A control method and system for a hydraulic wrist in an excavator

Abstract

This invention relates to the field of engineering machinery technology, specifically to a control method and system for a hydraulic wrist actuator in an excavator. The method employs a hydraulic valve assembly installed on the hydraulic wrist actuator. Various movements of the hydraulic wrist actuator are achieved by controlling multiple directional valves within the hydraulic valve assembly. Only one working oil circuit is needed to power the hydraulic wrist actuator. Furthermore, since directional switching is accomplished by the individual directional valves in the hydraulic valve assembly, the working oil circuit for the implement does not require switching; a single unidirectional oil circuit is sufficient. This solves the problem that existing excavator auxiliary implement piping cannot meet the multi-degree-of-freedom movement requirements of the hydraulic wrist actuator. In addition, the directional valves are controlled by electro-proportional valves, ensuring smooth operation. Rotation, tilting, opening, and closing movements can be performed simultaneously without reinstalling or disassembling the piping.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a control method and system for a hydraulic wrist of an excavator. Background Technology

[0002] A hydraulic wrist is a mechanical attachment mounted on an excavator. It can be directly connected to the end of the excavator's stick or connected via a quick-connect coupling. Commonly referred to as a hydraulic wrist, it features an integrated quick-connect coupling for rapid connection of the bucket or other implements, thus enhancing the excavator's versatility. By using additional hydraulic lines, it can provide rotation, tilting, and other movements to the bucket or implements. Tilting and rotation functions can be operated independently or in combination, providing operators with a variety of mobile attachment options. From digging and leveling to demolition and material handling, operators can manipulate the hydraulic wrist to achieve optimal working angles and directions without needing to readjust the excavator's position, saving time, increasing productivity, and expanding the functionality of a standard excavator. A hydraulic wrist allows operators to perform a range of tasks with a single machine, reducing the need for multiple machines and improving efficiency on the job site.

[0003] Excavators typically come equipped with two bidirectional hydraulic circuits for controlling multi-functional implements. One circuit controls the rotation of the implement, while the other controls breaking (one-way), implementing opening and closing, or other implement actions. In other words, one hydraulic circuit can only satisfy one degree of freedom of implement action. However, hydraulic wrists usually have integrated quick-change functions in addition to tilting and rotating functions, and can be equipped with additional functions such as grippers. In this case, the excavator needs to be equipped with multiple hydraulic lines to satisfy multiple functions, resulting in bloated pipelines, complex connections, and easy interference and wear of pipelines, thus shortening service life. Summary of the Invention

[0004] The purpose of this invention is to provide a control method and system for a hydraulic wrist in excavators. This addresses the issue that existing excavator attachment piping cannot meet the multi-degree-of-freedom movement requirements of the hydraulic wrist. This invention employs a hydraulic valve assembly installed on the hydraulic wrist. By controlling multiple directional valves within the hydraulic valve assembly, the various movements of the hydraulic wrist are achieved. Therefore, only one attachment piping is needed to power the hydraulic wrist. Furthermore, since directional switching is accomplished by the individual directional valves in the hydraulic valve assembly, the working oil circuit of the attachment does not need to be switched; a single-direction oil circuit is sufficient. In addition, the directional valves are controlled by electro-proportional valves, ensuring smooth operation. Rotation, tilting, opening, and closing movements can be performed simultaneously without reinstalling the piping, achieving convenient layout and ensuring smooth multi-degree-of-freedom operation.

[0005] In a first aspect, the present invention provides a method for controlling a hydraulic wrist, comprising:

[0006] A hydraulic valve assembly is pre-installed on the hydraulic wrist of the excavator. The hydraulic valve assembly includes multiple directional valves, which are used to control various movements of the hydraulic wrist.

[0007] The multiple sliding devices of the control handle are configured to control each directional valve respectively, so as to control each movement of the hydraulic wrist.

[0008] The target directional valve is determined according to the action to be performed, and the corresponding sliding device of the target directional valve is manipulated to move. A control signal proportional to the position of the sliding device is sent to the controller.

[0009] The controller calculates the target flow rate required for the action and the valve core control current of the target reversing valve based on the control signal.

[0010] The main pump control current corresponding to the target flow rate is output to the solenoid valve that controls the main pump displacement, and the valve core control current is output to the target reversing valve and the solenoid valve of the excavator's tool working oil circuit; the tool working oil circuit is opened, and the hydraulic wrist performs the corresponding action.

[0011] Optionally, the method further includes: if the action to be performed is a composite action of multiple actions, the controller determines the main pump control current based on the sum of the target flow required for each action and determines the valve core control current of each target directional valve respectively, and the controller outputs the sum of the valve core control currents of each target directional valve to the machine solenoid valve.

