Heavy-load mechanical arm potential energy recovery system and control method

Abstract

The invention discloses a heavy-load mechanical arm potential energy recovery system and a control method, and particularly relates to the technical field of hydraulic excavators, the heavy-load mechanical arm potential energy recovery system comprises a hydraulic pump, a three-position four-way electromagnetic valve, a three-cavity hydraulic cylinder, a first pressure sensor, a second pressure sensor, a first proportional valve, a second proportional valve, a third proportional valve, an energy accumulator, a range finder and a controller; the hydraulic pump is connected with the three-position four-way electromagnetic valve, a first pressure sensor is arranged on a pipeline where one outlet of the three-position four-way electromagnetic valve is communicated with a rod cavity, the other outlet of the three-position four-way electromagnetic valve is connected with a rodless cavity, the first proportional valve and the second proportional valve are both connected with the energy storage cavity, and a second pressure sensor is arranged on a pipeline where the first proportional valve is connected with the energy accumulator. The second proportional valve is connected and communicated with the oil tank, an oil inlet of the third proportional valve is connected with the hydraulic pump, an oil outlet of the third proportional valve is connected with the energy accumulator, and a range finder is installed on the bucket. The working state can be automatically switched, the misjudgment rate is reduced, the controllability of the whole machine is improved, and the potential energy recovery rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic excavators, and in particular to a heavy-load mechanical arm potential energy recovery system and a control method. Background Art

[0002] Hydraulic excavators have the characteristics of high working efficiency, good adaptability to working conditions, and a wide range of applications. However, the load inertia of the actuator of the mechanical arm of the hydraulic excavator is large, and there is serious energy loss in the process of frequently lifting and lowering materials. At present, the most efficient and simple way to recover the energy of the excavator mechanical arm is to use an accumulator as an energy storage element and replace the original two-chamber hydraulic cylinder with a three-chamber hydraulic cylinder to recover the potential energy of the excavator mechanical arm. However, when the special working condition of supporting the vehicle is achieved by stretching and adjusting the position and posture of the mechanical arm, the accumulator connected to the energy storage chamber is always in a pressurized state, so there is a large resistance in the process of descending the mechanical arm, which often causes the rod chamber pressure of the three-chamber hydraulic cylinder to reach the overflow pressure value of the system, causing the excavator to lose its original working ability and seriously affecting the controllability of the whole machine. Summary of the invention

[0003] The purpose of the present invention is to provide a heavy-loaded robotic arm potential energy recovery system and control method to solve the problems existing in the above-mentioned prior art, which can automatically switch working states, reduce the misjudgment rate, improve the controllability of the whole machine, and improve the potential energy recovery rate.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a potential energy recovery system for a heavy-duty mechanical arm, comprising an oil tank, a hydraulic pump, a power element, a three-position four-way solenoid valve, a three-chamber hydraulic cylinder, a first pressure sensor, a second pressure sensor, a first proportional valve, a second proportional valve, a third proportional valve, an accumulator, a rangefinder and a controller; the power element is transmission-connected to the hydraulic pump, the oil inlet of the hydraulic pump is connected and communicated with the oil tank, the oil outlet of the hydraulic pump is connected and communicated with the oil inlet of the three-position four-way solenoid valve, the first oil outlet of the three-position four-way solenoid valve is connected and communicated with the rod chamber of the three-chamber hydraulic cylinder, and the first pressure sensor is arranged on the pipeline connecting the first oil outlet of the three-position four-way solenoid valve and the rod chamber of the three-chamber hydraulic cylinder, and the second oil outlet of the three-position four-way solenoid valve is connected to the rodless chamber of the three-chamber hydraulic cylinder and are connected, the oil inlet of the first proportional valve and the oil inlet of the second proportional valve are both connected and connected to the energy storage chamber of the three-chamber hydraulic cylinder, the oil outlet of the first proportional valve is connected and connected to the accumulator, the second pressure sensor is arranged on the pipeline connecting the oil outlet of the first proportional valve and the accumulator, the oil outlet of the second proportional valve is connected and connected to the oil tank, the accumulator is connected and connected to the oil outlet of the third proportional valve, the oil inlet of the third proportional valve is connected and connected to the hydraulic pump, the rangefinder is fixedly installed on the bucket, the rangefinder is used to detect the distance between the bucket and the ground, the first pressure sensor, the second pressure sensor, the first proportional valve, the second proportional valve, the third proportional valve and the rangefinder are all connected to the controller signal.

