JP7537460B2 - Crane control method, crane - Google Patents

Description

The present invention relates to a crane and a method for controlling the crane, which performs a regeneration process in which particulates accumulated in a filter through which exhaust gas passes are burned.
Regarding.

The crane is equipped with a diesel engine, a hydraulic pump and a hydraulic actuator. The hydraulic pump is driven by the diesel engine.

The hydraulic oil discharged from the hydraulic pump is supplied to the hydraulic actuator through a control valve. The hydraulic actuator is a hydraulic motor or a hydraulic cylinder. The hydraulic motor drives a winch that winds up a rope connected to a boom or a load.

The crane further includes a DPF (Diesel Particulate Filter). The DPF collects particulate matter from the exhaust gas of the diesel engine. If the amount of particulate matter accumulated in the DPF increases, it can cause problems with the operation of the diesel engine.

In the crane, the diesel engine often operates at a relatively low load. When the diesel engine is under low load, the temperature of the exhaust gas does not rise to the temperature required to combust the particulates.

Therefore, when the amount of particulate matter accumulated in the DPF increases, a regeneration process for the DPF is executed. The regeneration process is a process for burning the particulate matter accumulated in the DPF by controlling the load on the diesel engine to increase.

For example, the crane may be equipped with a load valve that increases the discharge pressure of the hydraulic pump (see, for example, Patent Document 1). By controlling the load valve to the ON state, the load on the diesel engine increases, and the regeneration process is realized.

JP 2017-096033 A

However, in the crane, when the regeneration process is performed by controlling the load application valve, the hydraulic actuator is not controlled in response to the operation of the operating lever.

In other words, once the regeneration process begins, the hydraulic actuator cannot be operated until the regeneration process is completed. Therefore, the time required for the regeneration process may adversely affect the work process of the crane.

On the other hand, when the crane is operating, the hydraulic actuator is not operating for a long period of time. Therefore, if the regeneration process is performed between the operation of the hydraulic actuator, the work efficiency of the crane is improved.

The object of the present invention is to provide a crane control method and a crane that can improve the work efficiency of a crane by performing DPF regeneration processing between hydraulic actuator operations.

A crane control method according to one aspect of the present invention is a method for controlling a crane. The crane includes an engine, a hydraulic pump, an actuator control valve, an unloading valve, a first operation unit, and a second operation unit. The hydraulic pump is driven by the engine. The actuator control valve adjusts the amount of hydraulic oil flowing from the hydraulic pump to the hydraulic actuator. The unloading valve is provided in a path of the hydraulic oil from the hydraulic pump to the actuator control valve. The first operation unit receives an operation to indicate a rotation speed of the engine. The second operation unit receives an operation to indicate a control amount of the actuator control valve. The crane control method is applied when a control mode is selected in the crane that allows operations on the first operation unit and the second operation unit and the execution of a regeneration process that burns particulates accumulated in a filter through which exhaust gas from the engine passes. The crane control method includes a processor executing a rotation speed maintenance control that maintains the rotation speed of the engine at or above a reference speed that is greater than a lower limit of a speed control range. The crane control method further includes the processor executing load retention control when no operation is being performed on the second operation unit under the condition that the rotational speed retention control is being performed. The crane control method further includes the processor executing operation response control when an operation is being performed on the second operation unit under the condition that the rotational speed retention control is being performed. In the rotational speed retention control, the processor controls the rotational speed of the engine using the faster of the command speed corresponding to the operation amount on the first operation unit and the reference speed as a target speed. In the load retention control, the processor holds the actuator control valve in a state in which the supply of the hydraulic oil to the hydraulic actuator is stopped, while holding the unload valve in a default state. In the operation response control, the processor operates the actuator control valve and the unload valve in accordance with the operation amount on the second operation unit.

A crane according to another aspect of the present invention includes the engine, the hydraulic pump, the actuator control valve, the unload valve, the first operation unit, the second operation unit, and the processor. The processor realizes the crane control method.

The present invention makes it possible to provide a crane control method and a crane that can improve the work efficiency of a crane by performing DPF regeneration processing between hydraulic actuator operations.

FIG. 1 is a configuration diagram of a crane according to an embodiment. FIG. 2 is a block diagram showing a configuration of control-related devices in the crane according to the embodiment. FIG. 3 is a block diagram showing the configuration of a hydraulic system in the crane according to the embodiment. FIG. 4 is a block diagram showing the configuration of a main control unit in the crane according to the embodiment. FIG. 5 is a flowchart showing an example of a procedure for controlling a hydraulic system in the crane according to the embodiment.

