Ultra-large hydraulic excavator stair lifting system and safety control strategy

Abstract

The invention discloses a stair lifting system of an ultra-large hydraulic excavator. The stair lifting system comprises a lifting executing mechanism and a stair lifting mechanism, the manual switch controller is used for manually controlling the lifting executing mechanism to work; the automatic control system is used for automatically controlling the lifting executing mechanism to work; a set of complete software control strategy is provided for the safety problem of the current ladder special for pedaling, the safe operation of the ladder special for pedaling is ensured by adopting a multi-redundancy design, the safe operation of the ultra-large hydraulic excavator on software and hardware can be ensured, the safety control strategy design has many interlocking designs and sequential designs, and the safety of the ladder special for pedaling is ensured. The emergency design in case of failure and damage in the system ensures the operation safety, multiple safety design concepts ensure the safe operation of the pedaling ladder, and the man-machine safety in the using process of the pedaling ladder is ensured.

Description

Technical Field

[0001] The invention relates to an ultra-large hydraulic excavator, and in particular to an ultra-large hydraulic excavator stair lifting system and a safety control strategy. Background Art

[0002] Ultra-large hydraulic excavators are large in size, and their cabs are usually located very high above the ground, requiring stairs to get on and off. For the convenience of work and transfer, electric-controlled special boarding stairs are generally used. Electric-controlled special boarding stairs use many solenoid valves and relays, which can only control their up and down movement but cannot guarantee their safety, resulting in safety problems during use and causing injuries to users. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a super-large hydraulic excavator stair lifting system and its safety control strategy. The design can ensure the safe operation of the super-large hydraulic excavator in terms of software and hardware. There are many interlocking designs and sequential designs in the safety control strategy design. There is an emergency design in case of faults and damage in the system to ensure the safety of operation. Multiple safety design concepts ensure the safe operation of the step ladder and the safety of people and machines during the use of the step ladder.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a super-large hydraulic excavator stair lifting system, including: a lifting actuator: used to drive the lifting of the elevator; a manual switch controller: used to manually control the operation of the lifting actuator; an automatic control system: controls the operation of the lifting actuator according to the stair safety control strategy.

[0005] Furthermore, the lifting mechanism includes: a stair locking solenoid valve, a stair unlocking solenoid valve, a stair descending solenoid valve, a stair ascending solenoid valve, a gear rack mechanism, a cylinder, a motor, a manual stop valve, an electronic pump, an accumulator, a check valve, and a fuel tank. The oil outlet of the fuel tank is connected to the oil inlet of the electronic pump through a pipeline, and the oil outlet of the electronic pump is connected to the stair ascending solenoid valve, the manual stop valve, the stair unlocking solenoid valve, the check valve, and the stair unlocking solenoid valve through pipelines. The other end of the check valve is connected to the accumulator through a pipeline, and the pipeline between the check valve and the accumulator is connected to one end of the manual stop valve. The oil return port of the fuel tank is connected to the stair locking solenoid valve and the stair descending solenoid valve through pipelines, respectively. The oil inlet and oil outlet of the motor are connected to the stair descending solenoid valve and the stair ascending solenoid valve through pipelines, respectively. The oil inlet and oil outlet of the fuel cylinder are connected to the stair locking solenoid valve and the stair unlocking solenoid valve through pipelines, respectively. The fuel cylinder is installed at a position where the stairs can be locked through a gear rack mechanism.

[0006] The oil cylinder can also be installed to lock the stairs through the linear guide mechanism, so that when the gear rack mechanism is adjusted, the oil cylinder moves along the linear guide mechanism.

[0007] The staircase is a hydraulic lift staircase, and the motor is a driving motor in the hydraulic lift staircase.

[0008] Furthermore, the pipes connecting the oil cylinder and the stair locking solenoid valve and the stair unlocking solenoid valve are hoses.

[0009] Furthermore, a limit block is provided on the rack in the gear rack mechanism.

