JP2017082389A - Shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shovel that facilitates fine adjustment of a position of an attachment to the shovel.SOLUTION: A superstructure is mounted rotatably on a lower machinery. A revolving motor generates power for rotating the superstructure relative to the lower machinery. An actuator is operated by an operator, for detecting an operation amount from a neutral position. A controller generates an operation command value for commanding revolution speed or torque of the revolving motor based on the operation amount of the actuator, and the revolving motor is controlled based on the operation command value. The controller controls the revolving motor by changing a rate of change of the operation command value relative to the operation amount, based on a change with time of the operation amount.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an excavator.

  When the excavator turns, the command value of the turning speed or turning torque changes according to the operation amount of the operation lever. The excavator is used for various work such as excavation work and crane work. In the excavation work, the earth and sand held in the bucket at the excavation point is swiveled to the loading platform of the dump truck. In the crane work, the object to be transported is moved using a hook attached to the bucket. In excavation work, in order to increase work efficiency, improvement in turning speed is required. In crane work, improvement in operability for accurately positioning the hook is required.

  Patent Document 1 below discloses an excavator capable of adjusting the acceleration until the turning speed reaches the target speed. The shovel disclosed in Patent Document 1 includes an adjustment volume for adjusting the turning acceleration. The turning acceleration can be adjusted by the operator (operator) operating the adjustment volume. When the set value of the turning acceleration is large, the turning speed reaches the target speed in a short time. When the set value of the turning acceleration is small, the time until the turning speed reaches the target speed becomes long.

JP 2009-68197 A

  In the shovel disclosed in Patent Document 1, the operator must adjust the adjustment volume so that a preferable turning acceleration can be obtained according to work. Since the operator must operate the adjustment volume in addition to the operation of the operation lever, the operation becomes troublesome. Further, if the operation of the adjustment volume is forgotten, the upper swing body turns at a speed different from the speed assumed by the operator.

  An object of the present invention is to provide an excavator capable of reducing the troublesomeness of switching between an operation for increasing the turning speed and an operation for decreasing the speed and realizing good operability according to work.

According to one aspect of the invention,
A lower traveling body,
An upper revolving unit mounted on the lower traveling unit so as to be able to swivel;
A turning motor that generates power for turning the upper turning body with respect to the lower traveling body;
An operating device that is operated by an operator and detects an operation amount from a neutral position;
A controller that generates an operation command value for instructing a rotation speed or torque of the swing motor based on an operation amount of the operating device, and that controls the swing motor based on the operation command value;
The controller is
An excavator for controlling the swing motor by changing a rate of change of the operation command value with respect to the operation amount based on a time change of the operation amount is provided.

  The operator does not need to perform a specific operation other than the operation of the operating device in order to change the change rate of the operation command value with respect to the operation amount. For this reason, the operator is freed from the annoyance of performing other operations in addition to the operation of the operation device.

FIG. 1 is a side view of an excavator according to an embodiment. FIG. 2 is a block diagram of an excavator according to the embodiment. FIG. 3A is a schematic diagram of an operating device, and FIG. 3B is a control block diagram for performing drive control of a turning motor. FIG. 4 is a flowchart of control executed by the controller. FIG. 5A is a graph showing an example of the relationship between the elapsed time from the operation start time of the operation lever and the operation amount, and FIG. 5B is an operation command value for controlling the operation amount of the operating device and the swing motor. It is a graph which shows the relationship. FIG. 6A is a graph showing an example of the time change between the operation amount and the operation command value in the normal operation mode, and FIG. 6B is a graph showing an example of the time change between the operation amount and the operation command value in the fine operation mode. is there. FIG. 7A is a functional block diagram showing an example of the function of the controller, FIG. 7B is a functional block diagram showing an example of the function of the inverter control unit when the speed of the swing motor is controlled, and FIG. It is a functional block diagram which shows an example of the function of an inverter control part in case a motor carries out torque control. FIG. 8A is a functional block diagram illustrating an example of a shovel controller according to another embodiment. FIG. 8B is a functional block diagram illustrating an example of functions of the inverter control unit. FIG. 9 is a flowchart of processing executed by a shovel controller according to still another embodiment. FIG. 10A is a functional block diagram of a part of a shovel controller according to still another embodiment, and FIG. 10B is a graph showing an example of a filter characteristic of a low-pass filter. FIG. 11 is a block diagram of an excavator according to still another embodiment.