Below, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention and does not limit the technical scope of the present invention.

[Configuration of crane 10]
The crane 10 according to the embodiment is a work machine that lifts and moves a load.

As shown in FIG. 1, the crane 10 includes a lower carrier 11, an upper rotating body 12, a cab 13, a mast 15, a winch device 16, a counterweight 17, a boom 21, a hook 30, a hoisting rope 31, and a lifting rope 32.

The winch device 16 includes a hoisting winch 161 and a lifting winch 162.

The upper rotating body 12 is a rotating body supported so as to be rotatable by the lower running body 11. The lower running body 11 is a base portion that supports the upper rotating body 12 so as to be rotatable. The upper rotating body 12 is configured integrally with the cab 13.

The mast 15 is supported by the upper rotating body 12 so that it can be raised and lowered. Furthermore, the upper rotating body 12 supports a winch device 16, a counterweight 17, and a boom 21. Note that the lifting winch 162 may be located at the base of the boom 21.

The upper rotating body 12 is rotated by a rotating motor (not shown) provided on the lower running body 11. The rotating motor is a hydraulic motor.

The crane 10 shown in FIG. 1 is a mobile crane. Therefore, the crane 10 further includes a traveling device 14. The traveling device 14 supports the lower traveling body 11 and is capable of traveling. FIG. 1 shows an example in which the traveling device 14 is a crawler-type device.

The cab 13 is a pilot's room. The boom 21 can be raised and lowered around its base, which is connected to the upper rotating body 12. Note that a jib (not shown) may also be rotatably connected to the tip of the boom 21.

The hoisting rope 31 is connected to the mast 15 and the hoisting winch 161 via the upper spreader 18a and the lower spreader 18b. The mast 15 is connected to the boom 21 by a guy line 33. Note that the hoisting winch 161 may also be attached to the mast 15.

In some cases, a gantry (not shown) may be used instead of the mast 15. In some cases, a hoisting winch 161 may be attached to the gantry.

The hoisting winch 161 supports the boom 21 via the hoisting rope 31, the mast 15, and the boom rope 33. The hoisting winch 161 changes the angle of the mast 15 by winding up the hoisting rope 31 or letting out the hoisting rope 31. The angle of the boom 21 changes in response to the change in the angle of the mast 15.

That is, the hoisting winch 161 changes the angle of the boom 21 by winding up the hoisting rope 31 or letting out the hoisting rope 31.

In addition, the winch device 16 may be equipped with a winch that raises and lowers the jib. The boom 21 may also be a telescopic boom.

The hoisting rope 32 is hung on a sheave at the tip of the boom 21. The hoisting rope 32 is connected to a hook 30 and hangs down from the tip of the boom 21.

The hoisting winch 162 raises and lowers the hook 30 by winding up or letting out the hoisting rope 32. The load is suspended from the hook 30.

The counterweight 17 balances the load of the boom 21 and the suspended load.

As shown in FIG. 2, the crane 10 further includes an engine 100, a DPF 101, a hydraulic system 4, a status detection device 40, a control device 8, and a display device 9.

The engine 100 is a diesel engine. The engine 100 is the driving source of the hydraulic system 4. The exhaust gas of the engine 100 passes through the DPF 101 and is discharged from a muffler (not shown). The DPF 14 is a filter that collects particulates in the exhaust gas of the engine 100.

The control device 8 includes an operation device 5, a main control unit 6, and an ECU (Engine Control Unit) 7. The operation device 5 is a device that accepts operations by the operator. The display device 9 is a device that displays information.

For example, the display device 9 includes a panel display device such as a liquid crystal display unit. The operating device 5 and the display device 9 and other human interface devices are provided in the cab 13.

The operating device 5 includes a variable operating device 51, an operating button 52, and an input device 53.

In this embodiment, the variable operation device 51 includes a hoisting operation lever 511, a hanging operation lever 512, and an accelerator grip 513. The hoisting operation lever 511, the hanging operation lever 512, and the accelerator grip 513 are each an example of a variable operation part that is displaced when operated. Displacement of the variable operation part includes, for example, sliding, tilting, and rotating the variable operation part.

The hoisting operation lever 511 accepts operations that command the operation of the hoisting winch 161. The lifting operation lever 512 accepts operations that command the operation of the lifting winch 162.

