A two-stage luffing adjustment working arm and a cooperative control method thereof

Abstract

This invention discloses a two-stage pitch-adjustable boom and its coordinated control method, relating to the field of engineering machinery equipment. It includes a base, a first boom, a second boom, and a two-stage pitch-adjustment mechanism. One end of the first boom is hinged to the base, and the other end is hinged to the second boom. The other end of the second boom is connected to a work execution device. The two-stage pitch-adjustment mechanism consists of multiple rods and actuators, respectively connecting the base, the first boom, and the second boom. The first actuator extends and retracts to drive the first boom to rotate, achieving the first stage of pitch adjustment. The second actuator drives the second boom to rotate, achieving the second stage of pitch adjustment. The top rod, second connecting rod, third connecting rod, and bottom rod form a quadrilateral conformal mechanism with the first boom. During the second stage of pitch adjustment, geometric constraints maintain stability, keeping the posture unchanged after the first stage adjustment, avoiding mutual interference between the two stages of adjustment, enabling large angle changes, expanding the working range, improving working efficiency, and enhancing the stability of the boom.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery and equipment technology, and in particular to a two-stage pitch-adjustable boom and its coordinated control method. Background Technology

[0002] In the fields of modern infrastructure construction and resource extraction, engineering machinery is widely used in mining, tunnel excavation, and various construction projects. As a core component of many engineering machines such as shovels, crushers, and excavators, the performance of the boom plays a decisive role in the equipment's operating efficiency and applicability. With increasingly complex engineering operating environments, higher requirements are being placed on the boom's working range, load-bearing capacity, stability, and control precision.

[0003] Currently, most construction machinery booms use a single-stage hydraulic cylinder to directly drive the boom's pitch. This driving method has many drawbacks. Due to the required working range, the stroke of the single-stage hydraulic cylinder is often too long, resulting in a bulky cylinder. This not only increases equipment cost and space occupation but also burdens the hydraulic system and reduces its reliability. Furthermore, during large-angle adjustments, the transmission angle deteriorates, transmission efficiency decreases significantly, and the boom's stability and accuracy are severely affected. In addition, traditional boom configurations, such as four-bar linkages (4 links, 1 degree of freedom), have a very small working range, making it difficult to meet the needs of multi-degree-of-freedom operations; seven-bar linkages (7 links, 2 degrees of freedom), while increasing degrees of freedom, have a small number of closed loops, a single force transmission path, and insufficient stiffness under heavy loads; nine-bar linkages (9 links, 2 degrees of freedom), while balancing structure and performance to some extent, have limited force transmission paths, and still suffer from concentrated impact loads and insufficient impact resistance during large-angle operations. Therefore, there is an urgent need to develop a new type of boom and its control method to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a two-stage pitch-adjustable boom and its coordinated control method to solve the problems existing in the prior art, achieve large angle changes, effectively expand the working range of the boom, effectively improve working efficiency, and effectively enhance the stability of the boom.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a two-stage pitch-adjustable boom, comprising: a base, a first boom, a second boom, and a two-stage pitch-adjustment mechanism. One end of the first boom is hinged to the base, and the other end is hinged to one end of the second boom. The end of the second boom away from the first boom is connected to a work execution device. The two-stage pitch-adjustment mechanism includes a first driver, a second driver, a base rod, a first connecting rod, a second connecting rod, a third connecting rod, and a top rod. One end of the base rod is hinged to the base. The first connecting rod has a first hinge point, a second hinge point, and a third hinge point. The first hinge point is used to hingely connect to the end of the base rod away from the base. The second hinge point is located in the middle of the first connecting rod and is hinged to both the second connecting rod and the third connecting rod. The third hinge point is hinged to the first boom. One end of the first driver is hinged to the base, and the other end is hinged to the first boom. The first driver drives the first boom to rotate around its hinge point with the base by telescopic extension, thereby achieving the first stage of pitch adjustment. The top rod has a fourth hinge point, a fifth hinge point, and a sixth hinge point. The fourth hinge point is hinged to the ends of the second connecting rod and the third connecting rod away from the second hinge point. The fifth hinge point is located in the middle of the top rod and is hinged to the first boom. The sixth hinge point is hinged to one end of the second driver, and the other end of the second driver is hinged to the second boom. The second driver drives the top rod to move by extension and retraction, thereby driving the second boom to rotate around its hinge point with the first boom to achieve a second-level pitch adjustment. The top rod, the second connecting rod, the third connecting rod, the base rod, and the first boom form a quadrilateral conformal mechanism. During the second-level pitch adjustment driven by the second driver, the quadrilateral conformal mechanism maintains stability through the relative geometric constraints of its quadrilateral sides and corners, so that the posture of the first boom relative to the base after the first-level pitch adjustment remains unchanged, thus not interfering with the first-level adjusted posture during the second-level pitch adjustment.

