JP6628971B2 - Excavator - Google Patents

Description

  The present invention relates to a shovel in which a turning mechanism for turning an upper turning body is electrically driven.

  BACKGROUND ART Conventionally, a shovel capable of performing a crane operation by providing a hanging hook on a bucket portion has been known (for example, Patent Document 1).

  Patent Literature 1 discloses a hydraulic excavator in which a shovel specification and a crane specification can be selected. In the crane specification, the discharge flow rate of a hydraulic pump is changed to a small flow rate, and the crane speed is controlled during a swing operation to reduce the crane speed. The operability in work has been improved.

  Conventionally, a shovel in which a turning mechanism is electrically driven is known, and various methods for controlling a turning electric motor that drives the turning mechanism have been proposed (for example, Patent Document 2).

JP 2012-157136 A JP 2009-68197 A

  However, the technology described in Patent Literature 2 and the like is a control method of a turning electric motor that assumes a shovel operation, and does not correspond to a need in a crane operation.

  In view of the above problems, an object of the present invention is to provide a shovel capable of improving operability when performing a crane operation when driving a turning mechanism with a turning electric motor.

To achieve the above object, in one embodiment, the shovel is
An undercarriage,
An upper revolving structure mounted on the lower traveling structure,
A turning electric motor for turning the upper turning body,
An operating device for performing a swing operation of the upper swing body,
A mode selection switch for performing an operation of selecting a crane operation mode,
A controller that executes speed control of the turning electric motor according to an operation amount in the operation device,
The controller is
When the crane operation mode is selected, the speed command value for the operation amount in the speed control is lower than when the crane operation mode is not selected, and the speed instruction value for the increase in the operation amount is smaller. It is characterized in that the fluctuation rate of the rate of increase of the value is reduced.

  According to the above-described embodiment, it is possible to provide a shovel capable of improving the operability when performing a crane operation when the turning mechanism is driven by the turning electric motor.

It is a side view of the hybrid shovel concerning one embodiment. It is a figure explaining the mode of the retractable hook used for crane work. It is a block diagram showing an example of composition of a drive system of a hybrid shovel. FIG. 2 is a block diagram illustrating an example of a configuration of a power storage system of the hybrid shovel. 4 is a graph illustrating an example of a relationship between a lever operation amount and a target rotation speed of a turning electric motor. 9 is a graph illustrating another example of the relationship between the lever operation amount and the target rotation speed of the turning electric motor. 6 is a graph showing characteristics of a turning acceleration of a turning mechanism (upper turning body) realized with respect to a lever operation amount and a lever change amount. 9 is a graph showing characteristics of a turning deceleration of a turning mechanism (upper turning body) realized with respect to a lever operation amount and a lever change amount.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

  First, a configuration of a hybrid shovel according to an embodiment of the present invention will be described. FIG. 1 is a side view showing a hybrid shovel according to the present embodiment.

  As shown in FIG. 1, an upper swing body 3 is mounted on a lower traveling body 1 of a hybrid shovel via a swing mechanism 2. A boom 4 is attached to the upper swing body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to the tip of the arm 5. The boom 4, the arm 5, and the bucket 6 as attachments are each hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 as hydraulic actuators. In addition, the upper revolving unit 3 is provided with a cabin 10 on which an operator (operator) rides, and is mounted with a power source such as an engine 11 (see FIG. 3) described later.

  The hybrid shovel according to the present embodiment is configured to be able to perform a crane operation in addition to a normal operation (an shovel operation). FIG. 2 is a view for explaining an embodiment of a retractable hook 6F used for crane work. FIG. 2A shows a state (stored state) of the retractable hook 6F during normal work (shovel work). FIG. 2 (b) shows a state of the retractable hook during the crane operation (a state where the hook is taken out).

  As shown in FIGS. 2 (a) and 2 (b), the retractable hook 6F is configured so that the arm 5 and the bucket 6 are rotatable around a predetermined axis on the base end side (opposite to the hook portion where a wire or the like is hung). Attached near the joint. As shown in FIG. 2A, the retractable hook 6F is stored between other structural members (such as a link member that connects the arm 5 and the bucket 6) during shovel work. Then, as shown in FIG. 2 (b), the retractable hook 6F is turned around the predetermined axis during crane operation so that the hook portion is directed downward in a state where the bucket 6 is fully closed. The crane operation is performed with the bucket 6 fully closed.

