JP7455738B2 - excavator - Google Patents

Description

The present disclosure relates to an excavator with an electric turning mechanism.

Conventionally, in excavators that drive the rotating structure using an electric motor, technology has been developed to emergency stop the rotating structure when an operator detects an abnormality and performs a predetermined operation (for example, operating a gate lock lever) while turning. It has been proposed (for example, Patent Document 1).

By adopting this configuration, the operator can sense an abnormality and perform a predetermined operation such as lowering the gate lock lever to bring the rotating structure to an emergency stop. safety can be increased.

Japanese Patent Application Publication No. 2012-82607

However, in order to further improve safety, it is desirable to detect the abnormality and perform fail-safe processing in response to the abnormality before the operator senses the abnormality.

In view of the above-mentioned problems, the present invention aims to provide higher safety in an excavator that electrically drives a revolving structure.

To achieve the above object, in one embodiment of the present disclosure,
A rotating body,
An electric motor that drives the rotating body,
When the information regarding the operating state of the gate lock lever indicates the locked state of the gate lock lever , an abnormality regarding the operation of the rotating structure is detected based on the information regarding the operation of the rotating structure, or the rotating structure is Determine whether to stop
A shovel will be provided.

According to the above-described embodiment, higher safety can be provided in an excavator that electrically drives a revolving structure.

It is a side view of an excavator. FIG. 2 is a diagram showing an example of the configuration of a shovel. FIG. 2 is a diagram showing an example of a configuration of a power storage system of an excavator. FIG. 2 is a functional block diagram schematically showing an example of the configuration of a swing control system of an excavator. It is a flowchart which shows roughly an example of the 1st monitoring processing by a controller (monitoring part). It is a flowchart which shows roughly another example of the 1st monitoring process by a controller (monitoring part). It is a flowchart which shows roughly an example of the 2nd monitoring processing by a controller (monitoring part). It is a flowchart which shows roughly another example of the 2nd monitoring processing by a controller (monitoring part). It is a figure showing other examples of the composition of an excavator. FIG. 3 is a functional block diagram showing another example of the configuration of the swing control system of the excavator. It is a flow chart which shows roughly an example of the 1st monitoring processing by a monitoring device.

Embodiments will be described below with reference to the drawings.

[Shovel configuration]
First, the configuration of the excavator according to this embodiment will be explained with reference to FIGS. 1 to 4.

FIG. 1 is a side view showing an excavator according to this embodiment.

As shown in FIG. 1, an upper rotating body 3 is mounted via a rotating mechanism 2 on a lower traveling body 1 which is hydraulically driven by travel hydraulic motors 1A and 1B (see FIGS. 2 and 7) as hydraulic actuators. Ru. A boom 4 is attached to the upper revolving 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, arm 5, and 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. Further, the upper revolving body 3 is provided with a cabin 10 in which an operator rides, and an engine 11 (see FIGS. 2 and 7) and the like are mounted thereon.

Figure 2 is a block diagram showing an example of the configuration of the excavator, focusing on the drive system, according to this embodiment.

In the figure, the mechanical power system is shown as a double line, the high pressure hydraulic line is shown as a thick solid line, the pilot line is shown as a broken line, and the electric drive/control system is shown as a thin solid line.

An engine 11 (for example, a diesel engine that uses light oil as fuel) as a main drive unit of the excavator according to the present embodiment and a motor generator 12 as an assist drive unit are connected to two input shafts of a reduction gear 13, respectively. Ru. A main pump 14 and a pilot pump 15 are connected in series to the output shaft of the reducer 13 . That is, the engine 11 can drive the main pump 14 and the pilot pump 15 via the reduction gear 13, and the motor generator 12 can drive the main pump 14 and the pilot pump 15 by assisting the engine 11. A control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16.

The main pump 14 is, for example, a variable displacement hydraulic pump, and can adjust the stroke length of the piston and control the discharge flow rate (discharge pressure) by controlling the angle (tilt angle) of the swash plate.

The pilot pump 15 is, for example, a fixed capacity hydraulic pump. Pilot pump 15 is connected to operating device 26 via pilot line 25.

The control valve 17 is a hydraulic control device that controls the hydraulic system in accordance with the operation of the operating device 26 by the operator. The travel hydraulic motors 1A (right), 1B (left), boom cylinder 7, arm cylinder 8, bucket cylinder 9, etc. are connected to a control valve 17 via a high-pressure hydraulic line. The control valve 17 is provided between the main pump 14 and each hydraulic actuator, and includes a plurality of hydraulic control valves (direction switching valves) that control the flow rate and flow direction of hydraulic oil supplied from the main pump 14 to each hydraulic actuator. ).

The operating device 26 includes levers 26A, 26B and a pedal 26C, and is an operation input means by which an operator operates each operating element (lower traveling structure 1, upper rotating structure 3, boom 4, arm 5, bucket 6, etc.). be. In other words, the operating device 26 includes hydraulic actuators (traveling hydraulic motors 1A, 1B, boom cylinder 7, arm cylinder 8, bucket cylinder 9, etc.) that drive each operating element and an electric actuator (swivel electric motor 21) to be described later. This is an operation input means for performing operations such as. The operating device 26 (levers 26A, 26B, and pedal 26C) is connected to the control valve 17 and the pressure sensor 29 via a hydraulic line 27 and a hydraulic line 28, respectively. As a result, a pilot signal (pilot pressure) is input to the control valve 17 in accordance with the operating states of the lower traveling body 1, the boom 4, the arm 5, the bucket 6, etc. in the operating device 26. Pressure sensor 29 is connected to controller 30. Thereby, a pressure signal (pressure detection value) corresponding to the operation state of the lower traveling body 1, the upper rotating body 3, the boom 4, the arm 5, the bucket 6, etc. in the operating device 26 is input to the controller 30.

Note that the levers 26A and 26B are arranged on the left and right sides, respectively, as viewed from the operator seated in the cockpit in the cabin 10, and are moved in the front-rear direction and the left-right direction with reference to a neutral state (a state in which no operation is performed). Constructed so that it can be tilted. That is, the upper rotating body 3, the boom 4, and the arm 5 are tilted in the front-rear direction, the lever 26A in the left-right direction, the lever 26B in the front-rear direction, and the lever 26B in the left-right direction. , and bucket 6 can be arbitrarily set as the operation target. The following explanation will be based on the premise that the operation pattern of the levers 26A and 26B is a JIS (ISO) pattern, that is, the operation of the upper rotating body 3 is performed by tilting the lever 26A from the neutral state in the left and right direction. I do.