[0006] Preferably, a flow direction check valve is provided on the pipeline connecting the oil outlet of the third proportional valve and the accumulator.

[0007] Preferably, it also includes a camera, which is fixedly mounted on the bucket and is connected to the controller signal.

[0008] Preferably, it further includes an overflow valve, the accumulator is connected and communicated with the oil tank, and the overflow valve is arranged on the pipeline communicating between the accumulator and the oil tank.

[0009] The present invention also provides a control method using the heavy-duty mechanical arm potential energy recovery system, including a mechanical arm descending condition and a mechanical arm ascending condition;

[0010] Robot arm descending condition:

[0011] According to the pressure information of the rod chamber of the three-chamber hydraulic cylinder monitored by the first pressure sensor and the distance information from the bucket to the excavation surface collected by the rangefinder received by the controller, it is jointly determined whether the boom is in a working condition requiring the boom to be lowered; only when the pressure signal and the distance signal simultaneously meet the lowering working condition, the controller obtains the working condition information that the mechanical arm is in the lowering of the mechanical arm; the controller controls the closing of the first proportional valve to cut off the passage between the energy storage chamber of the three-chamber hydraulic cylinder and the accumulator, and at the same time opens the second proportional valve to connect the passage between the energy storage chamber of the three-chamber hydraulic cylinder and the oil tank, and unloads the energy storage chamber of the three-chamber hydraulic cylinder, so that the mechanical arm can be lowered smoothly;

[0012] The robot arm descends and then rises again:

[0013] After the excavator is in the condition of lowering the mechanical arm, the controller continues to collect and analyze the pressure signal and the distance signal. When the controller determines that the preset conditions for the ascent of the mechanical arm are met, the controller opens the first proportional valve to connect the energy storage chamber of the three-chamber hydraulic cylinder with the passage of the accumulator, and at the same time closes the second proportional valve to cut off the passage between the energy storage chamber of the three-chamber hydraulic cylinder and the oil tank. The hydraulic oil in the accumulator enters the energy storage chamber of the three-chamber hydraulic cylinder through the first proportional valve to achieve the ascent and merging of the mechanical arm. When the pressure monitored by the second pressure sensor received by the controller is insufficient, the controller controls the opening of the third proportional valve to achieve pressure closed-loop control to ensure that the excavator can maintain normal operation in the energy recovery mode.

[0014] Compared with the prior art, the present invention has achieved the following technical effects:

[0015] The present invention provides a heavy-duty mechanical arm potential energy recovery system and a control method. The working state of an excavator can be measured in real time through a first pressure sensor and a rangefinder, and the collected signal is transmitted to a controller. The controller analyzes and judges, thereby realizing automatic identification of the working condition of the excavator. Then, the controller completes automatic switching of a multi-mode control system by controlling the opening of a first proportional valve and a second proportional valve, effectively avoiding misjudgment caused by sudden signal changes. The controller can accurately identify the working state of the excavator and automatically control the switching of working modes to ensure the timeliness and smoothness of the switching. In the boom lifting stage, the signal is collected by the second pressure sensor and transmitted to the controller, a pressure closed-loop control strategy is set, and the opening of the third proportional valve is controlled by the controller output signal to realize a pressure closed-loop, thereby ensuring the pressure stability of the entire system loop. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is the basic principle diagram of the potential energy recovery system of the heavy-duty robotic arm.