  FIG. 3 is a block diagram illustrating a configuration of a drive system of the hybrid shovel according to the present embodiment. In the figure, the mechanical power system is indicated by a double line, the high-pressure hydraulic line is indicated by a thick solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a thin solid line.

  The engine 11 and the motor generator 12 as an assist motor are connected to two input shafts of a speed reducer 13, respectively. A main pump 14 and a pilot pump 15 are connected to an output shaft of the speed reducer 13. That is, the engine 11 as the main drive unit and the motor generator 12 as the assist drive unit drive the main pump 14 and the pilot pump 15 via the speed reducer 13. A control valve 17 is connected to the main pump 14 via a high-pressure hydraulic line 16. An operating device 26 is connected to the pilot pump 15 via a pilot line 25. In addition, a power storage system 120 including a power storage device 19 (see FIG. 4) described later is connected to the motor generator 12 via an inverter 18.

  The engine 11 is an internal combustion engine as a main power source of the hybrid shovel according to the present embodiment, and is, for example, a diesel engine. The engine 11 is constantly operated during startup of the hybrid shovel according to the present embodiment.

  The motor generator 12 has both a function of a motor capable of performing an electric assist operation using electric power supplied from the power storage system 120 and a function of a generator capable of performing a power generation operation using the power of the engine 11. The motor generator 12 in the present embodiment is AC-driven by an inverter 20. The motor generator 12 can be configured by, for example, an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded inside the rotor.

  As described above, the speed reducer 13 has two input shafts and one output shaft, the drive shafts of the engine 11 and the motor generator 12 are connected to each of the two input shafts, and The drive shaft of the main pump 14 is connected. With this configuration, when the load on the main pump 14 is high (when the load is higher than the output of the engine 11), the motor generator 12 performs the electric assist operation, and in addition to the output of the engine 11, the motor generator 12 The output is transmitted to the main pump 14. The output of the engine 11 is transmitted to the motor generator 12 via the speed reducer 13, and the motor generator 12 performs a power generation operation.

  Control for switching between the electric assist operation (power running operation) and the power generation operation by the motor generator 12 is executed by a controller 30 described later.

  The main pump 14 is a hydraulic pump that supplies hydraulic oil to the control valve 17 via a high-pressure hydraulic line 16, and is, for example, a swash plate type variable displacement hydraulic pump. The main pump 14 can adjust the stroke length of the piston by changing the angle (tilt angle) of the swash plate, and can change the discharge flow rate, that is, the pump output. The swash plate of the main pump 14 is controlled by a regulator (not shown). The regulator changes the tilt angle of the swash plate in response to a change in control current for an electromagnetic proportional valve (not shown). For example, by increasing the control current, the regulator increases the tilt angle of the swash plate and increases the discharge flow rate of the main pump 14. In addition, by reducing the control current, the regulator reduces the tilt angle of the swash plate and reduces the discharge flow rate of the main pump 14.

  The control current of the regulator (electromagnetic proportional valve) is set (changed) by a control command from a controller 30 described later.

  The pilot pump 15 is a hydraulic pump for supplying pilot pressure to various hydraulic control devices via a pilot line 25, and is, for example, a fixed displacement hydraulic pump.

  The control valve 17 is a hydraulic control device that controls a hydraulic system in the hybrid shovel. The control valve 17 includes a hydraulic motor 1A (for right), a hydraulic motor 1B (for left), a boom cylinder 7, and an arm for the undercarriage 1 connected via a high-pressure hydraulic line in accordance with an operation input to the operation device 26. The hydraulic pressure (flow rate) supplied to various actuators such as the cylinder 8 and the bucket cylinder 9 is controlled. In the following description, the hydraulic motors 1A and 1B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 may be collectively referred to as a "hydraulic actuator".

  The operating device 26 is operating means for operating various actuators (a hydraulic actuator and a turning electric motor 21 as an electric actuator described later). The operating device 26 converts the pilot pressure (primary pilot pressure) supplied from the pilot line 25 into a pilot pressure (secondary pilot pressure) according to the operation content such as the operation amount and operation direction by the operator. Output. The operating device 26 is connected to the control valve 17 and the pressure sensor 29 via hydraulic lines 27 and 28, respectively.