[0012] Optionally, the method further includes: the controller determining the target opening degree of the control valve core of the tool working oil circuit according to the control signal, and outputting the control current of the tool oil circuit valve core corresponding to the target opening degree to the control valve core of the tool working oil circuit.

[0013] Optionally, the hydraulic valve assembly further includes a switching valve, which is connected to a quick-connect coupling on the hydraulic wrist.

[0014] Optionally, the control handle is provided with a push-button switch, which is configured to control the quick-connect fitting.

[0015] Optionally, the movements of the hydraulic wrist include tilting movements, rotational movements, a first additional movement, and a second additional movement.

[0016] Optionally, the sliding device has two sliding directions and is in the neutral position when not in operation. The sliding direction of the sliding device corresponds to the valve position of the reversing valve, and the position of the sliding device corresponds to the valve core opening of the reversing valve. A control signal that is proportional to the position of the sliding device can distinguish the sliding direction, and the sensitivity of the sliding device can be adjusted by adjusting the preset ratio.

[0017] Optionally, the movement of the sliding device corresponding to the target reversing valve is achieved through voice recognition control.

[0018] Optionally, if an abnormality occurs during the execution of the hydraulic wrist movement, the main pump-related parameters and valve-related parameters corresponding to each movement are adjusted according to preset rules. The main pump-related parameters include the main pump flow rate, the main pump current ramp loading time, and the main pump current loading curve. The valve-related parameters include the directional valve current range and the directional valve current loading curve.

[0019] Secondly, the present invention provides a control system for a hydraulic wrist, comprising:

[0020] A hydraulic valve assembly for pre-installation on a hydraulic wrist, the hydraulic valve assembly including multiple directional valves, each of which controls a different movement of the hydraulic wrist.

[0021] The communication module is used to configure the multiple sliding devices of the control handle to control each directional valve respectively, so as to control each movement of the hydraulic wrist.

[0022] The operation module is used to determine the target directional valve as needed and manipulate the sliding device corresponding to the target directional valve to move, and send a control signal in a preset proportion to the position of the sliding device to the controller.

[0023] The control module is used by the controller to calculate the target flow rate required for the action and the valve core control current of the target reversing valve based on the control signal.

[0024] The execution module is used to output the main pump control current corresponding to the target flow rate to the solenoid valve that controls the main pump displacement, and to output the valve core control current to the target reversing valve and the implement solenoid valve of the excavator's implement working oil circuit; the implement working oil circuit is opened, and the hydraulic wrist performs the corresponding action.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In practical applications, the control method of this invention eliminates the need for additional implement piping on the excavator. A single implement working oil circuit powers the hydraulic wrist, and simultaneous rotation, tilting, and clamping operations are achieved by controlling the multi-way directional valves of the hydraulic valve assembly. The multi-way directional valve assembly, mounted on the hydraulic wrist, grants it multiple degrees of freedom, making the implement more flexible and adaptable to both the excavator and its attachments without requiring any modifications. The hydraulic valve assembly of this invention features a simple installation and connection method, effectively reducing interference and wear between pipelines and extending service life. This invention allows the controller to determine the target flow rate for each action in real time based on control signals from the sliding device, thus meeting the different flow rate requirements of different actions. It also allows setting the implement's flow rate loading curve and the current range of each solenoid valve. Through pump-valve coordination, it reduces implement impact and achieves superior control performance. Attached Figure Description

[0027] Figure 1 This is a control flowchart of the control method in Example 1.

[0028] Figure 2 The control structure logic diagram of the hydraulic wrist in Example 1 is shown.

[0029] Figure 3 This is a flowchart of the steps for manually operating the handle in Example 1. Detailed Implementation

[0030] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example

[0032] Combination Figure 1 This embodiment provides a control method for a hydraulic wrist, which includes:

[0033] Step S1: Pre-install the hydraulic valve assembly on the hydraulic wrist. The hydraulic valve assembly includes multiple directional valves, which are used to control various movements of the hydraulic wrist.

[0034] Combination Figure 2 In this embodiment, the hydraulic valve group includes four directional valves and one on / off valve. The four directional valves are used to control four actions of the hydraulic wrist: rotation, tilting, a first additional action, and a second additional action. In one specific embodiment, the first additional action and the second additional action are clamping and opening / closing actions, respectively. In addition, the one on / off valve is used to connect to the quick-connect coupling on the hydraulic wrist to open or close the quick-connect coupling. All the directional valves are electromagnetic proportional directional valves.