[0010] Furthermore, the automatic control system includes: a stair upper limit detection relay, a stair lower limit detection relay, a stair unlocking detection relay, a stair locking detection relay, a stair upward buffer detection relay, a stair downward buffer detection relay, a stair unlocking switch, a stair locking switch, a stair upward switch, a stair downward switch, a safety identification system, and a hydraulic excavator controller. The stair upper limit detection relay, the stair lower limit detection relay, the stair unlocking detection relay, the stair locking detection relay, the stair upward buffer detection relay, the stair downward buffer detection relay, the stair unlocking switch, the stair locking switch, the stair upward switch, the stair downward switch, and the safety identification system are connected to the input end of the hydraulic excavator controller, and the output end of the hydraulic excavator controller is respectively connected to the coils in the stair locking solenoid valve, the stair unlocking solenoid valve, the stair downward solenoid valve, and the stair upward solenoid valve.

[0011] Furthermore, the manual switch controller is a switch control box, and five switches are provided on the switch control box, namely a manual unlocking switch, a manual locking switch, a manual up switch, a manual down switch, and an emergency stop switch. The manual unlocking switch controls the stair unlocking solenoid valve, the manual locking switch controls the stair locking solenoid valve, the manual up switch controls the stair up solenoid valve, the manual down switch controls the stair down solenoid valve, and the emergency stop switch controls both the stair up solenoid valve and the stair down solenoid valve.

[0012] A safety control strategy for a stair lifting system of an ultra-large hydraulic excavator includes: a stair safety control strategy in an automatic mode and a stair safety control strategy in a manual mode.

[0013] Furthermore, the stair safety control strategy in the automatic mode is as follows: (1) When the stairs are not at the upper limit and the stairs are not at the lower limit, that is, the upper limit detection relay of the stairs and the lower limit detection relay of the stairs are both false, the pilot solenoid valve is set to false and the whole machine cannot operate; If it is detected that the stairs are in the unlocked position at this time, that is, the stair unlock detection relay is TRUE, the stair lock solenoid valve is set to false, and pressing the stair lock switch has no effect; if the stair up switch is pressed, the stair up solenoid valve is set to TRUE, and the stair down solenoid valve is set to FALSE, and the stairs go up; if the stair down switch is pressed, the stair up solenoid valve is set to FALSE, and the stair down solenoid valve is set to TRUE, and the stairs go down; If it is detected that the staircase is not in the unlock position at this time, that is, the staircase unlock detection relay is FALSE, press the staircase unlock switch, and the staircase unlock solenoid valve is set to TRUE; (2) When the stairs are at the lower limit, that is, the stair lower limit detection relay is TRUE, the stair lock solenoid valve is set to false, the stair down solenoid valve is set to false, pressing the stair lock switch has no effect, and pressing the stair down switch will prevent the stairs from going down; If the stair unlocking switch is pressed at this time, the stair unlocking solenoid valve is set to true and the stair is unlocked; after the stair is unlocked, the stair up switch is pressed, the stair up solenoid valve is set to true and the stair goes up, and the stair down solenoid valve is set to false; (3) When the stairs are at the upper limit position, that is, the stair upper limit detection relay is true, the stair upward solenoid valve is set to false, and the stairs cannot go up; If the staircase is detected to be in the unlocked position at this time, that is, the staircase unlock detection relay is TRUE, the staircase unlock solenoid valve is set to false, and pressing the unlock switch has no effect. Pressing the staircase down switch sets the staircase down solenoid valve to true, and the staircase goes down; pressing the lock switch sets the staircase lock solenoid valve to TRUE, and the staircase is locked; If the staircase is detected to be in the locked position at this time, that is, the staircase lock detection relay is true, the staircase down solenoid valve is set to false, and the staircase is not allowed to go down; the staircase lock solenoid valve is set to false, and pressing the staircase lock switch has no effect; pressing the staircase unlock switch, the staircase unlock solenoid valve is set to true, and the staircase is unlocked; If the staircase is between the unlocked position and the locked position, that is, the staircase unlock detection relay and the staircase lock detection relay are both false, the staircase down solenoid valve is set to false, and the staircase is not allowed to go down. When the staircase lock switch is pressed, the staircase lock solenoid valve is set to true, and the staircase is locked; when the staircase unlock switch is pressed, the staircase unlock solenoid valve is set to true, and the staircase is unlocked; (4) If the stair descent solenoid valve and stair descent buffer detection relay are true, the stair descent speed is reduced; (5) If the stair ascending solenoid valve and stair ascending buffer detection relay are true, the stair ascending speed is reduced; (6) If at least two of the stair up switch, stair down switch, stair lock switch, and stair unlock switch are pressed at the same time, the stair up solenoid valve, stair down solenoid valve, stair unlock solenoid valve, and stair lock solenoid valve will all be set to FALSE, and the stair will not execute any instructions; (7) If the safety identification system detects pedestrians or obstacles in the designated danger zone while the stairs are descending, the stairs will stop descending; (8) If the safety identification system detects pedestrians or obstacles in the designated danger zone while the stairs are ascending, the stairs will stop ascending.