  The control valve 17 operates a spool valve corresponding to each hydraulic actuator according to the secondary-side pilot pressure output from the operating device 26 to supply the hydraulic oil discharged from the main pump 14 to each hydraulic actuator. . The pressure sensor 29 converts the secondary-side pilot pressure input from the operation device 26 into an electric signal, and outputs the electric signal to a controller 30 described later.

  The operation device 26 includes a lever, a pedal, and the like. For example, the operation of the turning mechanism 2 (the turning electric motor 21 described later), the boom 4 (the boom cylinder 7), the arm 5 (the arm cylinder 8), and the bucket 6 (the bucket cylinder 9) may be performed by levers. The operation of the lower traveling body 1 (the hydraulic motors 1A and 1B) may be performed by a pedal.

  In addition, the hybrid shovel according to the present embodiment includes a turning electric motor 21 that turns the turning mechanism 2 (the upper turning body 3) to turn, and the turning mechanism 2 is motorized. The turning electric motor 21 which is an electric actuator is connected to the electric storage system 120 via the inverter 20. A resolver 22, a mechanical brake 23, and a turning speed reducer 24 are connected to a rotating shaft 21A of the turning electric motor 21.

  The turning electric motor 21 is configured to be able to realize both a power running operation for driving the turning mechanism 2 to turn and a regenerative operation for regenerative braking (turning braking by generating regenerative power) the turning mechanism 2. The turning motor 21 drives the turning mechanism 2 (the upper turning body 3) to turn via a turning speed reducer 24.

  The resolver 22 is an example of a known detecting unit that detects the rotation position (rotation angle) and rotation speed of the turning electric motor 21. The resolver 22 outputs a detection signal corresponding to the rotation position and the rotation speed of the turning electric motor 21 to the controller 30.

  Note that various known sensors can be applied as detection means for detecting the rotation position and rotation speed of the turning electric motor 21.

  The mechanical brake 23 is a mechanical braking unit that performs a turning brake on the turning mechanism 2 (the upper turning body 3). The mechanical brake 23 has a function of mechanically stopping the rotation shaft 21A of the turning electric motor 21 and keeping the turning state of the turning mechanism 2 (upper turning body 3) when the operation device 26 is not operated by the operator. To achieve.

  The power storage system 120 is a power supply unit that supplies drive power for the motor generator 12 and the turning motor 21 via the inverters 18 and 20, and stores power generated by the motor generator 12 and the turning motor 21 ( Charging). Details of the power storage system 120 will be described with reference to FIG.

  FIG. 4 is a block diagram illustrating an example of the configuration of the power storage system 120. Power storage system 120 includes power storage device 19 as one power storage unit, buck-boost converter 100, and DC bus 110 as another power storage unit.

  Power storage device 19 is any chargeable and dischargeable power storage means. For example, power storage device 19 may be a capacitor such as a lithium ion capacitor and an electric double layer capacitor. The power storage device 19 may be a secondary battery such as a lithium ion battery. Hereinafter, description will be continued on the assumption that a capacitor is employed as power storage device 19.

  The DC bus 110 is a power storage unit of a constant voltage, and is disposed between the inverters 18 and 20 and the buck-boost converter 100, and controls power transfer between the motor generator 12, the power storage device 19, and the turning motor 21. I do.

  The buck-boost converter 100 is disposed between the power storage device 19 and the DC bus 110 so that the voltage value of the DC bus 110 falls within a certain range according to the operation state of the motor generator 12 and the turning motor 21. Switching between step-up operation and step-down operation.

  The power storage system 120 includes a DC bus voltage detection unit 111 that detects a voltage value of the DC bus 110, a capacitor voltage detection unit 112 that detects a voltage value and a current value of the power storage device 19 (capacitor), and a capacitor current detection unit. 113 are provided. The DC bus voltage value detected by the DC bus voltage detection unit 111 and the capacitor voltage value and the capacitor current value detected by the capacitor voltage detection unit 112 and the capacitor current detection unit 113 are supplied to the controller 30.

  Returning to FIG. 3, the hybrid shovel according to the present embodiment includes a controller 30 that executes drive control of the hybrid shovel. The controller 30 includes, for example, a microcomputer including a CPU (Central Processing Unit), an internal memory, and the like. Specifically, various control processes are executed by executing a drive control program stored in the internal memory on the CPU.

