A mobile hydraulic robotic arm and its control method

Abstract

This invention provides a mobile hydraulic robotic arm and its control method. The robotic arm includes a base with an independently driven, movable chassis design, providing mobility. The boom assembly consists of multiple booms connected in series via rotary joints, each equipped with a hydraulic actuator for drive function. A sensing and positioning system acquires information about the robotic arm's own state and the surrounding three-dimensional environment, providing data support for intelligent control. The control system is mounted on the boom and connected to each subsystem via cables, enabling coordinated motion control based on state and environmental information. The hydraulic system comprises three core components: a hydraulic power unit corresponding to each actuator; a hydraulic actuator unit integrated on the actuator's port valve block, including a servo valve, pressure sensor, and emergency lock-up valve; and a hydraulic auxiliary unit providing oil storage, temperature control, and filtration functions. This invention solves key problems such as power coupling, response delay, and low energy efficiency.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic robotic arm control technology, specifically relating to a mobile hydraulic robotic arm and its control method. Background Technology

[0002] Currently, robotic arms have replaced manual labor in many fields. However, in heavy-duty applications such as construction machinery, mining machinery, and agricultural machinery, although hydraulic robotic arms are widely used due to their high power density, their development still faces severe technical bottlenecks. Traditional heavy-duty hydraulic robotic arms generally use centralized hydraulic systems, that is, a central pump station supplies oil to multiple actuators (hydraulic cylinders or motors) through complex pipelines and valve groups.

[0003] This architecture has inherent flaws: First, the shared hydraulic lines cause severe dynamic coupling interference when the actuators move, and changes in the load of one joint directly affect the pressure and flow of other joints, making it difficult to improve control accuracy; second, the long hydraulic lines and multi-stage valve groups cause significant pressure loss and dynamic response delay, making the robotic arm move slowly and difficult to achieve fast and precise automated control; finally, the system needs to maintain a high-pressure state at all times to cope with peak loads, resulting in low energy efficiency and causing huge energy waste most of the time.

[0004] Therefore, most existing heavy-duty hydraulic robotic arms remain in a semi-automated stage where they are manually operated by operators. Their work efficiency, construction quality, and operational accuracy are far from meeting the demands of modern industry for automated and precise operations, and have also brought about high labor costs and potential safety risks. Summary of the Invention

[0005] This invention provides a mobile hydraulic robotic arm and a control method to solve the above-mentioned technical problems.

[0006] In a first aspect, the present invention provides a mobile hydraulic robotic arm, the mobile hydraulic robotic arm comprising a boom assembly, a base, a sensing and positioning system, a hydraulic system and a control system;

[0007] The base is a movable chassis with an independent drive device;

[0008] The boom assembly is mounted on the base and consists of at least two booms connected in series via rotary joints, with each rotary joint integrating a hydraulic actuator for driving.

[0009] The perception and positioning system is used to acquire the robotic arm's own state information and the three-dimensional environment information around the robotic arm.

[0010] The control system is mounted on the boom assembly and is electrically connected to the hydraulic system, the base, and all sensors and hydraulic actuators on the boom assembly via cables. It is used to coordinate the movement of the mobile hydraulic robotic arm by combining its own status information and external environmental information.

[0011] The hydraulic system is mounted on the boom assembly, and the hydraulic system includes:

[0012] Multiple hydraulic power units correspond one-to-one with each hydraulic actuator of the boom assembly. Each hydraulic power unit consists of a servo motor, a fixed-displacement hydraulic pump connected to the servo motor via a bell-shaped cover and a coupling, an accumulator installed at the outlet of the fixed-displacement hydraulic pump, and a first pressure sensor.

[0013] Multiple hydraulic actuators are integrated on the oil port valve block of the corresponding hydraulic actuator. Each hydraulic actuator includes a servo valve, a second pressure sensor installed at each of the two working oil ports of the servo valve, and an electromagnetic switch valve for emergency locking.

[0014] The hydraulic auxiliary unit includes an oil tank with a liquid level and temperature sensor, a forced refrigeration cycle system consisting of a fan and compressor driven by a frequency converter, and a filter installed on the main return oil line.

[0015] Optionally, the sensing and positioning system includes:

[0016] The environmental perception unit consists of at least one lidar installed at the base or end of the boom assembly, used to scan and build a three-dimensional point cloud map around the robotic arm in real time.

[0017] The global positioning unit consists of an RTK receiver and a receiver antenna mounted on the boom assembly, used to obtain the absolute position of the robotic arm in the world coordinate system;

[0018] The attitude sensing unit consists of multiple inertial measurement units installed on the base and each boom, and is used to measure the pitch, roll and yaw angles of the base and each boom in real time.

[0019] The body sensing unit consists of a joint angle sensor coaxially mounted with each rotary joint and a cylinder stroke sensor built into each hydraulic actuator, used to measure the real-time joint pose information of each rotary joint.

[0020] Optionally, each rotary joint of the boom assembly employs an integrated structure, the integrated structure comprising:

[0021] Hydraulic actuators are either hydraulic cylinders or hydraulic motors;

[0022] An integrated valve block is installed at the oil port of the hydraulic actuator. The servo valve, the second pressure sensor, and the solenoid switch valve are all installed on the integrated valve block.

[0023] One of the joint angle sensors or hydraulic cylinder stroke sensors in the body sensing unit;

[0024] An inertial measurement unit within the attitude sensing unit;

[0025] In addition, integrated wiring harnesses that connect all components in the integrated structure to the control system and integrated piping for hydraulic connections.

[0026] Optionally, the control system includes:

[0027] The main controller is electrically connected to the sensing and positioning system and is used to fuse multi-source sensor data and perform motion planning including vibration prediction and suppression based on a pre-stored multibody dynamics model, generating a drive torque sequence and hydraulic energy supply strategy.

[0028] Multiple joint controllers correspond one-to-one with each hydraulic actuator. The command input terminals of all joint controllers are connected to the main controller and used to receive the drive torque sequence. The feedback input terminals of all joint controllers are connected to the sensors in the corresponding body sensing unit and hydraulic actuator unit. All joint controllers are equipped with a hydraulic stiffness observer for online analysis of hydraulic stiffness.

[0029] The constant pressure and temperature controller is connected to the main controller and is used to receive and execute the hydraulic energy supply strategy, control the speed of the servo motor in each hydraulic power unit in a closed loop, and adjust the cooling power according to the predictive thermal management instructions of the main controller.

[0030] The safety controller monitors all sensor signals and sends a lock-up command to the solenoid valves of all hydraulic actuators when a hardware fault is detected. The lock-up command has higher authority than control commands issued by all other controllers in the control system.

[0031] In a second aspect, the present invention also provides a control method for a mobile hydraulic robotic arm, applied to the mobile hydraulic robotic arm described in any one of the first aspects, the method comprising the following steps:

[0032] The sensing and positioning system is used to obtain the mobile hydraulic robotic arm's own state information and the surrounding three-dimensional environment information;

[0033] The control system processes its own state information and three-dimensional environment information, and plans the final motion trajectory of the mobile hydraulic robotic arm.

[0034] The control system generates a hydraulic energy supply strategy based on the final motion trajectory and instructs multiple hydraulic power units in the hydraulic system to provide power to the boom assembly according to the hydraulic energy supply strategy.

[0035] The control system commands multiple hydraulic actuators in the hydraulic system to drive the boom assembly to move along the final motion trajectory.

[0036] Optionally, the process of using the control system to process its own state information and three-dimensional environment information, and to plan the final motion trajectory of the mobile hydraulic robotic arm, includes the following steps:

[0037] The main controller integrates multi-source sensor data acquired by the environmental perception unit, global positioning unit, attitude perception unit, and body perception unit, and generates an initial motion trajectory based on the preset task objective.

[0038] The main controller calls a pre-stored multibody dynamics model containing the dynamic parameters of the boom assembly, takes the initial motion trajectory as input, and predicts the vibration response of each boom in the boom assembly when executing the initial motion trajectory.

[0039] If the predicted vibration response exceeds the preset response threshold, the velocity and acceleration curves of the initial motion trajectory are adjusted by the main controller and an optimization algorithm to generate the final motion trajectory that actively suppresses structural vibration.

[0040] Optionally, the step of using the control system to generate a hydraulic energy supply strategy based on the final motion trajectory and instructing multiple hydraulic power units in the hydraulic system to provide power to the boom assembly according to the hydraulic energy supply strategy includes the following steps:

[0041] By using the main controller and combining the final motion trajectory and multibody dynamics model, the time-varying drive torque sequence of each rotary joint during the process of realizing the final motion trajectory is calculated;

[0042] The main controller parses the drive torque sequence into the power demand curve of each hydraulic power unit.

[0043] The main controller generates a feedforward energy scheduling strategy for the servo motor in each hydraulic power unit based on the power demand curve.

