceed a preset non-invasion area is known. Also, in order to prevent the work device from contacting obstacles such as people and objects around, a driving support function (area control function) that detects obstacles around the work machine and decelerates or stops the operation of the work machine is known. In addition, in order to compensate for the shortage of skilled operators, the automatic driving function and remote operation function of work machines are also rapidly being developed and popularized.

[0005] In a work machine having such a function, a technique has been proposed to correct the deviation between the actuator target speed and the actuator actual speed by feedback control based on the deviation between the actuator target speed and the actuator actual speed obtained from the detection result of the sensor, and improve the accuracy of the control of the hydraulic actuator (see Patent Document 1).

[0006] Japanese Unexamined Patent Application Publication No. 2020-033815

[0007] Feedback control typically involves calculating correction values ​​using control gains in the controller. Ideally, these control gains should be set to values ​​optimal for the responsiveness and accuracy of the controlled system. Conversely, if control gains unsuitable for the characteristics of the controlled system are set, the control system becomes unstable, making it prone to vibrations (hunting) of the controlled system. Here, the control gains are generally set considering the operating characteristics of the vehicle system, and are typically matched to the operating conditions where the vehicle system prioritizes control accuracy the most, or to the operating conditions that are most frequently used.

[0008] However, as mentioned above, work machines may have multiple functions implemented, such as work support functions and driving support functions. When operating the vehicle body based on operation commands calculated by each function, it is quite possible that operations different from the above operating conditions will be desired. When operations different from the above operating conditions are performed, the control gain may not be at an appropriate value for that operation, and vibration (hunting) may occur in the hydraulic actuator being controlled. If hunting occurs, the control performance of the hydraulic actuator will deteriorate, and there is a risk that the function may not be executed properly. In addition, in feedback control, if the correction value calculated by the controller is not reset at the appropriate timing, unintended corrections may be made to the desired operation command, which may reduce the accuracy of the control. In this case as well, the control performance of the hydraulic actuator may deteriorate, and there is a risk that the function may not be executed properly.

[0009] The present invention aims to provide a work machine capable of appropriately performing multiple functions without degrading the control performance of a hydraulic actuator.

[0010] A working machine according to one aspect of the present invention includes a hydraulic actuator for driving a member to be driven, a hydraulic pump for supplying pressurized oil to the hydraulic actuator, a flow control valve for controlling the flow rate of pressurized oil supplied from the hydraulic pump to the hydraulic actuator, an operating device for operating the member to be driven, a controller for controlling the flow control valve based on an operating signal from the operating device, and a speed sensor for detecting the actual speed of the hydraulic actuator. The controller has a manual operation function for calculating a manual operation target speed, which is the target speed of the hydraulic actuator, based on an operating signal from the operating device, and a support function for calculating a support target speed, which is a target speed different from the manual operation target speed. The controller calculates a post-arrangement target speed of the hydraulic actuator by arbitrating a plurality of target speeds, calculates a correction value for the target speed by feedback control based on the deviation between the post-arrangement target speed and the actual speed of the hydraulic actuator, calculates a command speed by correcting the post-arrangement target speed of the hydraulic actuator based on the correction value, and controls the flow control valve so that the hydraulic actuator operates at the command speed. When the support function is enabled, the controller performs at least one of the following: a process to reset the correction value, and a process to limit the correction value based on a limit value corresponding to the enabled support function.

[0011] According to the present invention, it is possible to provide a work machine that can appropriately perform multiple functions without degrading the control performance of the hydraulic actuator.

[0012] Figure 1 is a side view of a hydraulic excavator 901, shown as an example of a work machine according to an embodiment of the present invention. Figure 2 is a circuit diagram of a hydraulic drive system, showing hydraulic equipment connected to the first to third hydraulic pumps. Figure 3 is a circuit diagram of a hydraulic drive system, showing a solenoid valve connected to a pilot pump, a controller that controls the solenoid valve, etc., and equipment connected to the controller. Figure 4 is a functional block diagram of the controller 300. Figure 5 is a block diagram showing the details of the valve control unit 320. Figure 6 is a calculation block diagram of the target speed arbitration unit 314. Figure 7 is a calculation block diagram of the reset signal calculation unit 315. Figure 8 is a calculation block diagram of the unstable state determination unit 316. Figure 9 is a calculation block diagram of the limit value calculation unit 317. Figure 10 is a calculation block diagram of the command speed calculation unit 318. Figure 11 is a flowchart showing an example of processing performed by the controller 300. This is a calculation block diagram of the target speed arbitration unit 314 according to a modified example.

[0013] An embodiment of the present invention will be described with reference to Figures 1 to 11.

[0014] Figure 1 is a side view of a hydraulic excavator 901, which is shown as an example of a work machine according to an embodiment of the present invention. As shown in Figure 1, the hydraulic excavator 901 comprises a machine body 220 and a front work device (hereinafter referred to as work device) 203 attached to the machine body 220. The machine body 220 comprises a crawler-type traveling body 201 and a slewing body 202 that is rotatably mounted relative to the traveling body 201.

[0015] The vehicle body 201 is equipped with a pair of hydraulic motors for driving (hereinafter referred to as "driving motors"). The left crawler is driven by a driving motor (also referred to as the left driving motor) 201L, and the right crawler (not shown) is driven by a driving motor (also referred to as the right driving motor), so that the left and right crawlers are rotated independently. As a result, the vehicle body 201 moves forward or backward.

[0016] The slewing body 202 includes a slewing frame 202a, a driver's cab 207 provided on the front side of the slewing frame 202a, a counterweight 209 provided on the rear side of the slewing frame 202a, and a machine room 208 provided between the driver's cab 207 and the counterweight 209. The driver's cab 207 is equipped with an operating device (including the operating levers 115a and 115b in Figure 3) that outputs operating signals for operating the work device 203, the traveling body 201, and the slewing body 202, as well as a driver's seat where the operator sits, and a controller 300 that controls various parts of the hydraulic excavator 901. The operating device includes operating members such as operating levers and operating pedals operated by the operator, and an operating amount sensor that detects the amount of operation of the operating members. The operating amount sensor outputs a signal representing the detection result as an operating signal to the controller 300.

[0017] The machine room 208 houses the prime mover, the engine 217, a hydraulic pump driven by the engine 217, a hydraulic motor 211 for slewing (hereinafter referred to as the slewing motor), and a control valve unit 210 including multiple control valves that control the flow of hydraulic fluid supplied to the hydraulic actuator discharged from the hydraulic pump. The counterweight 209 is provided to ensure the weight balance of the hydraulic excavator 901. The slewing body 202 is slewing to the right or left relative to the traveling body 201 by the slewing motor 211.

[0018] The working device 203 is a multi-jointed working device attached to the slewing body 202, and has multiple hydraulic actuators (hydraulic cylinders) and multiple (three in this embodiment) driveable members (front members) driven by the multiple hydraulic actuators. The driveable members, the boom 204, arm 205, and bucket 206, are connected in series. The multiple hydraulic actuators (boom cylinder 204a, arm cylinder 205a, and bucket cylinder 206a) are operated by the discharge pressure of hydraulic pumps (first hydraulic pump 1, second hydraulic pump 2, and third hydraulic pump 3 shown in Figure 2) to drive the working device 203. Excavation and other operations are performed by driving the working device 203 with the multiple hydraulic actuators.

[0019] The boom 204 is rotatably connected at its base to the front of the slewing body 202 via a boom pin. The arm 205 is rotatably connected at its base to the tip of the boom 204 via an arm pin. The bucket 206 is rotatably connected to the tip of the arm 205 via a bucket pin.

[0020] The boom 204 is rotationally driven vertically by the extension and retraction of the boom cylinder 204a, which is a hydraulic cylinder. The arm 205 is rotationally driven vertically by the extension and retraction of the arm cylinder 205a, which is a hydraulic cylinder. The bucket 206 is rotationally driven vertically by the extension and retraction of the bucket cylinder 206a, which is a hydraulic cylinder. One end of the boom cylinder 204a is connected to the boom 204 and the other end is connected to the slewing frame 202a of the slewing body 202. One end of the arm cylinder 205a is connected to the arm 205 and the other end is connected to the boom 204. One end of the bucket cylinder 206a is connected to the bucket 206 via a bucket link and the other end is connected to the arm 205.

[0021] The hydraulic excavator 901 is equipped with multiple attitude sensors for detecting the attitude and operating state of the hydraulic excavator 901. The multiple attitude sensors include IMUs (Inertial Measurement Units) 212, 213, and 214 for detecting the attitude and operating state of the work device 203, and IMUs 215 and 216 for detecting the attitude of the machine body 220 and the rotational speed of the slewing body 202.

[0022] An IMU 212 is attached to the boom 204, an IMU 213 is attached to the arm 205, an IMU 214 is attached to the bucket link, and IMUs 215 and 216 are attached to the slewing body 202. IMUs 212 to 216 acquire the angular velocity and acceleration of the three orthogonal axes of the boom 204, arm 205, bucket 206, and slewing body 202, and output them to the controller 300. The controller 300 calculates the angle and angular velocity of the boom 204 around the boom pin, the angle and angular velocity of the arm 205 around the arm pin, the angle and angular velocity of the bucket 206 around the bucket pin, and attitude parameters such as the pitch angle, roll angle, slewing angle, and slewing speed of the slewing body 202. Alternatively, an IMU controller may be provided separately from the controller 300. The IMU controller may calculate attitude-related parameters based on signals from multiple IMUs 212 to 216 and output the calculation results to the controller 300.

[0023] As attitude sensors for the work device 203, potentiometers that output voltage signals corresponding to the rotation angles of the boom 204, arm 205, and bucket 206 may be used instead of the IMUs 212 to 214 mentioned above. Alternatively, stroke sensors that detect the stroke of the boom cylinder 204a, arm cylinder 205a, and bucket cylinder 206a may be used as attitude sensors for the work device 203. As attitude sensors for the machine body 220, tilt angle sensors or rotary encoders may be provided instead of the IMUs 215 and 216 mentioned above to detect the tilt angle (pitch angle and roll angle) of the machine body 220 and the slewing angle and slewing speed of the slewing body 202.

[0024] The hydraulic drive unit 902 of the hydraulic excavator 901 will be described with reference to Figures 2 and 3. Figures 2 and 3 are circuit diagrams of the hydraulic drive unit 902 according to the first embodiment of the present invention. Figure 2 shows the hydraulic equipment connected to the first to third hydraulic pumps 1 to 3, and Figure 3 shows the solenoid valve connected to the pilot pump, the controller 300 that controls the solenoid valve, etc., and the equipment connected to the controller 300.

[0025] As shown in Figures 2 and 3, the hydraulic drive unit 902 includes a first hydraulic pump 1, a second hydraulic pump 2, a third hydraulic pump 3, a pilot pump 111, a hydraulic oil tank 4, a plurality of control valves (directional control valves 6-16, flow control valves 21-29, bleed-off valves 34-36, and a merging valve 37), and a controller 300 that controls the operation of the plurality of control valves. The controller 300 controls the plurality of control valves shown in Figure 2 by controlling the solenoid valve shown in Figure 3. Hydraulic oil is stored in the hydraulic oil tank 4.

[0026] The first to third hydraulic pumps 1 to 3 shown in Figure 2 are driven by the engine 217 and draw hydraulic fluid from the hydraulic fluid tank 4 and discharge it to the discharge lines 41, 51, and 62. The first to third hydraulic pumps 1 to 3 are variable displacement hydraulic pumps whose discharge capacity (displacement volume per revolution) can be changed. The first to third hydraulic pumps 1 to 3 are, for example, swashplate type or oblique shaft type piston pumps. The pilot pump 111 shown in Figure 3 is driven by the engine 217 and draws hydraulic fluid from the hydraulic fluid tank 4 and discharges it to the pilot line 121. The pilot pump 111 is a fixed displacement hydraulic pump with a constant discharge capacity.