[0006] Preferably, the first connecting rod is an L-shaped rod or a bend rod, the first hinge point is located at one end of the first connecting rod, the second hinge point is located at the bend of the first connecting rod, and the third hinge point is located at the other end of the first connecting rod; the top rod is an L-shaped rod or a bend rod, the fourth hinge point is located at one end of the top rod, the fifth hinge point is located at the bend of the top rod, and the sixth hinge point is located at the other end of the top rod.

[0007] Preferably, the operation execution device includes a third boom, a third driver, a fourth connecting rod, a fifth connecting rod, a first execution connecting rod, a second execution connecting rod, a fourth driver, and an execution element. One end of the third boom is hinged to the end of the second boom away from the first boom, and the other end is hinged to the execution element. One end of the third driver is hinged to the second boom, and the other end is hinged to the third boom. One end of the fourth driver is hinged to the third boom. One end of the fourth connecting rod and the fifth connecting rod are hinged to the third boom. One end of the first execution connecting rod and the second execution connecting rod are hinged to the execution element. The ends of the first execution connecting rod and the second execution connecting rod away from the execution element, the ends of the fourth connecting rod and the fifth connecting rod away from the third boom, and the end of the fourth driver away from the second boom are hinged together.

[0008] Preferably, the first boom, the second boom, and the top rod are hinged at the same hinge point to form a first compound hinge structure, and the fourth connecting rod, the fifth connecting rod, the first actuating connecting rod, the second actuating connecting rod, and the fourth driver are hinged at the same hinge point to form a second compound hinge structure.

[0009] Preferably, the actuator is any one of an impact hammer, a bucket, or a lifting ring.

[0010] Preferably, the first driver, the second driver, the third driver, and the fourth driver are all any one of hydraulic cylinders, electric cylinders, or pneumatic cylinders.

[0011] Preferably, the base rod and the base, the base rod and the first connecting rod, the first connecting rod and the first boom, the top rod and the first boom, the first boom and the second boom, and the second driver and the second boom are all hinged by pins.

[0012] The present invention also provides a cooperative control method for controlling a working arm with two-stage pitch adjustment as described in any of the preceding claims, comprising the following steps: Command acquisition and kinematic decoupling: The controller acquires the target pitch attitude command and decouples the target pitch attitude command kinematically based on the mechanism kinematic algorithm, decomposing it into a first-level pitch target value and a second-level pitch target value; the kinematic decoupling calculates the first-level pitch target value corresponding to the first actuator and the second-level pitch target value corresponding to the second actuator based on the structural parameters of the working arm, the length of each arm, the position of each hinge point, and the geometric constraint relationship of each link, so that the first-level pitch adjustment undertakes the function of large stroke coarse adjustment, and the second-level pitch adjustment undertakes the function of high-precision fine adjustment. The total pitch adjustment range exceeding the limit of a single actuator stroke is achieved by superimposing the strokes of the two actuators; First-level closed-loop drive control: The controller drives the first actuator to rotate the first boom. The first detection element detects the actual attitude value of the first boom relative to the base in real time and feeds it back to the controller. The controller compares the actual attitude value with the first-level pitch target value and adjusts the output of the first actuator in real time through a closed-loop control algorithm until the first boom reaches the first-level pitch target value. Second-level closed-loop drive control: The controller drives the second actuator to rotate the second boom. The second detection element detects the actual attitude value of the second boom relative to space in real time and feeds it back to the controller. The controller compares the actual attitude value with the second-level pitch target value and adjusts the output of the second actuator in real time through a closed-loop control algorithm until the second boom reaches the second-level pitch target value. Dual Redundancy Detection and Collaborative Closed-Loop Compensation: The first detection element and the second detection element constitute a dual redundancy detection system. The controller continuously compares the actual attitude values ​​fed back by the first detection element and the second detection element with their respective target values, calculates the control deviation in real time, and synchronously adjusts the outputs of the first driver and the second driver based on the control deviation. This compensates for attitude changes caused by mechanism deformation and load disturbance in real time, eliminates the inherent coupling interference between the two stages of motion, and enables the end of the working arm to accurately reach the target working posture.

[0013] Preferably, the first-level closed-loop drive control and the second-level closed-loop drive control are two-level parallel and coordinated control. During the first-level pitch adjustment of the first boom, the controller simultaneously starts the drive control of the second driver, so that the first-level adjustment and the second-level adjustment are executed in time overlap to shorten the total adjustment time. The kinematic decoupling specifically includes: the controller establishes forward and inverse kinematic models of the mechanism based on the structural parameters of the working arm, and solves the target displacement of the first driver and the second driver in reverse according to the target pitch attitude command. The target displacement of the first driver corresponds to the large-stroke coarse adjustment displacement, and the target displacement of the second driver corresponds to the high-precision fine adjustment displacement.