[0044] The constant pressure and temperature controller executes a feedforward energy scheduling strategy. When the output power of the rotary joint exceeds the preset first power threshold, the speed of the servo motor corresponding to the rotary joint is increased in advance, and the accumulator is pressurized by a quantitative hydraulic pump. When the output power of the rotary joint is lower than the preset second power threshold, the speed of the servo motor corresponding to the rotary joint is reduced. The first power threshold is greater than the second power threshold.

[0045] During the execution of the feedforward energy scheduling strategy, the first pressure value of the first pressure sensor in each hydraulic power unit is continuously monitored by a constant pressure and temperature controller, and the speed of the servo motor is corrected in a closed loop based on the first pressure value.

[0046] Optionally, the step of parsing the drive torque sequence into the power demand curve of each hydraulic power unit via the main controller includes the following steps:

[0047] The main controller acquires real-time joint pose information provided by the joint angle sensor and the cylinder stroke sensor in the body sensing unit. The real-time joint pose information includes relative rotation angle and extension length.

[0048] The main controller establishes a nonlinear mapping model from the driving torque of each rotary joint to the required output force of the corresponding hydraulic actuator based on the geometric parameters of the boom assembly.

[0049] The main controller converts the drive torque sequence into the target output force sequence required by each hydraulic actuator in real time through a nonlinear mapping model.

[0050] The main controller converts the target output force sequence into the target differential pressure sequence required by the inlet and outlet ports of each hydraulic actuator based on the effective working area of ​​each hydraulic actuator.

[0051] The main controller combines the target differential pressure sequence with the target motion speed of the hydraulic actuator to calculate the power demand curve of each hydraulic power unit over time.

[0052] Optionally, the step of using the control system to command multiple hydraulic actuators in the hydraulic system to drive the boom assembly to move along the final motion trajectory includes the following steps:

[0053] The main controller sends the final motion trajectory to each joint controller as the target instruction for the position control of the joint controller.

[0054] For any joint controller, preliminary closed-loop control is performed on the servo valve in the hydraulic actuator unit by using the key controller and combining the target command and real-time joint pose information.

[0055] During the initial closed-loop control process, the joint controller reads the second pressure value of the corresponding second pressure sensor and calculates the real-time differential pressure acting on the hydraulic actuator based on the second pressure value.

[0056] The joint controller utilizes a built-in hydraulic stiffness observer to analyze the dynamic relationship between the servo valve control commands, real-time differential pressure, and real-time joint pose information, and calculates the equivalent hydraulic stiffness of the current rotary joint.

[0057] When the equivalent hydraulic stiffness is lower than the preset hydraulic stiffness threshold, the joint controller adjusts the closed-loop control parameters of the initial closed-loop control according to the equivalent hydraulic stiffness, and requests the constant pressure and constant temperature controller to increase the reference pressure of the corresponding hydraulic power unit for stiffness compensation.

[0058] Optionally, the method further includes the following steps:

[0059] The safety controller monitors in real time and in parallel the readings of all sensors in the sensing and positioning system and the hydraulic system, as well as the actual movement trajectory of the mobile hydraulic robotic arm.

[0060] If the value of any sensor exceeds the preset danger threshold or the deviation between the actual movement trajectory and the final movement trajectory exceeds the preset deviation threshold, the safety controller will send a locking command with the highest authority to the solenoid valves of all hydraulic actuators on the boom assembly.

[0061] When the solenoid valve receives the lock-up command, it locks the oil circuits of all hydraulic actuators to freeze the current state of the boom assembly.

[0062] The beneficial effects of this invention are:

[0063] This invention completely solves the inherent defects of traditional centralized systems by adopting a distributed hydraulic architecture. Each actuator is equipped with an independent power unit, fundamentally eliminating power coupling interference between joints and achieving true independent control, significantly improving control accuracy and response speed. By placing power sources nearby, this invention significantly shortens the hydraulic transmission distance, effectively reducing pressure loss and transmission delay, enabling the robotic arm to achieve rapid and precise action response, meeting the stringent requirements of automated operations. This invention employs an intelligent control strategy of on-demand power supply, avoiding the energy waste of traditional systems that continuously maintain high pressure. It dynamically adjusts the output of each power unit according to actual load demand, significantly improving system energy efficiency. This invention integrates an advanced sensing and positioning system and an intelligent control system, achieving a leap from semi-automation to full automation, not only improving work efficiency and construction quality but also significantly reducing labor costs and safety risks. The mobile design of this invention enhances the applicability and flexibility of the equipment, enabling it to adapt to various complex working conditions. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the overall structure of a mobile hydraulic robotic arm in one embodiment of this application.

[0065] Figure 2 This is a schematic diagram of the structure of the first boom base end and the base in one embodiment of this application.

[0066] Figure 3This is a schematic diagram of the structure of the second boom and the third boom in one embodiment of this application.

[0067] Figure 4 This is one embodiment of the present application. Figure 3 An enlarged schematic diagram of the second boom section.

[0068] Figure 5 This is a schematic diagram of the internal architecture of the control system in one embodiment of this application.

[0069] Figure 6 This is a schematic diagram of the hydraulic system in one embodiment of this application.

[0070] Figure 7 This is a flowchart illustrating a mobile hydraulic robotic arm control method in one embodiment of this application.

[0071] Explanation of reference numerals in the attached figures:

[0072] 1. Base; 2. Boom assembly; 21. First boom; 22. Second boom; 23. Third boom; 3. Control system; 4. Hydraulic system; 51. First lidar; 52. First attitude sensor; 53. Relative positioning device; 54. Second lidar; 55. Horizontal positioner; 56. First hollow magnetic ring angle encoder; 6. Base rotation joint; 7. Spring telescopic shock absorber; 8. Hydraulic motor; 81. Rotary drive oil pipe; 82. Rotary drive wiring harness port; 83. Rotary drive pressure sensor; 84. Rotary drive solenoid valve; 85. Rotary drive brake valve block; 86. Rotary drive hydraulic servo valve; 9. Counterweight block; 10. Upper base; 11. First RTK; 31. Electrical control box; 32. Remote controller; 33. Warning light; 34. Third lidar; 211. First boom cylinder; 212. First boom cylinder oil pipe; 213. First boom rotating joint; 214. Second hollow magnetic ring angle encoder; 215. Fourth lidar; 216. First tilt sensor; 12. Second RTK; 221. Second boom cylinder; 222. Second boom rotating joint; 223. Third hollow magnetic ring angle encoder; 224. Fifth lidar; 231. Third boom cylinder; 232. Third boom cylinder hose; 233. First ultrasonic radar; 234. Second tilt sensor; 235. Third boom rotating joint; 236. Fourth hollow magnetic ring angle encoder; 13. Flow meter; 14. Second ultrasonic radar; 15. Discharge port rotating joint; 16. Second attitude sensor; 17. Infrared camera; 18. Automatic valve; 19. Discharge hose; 225. Second boom cylinder hose; 226. Second... 227. Boom cylinder wiring harness port; 2211. Third ultrasonic radar; 2212. Second boom cylinder pressure sensor; 2213. Second boom cylinder solenoid switch valve; 2214. Second boom cylinder brake valve block; 2215. Second boom cylinder hydraulic servo valve; 2216. Second boom cylinder stroke sensor; 41. Oil tank; 42. Liquid level and temperature sensor; 43. Oil outlet pipe; 44. Forced cooling circulation system; 45. Accumulator; 46. Hydraulic drive power valve block; 47. Servo drive module; 48. Integrated servo motor; 49. Gear pump. Detailed Implementation

[0073] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0074] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0075] Reference Figure 1 This invention provides a mobile hydraulic robotic arm that features high precision, high efficiency, high dynamic response, and high safety, enabling it to meet the needs of automated operations in open, unstructured, and complex working environments. Figure 1 As shown, the mobile hydraulic robotic arm includes a boom assembly 2, a base 1, a sensing and positioning system, a hydraulic system 4, and a control system 3. These five systems cooperate to form the technical solution of this invention. The base 1 serves as the mobile platform for the entire device, providing load-bearing capacity and off-road mobility. The boom assembly 2 is the main actuator for realizing the operational functions and is mounted on the base 1. The hydraulic system 4 provides the power source for the movement of the boom assembly 2, and some of its components are also mounted on the base 1. The sensing and positioning system endows the robotic arm with the ability to perceive its environment and its own state. The control system 3 acts as the brain of the entire device, coordinating the various subsystems to achieve complex autonomous or semi-autonomous operational tasks.