[0014] Furthermore, the stair safety control strategy in the manual mode is as follows: (1) If you switch to manual mode, the control strategy in automatic control mode will no longer be executed. (2) When the staircase is not at the upper limit and the staircase is not at the lower limit, press the staircase manual up switch to move the staircase up; press the staircase manual down switch to move the staircase down; (3) When the staircase is at the upper limit, press the staircase manual locking switch to lock the staircase. Press the manual unlocking switch to unlock the staircase. Press the staircase manual descending switch to descend the staircase. (4) When the staircase is at the lower limit, press the manual up switch to move the staircase up; (5) After pressing the emergency stop switch, the staircase stops moving immediately; (6) When the cylinder cannot be operated by electronic control, the cylinder position is moved by rotating the rack and pinion mechanism to unlock or lock the stairs; (7) If the electronic pump fails, open the manual shut-off valve and use the accumulator to supply oil.

[0015] The beneficial effects of the present invention are: a complete set of software control strategies is proposed to address the current safety issues of special ladders for pedaling, and multiple redundant designs are used to ensure the safe operation of special ladders for pedaling, which can ensure the safe operation of super-large hydraulic excavators in software and hardware. There are many interlocking designs and sequential designs in the safety control strategy design, and emergency designs when there are faults or damage in the system to ensure the safety of operation. Multiple safety design concepts ensure the safe operation of the ladder and the safety of people and machines during the use of the ladder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 Schematic diagram of the stair safety control strategy in the automatic mode of the present invention; In the figure: 1. Stair upper limit detection relay; 2. Stair lower limit detection relay; 3. Stair unlock detection relay; 4. Stair lock detection relay; 5. Stair upward buffer detection relay; 6. Stair downward buffer detection relay; 7. Stair unlock switch; 8. Stair lock switch; 9. Stair upward switch; 10. Stair downward switch; 11. Safety identification system; 12. Hydraulic excavator controller; 13. Stair lock solenoid valve; 14. Stair unlock solenoid valve; 15. Stair downward solenoid valve; 16. Stair upward solenoid valve; 17. Gear rack mechanism; 18. Cylinder; 19. Motor; 20. Manual stop valve; 21. Electronic pump; 22. Accumulator; 23. Check valve; 24. Manual unlock switch; 25. Manual lock switch; 26. Manual upward switch; 27. Manual downward switch; 28. Emergency stop switch. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0019] like Figure 1 As shown, a super-large hydraulic excavator stair lifting system includes: a lifting actuator: used to drive the lifting of the elevator; a manual switch controller: used to manually control the operation of the lifting actuator; an automatic control system: controls the operation of the lifting actuator according to the stair safety control strategy.