[0018] In the figure: 1-hydraulic pump; 2-power element; 3-three-position four-way solenoid valve; 4-three-chamber hydraulic cylinder; 5-first proportional valve; 6-accumulator; 7-second proportional valve; 8-third proportional valve; 9-overflow valve; 10-oil tank; 11-first pressure sensor; 12-second pressure sensor; 13-rangefinder; 14-camera; 15-check valve; 16-controller; 17-operating handle. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The purpose of the present invention is to provide a heavy-loaded robotic arm potential energy recovery system and control method to solve the problems existing in the above-mentioned prior art, which can automatically switch working states, reduce the misjudgment rate, improve the controllability of the whole machine, and improve the potential energy recovery rate.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1

[0023] This embodiment provides a heavy-duty mechanical arm potential energy recovery system. Figure 1As shown, it includes an oil tank 10, a hydraulic pump 1, a power element 2, a three-position four-way solenoid valve 3, a three-chamber hydraulic cylinder 4, a first pressure sensor 11, a second pressure sensor 12, a first proportional valve 5, a second proportional valve 7, a third proportional valve 8, an accumulator 6, a rangefinder 13 and a controller 16; the power element 2 is transmission-connected to the hydraulic pump 1, the oil inlet of the hydraulic pump 1 is connected and communicated with the oil tank 10, the oil outlet of the hydraulic pump 1 is connected and communicated with the oil inlet of the three-position four-way solenoid valve 3, the first oil outlet of the three-position four-way solenoid valve 3 is connected and communicated with the rod chamber of the three-chamber hydraulic cylinder 4, and the first pressure sensor 11 is arranged on the pipeline connecting the first oil outlet of the three-position four-way solenoid valve 3 with the rod chamber of the three-chamber hydraulic cylinder 4, and the second oil outlet of the three-position four-way solenoid valve 3 is connected to the rodless The oil inlet of the first proportional valve 5 and the oil inlet of the second proportional valve 7 are both connected and communicated with the energy storage chamber of the three-chamber hydraulic cylinder 4, the oil outlet of the first proportional valve 5 is connected and communicated with the accumulator 6, a second pressure sensor 12 is arranged on the pipeline connecting the oil outlet of the first proportional valve 5 and the accumulator 6, the oil outlet of the second proportional valve 7 is connected and communicated with the oil tank 10, the accumulator 6 is connected and communicated with the oil outlet of the third proportional valve 8, the oil inlet of the third proportional valve 8 is connected and communicated with the hydraulic pump 1, a distance meter 13 is fixedly installed on the bucket, the distance meter 13 is used to detect the distance between the bucket and the ground, the first pressure sensor 11, the second pressure sensor 12, the first proportional valve 5, the second proportional valve 7, the third proportional valve 8 and the distance meter 13 are all connected with the controller 16 signal. The pressure of the rod chamber of the three-chamber hydraulic cylinder 4 is collected by the first pressure sensor 11 as the first signal for multi-mode control judgment. The rangefinder 13 is set to collect the distance from the bucket to the excavation surface in real time as the second signal for multi-mode control judgment. The pressure signal and the distance signal are transmitted to the controller 16. The controller 16 analyzes and judges the two signals to realize automatic identification of the excavator working condition. Then the controller 16 completes the automatic switching of the multi-mode control system by controlling the opening of the first proportional valve 5 and the second proportional valve 7. Only when the two signals meet the preset conditions at the same time can it be judged that the excavator has entered the special working mode of supporting the ground. When the controller After the controller 16 determines that the signal meets the preset conditions for boom lifting, the controller 16 switches to the original energy recovery mode. The two signals ensure that the controller 16 can make a correct judgment to avoid misjudgment of the controller 16 due to a sudden change of a certain signal. The controller 16 can accurately identify the working state of the excavator and automatically control the switching of working modes to ensure the timeliness and smoothness of the switching; in the boom lifting stage, the signal collected by the second pressure sensor 12 is transmitted to the controller 16, and a pressure closed-loop control strategy is set. The controller 16 outputs a signal to control the opening of the third proportional valve 8 to realize a pressure closed-loop, thereby ensuring the pressure stability of the entire system loop.Preferably, the controller 16 is connected to the control handle signal, and the operator can actively input the signal to the controller 16 through the control handle to complete the heavy-load impact action. The controller 16 analyzes the distance signal of the rangefinder 13. When the bucket descends to the set position, the controller 16 switches to a special working mode to unload the three-chamber hydraulic cylinder 4, and the boom descends quickly to obtain impact kinetic energy.