[0014] Preferably, the closed-loop control algorithm is a PID control algorithm or a fuzzy PID control algorithm. The controller controls the output flow or output force of the first driver and the second driver by adjusting the opening of the electro-hydraulic proportional valve or the servo valve. The first detection element and the second detection element are any one or more combinations of angle sensors, inertial measurement units, or displacement sensors. The first detection element is installed on the first boom near its hinge point with the base, and the second detection element is installed on the second boom near its hinge point with the first boom.

[0015] The present invention achieves the following technical effects compared to the prior art: This invention provides a two-stage pitch-adjustable boom and its collaborative control method. Through a two-stage independent adjustment structure, the first stage handles large-stroke coarse adjustments, while the second stage handles high-precision fine adjustments. Their cooperation overcomes the stroke limitations of a single actuator, effectively expanding the boom's total pitch adjustment range to meet large-angle operation requirements. Furthermore, the geometric constraints of a quadrilateral conformal mechanism ensure that the second-stage adjustment does not interfere with the already completed first-stage adjustment, achieving motion decoupling at the structural level and avoiding the problems of excessive stroke, bulky size, and deteriorated transmission angle associated with traditional single-stage hydraulic cylinders. Simultaneously, through parallel collaborative control and a dual-redundant closed-loop compensation strategy, the inherent coupling interference between the two stages of motion is further eliminated. This compensates for attitude errors caused by mechanism deformation and load disturbances, significantly improving the boom's attitude control accuracy and operational stability. Parallel adjustment also shortens the overall adjustment time, effectively improving operational efficiency and better adapting to complex, heavy-load engineering environments. This addresses the technical pain points of traditional booms, such as small working range, insufficient rigidity, and poor impact resistance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A simplified structural diagram of the two-stage pitch-adjustable working arm provided by this invention; Figure 2 Schematic diagram of the structure of the two-stage pitch-adjustable working arm provided by the present invention Figure 1 ; Figure 3 Schematic diagram of the structure of the two-stage pitch-adjustable working arm provided by the present invention Figure 2 ; Figure 4 A schematic diagram of the working state when the angle between the two-stage pitch-adjustable working arm and the ground is at its minimum, as provided by the present invention. Figure 5 A schematic diagram of the working state when the angle between the two-stage pitch-adjustable working arm and the ground is at its maximum, as provided by this invention. Figure 6 is a hardware block diagram of the working arm control system provided by the present invention; Figure 7 is a flowchart of the working arm control method provided by the present invention.

[0018] In the diagram: 1. Base; 2. Bottom rod; 3. First hydraulic cylinder; 4. First piston rod; 5. First connecting arm; 6. First connecting rod; 7. Second connecting rod; 8. Top rod; 9. Second piston rod; 10. Second hydraulic cylinder; 11. Second connecting arm; 12. Third hydraulic cylinder; 13. Third piston rod; 14. Third connecting arm; 15. Fourth hydraulic cylinder; 16. Fourth piston rod; 17. Fourth connecting rod; 18. First actuating connecting rod; 19. Actuating component. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a two-stage pitch-adjustable boom and its coordinated control method to solve the problems existing in the prior art, achieve large angle changes, effectively expand the working range of the boom, effectively improve working efficiency, and effectively enhance the stability of the boom.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 This embodiment provides a two-stage pitch-adjustable working arm, such as Figures 1-5As shown, the device includes: a base, a first boom, a second boom, and a two-stage pitch adjustment mechanism. One end of the first boom is hinged to the base, and the other end is hinged to one end of the second boom. The end of the second boom away from the first boom is connected to the work execution device. The two-stage pitch adjustment mechanism includes a first driver, a second driver, a base rod, a first connecting rod, a second connecting rod, a third connecting rod, and a top rod. One end of the base rod is hinged to the base. The first connecting rod has a first hinge point, a second hinge point, and a third hinge point. The first hinge point is used to connect the base rod away from the base. One end of the first connecting rod is hinged to the base, and the second hinge point is located in the middle of the first connecting rod. The second hinge point is hinged to both the second and third connecting rods. The third hinge point is hinged to the first boom. One end of the first driver is hinged to the base, and the other end is hinged to the first boom. The first driver drives the first boom to rotate around its hinge point with the base by telescopic movement to achieve the first stage of pitch adjustment. The top rod has a fourth, a fifth, and a sixth hinge point. The fourth hinge point is connected to both the second and third connecting rods. The end of the connecting rod furthest from the second hinge point is hinged. The fifth hinge point is located in the middle of the top rod and is hinged to the first boom. The sixth hinge point is hinged to one end of the second driver, and the other end of the second driver is hinged to the second boom. The second driver drives the top rod to move by extending and retracting, thereby driving the second boom to rotate around its hinge point with the first boom to achieve a second-stage pitch adjustment. The top rod, the second connecting rod, the third connecting rod, the bottom rod, and the first boom form a quadrilateral conformal mechanism. During the second-stage pitch adjustment driven by the second actuator, the quadrilateral conformal mechanism maintains stability through the relative geometric constraints of its quadrilateral sides and corners. This ensures that the posture of the first boom relative to the base remains unchanged after the first-stage pitch adjustment, thus preventing interference with the already adjusted posture during the second-stage pitch adjustment. This two-stage pitch adjustment mechanism, using two actuators to drive the first and second booms respectively, achieves two-stage pitch adjustment of the boom, effectively expanding the boom's pitch angle range and improving its operational flexibility and adaptability. The quadrilateral conformal mechanism ensures that the posture of the first stage adjustment remains unaffected during the second-stage adjustment, improving the accuracy and stability of the boom's posture adjustment and avoiding posture deviations caused by mutual interference during the adjustment process. This allows the boom to be positioned more precisely to the required working position.