[0020] The lifting mechanism includes: a stair locking solenoid valve 13, a stair unlocking solenoid valve 14, a stair descending solenoid valve 15, a stair ascending solenoid valve 16, a gear rack mechanism 17, an oil cylinder 18, a motor 19, a manual stop valve 20, an electronic pump 21, an accumulator 22, a one-way valve 23, and an oil tank. The oil outlet of the oil tank is connected to the oil inlet of the electronic pump 21 through a pipeline, and the oil outlet of the electronic pump 21 is connected to the stair ascending solenoid valve 16, the manual stop valve 20, the stair unlocking solenoid valve 14, the one-way valve 23, and the stair unlocking solenoid valve 14 through a pipeline. The other end is connected to the accumulator 22 through a pipeline. The pipeline between the one-way valve 23 and the accumulator 22 is connected to one end of the manual stop valve 20. The oil return port of the oil tank is connected to the stair locking solenoid valve 13 and the stair descending solenoid valve 15 through a pipeline. The oil inlet and oil outlet of the motor 19 are connected to the stair descending solenoid valve 15 and the stair ascending solenoid valve 16 through a pipeline. The oil inlet and oil outlet of the oil cylinder 18 are connected to the stair locking solenoid valve 13 and the stair unlocking solenoid valve 14 through a pipeline. The oil cylinder 18 is installed at a position that can lock the stairs through a gear rack mechanism 17.

[0021] The pipelines connecting the oil cylinder 18 with the stair locking solenoid valve 13 and the stair unlocking solenoid valve 14 are hoses, so that the oil cylinder 18 can be moved through the gear rack mechanism 17 .

[0022] Among them, a limit block is provided on the rack in the rack and pinion mechanism, and the limit block is used to block the gear or the cylinder 18 and limit the cylinder 18 to ensure that the use of the safety control strategy for going down the stairs is not affected.

[0023] The automatic control system comprises: a stair upper limit detection relay 1, a stair lower limit detection relay 2, a stair unlocking detection relay 3, a stair locking detection relay 4, a stair upward buffer detection relay 5, a stair downward buffer detection relay 6, a stair unlocking switch 7, a stair locking switch 8, a stair upward switch 9, a stair downward switch 10, a safety identification system 11, and a hydraulic excavator controller 12. The stair upper limit detection relay 1, the stair lower limit detection relay 2, the stair unlocking detection relay 3, the stair locking detection relay 4, the stair upward buffer detection relay 5, the stair downward buffer detection relay 6, the stair unlocking switch 7, the stair locking switch 8, the stair upward switch 9, the stair downward switch 10, and the safety identification system 11 are connected to the input end of the hydraulic excavator controller 12, and the output end of the hydraulic excavator controller 12 is respectively connected to the coils in the stair locking solenoid valve 13, the stair unlocking solenoid valve 14, the stair downward solenoid valve 15, and the stair upward solenoid valve 16.

[0024] The manual switch controller is a switch control box, on which five switches are arranged, namely a manual unlocking switch 24, a manual locking switch 25, a manual up switch 26, a manual down switch 27, and an emergency stop switch 28. The manual unlocking switch 24 controls the stair unlocking solenoid valve 14, the manual locking switch 25 controls the stair locking solenoid valve 13, the manual up switch 26 controls the stair up solenoid valve 16, the manual down switch 27 controls the stair down solenoid valve 15, and the emergency stop switch 28 controls both the stair up solenoid valve 16 and the stair down solenoid valve 15.

[0025] A safety control strategy for a stair lifting system of an ultra-large hydraulic excavator includes: a stair safety control strategy in an automatic mode and a stair safety control strategy in a manual mode.