[0027] As shown in Figure 2, the discharge capacity (tilt angle) of the first hydraulic pump 1 is controlled by a regulator attached to the first hydraulic pump 1. The regulator of the first hydraulic pump 1 includes a command pressure chamber 1a. The discharge capacity (tilt angle) of the second hydraulic pump 2 is controlled by a regulator attached to the second hydraulic pump 2. The regulator of the second hydraulic pump 2 includes a command pressure chamber 2a. The discharge capacity (tilt angle) of the third hydraulic pump 3 is controlled by a regulator attached to the third hydraulic pump 3. The regulator of the third hydraulic pump 3 includes a command pressure chamber 3a.

[0028] The discharge line 41 of the first hydraulic pump 1 is connected to the hydraulic fluid tank 4 via the center bypass line 42. The center bypass line 42 has the following valves arranged in order from upstream to downstream: a right-travel directional control valve 6, a bucket directional control valve 7, a second arm directional control valve 8, and a first boom directional control valve 9. The right-travel directional control valve 6 is located between the first hydraulic pump 1 and the right-travel motor (not shown) and is a directional control valve that switches the flow direction of the pressurized oil supplied from the first hydraulic pump 1 to the right-travel motor (not shown). The bucket directional control valve 7 is located between the first hydraulic pump 1 and the bucket cylinder 206a and is a directional control valve that switches the flow direction of the pressurized oil supplied from the first hydraulic pump 1 to the bucket cylinder 206a. The second arm directional control valve 8 is located between the first hydraulic pump 1 and the arm cylinder 205a and is a directional control valve that switches the flow direction of the pressurized oil supplied from the first hydraulic pump 1 to the arm cylinder 205a. The first boom directional control valve 9 is installed between the first hydraulic pump 1 and the boom cylinder 204a and is a directional control valve that switches the flow direction of pressurized oil supplied from the first hydraulic pump 1 to the boom cylinder 204a.

[0029] Downstream of the right-travel directional control valve 6 on the center bypass line 42, the bucket directional control valve 7, the second arm directional control valve 8, and the first boom directional control valve 9 are connected in parallel by a parallel line 43 branching off from the center bypass line 42. The bucket directional control valve 7 is connected to the parallel line 43 via an oil passage 44. The second arm directional control valve 8 is connected to the parallel line 43 via an oil passage 46. The first boom directional control valve 9 is connected to the parallel line 43 via an oil passage 48.

[0030] The discharge line 41 is provided with a first main relief valve 31 that defines the maximum pressure of the discharge line 41 in order to protect the hydraulic circuit from excessive pressure rise. The first hydraulic pump 1 is connected to the hydraulic oil tank 4 via the first main relief valve 31 located in the oil passage 50 that branches off from the discharge line 41. A first bleed-off valve 34 is provided at the downstream end of the center bypass line 42. The first hydraulic pump 1 is connected to the hydraulic oil tank 4 via the first bleed-off valve 34.

[0031] The discharge line 51 of the second hydraulic pump 2 is connected to the hydraulic fluid tank 4 via the center bypass line 52. The center bypass line 52 has, in order from upstream to downstream, a second boom directional control valve 10, a first arm directional control valve 11, a first attachment directional control valve 12, and a left-travel directional control valve 13. The second boom directional control valve 10 is located between the second hydraulic pump 2 and the boom cylinder 204a and is a directional control valve that switches the flow direction of the pressurized oil supplied from the second hydraulic pump 2 to the boom cylinder 204a. The first arm directional control valve 11 is located between the second hydraulic pump 2 and the arm cylinder 205a and is a directional control valve that switches the flow direction of the pressurized oil supplied from the second hydraulic pump 2 to the arm cylinder 205a. The first attachment directional control valve 12 is provided between the second hydraulic pump 2 and the first actuator (not shown) that drives the first special attachment (not shown), and is a directional control valve that switches the flow direction of pressurized oil supplied from the second hydraulic pump 2 to the first actuator (not shown). The left travel directional control valve 13 is provided between the second hydraulic pump 2 and the left travel motor 201L, and is a directional control valve that switches the flow direction of pressurized oil supplied from the second hydraulic pump 2 to the left travel motor 201L.

[0032] The first special attachment is, for example, a small crushing machine that is installed in place of the bucket 206. The directional control valve 12 for the first attachment is used when the small crushing machine is mounted on the arm 205 in place of the bucket 206.

[0033] The second boom directional control valve 10, the first arm directional control valve 11, the first attachment directional control valve 12, and the left-travel directional control valve 13 are connected in parallel by a parallel line 53 that branches off from the center bypass line 52. The second boom directional control valve 10 is connected to the parallel line 53 via an oil passage 54. The first arm directional control valve 11 is connected to the parallel line 53 via an oil passage 56. The first attachment directional control valve 12 is connected to the parallel line 53 via an oil passage 58. The left-travel directional control valve 13 is connected to the parallel line 53 via an oil passage 60.

[0034] The discharge line 51 is provided with a second main relief valve 32 that defines the maximum pressure of the discharge line 51 in order to protect the hydraulic circuit from excessive pressure rise. The second hydraulic pump 2 is connected to the hydraulic oil tank 4 via the second main relief valve 32, which is located in the oil passage 61 connected to the parallel line 53. A second bleed-off valve 35 is provided at the downstream end of the center bypass line 52. The second hydraulic pump 2 is connected to the hydraulic oil tank 4 via the second bleed-off valve 35.

[0035] An oil passage 69 connected to the discharge line 41 of the first hydraulic pump 1 and a parallel line 53 connected to the discharge line 51 of the second hydraulic pump 2 are connected via a merging valve 37. Downstream of the merging valve 37, a left-travel direction control valve 13 is connected via an oil passage 60. A check valve (non-return valve) 38 is provided between the oil passage 60 and the merging valve 37 to prevent hydraulic fluid from flowing from the oil passage 60 to the merging valve 37. A check valve (non-return valve) 39 is provided between the oil passage 60 and the oil passage 58 to prevent hydraulic fluid from flowing from the oil passage 60 to the oil passage 58.

[0036] The discharge line 62 of the third hydraulic pump 3 is connected to the hydraulic fluid tank 4 via a center bypass line 63. The center bypass line 63 has, in order from upstream to downstream, a slewing directional control valve 14, a third boom directional control valve 15, and a second attachment directional control valve 16. The slewing directional control valve 14 is located between the third hydraulic pump 3 and the slewing motor 211 and is a directional control valve that switches the flow direction of pressurized oil supplied from the third hydraulic pump 3 to the slewing motor 211. The third boom directional control valve 15 is located between the third hydraulic pump 3 and the boom cylinder 204a and is a directional control valve that switches the flow direction of pressurized oil supplied from the third hydraulic pump 3 to the boom cylinder 204a. The second attachment directional control valve 16 is located between the third hydraulic pump 3 and the second actuator (not shown) that drives the second special attachment (not shown) and is a directional control valve that switches the flow direction of pressurized oil supplied from the third hydraulic pump 3 to the second actuator (not shown).

[0037] The directional control valve 16 for the second attachment is used when a second special attachment, which includes a second actuator in addition to the first special attachment, is mounted on the work device 203, or when a second special attachment, which includes two actuators, a first actuator and a second actuator, is mounted in place of the first special actuator.

[0038] The slewing directional control valve 14, the third boom directional control valve 15, and the second attachment directional control valve 16 are connected in parallel by a parallel line 64 that branches off from the center bypass line 63. The slewing directional control valve 14 is connected to the parallel line 64 via an oil passage 65. The third boom directional control valve 15 is connected to the parallel line 64 via an oil passage 67. The second attachment directional control valve 16 is connected to the parallel line 64 via an oil passage 69.

[0039] The discharge line 62 is equipped with a third main relief valve 33 that defines the maximum pressure of the discharge line 62 in order to protect the hydraulic circuit from excessive pressure rise. The third hydraulic pump 3 is connected to the hydraulic oil tank 4 via the third main relief valve 33, which is located in the oil passage 71 connected to the parallel line 64. A third bleed-off valve 36 is provided at the downstream end of the center bypass line 63. The third hydraulic pump 3 is connected to the hydraulic oil tank 4 via the third bleed-off valve 36.

[0040] Upstream of the bucket directional control valve 7, in the oil passage 44, there is a flow control valve (hereinafter also referred to as the bucket flow control valve) 21 that adjusts the flow rate of pressurized oil supplied from the first hydraulic pump 1 to the bucket cylinder 206a during combined operation. Upstream of the second arm directional control valve 8, in the oil passage 46, there is a flow control valve (hereinafter also referred to as the second arm flow control valve) 22 that adjusts the flow rate of pressurized oil supplied from the first hydraulic pump 1 to the arm cylinder 205a during combined operation. Upstream of the first boom directional control valve 9, in the oil passage 48, there is a flow control valve (hereinafter also referred to as the first boom flow control valve) 23 that adjusts the flow rate of pressurized oil supplied from the first hydraulic pump 1 to the boom cylinder 204a during combined operation.

[0041] Upstream of the second boom directional control valve 10, an oil passage 54 is provided with a flow control valve (hereinafter also referred to as the second boom flow control valve) 24 that adjusts the flow rate of pressurized oil supplied from the second hydraulic pump 2 to the boom cylinder 204a during combined operation. Upstream of the first arm directional control valve 11, an oil passage 56 is provided with a flow control valve (hereinafter also referred to as the first arm flow control valve) 25 that adjusts the flow rate of pressurized oil supplied from the second hydraulic pump 2 to the arm cylinder 205a during combined operation. Upstream of the first attachment directional control valve 12, an oil passage 58 is provided with a flow control valve (hereinafter also referred to as the first attachment flow control valve) 26 that adjusts the flow rate of pressurized oil supplied from the second hydraulic pump 2 to the first attachment during combined operation.

[0042] In the oil passage 65 upstream of the swing direction control valve 14, a flow control valve (hereinafter also referred to as the swing flow control valve) 27 for adjusting the flow rate of the pressure oil supplied from the third hydraulic pump 3 to the swing motor 211 during combined operation is provided. In the oil passage 67 upstream of the boom 3 direction control valve 15, a flow control valve (hereinafter also referred to as the boom 3 flow control valve) 28 for adjusting the flow rate of the pressure oil supplied from the third hydraulic pump 3 to the boom cylinder 204a during combined operation is provided. In the oil passage 69 upstream of the second attachment direction control valve 16, a flow control valve (hereinafter also referred to as the second attachment flow control valve) 29 for adjusting the flow rate of the pressure oil supplied from the third hydraulic pump 3 to the second attachment during combined operation is provided.

[0043] As described above, the hydraulic drive device 902 includes a plurality of direction control valves 6 to 16 that control the flow direction of the pressure oil supplied to a plurality of hydraulic actuators (hydraulic cylinders and hydraulic motors), and a plurality of flow control valves 21 to 29 that are provided upstream of each of the plurality of direction control valves 6 to 16 and control the flow rate (i.e., the meter-in flow rate) of the pressure oil supplied to the plurality of hydraulic actuators.

[0044] The plurality of flow control valves 21 to 29 have the same configuration. For this reason, in FIG. 2, the configuration of the flow control valve 25 is shown as a representative, and the diagrams showing the configurations of the other flow control valves 21 to 24, 26 to 29 are omitted. The flow control valve 25 has a sheet-shaped poppet valve 45 and a pilot spool valve 47 that controls the opening area of the poppet valve 45. The pilot spool valve 47 operates according to the command pressure output from the solenoid valve unit 113 (see FIG. 3).

[0045] As shown in Fig. 3, the pilot pump 111 is connected to the hydraulic oil tank 4 via a pilot relief valve 112 for generating a pilot primary pressure. The pilot pump 111 is also connected to a solenoid valve unit 113 via a pilot line 121. The solenoid valve unit 113 includes a plurality of solenoid valves that output a command pressure to the regulators of the hydraulic pumps 1 to 3, the direction control valves 6 to 16, the flow control valves 21 to 29, the bleed-off valves 34 to 36, and the confluence valve 37. The plurality of solenoid valves are electromagnetic proportional pressure reducing valves that output, as a command pressure, a secondary pressure generated by reducing the primary pressure of the pilot pump 111 according to a control signal from the controller 300.