[0076] The base 1 is a movable chassis with an independent drive unit. In this embodiment, as... Figure 1 and Figure 2 As shown, the base 1 adopts a tracked structure to adapt to different working ground environments, such as construction sites, mines, or rugged fields. An upper base 10 is mounted on the base 1, and the boom assembly 2 is connected to the upper base 10 via a base rotation joint 6. The base 1 integrates an independent power and drive system, such as an internal combustion engine or a high-power electric motor driving a hydraulic pump, which in turn drives the tracks via a hydraulic motor, thereby achieving autonomous movement of the mobile hydraulic robotic arm. The base 1 also has structures for supporting and balancing the entire robotic arm, such as retractable hydraulic outriggers and spring-loaded shock absorbers 7, as well as a counterweight 9 located at the rear of the upper base 10 to balance the unbalanced torque generated by the movement of the boom assembly 2. Figure 2As shown, the base 1 also integrates some components of the perception and positioning system, such as the first lidar 51 installed at the front of the chassis and the second lidar 54 installed at the rear, as well as the relative positioning device 53 and the horizontal positioner 55, which are used to collect terrain data and obstacle information to provide decision-making basis for subsequent movement path planning and safe obstacle avoidance. At the same time, the base 1 is also equipped with a first attitude sensor 52, which is used to monitor the pitch and roll attitude of the chassis in real time. This is crucial for compensating for the impact of chassis attitude changes on the end accuracy of the boom assembly 2 when operating on uneven ground.

[0077] The boom assembly 2 is mounted on the base 1 and consists of at least two booms connected in series via rotary joints, each rotary joint integrating a hydraulic actuator for drive. In this embodiment, as... Figure 1 and Figure 3 As shown, the boom assembly 2 consists of multiple boom sections connected in series, including the first boom 21, the second boom 22, and the third boom 23, and achieves overall rotational movement through a base rotation joint 6 mounted on the base 1. The first boom 21 is connected to the upper base 10 via the first boom rotation joint 213; the second boom 22 is connected to the first boom 21 via the second boom rotation joint 222; and the third boom 23 is connected to the second boom 22 via the third boom rotation joint 235. This multi-degree-of-freedom configuration gives the robotic arm a large working range and flexible posture adjustment capabilities. Different types of hydraulic actuators are used for the connecting joints between the booms, depending on the motion. For example, the rotary joint used to achieve boom pitch motion uses a high-thrust hydraulic cylinder as its actuator. Specifically, the first boom rotation joint 213 is driven by the first boom cylinder 211, the second boom rotation joint 222 is driven by the second boom cylinder 221, and the third boom rotation joint 235 is driven by the third boom cylinder 231. The corresponding hydraulic lines include the first boom cylinder oil pipe 212, the second boom cylinder oil pipe 225, and the third boom cylinder oil pipe 232. The base rotation joint 6, used to achieve the overall left and right rotation of the boom assembly 2 on the base 1, uses a hydraulic motor 8 as its hydraulic actuator, which drives the slewing bearing through a reducer. Integrating the hydraulic actuator directly at the joint significantly shortens the length of the hydraulic lines, reduces the negative impacts of the elasticity, viscosity, and inertia of the hydraulic oil, thereby improving the system's dynamic response speed and control accuracy.

[0078] The boom itself can adopt an integrated, foldable truss structure. This design reduces its weight while ensuring structural rigidity, thereby improving effective load capacity and reducing energy consumption. Channels for accommodating conduits can be designed inside or outside the boom, effectively protecting hydraulic hoses and cables from scratches or damage in harsh working environments, thus improving system reliability. At the end of boom assembly 2, i.e., the end of the third boom 23, a working tool is provided. In this embodiment, this includes a discharge hose 19 connected via a discharge port rotating joint 15. Its flow rate is controlled by an automatic valve 18 and monitored by a flow meter 13.

[0079] The perception and positioning system is used to acquire the robotic arm's own state information and the three-dimensional environment information surrounding the robotic arm. The self-state information mainly includes the angles or displacements of each joint, as well as the attitude angles of each arm and base 1. The external three-dimensional environment information includes the terrain, fixed obstacles, and moving targets within the robotic arm's workspace. The perception and positioning system is the foundation for achieving autonomous operation of the robotic arm, providing the control system 3 with all the internal and external information required for decision-making and planning. By fusing this multi-source information, the control system 3 can establish a precise understanding of itself and its environment, thereby planning a safe and efficient motion trajectory.

[0080] The control system 3 is mounted on the boom assembly 2. Specifically, its core components, such as the main controller and safety controller, are integrated into an electrical control box 31 mounted on the upper base 10. The control system 3 is electrically connected to the hydraulic system 4, the base 1, and all sensors and hydraulic actuators on the boom assembly 2 via cables. It is used to coordinate the movement of the mobile hydraulic robotic arm by combining its own status information and external environmental information. Operators can interact with the control system 3 through a remote controller 32 to issue commands and monitor the status. The electrical control box 31 is also equipped with warning lights 33 to visually display the equipment's operating status or alarm information. By placing the core components of the control system 3, especially the joint controller, on the boom assembly 2, close to the corresponding actuators and sensors, this distributed control architecture can significantly reduce signal transmission delays and interference, and improve the real-time performance and robustness of the control loop. The connections between controllers, as well as between controllers and sensors / actuators, are achieved through integrated wiring harnesses, such as the rotary drive wiring harness port 82 and the second boom cylinder wiring harness port 226. These wiring harnesses are properly arranged and protected to ensure reliability during the movement of the robotic arm. The control system 3 receives data from the sensing and positioning system, processes it through complex algorithms, and generates coordinated control commands for the movement of the base 1, the boom posture, and the operation of the end effector. These commands are then sent via cables to the corresponding drive units, such as the drive unit of the base 1 and the hydraulic actuator on the boom assembly 2, forming a complete closed loop of information perception, decision-making planning, and motion execution.

[0081] The hydraulic system 4 is mounted on the boom assembly 2, with its main power unit and auxiliary equipment such as the oil tank also installed at the rear of the upper base 10. This layout, especially the design of distributing the hydraulic power units on the boom, is a key feature of this invention. It overturns the traditional centralized oil supply mode of engineering machinery, which places a large central hydraulic pump station on the base. This distributed power supply design concept ensures that each actuator has a nearby, independent power source, thus completely solving the problems of energy loss, pressure fluctuations, and dynamic response lag caused by long-distance hydraulic pipelines. The hydraulic system 4 mainly consists of three parts: multiple hydraulic power units, multiple hydraulic actuators, and hydraulic auxiliary units.

[0082] Specifically, the hydraulic system 4 comprises multiple hydraulic power units, each corresponding one-to-one with a hydraulic actuator in the boom assembly 2. This one-to-one configuration is the core of achieving distributed drive and energy management. Each hydraulic power unit consists of a servo motor, a fixed-displacement hydraulic pump connected to the servo motor via a bell housing and coupling, an accumulator installed at the outlet of the fixed-displacement hydraulic pump, and a first pressure sensor. In this structure, the servo motor is the power source, receiving speed commands from the control system 3 and being able to adjust the output speed very precisely and quickly. The fixed-displacement hydraulic pump, such as a high-pressure gear pump, has an output flow rate proportional to the input speed. The servo motor and the fixed-displacement hydraulic pump are rigidly connected via a bell housing and coupling, forming a compact electro-hydraulic power combination. The servo motor's precise control of the fixed-displacement hydraulic pump's speed is equivalent to precise control of the hydraulic oil's output flow rate, thereby achieving "on-demand oil supply" and greatly improving energy utilization efficiency. The accumulator installed at the outlet of the fixed-displacement hydraulic pump primarily absorbs pressure fluctuations caused by pump pulsation and sudden load changes, stabilizes the system pressure, and replenishes energy when the actuator requires a large instantaneous flow rate. The first pressure sensor monitors the outlet pressure of the power unit in real time and feeds the pressure signal back to the control system 3, forming a pressure closed-loop control. Based on this feedback signal, the control system 3 dynamically adjusts the speed of the servo motor to maintain a constant outlet pressure, thereby providing a stable and reliable hydraulic energy source for the downstream hydraulic actuator.

[0083] Hydraulic system 4 also includes multiple hydraulic actuators, integrated onto the port valve blocks of the corresponding hydraulic actuators. For example... Figure 2 and Figure 4As shown, this highly integrated design aims to minimize the distance between the control valve and the actuator, thereby achieving optimal control performance. Each hydraulic actuator unit includes a servo valve, second pressure sensors mounted at the two working ports of the servo valve, and a solenoid valve for emergency locking. Taking the second boom cylinder 221 that drives the second boom 22 as an example, the components of its hydraulic actuator unit are all integrated on the second boom cylinder brake valve block 2213, which is directly mounted on the cylinder body. These components include the second boom cylinder hydraulic servo valve 2214, the second boom cylinder pressure sensor 2211, and the second boom cylinder solenoid valve 2212. The servo valve, such as the high-frequency response second boom cylinder hydraulic servo valve 2214, is a key component for achieving precise motion control. It receives a weak current signal from the joint controller and precisely controls the flow rate and direction to the two oil chambers of the second boom cylinder 221, thereby controlling the speed and direction of the actuator's movement. The second pressure sensor, such as the second boom cylinder pressure sensor 2211, is used to monitor the working pressure of the hydraulic actuator in real time. The differences in these pressure signals directly reflect the magnitude and direction of the external load borne by the actuator, providing crucial feedback information for force control, compliant control, and dynamic load compensation. Electromagnetic switching valves for emergency locking, such as the second boom cylinder electromagnetic switching valve 2212, are connected in parallel to the actuator's hydraulic circuit. Once the safety controller detects any potential safety hazard, it immediately issues a locking command to the electromagnetic switching valve, instantly locking the current posture of the robotic arm to prevent accidents due to loss of control. Similarly, the hydraulic motor 8 driving the base rotation joint 6 is also equipped with a similar hydraulic actuator, including a rotary drive hydraulic servo valve 86, a rotary drive pressure sensor 83, and a rotary drive electromagnetic switching valve 84 integrated on the rotary drive brake valve block 85.