[0026] like Figure 2 As shown, the stair safety control strategy in automatic mode is as follows: (1) When the stairs are not at the upper limit and the stairs are not at the lower limit, that is, the upper limit detection relay 1 of the stairs and the lower limit detection relay 2 of the stairs are both false, the pilot solenoid valve is set to false and the whole machine cannot operate; If it is detected that the stairs are in the unlocked position at this time, that is, the stair unlock detection relay 3 is TRUE, the stair lock solenoid valve 13 is set to false, and pressing the stair lock switch 8 has no effect; pressing the stair up switch 9, the stair up solenoid valve 16 is set to TRUE, the stair down solenoid valve 15 is set to FALSE, and the stairs go up; pressing the stair down switch 10, the stair up solenoid valve 16 is set to FALSE, the stair down solenoid valve 15 is set to TRUE, and the stairs go down; If it is detected that the staircase is not in the unlocking position at this time, that is, the staircase unlocking detection relay 3 is FALSE, the staircase unlocking switch 7 is pressed, and the staircase unlocking solenoid valve 14 is set to TRUE; (2) When the stairs are at the lower limit, that is, the stair lower limit detection relay 2 is TRUE, the stair locking solenoid valve 13 is set to false, the stair descending solenoid valve 15 is set to false, pressing the stair locking switch 8 has no effect, and pressing the stair descending switch 10 prevents the stairs from descending; If the stair unlocking switch 7 is pressed at this time, the stair unlocking solenoid valve 14 is set to true, and the staircase is unlocked; after the staircase is unlocked, the stair up switch 9 is pressed, the stair up solenoid valve 16 is set to true, and the staircase goes up, and the stair down solenoid valve 15 is set to false; (3) When the stairs are at the upper limit position, that is, the stair upper limit detection relay 1 is true, the stair upward solenoid valve 16 is set to false, and the stairs cannot go up; If it is detected that the stairs are in the unlocked position at this time, that is, the stair unlock detection relay 3 is TRUE, the stair unlock solenoid valve 14 is set to false, and pressing the unlock switch has no effect. Pressing the stair down switch 10 sets the stair down solenoid valve 15 to true, and the stairs go down; pressing the lock switch, the stair lock solenoid valve 13 is set to TRUE, and the stairs are locked; If the staircase is detected to be in the locked position at this time, that is, the staircase lock detection relay 4 is true, the staircase descending solenoid valve 15 is set to false, and the staircase is not allowed to descend; the staircase locking solenoid valve 13 is set to false, and pressing the staircase locking switch 8 has no effect; pressing the staircase unlocking switch 7, the staircase unlocking solenoid valve 14 is set to true, and the staircase is unlocked; If the staircase is between the unlocking position and the locking position, that is, the staircase unlocking detection relay 3 and the staircase locking detection relay 4 are both false, the staircase descending solenoid valve 15 is set to false, and the staircase is not allowed to descend. Press the staircase locking switch 8, the staircase locking solenoid valve 13 is set to true, and the staircase is locked; press the staircase unlocking switch 7, the staircase unlocking solenoid valve 14 is set to true, and the staircase is unlocked; (4) If the stair descent solenoid valve 15 and the stair descent buffer detection relay 6 are true, the stair descent speed is reduced; (5) If the stair ascending solenoid valve 16 and the stair ascending buffer detection relay 5 are true, the stair ascending speed is reduced; (6) If at least two of the stair up switch 9, stair down switch 10, stair lock switch 8, and stair unlock switch 7 are pressed at the same time, the stair up solenoid valve, stair down solenoid valve, stair unlock solenoid valve 14, and stair lock solenoid valve 13 will all be set to FALSE, and the stair will not execute any instructions; (7) If the safety identification system 11 detects pedestrians or obstacles in the designated danger zone during the descent of the stairs, the stairs will stop descending; (8) If the safety identification system 11 detects pedestrians or obstacles in the designated danger zone during the ascending process, the stairs will stop ascending.

[0027] The stair safety control strategy in manual mode is as follows: (1) If you switch to manual mode, the control strategy in automatic control mode will no longer be executed. (2) When the staircase is not at the upper limit and the staircase is not at the lower limit, press the staircase manual up switch 26 to move the staircase up; press the staircase manual down switch 27 to move the staircase down; (3) When the staircase is at the upper limit, press the staircase manual locking switch 25 to lock the staircase. Press the manual unlocking switch 24 to unlock the staircase. Press the staircase manual descending switch 27 to descend the staircase. (4) When the staircase is at the lower limit position, the staircase manual upward switch 26 is pressed to move the staircase upward; (5) After pressing the emergency stop switch 28, the staircase stops moving immediately; (6) When the cylinder 18 cannot be operated by electronic control, the position of the cylinder 18 is moved by rotating the rack and pinion mechanism 17 to unlock or lock the stairs; (7) If the electronic pump 21 fails, the accumulator 22 is used to supply oil by opening the manual stop valve 20.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A super-large hydraulic excavator stair lifting system, characterized in that: include: Lifting actuator: used to drive the elevator to rise and fall; Manual switch controller: used to manually control the operation of the lifting actuator; Automatic control system: used to automatically control the operation of the lifting actuator.