[0024] It is further preferred in the implementation manner of this embodiment that a flow direction check valve 15 is provided on the pipeline connecting the oil outlet of the third proportional valve 8 and the accumulator 6 .

[0025] In the implementation of this embodiment, it is further preferred that the heavy-duty mechanical arm potential energy recovery system further includes a camera 14, which is fixedly mounted on the bucket and is signal-connected to the controller 16. The camera 14 is configured to collect real-time working images of the bucket, and the video signal of the camera 14 is transmitted to the controller 16, and the working conditions of the bucket are analyzed in real time by machine vision as the third signal for multi-mode control judgment. When the three simultaneously meet the preset conditions, it is judged that the excavator enters a special working mode, which can further enhance the accuracy of the judgment of the working state.

[0026] It is further preferred in the implementation of this embodiment that the heavy-duty mechanical arm potential energy recovery system further includes an overflow valve 9, the accumulator 6 is connected and communicated with the oil tank 10, and the overflow valve 9 is provided on the pipeline communicating between the accumulator 6 and the oil tank 10. The overflow valve 9 plays a role in protecting the heavy-duty mechanical arm potential energy recovery system.

[0027] Example 2

[0028] This embodiment provides a control method for the heavy-duty robotic arm potential energy recovery system using the embodiment 1, including a robotic arm descending condition and a robotic arm ascending condition;

[0029] Robot arm descending condition:

[0030] The first pressure sensor 11 transmits the pressure information of the rod chamber of the monitored three-chamber hydraulic cylinder 4 to the controller 16 in real time, and the controller 16 analyzes the pressure of the rod chamber of the three-chamber hydraulic cylinder 4. The rangefinder 13 transmits the measured distance from the bucket to the working surface to the controller 16 in real time, and the controller 16 analyzes whether the bucket contacts the working surface; based on the pressure information and distance information received by the controller 16, it is jointly determined whether the boom is in a working condition requiring the boom to be lowered; when the pressure signal and the distance signal simultaneously meet the lowering working condition, the controller 16 obtains the working condition information that the mechanical arm is in the mechanical arm lowering; the controller 16 controls the closing of the first proportional valve 5, cuts off the passage between the energy storage chamber of the three-chamber hydraulic cylinder 4 and the accumulator 6, and opens the second proportional valve 7 at the same time, connects the passage between the energy storage chamber of the three-chamber hydraulic cylinder 4 and the oil tank 10, and unloads the energy storage chamber of the three-chamber hydraulic cylinder 4, so that the mechanical arm can be smoothly lowered;

[0031] The robot arm descends and then rises again:

[0032] After the excavator is in the working condition of the mechanical arm descending, the controller 16 continues to collect and analyze the pressure signal and the distance signal. When the controller 16 determines that the preset conditions for the rise of the mechanical arm are met, the controller 16 opens the first proportional valve 5 to connect the energy storage chamber of the three-chamber hydraulic cylinder 4 and the passage of the accumulator 6, and closes the second proportional valve 7 at the same time, cutting off the passage between the energy storage chamber of the three-chamber hydraulic cylinder 4 and the oil tank 10. The hydraulic oil in the accumulator 6 enters the energy storage chamber of the three-chamber hydraulic cylinder 4 through the first proportional valve 5, realizing the rise and confluence of the mechanical arm; when the pressure monitored by the second pressure sensor 12 received by the controller 16 is insufficient, the controller 16 controls the opening of the third proportional valve 8 to realize the pressure closed-loop control, ensuring that the excavator can maintain normal operation in the energy recovery mode. Through the pressure closed-loop control, while adding a switching control system to the excavator, it also supports all functions of the original system, ensuring the integrity of the system, improving the controllability of the whole machine, and allowing the efficient and simple boom potential energy recovery method to not only stay in the laboratory stage, but also provide the possibility of facing the market.