[0035] Step S2: Configure the multiple sliding devices of the control handle to control each directional valve respectively, so as to control each movement of the hydraulic wrist accordingly.

[0036] In this embodiment, the control handle has four sliding devices (such as slide keys or rollers) and at least one push-button switch for the operator to operate with their fingers. Each sliding device corresponds to the movement of a hydraulic wrist. The sliding device has two sliding directions and is in the neutral position when not in operation. The sliding direction of the sliding device corresponds to the valve position of the reversing valve. The position of the sliding device corresponds to the valve core opening of the reversing valve according to a preset logic (which can be a linear ratio or other curved relationship). The control signal that is proportional to the position of the sliding device can distinguish the sliding direction. The sensitivity of the sliding device can be adjusted by adjusting the preset ratio. One push-button switch is used to control the quick-connect coupling of the hydraulic wrist.

[0037] Step S3: Determine the target directional valve according to the action to be performed and manipulate the sliding device corresponding to the target directional valve to move. Send a control signal in a preset proportion to the position of the sliding device to the controller.

[0038] The controller is used for signal processing, logic operations, and output control signals, executing the control functions of the excavator and hydraulic wrist according to the operator's requirements. In addition, this embodiment also includes an electronic monitor connected to the controller via a CAN bus. The user can freely configure the various sliding devices on the control handle according to their operating habits to control the movement of the hydraulic wrist and display its working status. The flow rate for rotation, tilting, clamping, and other actions, as well as the current range of the solenoid valves, can also be set.

[0039] In one specific embodiment, the movement of the sliding device is achieved through intelligent remote control. This can be achieved using a voice recognition module with a built-in high-performance voice recognition chip, capable of recognizing multiple language commands. The operator speaks preset commands, such as "turn 10 degrees to the left" or "lift 50 centimeters," and the voice recognition module converts these commands into control signals, transmitting them to the controller to control the hydraulic pump output, thus achieving precise control of the hydraulic wrist. Alternatively, a gesture recognition camera can be used, capturing the operator's hand gestures in real time. Deep learning algorithms are used to recognize and analyze different gestures, such as a clenched fist representing stop and a wave representing rotation, converting the gesture information into control commands and sending them to the control system for flexible control of the hydraulic wrist. Furthermore, a remote wireless communication module can be employed, supporting 4G, 5G, and other wireless communication technologies, enabling data interaction with a remote control terminal. Operators can remotely operate the excavator's hydraulic wrist from a distance using a mobile app or dedicated remote control software, suitable for hazardous environments or long-distance operation scenarios.

[0040] Step S4: The controller calculates the target flow rate required for the action and the valve core control current of the target reversing valve based on the control signal.

[0041] The target flow rate and valve core control current are determined by the position of the sliding device or the handle stroke, and are proportional or other curved relationships. Both the target flow rate and valve core control current are calculated by the built-in algorithm.

[0042] Step S5: Output the main pump control current corresponding to the target flow rate to the solenoid valve controlling the main pump displacement, and output the valve core control current to the target directional valve and the implement solenoid valve in the excavator's implement working oil circuit; the implement working oil circuit opens, and the hydraulic wrist performs the corresponding action. The implement working oil circuit can be understood as the main oil circuit, and the implement solenoid valve is a part of the main valve; the hydraulic oil for each action originates from the main oil circuit.

[0043] When the driver performs other actions of the hydraulic wrist independently, the control method follows the steps described above. When the driver needs to perform multiple actions of the hydraulic wrist simultaneously, the controller determines the main pump control current based on the sum of the target flow required for each action, and determines the valve core control current I of each directional valve based on the control signals output by each sliding device. bn The sum of the valve core control currents of each directional valve's operation yields I. b =I b1 +I b2 ...+I bn , will I b The solenoid valve that outputs to the working oil circuit of the tool.

[0044] In another specific embodiment, step S6: if an abnormality occurs during the execution of the hydraulic wrist movement, the main pump related parameters and valve related parameters corresponding to each movement are adjusted according to preset rules. The main pump related parameters include the main pump flow rate, the main pump current ramp loading time, and the main pump current loading curve. The valve related parameters include the reversing valve current range and the reversing valve current loading curve.