[0023] In a preferred embodiment, the first connecting rod is an L-shaped rod or a bend rod, with the first hinge point located at one end of the first connecting rod, the second hinge point located at the bend of the first connecting rod, and the third hinge point located at the other end of the first connecting rod; the top rod is also an L-shaped rod or a bend rod, with the fourth hinge point located at one end of the top rod, the fifth hinge point located at the bend of the top rod, and the sixth hinge point located at the other end of the top rod. The L-shaped or bend rod design optimizes the spatial layout while meeting structural connection requirements, facilitating the rational arrangement of components within a limited space and enhancing the structural compactness. This shape design helps to transmit driving force more effectively, ensuring the stability and reliability of the mechanism's movement, and enabling the working arm to operate stably under different working conditions.

[0024] In a preferred embodiment, the work execution device includes a third boom, a third driver, a fourth connecting rod, a fifth connecting rod, a first execution connecting rod, a second execution connecting rod, a fourth driver, and an actuator. One end of the third boom is hinged to the end of the second boom away from the first boom, and the other end is hinged to the actuator. One end of the third driver is hinged to the second boom, and the other end is hinged to the third boom. One end of the fourth driver is hinged to the third boom. One end of the fourth connecting rod and the fifth connecting rod are hinged to the third boom. One end of the first and second execution connecting rods is hinged to the actuator. The ends of the first and second execution connecting rods away from the actuator, the ends of the fourth and fifth connecting rods away from the third boom, and the end of the fourth driver away from the second boom are hinged together. This detailed structural design of the work execution device allows the actuator to be flexibly connected to the end of the working arm, and through the coordinated action of multiple drivers and connecting rods, enables precise movement of the actuator in different directions and angles. This design enhances the adaptability of the boom to different tasks, enabling it to meet various operational needs such as excavation, crushing, and hoisting, thus further expanding the boom's functional range.

[0025] In a preferred embodiment, the first boom, the second boom, and the top rod are hinged at the same hinge point, forming a first compound hinge structure. The fourth connecting rod, the fifth connecting rod, the first actuating connecting rod, the second actuating connecting rod, and the fourth actuator are hinged at the same hinge point, forming a second compound hinge structure. The compound hinge structure reduces the number of hinge points, improves the overall integrity and compactness of the structure, and helps reduce its complexity and weight. Simultaneously, the compound hinge structure can more effectively distribute stress, enhance the load-bearing capacity of the boom under large loads, improve the stability and reliability of the boom structure, and extend the service life of the boom.

[0026] In a preferred embodiment, the actuator is any one of an impact hammer, a bucket, or a lifting ring. The selection of multiple actuators allows the boom to be quickly changed according to different work scenarios and task requirements, greatly improving the boom's versatility and flexibility. Whether it's ore crushing in mining or material excavation or hoisting in construction, the operation can be completed efficiently by changing the appropriate actuator.

[0027] In a preferred embodiment of this invention, the first, second, third, and fourth actuators are all hydraulic cylinders, electric cylinders, or pneumatic cylinders. This selection of multiple drive methods allows the work arm to choose the most suitable drive method based on actual needs in different working environments and application scenarios. Hydraulic cylinders are characterized by high output force and good stability, making them suitable for heavy-duty operations; electric cylinders offer high precision and convenient control, making them suitable for operations requiring high precision; pneumatic cylinders offer fast response and lower cost, making them suitable for occasions with high speed requirements and relatively small loads. This selectivity improves the adaptability and application range of the work arm.