  In FIG. 1, the side view of the shovel by an Example is shown. An upper swing body 11 is mounted on the lower traveling body 10 so as to be capable of swinging. A boom 12, an arm 13, and a bucket 14 are connected to the upper swing body 11. The boom cylinder 15 drives the boom 12. The arm cylinder 16 drives the arm 13. The bucket cylinder 17 drives the bucket 14. A turning motor 18 mounted on the upper turning body 11 generates power for turning the upper turning body 11. An electric motor can be used as the turning motor 18. The controller 19 controls the turning motor 18. An operation device 20 that is operated by an operator is disposed on the upper swing body 11. The operation device 20 includes an operation lever 20A, for example, and detects an operation by the operator.

  Instead of the bucket 14, another attachment can be attached to the tip of the arm 13. Examples of attachments other than the bucket 14 include a crusher, a breaker, and a lifting magnet.

  FIG. 2 is a block diagram of an excavator according to the embodiment. The engine 30, the motor generator 31, and the main hydraulic pump 32 are connected to each other via a torque transmission mechanism 33. The motor generator 31 can perform a power generation operation and an electric operation (assist operation). During the power generation operation, the power of the engine 30 is transmitted to the motor generator 31. During the assist operation, power generated by the motor generator 31 is transmitted to the main hydraulic pump 32. The rotating shaft of the main hydraulic pump 32 is connected to the pilot pressure hydraulic pump 39.

  The motor generator 31 and the turning motor 18 are connected to the storage circuit 35 via inverters 34 and 36, respectively. Torque generated by the swing motor 18 is transmitted to the upper swing body 11 (FIG. 1) via the speed reducer 38. The turning motor 18 generates regenerative power when the turning speed of the upper turning body 11 is reduced.

  The main hydraulic pump 32 supplies hydraulic oil to the control valve 40. The pilot pressure hydraulic pump 39 supplies the primary pilot pressure to the operating device 20. The operation device 20 converts the primary pilot pressure into a secondary pilot pressure according to the operation situation. The secondary pilot pressure is supplied to the control valve 40 and the pressure sensor 21.

  The control valve 40 distributes hydraulic oil to the boom cylinder 15, arm cylinder 16, bucket cylinder 17, and hydraulic motors 22 and 23 according to the secondary pilot pressure. The hydraulic motors 22 and 23 drive the left and right crawlers of the lower traveling body 10 (FIG. 1). The pressure sensor 21 converts the secondary pilot pressure into an electrical signal. This electrical signal is input to the controller 19.

  The operation device 20 generates an electrical signal according to an operation amount related to the turning operation of the upper swing body 11. This electrical signal is input to the controller 19. Based on the electrical signals from the pressure sensor 21 and the operation device 20, the controller 19 performs operations related to raising and lowering the boom 12, opening and closing the arm 13, opening and closing the bucket 14, operation of the lower traveling body 10, and turning operation of the upper swing body 11. get information.

  The resolver 37 detects the rotation speed of the turning motor 18. This detection result is input to the controller 19.

  The power storage circuit 35 includes a power storage device and a step-up / down converter. DC power is supplied from the power storage device to the inverters 34 and 36 via the step-up / down converter. The electric power generated by the motor generator 31 and the regenerative electric power generated by the turning motor 18 are supplied to the storage circuit 35 via inverters 34 and 36, respectively. The power storage device is charged with these electric powers.

  When the controller 19 controls the inverter 34, the motor generator 31 performs a power generation operation or an assist operation. Further, the controller 19 controls the inverter 36 to drive the turning motor 18. The controller 19 performs charge / discharge control of the power storage circuit 35 according to the electric power required for the motor generator 31 and the turning motor 18 and the charge state of the power storage device.

  FIG. 3A shows a schematic diagram of the operation device 20. The operation device 20 includes two operation levers and two pedals. Operation with respect to the turning motor 18, the boom 12, the arm 13, and the bucket 14 is performed by the two operation levers. Operation with respect to the crawler of the lower traveling body 10 is performed by the pedal. FIG. 3A shows an operation lever 20 </ b> A that performs an operation on the turning motor 18. The operating lever 20A in the neutral position is indicated by a solid line. As indicated by a broken line, the operation lever 20A is tilted in the positive direction or the negative direction from the neutral position. For example, an operation in the positive direction corresponds to a right turn, and an operation in the negative direction corresponds to a left turn.

  The position sensor 20B detects the operation amount of the operation lever 20A, and outputs the detected operation amount OA. The operation amount OA is, for example, an electric signal.

  FIG. 3B shows a control block diagram for performing drive control of the turning motor 18. The operation amount OA output from the operation device 20 is input to the controller 19. The controller 19 transmits a control signal SC to the inverter 36. The inverter 36 supplies a drive current to the swing motor 18 based on the control signal SC. A measured value SR of the rotational speed detected by the resolver 37 is fed back to the controller 19. The controller 19 performs feedback control based on the rotation speed measurement value SR.