The accelerator grip 513 receives an operation to specify the rotation speed of the engine 100. The accelerator grip 513 is an example of a first operating unit. An accelerator pedal or an accelerator trimmer may be used instead of the accelerator grip 513.

The variable operation device 51 further includes a displacement detection unit 510. The displacement detection unit 510 detects the amount of displacement of each of the hoisting operation lever 511, the hanging operation lever 512, and the accelerator grip 513, and outputs an operation signal representing the detected amount of displacement. The amount of displacement is the amount of operation of each of the hoisting operation lever 511, the hanging operation lever 512, and the accelerator grip 513.

The operation signal corresponding to the hoisting operation lever 511 or the hanging operation lever 512 indicates the direction of displacement of the multiple hoisting operation levers 511 or the hanging operation lever 512 from the home position and the amount of displacement from the home position.

The operation signal corresponding to the accelerator grip 513 represents the amount of displacement of the accelerator grip 513 from the home position.

The input device 53 accepts information input by the operator. For example, the input device 53 is a touch panel that is integrated with the display device 9. The input device 53 may also be a device that accepts information input by voice operation of the operator.

The main control unit 6 controls the hydraulic system 4. Furthermore, the main control unit 6 outputs control commands for controlling the engine 100 to the ECU 7. The ECU 7 controls the engine 100 in accordance with the control commands.

For example, the main control unit 6, ECU 7, and display device 9 can communicate with each other through a network such as a Controller Area Network (CAN).

The state detection device 40 detects various states of the crane 10. The detection results of the state detection device 40 are transmitted to the main control unit 6 and the ECU 7.

The condition detection device 40 includes a tachometer 401, a load meter 402, a tension sensor 403, an angle meter 404, and a differential pressure meter 405.

The tachometer 401 detects the rotation speed of the engine 100. The main control unit 6 sets a target speed for the engine 100 in response to the operation signal corresponding to the accelerator grip 513. The target speed is output to the ECU 7 as part of the control command.

The ECU 7 controls the engine 100 by feedback control based on the target speed and the detection result of the tachometer 401. In the feedback control, the ECU 7 controls the amount of fuel supplied to the engine 100, etc.

The load meter 402 detects the weight of the load suspended from the hook 30. The tension sensor 403 detects the tension acting on the hoisting rope 31.

The angle meter 404 detects the angle of the boom 21. The differential pressure meter 405 detects the differential pressure of the DPF 101. The differential pressure of the DPF 101 is the difference between the pressure of the exhaust gas in the upstream stage of the DPF 101 and the pressure of the exhaust gas in the downstream stage of the DPF 101. The detection result of the differential pressure meter 405 indicates the amount of accumulated particulate matter in the DPF 14.

As shown in FIG. 3, the hydraulic system 4 includes a hydraulic pump 41, an unloading valve 42, a plurality of actuator control valves 43, a plurality of actuators 44, and a tank 45. Each of the plurality of actuators 44 is a hydraulic actuator.

The hydraulic pump 41 is driven by the engine 100. In this embodiment, the hydraulic pump 41 is a piston pump with a variable tilt angle. The amount of hydraulic oil discharged per rotation of the hydraulic pump 41 changes according to the tilt angle. The tilt angle of the hydraulic pump 41 is controlled by the main control unit 6.

The unloading valve 42 and the actuator control valve 43 are control valves that adjust the flow of hydraulic oil according to the control of the main control unit 6.

The actuator control valve 43 adjusts the amount of hydraulic oil flowing from the hydraulic pump 41 to the actuator 44. The actuator 44 operates with hydraulic oil supplied from the hydraulic pump 41 through the actuator control valve 43.

The actuator 44 is a hydraulic actuator. In this embodiment, the actuator 44 includes a hoisting motor 441 and a hoisting motor 442. Each of the hoisting motor 441 and the hoisting motor 442 is a hydraulic motor.

The hoisting motor 441 drives the hoisting winch 161. The hoisting motor 442 drives the hoisting winch 162.

The actuator 44 also includes a rotation motor (not shown). If the boom 21 is a telescopic boom, the actuator 44 includes a hydraulic cylinder that telescopically extends and retracts the boom 21.

The actuator control valve 43 includes a hoisting control valve 431 and a suspension control valve 432. The hoisting control valve 431 adjusts the amount of hydraulic oil supplied to the hoisting motor 441. The suspension control valve 432 adjusts the amount of hydraulic oil supplied to the suspension motor 442.