Further, a gate lock switching valve 36 is provided in the pilot line 25 between the pilot pump 15 and the operating device 26.

The gate lock switching valve 36 changes the communication state of the pilot line 25 depending on the operating state of the gate lock lever 32, which is an operating section for opening and closing a gate provided in the entry/exit area to the pilot seat in the cabin 10. Switch the disconnected state. Specifically, the gate lock switching valve 36 operates according to a gate lock lever signal (ON/OFF) output from a gate lock lever switch (gate lock lever SW) 34 that is linked to the operating state of the gate lock lever 32. This is an electromagnetic switching valve that switches ON/OFF of an electromagnetic solenoid. The gate lock lever SW34 is turned OFF when the gate lock lever 32 is lowered (the access area to the cockpit is opened). When the gate lock switching valve 36 receives a gate lock lever signal indicating an OFF state (voltage signal below a predetermined threshold voltage) from the gate lock lever SW 34, the gate lock switching valve 36 puts the pilot line 25 into a disconnected state, and the pilot pump 15 The supply of hydraulic oil to the operating device 26 is cut off. On the other hand, the gate lock lever SW34 is turned ON when the gate lock lever 32 is raised (the access area to the cockpit is closed). When a gate lock lever signal indicating an ON state (a voltage signal higher than a predetermined threshold voltage) is inputted from the gate lock lever SW 34, the gate lock switching valve 36 brings the pilot line 25 into communication state, and connects the pilot line 25 to the pilot pump 15. Hydraulic oil (pilot pressure) is supplied to the operating device 26. When the gate lock lever 32 is raised, it can be determined that the operator is seated in the cockpit and is ready to operate the vehicle. Therefore, the pilot pressure is supplied to the operating device 26 only when the gate lock lever 32 is pulled up, thereby preventing each hydraulic actuator from operating due to an unintended operation input to the operating device 26. That is, when the gate lock lever is lowered, the operation of each hydraulic actuator is locked, and when the gate lock lever is raised, the operation of each hydraulic actuator is unlocked. Hereinafter, the state in which the gate lock lever 32 is lowered will be referred to as a "locked state", and the state in which the gate lock lever 32 is raised will be referred to as an "unlocked state".

In addition, in the figure, the gate lock switching valve 36 represents the case where the gate lock lever 32 is raised (gate lock lever SW34 is turned on), and pilot pressure is supplied from the pilot pump 15 to the operating device 26. has been done.

A power storage system 120 including a capacitor 19 (see FIG. 3) as an example of a power storage device is connected to the motor generator 12 via an inverter 18A.

Further, in the excavator according to the present embodiment, the swing mechanism 2 is motorized, and a swing electric motor 21 that drives the swing mechanism 2 (namely, the upper rotating body 3) is provided. Swing electric motor 21 is connected to power storage system 120 via inverter 18B. Further, the swing electric motor 21 performs regenerative power generation in accordance with the swing deceleration operation of the upper swing structure 3. A resolver 22, a mechanical brake 23, and a swing speed reducer 24 are connected to the rotating shaft 21A of the swing electric motor 21.

The turning electric motor 21 is configured to be capable of realizing both a power running operation in which the upper revolving structure 3 is driven to swing and a regenerative operation in which the upper revolving structure 3 is regeneratively braked (swinging braking is performed by generating regenerative power). During power running, the power of the swing electric motor 21 is increased by the swing reducer 24 (that is, the drive torque is increased), and the upper swing structure 3 is driven to swing. Furthermore, during regenerative operation (that is, when rotating and decelerating the upper rotating structure 3), the inertial rotational force of the upper rotating structure 3 is transmitted to the swing electric motor 21 via the swing reduction gear 24 to generate regenerative power ( In other words, the upper revolving body 3 is braked for swinging). The turning electric motor 21 according to this embodiment is driven by three-phase AC power supplied from the inverter 18B. The turning electric motor 21 can be configured to include, for example, an IPM (Interior Permanent Magnet) motor. Thereby, a larger induced electromotive force can be generated, so that the electric power generated by the turning electric motor 21 can be increased during regenerative braking.

The resolver 22 (an example of a speed detection section) is a known detection means that detects the rotational position (rotation angle), rotational speed, etc. of the turning electric motor 21. The resolver 22 transmits a detection signal (detection value) corresponding to the detected rotation angle and rotation speed to the controller 30.

Note that any sensor (for example, an encoder, etc.) may be used instead of the resolver 22 as long as the rotation angle and rotation speed of the turning electric motor 21 can be detected.

The mechanical brake 23 is a known mechanical braking means for braking the upper rotating body 3 from turning. The mechanical brake 23 generates a braking force torque by surface contact between a disk that rotates integrally with the rotating shaft 21A and is movable in the direction of the rotating shaft 21A (e.g., splined to the rotating shaft 21A) and a plate that does not rotate and is movable in the direction of the rotating shaft 21A (e.g., splined to the inner surface of the case, which is the fixed part). The mechanical brake 23 mechanically stops the rotating shaft 21A of the rotating motor 21 and can hold the upper rotating body 3 in a stopped state. In addition, the mechanical brake 23 can decelerate and stop the rotating mechanism 2 (upper rotating body 3) by operating when the rotating mechanism 2 (upper rotating body 3) is rotating.

The swing reducer 24 is a means for increasing the power (increasing the torque) by decelerating the output (torque) of the swing electric motor 21. The swing reducer 24 is connected to the swing mechanism 2, reduces the output of the swing electric motor 21, and directly drives the swing mechanism 2 to swing. That is, the turning electric motor 21 drives the turning mechanism 2 (upper rotating body 3) to turn via the turning reducer 24.

A current sensor 21s is provided in the power path between the turning motor 21 and the inverter 18B. The current sensor 21s detects the current of the turning motor 21. The current sensor 21s may be a magnetic sensor that uses the magnetoresistance effect, or a direct measurement sensor that uses a shunt resistor or the like, as long as it can detect the current of the turning motor 21.