  Next, a control method of the excavator turning motor 18 (FIG. 2) according to the embodiment will be described with reference to FIG.

  FIG. 4 shows a flowchart of the control executed by the controller 19. In step S10, it is determined whether the current operation is the “normal operation” or the “fine operation” based on the time change of the operation amount OA when the operation is started from the neutral position. Here, “fine operation” means an operation suitable for finely adjusting the tip position of the attachment as compared with “normal operation”. If the operation lever 20A is tilted at a normal speed from the neutral position, this operation is determined to be a normal operation. If the operation lever 20A is tilted more slowly than the normal speed from the neutral position, this operation is performed. Is determined to be a fine operation. A detailed determination method as to whether or not the current operation is a fine operation will be described later with reference to FIG. 5A.

  If it is determined that the current operation is a fine operation, the turning motor 18 is controlled in the fine operation mode in step S11. If it is determined that the current operation is a normal operation, the turning motor 18 is controlled in the normal operation mode in step S12. In the fine operation mode, the swing motor 18 is controlled under the condition that the change rate of the target value of the rotation speed of the swing motor with respect to the operation amount OA is smaller than that in the normal operation mode. The fine operation mode and the normal operation mode are continued until the operation device 20 returns to the neutral position. A detailed control method in the fine operation mode and the normal operation mode will be described later with reference to FIG. 5B.

  Next, with reference to FIG. 5A, a method for determining whether the current operation is “normal operation” or “fine operation” will be described.

  FIG. 5A shows an example of the relationship between the elapsed time from the operation start time of the operation lever 20A (FIG. 3A) and the operation amount OA. The horizontal axis represents elapsed time, and the vertical axis represents the manipulated variable OA. The operation amount OA is 0 at the neutral position. When the operation lever 20A is tilted in the positive direction, the operation amount OA increases in the positive direction, and when the operation lever 20A is tilted in the negative direction, the operation amount OA increases in the negative direction. A determination operation amount OAj for determining whether the current operation is “normal operation” or “fine operation” is defined.

  When the operation lever 20A is tilted forward from the neutral position, the operation amount OA increases with time. A time change of the operation amount OA when the operation lever 20A is tilted in the normal direction at a normal speed is represented by a thick solid line OA1, and a change of the operation amount OA when the operation lever 20A is slowly tilted is represented by a thin solid line OA2. The inclination of the thin solid line OA2 is gentler than that of the thick solid line OA1.

  It is determined whether the current operation is a normal operation or a fine operation based on the temporal change rate of the operation amount OA during a period in which the absolute value of the operation amount OA is within a range smaller than the determination operation amount OAj. Specifically, when the time until the absolute value of the operation amount OA reaches the determination operation amount OAj from the neutral position is equal to or greater than the determination threshold tj, it is determined that the current operation is a fine operation, and the determination threshold tj If it is less, it is determined that the current operation is a normal operation.

  In the example illustrated in FIG. 5A, the operation indicated by the thick solid line OA1 is determined to be a normal operation, and the operation indicated by the thin solid line OA2 is determined to be a fine operation.

  Next, with reference to FIG. 5B, a control method of the turning motor 18 in the normal operation mode and the fine operation mode will be described.

  FIG. 5B shows the relationship between the operation amount OA of the controller 20 (FIGS. 3A and 3B) and the operation command value OC for controlling the turning motor 18 (FIG. 3B). The horizontal axis represents the operation amount OA, and the vertical axis represents the operation command value OC. The origin of the horizontal axis corresponds to the neutral position of the operation device 20. The operation command value OC is a value that commands a target value of the rotational speed of the turning motor 18, for example. As the operation command value OC, a value that commands a target value of torque generated by the swing motor 18 may be adopted. A region where the operation amount OA in FIG. 5B is positive indicates an operation command value OC for turning the turning motor 18 to the right, and a region where the operation amount OA is negative indicates an operation command value OC for turning the turning motor 18 to the left. Show.

  The controller 19 (FIG. 3B) stores information defining the relationship R1 between the operation amount OA and the operation command value OC in the normal operation mode (relationship during normal operation) R1, and the operation amount OA and the operation command value in the fine operation mode. Information defining a relationship with OC (a relationship during fine manipulation) R2 is stored. The operation amount OA defines a dead zone DZ1 during normal operation including a neutral position and a dead zone DZ2 during fine operation that includes the neutral position and is narrower than the dead zone DZ1 during normal operation.