[0028] In a preferred embodiment, the first actuator includes a first hydraulic cylinder and a first piston rod; the second actuator includes a second hydraulic cylinder and a second piston rod; the third actuator includes a third hydraulic cylinder and a third piston rod; and the fourth actuator includes a fourth hydraulic cylinder and a fourth piston rod. One end of the cylinder of the first hydraulic cylinder is hinged to the base, and the other end extends out of the first piston rod and is hinged to the first boom. One end of the cylinder of the second hydraulic cylinder is hinged to the second boom, and the other end extends out of the second piston rod and is hinged to the sixth hinge point of the top rod. One end of the cylinder of the third hydraulic cylinder is hinged to the second boom, and the other end extends out of the third piston rod and is hinged to the third boom. One end of the cylinder of the fourth hydraulic cylinder is hinged to the third boom, and the other end extends out of the fourth piston rod and is hinged to the second double-hinged structure. The hydraulic cylinder-driven structure has a large output force and strong impact resistance, which is very suitable for the needs of heavy-duty engineering operations. It can stably withstand the impact of large loads and ensure the reliability of the boom operation.

[0029] In a preferred embodiment, the base rod and the base, the base rod and the first connecting rod, the first connecting rod and the first boom, the top rod and the first boom, the first boom and the second boom, and the second drive and the second boom are all connected by pin hinges. This pin hinge connection provides flexible rotational connections between the components, ensuring that the various parts of the boom can move relative to each other according to design requirements, achieving pitch adjustment and other actions. Simultaneously, the pin hinge structure is simple, easy to install, maintain, and replace, reducing the maintenance cost and repair difficulty of the boom, and improving its maintainability and reliability.

[0030] Example 2 This embodiment also provides a two-stage pitch adjustment boom control system, such as... Figure 6 As shown, it includes: The human-machine interface terminal (HMI) is used to receive target pitch attitude commands input by the operator. The HMI provides the operator with an intuitive and convenient operating interface, enabling the operator to accurately input the target pitch attitude commands required by the working arm according to the actual operation requirements, thereby realizing manual control of the working arm's attitude and improving the convenience and accuracy of operation.

[0031] The controller incorporates a kinematic decoupling unit and a collaborative closed-loop control unit. The kinematic decoupling unit decomposes the target pitch attitude command into a first-level pitch target value and a second-level pitch target value. The collaborative closed-loop control unit synchronously adjusts the output of each stage of the actuators based on dual-redundant detection feedback signals. The kinematic decoupling unit, built into the controller, can rationally decompose complex target pitch attitude commands into first-level and second-level pitch target values ​​according to the structural characteristics and kinematic principles of the workarm, providing accurate target settings for the collaborative control of the two-level pitch adjustment. The collaborative closed-loop control unit, based on dual-redundant detection feedback signals, monitors and synchronously adjusts the output of each stage of the actuators in real time, ensuring the coordination and accuracy of each stage of the workarm's movements, effectively eliminating coupling interference between the two stages of adjustment, and improving the accuracy and stability of the workarm's attitude control.

[0032] The first drive and detection module comprises a first driver and a first detection element. The first detection element is mounted on the first boom and is used to detect the actual attitude of the first boom in real time and feed it back to the controller. The first drive and detection module realizes the driving and attitude detection functions of the first boom. The first detection element monitors the actual attitude of the first boom in real time and feeds the information back to the controller, enabling the controller to understand the motion state of the first boom in a timely manner so as to make real-time adjustments according to the target value, ensuring that the first boom moves according to the predetermined first-level pitch target value, thereby improving the accuracy and controllability of the first-level pitch adjustment.

[0033] The second drive and detection module comprises a second driver and a second detection element. The second detection element is mounted on the second boom and is used to detect the actual posture of the second boom in real time and feed it back to the controller. The first and second detection elements form a dual-redundant detection system. The controller is signal-connected to the human-machine interface terminal, the first driver, the first detection element, the second driver, and the second detection element. The second drive and detection module drives and detects the posture of the second boom, forming a dual-redundant detection system together with the first drive and detection module. The dual-redundant detection system greatly improves the reliability and accuracy of posture detection. Even if one detection element fails, the other detection element can still provide accurate posture information, ensuring that the controller can continuously and accurately acquire the actual posture of the boom, thereby achieving stable and reliable control of the boom and improving the fault tolerance and operational reliability of the entire control system.