  The controller 30 executes drive control of the motor generator 12 (control for switching between the electric assist operation and the power generation operation by the motor generator 12) in accordance with, for example, an operation input to the operation device 26 and the rotation speed of the engine 11. . Further, the controller 30 controls the drive of the step-up / step-down converter 100. Specifically, based on a part or all of the information regarding the charging state of the power storage device 19, the operating state of the motor generator 12, the operating state of the turning electric motor 21, the voltage of the DC bus 110, etc. Control for switching between operation and step-down operation (charge / discharge control of power storage device 19) may be performed.

  The step-up operation is an operation of moving the electric energy of the capacitor to the DC bus 110 to increase the voltage of the DC bus 110, and the step-down operation is an operation of moving the electric energy of the DC bus 110 to the power storage device 19 and This is an operation of lowering the voltage of 110. Control for switching between the step-up operation and the step-down operation of the buck-boost converter 100 is performed by the DC bus voltage detection unit 111, the capacitor voltage detection unit 112, and the capacitor current detection unit 113 respectively detecting the DC bus voltage value and the capacitor voltage value. , And the capacitor current value.

  Further, the controller 30 converts a signal supplied from the pressure sensor 29 (a signal corresponding to an operation amount for turning the turning mechanism 2) into a speed command, and controls driving of the turning electric motor 21. For example, in response to the speed command, the controller 30 performs feedback control for feeding back a detected value of the rotation speed of the turning electric motor 21 input from the resolver 22. Then, the controller 30 generates a torque control command (torque command) to be generated in the turning motor 21 by feedback control, and drives the inverter 20 according to the torque command to thereby control the driving of the turning motor 21 ( Speed control).

  Note that such feedback control may be arbitrary such as, for example, PI control, PID control, proportional control, and integral control.

  When the operator selects the crane operation mode set as the operation mode at the time of performing the above-described crane operation, the controller 30 executes drive control specific to the crane operation mode, as described later. At this time, the controller 30 executes control to maintain the bucket 6 in the fully closed state regardless of the operation content of the operation device 26 (lever).

  The controller 30 is connected to a mode selection switch 40 provided for an operator to select a crane operation mode. The controller 30 can determine whether or not the crane operation mode is selected by receiving a signal regarding the selection state of the crane operation mode output from the mode selection switch 40.

  Next, the characteristic operation of the hybrid shovel according to the present embodiment, that is, the drive control of the turning electric motor 21 by the controller 30 when the crane operation mode is selected will be described.

  In this description, the contents of the drive control when the crane operation mode is not selected (in the case of the normal operation mode) will also be described as a premise.

  First, a method of setting a target rotation speed in speed control of the turning electric motor 21 by the controller 30 according to the present embodiment will be described.

  FIG. 5 is a graph illustrating an example of the relationship between the lever operation amount and the target rotation speed of the turning electric motor 21. Specifically, the relationship between the lever operation amount and the target rotation speed of the turning electric motor 21 in the normal operation mode is a thin solid line, and the relationship between the lever operation amount and the target rotation speed of the turning electric motor 21 in the crane operation mode is a thick solid line. Expressed by

  Note that the relationship of the graphs does not matter whether the turning mechanism 2 (the upper turning body 3) is turned to the left or to the right. The same applies to FIGS. 6 to 8 described below. The lever operation amount is represented by a ratio [%] to the full stroke. The maximum swing speed of the swing mechanism 2 (upper swing body 3) in the normal operation mode is ω1 [rad / s], and the maximum swing speed of the swing mechanism 2 (upper swing body 3) in the crane work mode is ω2 [rad / s]. s] (<ω1). Further, the range where the lever operation amount is 0% to Lo% is set as at least one of the dead zone region and the zero speed command region. The dead zone region is a region in which a speed command and a torque command for lever operation are not generated, that is, the drive control of the turning electric motor 21 is not performed, and the mechanical brake 23 holds the stopped state of the turning mechanism 2 (the upper turning body 3). Area. The zero speed command area is a buffer area for improving operability when switching the turning mechanism 2 (upper revolving unit 3) from the stopped state to the turning state, and sets the speed command to zero. In the following description, the relationship between the lever operation amount and the target rotation speed in a region other than the dead zone and the zero speed command region (hereinafter, referred to as a turning drive region) will be mainly described.

  As described above, in the hybrid shovel according to the present embodiment, the target rotation speed is determined according to the operation amount (lever operation amount) of the operation device 26, and the speed command and the torque command are determined so that the target rotation speed is realized. Is generated.