[0046] In Fig. 3, among the plurality of solenoid valves, a solenoid valve 113a that outputs a command pressure to the command pressure chamber 2a of the regulator of the second hydraulic pump 2, a solenoid valve 113b that outputs a command pressure to the command pressure chamber 11a of the direction control valve 11 for the first arm, a solenoid valve 113c that outputs a command pressure to the command pressure chamber 11b of the direction control valve 11 for the first arm, a solenoid valve 113d that outputs a command pressure to the command pressure chamber 25a of the flow control valve 25 for the first arm, and a solenoid valve 113e that outputs a command pressure to the command pressure chamber 35a of the second bleed-off valve 35 are shown, and the illustration of the other solenoid valves is omitted.

[0047] The solenoid valve 113a is connected to the command pressure chamber 2a via a pilot line 123 branched from the pilot line 121. The solenoid valve 113b is connected to the command pressure chamber 11a via a pilot line 124 branched from the pilot line 121. The solenoid valve 113c is connected to the command pressure chamber 11b via a pilot line 125 branched from the pilot line 121. The solenoid valve 113d is connected to the command pressure chamber 25a via a pilot line 126 branched from the pilot line 121. The solenoid valve 113e is connected to the command pressure chamber 35a via a pilot line 127 branched from the pilot line 121.

[0048] Multiple solenoid valves, which are not shown in the diagram, include solenoid valves that output command pressure to the command pressure chambers 1a and 3a of the regulators of hydraulic pumps 1 and 3, solenoid valves that output command pressure to the command pressure chambers of directional control valves 6 to 10 and 12 to 16, solenoid valves that output command pressure to the command pressure chambers of flow control valves 21 to 24 and 26 to 29, solenoid valves that output command pressure to the command pressure chambers 34a and 36a of bleed-off valves 34 and 36, and solenoid valves that output command pressure to the command chamber 37a of the merging valve 37.

[0049] The hydraulic drive unit 902 includes an operating lever 115a that can switch the first boom directional control valve 9, the second boom directional control valve 10, and the third boom directional control valve 15, and an operating lever 115b that can switch the first arm directional control valve 11 and the second arm directional control valve 8. For the sake of simplicity, the right travel operating lever for switching the right travel directional control valve 6, the bucket operating lever for switching the bucket directional control valve 7, the first attachment operating lever for switching the first attachment directional control valve 12, the left travel operating lever for switching the left travel directional control valve 13, the slewing operating lever for switching the slewing directional control valve 14, and the second attachment operating lever for switching the second attachment directional control valve 16 are not shown in the illustration.

[0050] As shown in Figure 2, a pressure sensor (also referred to as a pump pressure sensor) 84 is provided in the discharge line 41 of the first hydraulic pump 1 to detect the pump pressure, which is the discharge pressure of the first hydraulic pump 1. A pressure sensor (also referred to as a pump pressure sensor) 85 is provided in the discharge line 51 of the second hydraulic pump 2 to detect the pump pressure, which is the discharge pressure of the second hydraulic pump 2. A pressure sensor (also referred to as a pump pressure sensor) 86 is provided in the discharge line 62 of the third hydraulic pump 3 to detect the pump pressure, which is the discharge pressure of the third hydraulic pump 3.

[0051] An actuator line 72a connected to the bottom chamber of the boom cylinder 204a is provided with a pressure sensor (also referred to as an actuator pressure sensor or boom bottom pressure sensor) 87a for detecting the pressure in the bottom chamber of the boom cylinder 204a (also referred to as actuator pressure or boom bottom chamber pressure). An actuator line 72b connected to the rod chamber of the boom cylinder 204a is provided with a pressure sensor (also referred to as an actuator pressure sensor or boom rod pressure sensor) 87b for detecting the pressure in the rod chamber of the boom cylinder 204a (also referred to as actuator pressure or boom rod chamber pressure).

[0052] An actuator line 73a connected to the bottom chamber of the arm cylinder 205a is provided with a pressure sensor (also referred to as actuator pressure sensor or arm bottom pressure sensor) 88a for detecting the pressure in the bottom chamber of the arm cylinder 205a (also referred to as actuator pressure or arm bottom chamber pressure). An actuator line 73b connected to the rod chamber of the arm cylinder 205a is provided with a pressure sensor (also referred to as actuator pressure sensor or arm rod pressure sensor) 88b for detecting the pressure in the rod chamber of the arm cylinder 205a (also referred to as actuator pressure or arm rod chamber pressure).

[0053] An actuator line 74a connected to the bottom chamber of the bucket cylinder 206a is provided with a pressure sensor (also referred to as an actuator pressure sensor or bucket bottom pressure sensor) 89a for detecting the pressure in the bottom chamber of the bucket cylinder 206a (also referred to as actuator pressure or bucket bottom chamber pressure). An actuator line 74b connected to the rod chamber of the bucket cylinder 206a is provided with a pressure sensor (also referred to as an actuator pressure sensor or bucket rod pressure sensor) 89b for detecting the pressure in the rod chamber of the bucket cylinder 206a (also referred to as actuator pressure or bucket rod chamber pressure).

[0054] An actuator line 75a connected to the left-turn inlet port of the swing motor 211 is provided with a pressure sensor (also referred to as an actuator pressure sensor or left-turn inlet pressure sensor) 90a that detects the pressure on the left-turn inlet side of the swing motor 211 (also referred to as actuator pressure or left-turn inlet pressure). An actuator line 75b connected to the right-turn inlet port of the swing motor 211 is provided with a pressure sensor (also referred to as an actuator pressure sensor or right-turn inlet pressure sensor) 90b that detects the pressure on the right-turn inlet side of the swing motor 211 (also referred to as actuator pressure or right-turn inlet pressure).

[0055] Each pressure sensor (84-90b) outputs a detection signal to the controller 300, which is a signal representing the detected pressure. Note that, to avoid complicating the explanation, the pressure sensors for detecting the actuator pressure of the left travel motor (not shown), the right travel motor (not shown), and the attachments (not shown) are omitted from the illustration.

[0056] Pilot line 123 is provided with a pressure sensor 133 that detects the flow control command pressure of the second hydraulic pump 2 controlled by the solenoid valve 113a (i.e., the oil pressure in the command pressure chamber 2a). Pilot lines 124 and 125 are provided with pressure sensors 134 and 135 that detect the command pressure of the first arm directional control valve 11 controlled by the solenoid valves 113b and 113c (i.e., the oil pressure in the command pressure chamber 11a and the oil pressure in the command pressure chamber 11b). Pilot line 126 is provided with a pressure sensor 136 that detects the command pressure of the first arm flow control valve 25 controlled by the solenoid valve 113d (i.e., the oil pressure in the command pressure chamber 25a). Pilot line 127 is provided with a pressure sensor 137 that detects the command pressure of the bleed-off valve 35 controlled by the solenoid valve 113e (i.e., the oil pressure in the command pressure chamber 35a).

[0057] Each pressure sensor (133-137) outputs a detection signal to the controller 300, which is a signal representing the detected pressure. For the sake of brevity, the illustration omits the pressure sensors that detect the command pressure of the solenoid valves controlling the first hydraulic pump 1, third hydraulic pump 3, right travel directional control valve 6, bucket directional control valve 7, second arm directional control valve 8, first boom directional control valve 9, second boom directional control valve 10, first attachment directional control valve 12, left travel directional control valve 13, slewing directional control valve 14, third boom directional control valve 15, second attachment directional control valve 16, bucket flow control valve 21, second arm flow control valve 22, first boom flow control valve 23, second boom flow control valve 24, first attachment flow control valve 26, slewing flow control valve 27, third boom flow control valve 28, second attachment flow control valve 29, bleed-off valve 34, bleed-off valve 36, and merging valve 37.

[0058] The electrical signal lines connecting the controller 300 and each solenoid valve of the solenoid valve unit 113 are equipped with current sensors that detect the control current output from the controller 300 to each solenoid valve of the solenoid valve unit 113 and output a signal representing the detection result to the controller 300. Current sensor 143 detects the control current output from the controller 300 to solenoid valve 113a. Current sensor 144 detects the control current output from the controller 300 to solenoid valve 113b. Current sensor 145 detects the control current output from the controller 300 to solenoid valve 113c. Current sensor 146 detects the control current output from the controller 300 to solenoid valve 113d. Current sensor 147 detects the control current output from the controller 300 to solenoid valve 113e.

[0059] For the sake of brevity, the current sensors that detect the control current output to the solenoid valves controlling the first hydraulic pump 1, third hydraulic pump 3, right travel directional control valve 6, bucket directional control valve 7, second arm directional control valve 8, first boom directional control valve 9, second boom directional control valve 10, first attachment directional control valve 12, left travel directional control valve 13, slewing directional control valve 14, third boom directional control valve 15, second attachment directional control valve 16, bucket flow control valve 21, second arm flow control valve 22, first boom flow control valve 23, second boom flow control valve 24, first attachment flow control valve 26, slewing flow control valve 27, third boom flow control valve 28, second attachment flow control valve 29, bleed-off valve 34, bleed-off valve 36, and merging valve 37 are not shown in the diagram.

[0060] As shown in Figure 2, the hydraulic oil tank 4 is equipped with a temperature sensor 91 for detecting the temperature of the hydraulic oil inside the tank 4. As shown in Figure 3, the pilot line 121 is equipped with a temperature sensor 92 for detecting the temperature of the hydraulic oil flowing through the pilot line 121. The temperature sensors 91 and 92 output signals representing the detected temperatures to the controller 300.

[0061] As shown in Figure 3, the controller 300 receives signals output from the operating device 150, pump pressure detection device 151, actuator pressure detection device 152, temperature detection device 153, pilot pressure detection device 154, current detection device 155, and attitude detection device 156. The operating device 150 has a plurality of operating levers (for example, operating levers 115a, 115b) for operating each of the hydraulic actuators described above. The pump pressure detection device 151 has a pump pressure sensor 84 for the first hydraulic pump 1, a pump pressure sensor 85 for the second hydraulic pump 2, and a pump pressure sensor 86 for the third hydraulic pump 3. The actuator pressure detection device 152 has a plurality of actuator pressure sensors (for example, boom bottom pressure sensor 87a, boom rod pressure sensor 87b, arm bottom pressure sensor 88a, arm rod pressure sensor 88b, bucket bottom pressure sensor 89a, bucket rod pressure sensor 89b, left turn inlet pressure sensor 90a, and right turn inlet pressure sensor 90b). The temperature detection device 153 has the temperature sensors 91 and 92 described above. The pilot pressure detection device 154 includes a plurality of pressure sensors (e.g., pressure sensors 133 to 137) for detecting the pressure of the pilot line described above. The current detection device 155 has a plurality of current sensors (e.g., current sensors 143 to 147) described above. The attitude detection device 156 has the IMUs 212 to 216, which are attitude sensors described above.

[0062] The controller 300 receives signals from the control amount sensor of the operating device 150 described above, pressure sensors 84-90b, 133-137 (including pressure sensors not shown), current sensors 143-147 (including current sensors not shown), temperature sensors 91, 92, and IMUs 212-216. The controller 300 outputs control signals to each of the solenoid valves 113a-113e (including solenoid valves not shown) of the solenoid valve unit 113. In other words, the controller 300 controls the solenoid valves 113a-113e (including solenoid valves not shown) based on detection signals from the various sensors.

[0063] The controller 300 consists of a computer equipped with processing units 300v such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), and DSP (Digital Signal Processor), non-volatile memory 300w such as ROM (Read Only Memory), flash memory, and hard disk drive, volatile memory 300x known as RAM (Random Access Memory), an input interface 300y, an output interface 300z, and other peripheral circuits. The controller 300 may be composed of one computer or multiple computers. Furthermore, the processing unit 300v can be an ASIC (application specific integrated circuit), an FPGA (Field Programmable Gate Array), or the like.