2. The ultra-large hydraulic excavator stair lifting system according to claim 1, characterized in that: The lifting mechanism comprises: a stair locking solenoid valve, a stair unlocking solenoid valve, a stair descending solenoid valve, a stair ascending solenoid valve, a gear rack mechanism, a cylinder, a motor, a manual stop valve, an electronic pump, an accumulator, a check valve, and a fuel tank. The oil outlet of the fuel tank is connected to the oil inlet of the electronic pump through a pipeline, and the oil outlet of the electronic pump is respectively connected to the stair ascending solenoid valve, the manual stop valve, the stair unlocking solenoid valve, the check valve, and the stair unlocking solenoid valve through pipelines. The other end of the check valve is connected to the accumulator through a pipeline, and the pipeline between the check valve and the accumulator is connected to one end of the manual stop valve. The oil return port of the fuel tank is respectively connected to the stair locking solenoid valve and the stair descending solenoid valve through a pipeline, the oil inlet and the oil outlet of the motor are respectively connected to the stair descending solenoid valve and the stair ascending solenoid valve through a pipeline, the oil inlet and the oil outlet of the fuel cylinder are respectively connected to the stair locking solenoid valve and the stair unlocking solenoid valve through a pipeline, and the fuel cylinder is installed at a position where the stairs can be locked through a gear rack mechanism.

3. The ultra-large hydraulic excavator stair lifting system according to claim 2, characterized in that: The pipelines connecting the oil cylinder with the stair locking solenoid valve and the stair unlocking solenoid valve are hoses.

4. The ultra-large hydraulic excavator stair lifting system according to claim 2, characterized in that: A limit block is provided on the rack in the gear rack mechanism.

5. The ultra-large hydraulic excavator stair lifting system according to claim 2, characterized in that: The automatic control system comprises: a stair upper limit detection relay, a stair lower limit detection relay, a stair unlocking detection relay, a stair locking detection relay, a stair upward buffer detection relay, a stair downward buffer detection relay, a stair unlocking switch, a stair locking switch, a stair upward switch, a stair downward switch, a safety identification system, and a hydraulic excavator controller. The stair upper limit detection relay, the stair lower limit detection relay, the stair unlocking detection relay, the stair locking detection relay, the stair upward buffer detection relay, the stair downward buffer detection relay, the stair unlocking switch, the stair locking switch, the stair upward switch, the stair downward switch, and the safety identification system are connected to the input end of the hydraulic excavator controller, and the output end of the hydraulic excavator controller is respectively connected to the coils in the stair locking solenoid valve, the stair unlocking solenoid valve, the stair downward solenoid valve, and the stair upward solenoid valve.

6. The stair lifting system for a super-large hydraulic excavator according to claim 5, characterized in that: The manual switch controller is a switch control box, on which are five switches, namely manual unlocking switch, manual locking switch, manual up switch, manual down switch and emergency stop switch. The manual unlocking switch controls the stair unlocking solenoid valve, the manual locking switch controls the stair locking solenoid valve, the manual up switch controls the stair up solenoid valve, the manual down switch controls the stair down solenoid valve, and the emergency stop switch controls both the stair up solenoid valve and the stair down solenoid valve.

7. The safety control strategy for the stair lifting system of a super-large hydraulic excavator according to claim 5 is characterized by: include: Stair safety control strategy in automatic mode and stair safety control strategy in manual mode.