  In the case of the normal operation mode, in a region where the lever operation amount in the turning drive region is relatively small, the target rotation speed is set in a manner to increase relatively slowly as the lever operation amount increases. That is, the ratio of the increase in the target rotation speed to the increase in the lever operation amount is set relatively small. On the other hand, in a region where the lever operation amount is relatively large, the target rotation speed is set so as to increase relatively rapidly as the lever operation amount increases. That is, the ratio of the increase in the target rotation speed to the increase in the lever operation amount is set to be relatively large. Therefore, as shown in FIG. 5, the graph showing the target rotation speed with respect to the lever operation amount is represented by a downwardly convex curve or a broken line, and the point at which the target rotation speed is 0 indicated by the dashed line and the maximum turning speed ω1 Greatly deviates from the straight line connecting the points. In other words, the rate of change of the ratio of the increase in the target rotation speed to the increase in the lever operation amount in the turning drive region is set to be relatively large. This realizes a continuity of a response to a command when performing a turning operation with a relatively low turning speed and a small turning angle while achieving a relatively high maximum turning speed ω1 with a limited lever stroke length. That's why.

  On the other hand, in the crane operation mode, the target rotation speed with respect to the lever operation amount is set to be lower in the entire turning drive area than in the normal operation mode. Further, as shown in FIG. 5, although the graph showing the target rotation speed with respect to the lever operation amount shows a downwardly convex curve or a broken line, the target rotation speed shown by the two-dot chain line is lower than that in the normal operation mode. It is approaching a straight line connecting the point at 0 and the point at the maximum turning speed ω2. In other words, the rate of change of the ratio of the increase in the target rotation speed to the increase in the lever operation amount in the turning drive region is set to be relatively small. As a result, the relationship between the lever operation amount and the realized rotation speed of the swing mechanism 2 (upper swing body 3), which is the target rotation speed, becomes substantially linear. Speed adjustment becomes easier. In particular, since the continuity of the change of the turning speed with respect to the lever operation amount in the connection area between the low-speed area and the high-speed area increases compared to the conventional art, even if the lever operation is performed across such a connection area, the command changes suddenly. There is no adverse effect on the suspended load suspended on the retractable hook 6F. In the crane operation mode, a high turning speed is not required, and the maximum turning speed ω2 is set sufficiently smaller than the maximum turning speed ω1 in the normal operation mode. it can.

  In the case of the crane operation mode, as shown in FIG. 6 (a graph showing another example of the relationship between the lever operation amount and the target rotation speed of the turning electric motor 21), the turning mechanism 2 (upper part) realized by the lever operation amount The rotation speed of the revolving superstructure 3) may be a perfect linear relationship with the target rotation speed. That is, the ratio of the increase in the target rotation speed to the increase in the lever operation amount in the turning drive region may be set to be constant in the entire turning drive region.

  Here, while the relationship between the lever operation amount and the target rotation speed in the turning operation of the turning mechanism 2 (the upper turning body 3) is approximated to be linear, the lower traveling body 1, the boom 4, and the arm 5 are operated. The relationship between the operation amount and the driving speed may be made closer to linear.

  In the crane operation mode, the tilt angle of the main pump 14 is set smaller than in the normal operation mode, and the discharge flow rate of the main pump 14 is reduced. Thereby, as a premise, the driving speed of each hydraulic actuator can be suppressed.

  In the case of the normal operation mode, the relationship between the operation amount of the lever or the pedal and the opening degree of the spool valve that supplies the hydraulic oil from the main pump 14 to each hydraulic actuator depends on the lever operation amount and the target rotation speed in the turning operation described above. It is often the same as the relationship. That is, in the region where the operation amount is relatively small, the ratio of the increase in the opening of the spool valve to the increase in the operation amount is relatively small, and in the region where the operation amount is relatively large, the ratio of the opening of the spool valve to the increase in the operation amount is relatively small. The rate of increase is often set relatively high. In such a case, the fluctuation rate of the ratio of the increase in the opening of the spool valve to the increase in the operation amount of the lever or the pedal becomes relatively large.