[0064] The non-volatile memory 300w stores programs, thresholds, data tables, etc., that can perform various calculations. In other words, the non-volatile memory 300w is a storage medium (memory device) that can read programs that realize the functions of this embodiment. The processing unit 300v is an arithmetic unit that expands the program stored in the non-volatile memory 300w into the volatile memory 300x and performs calculations, and performs predetermined calculation processing on signals taken in from the input interface 300y, the non-volatile memory 300w, and the volatile memory 300x according to the program.

[0065] The input interface 300y converts signals input from various sensors into a format that can be processed by the processing unit 300v. The output interface 300z generates an output signal according to the calculation result of the processing unit 300v and outputs that signal to various devices (solenoid valves 113a to 113e, etc.).

[0066] The hydraulic excavator 901 according to this embodiment is equipped with a manual operation function and a plurality of support functions. The plurality of support functions include a machine control function, which is one of the work support functions, and an area control function, which is one of the driving support functions. The manual operation function is a function that operates the hydraulic actuator at a speed corresponding to the operation of the operating device 150 by the operator.

[0067] The machine control function controls various parts of the hydraulic excavator 901 so that no part of the excavator 901 (for example, the bucket 206) deviates from the pre-set working range, such as height, depth, and slewing angle.

[0068] The area control function detects obstacles around the hydraulic excavator 901 and notifies the operator, as well as slowing down or stopping various parts of the hydraulic excavator 901. This prevents the hydraulic excavator 901 from coming into contact with obstacles such as surrounding workers, pedestrians, or objects.

[0069] Various functions are set by a support function setting device 116 located in the driver's cab 207. The support function setting device 116 is an input device that can be operated by the operator and includes, for example, an MC enable switch for selecting whether to enable or disable the machine control function, and an AC enable switch for selecting whether to enable or disable the area control function. The controller 300 enables or disables various functions according to the function activation flags Fa (Fa2, Fa3), which are signals from the switches of the support function setting device 116. When the support function is enabled, if predetermined conditions are met during manual operation, the controller 300 intervenes and the hydraulic actuator is controlled semi-automatically or automatically. For this reason, the manual operation function can be said to be always enabled.

[0070] When the MC activation switch of the support function setting device 116 is turned ON, the support function setting device 116 outputs the function activation flag Fa2 = "1", and the controller 300 activates the machine control function. When the MC activation switch of the support function setting device 116 is turned OFF, the support function setting device 116 outputs the function activation flag Fa2 = "0", and the controller 300 disables the machine control function. When the AC activation switch of the support function setting device 116 is turned ON, the support function setting device 116 outputs the function activation flag Fa3 = "1", and the controller 300 activates the area control function. When the AC activation switch of the support function setting device 116 is turned OFF, the support function setting device 116 outputs the function activation flag Fa3 = "0", and the controller 300 disables the area control function.

[0071] As described above, when the MC activation switch of the support function setting device 116 is operated from the off position to the on position, the machine control function transitions from an disabled state to an enabled state. This switches the priority function from the manual operation function to the support function (machine control function). When the AC activation switch of the support function setting device 116 is operated from the off position to the on position, the area control function transitions from an disabled state to an enabled state. This switches the priority function from the manual operation function to the support function (area control function).

[0072] The functions of the controller 300 will be explained in detail with reference to Figures 4 to 10. Figure 4 is a functional block diagram of the controller 300. Figure 5 is a block diagram detailing the valve control unit 320 shown in Figure 4. As shown in Figure 4, the controller 300 functions as a manual operation control unit 311, a machine control unit 312, an area control unit 313, a target speed arbitration unit 314, a reset signal calculation unit 315, an unstable state determination unit 316, a limit value calculation unit 317, a command speed calculation unit 318, an actual speed calculation unit 319, and a valve control unit 320 by executing a program stored in the non-volatile memory 300w.

[0073] The manual operation control unit 311 calculates the manual operation target speed Vt1 according to the operation signal input from the operation device 150. The larger the amount of operation of the operation device 150, the larger the manual operation target speed Vt1 of the hydraulic actuator becomes.

[0074] The machine control unit 312 calculates a machine control target speed Vt2 for operating the hydraulic actuator so that the hydraulic excavator 901 does not deviate from the working range, such as height, depth, and slewing angle, which are set in advance.

[0075] The machine control unit 312 controls the operation of each hydraulic actuator based on the position and orientation of the hydraulic excavator 901, the posture of each part of the hydraulic excavator 901, and position information defining the working range. The position and orientation of the hydraulic excavator 901 are detected by a position detection device (not shown), such as a GNSS (Global Navigation Satellite System) antenna. The posture of each part of the hydraulic excavator 901 is detected by a posture detection device 156.

[0076] The machine control unit 312 calculates a machine control target speed Vt2 such that the hydraulic actuator decelerates as the distance to the boundary of the working range decreases. In other words, semi-automatic control is performed in which the machine control intervenes in the operator's operation. The boundary of the working range is, for example, a horizontal plane set above the hydraulic excavator 901 to avoid contact with power lines, etc. The boundary of the working range is, for example, a vertical plane set to the side of the hydraulic excavator 901 to avoid contact with utility poles, etc.

[0077] Furthermore, the machine control unit 312 calculates an actuator target speed Vt2 for automatically controlling the boom 204, which is not being operated by the operator, when the operator moves the bucket 206 along a predetermined target excavation surface (work surface) by operating the arm cloud. The machine control unit 312 also calculates an actuator target speed Vt2 for semi-automatic control of the arm 205. In other words, automatic control of the hydraulic actuator (boom cylinder 204a) that is not being operated by the operator and semi-automatic control of the hydraulic actuator (arm cylinder 205a) that is being operated by the operator are performed.

[0078] The area control unit 313 calculates an area control target speed Vt3 to decelerate or stop various parts of the hydraulic excavator 901 (for example, the work device 203 and the slewing body 202) in order to prevent the hydraulic excavator 901 from coming into contact with obstacles such as surrounding workers, pedestrians, and objects. Obstacles are detected by obstacle detection sensors (not shown), such as LiDAR (Light Detection and Ranging) and stereo cameras. The area control unit 313 calculates the relative position of the obstacle with respect to the hydraulic excavator 901 based on the detection results of the obstacle detection sensors. The area control unit 313 calculates the area control target speed Vt3 so that the hydraulic actuator decelerates as the distance to the obstacle decreases. In other words, semi-automatic control is performed in which area control intervenes in the operator's operation.

[0079] The machine control unit 312 and the area control unit 313 determine whether a reset condition has been met when control by the support function is being performed. For example, when the machine control unit 312 moves the bucket 206 along the target excavation surface (e.g., the horizontal plane) in response to the operator's arm cloud operation, it switches the operating direction of the boom 204 from an upward movement to a downward movement. The reset condition is met when the operating direction of the boom cylinder 204a changes from an extension direction to a contraction direction. When the reset condition is met, the machine control unit 312 outputs an MC reset signal. The reset condition may also be a change in the operating direction of the hydraulic actuator, or it may be that the speed command for operating the hydraulic actuator becomes 0.

[0080] The target speed arbitration unit 314 calculates the arbitrated target speed Vt and the adopted function number N based on the manual operation target speed Vt1 calculated by the manual operation control unit 311, the machine control target speed Vt2 calculated by the machine control unit 312, the area control target speed Vt3 calculated by the area control unit 313, and the function activation flag Fa, which is a signal input from the support function setting device 116.

[0081] Referring to Figure 6, the processing details of the target speed arbitration unit 314 will be explained in detail. Figure 6 is a calculation block diagram of the target speed arbitration unit 314. The manual operation target speed Vt1, machine control target speed Vt2, and area control target speed Vt3 have a priority order such that priority increases in this order. In other words, the priority is set in advance so that the area control target speed Vt3 has the highest priority from a safety standpoint, followed by the machine control target speed Vt2 from a control accuracy standpoint. The target speed arbitration unit 314 calculates the arbitrated target speed Vt by arbitrating the multiple target speeds Vt1 to Vt3 based on the function activation flag Fa and the predetermined priority order.

[0082] Arrangement refers to the calculation of processing multiple signals to obtain the output of a single signal. For example, as shown in Figure 6, the target speed arbitration unit 314 calculates one target speed as the arbitrated target speed Vt, taking into account the priority order of the multiple target speeds Vt1 to Vt3 that have been calculated. As shown in Figure 6, the target speed arbitration unit 314 includes a first speed selection unit 314a, a second speed selection unit 314b, a first number selection unit 314c, and a second number selection unit 314d.

[0083] If the function activation flag Fa2 of the machine control function is set to "1" by the support function setting device 116, the first speed selection unit 314a selects the machine control target speed Vt2 from the manual operation target speed Vt1. On the other hand, if the function activation flag Fa2 of the machine control function is set to "0" by the support function setting device 116, the first speed selection unit 314a selects the manual operation target speed Vt1 from the manual operation target speed Vt1 and the machine control target speed Vt2.

[0084] If the function activation flag Fa3 of the area control function is set to "1" by the support function setting device 116, the second speed selection unit 314b selects the area control target speed Vt3 as the mediated target speed Vt from the target speed and area control target speed Vt3 selected by the first speed selection unit 314a. On the other hand, if the function activation flag Fa3 of the area control function is set to "0" by the support function setting device 116, the second speed selection unit 314b selects the target speed selected by the first speed selection unit 314a as the mediated target speed Vt from the target speed and area control target speed Vt3 selected by the first speed selection unit 314a.

[0085] The first number selection unit 314c selects adopted function number "2" from adopted function number "1" and adopted function number "2" when the function activation flag Fa2 of the machine control function is set to "1" by the support function setting device 116. On the other hand, the first number selection unit 314c selects adopted function number "1" from adopted function number "1" and adopted function number "2" when the function activation flag Fa2 of the machine control function is set to "0" by the support function setting device 116.

[0086] If the function activation flag Fa3 of the area control function is set to "1" by the support function setting device 116, the second number selection unit 314d selects the adopted function number "3" as the adopted function number N from among the adopted function number and adopted function number "3" selected by the first number selection unit 314c. On the other hand, if the function activation flag Fa3 of the area control function is set to "0" by the support function setting device 116, the second number selection unit 314d selects the adopted function number selected by the first number selection unit 314c as the adopted function number N from among the adopted function number and adopted function number "3" selected by the first number selection unit 314c.

[0087] In this way, the target speed arbitration unit 314 calculates the arbitrated target speed Vt and, based on the function activation flags Fa2 and Fa3, calculates the adopted function number N from among the function numbers assigned to the manual operation function, machine control function, and area control function, respectively, which is the function adopted for the arbitrated target speed Vt. In other words, the target speed arbitration unit 314 determines the highest priority function, which is the function that should be given the most priority among the multiple functions (manual operation function, machine control function, and area control function), based on the priority order.

[0088] For example, when the machine control function is enabled and the area control function is disabled, the machine control function is determined as the highest priority function. In this case, the adopted function number N will be the function number "2" assigned to the machine control function. When both the machine control function and the area control function are enabled, the area control function is determined as the highest priority function. In this case, the adopted function number N will be the function number "3" assigned to the area control function. When both the machine control function and the area control function are disabled, the manual operation function is determined as the highest priority function. In this case, the adopted function number N will be the function number "1" assigned to the manual operation function.

[0089] As shown in Figure 4, the reset signal calculation unit 315 calculates the post-arrangement reset signal R based on the manual operation target speed Vt1 calculated by the manual operation control unit 311, the adopted function number N calculated by the target speed arbitration unit 314, the MC reset signal R2 output from the machine control unit 312, and the AC reset signal R3 output from the area control unit 313.

[0090] Referring to Figure 7, the processing contents of the reset signal calculation unit 315 will be explained in detail. Figure 7 is a block diagram of the reset signal calculation unit 315. As shown in Figure 7, the reset signal calculation unit 315 includes a manual operation reset signal calculation unit 315a, a function switching determination unit 315b, a first reset signal selection unit 315c, and a second reset signal selection unit 315d.