The elevation control lever 511 accepts an operation that indicates the control amount of the elevation control valve 431. The MPU 601 controls the elevation control valve 431 according to the operation amount of the elevation control lever 511.

The suspension operation lever 512 accepts an operation that indicates the control amount of the suspension control valve 432. The MPU 601 controls the suspension control valve 432 according to the operation amount of the suspension operation lever 512.

In the following description, the hoisting operation lever 511 and the hoisting operation lever 512 are referred to as operation levers 511, 512. Each of the hoisting operation lever 511 and the hoisting operation lever 512 is an example of the second operation part.

The unloading valve 42 is provided in the hydraulic oil path that runs from the hydraulic pump 41 to the actuator control valve 43. The unloading valve 42 adjusts the balance of the amount of hydraulic oil that flows from the hydraulic pump 41 to the tank 45 and the actuator control valve 43.

The unloading valve 42 increases the amount of hydraulic oil flowing from the hydraulic pump 41 to the tank 45, thereby reducing the load on the hydraulic pump 41.

The main control unit 6 controls the operation of the actuator 44 by controlling the actuator control valve 43.

When a start operation is performed on the operating device 5, the main control unit 6 starts the engine 100 through the ECU 7. Furthermore, the main control unit 6 outputs a control signal to a control target such as the actuator control valve 43 according to the operation on the operating device 5 or the detection results of the various state detection devices 40. Furthermore, the main control unit 6 controls the display device 9.

As shown in FIG. 4, the main control unit 6 includes an MPU (Micro Processing Unit) 601, a RAM (Random Access Memory) 602, a secondary storage device 603, and a signal interface 604.

RAM 602 is a computer-readable volatile storage device. Secondary storage device 603 is a computer-readable non-volatile storage device.

The MPU 601 executes various data processing and control operations by executing computer programs. The MPU 601 is an example of a processor that controls the engine 100 and the hydraulic system 4.

RAM 602 is a volatile memory that temporarily stores the programs executed by MPU 601 and data derived or referenced by MPU 601.

The secondary storage device 603 stores in advance the programs executed by the MPU 601 and the data referenced by the MPU 601. For example, the secondary storage device 603 may be an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory.

The signal interface 604 converts the detection signal of the state detection device 40 into digital data and transmits it to the MPU 601. Furthermore, the signal interface 604 converts the control command output by the MPU 601 into a control signal such as a current signal or a voltage signal, and outputs it to the device to be controlled.

For example, the MPU 601 determines the state of the crane 10 according to the detection result of the state detection device 40. Furthermore, the MPU 601 controls the hydraulic pump 41, the unload valve 42, and the actuator control valve 43 according to the determination result of the state of the crane 10.

In the crane 10, if the amount of particulate matter accumulated in the DPF 101 increases, this will cause problems with the operation of the engine 100.

In addition, in the crane 10, the engine 100 often operates under a relatively low load. When the load on the engine 100 is low, the temperature of the exhaust gas does not rise to a temperature required to combust the particulates.

Therefore, the MPU 601 executes a regeneration process when the amount of particulate matter accumulated in the DPF 101 increases. The regeneration process is a process for burning the particulate matter accumulated in the DPF by controlling the engine 100 to increase its load.

For example, the crane 10 may be equipped with a load application valve (not shown). The load application valve is a valve that increases the discharge pressure of the hydraulic pump 41. By controlling the load application valve to the ON state, the load on the engine 100 increases, and the regeneration process is realized.

However, in the crane 10, when the regeneration process is being performed by controlling the load application valve, control of the actuator 44 in response to the operation of the hoisting operation lever 511 or the lifting operation lever 512 is not performed.

In other words, once the regeneration process starts, the actuator 44 cannot be operated until the regeneration process is completed. Therefore, the time required for the regeneration process may adversely affect the work process of the crane 10.

On the other hand, when the crane 10 is operating, the actuator 44 is not operating for a long period of time. Therefore, if the regeneration process is performed between the operations of the actuator 44, the operating efficiency of the crane 10 is improved.

In the crane 10, the MPU 601 executes the hydraulic system control described below (see FIG. 5). This allows the regeneration process of the DPF 101 to be performed between the operations of the actuator 44.

[Hydraulic system control]
An example of a procedure for controlling the hydraulic system will now be described with reference to the flow chart shown in FIG.