  On the other hand, in the crane operation mode, the relationship between the increase in the operation amount and the increase in the opening of the spool valve is made closer to linear, that is, the opening of the spool valve with respect to the increase in the operation amount is higher than in the normal operation mode. The fluctuation rate of the rate of increase is made sufficiently small. Specifically, an adjustment valve or the like for adjusting the secondary-side pilot pressure output from the operation device 26 (lever or pedal) in accordance with a control command from the controller 30 is provided, and the pilot valve adjusted by the adjustment valve is provided. It is preferable to configure a hydraulic circuit or the like that can supply pressure to the spool valve. Thus, when the crane operation mode is selected, the characteristics of the pilot pressure supplied to the spool valve can be changed. When the spool valve is realized by an electromagnetic switching valve, the characteristic of the command signal output from the controller 30 to the electromagnetic switching valve (spool valve) may be changed in the crane operation mode.

  As described above, in the crane operation mode, the relationship between the operation amount and the opening degree of the spool valve corresponding to the flow rate of the hydraulic oil to the hydraulic actuator approaches linearly, so the lower traveling body 1 driven by the hydraulic actuator, the boom 4 , And the drive speed of the arm 5 can be easily adjusted.

  Next, a control method (acceleration control of the turning electric motor 21) of the turning acceleration (rotation acceleration of the turning electric motor 21) of the turning mechanism 2 (the upper turning body 3) by the controller 30 according to the present embodiment will be described.

  First, as a first example, when the crane operation mode is selected, control for changing the upper limit of the turning acceleration (and the turning deceleration) or the upper limit of the torque (drive torque / braking torque) for the turning electric motor 21 is performed. The method will be described.

  The controller 30 normally determines whether the generated torque command corresponds to acceleration / deceleration exceeding an upper limit value (upper limit turning acceleration) of a predetermined turning acceleration (and turning deceleration), or an upper limit value of torque for the turning electric motor 21 ( If the torque command exceeds the upper limit torque, the torque command is corrected (limited) and output. That is, a torque command corresponding to acceleration / deceleration that does not exceed the upper limit turning acceleration or a torque command that is equal to or less than the upper limit torque for the turning electric motor 21 is output. For example, in the case of the normal work mode, the upper limit turning acceleration or the upper limit torque is set based on the rated torque of the turning electric motor 21 and the like.

  In the present embodiment, when the crane operation mode is selected, the upper limit turning acceleration or the upper limit torque is set sufficiently smaller than in the normal operation mode. Thereby, when performing a crane operation, even if a sudden lever operation is performed, the swing mechanism 2 (the upper swing body 3) can be slowly accelerated and decelerated.

  Subsequently, as a second example, when the crane operation mode is selected, the swing of the swing mechanism 2 (the upper swing body 3) realized with respect to the lever operation amount and the lever change amount (change amount of the lever operation amount). A control method for changing the characteristics of the acceleration and the turning deceleration will be described.

  FIG. 7 is a graph showing the characteristics of the turning acceleration of the turning mechanism 2 (the upper turning body 3) realized with respect to the lever operation amount and the lever change amount. FIG. 7A is a graph showing the relationship between the lever operation amount and the acceleration ratio of the swing mechanism 2 (the upper swing body 3), and FIG. 7B is a graph showing the relationship between the lever change amount and the swing mechanism 2 (the upper swing body). It is a graph which shows the relationship with the acceleration ratio of 3). FIG. 8 is a graph showing the characteristics of the turning deceleration of the turning mechanism 2 (the upper turning body 3) realized with respect to the lever operation amount and the lever change amount. FIG. 8A is a graph showing the relationship between the lever operation amount and the speed reduction ratio of the swing mechanism 2 (upper swing body 3), and FIG. 8B is a graph showing the lever change amount and the swing mechanism 2 (upper swing body 3). It is a graph which shows the relationship with the deceleration ratio of 3). In each figure, a thin solid line represents the case of the normal operation mode, and a thick solid line represents the case of the crane operation mode.

  The acceleration ratio is a ratio of a lever operation amount to be compared with a reference acceleration (a reference lever operation amount or a turning acceleration in a lever change amount) or a ratio of a turning acceleration in a lever change amount. The reference acceleration in FIG. 7A is the turning acceleration when the lever operation amount is Lo% (start point of the turning drive area), and the reference acceleration in FIG. 7B is the turning acceleration when the lever change amount is 100%. . The deceleration ratio is a ratio of a lever operation amount to be compared to a reference deceleration (a reference lever operation amount or a turning deceleration in a lever change amount) or a turning deceleration in a lever change amount. The reference deceleration in FIG. 8A is the turning deceleration when the lever operation amount is 100% (the end point of the turning drive area), and the reference deceleration in FIG. 8B is the turning when the lever change amount is 100%. Deceleration. The reference acceleration and the reference deceleration when the crane operation mode is selected are set sufficiently smaller than those in the normal operation mode.

