Control method and system of hydraulic wrist for excavator

Abstract

The invention relates to the technical field of engineering machinery, in particular to a control method and system of a hydraulic wrist for an excavator. According to the method, the mode that a hydraulic valve set is installed on the hydraulic wrist is adopted, all actions of the hydraulic wrist are achieved by controlling a plurality of reversing valves in the hydraulic valve set, only one machine tool working oil way is needed to provide power for the hydraulic wrist, and due to the fact that reversing is completed through all the reversing valves of the hydraulic valve set, the working efficiency is greatly improved. A working oil way of the machine does not need to be reversed, and the requirement can be met only through a one-way oil way. Therefore, the problem that an additional machine tool pipeline of an existing excavator cannot meet the multi-degree-of-freedom action function requirement of a hydraulic wrist is solved, in addition, the reversing valve is controlled by the electric proportional valve, flexibility of action opening is guaranteed, and rotation, inclination, opening and closing and other actions can be operated at the same time under the condition that the pipeline does not need to be disassembled and assembled again.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery, and in particular to a control method and system for a hydraulic wrist for an excavator. Background Art

[0002] The hydraulic wrist is a mechanical attachment installed on an excavator. It can be connected to the end of the excavator's boom directly or through a quick-change connector. It is usually called a hydraulic wrist. The hydraulic wrist comes with an integrated quick-change connector that can quickly connect to a bucket or other tools, thereby improving the versatility of the excavator. It can provide rotation, tilt and other movements for the bucket or tool by using additional hydraulic lines. The tilt and rotation functions can be operated independently or in combination with each other, providing operators with a variety of options for mobile additional tools. From excavation and leveling to demolition and material handling, operators can manipulate the hydraulic wrist to obtain the best working angle and direction without having to readjust the position of the excavator, thereby saving time, improving productivity, and expanding the functions of standard excavators. The hydraulic wrist allows operators to use one machine to perform a range of tasks, reducing the need for multiple devices and improving efficiency on the job site.

[0003] Usually, an excavator is equipped with two bidirectional hydraulic circuits for controlling multifunctional tools. One circuit is used to control the rotation of the tool, and the other circuit is used to control crushing (one-way) or tool opening and closing or other tool movements. That is, one hydraulic circuit can only satisfy one degree of freedom of tool movement. However, for hydraulic wrists, in addition to tilt and rotation functions, they usually have integrated quick-change and optional additional functions such as clamps. In this case, the excavator needs to be equipped with multiple hydraulic pipelines to satisfy multiple functional movements, resulting in bloated pipelines and complex connections, which can easily cause pipeline interference and wear, shortening the service life. Summary of the invention

[0004] The purpose of the present invention is to provide a control method and system for a hydraulic wrist for an excavator, aiming to solve the problem that the additional tool pipeline of the existing excavator cannot meet the multi-degree-of-freedom action function requirements of the hydraulic wrist. The present invention adopts the method of installing a hydraulic valve group on the hydraulic wrist, and realizes each action of the hydraulic wrist by controlling multiple reversing valves in the hydraulic valve group. Therefore, only one tool pipeline is needed to provide power for the hydraulic wrist, and since the reversing is completed by each reversing valve of the hydraulic valve group, the working oil circuit of the tool does not need to be reversed, that is, only a one-way oil circuit is needed to meet the requirements. In addition, the reversing valve is controlled by an electric proportional valve to ensure the flexibility of the action opening, and the rotation, tilting, opening and closing and other actions can be operated simultaneously without re-disassembling the pipeline, so as to achieve the purpose of convenient arrangement and ensuring smooth operation of multiple degrees of freedom.

[0005] In a first aspect, the present invention provides a method for controlling a hydraulic wrist, comprising: The hydraulic valve group is pre-installed on the hydraulic wrist of the excavator, wherein the hydraulic valve group includes a plurality of reversing valves, and the plurality of reversing valves are respectively used to control various actions of the hydraulic wrist; The multiple sliding devices of the joystick are configured to control the respective reversing valves respectively, so as to correspond to the respective actions of the hydraulic wrist; Determine the target reversing valve according to the action to be performed and manipulate the sliding device corresponding to the target reversing valve to move, and send a control signal in a preset proportion to the position of the sliding device 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 according to the control signal; The main pump control current corresponding to the target flow 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 tool solenoid valve of the tool working oil circuit of the excavator; the tool working oil circuit is opened, and the hydraulic wrist performs the corresponding action.