  In the relationship R1 during normal operation, the operation command value OC is 0 within the range of the dead zone DZ1 during normal operation. When the absolute value of the operation amount OA exceeds the upper limit value of the dead zone DZ1 during normal operation, the operation command value OC is output. As the absolute value of the manipulated variable OA increases, the operation command value OC also increases. When the operation command value OC reaches the upper limit value OCM, even if the operation amount OA increases, the operation command value OC becomes constant at the upper limit value OCM.

  In the relationship R2 at the time of the fine operation, the operation command value OC is 0 within the range of the dead zone DZ2 at the time of the fine operation. When the absolute value of the operation amount OA exceeds the upper limit value of the dead zone DZ2 at the time of fine operation, the operation command value OC is output. As the absolute value of the manipulated variable OA increases, the operation command value OC also increases.

  It is determined whether the current operation is a normal operation or a fine operation within the range of the dead zone DZ2 at the time of the fine operation. That is, the determination operation amount OAj (FIG. 5A) is equal to or less than the upper limit value of the dead zone DZ2 at the time of fine operation. It is preferable that the upper limit value of the dead zone DZ2 at the time of the fine operation and the determination operation amount OAj (FIG. 5A) be the same value. If both are made the same, the turning motor 18 can be started immediately after it is determined that the current operation is a fine operation.

  When the operation amount OA exceeds the upper limit value of the dead zone DZ2 at the time of fine operation, the rate of change of the operation command value OC with respect to the operation amount OA in the relationship R2 at the time of fine operation exceeds the upper limit value of the dead zone DZ1 at the time of normal operation. The change rate of the operation command value OC with respect to the operation amount OA in the relationship R1 at the time of normal operation at that time is smaller. Further, the operation command value OC with respect to the operation amount OA in the relationship R2 in the fine operation is within a range from the operation amount OA exceeding the upper limit value of the dead zone DZ1 at the normal operation until the operation command value OC reaches the upper limit value OCM. The change rate is smaller than the change rate of the operation command value OC with respect to the operation amount OA in the relationship R1 during normal operation.

  In the range outside the dead zone DZ2 at the time of fine operation and inside the dead zone DZ1 at the time of normal operation, the motion command value OC in the relationship R2 at the time of fine operation is larger than the motion command value OC in the relationship R1 at the time of normal operation. . When the operation amount OA becomes slightly larger than the upper limit value of the dead zone DZ1 during normal operation, the operation command value OC in the relationship R2 during fine operation becomes equal to the operation command value OC in the relationship R1 during normal operation. . In a range where the operation amount OA is larger than the operation amount OA where both are equal, the operation command value OC in the relationship R2 during fine operation is smaller than the operation command value OC in the relationship R1 during normal operation.

  If it is determined in step S10 (FIG. 4) that the current operation is a normal operation, an operation command value OC is generated from the current operation amount OA based on the relationship R1 during the normal operation, and the operation command value OC. The turning motor 18 is controlled based on the above (step S12). If it is determined that the current operation is a fine operation, an operation command value OC is generated from the current operation amount OA based on the relationship R2 at the time of the fine operation, and the swing motor 18 is controlled based on the operation command value OC. (Step S11).

  Next, the operation of the turning motor 18 in the normal operation mode and in the fine operation mode will be described with reference to FIGS. 6A and 6B. 6A and 6B show an example in which the operation device 20 is operated in the positive direction (right turn direction). When the operation device 20 is operated in the negative direction, the sign of the operation amount OA shown in FIGS. 6A and 6B becomes negative, and the operation command value OC changes to a value indicating the left turning direction.

  FIG. 6A shows an example of a time change between the operation amount OA and the operation command value OC in the normal operation mode. In FIG. 6A, a thin solid line indicates the manipulated variable OA, and a thick solid line indicates the operation command value OC. Since the time for the operation amount OA to reach the determination operation amount OAj from the neutral position is shorter than the determination threshold tj, the operation shown in FIG. 6A is determined to be a normal operation. For this reason, the relationship R1 (FIG. 5B) during normal operation is applied to the generation of the operation command value OC.

  The operation command value OC is 0 until the operation amount OA reaches the upper limit value of the dead zone DZ1 during normal operation. When the operation amount OA exceeds the upper limit value of the dead zone DZ1 during normal operation, an operation command value OC is generated from the current operation amount OA based on the relationship R1 during normal operation (FIG. 5B). Based on this operation command value OC, swing motor 18 (FIG. 3B) is controlled.