  First, the turning acceleration will be described with reference to FIG.

  In the case of the normal operation mode, as shown in FIG. 7A, the acceleration ratio (turning acceleration) of the turning mechanism 2 (upper turning body 3) is made sufficiently large as the lever operation amount in the turning drive region increases. Go. Thereby, it is possible to give the operator a feeling (acceleration feeling) that the acceleration increases in accordance with the increase in the lever operation amount toward the relatively high maximum turning speed ω1. Further, as shown in FIG. 7B, as the lever change amount decreases, the acceleration ratio (turning acceleration) of the turning mechanism 2 (the upper turning body 3) is sufficiently reduced. Thus, for example, when a lever operation with a relatively small lever change amount is performed from a state where the lever operation amount is relatively large, it is possible to avoid a situation in which the turning speed is not smoothly changed due to overshoot or the like. Can be.

  On the other hand, in the crane operation mode, as shown in FIG. 7A, the acceleration of the turning mechanism 2 (upper revolving unit 3) with respect to the increase in the lever operation amount in the turning drive area is higher than in the normal operation mode. Decrease the rate of increase of the ratio (turning acceleration) (see the white arrow in the figure). That is, the rate of change of the turning acceleration with respect to an increase (change) in the lever operation amount is made smaller than in the normal operation mode. As a result, although the maximum swing speed ω2 in the crane operation mode is set relatively low, an excessive swing acceleration is realized in accordance with the increase in the lever operation amount, and the change in the swing speed is smoothly caused by overshoot or the like. A situation that is not performed can be avoided. Also, as shown in FIG. 7B, the rate of decrease in the acceleration ratio (turning acceleration) with respect to the decrease in the lever change amount is made smaller than in the normal operation mode (see the white arrow in the figure). That is, the change rate of the turning acceleration with respect to the decrease (change) of the lever change amount is made smaller than in the case of the normal operation mode. This makes it possible to improve the position followability of the turning mechanism 2 (the upper turning body 3) with respect to a change in the lever operation amount, which is regarded as important in the crane operation.

  Next, the turning deceleration will be described with reference to FIG.

  In the case of the normal operation mode, as shown in FIG. 8A, as the lever operation amount decreases, the deceleration ratio (turning deceleration) of the turning mechanism 2 (the upper turning body 3) is sufficiently reduced. Thus, as in the case of turning acceleration, it is possible to give the operator a feeling (deceleration feeling) that the deceleration increases according to the decrease in the lever operation amount. Further, as shown in FIG. 8B, as the lever change amount decreases, the deceleration ratio (turning deceleration) of the turning mechanism 2 (upper turning body 3) is sufficiently reduced. As a result, as in the case of the turning acceleration, it is possible to avoid a situation in which the turning speed is not smoothly changed due to overshoot or the like.

  On the other hand, in the crane operation mode, as shown in FIG. 8A, the deceleration ratio of the turning mechanism 2 (upper revolving unit 3) with respect to the decrease in the lever operation amount (turning reduction) is lower than in the normal operation mode. The rate of increase in speed is reduced (see the white arrow in the figure). That is, the fluctuation rate of the turning deceleration with respect to the decrease (change) of the lever operation amount is made smaller than in the case of the normal operation mode. Thus, as in the case of the turning acceleration, an excessive turning deceleration can be realized according to the decrease of the lever operation amount, and a situation in which the turning speed is not smoothly changed due to overshoot or the like can be avoided. Further, as shown in FIG. 8B, the rate of decrease in the deceleration ratio (turning deceleration) of the turning mechanism 2 (upper turning body 3) with respect to the decrease in the lever change amount is made smaller than in the normal operation mode. (See the white arrow in the figure). That is, the fluctuation rate of the turning deceleration with respect to the decrease (change) of the lever change amount is made smaller than in the normal operation mode. Thus, as in the case of the turning acceleration, the position following ability of the turning mechanism 2 (the upper turning body 3) to the change of the lever operation amount, which is regarded as important in the crane operation, can be improved.