The hydraulic system control procedure is an example of a procedure for implementing the crane control method. The MPU 601 starts the hydraulic system control when the engine 100 starts. The MPU 601 is an example of a processor for implementing the crane control method.

In the following description, S1, S2, ... represent identification symbols of multiple processes in the hydraulic system control. In the hydraulic system control, the MPU 601 first executes the processing of process S1.

<Step S1>
In step S1, the MPU 601 determines whether the control mode selected is the automatic playback mode or the normal mode.

For example, the control mode is selected by operating the mode selection operation button 52.

The automatic regeneration mode is the control mode that allows operation of the accelerator grip 513, the hoisting operation lever 511, and the hoisting operation lever 512, and execution of the regeneration process. On the other hand, the normal mode is the control mode that does not allow execution of the regeneration process.

If the MPU 601 determines that the automatic playback mode is selected, it transitions the process to step S2. On the other hand, if the MPU 601 determines that the normal mode is selected, it transitions the process to step S3.

<Step S2>
In step S2, the MPU 601 judges whether a predetermined playback start condition is met or not.

The regeneration start condition includes a lever no operation condition. The lever no operation condition is a condition in which no operation is performed on the operating levers 511 and 512 while the engine 100 is running.

The regeneration start condition may further include one or both of an engine condition and a filter condition. For example, the regeneration start condition is a logical product of the lever no operation condition, the engine condition, and the filter condition.

The engine condition is that the time elapsed since the start of the engine 100 exceeds a predetermined time. The engine condition is a condition that indicates that the operation of the engine 100 is stable.

The filter condition is that the index value of the amount of particulate matter accumulated in the DPF 101 is within a predetermined reference range. The reference range indicates that a certain amount of particulate matter has accumulated in the DPF 101.

For example, the index value is the detection value of the differential pressure gauge 405. Also, when the detection value of the differential pressure gauge 405 is classified into one of a plurality of candidate ranks, the classified rank may be the index value.

Specifically, when the index value is classified into one of 11 candidate ranks from 0 to 10, the range from 3 to 4 is set as the reference range.

The regeneration start condition may further include a normal condition in which all devices related to the regeneration process are normal. For example, the regeneration start condition is a logical AND of the lever no-operation condition, the engine condition, the filter condition, and the normal condition.

The MPU 601 determines whether the equipment related to the playback process is normal or abnormal based on the detection results of the status detection device 40.

If the MPU 601 determines that the playback start condition is met, it transitions the process to step S4. On the other hand, if the MPU 601 determines that the playback start condition is not met, it transitions the process to step S3.

<Step S3>
In step S3, the MPU 601 executes normal control regarding the hydraulic pump 41, the unload valve 42 and the actuator control valve 43.

During the normal control, the MPU 601 executes accelerator operation response control and lever operation response control in parallel.

The accelerator operation response control is a process that controls the rotation speed of the engine 100 using a command speed that corresponds to the amount of operation on the accelerator grip 513 as a target speed.

In the accelerator operation response control, the MPU 601 sets the command speed corresponding to the amount of operation on the accelerator grip 513 as the target speed. Furthermore, the MPU 601 outputs the target speed to the ECU 7 as part of the control command.

As described above, the ECU 7 controls the engine 100 by feedback control based on the target speed and the detection result of the tachometer 401. That is, the MPU 601 executes control through the ECU 7 to maintain the rotation speed of the engine 100 at the target speed.

The lever operation response control includes control for operating the actuator control valve 43 and the unloading valve 42 in response to the amount of operation of the operating levers 511, 512. Furthermore, the lever operation response control includes control for changing the tilt angle of the hydraulic pump 41 in response to the amount of operation of the operating levers 511, 512.

Specifically, the MPU 601 controls the unload valve 42 and the elevation control valve 431 so that the amount of hydraulic oil supplied to the elevation motor 441 increases as the amount of operation of the elevation control lever 511 increases.

Similarly, the MPU 601 controls the unload valve 42 and the suspension control valve 432 so that the amount of hydraulic oil supplied to the suspension motor 442 increases as the amount of operation of the suspension operation lever 512 increases.

The MPU 601 transitions the process to step S1 while executing the normal control. As a result, the MPU 601 continues the normal control if the control mode is the normal mode or if the playback start condition is not satisfied.

<Step S4>
In step S4, the MPU 601 displays a predetermined playback control message on the display device 9. The playback control message indicates that the playback process is to be executed.

After executing step S4, the MPU 601 transitions to step S5.