[0084] The hydraulic system 4 also includes a hydraulic auxiliary unit, which provides support and protection for the entire hydraulic system 4. The hydraulic auxiliary unit includes an oil tank 41 with a level and temperature sensor 42, a forced cooling circulation system 43 consisting of a fan and compressor driven by a frequency converter, and a filter installed on the main return oil line. The oil tank 41 stores hydraulic oil and serves to dissipate heat and settle impurities. The level and temperature sensor 42 installed on it monitors the oil level and temperature in the tank 41 in real time, providing oil status information to the control system 3 and enabling low level alarms and high temperature warnings. The forced cooling circulation system 43 can precisely adjust the cooling power according to the instructions issued by the thermostat, ensuring that the oil temperature remains stable within the optimal operating range. The filter installed on the main return oil line removes impurities from the return oil, maintaining the cleanliness of the hydraulic oil, which is essential for the normal operation of precision hydraulic components such as servo valves.

[0085] In a more specific embodiment, the perception and positioning system is described in detail. The perception and positioning system includes an environment perception unit, a global positioning unit, an attitude perception unit, and a body perception unit. These four units work together to provide the robotic arm with comprehensive spatiotemporal perception capabilities. The environment perception unit consists of at least one LiDAR mounted on the end of the base 1 or the arm assembly 2, used for real-time scanning and building a three-dimensional point cloud map around the robotic arm. Figure 2 and Figure 3 As shown, this embodiment is equipped with multiple lidars, including a first lidar 51 and a second lidar 54 mounted on the base 1, a third lidar 34 mounted on the upper base 10, a fourth lidar 215 mounted on the first boom 21, and a fifth lidar 224 mounted on the second boom 22, achieving omnidirectional, blind-spot-free scanning of the surrounding environment. In addition, the environmental perception unit also includes multiple ultrasonic radars as supplementary sensors, such as a first ultrasonic radar 233 mounted on the third boom 23, a second ultrasonic radar 14 mounted at the boom end, and a third ultrasonic radar 227 mounted near the second boom cylinder 221, for near-range obstacle detection. An infrared camera 17 is also mounted at the boom end, providing rich image information.

[0086] The global positioning unit consists of an RTK receiver and a receiver antenna, used to obtain the absolute position of the robotic arm in the world coordinate system. For example... Figure 2 and Figure 3 As shown, this embodiment configures a first RTK11 and a second RTK12. The first RTK11 is installed at the highest point of the upper base 10, while the second RTK12 is installed on the first boom 21. Through dual-antenna positioning technology, not only can the absolute position at the centimeter level be obtained, but the heading angle of the fuselage can also be accurately measured, providing a guarantee for high-precision operations such as construction according to the drawing. The attitude sensing unit consists of multiple inertial measurement units respectively installed on the base 1 and each boom, used to measure the pitch, roll, and yaw angles of the base 1 and each boom in real time. In this embodiment, the attitude sensing unit includes a first attitude sensor 52 installed on the base 1 and a second attitude sensor 16 installed at the end of the boom. At the same time, a first tilt sensor 216 is installed on the first boom 21, and a second tilt sensor 234 is installed on the third boom 23. Together, they form a distributed attitude measurement network, which can accurately and dynamically measure the real-time attitude of each boom segment, providing key feedback information for high-precision motion control and vibration suppression.

[0087] The body sensing unit consists of a joint angle sensor coaxially mounted with each rotary joint and a cylinder stroke sensor built into each hydraulic actuator, used to measure the real-time joint pose information of each rotary joint. For example... Figure 2 and Figure 3As shown, for the rotary joints, coaxially mounted absolute angle encoders are used, including a first hollow magnetic ring angle encoder 56 for the base rotary joint 6, a second hollow magnetic ring angle encoder 214 for the first boom rotary joint 213, a third hollow magnetic ring angle encoder 223 for the second boom rotary joint 222, and a fourth hollow magnetic ring angle encoder 236 for the third boom rotary joint 235. For the pitch joint driven by a hydraulic cylinder, a high-precision stroke sensor is integrated inside the hydraulic cylinder, such as... Figure 4 The second boom cylinder stroke sensor 2215, which is built into the second boom cylinder 221, and the cylinder stroke sensors (not shown in the figure) built into the first boom cylinder 211 and the third boom cylinder 231.

[0088] In a preferred embodiment, the structural design of the joints has been optimized. Each rotary joint of the boom assembly 2 employs an integrated structure. This modular design integrates all core components related to joint function into a compact unit. The integrated structure includes: a hydraulic actuator, which is a hydraulic cylinder or hydraulic motor; an integrated valve block mounted at the hydraulic actuator port; a joint angle sensor or cylinder stroke sensor in the body sensing unit; an inertial measurement unit in the attitude sensing unit; and an integrated wiring harness connecting all components in the integrated structure to the control system 3 and integrated piping for hydraulic connections.

[0089] Specifically, as Figure 4 Taking the second boom cylinder 221 as an example, the integrated structure uses the second boom cylinder 221 as its core. The cylinder's inlet and outlet ports are directly connected to the second boom cylinder brake valve block 2213. The integrated valve block compactly mounts the second boom cylinder hydraulic servo valve 2214, the second boom cylinder pressure sensor 2211, and the second boom cylinder solenoid switch valve 2212, eliminating the need for numerous external high-pressure oil pipes. The cylinder also incorporates a second boom cylinder stroke sensor 2215. The signal and power lines of all these electronic components are integrated into a single bundle, connected to the main cable via the second boom cylinder bundle port 226. Similarly, for the base rotation joint 6, its integrated structure includes a hydraulic motor 8 as an actuator, and a rotary drive brake valve block 85 integrating a rotary drive hydraulic servo valve 86, a rotary drive pressure sensor 83, and a rotary drive solenoid switch valve 84. Its body sensing unit is a first hollow magnetic ring angle encoder 56, and its attitude sensing unit is a nearby first attitude sensor 52. The connection is achieved through the rotary drive oil pipe 81 and the rotary drive wire harness port 82.

[0090] In a further embodiment, the internal architecture of the control system 3 is described in detail. The control system 3 adopts a hierarchical, distributed control architecture, whose core components include a main controller, multiple joint controllers, a constant pressure and temperature controller, and a safety controller. The specific functions and information flow of this control architecture can be found in [reference needed]. Figure 5 The schematic diagram of the control system shown below will help us to understand it further.

[0091] The main controller is electrically connected to the sensing and positioning system and is the top-level decision-making unit of the entire control system 3. For example... Figure 5 As shown, the main controller's input terminals are connected to external obstacle detection systems, remote control systems, absolute positioning systems, and end effector attitude sensors to receive operator commands, global positioning information, and environmental perception data. Its primary task is advanced planning and coordination. It receives a 3D point cloud map from the environmental perception unit, absolute position from the global positioning unit, and complete attitude and joint information from the attitude perception unit and body perception unit. The core function of the main controller is to fuse multi-source sensor data and, through algorithms such as Kalman filtering, obtain accurate estimates of the robotic arm's own and environmental states. Then, based on the operator's input task commands or preset work processes, and according to a pre-stored multibody dynamics model, it performs motion planning that includes vibration prediction and suppression. Figure 5 In the functional division, this advanced planning function can be implemented by the motion planner module. After planning is completed, the main controller (or its internal motion controller module) generates two sets of key instructions: one set is a drive torque sequence, which is sent to each joint controller, instructing each joint to output how much force or torque. The drive torque sequence comes from motion trajectory data, which includes the corresponding velocity, acceleration, position, and torque sequence in the time dimension; the other set is a hydraulic energy supply strategy, which is sent to the constant pressure and temperature controller, instructing the entire hydraulic system on how to supply energy and manage heat.

[0092] Multiple joint controllers correspond one-to-one with each hydraulic actuator, forming the intermediate motion execution unit. The command input terminals of all joint controllers are connected to the main controller (or...) Figure 5The system connects to the motion controllers in the boom and receives motion trajectory data containing the drive torque sequence. Each joint controller is responsible for controlling only one joint. This distributed structure distributes the computational burden and improves the system's response speed and reliability. The feedback inputs of all joint controllers are connected to the corresponding body sensing units (such as angle sensors and stroke sensors) and sensors in the hydraulic actuators (such as actuator pressure sensors), ultimately forming precise pressure, speed, and position closed-loop control for each boom joint through the drive of hydraulic servo valves. A key feature is that all joint controllers are equipped with hydraulic stiffness observers for online analysis of hydraulic stiffness. Hydraulic stiffness is a measure of a joint's ability to resist external disturbances; it is related to factors such as the elastic modulus of the hydraulic oil, the oil chamber volume, and the system pressure, and is a time-varying variable. The hydraulic stiffness observers can estimate the current hydraulic stiffness value online by analyzing the pressure and displacement changes of the joints in real time. This stiffness information can be used to adjust the control gain of the joint controller to achieve adaptive control, or it can be fed back to the main controller to optimize motion planning and vibration suppression algorithms, so that the robotic arm can maintain stable and accurate performance under different loads and postures, ensuring the accuracy of motion trajectory execution.