[0045] Specifically, during machine operation, if issues affecting operability such as impact, vibration, or jamming occur, the operator can precisely adjust the main pump and electromagnetic proportional valve parameters through the human-machine interface of the electronic monitor. The electronic monitor then sends the set parameters to the controller to achieve overall machine control. The electronic monitor allows selection of machine type and adjustment parameter type. Machine types include hydraulic shears, thumb pliers, and tilting buckets; adjustment parameter types include main pump parameters such as main pump flow rate for each action, main pump current ramp loading time, and main pump current loading curve, as well as valve parameters such as electromagnetic proportional valve current range and electromagnetic proportional valve current loading curve. The user first selects the machine type, then selects the adjustment parameter type; the modified parameters are those corresponding to that machine. The specific implementation method is as follows:

[0046] (1) Main pump flow rate: When the machine's operating speed cannot meet the usage requirements, the main pump flow rate can be adjusted. When using high-flow-rate tools such as thumb pliers (machine opening and closing), the main pump flow rate of this tool can be increased via the electronic monitor. When using low-flow-rate tools such as tilting buckets (machine rotation), the main pump flow rate of this tool can be decreased. Reasonable adjustment of this parameter helps to optimize the power output of the machine during different actions and ensure its stable operation;

[0047] (2) Main pump current ramp loading time: When hydraulic shock and mechanical vibration occur during the operation of the machine, the rise and fall time of the main pump current can be set on the electronic monitor. This parameter affects the rise and fall rate of the current during the start-up and load change process of the main pump. Properly setting this time can effectively avoid hydraulic shock and mechanical vibration caused by sudden current changes and ensure a smooth transition of the system. By setting a reasonable ramp loading time, the output characteristics of the main pump can be better matched with the working requirements of the machine.

[0048] (3) Main pump current loading curve: When problems such as speed change or jamming occur during machine operation, the main pump current loading curve can be adjusted on the electronic monitor. This curve has a factory default curve on the electronic monitor, and the operator can adjust it to change the trend of the main pump current over time throughout the entire working cycle in order to achieve the best system performance.

[0049] (4) Electromagnetic proportional valve current range: Modify the current range of the electromagnetic proportional valve to make the working current of the electromagnetic proportional valve within a reasonable range, control the valve core opening size of the electromagnetic proportional valve, and thus accurately control the pressure and flow of the hydraulic system, avoiding the decrease in control accuracy or damage to valve components due to excessive or insufficient current. The electromagnetic proportional valve here includes the directional valve of the hydraulic valve group and the control valve core of the working oil circuit of the tool.

[0050] (5) Electromagnetic proportional valve current loading curve: By adjusting the electromagnetic proportional valve current loading curve, the change process of the electromagnetic proportional valve current under different working conditions can be further refined. By optimizing the setting of this curve, the electromagnetic proportional valve can achieve smoother and more precise hydraulic control when responding to the system control signal, thereby significantly improving the machine's operating performance and working efficiency.

[0051] Combination Figure 3 In one specific embodiment, the sliding device is manually controlled by the driver. The specific steps for manually operating the handle are as follows:

[0052] Step 1: The operator configures the corresponding hydraulic wrist movements for each sliding device on the operating handle using the electronic monitor;

[0053] Step 2: The operator manipulates the first sliding device to control the first movement of the hydraulic wrist. A first signal proportional to the position of the sliding device is sent to the controller. The controller calculates the target flow rate required for this operation and the corresponding main pump control current I based on the input signal from the sliding device. a1 , Output to the proportional solenoid valve that controls the displacement of the main pump;

[0054] Step 3: Simultaneously, the controller calculates the valve core control current I of the working oil circuit of the tool to achieve the first action. b1 ;

[0055] Step 4, Valve core control current I b1 The output is sent to the solenoid valve in the implement hydraulic circuit, opening the implement working hydraulic circuit of the excavator, allowing hydraulic oil to flow to the hydraulic wrist and provide power; at the same time, the valve core controls the current I. b1 The directional valve, which outputs the first action to the hydraulic valve assembly, allows the hydraulic wrist to perform the first action; in reverse operation, only the valve core control current I is needed. b1 The output is sent to the other end of the reversing valve to achieve reversal;

[0056] Step 5: When operating other movements of the hydraulic wrist independently, the control method is the same as for the first movement;

[0057] Step 6: While the operator is still controlling the first movement of the hydraulic wrist, continue manipulating the second sliding device to control the second movement. A second electrical signal is sent to the controller. In this case, the controller calculates the target flow rate required for both movements and the main pump control current Ia = I a1 +I a2 The output flow rate of the main pump is adjusted by sending the solenoid valve to the main pump.

[0058] Step 7: Simultaneously, the controller calculates the valve core control current I required for the machine's working oil circuit to achieve the second action. b2 The valve core control current I of the first actionb1 Summing yields I b =I b1 +I b2 The output is sent to the solenoid valve in the hydraulic circuit of the machine.

[0059] Step 8, Valve core control current I b2 The output is then sent to the directional valve corresponding to the second action of the hydraulic valve assembly on the hydraulic wrist.