<Step S5>
In step S5, the MPU 601 executes rotation speed maintenance control. The rotation speed maintenance control is a control for maintaining the rotation speed of the engine 100 at or above a reference speed that is higher than an idling speed. The idling speed is the lower limit speed of the speed control range of the engine 100.

In the rotation speed maintenance control, the MPU 601 maintains the rotation speed of the engine 100 at or above the reference speed, regardless of whether the accelerator grip 513 is operated or not. For example, the reference speed is a speed that is 70% or more of the rated speed of the engine 100.

The reference speed is set appropriately according to the specifications of the engine 100 and other devices so that the exhaust gas temperature is suitable for the generation process. Therefore, the reference speed may be set to a speed of about 50% to 70% of the rated speed of the engine 100.

In step S5, the MPU 601 controls the rotation speed of the engine 100 by setting the higher of the command speed corresponding to the operation amount of the accelerator grip 513 and the reference speed as the target speed.
The MPU 601, while maintaining the rotation speed of the engine 100 at or above the reference speed through the ECU 7, shifts the process to step S6.

<Step S6>
In step S6, the MPU 601 executes load holding control. The load holding control is control for holding the actuator control valve 43 in a supply stop state and holding the unloading valve 42 in a default state. Hereinafter, the default state is referred to as a loaded state.

The supply stop state is a state in which the actuator control valve 43 stops the supply of the hydraulic oil to the actuator 44. By holding the unload valve 42 in the loaded state, a predetermined load is applied to the hydraulic pump 41. As a result, a load is applied to the engine 100, and the temperature of the exhaust gas is maintained at a high temperature.

For example, if the opening area of the port of the unloading valve 42 is designed to place an appropriate load on the hydraulic pump 41, the loaded state may be a fully open state of the unloading valve 42.

When the load-applied state is a fully open state of the unloading valve 42, even if the actuator 44 includes a hydraulic cylinder, unintentional extension of the hydraulic cylinder is avoided.

Furthermore, in the load holding control, the MPU 601 holds the tilt angle of the hydraulic pump 41 at a reference tilt angle. In this embodiment, the reference tilt angle is an angle greater than the lower limit of the tilt control range of the hydraulic pump 41.

For example, the reference tilt angle is the upper limit of the tilt control range. By maintaining the tilt angle of the hydraulic pump 41 at the reference tilt angle, an even greater load is applied to the hydraulic pump 41. As a result, an even greater load is applied to the engine 100, and the temperature of the exhaust gas is maintained at an even higher temperature.

The reference tilt angle is set appropriately according to the specifications of the engine 100 and other devices so that the exhaust gas temperature is suitable for the generation process. Therefore, the reference tilt angle may be set to the lower limit of the tilt control range.

The control of step S6 is executed when the operating levers 511 and 512 are not operated while the rotation speed maintenance control of step S5 is being executed. While executing the control of step S6, the MPU 601 shifts the process to step S7.

<Step S7>
In step S7, the MPU 601 judges whether the reproduction end condition is satisfied or not.

The playback end condition includes a first end condition. The first end condition is a condition in which the normal mode is selected as the control mode.

The playback termination condition may further include one or more of a second termination condition, a third termination condition, a fourth termination condition, and a fifth termination condition.

The second termination condition is that the index value for the amount of accumulated particulate matter in the DPF 101 falls below the reference range.

The third termination condition is that the index value of the amount of accumulated particulate matter in the DPF 101 is within the reference range and the duration of regeneration has reached a predetermined upper limit time.

The regeneration duration is the time during which both the rotation speed maintenance control and the load maintenance control are continuously executed. The regeneration duration is reset when the operating levers 511, 512 are operated.

The fourth termination condition is that the index value for the amount of accumulated particulate matter in the DPF 101 exceeds the reference range.

The fifth termination condition is that an abnormality is detected in any of the devices related to the playback process.

For example, the playback end condition is the logical sum of the first end condition, the second end condition, the third end condition, the fourth end condition, and the fifth end condition.

If the MPU 601 determines that the playback end condition is met, it transitions the process to step S8. On the other hand, if the MPU 601 determines that the playback end condition is not met, it transitions the process to step S9.

<Step S8>
In step S8, the MPU 601 erases the playback control message displayed on the display device 9 in step S4.

If it is determined that the third, fourth or fifth termination condition is satisfied, the MPU 601 causes the display device 9 to display an error message corresponding to the satisfied condition in step S8.