[0093] In another implementation, by simultaneously configuring high-precision pressure sensors at the inlet and outlet of the hydraulic cylinder, the dynamic pressure difference between them can be collected and calculated in real time. This pressure difference can be accurately converted into the actual load borne by the actuator end, thereby achieving indirect measurement and continuous monitoring of the load. When the monitored load pressure exceeds the preset safety threshold range, an alarm will be triggered immediately or protective actions will be executed, effectively avoiding potential damage to the mechanical structure or hydraulic system caused by overload. Furthermore, the system can sensitively capture and analyze complex pressure difference signals caused by multiple factors, including changes in the actuator's own posture, acceleration fluctuations during movement, and real-time changes in external load. The embedded algorithm of the joint controller utilizes this high-frequency dynamic feedback data to perform real-time adaptive parameter adjustments, such as dynamically correcting the control gain or using a feedforward compensation model, to counteract the inherent nonlinear characteristics of the system and external disturbances. This mechanism enables the system to always maintain its optimal operating state, ultimately achieving precise closed-loop control of the joint motion trajectory and force output with rapid response and high robustness.

[0094] Constant pressure and temperature controller and main controller (or Figure 5 The motion controller (connected to the main controller) is the underlying energy and environmental management unit. Its primary responsibility is to receive and execute the hydraulic energy supply strategy issued by the main controller. Figure 5In the functional diagram, the controller is divided into two modules: a constant pressure controller and a constant temperature controller. The constant pressure controller receives feedback from the hydraulic pump, pressure sensor, and filter sensor, and uses closed-loop control to regulate the speed of the servo motors in each hydraulic power unit, ensuring that the output pressure of the power unit remains stable near the set value, achieving on-demand power supply. The constant temperature controller, based on feedback from the oil temperature sensor and liquid level sensor, and in conjunction with predictive thermal management commands from the main controller, actively adjusts the cooling power by controlling the air compressor and hydraulic air-cooling system, precisely controlling the oil temperature within a very small fluctuation range, thereby ensuring the thermal stability of the entire system. Furthermore, as... Figure 5 As shown, the control system also includes a dedicated motion controller. This motion controller receives movement commands from the motion controller and, combined with feedback information from the attitude sensor and relative orientation system, performs closed-loop control of the mobile chassis to achieve precise movement and positioning of the robotic arm.

[0095] Safety controller in Figure 5 The safety control system, represented in the middle, is a monitoring and protection unit with the highest priority, independent of the main controller and joint controllers. Its core task is to ensure the safety of equipment and personnel. It monitors all sensor signals, including position sensors, pressure sensors, temperature sensors, IMUs, etc. The safety controller internally sets safety thresholds and rate-of-change limits for each signal. Upon detecting any such hardware failure or abnormal state, the safety controller immediately bypasses all other controllers and directly sends a lock-up command to the solenoid valves of all hydraulic actuators. This lock-up command has higher authority than all control commands issued by other controllers in control system 3. This means that regardless of the motion commands being issued by the main controller or joint controller at the time, the safety controller's lock-up command will be enforced, reliably locking the entire robotic arm in its current position in the shortest possible time, thereby preventing accidents from occurring or escalating.

[0096] Figure 7 This is a flowchart illustrating a control method for a mobile hydraulic robotic arm in one embodiment. It should be understood that, although... Figure 7 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 7 At least some steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps. For example Figure 7 As shown, the mobile hydraulic robotic arm control method disclosed in this invention specifically includes the following steps:

[0097] S101. Use a perception and positioning system to obtain the mobile hydraulic robotic arm's own state information and the surrounding three-dimensional environment information.

[0098] In the initial stage of the control process, an integrated perception and positioning system comprehensively acquires the mobile hydraulic manipulator's own state information and a precise 3D model of its operating environment. This process is not a simple reading from a single sensor, but rather a deep fusion of multi-source information by the main controller. Specifically, the lidar in the environmental perception unit scans and generates an original 3D point cloud map of the surrounding environment; the RTK receiver in the global positioning unit provides the manipulator's centimeter-level absolute position in the world coordinate system; multiple inertial measurement units in the attitude perception unit measure the pitch, roll, and other attitude angles of the base and each arm in real time; and the joint angle sensors and cylinder stroke sensors in the body perception unit accurately report the current pose of each joint. The main controller performs spatiotemporal alignment and fusion processing on this data from different sensors with different characteristics and coordinate systems, thereby constructing a unified, accurate, and dynamically updated digital scene, providing a high-confidence decision-making basis for all subsequent planning and control tasks.

[0099] S102. The control system processes its own state information and three-dimensional environment information, and plans the final motion trajectory of the mobile hydraulic robotic arm.

[0100] After acquiring comprehensive state and environmental information, the core planning function of the control system is activated to process and calculate this information, planning a final motion trajectory that achieves both the task objective and high dynamic performance. The core of this step lies in a model-based prediction and optimization process. First, the main controller generates an initial motion trajectory that meets basic obstacle avoidance and accessibility requirements based on the task objective and the fused environmental information. Then, the main controller calls a pre-stored multibody dynamics model, which precisely includes dynamic parameters such as the mass, moment of inertia, and flexibility of each link in the boom assembly. By using the velocity and acceleration curves of the initial motion trajectory as input, the dynamic response of the robotic arm executing this trajectory is simulated in a virtual environment, thereby predicting the boom structure vibration that may be caused by high-speed movement. If the predicted vibration response exceeds a preset response threshold, the main controller initiates an optimization algorithm to minimize a comprehensive cost function by adjusting the velocity and acceleration curves of the initial motion trajectory. The goal is to generate the optimal trajectory while satisfying vibration constraints. The trajectory generated after iterative optimization is the final motion trajectory. This trajectory actively suppresses structural vibration from the planning level, ensuring the stability of the robotic arm under high-speed motion and the accuracy of end-effector positioning.

[0101] In another implementation, a high-fidelity digital twin, a millimeter-accurate 3D virtual model of the robotic arm itself, is first constructed based on its real-time state information. Simultaneously, a virtual environment model is generated using 3D environmental information acquired through devices such as LiDAR. The robotic arm's digital twin is then placed into this virtual environment model, creating an interactive simulation scene. Within this virtual space, proactive dynamic simulation and collision simulation can be performed before physical actions are executed. This means the controller can pre-calculate and evaluate multiple candidate motion trajectories, driving the virtual robotic arm with realistic kinematics and dynamics in the simulation, and detecting in real-time whether any part of the arm will interfere with or collide with any obstacle in the virtual environment. This pre-simulation eliminates all paths with collision risks and selects the optimal motion trajectory from the remaining safe paths based on optimization criteria such as highest efficiency, lowest energy consumption, or smoothest motion. This process ultimately outputs the planning results to the underlying motion controller for execution, achieving a fundamental shift from passive obstacle avoidance to active path planning, ensuring the robotic arm can achieve precise and efficient operation with zero collisions even in unknown or dynamically changing confined spaces.

[0102] S103. The control system generates a hydraulic energy supply strategy based on the final motion trajectory and instructs multiple hydraulic power units in the hydraulic system to provide power to the boom assembly according to the hydraulic energy supply strategy.

[0103] Based on the optimized final motion trajectory, the control system proactively calculates and generates a refined hydraulic energy supply strategy, instructing multiple distributed hydraulic power units in the hydraulic system to strictly follow this strategy to provide precise power for the upcoming motion. The purpose of this step is to transform from a centralized, passive energy supply mode to distributed, proactive energy management. The main controller first combines the final motion trajectory and multibody dynamics model to inversely solve for the time-varying drive torque sequence of each rotary joint throughout the entire motion. Then, through a series of nonlinear mapping models, it converts the torque demand into the instantaneous power demand curve of each hydraulic power unit. This power The calculation can be simplified to the target pressure difference across the actuator. The product of the target flow Q, i.e. Subsequently, a feedforward energy scheduling strategy is generated based on this power curve, instructing the constant pressure and temperature controller to adjust the speed of each servo motor in advance. When a high power demand is predicted, the speed is increased in advance to charge the energy storage device; during periods of low power demand, the speed is reduced to save energy. Simultaneously with this feedforward scheduling, the constant pressure and temperature controller also utilizes a first pressure sensor for real-time pressure closed-loop correction, ensuring accurate and stable energy supply. This predictive energy scheduling significantly improves the system's energy efficiency and dynamic response capabilities.

[0104] S104. By using the control system to instruct multiple hydraulic actuators in the hydraulic system, the boom assembly is driven to move along the final motion trajectory.