  FIG. 6B shows an example of a time change between the operation amount OA and the operation command value OC in the fine operation mode. In FIG. 6B, the thin solid line indicates the operation amount OA, and the thick solid line indicates the operation command value OC. Since the time until the operation amount OA reaches the determination operation amount OAj from the neutral position is longer than the determination threshold value tj, it is determined that the operation illustrated in FIG. 6B is a fine operation. For this reason, the relationship R2 (FIG. 5B) at the time of fine manipulation is applied to the generation of the operation command value OC.

  The operation command value OC is 0 until the operation amount OA reaches the upper limit value of the dead zone DZ2 at the time of fine operation. When the operation amount OA exceeds the upper limit value of the dead zone DZ2 at the time of fine operation, an operation command value OC is generated from the current operation amount OA based on the relationship R2 at the time of fine operation (FIG. 5B). Based on this operation command value OC, swing motor 18 (FIG. 3B) is controlled.

  In the fine operation mode (FIG. 6B), the operation command value OC changes more slowly than the normal operation mode (FIG. 6A) even if the amount of change in the operation amount OA is the same. Further, in the fine operation mode (FIG. 6B), the operation command value OC is small except in the vicinity of the neutral position even if the operation amount OA is the same as in the normal operation mode (FIG. 6A).

  Next, the excellent effect of the above embodiment will be described. As shown in FIGS. 6A and 6B, in the fine operation mode, the operation command value OC changes more slowly than the normal operation mode even if the change amount of the operation amount OA is the same. For this reason, the operation of finely adjusting the position of the tip of the attachment can be easily performed.

  The relationship R2 (FIG. 5B) between the operation amount OA and the operation command value OC in the fine operation mode is the relationship R1 (FIG. 5B) between the operation amount OA and the operation command value OC in the normal operation mode. Compared to 5B), it is closer to a straight line. For this reason, at the time of fine operation, the response of the turning motor 18 linearly changes with respect to the operation of the operation bar. This improves the operability when finely adjusting the position of the tip of the attachment.

  Furthermore, in the above embodiment, the dead zone DZ2 (FIG. 5B) at the time of fine operation is narrower than the dead zone DZ1 at the time of normal operation. For this reason, when it is determined that the current operation is a fine operation, the start of movement of the swing motor 18 is quicker than in the normal operation. Usually, when performing a fine operation, the operation device 20 is frequently operated in the vicinity of the neutral position. When the dead zone is wide, the amount of each operation frequently performed near the neutral position must be increased. In the above embodiment, since the dead zone DZ2 at the time of fine operation is narrowed, the operability of frequent operations in the vicinity of the neutral position is improved.

  Further, in the above embodiment, when the operating device 20 is operated slowly from the neutral position, the swing motor 18 is controlled in the fine operation mode, and when operated at the normal speed from the neutral position, the swing motor 18 is controlled in the normal operation mode. The The operator does not need to operate a switch or the like in order to select either the fine operation mode or the normal operation mode. For this reason, it is relieved from the troublesome operation of selecting the operation mode, and it is possible to concentrate on the operation of the operation device 20. In addition, forgetting to operate the switch or the like can be prevented. Actually, when the operator wants to perform a minute operation, the operator starts moving the operation device 20 slowly. For this reason, an operation mode that matches the operator's intention is selected.

  FIG. 7A shows an example of a functional block diagram of the controller 19. The controller 19 includes a first operation command generation unit 51, a second operation command generation unit 52, a fine operation determination unit 53, an operation mode switching unit 54, and an inverter control unit 55. The current operation amount OA is input to the first operation command generation unit 51, the second operation command generation unit 52, and the fine operation determination unit 53.

  Information defining the relationship R1 (FIG. 5B) during normal operation between the operation amount OA and the operation command value OC is stored in the first operation command generation unit 51, and the second operation command generation unit 52 stores Information defining the relationship R2 (FIG. 5B) at the time of fine operation between the operation amount OA and the operation command value OC is stored. The first operation command generator 51 outputs an operation command value OC1 based on the current operation amount OA and the relationship R1 during normal operation. The second operation command generator 52 outputs the operation command value OC2 based on the current operation amount OA and the relationship R2 at the time of the fine operation. A target value for the rotational speed or target value for the torque of the swing motor 18 is commanded by the operation command values OC1 and OC2.

  The operation mode switching unit 54 selects one of the operation command value OC1 that is the output of the first operation command generation unit 51 and the operation command value OC2 that is the output of the second operation command generation unit 52, and the operation command value This is given to the inverter control unit 55 as OC.