[0006] Optionally, the method also includes: if the action to be performed is a composite action of multiple actions, the controller determines the main pump control current according to the sum of the target flow rates required for each action and determines the valve core control current of each target reversing valve respectively, and the controller outputs the sum of the valve core control currents of each target reversing valve to the tool solenoid valve.

[0007] Optionally, the method further includes: a controller determines a target opening of a control valve core of the tool working oil circuit according to the control signal, and outputs a tool oil circuit valve core control current corresponding to the target opening to the control valve core of the tool working oil circuit.

[0008] Optionally, the hydraulic valve group further includes a switch valve, and the switch valve is connected to a quick-change connector provided with the hydraulic wrist.

[0009] Optionally, a button switch is provided on the operating handle, and the button switch is configured to control the quick-change connector.

[0010] Optionally, the action of the hydraulic wrist includes a tilting action, a rotating action, a first additional action and a second additional action.

[0011] Optionally, the sliding device has two sliding directions and is in a neutral position when no operation is performed. 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 in a preset ratio with 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.

[0012] Optionally, the movement of the sliding device corresponding to the manipulation target reversing valve is achieved through voice recognition control.

[0013] Optionally, if an abnormality occurs during the execution of the hydraulic wrist action, the main pump related parameters and valve related parameters corresponding to each action are adjusted according to preset rules. The main pump related parameters include the main pump flow, 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.

[0014] In a second aspect, the present invention provides a control system for a hydraulic wrist, comprising: A hydraulic valve group, which is used to be pre-installed on the hydraulic wrist, and the hydraulic valve group includes a plurality of reversing valves, and the plurality of reversing valves are respectively used to control various actions of the hydraulic wrist; A communication module is used to configure the multiple sliding devices of the joystick to control the respective reversing valves respectively, so as to control the respective actions of the hydraulic wrist correspondingly; An operation module, used to determine a target reversing valve according to an action to be performed and manipulate a sliding device corresponding to the target reversing valve to move, and a control signal in a preset proportion to the position of the sliding device is sent to a controller; A control module, used for the controller to calculate the target flow rate required for the action and the valve core control current of the target reversing valve according to 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 output the valve core control current to the target reversing valve and the tool solenoid valve of the tool working oil circuit of the excavator; the tool working oil circuit is opened, and the hydraulic wrist executes the corresponding action.

[0015] Compared with the prior art, the present invention has the following beneficial effects: When the control method of the present invention is applied in practice, the excavator does not need to add more tool pipelines. It only needs one tool working oil circuit to provide power for the hydraulic wrist, and then the multi-way reversing valve of the hydraulic valve group can be controlled to realize rotation, tilting, and clamping at the same time. The multi-way reversing valve group is installed on the hydraulic wrist, so that the hydraulic wrist itself has multiple degrees of freedom, thereby making the tool more flexible and can be adapted to the excavator and accessories at the same time. The excavator and accessories do not need any modification. The installation and connection method of the hydraulic valve group of the present invention is simple, which can effectively reduce the interference wear between the pipelines and extend the service life. The present invention can determine the target flow of each action in real time according to the control signal sent by the sliding device through the controller, thereby meeting the needs of different actions and different flow rates. At the same time, the flow loading curve of the tool and the current range of each solenoid valve can be set. Through the coordination of the pump and valve, the impact of the tool is reduced to obtain better control performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a control flow chart of the control method in Example 1.

[0017] Figure 2 This is the control structure logic diagram of the hydraulic wrist in Example 1.

[0018] Figure 3 This is a flow chart of the steps of manually operating the handle in Example 1. DETAILED DESCRIPTION

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0020] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention. Example

[0021] Combination Figure 1 , this embodiment provides a control method of a hydraulic wrist, which includes: Step S1, pre-installing a hydraulic valve group on the hydraulic wrist, wherein the hydraulic valve group includes a plurality of reversing valves, and the plurality of reversing valves are respectively used to control various actions of the hydraulic wrist; Combination Figure 2In this embodiment, the hydraulic valve group includes 4 reversing valves and 1 switch valve, wherein the 4 reversing valves are used to control the rotation, tilt, first additional action, and second additional action of the hydraulic wrist, a total of four actions. In a specific embodiment, the first additional action and the second additional action are clamping action and opening and closing action, respectively. In addition, 1 switch valve is used to connect with the quick-change connector of the hydraulic wrist to open or close the quick change. The reversing valves are all electromagnetic proportional reversing valves.