[0060] Step 9: If the third and fourth movements are operated simultaneously, the control method is the same.

[0061] Step 10: If issues affecting operability such as impact, vibration, or jamming occur during machine operation, the operator can precisely adjust the main pump and electromagnetic proportional valve parameters through the human-machine interface of the electronic monitor. The electronic monitor then sends the set parameters to the controller to achieve overall machine control. The electronic monitor allows selection of machine type and adjustment parameter type. Machine types include hydraulic shears, thumb pliers, and tilting buckets; adjustment parameter types include main pump parameters such as main pump flow rate for each action, main pump current ramp loading time, and main pump current loading curve; and valve parameters such as electromagnetic proportional valve current range and electromagnetic proportional valve current loading curve. The user first selects the machine type, then selects the adjustment parameter type; the modified parameters will then be those corresponding to that machine.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling a hydraulic wrist, characterized in that, include: A hydraulic valve assembly is pre-installed on the hydraulic wrist of the excavator. The hydraulic valve assembly includes multiple directional valves, which are used to control various movements of the hydraulic wrist. The multiple sliding devices of the control handle are configured to control each directional valve respectively, so as to control each movement of the hydraulic wrist. The target directional valve is determined according to the action to be performed, and the corresponding sliding device of the target directional valve is manipulated to move. A control signal proportional to the position of the sliding device is sent to the controller. The controller calculates the target flow rate required for the action and the valve core control current of the target reversing valve based on the control signal. The main pump control current corresponding to the target flow rate is output to the solenoid valve that controls the main pump displacement, and the valve core control current is output to the target reversing valve and the solenoid valve of the excavator's tool working oil circuit; the tool working oil circuit is opened, and the hydraulic wrist performs the corresponding action; The sliding device has two sliding directions and is in the middle position when not in operation. The sliding direction of the sliding device corresponds to the valve position of the reversing valve, and the position of the sliding device corresponds to the valve core opening of the reversing valve. A control signal that is proportional to the position of the sliding device can distinguish the sliding direction, and the sensitivity of the sliding device can be adjusted by adjusting the preset ratio. The method further includes: If the action to be performed is a composite action of multiple actions, the controller determines the main pump control current based on the sum of the target flow required by each action, and determines the valve core control current of each target directional valve based on the control signals sent by each sliding device, and outputs the sum of the valve core control currents of each target directional valve to the machine solenoid valve. If an abnormality occurs during the execution of the hydraulic wrist movement, the relevant parameters of the main pump and valves corresponding to each movement are adjusted according to preset rules. The relevant parameters of the main pump include the main pump flow rate, the main pump current ramp loading time, and the main pump current loading curve. The relevant parameters of the valves include the reversing valve current range and the reversing valve current loading curve.

2. The control method for a hydraulic wrist according to claim 1, characterized in that, The hydraulic valve assembly also includes a switching valve, which is connected to a quick-connect coupling on the hydraulic wrist.

3. The control method for a hydraulic wrist according to claim 2, characterized in that, The control handle is equipped with a push-button switch, which is configured to control the quick-connect fitting.

4. The control method for a hydraulic wrist according to claim 1, characterized in that, The movements of the hydraulic wrist include tilting movements, rotational movements, a first additional movement, and a second additional movement.

5. The control method for a hydraulic wrist according to claim 4, characterized in that, The first additional action includes a clamping action, and the second additional action includes an opening and closing action.

6. The control method for a hydraulic wrist according to claim 1, characterized in that, The movement of the sliding device corresponding to the target reversing valve is achieved through voice recognition control.

7. A control system for a hydraulic wrist, characterized in that, A control method for performing a hydraulic wrist according to any one of claims 1-6, the control system comprising: A hydraulic valve assembly for pre-installation on a hydraulic wrist, the hydraulic valve assembly including multiple directional valves, each of which controls a different movement of the hydraulic wrist. The communication module is used to configure the multiple sliding devices of the control handle to control each directional valve respectively, so as to control each movement of the hydraulic wrist. The operation module is used to determine the target directional valve as needed and manipulate the sliding device corresponding to the target directional valve to move, and send a control signal in a preset proportion to the position of the sliding device to the controller. The control module is used by the controller to calculate the target flow rate required for the action and the valve core control current of the target reversing valve based on the control signal. The execution module is used to output the main pump control current corresponding to the target flow rate to the solenoid valve that controls the main pump displacement, and to output the valve core control current to the target reversing valve and the implement solenoid valve of the excavator's implement working oil circuit; the implement working oil circuit is opened, and the hydraulic wrist performs the corresponding action.

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