In addition, since the electric motor 21 for swinging is driven by three-phase (U-phase, V-phase, W-phase) AC power supplied from the inverter 18B, the current sensor 21s detects the current of at least two of the three phases. (i.e., including a plurality of current sensors). Further, the current sensor 21s may be built in the inverter 18B and may detect the current output from the inverter 18B.

The controller 30 is a main control device that performs drive control in the excavator. The controller 30 is composed of an arithmetic processing unit (microcomputer) including, for example, a CPU, ROM, RAM, I/O, etc., and controls various drives by executing various drive control programs stored in the ROM on the CPU. Control is achieved.

The controller 30 converts a pressure signal supplied from the pressure sensor 29 (a signal representing the operating state of the upper rotating structure 3 in the operating device 26) into a speed command C, and controls the drive of the swing electric motor 21. Details will be described later.

Note that the pressure signal (pressure detection value) supplied from the pressure sensor 29 is a signal representing the amount of operation in the operating device 26 (lever 26A) for rotating the rotating mechanism 2 (namely, the upper rotating structure 3).

The controller 30 also controls the operation of the motor-generator 12 (switching between electric (assist) operation and power generation operation), and also controls the operation of the capacitor 19 (see FIG. 3) by controlling the buck-boost converter 100 (see FIG. 3). ) controls charging and discharging. The controller 30 controls the buck-boost converter 100 based on the charging state of the capacitor 19, the operating state of the motor generator 12 (electric (assist) operation or power generation operation), and the operating state of the swing electric motor 21 (power running operation or regenerative operation). Switching control between boost operation and step-down operation is performed, thereby controlling charging and discharging of the capacitor 19.

FIG. 3 is a circuit diagram showing an example of the configuration of power storage system 120.

Power storage system 120 includes a capacitor 19, a buck-boost converter 100, a DC bus 110, and the like.

The DC bus 110 controls the transfer of electric power between the capacitor 19, the motor generator 12, and the swing electric motor 21. The capacitor 19 is provided with a capacitor voltage detection section 112 and a capacitor current detection section 113 that detect the voltage value and current value of the capacitor 19. The capacitor voltage value and capacitor current value detected by the capacitor voltage detection section 112 and the capacitor current detection section 113 are supplied to the controller 30.

The buck-boost converter 100 switches between boosting operation and bucking operation according to the operating states of the motor generator 12 and the swing electric motor 21 so that the DC bus voltage value falls within a certain range. The DC bus 110 is arranged between the inverters 18A, 18B and the buck-boost converter 100, and the capacitor 19, the motor generator 12, and the swing motor 21 exchange power via the DC bus 110.

Switching control between the step-up operation and step-down operation of the buck-boost converter 100 is performed based on the DC bus voltage value detected by the DC bus voltage detection section 111, the capacitor voltage value detected by the capacitor voltage detection section 112, and the capacitor current detection section 113. This is executed by the controller 30 based on the detected capacitor current value.

FIG. 4 is a functional block diagram showing an example of the configuration of the control system (swing control system) of the upper revolving body 3 of the excavator according to the present embodiment. As shown in FIG. 4, the controller 30 includes a swing control section 301 and a monitoring section 302 as functional blocks related to the swing control system.

The swing control unit 301 (an example of a first control unit) controls the current detection value Is of the current sensor 21s, the detection value of the rotational speed (speed detection value) ωs of the resolver 22, and the pressure corresponding to the swing operation of the upper rotating structure 3. The turning electric motor 21 is driven and controlled based on pressure detection values P1s and P2s from the sensor 29 (pressure sensors 29-1 and 29-2). The turning control section 301 includes a command generation section 3011 and a speed/torque feedback control section (speed/torque FB control section) 3012.

Note that the pressure sensors 29-1 and 29-2 correspond to the operation amount of the left turning operation (tilting the lever 26A to the left) and the right turning operation (tilting the lever 26A to the right), respectively. The corresponding pilot pressure detection values (pressure detection values P1s, P2s) are transmitted to the controller 30. That is, the pressure sensors 29-1 and 29-2 are an example of an operation amount detection unit that detects the operation amount (in the left-right direction) of the lever 26A that operates the upper rotating structure 3. Further, the current detection value Is of the current sensor 21s includes a plurality of detection values of the plurality of included current sensors.

The command generation unit 3011 generates a speed command C (for driving and controlling the turning electric motor 21 An example of a generated control command value) is generated. The speed command C is generated, for example, as a command signal indicating a ratio (percentage) to the swing speed (maximum swing speed ωmax) when the lever 26A is fully stroked. The command generation unit 3011 transmits the generated speed command C to the speed/torque FB control unit 3012.

In order to realize the swing speed corresponding to the speed command C, the speed/torque FB control unit 3012 uses the speed detection value ωs of the resolver 22 and the current detection value Is of the current sensor 21s (the corresponding torque of the swing motor 21). Speed feedback control and torque feedback control of the turning electric motor 21 are performed based on the following. Specifically, the speed/torque FB control unit 3012 generates a torque command according to the difference between the turning speed ωc corresponding to the speed command C and the detected speed value ωs. Then, the speed/torque FB control unit 3012 generates a drive signal, such as a PWM signal (Pulse Width Modulation), to drive the inverter 18B according to the difference between the generated torque command and the torque value corresponding to the detected current value Is. Generate a signal. The speed/torque FB control section 3012 transmits a drive signal to the monitoring section 302.

The monitoring unit 302 (an example of a second control unit) uses a gate lock lever signal (an example of information corresponding to the operating state of the gate lock lever 32) from the gate lock lever SW 34 received via a predetermined interface of the controller 30. Based on this, abnormalities related to the operation (swinging operation) of the upper revolving body 3 are monitored. For example, when the gate lock lever signal is OFF, the monitoring unit 302 detects an abnormality regarding the turning operation (abnormality detection processing). Further, for example, when the gate lock lever signal is OFF and an abnormality related to the turning operation is detected, or when a predetermined condition corresponding to the abnormality is satisfied, the monitoring unit 302 changes the operating state of the lever 26A ( Stop control of the upper revolving structure 3 is performed regardless of the operating state of the revolving control unit 301. "Stop control of the revolving upper structure 3" includes both control to stop (decelerate) the revolving upper structure 3 during turning (deceleration control) and control to maintain the stopped state of the revolving upper structure 3 (swing lock control). . That is, when the gate lock lever signal is OFF (that is, when the gate lock lever 32 is in the locked state), the monitoring unit 302 prevents the upper rotating body 3 from rotating regardless of whether or not the lever 26A is operated. . The monitoring unit 302 outputs the drive signal transmitted from the speed/torque FB control unit 3012 to the inverter 18B normally, that is, in a situation where there is no abnormality regarding the turning operation. On the other hand, the monitoring unit 302 realizes stop control of the upper revolving structure 3 by prohibiting (not outputting) the output of the drive signal in a situation where there is an abnormality regarding the turning operation. Details of the processing by the monitoring unit 302 will be described later.