  The fine operation determination unit 53 determines whether the current operation is a fine operation or a normal operation based on a temporal change in the current operation amount OA. A specific determination method is as described with reference to FIG. 5A. If it is determined that the current operation is a fine operation, the fine operation determination unit 53 causes the inverter control unit 55 to input the operation command value OC2 that is the output of the second operation command generation unit 52. The operation mode switching unit 54 is controlled. When it is determined that the current operation is a normal operation, the fine operation determination unit 53 is configured so that the operation command value OC1 output from the first operation command generation unit 51 is input to the inverter control unit 55. The operation mode switching unit 54 is controlled.

  The inverter control unit 55 generates a control signal SC to be supplied to the inverter 36 based on the operation command value OC. At this time, feedback control based on the measured value SR of the rotational speed of the swing motor 18 and the measured value I of the output current of the inverter 36 is performed. The inverter 36 supplies a drive current to the swing motor 18 based on the control signal SC. The turning motor 18 turns the upper turning body 11 via the speed reducer 38.

  FIG. 7B shows an example of a functional block diagram of the inverter control unit 55 when the speed of the swing motor 18 is controlled. Inverter control unit 55 includes a speed control unit 55A and a current control unit 55B. In the example shown in FIG. 7B, the target value of the rotational speed of the swing motor 18 is commanded by the operation command value OC.

  The measured value SR of the rotational speed of the swing motor 18 is fed back to the speed control unit 55A. The speed control unit 55A outputs a torque command value TC so that the line speed approaches the operation command value OC based on the operation command value OC that is the target value of the rotation speed and the measured value SR of the rotation speed.

  The measured value I of the output current of the inverter 36 is fed back to the current control unit 55B. Current control unit 56 provides control signal SC to inverter 36 based on torque command value TC and current measurement value I.

  FIG. 7C shows an example of a functional block diagram of the inverter control unit 55 when the torque of the swing motor 18 is controlled. Inverter control unit 55 includes a current control unit 55B. In the example shown in FIG. 7C, the target value of the torque of the swing motor 18 is commanded by the operation command value OC. The torque target value corresponds to the torque command value TC (FIG. 7B).

  The measured value I of the output current of the inverter 36 is fed back to the current control unit 55B. The current control unit 56 gives a control signal SC to the inverter 36 based on the torque target value commanded by the operation command value OC and the current measurement value I. When torque control is performed on the swing motor 18, the measured value SR (FIG. 7A) of the rotational speed of the swing motor 18 does not need to be used for feedback control.

  In the example shown in FIGS. 7A and 7B, when the fine operation determination unit 53 switches the operation mode switching unit 54, one of the fine operation mode and the normal operation mode is selected, and the swing motor 18 is controlled. Is called.

  Next, another embodiment will be described with reference to FIGS. 8A and 8B. Hereinafter, differences from the embodiment shown in FIGS. 1 to 7 will be described, and description of common configurations will be omitted.

  FIG. 8A shows an example of a functional block diagram of the shovel controller according to the present embodiment. In the embodiment shown in FIG. 8A, the controller 19 includes an additional torque generator 57. The additional torque generation unit 57 generates an additional torque command value TA corresponding to a static friction force when the upper swing body 11 starts turning from a stationary state. The additional torque command value TA is input to the inverter control unit 55 via the open / close switch 58.

  The inverter control unit 55 controls the swing motor 18 using a value obtained by adding the additional torque command value TA to the torque target value based on the operation command value OC1 as a new torque target value.

  The fine operation determination unit 53 controls the opening / closing operation of the opening / closing switch 58. When it is determined that the current operation is a fine operation, the open / close switch 58 is closed, and when it is determined that the current operation is a normal operation, the open / close switch 58 is opened. For this reason, when it is determined that the current operation is a fine operation, the torque command value given to the current control unit 56, that is, the target value of the torque generated by the swing motor 18 is the torque obtained from the operation amount OA. The target value is obtained by adding a torque corresponding to the static friction force.

  Even if the operator operates the operation device 20 and torque is generated in the swing motor 18, the swing motor 18 does not start turning if the torque is equal to or less than the torque corresponding to the static friction force. The turning motor 18 starts turning when the torque generated by the turning motor 18 exceeds the torque corresponding to the static friction force. In the embodiment shown in FIGS. 1 to 7B, when the upper swing body 11 is swung from the stationary state, the operator must increase the operation amount OA by a torque corresponding to the static friction force. In the embodiment shown in FIGS. 8A and 8B, the swing motor 18 is generated by adding a torque corresponding to the static frictional force, so that the upper swing body 11 can be started smoothly.