[0091] The manual operation reset signal calculation unit 315a determines whether the manual operation target speed Vt1 is 0 or not. If the manual operation target speed Vt1 is not 0, the manual operation reset signal calculation unit 315a does not output the manual operation reset signal R1. If the manual operation target speed Vt1 is 0, the manual operation reset signal calculation unit 315a outputs the manual operation reset signal R1.

[0092] The function switching determination unit 315b receives input such as the adopted function number N and the manual operation target speed Vt1 repeatedly at a predetermined calculation cycle. The function switching determination unit 315b determines whether the adopted function number N (previous value) calculated in the previous calculation cycle is the same as the adopted function number N (current value) calculated in the current calculation cycle. If the previous value and the current value of the adopted function number N are the same, it outputs a signal S indicating that the preferred function has been switched.

[0093] The first reset signal selection unit 315c selects the manual operation reset signal R1 when the adopted function number N is set to "1" by the target speed arbitration unit 314. The first reset signal selection unit 315c selects the MC reset signal R2 when the adopted function number N is set to "2" by the target speed arbitration unit 314. The first reset signal selection unit 315c selects the AC reset signal R3 when the adopted function number N is set to "3" by the target speed arbitration unit 314.

[0094] The second reset signal selection unit 315d outputs the input reset signal as a mediated reset signal R when the reset signal selected by the first reset signal selection unit 315c is input. Furthermore, when the second reset signal selection unit 315d receives a signal S indicating that the adopted function number N has been switched (that the preferred function has been switched), it outputs the reset signal corresponding to the current value of the adopted function number N as a mediated reset signal R.

[0095] Therefore, for example, when the adopted function number N is set to "1", and the manual operation target speed Vt1 changes from a predetermined value greater than 0 to 0, the manual operation reset signal R1 is output from the reset signal calculation unit 315 as a post-arrangement reset signal R. However, when the adopted function number N is set to "1", and the manual operation target speed Vt1 remains greater than 0, the reset signal R is not output from the reset signal calculation unit 315.

[0096] Furthermore, for example, when the adopted function number N is set to "2" and the machine control unit 312 outputs an MC reset signal R2, the MC reset signal R2 is output from the reset signal calculation unit 315 as a post-arrangement reset signal R. In other words, when the machine control function is set as the highest priority function and the reset condition for the machine control function is met, the reset signal calculation unit 315 outputs an MC reset signal R2 as a post-arrangement reset signal R to reset the PID controller 318a and the target speed correction value Cv (see Figure 10), which will be described later. When the adopted function number N is set to "3" and the area control unit 313 outputs an AC reset signal R3, the AC reset signal R3 is output from the reset signal calculation unit 315 as a post-arrangement reset signal R. In other words, when the area control function is set as the highest priority function and the reset condition for the area control function is met, the reset signal calculation unit 315 outputs an AC reset signal R3 as a post-arrangement reset signal R to reset the PID controller 318a and the target speed correction value Cv (see Figure 10), which will be described later.

[0097] When the adopted function number N switches from "2" to "3", the AC reset signal R3 is output from the reset signal calculation unit 315 as a post-arbitration reset signal R. Similarly, when the adopted function number N switches from "3" to "2", the MC reset signal R2 is output from the reset signal calculation unit 315 as a post-arbitration reset signal R. Likewise, when the adopted function number N switches from "1" to "2" or "3", and when the adopted function number N switches from "2" or "3" to "1", the reset signal calculation unit 315 outputs a post-arbitration reset signal R, and the PID controller 318a and the target speed correction value Cv (see Figure 10), which will be described later, are reset (initialized).

[0098] In this manner, the reset signal calculation unit 315 arbitrates the manual operation reset signal R1, the MC reset signal R2, and the AC reset signal R3 based on the adopted function number N calculated by the target speed arbitration unit 314.

[0099] Furthermore, the reset signal calculation unit 315 detects the switching of the adopted function number N and calculates the reset signal corresponding to the adopted function number N after the switch as the post-arrangement reset signal R. In other words, the reset signal calculation unit 315 outputs the post-arrangement reset signal R when the support function is enabled (when the support function transitions from an disabled state to an enabled state). Also, the reset signal calculation unit 315 outputs the post-arrangement reset signal R when the support function is disabled (when the support function transitions from an enabled state to an disabled state).

[0100] As shown in Figure 4, the actual speed calculation unit 319 calculates the actual speed (hereinafter also referred to as the actual actuator speed) Va of the hydraulic actuator (for example, the boom cylinder 204a) based on the detection result of the attitude detection device 156 and the dimensions of each part of the hydraulic excavator 901 stored in the non-volatile memory 300w. For example, the actual speed calculation unit 319 calculates the angular velocity of the boom 204 around the boom pin and calculates the extension / retraction speed (cylinder speed) of the boom cylinder 204a based on the calculated angular velocity. In this way, the speed of the hydraulic actuator can be calculated based on the detection result of the attitude detection device 156. For this reason, the IMU (attitude sensors) 212 to 216 of the attitude detection device 156 function as speed sensors that detect the actual speed of the hydraulic actuator. As mentioned above, if a stroke sensor of the hydraulic cylinder is provided as an attitude sensor, the stroke sensor functions as a speed sensor.

[0101] The unstable state determination unit 316 determines whether the state of the hydraulic actuator to be controlled is unstable based on the actual actuator speed Va calculated by the actual speed calculation unit 319, and calculates an unstable state flag Fb based on the determination result.

[0102] Referring to Figure 8, the processing details of the unstable state determination unit 316 will be explained in detail. Figure 8 is a block diagram of the operation of the unstable state determination unit 316. As shown in Figure 8, the unstable state determination unit 316 calculates acceleration by differentiating the actual actuator speed Va calculated by the actual speed calculation unit 319, and calculates jerk (rate of change) J by differentiating the acceleration. The unstable state determination unit 316 determines that the hydraulic actuator is not in an unstable state if the calculated jerk J of the hydraulic actuator is less than or equal to a predetermined threshold Jt. The unstable state determination unit 316 determines that the hydraulic actuator is in an unstable state if the calculated jerk J is greater than the predetermined threshold Jt. If the unstable state determination unit 316 determines that the hydraulic actuator is not in an unstable state, i.e., is in a stable state, it sets the unstable state flag Fb to "0". If the unstable state determination unit 316 determines that the hydraulic actuator is in an unstable state, it sets the unstable state flag Fb to "1".

[0103] The method for determining an unstable state is not limited to the method described above. For example, the unstable state determination unit 316 inputs the angles and speeds of each part of the hydraulic excavator 901 obtained from the detection results of the attitude detection device 156, as well as the pressures detected by the pump pressure detection device 151 and the actuator pressure detection device 152, into a machine learning model (such as a neural network, related vector regression, or random forest regression). Based on the input information, the machine learning model determines whether or not the state of the hydraulic actuator is unstable. Based on the determination result by the machine learning model, the unstable state determination unit 316 sets an unstable state flag.

[0104] As shown in Figure 4, the limit value calculation unit 317 calculates a limit value (post-arbitration limit value) to limit the target speed correction value Cv, which will be described later. Based on the adopted function number N calculated by the target speed arbitration unit 314, the MC limit value (MC upper limit value UL2 and MC lower limit value LL2) calculated by the machine control unit 312, the AC limit value (AC upper limit value UL3 and AC lower limit value LL3) calculated by the area control unit 313, and the unstable state flag Fb calculated by the unstable state determination unit 316, the limit value calculation unit 317 calculates the post-arbitration limit value (post-arbitration upper limit value UL and post-arbitration lower limit value LL).

[0105] Referring to Figure 9, the processing details of the limit value calculation unit 317 will be explained in detail. Figure 9 is a block diagram of the limit value calculation unit 317. As shown in Figure 9, the limit value calculation unit 317 includes a first limit value arbitration unit 317a, a second limit value arbitration unit 317b, a limit value determination unit 317c, and a rate limit processing unit 317d.

[0106] The first limit value arbitration unit 317a arbitrates the manual operation limit values ​​for the manual operation function (manual operation upper limit value UL1 and manual operation lower limit value LL1), the MC limit values ​​(MC upper limit value UL2 and MC lower limit value LL2), and the AC limit values ​​(AC upper limit value UL3 and AC lower limit value LL3) based on the adopted function number N set by the target speed arbitration unit. The manual operation upper limit value UL1 and manual operation lower limit value LL1 are stored in the non-volatile memory 300w. The MC upper limit value UL2 and MC lower limit value LL2 are input from the machine control unit 312. The AC upper limit value UL3 and AC lower limit value LL3 are input from the area control unit 313.

[0107] Specifically, the first limit value arbitration unit 317a selects and outputs the manual operation upper limit value UL1 and the manual operation lower limit value LL1 when the adopted function number N is set to "1". The first limit value arbitration unit 317a selects and outputs the MC upper limit value UL2 and the MC lower limit value LL2 when the adopted function number N is set to "2". The first limit value arbitration unit 317a selects and outputs the AC upper limit value UL3 and the AC lower limit value LL3 when the adopted function number N is set to "3".

[0108] The second limit arbitration unit 317b arbitrates between positive infinity (INF) as the upper limit and negative infinity (-INF) as the lower limit, and the unstable state upper limit UL0 and unstable state lower limit LL0, based on the unstable state flag Fb set by the unstable state determination unit 316.

[0109] Specifically, the second limit value arbitration unit 317b selects and outputs the upper limit value UL0 and the lower limit value LL0 of the unstable state when the unstable state flag Fb is set to "1". The second limit value arbitration unit 317b selects and outputs positive infinity as the upper limit value and negative infinity as the lower limit value when the unstable state flag Fb is set to "0".

[0110] The limit value determination unit 317c selects and outputs the smaller of the upper limit value output from the first limit value arbitration unit 317a and the upper limit value output from the second limit value arbitration unit 317b (i.e., the minimum value). The limit value determination unit 317c selects and outputs the larger of the lower limit value output from the first limit value arbitration unit 317a and the lower limit value output from the second limit value arbitration unit 317b (i.e., the maximum value).

[0111] Furthermore, the upper limit of the target speed correction value Cv is preferably a positive value, and its magnitude is preferably UL1 ≤ UL0 < UL3 < UL2. The lower limit of the target speed correction value is preferably a negative value, and its magnitude (absolute value) is preferably |LL1| ≤ |LL0| < |LL3| < |LL2|.

[0112] The rate limit processing unit 317d outputs the upper and lower limits output from the limit value determination unit 317c as the arbitrated upper limit UL and the arbitrated lower limit LL. Furthermore, if the upper and lower limits change due to a switch in the adopted function number N, the rate limit processing unit 317d performs rate limit processing to gradually change the upper and lower limits from the upper and lower limits before the change in the adopted function number N output from the limit value determination unit 317c to the upper and lower limits after the change in the adopted function number N output from the limit value determination unit 317c. In the rate limit processing, the upper and lower limits are gradually changed according to a preset rate of change per unit time. During rate limit processing, the rate limit processing unit 317d outputs the upper and lower limits that change with each calculation cycle as the arbitrated upper limit UL and the arbitrated lower limit LL.

[0113] Furthermore, during control by the support function, the limit value may change due to the support function. For example, the machine control unit 312 changes the limit value according to the work being performed by the hydraulic excavator 901. In cases where an intrusion prevention surface is set above the hydraulic excavator 901 to prevent the work device 203 from coming into contact with power lines or the like, the limit value set when the work device 203 approaches the intrusion prevention surface is different from the limit value set when the work device 203 is moved along the target excavation surface. The machine control unit 312 determines the work content and changes the limit value according to the work content. In such cases, the rate limit processing unit 317d does not perform the rate limit processing described above, but changes the limit value discontinuously. This makes it possible to perform appropriate control according to the work content.