Note that the stop control of the revolving upper structure 3 may be realized by operating the mechanical brake 23. Further, when performing swing lock control, the monitoring unit 302 may prohibit the output of the drive signal, generate the drive signal itself, and perform control to maintain the stopped state (so-called 0-speed control).

[Processing of monitoring unit]
Next, details of the monitoring process in the monitoring unit 302 will be described with reference to FIGS. 5 to 8.

First, FIG. 5 is a flowchart schematically showing an example of the first monitoring process by the monitoring unit 302. The process according to this flowchart is executed, for example, when the excavator is keyed on (when started) or when the excavator is keyed off (when the operation ends). Further, as will be described later with reference to FIG. 7, the process may be executed while the excavator is in operation (from key-on to key-off).

Referring to FIG. 5, in step S102, the monitoring unit 302 determines whether the gate lock lever signal is OFF (that is, whether the gate lock lever 32 is in a locked state). When the gate lock lever signal is OFF, the monitoring unit 302 proceeds to step S104 , and when the gate lock lever signal is not OFF (ON), it skips steps S104 and S106 and ends the current process. do.

In step S104, the monitoring unit 302 performs abnormality detection processing. For example, the monitoring unit 302 determines whether the output value of the monitoring target related to the turning operation is within a normal range, that is, whether it is within a range corresponding to the stopped state of the upper revolving structure 3. The "objects to be monitored regarding the turning operation" include, for example, the current sensor 21s, the resolver 22, the command generation unit 3011, the pressure sensor 29, and the like. Then, when the output value of the monitored object is not within the range corresponding to the stop information of the rotating upper structure 3, the monitoring unit 302 may determine that there is an abnormality regarding the turning operation (abnormality determination). As described above, when the gate lock lever 32 is in the locked state, even if the operator is not operating the excavator or even if the lever 26A is unintentionally touched, the gate lock switching valve 36 will cause the operation device to No pilot pressure is generated on the secondary side of 26. In particular, when the excavator is keyed on (starting up), the gate lock lever 32 is almost always in the locked state, and the excavator is not operated. Therefore, in such a situation, if the output value to be monitored is not within the range corresponding to the stopped state of the upper rotating structure 3, it can be determined that there is an abnormality regarding the swinging operation.

In step S106, the monitoring unit 302 prohibits (cuts off) the output of the drive signal for driving the swing electric motor 21 to the inverter 18B, that is, starts swing lock control, and ends the current process.

In the process shown in FIG. 5, the monitoring unit 302 performs swing lock control regardless of the result of the abnormality detection process, but only when it is determined that there is an abnormality regarding the swing operation as a result of the abnormality detection process. Rotation lock control may also be performed.

In this way, when the gate lock lever signal is OFF, that is, when the gate lock lever 32 is in the locked state, the monitoring unit 302 prevents the upper rotating structure 3 from rotating regardless of whether or not the lever 26A is operated. do. Specifically, when the gate lock lever signal is OFF, the monitoring unit 302 prohibits (cuts off) the output of the drive signal for driving the turning electric motor 21 to the inverter 18B, that is, performs turning lock control. Furthermore, when the gate lock lever signal is OFF, the monitoring unit 302 performs abnormality detection processing for the monitoring target related to the turning operation. As a result, for example, it is possible to detect an abnormality in the turning operation before the operator senses the abnormality in the turning operation that actually occurred, or to prohibit the turning operation in response to the abnormality, so that the upper turning operation can be prevented. The safety of the excavator whose body 3 is electrically driven can be further improved.

Next, FIG. 6 is a flowchart schematically showing another example of the first monitoring process by the monitoring unit 302. Similar to FIG. 5, the process according to this flowchart is executed, for example, when the excavator is keyed on (when started) or when the excavator is keyed off (when the operation ends). Further, as will be described later with reference to FIG. 8, it may be executed while the excavator is in operation (from key-on to key-off).

As described below, the monitoring unit 302 detects abnormalities in the operation of the upper rotating structure 3 based on the gate lock lever signal, the detected speed value ωs, the detected current value Is, the detected pressure values P1s, P2s, and the speed command C. At the same time, the upper revolving body 3 is controlled to stop.

Incidentally, abnormality flags F1 to F4, which will be described later, are initially set to "0" indicating normality.

Referring to FIG. 6, in step S202, the monitoring unit 302 determines whether the gate lock lever signal is OFF (that is, whether the gate lock lever 32 is in a locked state). If the gate lock lever signal is OFF, the monitoring unit 302 proceeds to step S204, and if the gate lock lever signal is not OFF (ON), it skips steps S204 to S224 and ends the current process.

In step S204, the monitoring unit 302 determines whether the detected current value Is is within a range corresponding to the stopped state of the upper rotating structure 3, that is, a range below a predetermined threshold value Isth. If the detected current value Is is not less than or equal to the predetermined threshold Isth, the monitoring unit 302 proceeds to step S206, and if it is less than or equal to the predetermined threshold Isth, the monitoring unit 302 skips step S206 and proceeds to step S208. More specifically, if at least one of the plurality of sensors included in the current sensor 21s does not satisfy the above condition, the monitoring unit 302 proceeds to step S206 and determines whether all sensors included in the current sensor 21s meet the above condition. If satisfied, the process advances to step S208.

Note that the predetermined threshold value Isth is a very high value that corresponds to zero current or so-called zero speed control (for example, control that maintains the rotational speed of the swing electric motor 21 at zero even if an external force such as a gravitational component due to an inclination acts). Set as a small current value.