8. The safety control strategy for the stair lifting system of a super-large hydraulic excavator according to claim 7 is characterized in that: The stair safety control strategy in the automatic mode is as follows: (1) When the stairs are not at the upper limit and the stairs are not at the lower limit, that is, the upper limit detection relay of the stairs and the lower limit detection relay of the stairs are both false, the pilot solenoid valve is set to false and the whole machine cannot operate; If it is detected that the stairs are in the unlocked position at this time, that is, the stair unlock detection relay is TRUE, the stair lock solenoid valve is set to false, and pressing the stair lock switch has no effect; if the stair up switch is pressed, the stair up solenoid valve is set to TRUE, and the stair down solenoid valve is set to FALSE, and the stairs go up; if the stair down switch is pressed, the stair up solenoid valve is set to FALSE, and the stair down solenoid valve is set to TRUE, and the stairs go down; If it is detected that the staircase is not in the unlock position at this time, that is, the staircase unlock detection relay is FALSE, press the staircase unlock switch, and the staircase unlock solenoid valve is set to TRUE; (2) When the stairs are at the lower limit, that is, the stair lower limit detection relay is TRUE, the stair lock solenoid valve is set to false, the stair down solenoid valve is set to false, pressing the stair lock switch has no effect, and pressing the stair down switch will prevent the stairs from going down; If the stair unlocking switch is pressed at this time, the stair unlocking solenoid valve is set to true and the stair is unlocked; after the stair is unlocked, the stair up switch is pressed, the stair up solenoid valve is set to true and the stair goes up, and the stair down solenoid valve is set to false; (3) When the stairs are at the upper limit position, that is, the stair upper limit detection relay is true, the stair upward solenoid valve is set to false, and the stairs cannot go up; If the staircase is detected to be in the unlocked position at this time, that is, the staircase unlock detection relay is TRUE, the staircase unlock solenoid valve is set to false, and pressing the unlock switch has no effect. Pressing the staircase down switch sets the staircase down solenoid valve to true, and the staircase goes down; pressing the lock switch sets the staircase lock solenoid valve to TRUE, and the staircase is locked; If the staircase is detected to be in the locked position at this time, that is, the staircase lock detection relay is true, the staircase down solenoid valve is set to false, and the staircase is not allowed to go down; the staircase lock solenoid valve is set to false, and pressing the staircase lock switch has no effect; pressing the staircase unlock switch, the staircase unlock solenoid valve is set to true, and the staircase is unlocked; If the staircase is between the unlocked position and the locked position, that is, the staircase unlock detection relay and the staircase lock detection relay are both false, the staircase down solenoid valve is set to false, and the staircase is not allowed to go down. When the staircase lock switch is pressed, the staircase lock solenoid valve is set to true, and the staircase is locked; when the staircase unlock switch is pressed, the staircase unlock solenoid valve is set to true, and the staircase is unlocked; (4) If the stair descent solenoid valve and stair descent buffer detection relay are true, the stair descent speed is reduced; (5) If the stair ascending solenoid valve and stair ascending buffer detection relay are true, the stair ascending speed is reduced; (6) If at least two of the stair up switch, stair down switch, stair lock switch, and stair unlock switch are pressed at the same time, the stair up solenoid valve, stair down solenoid valve, stair unlock solenoid valve, and stair lock solenoid valve will all be set to FALSE, and the stair will not execute any instructions; (7) If the safety identification system detects pedestrians or obstacles in the designated danger zone while the stairs are descending, the stairs will stop descending; (8) If the safety identification system detects pedestrians or obstacles in the designated danger zone while the stairs are ascending, the stairs will stop ascending.

9. The safety control strategy for the stair lifting system of a super-large hydraulic excavator according to claim 7 is characterized by: The stair safety control strategy in manual mode is as follows: (1) If you switch to manual mode, the control strategy in automatic control mode will no longer be executed. (2) When the staircase is not at the upper limit and the staircase is not at the lower limit, press the staircase manual up switch to move the staircase up; press the staircase manual down switch to move the staircase down; (3) When the staircase is at the upper limit, press the staircase manual locking switch to lock the staircase. Press the manual unlocking switch to unlock the staircase. Press the staircase manual descending switch to descend the staircase. (4) When the staircase is at the lower limit, press the manual up switch to move the staircase up; (5) After pressing the emergency stop switch, the staircase stops moving immediately; (6) When the cylinder cannot be operated by electronic control, the cylinder position is moved by rotating the rack and pinion mechanism to unlock or lock the stairs; (7) If the electronic pump fails, open the manual shut-off valve and use the accumulator to supply oil.

Images