  FIG. 8B shows an example of a functional block diagram of the inverter control unit 55. The additional torque command value TA is input to the adder 55C. The adder 55C adds the torque command value TC output from the speed control unit 55A and the additional torque command value TA generated by the additional torque generation unit 57, and provides the result to the current control unit 55B. The torque command value given to the current control unit 55B, that is, the target value of the torque generated by the turning motor 18 is a value obtained by adding a torque corresponding to the static friction force to the target value of the torque obtained from the operation amount OA. .

  Next, still another embodiment will be described with reference to FIG. Hereinafter, differences from the embodiment shown in FIGS. 1 to 7B will be described, and description of common configurations will be omitted.

  FIG. 9 shows a flowchart of the control executed by the excavator controller 19 according to the present embodiment. The process of step S10 is the same as the process of step S10 shown in FIG. If it is determined in step S10 that the current operation is a fine operation, the operation mode is set to the fine operation mode in step S21. If it is determined in step S10 that the current operation is a normal operation, the operation mode is set to the normal operation mode in step S22.

  After the operation mode is set in step S21 and step S22, an operation command value OC is generated in step S23 based on the current operation amount OA and the operation mode. When the operation mode is the fine operation mode, the fine operation relation R2 (FIG. 5B) is applied to the generation of the operation command value OC. When the operation mode is the normal operation mode, the relationship R1 during normal operation (FIG. 5B) is applied to the generation of the operation command value OC.

  In step S24, it is determined whether or not the operating device 20 has returned to the neutral position. If the controller 20 has not returned to the neutral position, the process returns to step S23 and the generation of the operation command value OC is continued. When the operating device 20 returns to the neutral position, the operation mode is initialized in step S25. After the initial setting, the process returns to step S10 to determine whether or not the current operation is a fine operation.

  In the embodiment shown in FIG. 9, the operation mode is initialized when the operation device 20 returns to the neutral position. Therefore, switching from the fine operation mode to the normal operation mode and switching from the normal operation mode to the fine operation mode are performed without any special operation by the operator. When the operator stops or interrupts the current operation, the operator normally returns the operation device 20 to the neutral position. Therefore, it can be said that the control for initially setting the operation mode when the operation device 20 returns to the neutral position is a control in accordance with the will of the operator.

  Next, still another embodiment will be described with reference to FIGS. 10A and 10B. Hereinafter, differences from the embodiment shown in FIGS. 1 to 7 will be described, and description of common configurations will be omitted.

  FIG. 10A shows a functional block diagram of a part of the excavator controller 19 according to the present embodiment. In this embodiment, the operation amount OA is input to the first operation command generation unit 51, the second operation command generation unit 52, and the fine operation determination unit 53 via the low-pass filter 60. Low-pass filter processing is performed on the time waveform of the operation amount OA, and the swing motor 18 is controlled based on the operation amount OA after the low-pass filter processing. By arranging the low-pass filter 60, it is possible to control the turning motor 18 by eliminating the influence of the high-frequency component of the time waveform of the operation amount OA. The fine operation determination unit 53 varies the filter characteristics of the low-pass filter 60, for example, the cutoff frequency, when it is determined that the current operation is a fine operation and when it is determined as a normal operation.

  FIG. 10B shows an example of the filter characteristics of the low-pass filter 60. The horizontal axis represents frequency, and the vertical axis represents transmission coefficient. A solid line FP1 indicates the filter characteristic of the low-pass filter 60 during normal operation, and a broken line FP2 indicates the filter characteristic of the low-pass filter 60 during fine operation. In the example shown in FIG. 10B, the cutoff frequency during fine operation is lower than the cutoff frequency during normal operation. For this reason, when it is determined that the current operation is a fine operation, the followability of the operation command value OC with respect to the change in the operation amount OA is greater than when the current operation is determined to be a normal operation. descend.

  At the time of fine operation, by reducing the followability of the operation command value OC with respect to the change in the operation amount OA, the influence of the vibration and fluctuation of the operator's arm associated with the swing of the upper swing body 11 is eliminated. The operability can be improved.

  Next, still another embodiment will be described with reference to FIG. Hereinafter, differences from the embodiment shown in FIGS. 1 to 7 will be described, and description of common configurations will be omitted.

  FIG. 11 shows a block diagram of an excavator according to this embodiment. In the present embodiment, an output device 61 is disposed. The output device 61 outputs information in a manner that can be recognized by the operator. For example, information is output by displaying an image, generating sound, light, vibration, or the like.

  When the controller 19 determines that the current operation is a fine operation, the controller 19 outputs information indicating that the current operation is a fine operation to the output device 61. Thereby, the operator can easily recognize that the turning motor 18 is controlled in the fine operation mode.