In step S206, the monitoring unit 302 determines that there is an abnormality in the current sensor 21s (current sensor abnormality), and sets an abnormality flag F1 indicating the presence or absence of an abnormality in the current sensor 21s to "1" indicating an abnormality. As described above, when the gate lock lever 32 is in the locked state, even if the operator is not operating the excavator or even if the lever 26A is unintentionally touched, the operation device is switched off by the action of the gate lock switching valve 36. No pilot pressure is generated on the secondary side of 26. In particular, when the key of the excavator is turned on (starting up), the gate lock lever 32 is almost always in the locked state, and the excavator is not operated. Therefore, in such a situation, if the current detection value Is of the current sensor 21s is not within the range corresponding to the stopped state of the upper rotating structure 3, it can be determined that there is an abnormality in the current sensor 21s.

In step S208, the monitoring unit 302 determines whether the detected speed value ωs is within a range corresponding to the stopped state of the upper rotating body 3, that is, a range below a predetermined threshold value ωsth. If the detected speed value ωs is not less than or equal to the predetermined threshold value ωsth, the monitoring unit 302 proceeds to step S210, and if it is less than or equal to the predetermined threshold value ωsth, the monitoring unit 302 skips step S210 and proceeds to step S212.

Note that the predetermined threshold value ωsth is set as a very small rotational speed value that corresponds to a rotational speed of 0 or so-called 0-speed control.

In step S210, the monitoring unit 302 determines that there is an abnormality in the resolver 22 (resolver abnormality), and sets an abnormality flag F2 indicating the presence or absence of an abnormality in the resolver 22 to "1" indicating an abnormality. This is for the same reason as the abnormality determination of the current sensor 21s in step S206.

In step S212, the monitoring unit 302 determines whether the detected pressure values P1s and P2s are both within a range corresponding to the stopped state of the upper rotating structure 3, that is, a range below a predetermined threshold value Psth. The monitoring unit 302 proceeds to step S214 when either of the pressure detection values P1s and P2s is not below the predetermined threshold Psth, and when both the pressure detection values P1s and P2s are below the predetermined threshold Psth, it skips step S214. , proceed to step S216.

Note that the predetermined threshold value Psth is set as a very small pressure value corresponding to zero pilot pressure (operated amount 0) due to the action of the gate lock switching valve 36.

In step S214, the monitoring unit 302 determines that there is an abnormality in at least one of the pressure sensors 29-1 and 29-2 (pressure sensor abnormality), and indicates whether or not there is an abnormality in the pressure sensors 29-1 and 29-2. The abnormality flag F3 is set to "1" indicating an abnormality. This is for the same reason as the abnormality determination of the current sensor 21s in step S206.

Note that in step S214, it may be determined whether or not there is an abnormality in each of the pressure sensors 29-1 and 29-2, depending on the determination result in step S212.

In step S216, the monitoring unit 302 determines that the abnormality flag F3 is "0" (that is, the pressure sensors 29-1 and 29-2 are normal), and the speed command C indicates that the upper rotating structure 3 is in the stopped state. It is determined whether it is not within the corresponding range, that is, whether it is larger than a predetermined threshold value Cth. If the condition is satisfied, the monitoring unit 302 proceeds to step S218; if the condition is not satisfied, the monitoring unit 302 skips step S218 and proceeds to step S220.

Note that the predetermined threshold value Cth is set as a very small value (percentage) corresponding to a rotational speed of 0 or so-called 0-speed control.

In step S218, the monitoring unit 302 determines that there is an abnormality in the command generation unit 3011 (that is, the software processing that implements the command generation unit 3011) (command generation unit abnormality), and checks whether or not there is an abnormality in the command generation unit 3011. The abnormality flag F4 is set to "1" indicating an abnormality. As described above, when the gate lock lever 32 is in the locked state, even if the operator is not operating the excavator or even if the lever 26A is unintentionally touched, the gate lock switching valve 36 will cause the operation device to No pilot pressure is generated on the secondary side of 26. In particular, when the excavator is keyed on (starting up), the gate lock lever 32 is almost always in the locked state, and the excavator is not operated. Therefore, in this situation, even though the pressure detection values P1s and P2s indicate normal values (corresponding to pilot pressure 0), the speed command C generated by the command generation unit 3011 is If it is not within the range corresponding to the stopped state of the body 3, it can be determined that there is an abnormality in the command generation unit 3011.

In step S220, the monitoring unit 302 determines whether the value of any one of the abnormality flags F1 to F4 is "1", that is, the current sensor 21s, the resolver 22, the pressure sensors 29-1, 29-2, the command It is determined whether there is an abnormality in at least one of the generation units 3011. If the value of any one of the abnormality flags F1 to F4 is "1", the monitoring unit 302 proceeds to step S222, and if the value of all of the abnormality flags F1 to F4 is "0", the process proceeds to steps S222, S224. Skip this and end this process.

In step S222, the monitoring unit 302 prohibits (cuts off) the output of the drive signal for driving the swing electric motor 21 to the inverter 18B, that is, starts swing lock control.

In step S224, the monitoring unit 302 causes a monitor (not shown) in the cabin 10 that is communicably connected to the controller 30 to display a notification (warning) of the occurrence of an abnormality and the abnormal location, and ends the current process. . This allows operators and service personnel to recognize the occurrence of an abnormality and the location of the abnormality, and take appropriate measures such as repair.

Note that the order in which the presence or absence of an abnormality regarding the monitoring target in the process shown in FIG. 6 is determined may be arbitrary. However, the process for determining whether there is an abnormality in the command generation unit 3011 (step S216) needs to be performed after the process for determining whether there is an abnormality in the pressure sensors 29-1, 29-2 (step S212). In addition, in the process shown in FIG. 6, as abnormalities related to the turning operation, the resolver 22 (speed detection value ωs), the current sensor 21s (current detection value Is), the pressure sensors 29-1, 29-2 (pressure detection values P1s, P2s), ) and the command generation unit 3011 (speed command C), the presence or absence of an abnormality is determined for all of the monitoring targets, but it may be determined whether or not there is an abnormality for some of the monitoring targets. That is, the monitoring unit 302 detects an abnormality regarding the turning operation based on the gate lock lever signal and at least one of the detected speed value ωs, the detected current value Is, the detected pressure values P1s and P2s, and the speed command C. It may be. However, if only the gate lock lever signal and the speed command C are used, it is possible to detect an abnormality regarding the turning operation, but it is not possible to specify the location of the abnormality. Further, in the process shown in FIG. 6, both abnormality detection and turning lock control are performed, but it is also possible to perform only abnormality detection, or only to perform turning lock control. In the case of the mode in which only the swing lock control is performed, the monitoring unit 302 performs the swing lock control ( The process of step S222) is performed.