[0034] In a preferred embodiment, the controller is any one of a programmable logic controller (PLC), an embedded controller, or an industrial computer; the human-machine interface (HMI) terminal is any one of a touchscreen, an industrial control panel, or a remote control terminal. The availability of various types of controllers and HMI terminals allows the work arm control system to be customized according to different application scenarios and requirements. PLCs are suitable for routine control tasks in industrial environments, featuring high reliability and flexible programming; embedded controllers are small in size and low in power consumption, suitable for applications with high space and power consumption requirements; industrial computers are powerful and can handle complex computational and control tasks. Touchscreen HMI terminals offer intuitive and convenient operation; industrial control panels are robust and durable, suitable for harsh industrial environments; remote control terminals enable remote operation, improving operator safety and operational flexibility. This diverse selection enhances the adaptability and practicality of the control system.

[0035] In a preferred embodiment, both the first and second actuators are equipped with independent electro-hydraulic proportional valves or servo valves. The controller controls the opening of the electro-hydraulic proportional valves or servo valves via PWM signals or analog signals. These valves precisely control the flow and pressure of the actuators, thereby achieving precise control of the movement of the first and second booms. By adjusting the valve opening via PWM signals or analog signals, the controller can adjust the actuator output in real time and precisely according to actual needs, making the boom's pitch adjustment smoother and more accurate. This meets the requirements of different operating scenarios for boom motion accuracy, improving the boom's operational performance and work quality.

[0036] Example 3 This embodiment also provides a collaborative control method for controlling a working arm with two-stage pitch adjustment as described in Embodiment 1, such as... Figure 7 As shown, it includes the following steps: Command acquisition and kinematic decoupling: The controller acquires the target pitch attitude command and, based on a mechanism kinematics algorithm, kinematically decouples the command, decomposing it into a first-level pitch target value and a second-level pitch target value. Kinematic decoupling calculates the first-level pitch target value corresponding to the first actuator and the second-level pitch target value corresponding to the second actuator based on the structural parameters of the boom, the length of each boom section, the position of each hinge point, and the geometric constraints of each link. This allows the first-level pitch adjustment to handle large-stroke coarse adjustment, while the second-level pitch adjustment handles high-precision fine adjustment. The total pitch adjustment range exceeds the limit of a single actuator by superimposing the strokes of the two actuators. Through precise kinematic decoupling, the structural characteristics of the boom are fully utilized, and the tasks of the first and second-level pitch adjustments are rationally allocated, enabling the boom to break through the stroke limitations of a single actuator and achieve a wider range of pitch adjustments. This task allocation method improves adjustment efficiency while ensuring adjustment accuracy, laying the foundation for subsequent precise control.

[0037] First-level closed-loop drive control: The controller drives the first actuator to rotate the first boom. A first detection element continuously monitors the actual attitude value of the first boom relative to the base and feeds it back to the controller. The controller compares the actual attitude value with the first-stage pitch target value and adjusts the output of the first actuator in real time using a closed-loop control algorithm until the first boom reaches the first-stage pitch target value. This closed-loop drive control achieves precise control of the first boom's movement. Through real-time detection and feedback, the controller can promptly adjust the output of the first actuator to compensate for attitude deviations caused by various factors, ensuring that the first boom accurately reaches the predetermined first-stage pitch target value, thus improving the accuracy and stability of the first-stage pitch adjustment.

[0038] Second-stage closed-loop drive control: The controller drives the second actuator to rotate the second boom. The second detection element continuously monitors the actual attitude value of the second boom relative to space and feeds it back to the controller. The controller compares the actual attitude value with the second-level pitch target value and adjusts the output of the second actuator in real time through a closed-loop control algorithm until the second boom reaches the second-level pitch target value. Similarly, the second-level closed-loop drive control ensures the accuracy of the second boom's movement. This real-time detection and closed-loop adjustment mechanism enables the second boom to accurately reach the second-level pitch target value, further improving the overall pitch adjustment accuracy of the boom and ensuring that the boom can be precisely positioned to the required attitude.

[0039] Dual redundancy detection and collaborative closed-loop compensation: The first and second detection elements constitute a dual-redundant detection system. The controller continuously compares the actual attitude values ​​fed back by the first and second detection elements with their corresponding target values, calculates the control deviation in real time, and synchronously adjusts the outputs of the first and second drivers based on the control deviation. This compensates for attitude changes caused by mechanism deformation and load disturbances in real time, eliminating inherent coupling interference between the two stages of motion. This ensures that the end effector of the working arm accurately reaches the target working posture. The dual-redundant detection system improves the reliability of attitude detection; even if one detection element fails, the other can still provide accurate information. Collaborative closed-loop compensation can respond in real time to attitude changes caused by factors such as mechanism deformation and load disturbances, eliminate coupling interference between the two stages of motion, and ensure that the end effector of the working arm accurately reaches the target working posture, significantly improving the overall reliability and accuracy of the working arm attitude control.