[0022] Step S2, configuring the plurality of sliding devices of the operating handle to respectively control the respective reversing valves to correspond to the respective actions of the hydraulic wrist; In this embodiment, the operating handle has a total of 4 sliding devices (such as sliding keys or rollers) and at least 1 button switch for the operator to operate with fingers. Each sliding device corresponds to the action of a hydraulic wrist. The sliding device has two sliding directions and is in a neutral position when no operation is performed. 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 in a linear proportion or other curve relationship); a control signal in a preset proportion 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 proportion, wherein one button switch is used to control the quick-change connector provided with the hydraulic wrist.

[0023] Step S3, determining the target reversing valve according to the action to be performed and manipulating the sliding device corresponding to the target reversing valve to move, and sending a control signal in a preset proportion to the position of the sliding device to the controller; The controller is used for signal processing, logical operations and output control signals, and performs the control functions of the excavator and the hydraulic wrist according to the operator's requirements. In addition, an electronic monitor is also provided in this embodiment, which is connected to the controller via the CAN bus. The user can freely configure the various sliding devices on the control handle according to the operating habits to control the action of the hydraulic wrist and display the working status of the hydraulic wrist. The flow rate of the rotation, tilting, clamping and other actions and the current range of the solenoid valve can be set; In a specific embodiment, the movement of the sliding device is realized by intelligent remote control, and a voice recognition module with a built-in high-performance voice recognition chip can be used to identify the control, and the high-performance voice recognition chip can recognize instructions in multiple languages. The operator speaks the preset operation instructions, such as "turn left 10 degrees" and "lift height 50 cm", etc. The voice recognition module converts the recognized instructions into control signals and transmits them to the controller, thereby controlling the output of the hydraulic pump to achieve precise control of the hydraulic wrist; in addition, a gesture recognition camera can also be used, which can capture the gesture movements of the operator in real time. Different gestures are recognized and analyzed through deep learning algorithms, such as clenching a fist to stop, waving a hand to rotate, etc., and the gesture information is converted into control instructions and sent to the control system to achieve flexible control of the hydraulic wrist; and a remote wireless communication module can also be used, which supports wireless communication technologies such as 4G and 5G, and can interact with the remote control terminal for data. The operator can send control instructions through a mobile phone APP or a dedicated remote control software away from the excavator to achieve remote operation of the excavator hydraulic wrist, which is suitable for dangerous environments or long-distance operation scenarios.

[0024] Step S4, the controller calculates the target flow rate required for the action and the valve core control current of the target reversing valve according to the control signal; The target flow rate and the valve core control current are determined according to the position of the sliding device or the handle stroke, and are proportional or other curve relationships. The target flow rate and the valve core control current are calculated by a built-in algorithm.

[0025] Step S5: Output the main pump control current corresponding to the target flow rate to the solenoid valve that controls the main pump displacement, and output the valve core control current to the target reversing valve and the tool solenoid valve of the tool working oil circuit of the excavator; the tool working oil circuit is opened, and the hydraulic wrist performs the corresponding action. The tool working oil circuit can be understood as the main oil circuit, and the tool solenoid valve is a link in the main valve, and the hydraulic oil of each action comes from the main oil circuit.

[0026] When the driver operates other actions of the hydraulic wrist alone, the control method can adopt the above steps. When the driver needs to operate multiple actions of the hydraulic wrist at the same time, the controller determines the main pump control current according to the sum of the target flow required for each action, and determines the valve core control current I of each reversing valve according to the control signal output by each sliding device. bn ,, the valve core control current of each action of the reversing valve is summed to obtain I b =I b1 +I b2 ……+I bn , will I b Output to the implement solenoid valve of the implement working oil circuit.

[0027] In another specific embodiment, in step S6, if an abnormality occurs during the execution of the action of the hydraulic wrist, the main pump related parameters and valve related parameters corresponding to each action are adjusted according to preset rules, and the main pump related parameters include the main pump flow, 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.