In this way, the monitoring unit 302 detects an abnormality regarding the turning operation based on the gate lock lever signal and at least one of the detected speed value ωs, the detected current value Is, the detected pressure values P1s and P2s, and the speed command C. or perform rotation lock control. Specifically, when the gate lock lever signal indicates the locked state of the gate lock lever 32, the monitoring unit 302 detects the speed detection value ωs, the current detection value Is, the pressure detection values P1s, P2s, and If at least one of the speed commands C is not within the range corresponding to the stopped state of the upper revolving structure 3, it is determined that there is an abnormality regarding the swing operation, or swing lock control is performed. As a result, for example, it is possible to detect an abnormality in the turning operation before the operator senses the abnormality in the turning operation that actually occurred, or to prohibit the turning operation in response to the abnormality, so that the upper turning operation can be prevented. The safety of the excavator whose body 3 is electrically driven can be further improved.

Next, FIG. 7 is a flowchart schematically showing an example of the second monitoring process by the monitoring unit 302. The process according to this flowchart may be executed when the gate lock lever signal changes from ON to OFF while the excavator is operating (between key-on and key-off).

Referring to FIG. 7, in step S302, the monitoring unit 302 determines whether the gate lock lever signal is OFF (that is, whether the gate lock lever 32 is in a locked state). If the gate lock lever signal is OFF, the monitoring unit 302 proceeds to step S304, and if the gate lock lever signal is not OFF (ON), it skips the processes of steps S304 to S310 and ends the current process. do.

In step S304, the monitoring unit 302 determines whether the upper rotating structure 3 is turning. The monitoring unit 302 may use a plurality of the detected speed value ωs, the detected current value Is, the detected pressure values P1s, P2s, and the speed command C to comprehensively determine whether or not the vehicle is turning. Thereby, even if an abnormality occurs in any of the current sensor 21s, the resolver 22, the pressure sensors 29-1, 29-2, and the command generation unit 3011, it is possible to more accurately determine whether or not the vehicle is turning. Furthermore, the monitoring unit 302 may use any one (typically, the detected speed value ωs) to determine whether or not the vehicle is turning. The monitoring unit 302 proceeds to step S306 when the revolving upper structure 3 is turning, and proceeds to step S308 when the revolving upper structure 3 is not turning.

In step S306, the monitoring unit 302 performs a process of urgently stopping the upper revolving structure 3 (emergency stop process).

On the other hand, if it is determined in step S304 that the upper rotating body 3 is not rotating, in steps S308 and S310, the monitoring unit 302 performs abnormality detection processing and rotation locking, as in FIG. 5 (steps S104 and S106). Perform control and end the current process.

In this way, the monitoring unit 302 controls the operation of the swing control unit 301 when the gate lock lever signal changes from ON to OFF, that is, the gate lock lever 32 changes from the unlocked state to the locked state when the upper rotating structure 3 turns. Regardless of this, the revolving upper structure 3 is brought to an emergency stop. Thereby, safety can be further improved.

Next, FIG. 8 is a flowchart schematically showing another example of the second monitoring process by the monitoring unit 302. Similar to FIG. 7, the process according to this flowchart may be executed when the gate lock lever signal changes from ON to OFF while the excavator is in operation (between key-on and key-off).

Referring to FIG. 8, in step S402, the monitoring unit 302 determines whether the gate lock lever signal is OFF (that is, whether the gate lock lever 32 is in a locked state). If the gate lock lever signal is OFF, the monitoring unit 302 proceeds to step S404, and if the gate lock lever signal is not OFF (ON), it skips the processes of steps S404 to S412 and ends the current process. do.

In step S404, the monitoring unit 302 determines whether the upper rotating body 3 is turning. As described above, the monitoring unit 302 uses a plurality of the detected speed value ωs, the detected current value Is, the detected pressure values P1s, P2s, and the speed command C to comprehensively determine whether or not the vehicle is turning. You may do so. Further, as described above, the monitoring unit 302 may use any one (typically, the detected speed value ωs) to determine whether or not the vehicle is turning. The monitoring unit 302 proceeds to step S406 when the revolving upper structure 3 is turning, and proceeds to step S412 when the revolving upper structure 3 is not turning.

In step S406, the monitoring unit 302 blocks (invalidates) the drive signal from the command generation unit 3011, generates a drive signal by itself, and performs control to decelerate the upper revolving body 3 and bring it to an emergency stop (deceleration). control). This is because if the gate lock lever 32 is locked while the upper revolving structure 3 is turning, it can be assumed that the operator sensed some kind of abnormality in the turning operation and operated the gate lock lever 32.

In step S408, the monitoring unit 302 determines whether the upper rotating body 3 has stopped. Similar to step S404, the monitoring unit 302 uses a plurality of the detected speed value ωs, the detected current value Is, the detected pressure values P1s, P2s, and the speed command C to comprehensively determine whether or not the vehicle is turning. Alternatively, any one (typically, the detected speed value ωs) may be used to determine whether or not the vehicle is turning. If the revolving upper structure 3 has stopped, the monitoring unit 302 proceeds to step S410, and if the revolving upper structure 3 has not stopped, it repeats the processes of steps S406 and S408 until it stops.

In step S410, the monitoring unit 302 prohibits (cuts off) the output of the drive signal for driving the swing electric motor 21 to the inverter 18B, that is, starts swing lock control, and ends the current process. Thereby, the turning operation of the upper revolving structure 3 can be quickly prohibited in response to an abnormality regarding the turning operation sensed by the operator.

Note that instead of the process in step S410, the process may proceed to the first monitoring process shown in FIG. Thereby, after confirming that the abnormality detected by the operator has actually occurred, the swing lock control can be started (that is, the swinging operation of the upper revolving structure 3 can be prohibited).