[0114] Furthermore, when the unstable state flag Fb changes from "0" to "1," that is, when the state of the hydraulic actuator transitions from a stable state to an unstable state, it is preferable to immediately perform control to return to the stable state. Similarly, when the unstable state flag Fb changes from "1" to "0," that is, when the state of the hydraulic actuator transitions from an unstable state to a stable state, it is preferable to immediately perform control of the original function. For this reason, the rate limit processing unit 317d does not perform the rate limit processing described above, but changes the limit value discontinuously. This allows control to immediately return to the stable state when a transition occurs from a stable state to an unstable state. Also, when a transition occurs from an unstable state to a stable state, control of the original function can be immediately performed.

[0115] Thus, when the support function is activated, the rate limit processing unit 317d performs rate limit processing to gradually change the limit value (upper and lower limits) of the target speed correction value Cv calculated before activation to the limit value of the target speed correction value Cv calculated after activation, according to a predetermined rate of change per unit time. On the other hand, if the limit value changes due to the activated support function, the rate limit processing unit 317d does not perform rate limit processing. Furthermore, if the state of the hydraulic actuator transitions between a stable state and an unstable state, the rate limit processing unit 317d does not perform rate limit processing on the limit values ​​before and after the transition.

[0116] As shown in Figure 4, the command speed calculation unit 318 calculates a command speed Vc by correcting the post-arrangement target speed Vt, based on the post-arrangement target speed Vt calculated by the target speed arbitration unit 314, the actual actuator speed Va calculated by the actual speed calculation unit 319, the post-arrangement reset signal R calculated by the reset signal calculation unit 315, and the post-arrangement upper limit value UL and post-arrangement lower limit value LL calculated by the limit value calculation unit 317.

[0117] Referring to Figure 10, the processing details of the command speed calculation unit 318 will be explained in detail. Figure 10 is a block diagram of the command speed calculation unit 318. As shown in Figure 10, the command speed calculation unit 318 calculates the target speed correction value Cv by applying PID control (Proportional-Integral-Differential Controller) processing to the difference (speed deviation) between the arbitrated target speed Vt calculated by the target speed arbitration unit 314 and the actuator actual speed Va calculated by the actual speed calculation unit 319. The command speed calculation unit 318 calculates the command speed Vc, which is the corrected target speed, by adding the target speed correction value Cv to the arbitrated target speed Vt. The PID controller 318a consists of a proportional term, an integral term, and a differential term. PID control is a type of feedback control and is a well-known technology, so a detailed explanation will be omitted. In PID control, the target speed correction value Cv is "proportional gain K Ｐ × velocity deviation + integral gain K Ｉ × integral of velocity deviation + differential gain K Ｄ It is obtained by multiplying by the derivative of the velocity deviation.

[0118] If the reset signal calculation unit 315 outputs a post-arbitration reset signal R (when R = 1), the PID controller 318a resets the correction value calculated in the integral term and the target speed correction value Cv calculated by the PID controller 318a (Cv = 0). If the reset signal calculation unit 315 does not output a post-arbitration reset signal R (when R = 0), the PID controller 318a does not reset the correction value calculated in the integral term or the target speed correction value Cv calculated by the PID controller 318a.

[0119] Furthermore, the target speed correction value Cv calculated by the PID controller 318a has upper and lower limits determined by the arbitrated upper limit UL and arbitrated lower limit LL from the limit value calculation unit 317. If the target speed correction value Cv is greater than or equal to the arbitrated upper limit UL, the correction value limit unit 318b outputs the arbitrated upper limit UL as the target speed correction value Cv (Cv = UL). In other words, the target speed correction value Cv is limited to the arbitrated upper limit UL. If the target speed correction value Cv is less than or equal to the arbitrated lower limit LL, the correction value limit unit 318b outputs the arbitrated lower limit LL as the target speed correction value Cv (Cv = LL). In other words, the target speed correction value Cv is limited to the arbitrated lower limit LL. The correction value limiting unit 318b outputs the target speed correction value Cv without limiting it if the target speed correction value Cv is greater than the post-arrangement lower limit value LL and less than the post-arrangement upper limit value UL.

[0120] As shown in Figure 4, the valve control unit 320 controls the solenoid valve unit 113 based on the command speed Vc calculated by the command speed calculation unit 318 and the pressure P detected by the pressure detection device 157. The pressure detection device 157 includes a pump pressure detection device 151 and an actuator pressure detection device 152. Referring to Figure 5, the contents of the processing performed by the valve control unit 320 will be described in detail.

[0121] As shown in Figure 5, the valve control unit 320 includes a target flow rate calculation unit 321, a pump target flow rate calculation unit 322, a directional control valve target opening calculation unit 323, a flow control valve target opening calculation unit 324, a pump control command calculation unit 325, a directional control valve control command calculation unit 326, and a flow control valve control command calculation unit 327.

[0122] The target flow rate calculation unit 321 calculates the actuator target flow rate Qt, which is the target value of the flow rate of hydraulic fluid supplied to each hydraulic actuator, based on the command speed Vc calculated by the command speed calculation unit 318. The pump target flow rate calculation unit 322 calculates the pump target flow rate Qpt, which is the target value of the flow rate of hydraulic fluid discharged from hydraulic pumps 1 to 3, based on the actuator target flow rate Qt of each hydraulic actuator calculated by the target flow rate calculation unit 321. The pump control command calculation unit 325 calculates the flow rate control command (control current value) for hydraulic pumps 1 to 3 based on the pump target flow rate Qpt calculated by the pump target flow rate calculation unit 322 and outputs it to the pump solenoid valve. The pump solenoid valve is the solenoid valve 113a described above, etc.

[0123] The directional control valve target opening calculation unit 323 calculates the thrust of the hydraulic actuator based on the pressure (pump pressure and actuator pressure) detected by the pressure detection device 157 and the specifications of the hydraulic actuator stored in the non-volatile memory 300w (for example, the pressure-receiving area of ​​the hydraulic cylinder). The directional control valve target opening calculation unit 323 calculates the target opening area of ​​the directional control valve based on the actuator target flow rate Qt calculated by the target flow rate calculation unit 321 and the thrust of the hydraulic actuator. The directional control valve control command calculation unit 326 calculates the opening control command (control current value) for the directional control valve based on the target opening area of ​​the directional control valve calculated by the directional control valve target opening calculation unit 323 and outputs it to the solenoid valve for the directional control valve. The solenoid valve for the directional control valve is the solenoid valve 113b, 113c, etc. as described above.

[0124] The flow control valve target opening calculation unit 324 calculates the target opening area of ​​the flow control valve based on the actuator target flow rate Qt calculated by the target flow rate calculation unit 321 and the pressure (pump pressure and actuator pressure) detected by the pressure detection device 157. The flow control valve control command calculation unit 327 calculates the opening control command (control current value) for the flow control valve based on the target opening area of ​​the flow control valve calculated by the flow control valve target opening calculation unit 324 and outputs it to the solenoid valve for the flow control valve. The solenoid valve for the flow control valve is the solenoid valve 113d described above, etc.

[0125] Referring to Figure 11, an example of a process performed by the controller 300 will be described. The process shown in the flowchart of Figure 11 is started when an ignition switch (not shown) is turned on, and after initial settings (not shown) are performed, it is repeatedly executed at a predetermined calculation cycle.

[0126] As shown in Figure 11, in step S110, the controller 300 determines whether the operating device 150 is being operated based on the detection result (operation signal) of the manipulated quantity sensor. If it is determined that the operating device 150 is being operated, the process proceeds to steps S115 and S140. If it is determined that the operating device 150 is not being operated, the process proceeds to the next calculation cycle and executes the operation determination process (S110) again. In other words, the operation determination process (S110) is executed repeatedly until a positive determination is made.

[0127] In step S115, the manual operation control unit 311 calculates the manual operation target speed Vt1 of the hydraulic actuator based on the operation signal.

[0128] In the next step S120, the controller 300 determines whether at least one of the support functions, the machine control function and the area control function, is enabled based on the function activation flag Fa from the support function setting device 116. If it is determined that at least one of the machine control function and the area control function is enabled, the process proceeds to step S125. If it is determined that neither the machine control function nor the area control function is enabled, the process proceeds to step S135.

[0129] In step S125, the machine control unit 312 calculates the machine control target speed Vt2, and the area control unit 313 calculates the area control target speed Vt3.

[0130] In the next step S130, the target speed arbitration unit 314 arbitrates the manual operation target speed Vt1, the machine control target speed Vt2, and the area control target speed Vt3 based on the function activation flags Fa (Fa2, Fa3), and calculates the arbitrated target speed Vt (see Figure 6). Also in step S130, the target speed arbitration unit 314 calculates the adopted function number N based on the function activation flags Fa (Fa2, Fa3) (see Figure 6).

[0131] In the next step S135, the reset signal calculation unit 315 calculates the post-arrangement reset signal R based on the manual operation target speed Vt1, the MC reset signal R2, the AC reset signal R3, and the adopted function number N (see Figure 7).

[0132] In step S140, the instability determination unit 316 determines whether the control state of the hydraulic actuator is unstable or stable based on the actual actuator speed Va calculated by the actual speed calculation unit 319. If the instability determination unit 316 determines that the control state of the hydraulic actuator is unstable, it sets the instability flag Fb to "1 (on)". If it determines that the control state of the hydraulic actuator is stable, it sets the instability flag Fb to "0 (off)". (See Figure 8).

[0133] When the processing in steps S135 and S140 is completed, the process proceeds to step S150. In step S150, the limit value calculation unit 317 calculates the post-arbitration upper limit UL and post-arbitration lower limit LL based on the adopted function number N, the manual operation upper limit UL1 and manual operation lower limit LL1, the MC upper limit UL2 and MC lower limit LL2, the AC upper limit UL3 and AC lower limit LL3, the unstable state upper limit UL0 and unstable state lower limit LL0, and the unstable state flag Fb (see Figure 9).

[0134] In the next step S155, the command speed calculation unit 318 corrects the post-arbitration target speed Vt based on the actual actuator speed Va, the post-arbitration reset signal R, the post-arbitration upper limit UL, and the post-arbitration lower limit LL, and calculates the command speed Vc, which is the corrected target speed (see Figure 10).

[0135] In the next step S160, the target flow rate calculation unit 321 calculates the actuator target flow rate Qt based on the command speed Vc. Although notation is omitted here, the above calculation process is performed for each hydraulic actuator A, B, ... and calculates the target flow rates QtA, QtB, ... for each actuator.

[0136] Furthermore, in step S160, the target flow rate calculation unit 321 calculates the target meter-out flow rate Qto for each hydraulic actuator based on the operation signal. Although notation is omitted here, the above calculation process is performed for each hydraulic actuator A, B, ... to calculate the target meter-out flow rates QtoA, QtoB, ... for each actuator.

[0137] Furthermore, in step S160, the target flow rate calculation unit 321 calculates the target meter-in flow rate Qti for each hydraulic actuator based on the operation signal. Although notation is omitted here, the above calculation process is performed for each hydraulic actuator A, B, ... to calculate the target meter-in flow rates QtiA, QtiB, ... for each actuator.

[0138] In the next step S165, the pump target flow rate calculation unit 322 calculates the pump target flow rate Qpt as the sum of the actuator target flow rates Qt of each hydraulic actuator. Note that the pump target flow rate Qpt is not limited to being calculated using only the sum of the target flow rates of each hydraulic actuator. For example, the pump target flow rate calculation unit 322 may further consider the bleed-off flow rate, drain flow rate, etc., when calculating the pump target flow rate Qpt.

[0139] Furthermore, in step S165, the directional control valve target opening calculation unit 323 calculates the target meter-out opening area Ato of the directional control valve based on the target meter-out flow rate Qto, the required operating direction of the hydraulic actuator determined from the operation signal, and the target meter-out pressure Po. The target meter-out pressure Po is calculated using the attitude information detected by the attitude detection device 156.