[0105] In this process, after the energy supply strategy is activated and power is ready, the control system ultimately instructs multiple hydraulic actuators in the hydraulic system to drive the boom assembly strictly along the final motion trajectory with high precision and stability. The main controller decomposes the final motion trajectory into target commands for each joint and sends them to their respective independent joint controllers. Each joint controller first performs preliminary closed-loop position control of its servo valve based on the target command and real-time joint pose feedback from the body sensing unit. During this process, the hydraulic stiffness observer within the joint controller is activated as a core functional module. This observer continuously analyzes the control commands of the servo valves, the real-time pressure difference measured by the second pressure sensor, and the actual minute displacements of the joints, and calculates the equivalent hydraulic stiffness of the current rotating joint online through a dynamic relationship model. Its physical meaning can be understood as the ability to resist deformation, that is... Where A is the effective working area of ​​the actuator. This represents the change in joint displacement. When the observed equivalent hydraulic stiffness decreases due to load or oil temperature changes and falls below a preset threshold, the joint controller automatically adjusts its closed-loop control parameters to adapt to the stiffness change. Simultaneously, it requests the constant pressure and temperature controller to increase the reference pressure of the power unit corresponding to the joint, thereby achieving active stiffness compensation. This adaptive stiffness control ensures that the robotic arm maintains excellent trajectory tracking accuracy under different working conditions.

[0106] In one embodiment, the process of using a control system to process its own state information and three-dimensional environmental information, and to plan the final motion trajectory of the mobile hydraulic robotic arm, includes the following steps:

[0107] The main controller integrates multi-source sensor data acquired by the environmental perception unit, global positioning unit, attitude perception unit, and body perception unit, and generates an initial motion trajectory based on the preset task objective.

[0108] The main controller calls a pre-stored multibody dynamics model containing the dynamic parameters of the boom assembly, takes the initial motion trajectory as input, and predicts the vibration response of each boom in the boom assembly when executing the initial motion trajectory.

[0109] If the predicted vibration response exceeds the preset response threshold, the velocity and acceleration curves of the initial motion trajectory are adjusted by the main controller and an optimization algorithm to generate the final motion trajectory that actively suppresses structural vibration.

[0110] In this embodiment, at the initial stage of trajectory planning, the main controller performs deep fusion of multi-source heterogeneous sensor data from the perception and positioning system to construct a unified and accurate spatiotemporal cognitive model, and based on this, generates an initial motion trajectory that meets the basic task requirements. This process first spatiotemporally aligns the lidar point cloud from the environmental perception unit, the RTK centimeter-level position from the global positioning unit, the IMU attitude angle from the attitude perception unit, and the joint encoder readings from the body perception unit. Subsequently, optimal estimation algorithms such as Extended Kalman Filter (EKF) are used to fuse these noisy measurements from different coordinate systems to estimate the precise state of the robotic arm in real time. This optimal state estimation... At each time step k, it is obtained through a prediction and update loop, and its core update step can be expressed as follows: ,in For Kalman gain, The data comes from sensor measurements. After obtaining a high-confidence state and environment model, a path planning algorithm such as A* or RRT* is invoked to generate a collision-free geometric path in 3D space. Finally, this path is converted into a joint space trajectory with time as the variable, forming an initial motion trajectory with unoptimized dynamic performance.

[0111] After obtaining the initial motion trajectory, the main controller invokes a pre-stored multibody dynamics model that accurately describes the physical characteristics of the boom assembly to predict potential structural vibrations during the execution of this trajectory. This dynamics model not only includes rigid body parameters such as the mass and inertia of each boom member but also incorporates the boom's flexibility, i.e., its resistance to bending deformation, through the finite element method or assumed modal method. The sequence of joint angles, angular velocities, and angular accelerations corresponding to the initial motion trajectory is used as input to this model. The core of the model is a set of differential equations describing the relationship between forces and motion in the system, in simplified form as follows: ,in , , These represent the system's inertia, centrifugal force, and gravity terms, respectively. and These represent the equivalent stiffness matrix of the boom and the elastic deformation caused by vibration, respectively. By solving this equation, the value of the elastic deformation under a given driving torque can be accurately calculated. Below, the end of the boom or key points undergo elastic deformation. The amplitude of the vibration response is reflected. The effect of this step is that the potential vibration risk is quantitatively grasped before the actual movement occurs, providing a precise basis for subsequent active suppression decisions.

[0112] If the predicted vibration response exceeds the preset response threshold to ensure operational accuracy, the main controller will initiate a trajectory optimization program. This program intelligently adjusts the velocity and acceleration curves of the initial motion trajectory to generate a final motion trajectory that actively suppresses structural vibration. This process is structured as a constrained optimization problem, aiming to find a trajectory with optimal overall performance while meeting vibration limitations. The trajectory itself consists of a set of parameters. By definition, the goal of an optimization algorithm is to find the optimal parameters. The goal is to optimize a specific performance metric (such as motion time or smoothness). This optimization problem can be expressed as: Solving... and satisfy the constraints. Where J is a cost function that measures the quality of the trajectory, such as minimizing the impact during motion; and w is a function that maps joint acceleration to the amplitude of vibration at the boom end. This represents the maximum permissible vibration threshold. By employing efficient numerical optimization algorithms such as Sequential Quadratic Programming (SQP), the trajectory parameters are iteratively adjusted until the optimal solution is found. The final result of this step is a smooth motion command with excellent dynamic performance, which guides the robotic arm to complete actions quickly and stably, greatly improving end-effector positioning accuracy and reducing fatigue damage to the mechanical structure.

[0113] In one embodiment, the process of using a control system to generate a hydraulic energy supply strategy based on the final motion trajectory and instructing multiple hydraulic power units in the hydraulic system to provide power to the boom assembly according to the hydraulic energy supply strategy includes the following steps:

[0114] By using the main controller and combining the final motion trajectory and multibody dynamics model, the time-varying drive torque sequence of each rotary joint during the process of realizing the final motion trajectory is calculated;

[0115] The main controller parses the drive torque sequence into the power demand curve of each hydraulic power unit.

[0116] The main controller generates a feedforward energy scheduling strategy for the servo motor in each hydraulic power unit based on the power demand curve.

[0117] The constant pressure and temperature controller executes a feedforward energy scheduling strategy. When the output power of the rotary joint exceeds the preset first power threshold, the speed of the servo motor corresponding to the rotary joint is increased in advance, and the accumulator is pressurized by a quantitative hydraulic pump. When the output power of the rotary joint is lower than the preset second power threshold, the speed of the servo motor corresponding to the rotary joint is reduced. The first power threshold is greater than the second power threshold.

[0118] During the execution of the feedforward energy scheduling strategy, the first pressure value of the first pressure sensor in each hydraulic power unit is continuously monitored by a constant pressure and temperature controller, and the speed of the servo motor is corrected in a closed loop based on the first pressure value.

[0119] In this embodiment, as the first step in energy supply planning, the main controller, combining the optimized final motion trajectory with a precise multibody dynamics model, performs inverse dynamics calculations to obtain the time-varying sequence of drive torques that each rotary joint must output to achieve the trajectory. This calculation process essentially solves the core equations describing the robotic arm's motion. The desired positions of each joint within the final motion trajectory are then determined. Expected speed and expected acceleration Substituting these known inputs into the multibody dynamics equations:

[0120]

[0121] In the equation These represent the inertia matrix, centrifugal force / Coriolis force matrix, and gravity term matrix, respectively, which change in real time with the boom attitude. Solving this equation yields the driving torque vector. This sequence accurately predicts the inertial forces, linkage coupling forces, and gravity that each joint needs to overcome throughout the entire motion, providing a precise, physics-based theoretical basis for subsequent energy and motion control.

[0122] After obtaining the joint drive torque sequence, the main controller performs an analytical process to convert it from an abstract mechanical torque domain into specific power demand curves required by each independent distributed hydraulic power unit. This analytical process involves several mapping steps. First, based on the real-time geometric parameters of the boom assembly, the drive torque of each joint is... Converted into the thrust or pull force required by the corresponding hydraulic actuator. Then, based on the effective working area A of the hydraulic actuator, this force is converted into the target pressure difference required between the actuator's inlet and outlet ports. ,Right now At the same time, the required hydraulic oil flow rate is calculated based on the target speed of the actuator. Finally, multiplying the target pressure difference by the target flow rate yields the instantaneous power demand curve of the hydraulic power unit as a function of time. The effect of this step is to break down and quantify the macroscopic joint movement requirements layer by layer into the energy flow that each underlying power source must provide, laying a data foundation for achieving on-demand and efficient energy supply.