On the other hand, if it is determined in step S404 that the upper rotating body 3 is not rotating, in step S412 the monitoring unit 302 moves to the first monitoring process shown in FIG. 6, and ends the current process. do. As a result, for example, while the excavator is operating, it is possible to determine whether there is an abnormality related to the turning operation each time the operator gets off the cabin 10, increasing the chances of detecting an abnormality and shortening the time lag between abnormality occurrence and detection. Therefore, safety can be further improved.

In this way, the monitoring unit 302 controls the operation of the swing control unit 301 when the gate lock lever signal changes from ON to OFF, that is, the gate lock lever 32 changes from the unlocked state to the locked state when the upper rotating structure 3 turns. Control is performed to decelerate the turning electric motor 21 regardless of this. As a result, when the operator detects some kind of abnormality in the turning operation and operates the gate lock lever 32, the rotating upper rotating body 3 can be brought to an emergency stop, further increasing safety. .

[Other examples of configuration]
Next, other examples of the configuration of the shovel according to this embodiment will be described with reference to FIGS. 9 and 10. In this example, unlike the above-mentioned example (FIGS. 2 and 4), the function (driver function) of the speed/torque FB control section 3012 is built into the inverter 18B, and the function of the monitoring section 302 is external monitoring of the controller 30. It is realized as a device 38. Hereinafter, the same reference numerals will be given to the same configurations as in the example described above, and the explanation will focus on the different parts.

FIG. 9 is a block diagram showing another example of the configuration centered on the drive system of the excavator according to the present embodiment. FIG. 10 is a functional block diagram showing another example of the configuration of the turning control system according to this embodiment.

In FIG. 9, the mechanical power system is shown by a double line, the high pressure hydraulic line is shown by a thick solid line, the pilot line is shown by a broken line, and the electric drive/control system is shown by a thin solid line. Further, the external appearance (side view) of the excavator and the configuration of the power storage system 120 are shown in FIGS. 1 and 3, as in the example described above, and therefore the description thereof will be omitted.

The swing control section 301 (another example of the first control section) includes a command generation section 3011 included in the controller 30 and a speed/torque FB control section 3012 built in the inverter 18B.

The command generation unit 3011 transmits the speed command C to the inverter 18B and also to the monitoring device 38.

The inverter 18B includes an inverter circuit 181B, a communication line 182B, a cutoff section 183B, and a speed/torque FB control section 3012.

The inverter circuit 181B operates based on a drive signal (PWM signal) transmitted from the speed/torque FB control section 3012 through the communication line 182B. Specifically, based on the drive signal, the inverter circuit 181B converts the power supplied from the power storage system 120 into three-phase AC power that drives the swing motor 21, or converts the power supplied from the swing motor 21 into regenerated power. is converted into DC power and supplied to the power storage system 120.

The cutoff section 183B is provided on the communication line 182B that communicably connects the inverter circuit 181B and the speed/torque FB control section 3012, and can switch between connection and cutoff of the communication line 182B. The cutoff unit 183B cuts off the communication line 182B in response to a cutoff signal received from the monitoring device 38 through a predetermined interface of the inverter 18B. The cutoff section 183B is, for example, a mechanical switch or a semiconductor switch (switching element).

The speed/torque FB control unit 3012 is, for example, a driver IC (Integrated Circuit) built into the inverter 18B. The speed/torque FB control unit 3012 receives a speed command C (hereinafter, to distinguish it from the speed command C generated and output by the command generation unit 3011) received from the controller 30 (command generation unit 3011) through a predetermined interface of the inverter 18B. , referred to as "reception speed command Crcv"), a drive signal is generated. That is, the speed/torque FB control unit 3012 adjusts the speed detection value ωs of the resolver 22 and the current detection value Is of the current sensor 21s (corresponding to the swing motor 21 speed feedback control and torque feedback control of the turning electric motor 21 based on the torque of the turning electric motor 21. The speed/torque FB control unit 3012 transmits the generated drive signal to the inverter circuit 181B via the communication line 182B.

The monitoring device 38 (another example of the second control section) is provided separately from the inverter 18B and the controller 30, and includes a current sensor 21s, a resolver 22, pressure sensors 29-1 and 29-2, a gate lock lever SW34, and an inverter 18B. , and the controller 30 in a communicable manner. The monitoring device 38 monitors abnormalities related to the turning operation based on the gate lock lever signal from the gate lock lever SW34. The monitoring device 38 detects, for example, an abnormality related to a turning operation. Further, the monitoring device 38, for example, when detecting an abnormality related to the turning operation, or when a predetermined condition corresponding to the abnormality is satisfied, irrespective of the operating state of the lever 26A (the operating state of the turning control unit 301), Performs stop control of the upper revolving body 3. The monitoring device 38 transmits a cutoff signal to the cutoff unit 183 and cuts off the communication line 182B in a situation where there is an abnormality regarding the swinging operation, thereby realizing stop control of the rotating upper structure 3. Details of the processing by the monitoring device 38 will be described later.

Note that the stop control of the revolving upper structure 3 may be realized by operating the mechanical brake 23. Further, when performing swing lock control, the monitoring device 38 may prohibit the output of the drive signal, generate the drive signal itself, and perform control to maintain the stopped state (so-called 0-speed control). In addition, by omitting the cutoff section 183B and having the monitoring device 38 send a command to the speed/torque FB control section 3012 to prohibit the output of the drive signal, stop control of the upper rotating structure 3 can be realized. Good too.

[Monitoring device processing]
Next, details of the processing in the monitoring device 38 will be described with reference to FIG. 11.

FIG. 11 is a flowchart schematically showing an example of the first monitoring process by the monitoring device 38. The process according to this flowchart is executed, for example, when the excavator is keyed on (when started) or when the excavator is keyed off (when the operation ends). Further, it may be executed while the excavator is in operation (from key-on to key-off) (see FIG. 8, which will be described and cited later).

Similar to the monitoring unit 302 according to the example described above, the monitoring device 38 receives the gate lock lever signal, the detected speed value ωs, the detected current value Is, the detected pressure values P1s and P2s, and the speed command C, as described below. Based on this, an abnormality regarding the operation of the revolving upper structure 3 is detected and the stop control of the revolving upper structure 3 is performed.