[0040] Two-level parallel cooperative control: The first-level closed-loop drive control and the second-level closed-loop drive control are two-stage parallel and coordinated control. During the first-stage pitch adjustment of the boom, the controller simultaneously activates the drive control of the second actuator, allowing the first and second stages of adjustment to overlap in time, thus shortening the total adjustment time. Kinematic decoupling specifically includes: the controller establishing forward and inverse kinematic models based on the boom's structural parameters; and inversely solving for the target displacements of the first and second actuators based on the target pitch attitude command. The target displacement of the first actuator corresponds to the large-stroke coarse adjustment displacement, while the target displacement of the second actuator corresponds to the high-precision fine adjustment displacement. This two-stage parallel and coordinated control effectively shortens the total adjustment time and improves the boom's response speed. By establishing forward and inverse kinematic models, the target displacements of the two actuators are accurately determined, further optimizing the coordinated effect of the two-stage adjustment. This allows the boom to reach the target attitude more efficiently, meeting the needs of rapid and precise adjustment in actual operations.

[0041] Closed-loop control algorithm and detection element: The closed-loop control algorithm is either a PID control algorithm or a fuzzy PID control algorithm. The controller controls the output flow or output force of the first and second actuators by adjusting the opening of the electro-hydraulic proportional valve or servo valve. The first and second detection elements are any one or more combinations of angle sensors, inertial measurement units, or displacement sensors. The first detection element is installed on the first boom near its hinge point with the base, and the second detection element is installed on the second boom near its hinge point with the first boom. The use of mature PID or fuzzy PID control algorithms enables precise adjustment of the actuator outputs to adapt to different working scenarios and control requirements. The selectivity of multiple detection elements and their reasonable installation positions ensure accurate acquisition of boom attitude information, providing reliable data support for precise control and further improving the adaptability and accuracy of the boom collaborative control method.

[0042] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A two-stage luffing adjustable working arm, characterized by: include: Base; A first boom, one end of which is hinged to the base, and the other end of which is hinged to one end of a second boom; The second boom has a working device connected to the end of the second boom that is away from the first boom; A two-stage pitch adjustment mechanism includes a first driver, a second driver, a base rod, a first connecting rod, a second connecting rod, a third connecting rod, and a top rod. One end of the base rod is hinged to the base. The first connecting rod has a first hinge point, a second hinge point, and a third hinge point. The first hinge point is used to hingely connect to the end of the base rod away from the base. The second hinge point is located in the middle of the first connecting rod and is hinged to both the second and third connecting rods. The third hinge point is hinged to the first boom. One end of the first driver is hinged to the base, and the other end is hinged to the first boom. The first driver... The first boom is rotated around its hinge point with the base via telescopic drive to achieve a first-level pitch adjustment. The top rod has a fourth hinge point, a fifth hinge point, and a sixth hinge point. The fourth hinge point is hinged to the end of the second connecting rod and the third connecting rod away from the second hinge point. The fifth hinge point is located in the middle of the top rod and is hinged to the first boom. The sixth hinge point is hinged to one end of the second driver. The other end of the second driver is hinged to the second boom. The second driver drives the top rod to move by telescopic drive, thereby driving the second boom to rotate around its hinge point with the first boom to achieve a second-level pitch adjustment. The top rod, the second connecting rod, the third connecting rod, the bottom rod, and the first boom form a quadrilateral conformal mechanism. During the second-stage pitch adjustment driven by the second driver, the quadrilateral conformal mechanism maintains stability through the relative geometric constraints of its quadrilateral sides and corners, ensuring that the posture of the first boom relative to the base remains unchanged after the first-stage pitch adjustment, thus not interfering with the already adjusted posture during the second-stage pitch adjustment.

2. A two-stage luffing regulated work arm according to claim 1, characterized in that: The first connecting rod is an L-shaped rod or a bend rod, the first hinge point is located at one end of the first connecting rod, the second hinge point is located at the bend of the first connecting rod, and the third hinge point is located at the other end of the first connecting rod; the top rod is an L-shaped rod or a bend rod, the fourth hinge point is located at one end of the top rod, the fifth hinge point is located at the bend of the top rod, and the sixth hinge point is located at the other end of the top rod.

3. The two-stage luffing regulated work arm of claim 1, characterized by: The operation execution device includes a third boom, a third driver, a fourth connecting rod, a fifth connecting rod, a first execution connecting rod, a second execution connecting rod, a fourth driver, and an execution element. One end of the third boom is hinged to the end of the second boom away from the first boom, and the other end is hinged to the execution element. One end of the third driver is hinged to the second boom, and the other end is hinged to the third boom. One end of the fourth driver is hinged to the third boom. One end of the fourth connecting rod and the fifth connecting rod are hinged to the third boom. One end of the first execution connecting rod and the second execution connecting rod are hinged to the execution element. The ends of the first execution connecting rod and the second execution connecting rod away from the execution element, the ends of the fourth connecting rod and the fifth connecting rod away from the third boom, and the end of the fourth driver away from the second boom are hinged together.