[0123] Having accurately grasped the future power demand curve, the main controller generates a forward-looking feedforward energy scheduling strategy for each servo motor in the hydraulic power unit. The core idea of ​​this strategy is to transform passive response into active preparation; essentially, it is a time-varying speed command curve tailored to the servo motor. The generation of this command curve is based on the analysis of the power demand curve. The control algorithm predicts upcoming power peaks and troughs in advance and plans the servo motor speed accordingly. For example, before the power peak arrives, the target speed of the motor is increased in advance to drive the fixed-displacement hydraulic pump to pre-charge and store energy in the accumulator; during the foreseeable low-power phase, the target speed is actively reduced to save energy. The effect of this step is to achieve peak shaving and valley filling of energy, so that the servo motor and power source do not need to be configured according to the highest peak power, significantly improving the overall energy utilization efficiency of the system and improving the dynamic response performance of the system.

[0124] The constant pressure and temperature controller is responsible for executing the feedforward energy scheduling strategy generated by the main controller. Through a threshold-based logic, it actively adjusts the speed of the servo motor to achieve intelligent energy storage and release. During execution, it continuously compares the future power value on the power demand curve with two preset thresholds: a first power threshold and a second power threshold. When it predicts that the output power will exceed the higher first power threshold in the near future, the controller will instruct the corresponding servo motor to increase its speed, driving a fixed-displacement hydraulic pump to pressurize the accumulator at a flow rate higher than the current consumption, converting electrical energy into hydraulic energy for storage. Conversely, when it predicts that the output power will fall below the lower second power threshold, it instructs the servo motor to reduce its speed to an energy-saving baseline level. In this case, if there is motion demand, the energy released from the accumulator will be prioritized. This strategy makes the hydraulic system function like a hybrid power system, able to utilize stored energy during high demand and rest during low demand, resulting in more efficient and stable operation.

[0125] During the execution of the feedforward energy dispatch strategy, to compensate for errors caused by model inaccuracies and unexpected external disturbances, the constant pressure and temperature controller also uses a parallel closed-loop correction loop to ensure the final accuracy of energy supply. This loop continuously monitors the actual pressure reading of the first pressure sensor in each hydraulic power unit and compares it with the expected pressure setpoint corresponding to the feedforward strategy to obtain the pressure error. This error is input into a PID (proportional-integral-derivative) controller to generate a real-time compensation adjustment. Ultimately, the actual speed command of the servo motor is the sum of the speed command of the feedforward strategy and the compensation adjustment output of the PID controller. This composite control method of feedforward plus feedback utilizes both the fast response and predictive capabilities of feedforward control and the robustness and high precision characteristics of feedback control, ensuring that the power output of the hydraulic system remains stable, accurate, and reliable regardless of changes in operating conditions.

[0126] In one embodiment, the process of parsing the drive torque sequence into the power demand curve of each hydraulic power unit via the main controller includes the following steps:

[0127] The main controller acquires real-time joint pose information provided by the joint angle sensor and the cylinder stroke sensor in the body sensing unit. The real-time joint pose information includes relative rotation angle and extension length.

[0128] The main controller establishes a nonlinear mapping model from the driving torque of each rotary joint to the required output force of the corresponding hydraulic actuator based on the geometric parameters of the boom assembly.

[0129] The main controller converts the drive torque sequence into the target output force sequence required by each hydraulic actuator in real time through a nonlinear mapping model.

[0130] The main controller converts the target output force sequence into the target differential pressure sequence required by the inlet and outlet ports of each hydraulic actuator based on the effective working area of ​​each hydraulic actuator.

[0131] The main controller combines the target differential pressure sequence with the target motion speed of the hydraulic actuator to calculate the power demand curve of each hydraulic power unit over time.

[0132] In this embodiment, during the torque-to-power analysis process, the main controller first acquires the precise joint pose information of the robotic arm in real-time and at high frequency from the body sensing unit. This information forms the basis for subsequent dynamic calculations, specifically including the relative rotation angle provided by the joint angle sensor at each rotary joint, and the piston extension length provided by the cylinder stroke sensor at each pitch joint. The controller collects and synchronizes these discrete sensor readings in time, integrating them into a state vector that can completely describe the geometric configuration of the robotic arm at any given moment. After obtaining the real-time joint pose, the main controller establishes a nonlinear mapping model from the driving torque of each rotary joint to the output force required by its corresponding hydraulic actuator, based on the inherent geometric dimensional parameters of the boom assembly. This model mathematically precisely describes the conversion relationship between force and torque, which is not a simple linear proportion but dynamically changes with the boom's posture. For a joint driven by a hydraulic cylinder, the core of this model is a relationship that varies with the joint angle. Specific components of the transfer function or Jacobian matrix of the change It reflects the instantaneous changes in the actuator thrust arm. This model was pre-derived through geometric analysis and embedded in the controller's algorithm library during the robotic arm design phase. The effect of this step is to create a precise mathematical tool that can accurately translate the virtual torque acting on the joint rotation center, derived from the upper-level planning, into the actual thrust or torque that the hydraulic cylinder or motor driving the joint must generate.

[0133] Next, the main controller uses the nonlinear mapping model established in the previous step to convert the previously calculated, time-varying drive torque sequence into a target output force sequence required by each hydraulic actuator in real time. This is a continuous calculation process that occurs every millisecond during the final motion trajectory execution. The controller extracts the target torque value at a specific moment t from the drive torque sequence. And combined with the real-time joint angles acquired at the same time The mapping model can be invoked through table lookup or real-time calculation. The transformation is performed. Its core calculation can be simplified to solving... Thus, the target force that the actuator needs to output at that moment can be obtained. By performing point-by-point calculations on the entire time series, a complete output force sequence is generated. The effect of this step is to successfully transform an abstract control target (joint torque) into a specific physical quantity (thrust or tension) that can be directly generated by the physical actuator, paving the way for subsequent hydraulic parameter calculations.

[0134] After obtaining the target output force sequence required for each hydraulic actuator, the main controller further converts it into the target differential pressure sequence required between the inlet and outlet ports of each hydraulic actuator, based on the inherent physical parameters of each actuator. This conversion is based on the fundamental principle of hydrostatics, namely, the force acting on the piston equals the fluid pressure multiplied by the effective working area of ​​the piston. For a specific hydraulic cylinder, its effective working area is a constant that is determined during design and is pre-stored in the controller's parameter library. Therefore, the controller only needs to perform a simple division operation, i.e. This allows each force value in the target output force sequence to be converted into the corresponding target pressure difference value. The effect of this step is to complete the crucial transition from the mechanical domain to the hydraulic domain, transforming control commands from force to pressure. Pressure is the core variable that hydraulic systems can directly and precisely control.

[0135] In the final step, the main controller combines the target differential pressure sequence obtained in the previous step with the target speed of the hydraulic actuator to calculate the complete power demand curve of each distributed hydraulic power unit over time throughout the entire motion. This calculation first requires determining the hydraulic oil flow rate required to achieve the target speed. Based on the actuator's target speed... Based on the effective area, the instantaneous flow demand can be calculated as follows: Then, by multiplying this flow demand by the target pressure difference at the same moment, the hydraulic power that the power unit needs to output at that moment can be obtained, i.e. By performing this calculation at all points in time throughout the entire process, a precise power demand curve is generated. This curve fully predicts the energy consumption required for future motion and is the core data basis for realizing subsequent feedforward energy scheduling and efficient, proactive energy management.

[0136] In one embodiment, driving the boom assembly along a final motion trajectory by instructing multiple hydraulic actuators in the hydraulic system using the control system includes the following steps:

[0137] The main controller sends the final motion trajectory to each joint controller as the target instruction for the position control of the joint controller.

[0138] For any joint controller, preliminary closed-loop control is performed on the servo valve in the hydraulic actuator unit by using the key controller and combining the target command and real-time joint pose information.

[0139] During the initial closed-loop control process, the joint controller reads the second pressure value of the corresponding second pressure sensor and calculates the real-time differential pressure acting on the hydraulic actuator based on the second pressure value.

[0140] The joint controller utilizes a built-in hydraulic stiffness observer to analyze the dynamic relationship between the servo valve control commands, real-time differential pressure, and real-time joint pose information, and calculates the equivalent hydraulic stiffness of the current rotary joint.

[0141] When the equivalent hydraulic stiffness is lower than the preset hydraulic stiffness threshold, the joint controller adjusts the closed-loop control parameters of the initial closed-loop control according to the equivalent hydraulic stiffness, and requests the constant pressure and constant temperature controller to increase the reference pressure of the corresponding hydraulic power unit for stiffness compensation.

[0142] In this embodiment, at the beginning of the drive execution phase, the main controller sends the optimized final motion trajectory as digital instructions to the independent joint controllers distributed at each rotary joint. This process decomposes the macroscopic, collaborative motion planning into microscopic, independent joint tasks. The final motion trajectory itself is a data sequence containing timestamps, with each time point precisely defining the target position, target velocity, and even target acceleration that each joint should achieve. The main controller distributes these target instructions to the corresponding joint controllers within each control cycle via a high-speed real-time communication bus. This step effectively decouples and decentralizes the control tasks, assigning high-frequency position tracking tasks to dedicated joint controllers, significantly reducing the computational burden on the main controller, and ensuring precise time synchronization of all joint movements—a necessary prerequisite for realizing complex multi-axis linkage trajectories.