[0033] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A heavy-duty mechanical arm potential energy recovery system, characterized in that: It includes an oil tank, a hydraulic pump, a power element, a three-position four-way solenoid valve, a three-chamber hydraulic cylinder, a first pressure sensor, a second pressure sensor, a first proportional valve, a second proportional valve, a third proportional valve, an accumulator, a rangefinder and a controller; the power element is connected to the hydraulic pump in a transmission manner, the oil inlet of the hydraulic pump is connected and communicated with the oil tank, the oil outlet of the hydraulic pump is connected and communicated with the oil inlet of the three-position four-way solenoid valve, the first oil outlet of the three-position four-way solenoid valve is connected and communicated with the rod chamber of the three-chamber hydraulic cylinder, and the first pressure sensor is arranged on the pipeline connecting the first oil outlet of the three-position four-way solenoid valve and the rod chamber of the three-chamber hydraulic cylinder, the second oil outlet of the three-position four-way solenoid valve is connected and communicated with the rodless chamber of the three-chamber hydraulic cylinder, and the first proportional valve is connected to the oil inlet of the three-chamber hydraulic cylinder. The oil inlet of the first proportional valve and the oil inlet of the second proportional valve are both connected and communicated with the energy storage chamber of the three-chamber hydraulic cylinder, the oil outlet of the first proportional valve is connected and communicated with the accumulator, the second pressure sensor is arranged on the pipeline connecting the oil outlet of the first proportional valve and the accumulator, the oil outlet of the second proportional valve is connected and communicated with the oil tank, the oil inlet of the third proportional valve is connected and communicated with the hydraulic pump, the accumulator is connected and communicated with the oil outlet of the third proportional valve, the rangefinder is fixedly installed on the bucket, the rangefinder is used to detect the distance between the bucket and the ground, the first pressure sensor, the second pressure sensor, the first proportional valve, the second proportional valve, the third proportional valve and the rangefinder are all connected with the controller signal.

2. The heavy-duty mechanical arm potential energy recovery system according to claim 1, characterized in that: A flow direction check valve is arranged on the pipeline connecting the oil outlet of the third proportional valve and the accumulator.

3. The heavy-duty mechanical arm potential energy recovery system according to claim 1, characterized in that: It also includes a camera, which is fixedly mounted on the bucket and is connected to the controller by signal.

4. The heavy-duty mechanical arm potential energy recovery system according to claim 1, characterized in that: It also includes an overflow valve. The accumulator is connected and communicated with the oil tank, and the overflow valve is arranged on the pipeline communicating between the accumulator and the oil tank.

5. A control method using the heavy-duty mechanical arm potential energy recovery system according to any one of claims 1 to 4, characterized in that: Including the robot arm descending working condition and the robot arm ascending working condition; Robot arm descending condition: Based on the pressure information of the rod chamber of the three-chamber hydraulic cylinder monitored by the first pressure sensor and the distance information from the bucket to the excavation surface collected by the rangefinder and received by the controller, jointly determine whether the boom is in a working condition requiring the boom to be lowered; only when the pressure signal and the distance signal simultaneously meet the lowering working condition, the controller obtains the working condition information that the mechanical arm is in the mechanical arm lowering condition; The controller controls the closing of the first proportional valve to cut off the passage between the energy storage chamber of the three-chamber hydraulic cylinder and the accumulator, and at the same time opens the second proportional valve to connect the passage between the energy storage chamber of the three-chamber hydraulic cylinder and the oil tank, thereby unloading the energy storage chamber of the three-chamber hydraulic cylinder, thereby allowing the robotic arm to descend smoothly; The robot arm descends and then rises again: After the excavator is in the condition of lowering the mechanical arm, the controller continues to collect and analyze the pressure signal and the distance signal. When the controller determines that the preset conditions for the ascent of the mechanical arm are met, the controller opens the first proportional valve to connect the energy storage chamber of the three-chamber hydraulic cylinder with the passage of the accumulator, and at the same time closes the second proportional valve to cut off the passage between the energy storage chamber of the three-chamber hydraulic cylinder and the oil tank. The hydraulic oil in the accumulator enters the energy storage chamber of the three-chamber hydraulic cylinder through the first proportional valve to achieve the ascent and merging of the mechanical arm. When the pressure monitored by the second pressure sensor received by the controller is insufficient, the controller controls the opening of the third proportional valve to achieve pressure closed-loop control to ensure that the excavator can maintain normal operation in the energy recovery mode.

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