  The controller 30 calculates the current turning acceleration based on the rotation speed of the turning electric motor 21 detected by the resolver 22, and calculates the current turning acceleration based on the relationship between the current turning acceleration and the characteristics shown in FIGS. The acceleration control according to the embodiment is executed. Further, the controller 30 changes the characteristics (profile) of the turning acceleration and the turning deceleration of the turning mechanism 2 (upper turning body 3) which are realized with respect to the lever operation amount and the lever change amount shown in FIGS. , May be realized in any mode. For example, it may be realized by changing a speed command for a target rotation speed, may be realized by changing a control gain in PI control or the like, or may be realized by correcting a generated torque command. May be.

  Next, the backlash compensation control by the controller 30 according to the present embodiment will be described.

  The turning electric motor 21 drives the turning mechanism 2 (the upper turning body 3) to turn via the turning speed reducer 24 as described above. The transmission mechanism that transmits the power of the turning electric motor 21 including the turning speed reducer 24 to the turning mechanism 2 has a certain amount of backlash (backlash). Since such backlash may have an adverse effect such as generating vibration, in the present embodiment, when the crane operation mode is selected, in the drive control of the swing mechanism 2 (the upper swing body 3), the backlash is generated. Perform compensation control.

  A known method may be arbitrarily applied to the backlash compensation control. For example, a method of adjusting a control gain in PI control or the like may be applied. This can suppress the occurrence of vibrations and the like due to backlash, thereby improving workability in the crane operation mode. Further, in the crane operation mode, since the suppression of vibration and the like and the position following ability to the operation are more important than the high responsiveness to the lever operation, the effect of the deterioration of the responsiveness due to the backlash compensation is very small.

  On the other hand, in the normal operation mode (shovel operation mode), high responsiveness of the turning electric motor 21 to the lever operation is required, so that the backlash compensation control is not executed.

  In general, when the backlash compensation control is performed, the responsiveness to the lever operation often deteriorates (for example, when the backlash compensation is performed by adjusting the control gain, the control gain is controlled in a manner to suppress the responsiveness. It is determined).

  As described above, the embodiments for carrying out the present invention have been described in detail. However, the present invention is not limited to the specific embodiments, and various modifications may be made within the scope of the present invention described in the appended claims. Can be modified and changed.

  For example, in the embodiment described above, the hybrid shovel is described as an example, but the present invention is not limited to this configuration. That is, any shovel having an electric turning mechanism may be used, and for example, an electric shovel driven by power supply from an external power supply may be used.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 1A, 1B Hydraulic motor 2 Slewing mechanism 3 Upper revolving body 4 Boom 5 Arm 6 Bucket 6F Retractable hook 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 12 Motor generator 13 Reduction gear 14 Main pump 15 Pilot pump 16 High-pressure hydraulic line 17 Control valve 18, 20 Inverter 19 Power storage device
Reference Signs List 21 turning electric motor 21A rotating shaft 22 resolver 23 mechanical brake 24 turning reduction gear 25 pilot line 26 operating device 27, 28 hydraulic line 29 pressure sensor 30 controller 40 mode selection switch 100 step-up / step-down converter 110 DC bus 111 DC bus voltage detecting unit 112 Capacitor voltage detector 113 Capacitor current detector 120 Power storage system

Claims (3)

An undercarriage,
An upper revolving structure mounted on the lower traveling structure,
A turning electric motor for turning the upper turning body,
An operating device for performing a swing operation of the upper swing body,
A mode selection switch for performing an operation of selecting a crane operation mode,
A controller that sets a target rotation speed according to an operation amount in the operation device and executes speed control of the turning electric motor,
The controller is
When the crane operation mode is selected, the target rotation speed for the operation amount is lower than when the crane operation mode is not selected, and the target rotation speed is increased for the increase in the operation amount. Characterized in that the rate of change of the ratio of
Excavator. The controller is
When the crane operation mode is selected, the rate of increase in the target rotation speed with respect to the increase in the operation amount is set to be more constant than when the crane operation mode is not selected. ,
The shovel according to claim 1. The controller is
When the crane operation mode is selected, in the speed control, the turning acceleration of the upper revolving unit with respect to a change in the operation amount and a change amount of the operation amount, as compared with a case where the crane operation mode is not selected. Characterized in that the rate of change of the turning deceleration is reduced.
The shovel according to claim 1.

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