When it is determined that the fourth termination condition is satisfied, the MPU 601 causes the display device 9 to display a message prompting the user to execute the manual regeneration process. The manual regeneration process is the regeneration process in a state in which operation of the operating levers 511 and 512 is not accepted.

After executing step S8, the MPU 601 transitions the process to step S3. This causes the normal control to be executed.

<Step S9>
In step S9, the MPU 601 selects the control content to be subsequently executed depending on whether the control levers 511, 512 are being operated or not.

If no operation is performed on the operating levers 511 and 512, the MPU 601 shifts the process to step S5. This causes the rotation speed maintenance control and the load maintenance control to be executed.

On the other hand, if the operating levers 511 and 512 are being operated, the MPU 601 transitions the process to step S10.

<Step S10>
In step S10, the MPU 601 executes the rotation speed maintenance control in the same manner as in step S5.

The MPU 601 transitions the process to step S11 while executing the control of step S10.

<Step S11>
In step S11, the MPU 601 executes the lever operation responsive control in the same manner as in step S3. Note that when the lever operation responsive control is executed, the load holding control is not executed.

However, when switching from the load holding control to the lever operation responsive control, the MPU 601 first controls the unloading valve 42 to a fully open state. That is, the MPU 601 controls the unloading valve 42 to a fully open state, and then executes the switching from the load holding control to the lever operation responsive control.

The MPU 601 transitions the process to step S7 while executing the control of step S11.

As described above, when the automatic regeneration mode is selected in the crane 10, the MPU 601 executes the load retention control or the lever operation response control while executing the rotational speed retention control (see steps S2 and S5 to S11).

In this embodiment, when the regeneration start condition is met while the engine 100 is operating, the MPU 601 starts the rotation speed maintenance control and the load maintenance control (see steps S2, S5, and S6).

In addition, the MPU 601 executes the rotation speed maintenance control from when the playback start condition is met until the playback end condition is met, regardless of whether the operating levers 511, 512 are operated (see steps S2 to S11).

The MPU 601 executes the load retention control when the operating levers 511, 512 are not being operated while the rotation speed retention control is being executed (see steps S2 and S5 to S6).

On the other hand, the MPU 601 executes the lever operation response control when the operating levers 511, 512 are operated while the rotation speed maintenance control is being executed (see steps S9 to S11).

In other words, after starting the load holding control in step S6, the MPU 601 switches the control of the unloading valve 42 and the actuator control valve 43 from one of two types of control to the other depending on the operation state of the operating levers 511, 512 (see steps S5 to S7 and steps S9 to S11).

The two types of control are the load holding control and the operation response control. In this embodiment, the load holding control and the operation response control also include control of the tilt angle of the hydraulic pump 41.

The processes of steps S5 and S6 in the hydraulic system control are an example of the regeneration process. By executing the hydraulic system control, the regeneration process is performed between the operations of the actuator 44 in step S11. As a result, the work efficiency of the crane 10 is improved.

In addition, even if the control over the unload valve 42 and the actuator control valve 43 switches from the load holding control to the lever operation response control, the rotational speed holding control continues.

Therefore, the particulate matter that has accumulated in the DPF 101 is prevented from adhering to the DPF 101 due to a sudden drop in the temperature of the exhaust gas.

Even if the load holding control is switched to the lever operation response control, the regeneration process may continue depending on the operation status of the operating levers 511 and 512.

[Application example]
In step S4 of the hydraulic system control, the MPU 601 may execute one or both of a standby process and a confirmation process.

The standby process is a process of waiting until a preset time has elapsed. During the standby process, the MPU 601 displays a message on the display device 9 that counts down the standby time.

By executing the standby process, the operator can make various preparations before the playback process begins.

The confirmation process is a process that selects whether to proceed to step S3 or step S5 depending on the confirmation operation performed on the operation device 5.

For example, in the confirmation process, the MPU 601 shifts the process to step S5 when an authorized operation on the operation device 5 is detected. Alternatively, the MPU 601 may shift the process to step S5 when an unauthorized operation on the operation device 5 is not detected within a predetermined time.

For example, the permitted operation and the disallowed operation are operations on the operation button 52 or the input device 53, respectively.

In addition, the MPU 601 may shift the process to step S3 when the unauthorized operation is detected in the confirmation process. Alternatively, the MPU 601 may shift the process to step S3 when the permitted operation is not detected within a predetermined time.