  In the above embodiments, an electric motor is used as the turning motor 18. As another configuration, a hydraulic motor may be used as the swing motor. Further, an example in which the control valve 40 is driven by the secondary pilot pressure output from the operating device 20 has been shown. In addition, it is also possible to employ a configuration in which an electromagnetic valve is used as the control valve 40 and the operating device 20 outputs an electric signal for driving the electromagnetic valve. Further, as a signal for controlling the swing motor 18, a signal obtained by converting the secondary pilot pressure output from the operation device 20 into an electric signal by the pressure sensor 21 can be used.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Lower traveling body 11 Upper turning body 12 Boom 13 Arm 14 Bucket 15 Boom cylinder 16 Arm cylinder 17 Bucket cylinder 18 Swing motor 19 Controller 20 Operator 20A Operation lever 20B Position sensor 21 Pressure sensor 22, 23 Hydraulic motor 30 Engine 31 Electric power generation Machine 32 main hydraulic pump 33 torque transmission mechanism 34 inverter 35 power storage circuit 36 inverter 37 resolver 38 speed reducer 39 pilot pressure hydraulic pump 40 control valve 51 first operation command generator 52 second operation command generator 53 fine operation determination unit 54 Operation mode switching unit 55 Inverter control unit 55A Speed control unit 55B Current control unit 55C Adder 57 Additional torque generation unit 58 Open / close switch 60 Low pass filter 61 Output device DZ1 Dead band D during normal operation 2 fine operation when the dead zone OA operation amount OAj determined operation amount OC operation command value R1 normal relation during operation R2 at fine operation related SC control signal TA additional torque command value TC torque command value tj determination threshold

Claims (8)

A lower traveling body,
An upper revolving unit mounted on the lower traveling unit so as to be able to swivel;
A turning motor that generates power for turning the upper turning body with respect to the lower traveling body;
An operating device that is operated by an operator and detects an operation amount from a neutral position;
A controller that generates an operation command value for instructing a rotation speed or torque of the swing motor based on an operation amount of the operating device, and that controls the swing motor based on the operation command value;
The controller is
An excavator that controls the swing motor by changing a rate of change of the operation command value with respect to the operation amount based on a time change of the operation amount. In the process of changing the rate of change of the operation command value with respect to the operation amount, the controller
Based on the time change rate of the operation amount when the operation is started from the neutral position, it is determined whether the current operation is a normal operation or a fine operation. The excavator according to claim 1, wherein a rate of change of the operation command value with respect to the operation amount is reduced as compared with a case where the operation is determined. The controller is
Storing information defining a relationship during normal operation and a relationship during fine operation between the operation command value and the operation amount;
In the relationship during the fine operation, the rate of change of the operation command value with respect to the operation amount is smaller than the relationship during the normal operation,
In the process of reducing the rate of change of the operation command value with respect to the operation amount, if it is determined that the current operation is a normal operation, the current operation amount is calculated based on the relationship during the normal operation. An operation command value is generated, and when it is determined that the current operation is a fine operation, the operation command value is generated from the current operation amount based on the relationship during the fine operation. The excavator described. The operation amount includes a dead zone during normal operation including the neutral position, and a dead zone during fine operation that includes the neutral position and is narrower than the dead zone during the normal operation.
In the relationship of the normal operation, the operation command value becomes 0 within the range of the dead zone at the time of the normal operation, and when the operation amount exceeds the upper limit value of the dead zone at the time of the normal operation, the operation command Value is output,
In relation to the fine operation, when the operation command value becomes 0 within the dead zone during the fine operation and the operation amount exceeds the upper limit of the dead zone during the fine operation, the operation command value is output. And
The shovel according to claim 2 or 3, wherein the controller determines whether the current operation is a normal operation or a fine operation within a range of a dead zone at the time of the fine operation. The controller is
When it is determined that the current operation is a fine operation, a torque corresponding to a static friction force when the upper swing body starts a swing operation is added to a torque based on the operation command value to control the swing motor The shovel according to any one of claims 2 to 4. The controller is
3. When the current operation is determined to be a fine operation, the followability of the operation command value with respect to the change in the operation amount is reduced as compared with a case where the current operation is determined to be a normal operation. The excavator of any one of thru | or 5.   When the controller detects that the operation amount has returned to 0, it initializes a result of determining whether the current operation is a normal operation or a fine operation, and whether the current operation is a normal operation. The shovel according to any one of claims 2 to 6, wherein a process for determining whether the operation is a fine operation is executed. An output device that outputs information in a manner recognizable by the operator;
8. The controller according to claim 2, wherein when the current operation is determined to be a fine operation, the controller outputs information indicating that the current operation is a fine operation to the output device. 9. Excavator.

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