[0028] Specifically, during the operation of the machine, if there are problems such as impact, shaking, and jamming that affect controllability, the operator can accurately adjust the main pump-related parameters and the electromagnetic proportional valve-related parameters through the human-machine interaction interface of the electronic monitor. The electronic monitor will send the set parameters to the controller to achieve control of the entire machine. The electronic monitor can select the machine type and the adjustment parameter type. The machine types include hydraulic shears, thumb pliers, tilt buckets, etc.; the adjustment parameter types include main pump flow rates of each action, main pump current ramp loading time, main pump current loading curve and other main pump-related parameters, and electromagnetic proportional valve current range, electromagnetic proportional valve current loading curve and other valve-related parameters. The user first selects the machine type, and then selects the adjustment parameter type. The modified parameters are the parameters corresponding to the machine. The specific implementation method is: (1) Main pump flow: When the machine running speed cannot meet the use requirements, the main pump flow can be adjusted. When using a machine with a large flow demand such as thumb pliers (machine opening and closing), the main pump flow of this machine can be increased on the electronic monitor. When using a machine with a small flow such as a tilt bucket (machine rotation), the main pump flow of this machine can be reduced. Reasonable adjustment of this parameter helps to optimize the power output of the machine during different actions and ensure its smooth operation; (2) Main pump current ramp loading time: When operating the machine, if problems such as hydraulic shock and mechanical vibration occur, the main pump current rise and fall time can be set on the electronic monitor. This parameter affects the current rise and fall rate during the main pump startup and load change process. Proper setting of 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 better match the working requirements of the machine.

[0029] (3) Main pump current loading curve: When problems such as speed change and jamming occur during the operation of the machine, 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 on this basis to change the trend of the main pump current over time during the entire working cycle to achieve the best system performance.

[0030] (4) Solenoid proportional valve current range: Modify the solenoid proportional valve current range so that the working current of the solenoid proportional valve is within a reasonable range, control the size of the solenoid proportional valve spool opening, and thus accurately control the pressure and flow of the hydraulic system to avoid a decrease in control accuracy or damage to valve components due to excessive or insufficient current. The solenoid proportional valve here includes the reversing valve of the hydraulic valve group and the control valve spool of the tool working oil circuit.

[0031] (5) Solenoid proportional valve current loading curve: By adjusting the solenoid proportional valve current loading curve, the current change process of the solenoid proportional valve under different working conditions is further refined. By optimizing the setting of this curve, the solenoid proportional valve can achieve smoother and more accurate hydraulic control when responding to the system control signal, thereby significantly improving the control performance and work efficiency of the machine.

[0032] Combination Figure 3 In a specific embodiment, the driver manually controls the sliding device, and the specific implementation steps of the manual operation handle are: Step 1: The operator configures the corresponding hydraulic wrist action for each sliding device on the operating handle on the electronic monitor; Step 2: The operator manipulates the first slide device to control the first action of the hydraulic wrist. The first signal proportional to the position of the slide device is sent to the controller. The controller calculates the target flow required for this operation and the corresponding main pump control current I according to the input signal of the slide device. a1 , output to the proportional solenoid valve that controls the displacement of the main pump; Step 3: At the same time, the controller calculates the valve core control current I of the tool working oil circuit to achieve the first action b1 ; Step 4: Valve core control current I b1 The output is sent to the solenoid valve of the tool oil circuit, which opens the tool working oil circuit of the excavator, and the hydraulic oil flows to the hydraulic wrist to provide power; at the same time, the valve core controls the current I b1 The reversing valve of the first action of the output to the hydraulic valve group enables the hydraulic wrist to perform the first action; when operating in the reverse direction, only the valve core control current I b1 Output to the other end of the reversing valve to achieve reversing; Step 5: When operating other actions of the hydraulic wrist alone, the control method is the same as the first action; Step 6: While the operator is still controlling the first action of the hydraulic wrist, he continues to manipulate the second slide device to control the second action. The second electrical signal is sent to the controller. In this case, the controller calculates the target flow required for the two actions and the main pump control current Ia=I a1 +I a2 , output to the main pump solenoid valve to adjust the main pump output flow; Step 7: At the same time, the controller calculates the valve core control current I of the tool working oil circuit required to achieve the second action. b2 , and the first action valve core control current I b1 Sum and get I b =I b1 +I b2 , output to the tool oil circuit solenoid valve; Step 8: Valve core control current I b2 The output is sent to the reversing valve corresponding to the second action of the hydraulic valve group on the hydraulic wrist; Step 9: If you continue to operate the third and fourth movements at the same time, the control method is the same.