In the process shown in FIG. 11, abnormalities related to the turning operation include speed detection value ωs, current detection value Is, pressure detection values P1s and P2s, speed command C, and controller 30 (command generation unit 3011) and inverter 18B (speed - Abnormalities related to all of the communication states with the torque FB control unit 3012) are detected, but an aspect may be adopted in which an abnormality related to at least one is detected. That is, the monitoring device 38 detects an abnormality regarding the turning operation based on the gate lock lever signal and at least one of the detected speed value ωs, the detected current value Is, the detected pressure values P1s, P2s, the speed command C, and the received speed command Crcv. It may be an embodiment in which detection is performed. However, for example, when only the gate lock signal and the speed command C or the received speed command Crcv are used, it is possible to detect an abnormality regarding the turning operation, but it is not possible to specify the abnormal location. Further, in the process shown in FIG. 5, both abnormality detection and swing lock control are performed, but it may be possible to perform only abnormality detection or only perform swing lock control. In the case of a mode in which only swing lock control is performed, the monitoring device 38 controls the swing lock when any one of the conditions for determining that there is an abnormality is satisfied in the processing of steps S504, S508, 312, S516, and S520, which will be described later. Control (processing of step S222) is performed. Additionally, abnormality flags F1 to F5, which will be described later, are initially set to "0" indicating normality.

The processing in steps S502 to S518 in this flowchart is the same as the processing in steps S202 to S218 shown in FIG. 5, so a description thereof will be omitted.

In step S520, the monitoring device 38 determines that the abnormality flags F3 and F4 are "0" (that is, the pressure sensors 29-1 and 29-2 and the command generation unit 3011 are normal), and that the receiving speed command Crcv is at the upper It is determined whether it is not within a range corresponding to the stopped state of the rotating structure 3, that is, whether it is larger than a predetermined threshold value Cth. If the condition is satisfied, the monitoring device 38 proceeds to step S522; if the condition is not satisfied, the monitoring device 38 skips step S522 and proceeds to step S524.

Note that in this step, the monitoring device 38 may determine whether the speed command C and the reception speed command Crcv are the same. When adopting this process, if the speed command C and the receiving speed command CRCv are not the same, the process proceeds to step S522, and if the speed command C and the receiving speed command CRCv are the same, the process skips step S522 and proceeds to step S524. Proceed to.

In step S522, the monitoring device 38 determines that there is an abnormality in the communication state between the controller 30 (command generation unit 3011) and the inverter 18B (speed/torque FB control unit 3012) (communication abnormality), and detects the communication abnormality. The abnormality flag F5 is set to "1" indicating an abnormality. As described above, when the gate lock lever 32 is in the locked state, even if the operator is not operating the excavator or even if the lever 26A is unintentionally touched, the gate lock switching valve 36 will cause the operating device to No pilot pressure is generated on the secondary side of 26. In particular, when the excavator is keyed on (starting up), the gate lock lever 32 is almost always in the locked state, and the excavator is not operated. Therefore, in such a situation, the detected pressure values P1s and P2s show normal values (corresponding to pilot pressure 0), and the speed command C generated by the command generation unit 3011 also shows a normal value. If the received speed command Crcv is not within the range corresponding to the stopped state of the upper revolving structure 3, it can be determined that there is a communication abnormality.

In step S524, the monitoring device 38 determines whether the value of any one of the abnormality flags F1 to F5 is "1", that is, the current sensor 21s, the resolver 22, the pressure sensors 29-1, 29-2, the command The generation unit 3011 determines whether there is an abnormality in at least one of the communication states between the controller 30 and the inverter 18B. If the value of any one of the abnormality flags F1 to F5 is "1", the monitoring device 38 proceeds to step S526, and if the value of all of the abnormality flags F1 to F5 is "0", the process proceeds to steps S526 and S528. Skip this and end this process.

In step S526, the monitoring device 38 transmits a cutoff signal to the inverter 18B (cutoff section 183B), that is, starts swing lock control.

In step S526, the monitoring device 38 causes a monitor (not shown) in the cabin 10 that is communicably connected to display a notification (warning) of the occurrence of an abnormality and the abnormal location, and ends the current process. This allows operators and service personnel to recognize the occurrence of an abnormality and the location of the abnormality, and take appropriate measures such as repair.

As described above, in the configuration according to this example (the configuration in which the command generation unit 3011 is included in the controller 30 and the speed/torque FB control unit 3012 is included in the inverter 18B), the monitoring device 38 receives the gate lock signal and the pressure detection Based on the values P1s and P2s, the speed command C, and the received speed command Crcv, it is possible to detect a communication abnormality between the controller 30 (command generation section 3011) and the inverter 18B (speed/torque FB control section 3012).

Further, the monitoring device 38 performs the second monitoring process, similar to the monitoring unit 302 according to the example described above. The second monitoring process by the monitoring device 38 is shown in FIG. 8 as in the example described above, and therefore the description thereof will be omitted.

Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist described in the claims.

1 Lower traveling body 1A, 1B Traveling hydraulic motor 2 Swivel mechanism 3 Upper rotating body (swivel body)
4 Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 12 Motor generator 13 Reducer 14 Main pump 15 Pilot pump 16 High pressure hydraulic line 17 Control valve 18A Inverter 18B Inverter (drive device)
19 Capacitor 21 Swivel electric motor (electric motor)
21s Current sensor (current detection part)
22 Resolver (speed detection section)
23 Mechanical brake 24 Swing reducer 25 Pilot line 26 Operating device 26A, 26B Lever 26C Pedal 27, 28 Hydraulic line 29, 29-1, 29-2 Pressure sensor (operation amount detection section)
30 Controller 32 Gate lock lever 34 Gate lock lever switch 36 Gate lock switching valve 38 Monitoring device 181B Inverter circuit (drive device)
182B Communication line 183B Cutting section 301 Turning control section (first control section)
302 Monitoring unit (second control unit)
3011 Command generation section 3012 Speed/torque feedback control section

Claims (2)

A rotating body,
An electric motor that drives the rotating body,
When the information regarding the operating state of the gate lock lever indicates the locked state of the gate lock lever , an abnormality regarding the operation of the rotating structure is detected based on the information regarding the operation of the rotating structure, or the rotating structure is Determine whether to stop
shovel. When it is determined that an abnormality related to the operation of the rotating structure is to be detected, detecting an abnormality related to the operation of the rotating structure and identifying an abnormal location based on a plurality of types of information related to the operation of the rotating structure;
The excavator according to claim 1.

Images