By executing the confirmation process, it is possible to cancel the regeneration process depending on the convenience of the work performed by the crane 10.

4: Hydraulic system 5: Operating device 6: Main control unit 7: ECU
8: Control device 10: Crane 21: Boom 30: Hook 31: Hoisting rope 32: Suspension rope 40: State detection device 51: Variable operation device 511: Hoisting operation lever (second operation unit)
512: Lifting operation lever (second operation part)
513: Accelerator grip (first operating part)
601: MPU (processor)

Claims (5)

1. A crane control method, comprising:
The crane,
The engine,
a hydraulic pump driven by the engine;
an actuator control valve for adjusting the amount of hydraulic oil flowing from the hydraulic pump to the hydraulic actuator;
an unloading valve provided in a path of the hydraulic oil from the hydraulic pump to the actuator control valve;
A first operation unit that receives an operation to specify a rotation speed of the engine;
a second operation unit that receives an operation to instruct a control amount of the actuator control valve,
In the crane, when a control mode that allows operation of the first operation unit and the second operation unit and execution of a regeneration process that burns particulates accumulated in a filter through which exhaust gas of the engine passes is selected,
A processor executes a rotation speed maintenance control for maintaining the rotation speed of the engine at or above a reference speed that is higher than a lower limit of a speed control range;
The processor executes a load maintenance control when no operation is performed on the second operation unit under a situation in which the rotation speed maintenance control is being executed;
The processor executes an operation response control when an operation is performed on the second operation unit under a situation in which the rotation speed maintenance control is being executed,
the processor controls the rotation speed of the engine in the rotation speed maintenance control by setting a higher speed out of an instruction speed corresponding to an operation amount of the first operation unit and the reference speed as a target speed;
In the load retention control, the processor maintains the actuator control valve in a state in which the supply of the hydraulic oil to the hydraulic actuator is stopped, while maintaining the unload valve in a default state;
A crane control method in which the processor, in the operation-responsive control, operates the actuator control valve and the unloading valve in accordance with the amount of operation to the second operation unit. When the hydraulic pump is a piston pump,
The processor holds the tilt angle of the hydraulic pump at a reference tilt angle that is greater than a lower limit of a tilt control range in the load holding control,
The crane control method according to claim 1 , further comprising: controlling a tilt angle of the hydraulic pump in response to an amount of operation of the second operation unit in the operation responsive control. the processor starts the rotation speed holding control and the load holding control when a regeneration start condition is satisfied, the regeneration start condition including a condition that no operation is performed on the second operation unit while the engine is running;
The crane control method according to claim 1 or claim 2, further comprising: after starting the load holding control, switching control of the unload valve and the actuator control valve from one of the load holding control and the operation responsive control to the other depending on the state of operation of the second operation unit. The crane control method according to claim 3, wherein the regeneration start condition further includes one or both of a condition regarding the elapsed time since the start of the engine and a condition regarding the amount of accumulated particulate matter in the filter. The engine,
a hydraulic pump driven by the engine;
an actuator control valve for adjusting the amount of hydraulic oil flowing from the hydraulic pump to the hydraulic actuator;
an unloading valve provided in a path of the hydraulic oil from the hydraulic pump to the actuator control valve;
A first operation unit that receives an operation to specify a rotation speed of the engine;
a second operation unit that receives an operation for instructing a control amount of the actuator control valve;
A control device,
When a control mode that allows operation of the first operating unit and the second operating unit and execution of a regeneration process that burns particulates accumulated in a filter through which exhaust gas of the engine passes is selected,
the control device executes a rotation speed maintenance control for maintaining the rotation speed of the engine at or above a reference speed that is higher than a lower limit of a speed control range;
Furthermore, the control device executes a load holding control when no operation is performed on the second operation unit under a situation in which the rotation speed holding control is being executed,
Furthermore, the control device executes an operation response control when an operation is performed on the second operation unit while the rotation speed maintenance control is being executed,
the control device controls the rotation speed of the engine using a higher speed of an instruction speed corresponding to an operation amount of the first operation unit and the reference speed as a target speed in the rotation speed maintenance control,
Furthermore, in the load retention control, the control device maintains the actuator control valve in a state in which the supply of the hydraulic oil to the hydraulic actuator is stopped, while maintaining the unloading valve in a default state,
Furthermore, the control device, in the operation responsive control, operates the actuator control valve and the unloading valve in accordance with the amount of operation to the second operation unit .

Images