[0140] Furthermore, in step S165, the flow control valve target opening calculation unit 324 calculates the target opening area Aft of the flow control valve based on the target meter-in flow rate Qti and the differential pressure ΔP across the flow control valve. For example, when extending the arm cylinder 205a, the differential pressure ΔP across the flow control valve 25 is calculated by subtracting the actuator pressure (load pressure) detected by the actuator pressure sensor 88a downstream of the flow control valve 25 from the pump pressure detected by the pump pressure sensor 85 upstream of the flow control valve 25. Alternatively, a pressure sensor (not shown) may be provided between the directional control valve and the flow control valve, and the differential pressure ΔP across the flow control valve may be calculated based on the detection result of this pressure sensor and the detection result of the pump pressure sensor.

[0141] In the next step S170, the pump control command calculation unit 325 outputs a flow rate control command to the pump solenoid valve (for example, solenoid valve 113a) corresponding to the pump target flow rate Qpt calculated in step S165. As a result, the command pressure is input from the pump solenoid valve to the command pressure chamber of the regulator, and the regulator controls the discharge flow rate of the hydraulic pump to become the pump target flow rate Qpt.

[0142] Furthermore, in step S170, the directional control valve control command calculation unit 326 outputs an opening control command to the solenoid valves for the directional control valve (for example, solenoid valves 113b, 113c) corresponding to the target meter-out opening area Ato calculated in step S165. As a result, a command pressure is input from the solenoid valves for the directional control valve to the command pressure chamber of the directional control valve, and the opening area on the meter-out side of the directional control valve is controlled to become the target meter-out opening area Ato.

[0143] Furthermore, in step S170, the flow control valve control command calculation unit 327 outputs an opening control command to the flow control valve solenoid valve (for example, solenoid valve 113d) corresponding to the target opening area Aft calculated in step S165. As a result, the command pressure is input from the flow control valve solenoid valve to the command pressure chamber of the flow control valve, and the opening area of ​​the flow control valve is controlled to become the target opening area Aft.

[0144] Once the processing in step S170 is complete, the series of processes shown in Figure 11 for this calculation cycle is finished. Note that the processes shown in the flowchart of Figure 11 are performed on all solenoid valves that generate the command pressure for all hydraulic pumps, directional control valves, and flow control valves.

[0145] An example of the operation of this embodiment will be described. First, an example of the operation when the support function is enabled from a state where it is disabled will be described.

[0146] <When support functions are disabled> When an operation signal (operated amount) corresponding to the operator's operation is input to the controller 300, the controller 300 calculates the manual operation target speed Vt1 according to the input operated amount. In manual operation, the operator operates the hydraulic excavator 901 by visually observing its movement and feeding the results back into the operator's own operation input. If the controller 300 applies strong correction through feedback control to the operator's operation input, that correction may be contrary to the operator's intention to operate, potentially causing a feeling of discomfort during operation. Therefore, in manual operation, the absolute values ​​of the upper and lower limits of the target speed correction value Cv are set to be small. This reduces the influence of the correction on the target speed. Feedback control is applied only when an operated amount is input, and if no operated amount is input, a manual operation reset signal is calculated and the target speed correction value Cv is reset.

[0147] <When the machine control function is activated> Next, when the machine control function is activated, the hydraulic excavator 901 operates according to the machine control target speed Vt2 calculated by the machine control unit 312. The purpose of machine control is to assist the operator's operation, and it is required to execute the desired operation with high precision. For this reason, in order to correct the machine control target speed Vt2 by feedback control in the controller 300, the magnitude (absolute value) of the upper and lower limits of the target speed correction value Cv is set to be relatively large.

[0148] In this embodiment, when the machine control function is enabled, rate limiting processing is applied to the switching between the upper and lower limits. Therefore, the upper and lower limits change gradually from the upper and lower limits during manual operation to the upper and lower limits of machine control. Since abrupt changes in the target speed correction value Cv are prevented, shocks to the operation of the hydraulic excavator 901 can be prevented.

[0149] In manual operation, the target speed correction value Cv is reset when no operation input is received, whereas in machine control, the controller 300 may drive the hydraulic actuator even when the operation lever is not being operated. Therefore, the reset conditions under which the machine control unit 312 outputs a reset signal are different from those for manual operation. In this embodiment, when the machine control function is enabled, the feedback control is reset using the MC reset signal calculated by the machine control unit 312. Here, the conditions for resetting the signal of the PID controller (integrator, etc.) 318a are assumed to be the timing when the manual operation function and the machine control function are switched, and the timing when the actuator target speed Vt2 calculated by the machine control unit 312 becomes 0.

[0150] The area control function operates similarly, so its explanation will be omitted. Next, we will describe an example of how the hydraulic actuator behaves when its behavior becomes unstable.

[0151] <When the control state of the hydraulic actuator becomes unstable> When the hydraulic actuator is operating and it is determined that the control state (operating state) of the hydraulic actuator is unstable, the controller 300 sets the upper limit (upper limit after arbitration) UL and lower limit (lower limit after arbitration) LL of the target speed correction value Cv to the unstable state upper limit UL0 and the unstable state lower limit LL0. The absolute values ​​of the unstable state upper limit UL0 and the unstable state lower limit LL0 are set to values ​​smaller than the upper limits (UL2, UL3) and lower limits (LL2, LL3) when stable feedback control is being performed by the support function (for example, 0).

[0152] Here, a larger target speed correction value Cv allows the actual speed Va to approach the command speed Vc in a shorter time, but if it becomes too large, it may cause vibration (hunting) in the hydraulic actuator. On the other hand, a smaller target speed correction value Cv takes longer to approach the command speed Vc from the actual speed Va, but it allows the hydraulic actuator to operate stably.

[0153] In this embodiment, if the hydraulic actuator becomes unstable during operation by the support function, the absolute value of the limit (upper and lower limit) of the target speed correction value Cv is reduced. In other words, if the actuator operation becomes unstable, the feedback control correction is weakened or disabled. Since the influence of the feedback control correction on the post-arrangement target speed Vt can be reduced, the control system can escape from an unstable state and stable actuator operation can be achieved.

[0154] According to the above-described embodiment, the following effects are achieved.

[0155] (1) The system includes hydraulic actuators (e.g., boom cylinder 204a, arm cylinder 205a) that drive the members to be driven (e.g., boom 204, arm 205), hydraulic pumps (1 to 3) that supply pressurized oil to the hydraulic actuators, flow control valves (e.g., flow control valves 23, 24, 28 for the first to third booms, flow control valves 25, 24 for the first and second arms) that control the flow rate of pressurized oil supplied from the hydraulic pumps to the hydraulic actuators, an operating device 150 that operates the members to be driven, a controller 300 that controls the flow control valves based on the operating signals of the operating device 150, and speed sensors (e.g., IMU 212, 213) that detect the actual speed Va of the hydraulic actuators.

[0156] The controller 300 has a manual operation function that calculates a manual operation target speed Vt1, which is the target speed of the hydraulic actuator, based on the operation signal of the operating device 150, and a support function (machine control function and area control function) that calculates a support target speed (machine control target speed Vt2 and area control target speed Vt3), which is a target speed different from the manual operation target speed Vt1. The controller 300 calculates the arbitrated target speed Vt of the hydraulic actuator by arbitrating the multiple target speeds Vt1 to Vt3 (see Figure 6). The controller 300 calculates a target speed correction value Cv, which is a correction value of the target speed, by feedback control (for example, PID control) based on the deviation (Vt-Va) between the arbitrated target speed Vt of the hydraulic actuator and the actual speed Va (see Figure 10). The controller 300 calculates the command speed (corrected target speed) Vc by correcting the arbitrated target speed Vt of the hydraulic actuator based on the target speed correction value Cv. The controller 300 controls the operation of the hydraulic actuator based on the command speed Vc. In other words, the controller 300 controls the flow control valve so that the hydraulic actuator operates at the command speed Vc.

[0157] When the support function is enabled from a disabled state, the controller 300 performs a process to reset the target speed correction value Cv (see Figure 7), and a process to limit the target speed correction value Cv based on limit values ​​(UL2, UL3, LL2, LL3) corresponding to the enabled support function (see Figure 9).

[0158] With this configuration, the manual operation function and support functions (machine control function and area control function) allow for appropriate correction of the post-arrangement target speed Vt by feedback control when the hydraulic actuator is operating. This makes it possible to control the hydraulic actuator stably and with high precision. In other words, according to this embodiment, it is possible to provide a hydraulic excavator 901 that can appropriately perform multiple functions (manual operation function and support function) without degrading the control performance of the hydraulic actuator.

[0159] (2) When the hydraulic actuator is operating due to the support function, the controller 300 executes a process to reset the target speed correction value Cv when the direction of operation of the hydraulic actuator changes (for example, when the direction of operation of the boom cylinder 204a changes from the extension direction to the retraction direction).

[0160] With this configuration, when the operating direction of the hydraulic actuator changes from a first direction (e.g., extension direction) to a second direction (e.g., contraction direction), the target speed of the hydraulic actuator operating in the second direction is not corrected by the target speed correction value Cv calculated when the hydraulic actuator was operating in the first direction. Therefore, the hydraulic actuator operating in the second direction can be controlled appropriately.

[0161] (3) The above limit values ​​have upper limits (UL2, UL3) and lower limits (LL2, LL3). The controller 300 limits the target speed correction value Cv to the upper limit when the target speed correction value Cv calculated by feedback control is greater than or equal to the upper limit. The controller 300 limits the target speed correction value Cv to the lower limit when the target speed correction value Cv calculated by feedback control is less than or equal to the lower limit.

[0162] This configuration prevents the target speed correction value Cv from becoming too large or too small. This allows the hydraulic actuator to be controlled appropriately according to the support function.

[0163] (4) The controller 300 determines whether the hydraulic actuator is in a predetermined state based on the actual speed Va of the hydraulic actuator. The predetermined state is a state in which the hydraulic actuator is unstable. If the controller 300 determines that the hydraulic actuator is in the predetermined state, it sets the magnitude (absolute value) of the upper and lower limits to a value smaller than when it determines that the hydraulic actuator is not in the predetermined state (see Figure 9).

[0164] The magnitudes (absolute values) of the upper limit UL0 and lower limit LL0 of the unstable state are smaller than the magnitudes (absolute values) of the upper limits (UL2, UL3) and lower limits (LL2, LL3) when stable feedback control is being performed by the support function.

[0165] With this configuration, if the hydraulic actuator becomes unstable during operation under the assistance function, the impact of feedback control correction on the target speed can be minimized. This allows the hydraulic actuator's operation to be stabilized before returning to operation in accordance with the assistance function.

[0166] Although an example has been described in which the magnitude (absolute value) of the limit values ​​(upper and lower limits) of the target speed correction value Cv is reduced after the state of the hydraulic actuator becomes unstable, the present invention is not limited to this. The magnitude of the limit values ​​of the target speed correction value Cv may be reduced when it is predicted that the state of the hydraulic actuator will become unstable.

[0167] In other words, the above-mentioned predetermined state may be a state in which the hydraulic actuator is expected to become unstable. With this configuration, it is possible to appropriately prevent the hydraulic actuator from becoming unstable when it is operating due to the support function.

[0168] (5) The controller 300 calculates the jerk J based on the actual speed Va of the hydraulic actuator. The controller 300 determines that the hydraulic actuator is in the predetermined state if the jerk J is greater than a predetermined threshold Jt. The threshold Jt when the predetermined state is defined as a state in which instability is expected should be set to a smaller value than the threshold Jt when the predetermined state is defined as an unstable state.

[0169] While a machine learning model could be used to determine the predetermined state described above, creating such a model requires considerable time and cost. In contrast, this embodiment allows the determination of the predetermined state based on the actual speed Va of the hydraulic actuator. This means that the time and cost required for prior preparation can be reduced.

[0170] (6) The controller 300 calculates the arbitrated target speed Vt by arbitrating the manual operation target speed Vt1 and multiple support target speeds (machine control target speed Vt2, area control target speed Vt3) based on a predetermined priority order (see Figure 6). Based on the priority order, the controller 300 determines the highest priority function, which is the function that should be given the most priority among the multiple functions. For example, when the machine control function is enabled and the area control function is disabled, the machine control function is determined as the highest priority function. Also, when both the machine control function and the area control function are enabled, the area control function is determined as the highest priority function. The controller 300 executes a process to reset the target speed correction value Cv when the reset condition for the highest priority function is met (see Figures 7 and 10). The controller 300 also executes a process to limit the target speed correction value Cv based on the limit value of the highest priority function (see Figures 9 and 10).