[0033] Step 10. When operating the machine, if there are problems such as impact, shaking, and jamming that affect the controllability, the operator can accurately adjust the main pump related parameters and electromagnetic proportional valve related parameters through the human-machine interface of the electronic monitor. The electronic monitor will send the set parameters to the controller to achieve control of the entire machine. The electronic monitor can select the machine type and the adjustment parameter type. The machine types include hydraulic shears, thumb pliers, tilt buckets, etc.; the adjustment parameter types include main pump flow of each action, main pump current ramp loading time, main pump current loading curve and other main pump related parameters, and electromagnetic proportional valve current range, electromagnetic proportional valve current loading curve and other valve related parameters. The user first selects the machine type, and then selects the adjustment parameter type. The modified parameters are the parameters corresponding to the machine.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A control method for a hydraulic wrist, characterized in that: include: The hydraulic valve group is pre-installed on the hydraulic wrist of the excavator, wherein the hydraulic valve group includes a plurality of reversing valves, and the plurality of reversing valves are respectively used to control various actions of the hydraulic wrist; The multiple sliding devices of the joystick are configured to control the respective reversing valves respectively, so as to correspond to the respective actions of the hydraulic wrist; Determine the target reversing valve according to the action to be performed and manipulate the sliding device corresponding to the target reversing valve to move, and send a control signal in a preset proportion to the position of the sliding device 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 according to the control signal; The main pump control current corresponding to the target flow 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 tool solenoid valve of the tool working oil circuit of the excavator; the tool working oil circuit is opened, and the hydraulic wrist performs the corresponding action.

2. The control method of the hydraulic wrist according to claim 1, characterized in that: The method also includes: if the action to be executed is a composite action of multiple actions, the controller determines the main pump control current according to the sum of the target flow rates required for each action, the controller determines the valve core control current of each target reversing valve according to the control signal sent by each sliding device, and outputs the sum of the valve core control current of each target reversing valve to the tool solenoid valve.

3. The control method of the hydraulic wrist according to claim 1, characterized in that: The hydraulic valve group also includes a switch valve, and the switch valve is connected to the quick-change joint provided with the hydraulic wrist.

4. The control method of the hydraulic wrist according to claim 3, characterized in that: A button switch is provided on the operating handle, and the button switch is configured to control the quick-change connector.

5. The control method of the hydraulic wrist according to claim 1, characterized in that: The actions of the hydraulic wrist include a tilting action, a rotating action, a first additional action, and a second additional action.

6. The control method of the hydraulic wrist according to claim 1, characterized in that: The first additional action includes a clamping action, and the second additional action includes an opening and closing action.

7. The control method of the hydraulic wrist according to claim 1, characterized in that: The sliding device has two sliding directions and is in a neutral position when not operated. 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 in a preset ratio with 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.

8. The control method of the hydraulic wrist according to claim 1, characterized in that: The movement of the sliding device corresponding to the manipulation target reversing valve is realized through voice recognition control.

9. The control method of the hydraulic wrist according to claim 1, characterized in that: If an abnormality occurs during the execution of the hydraulic wrist action, the main pump related parameters and valve related parameters corresponding to each action are adjusted according to the preset rules. The main pump related parameters include the main pump flow, 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.

10. A control system for a hydraulic wrist, characterized in that: include: A hydraulic valve group, which is used to be pre-installed on the hydraulic wrist, and the hydraulic valve group includes a plurality of reversing valves, and the plurality of reversing valves are respectively used to control various actions of the hydraulic wrist; A communication module is used to configure the multiple sliding devices of the joystick to control the respective reversing valves respectively, so as to control the respective actions of the hydraulic wrist correspondingly; An operation module, used to determine a target reversing valve according to an action to be performed and manipulate a sliding device corresponding to the target reversing valve to move, and a control signal in a preset proportion to the position of the sliding device is sent to a controller; A control module, used for the controller to calculate the target flow rate required for the action and the valve core control current of the target reversing valve according to 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 output the valve core control current to the target reversing valve and the tool solenoid valve of the tool working oil circuit of the excavator; the tool working oil circuit is opened, and the hydraulic wrist executes the corresponding action.

Images