4. A two-stage luffing regulated work arm according to claim 3, characterized in that: The first boom, the second boom, and the top rod are hinged at the same hinge point to form a first compound hinge structure. The fourth connecting rod, the fifth connecting rod, the first actuating connecting rod, the second actuating connecting rod, and the fourth driver are hinged at the same hinge point to form a second compound hinge structure.

5. A two-stage luffing regulated work arm according to claim 3, characterized in that: The actuator is any one of an impact hammer, a bucket, or a lifting ring.

6. A two-stage luffing regulated work arm according to claim 3, characterized in that: The first driver, the second driver, the third driver, and the fourth driver are all any one of hydraulic cylinders, electric cylinders, or pneumatic cylinders.

7. The two-stage luffing regulated work arm of claim 1, wherein: The bottom rod and the base, the bottom rod and the first connecting rod, the first connecting rod and the first boom, the top rod and the first boom, the first boom and the second boom, and the second driver and the second boom are all hinged by pins.

8. A method of coordinated control for controlling a two-stage luffing adjusted working arm according to any one of claims 1 to 7, characterized in that: Includes the following steps: Command acquisition and kinematic decoupling: The controller acquires the target pitch attitude command and decouples the target pitch attitude command kinematically based on the mechanism kinematic algorithm, decomposing it into a first-level pitch target value and a second-level pitch target value; the kinematic decoupling calculates the first-level pitch target value corresponding to the first actuator and the second-level pitch target value corresponding to the second actuator based on the structural parameters of the working arm, the length of each arm, the position of each hinge point, and the geometric constraint relationship of each link, so that the first-level pitch adjustment undertakes the function of large stroke coarse adjustment, and the second-level pitch adjustment undertakes the function of high-precision fine adjustment. The total pitch adjustment range exceeding the limit of a single actuator stroke is achieved by superimposing the strokes of the two actuators; First-level closed-loop drive control: The controller drives the first actuator to rotate the first boom. The first detection element detects the actual attitude value of the first boom relative to the base in real time and feeds it back to the controller. The controller compares the actual attitude value with the first-level pitch target value and adjusts the output of the first actuator in real time through the closed-loop control algorithm until the first boom reaches the first-level pitch target value. Second-level closed-loop drive control: The controller drives the second actuator to rotate the second boom. The second detection element detects the actual attitude value of the second boom relative to space in real time and feeds it back to the controller. The controller compares the actual attitude value with the second-level pitch target value and adjusts the output of the second actuator in real time through the closed-loop control algorithm until the second boom reaches the second-level pitch target value. Dual Redundancy Detection and Collaborative Closed-Loop Compensation: The first detection element and the second detection element constitute a dual redundancy detection system. The controller continuously compares the actual attitude values ​​fed back by the first detection element and the second detection element with their respective target values, calculates the control deviation in real time, and synchronously adjusts the outputs of the first driver and the second driver based on the control deviation. This compensates for attitude changes caused by mechanism deformation and load disturbance in real time, eliminates the inherent coupling interference between the two stages of motion, and enables the end of the working arm to accurately reach the target working posture.

9. The two-stage pitch-adjustable boom according to claim 1, characterized in that: The first-level closed-loop drive control and the second-level closed-loop drive control are two-level parallel and coordinated control. During the first-level pitch adjustment of the first boom, the controller simultaneously starts the drive control of the second driver, so that the first-level adjustment and the second-level adjustment are executed in time overlap, thereby shortening the total adjustment time. The kinematic decoupling specifically includes: the controller establishing forward and inverse kinematic models of the mechanism based on the structural parameters of the working arm, and inversely solving the target displacement of the first driver and the second driver according to the target pitch attitude command. The target displacement of the first driver corresponds to the large stroke coarse adjustment displacement, and the target displacement of the second driver corresponds to the high precision fine adjustment displacement.

10. The two-stage pitch-adjustable boom according to claim 1, characterized in that: The closed-loop control algorithm is a PID control algorithm or a fuzzy PID control algorithm. The controller controls the output flow or output force of the first driver and the second driver by adjusting the opening of the electro-hydraulic proportional valve or the servo valve. The first detection element and the second detection element are any one or more combinations of angle sensors, inertial measurement units or displacement sensors. The first detection element is installed on the first boom near its hinge point with the base, and the second detection element is installed on the second boom near its hinge point with the first boom.

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