[0171] This configuration allows the hydraulic actuator to be operated at speeds corresponding to the priority of multiple functions. Furthermore, since the target speed correction value Cv is reset when the reset condition for the highest priority function is met, the hydraulic actuator can be operated stably and with high precision by the highest priority function. Similarly, since the target speed correction value Cv is limited based on the limit value of the highest priority function, the hydraulic actuator can be operated stably and with high precision by the highest priority function.

[0172] (7) When the support function is activated, the controller 300 performs rate limiting processing, which gradually changes the limit values ​​(upper and lower limits) of the target speed correction value Cv calculated before activation to the limit values ​​(upper and lower limits) of the target speed correction value Cv calculated after activation, according to a predetermined amount of change per unit time (see Figure 9).

[0173] This configuration prevents abrupt changes in the target speed correction value Cv caused by switching functions, thereby preventing shocks from occurring in the operation of the hydraulic excavator 901.

[0174] (8) The controller 300 does not perform rate limiting processing if the limit value changes due to the activated support function. This allows the support function to apply limits appropriately and the hydraulic actuator to operate appropriately according to the support function.

[0175] (9) When the state of the hydraulic actuator transitions between a predetermined state and a state other than the predetermined state, the controller 300 does not perform rate limit processing on the limit values ​​before and after the transition. This allows, for example, if an unstable state occurs, control to immediately transition to a stable state to be performed, and once a stable state is achieved, control to the original function to be performed immediately to be returned.

[0176] The following modifications are also within the scope of the present invention, and it is possible to combine the configurations shown in the modifications with the configurations described in the embodiments described above, or to combine the configurations described in the following different modifications.

[0177] <Variation 1> The arbitration process for the target speed is not limited to the example described above.

[0178] <Modification 1-1> The target speed arbitration unit 314 may, for example, calculate the arbitrated target speed Vt by assigning weights to multiple target speeds according to their priority in the target speed arbitration process and calculating a weighted average. The weight coefficients are set to be larger the higher the priority. The relationship between the weight coefficient w1 of the manually operated target speed Vt1, the weight coefficient w2 of the machine-controlled target speed Vt2, and the weight coefficient w3 of the area-controlled target speed Vt3 is w1 < w2 < w3.

[0179] <Modification 1-2> Also, as shown in Figure 12, when the machine control function is activated, the target speed arbitration unit 314 may arbitrate between the manually operated target speed and the machine control target speed based on the arbitration ratio of the machine control, and when the area control function is activated, it may arbitrate based on the upper and lower limits of the target speed using the upper and lower speed limits of the area control function.

[0180] <Modification 2> In the above embodiment, an example was described in which the controller 300 is configured to perform both a reset process and a process to limit the target speed correction value based on a limit value. More specifically, in the above embodiment, an example was described in which the controller 300 is configured to perform both a process to reset the target speed correction value Cv when the reset condition of the highest priority function is met, and a process to limit the target speed correction value Cv based on the limit value of the highest priority function. However, the present invention is not limited thereto. The controller 300 may be configured to perform at least one of the reset process and the process to limit the target speed correction value Cv when the support function is activated.

[0181] <Modification 3> In the above embodiment, an example using PID control (proportional-integral-derivative control) as feedback control was described, but the present invention is not limited thereto. PI control (proportional-integral control) and PD control (proportional-derivative control) may also be used as feedback control.

[0182] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0183] 1...First hydraulic pump (hydraulic pump), 2...Second hydraulic pump (hydraulic pump), 3...Third hydraulic pump (hydraulic pump), 4...Hydraulic oil tank, 6...Directional control valve for right travel (directional control valve), 7...Directional control valve for bucket (directional control valve), 8...Directional control valve for second arm (directional control valve), 9...Directional control valve for first boom (directional control valve), 10...Directional control valve for second boom (directional control valve), 11...Directional control valve for first arm (directional control valve), 12...Directional control valve for first attachment (directional control valve), 13...Directional control valve for left travel (directional control valve), 14...Directional control valve for slewing (directional control valve) 15... Directional control valve for the third boom (directional control valve), 16... Directional control valve for the second attachment (directional control valve), 21... Flow control valve for the bucket (flow control valve), 22... Flow control valve for the second arm (flow control valve), 23... Flow control valve for the first boom (flow control valve), 24... Flow control valve for the second boom (flow control valve), 25... Flow control valve for the first arm (flow control valve), 26... Flow control valve for the first attachment (flow control valve), 27... Flow control valve for the swing (flow control valve), 28... Flow control valve for the third boom (flow control valve), 29... Flow control valve for the second attachment (flow control valve) 84-86...Pressure sensor (pump pressure sensor), 87a-90b...Pressure sensor (actuator pressure sensor), 111...Pilot pump, 113...Solenoid valve unit, 113a-113e...Solenoid valve, 115a, 115b...Operating lever, 116...Support function setting device, 133-137...Pressure sensor, 143-147...Current sensor, 150...Operating device, 151...Pump pressure detection device, 152...Actuator pressure detection device, 153...Temperature detection device, 154...Pilot pressure detection device, 155...Current detection device, 156...Attitude detection device, 157...Pressure detection device, 201...Travel body ,201L...Travel motor (hydraulic actuator, hydraulic motor), 202...Slewing body, 203...Working device, 204...Boom (Driven component), 204a...Boom cylinder (hydraulic actuator, hydraulic cylinder), 205...Arm (Driven component), 205a...Arm cylinder (hydraulic actuator, hydraulic cylinder), 206...Bucket (Driven component), 206a...Bucket cylinder (hydraulic actuator, hydraulic cylinder), 207...Operator's cab, 208...Machine room, 210...Control valve unit, 211...Slewing motor (hydraulic actuator, hydraulic motor),212-216...IMU (Attitude Sensor, Speed ​​Sensor), 217...Engine (Prime Motor), 220...Aircraft, 300...Controller, 300v...Processing Unit, 300w...Non-volatile Memory (Storage Device), 300x...Volatile Memory (Storage Device), 300y...Input Interface, 300z...Output Interface, 311...Manual Operation Control Unit, 312...Machine Control Unit, 313...Area Control Unit, 314...Target Speed ​​Arrangement Unit, 314a...First Speed ​​Selection Unit, 314b...Second Speed ​​Selection Unit, 314c...First Number Selection Unit, 314d...Second Number Selection Unit, 315...Reset Signal calculation unit, 315a...Manual operation reset signal calculation unit, 315b...Function switching determination unit, 315c...First reset signal selection unit, 315d...Second reset signal selection unit, 316...Unstable state determination unit, 317...Limit value calculation unit, 317a...First limit value arbitration unit, 317b...Second limit value arbitration unit, 317c...Limit value determination unit, 317d...Rate limit processing unit, 318...Command speed calculation unit, 318a...PID controller (controller), 318b...Correction value limit unit, 319...Actual speed calculation unit, 320...Valve control unit, 321...Target flow rate calculation unit, 322...Pump target flow rate calculation unit, 323...Directional control valve 324...Target opening calculation unit, 325...Flow control valve target opening calculation unit, 326...Pump control command calculation unit, 327...Directional control valve control command calculation unit, 901...Hydraulic excavator (working machine), 902...Hydraulic drive unit, Aft...Target opening area, Ato...Target meter-out opening area, Cv...Target speed correction value (correction value), Fa...Function activation flag, Fa2...Machine control function function activation flag, Fa3...Area control function function activation flag, Fb...Unstable state flag, J...Jar, Jt...Threshold, LL...Post-arrangement lower limit, LL0...Unstable state LL1...Manual operation lower limit, LL2...MC lower limit, LL3...AC lower limit, N...Function number, Po...Target meter-out pressure, Qpt...Pump target flow rate, Qt...Actuator target flow rate, Qti...Target meter-in flow rate, Qto...Target meter-out flow rate, R...Post-arrangement reset signal, R1...Manual operation reset signal, R2...MC reset signal, R3...AC reset signal, UL...Post-arrangement upper limit, UL0...Unstable state upper limit, UL1...Manual operation upper limit, UL2...MC upper limit, UL3...AC upper limit, Va...Actuator actual speed (actual speed of hydraulic actuator),Vc...Command speed, Vt...Post-arrangement target speed, Vt1...Manual operation target speed, Vt2...Machine control target speed, Vt3...Area control target speed

Claims

1. A work machine comprising: a hydraulic actuator for driving a member to be driven; a hydraulic pump for supplying pressurized oil to the hydraulic actuator; a flow control valve for controlling the flow rate of pressurized oil supplied from the hydraulic pump to the hydraulic actuator; an operating device for operating the member to be driven; a controller for controlling the flow control valve based on an operating signal from the operating device; and a speed sensor for detecting the actual speed of the hydraulic actuator, wherein the controller has a manual operation function for calculating a manual operation target speed, which is a target speed of the hydraulic actuator, based on an operating signal from the operating device; a support function for calculating a support target speed, which is a target speed different from the manual operation target speed; a work machine for calculating a post-arrangement target speed of the hydraulic actuator by arbitrating a plurality of target speeds; a correction value for the target speed for the hydraulic actuator by feedback control based on the deviation between the post-arrangement target speed and the actual speed of the hydraulic actuator; a command speed for the hydraulic actuator by correcting the post-arrangement target speed based on the correction value; and the flow control valve for controlling the hydraulic actuator to operate at the command speed. The controller is characterized in that, when the support function is enabled, it performs at least one of the following: a process to reset the correction value, and a process to limit the correction value based on a limit value corresponding to the enabled support function.

2. The work machine according to claim 1, wherein the controller performs a process to reset the correction value when the direction of operation of the hydraulic actuator changes while the hydraulic actuator is operating due to the support function.

3. A work machine according to claim 1, wherein the limit value has an upper limit and a lower limit, and the controller limits the correction value to the upper limit when the correction value calculated by the feedback control is greater than or equal to the upper limit, and limits the correction value to the lower limit when the correction value calculated by the feedback control is less than or equal to the lower limit.

4. A work machine according to claim 3, wherein the controller determines whether the hydraulic actuator is in a predetermined state based on the actual speed of the hydraulic actuator, and if it determines that the hydraulic actuator is in the predetermined state, it sets the magnitudes of the upper limit and the lower limit to values ​​smaller than when it is determined that the hydraulic actuator is not in the predetermined state, and the predetermined state is a state in which the hydraulic actuator is expected to become unstable, or a state in which the hydraulic actuator is unstable.

5. The work machine according to claim 4, wherein the controller calculates the jerk based on the actual speed of the hydraulic actuator, and determines that the hydraulic actuator is in the predetermined state when the jerk is greater than a predetermined threshold.

6. The work machine according to claim 1, wherein the controller calculates the arbitrated target speed by arbitrating the manual operation target speed and a plurality of support target speeds based on a predetermined priority order, determines the highest priority function which is the function that should be given the most priority among a plurality of functions based on the priority order, and performs at least one of the following: a process to reset the correction value when the reset condition of the highest priority function is met, and a process to limit the correction value based on the limit value of the highest priority function.

7. The work machine according to claim 1, wherein the controller, when the support function is activated, performs rate limit processing to gradually change the limit value of the correction value calculated before activation to the limit value of the correction value calculated after activation, according to a predetermined amount of change per unit time, and does not perform the rate limit processing if the limit value changes due to the activated support function.

8. The work machine according to claim 4, wherein the controller, when the support function is activated, performs rate limit processing to gradually change the limit value of the correction value calculated before activation to the limit value of the correction value calculated after activation, according to a predetermined amount of change per unit time, and when the state of the hydraulic actuator transitions between a predetermined state and a state other than the predetermined state, does not perform rate limit processing on the limit values ​​before and after the transition.

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