[0143] For any joint controller that receives a target command, its core task is to combine the target command with real-time joint pose information from the body sensing unit to perform preliminary closed-loop position control on the servo valve in its hydraulic actuator. This is a continuous comparison and correction process. Within each control cycle, the controller will process the target position command issued by the main controller. The actual position read back from the joint angle sensor or cylinder stroke sensor By comparison, the position error is obtained. This error is then input into a classic PID (Proportional-Integral-Derivative) controller, generating a control voltage or current command to drive the servo valve. Its calculation formula is The effect of this control law is to form a self-correcting negative feedback loop, which can automatically compensate for small external disturbances and model errors, and force the joint to accurately track the predetermined motion trajectory.

[0144] While performing initial closed-loop position control, the joint controller concurrently reads the second pressure values ​​from two second pressure sensors integrated on the hydraulic actuator. These two sensors measure the real-time operating pressure of the hydraulic actuator (such as the rodless and rod chambers of a cylinder). The controller synchronously acquires these two pressure readings and, through simple subtraction, calculates the instantaneous real-time pressure difference acting on both sides of the hydraulic actuator piston. This pressure difference directly reflects the actual driving force generated by the actuator to overcome external loads and its own inertia. This step provides the control system with a crucial force-sensing information dimension, enabling the controller to perceive the actual load during motion rather than simply blindly tracking position. This provides indispensable input data for subsequent more advanced adaptive control and state observation.

[0145] Next, the joint controller utilizes an internally configured model-based hydraulic stiffness observer to comprehensively analyze the dynamic relationship between the servo valve control commands, real-time differential pressure, and real-time joint pose information, and calculates the equivalent hydraulic stiffness of the current rotary joint online. Hydraulic stiffness is a key indicator of a joint's ability to resist deformation under external forces. This observer identifies stiffness parameters in real time using a simplified dynamic model. For example, when a servo valve command generates a small change in flow rate, causing a change in the real-time differential pressure (i.e., force),... At the same time, this also causes a slight displacement in the joint posture. Then the equivalent hydraulic stiffness This dynamic response relationship can be used to estimate, that is... This observer continuously performs calculations and outputs a real-time changing stiffness value. The effect of this step is to enable the control system to have self-diagnostic capabilities, allowing it to understand the dynamic changes in its own mechanical characteristics in real time, such as whether the system becomes "softer" or "harder" due to increased oil temperature or changes in attitude.

[0146] When the equivalent hydraulic stiffness value calculated by the hydraulic stiffness observer decreases due to changes in operating conditions and falls below a preset hydraulic stiffness threshold to ensure performance, the joint controller immediately activates a dual compensation mechanism. First, at the software level, the controller automatically adjusts its PID closed-loop control parameters based on the current equivalent hydraulic stiffness using a preset gain scheduling table. For example, it reduces the proportional gain and increases the derivative gain to adapt to the softened system and suppress potential oscillations. Second, at the hardware level, the controller immediately sends a request command to the constant pressure and temperature controller, requesting an increase in the reference system pressure of the hydraulic power unit corresponding to the joint. Higher system pressure directly and physically increases the rigidity of the hydraulic oil. This coordinated hardware and software active stiffness compensation ensures that the robotic arm maintains high rigidity and high-precision dynamic response characteristics under various loads and environments, greatly enhancing the system's robustness and operational performance.

[0147] In one embodiment, the method further includes the following steps:

[0148] The safety controller monitors in real time and in parallel the readings of all sensors in the sensing and positioning system and the hydraulic system, as well as the actual movement trajectory of the mobile hydraulic robotic arm.

[0149] If the value of any sensor exceeds the preset danger threshold or the deviation between the actual movement trajectory and the final movement trajectory exceeds the preset deviation threshold, the safety controller will send a locking command with the highest authority to the solenoid valves of all hydraulic actuators on the boom assembly.

[0150] When the solenoid valve receives the lock-up command, it locks the oil circuits of all hydraulic actuators to freeze the current state of the boom assembly.

[0151] In this embodiment, throughout the entire control process, an independent safety controller continuously monitors all critical states of the mobile hydraulic robotic arm in real time and in parallel. This monitoring task is multi-dimensional. First, it continuously scans the readings of all sensors in the sensing and positioning system and the hydraulic system, including but not limited to pressure, temperature, fluid level, joint angle, and cylinder stroke, ensuring that these values ​​are all within the preset safe operating range. Second, it dynamically calculates the deviation between the final motion trajectory command issued by the main controller and the actual motion trajectory fed back by the body sensing unit. This trajectory deviation... The calculation can be simplified to the desired position of the robotic arm end effector at each time t. With actual location The Euclidean distance between them, i.e. The effect of implementing this dual monitoring mechanism is to establish a comprehensive safety defense line independent of the main control loop, capable of simultaneously detecting faults in local components and loss of control of overall movement.

[0152] Once the monitoring system detects any predefined hazardous condition, the safety controller immediately and unconditionally triggers an emergency braking procedure with the highest execution authority. This triggering mechanism is based on a strict set of logical judgments. If any monitored sensor reading... It exceeded its preset danger threshold range. Or the calculated trajectory deviation Exceeded the preset deviation threshold A logical OR gate will immediately output a trigger signal. This trigger condition R can be expressed as... ,in This represents the out-of-limit condition for sensor i. This represents an out-of-limit condition indicating trajectory deviation. This means that any single failure is sufficient to trigger a safety response. Once triggered, the safety controller immediately generates a digital locking command and simultaneously broadcasts it via a dedicated, highest-priority communication link to all solenoid valves deployed within the hydraulic actuators of the boom assembly. This command has higher authority than any motion commands issued by the main controller and joint controllers, ensuring absolute priority and enforceability of safety measures.

[0153] When all the solenoid valves distributed throughout the boom assembly receive a lock-up command from the safety controller, they instantly execute a physical lock-up action, cutting off and locking the oil circuits of all hydraulic actuators, thus freezing the current state of the entire boom assembly within milliseconds. These solenoid valves are 2-position 2-way or 2-position 3-way fast-response valves, which do not interfere with the main oil circuit during normal operation. Upon receiving the electrical excitation signal of the lock-up command, their internal valve cores immediately switch positions, physically sealing the oil ports connecting the two working oil chambers of the hydraulic actuators (such as cylinders or motors). This seals off the hydraulic oil in the chambers, and due to the extremely low compressibility of hydraulic oil, an immovable rigid oil column is formed inside and outside the actuator. This action occurs simultaneously at all joints, and its ultimate effect is to instantly and reliably lock the entire robotic arm in the posture at which the safety command was triggered, effectively preventing boom collapse, impact, or any other unforeseen dangerous movements caused by loss of control.

[0154] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0155] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A mobile hydraulic robotic arm, characterized in that, The mobile hydraulic robotic arm includes a boom assembly, a base, a sensing and positioning system, a hydraulic system, and a control system; The base is a movable chassis with an independent drive device; The boom assembly is mounted on the base and consists of at least two booms connected in series via rotary joints, with each rotary joint integrating a hydraulic actuator for driving. The perception and positioning system is used to acquire the robotic arm's own state information and the three-dimensional environment information around the robotic arm. The control system is mounted on the boom assembly and is electrically connected to the hydraulic system, the base, and all sensors and hydraulic actuators on the boom assembly via cables. It is used to coordinate the movement of the mobile hydraulic robotic arm by combining its own status information and external environmental information. The control system includes: The main controller is electrically connected to the sensing and positioning system and is used to fuse multi-source sensor data and perform motion planning including vibration prediction and suppression based on a pre-stored multibody dynamics model, generating a drive torque sequence and hydraulic energy supply strategy. Multiple joint controllers correspond one-to-one with each hydraulic actuator. The command input terminals of all joint controllers are connected to the main controller and used to receive the drive torque sequence. The feedback input terminals of all joint controllers are connected to the sensors in the corresponding body sensing unit and hydraulic actuator unit. All joint controllers are equipped with a hydraulic stiffness observer for online analysis of hydraulic stiffness. The constant pressure and temperature controller is connected to the main controller and is used to receive and execute the hydraulic energy supply strategy, control the speed of the servo motor in each hydraulic power unit in a closed loop, and adjust the cooling power according to the predictive thermal management instructions of the main controller. The safety controller monitors all sensor signals and sends a lock-up command to the solenoid valves of all hydraulic actuators when a hardware fault is detected. The lock-up command has higher authority than the control commands issued by all other controllers in the control system. The hydraulic system is mounted on the boom assembly, and the hydraulic system includes: Multiple hydraulic power units correspond one-to-one with each hydraulic actuator of the boom assembly. Each hydraulic power unit consists of a servo motor, a fixed-displacement hydraulic pump connected to the servo motor via a bell-shaped cover and a coupling, an accumulator installed at the outlet of the fixed-displacement hydraulic pump, and a first pressure sensor. Multiple hydraulic actuators are integrated on the oil port valve block of the corresponding hydraulic actuator. Each hydraulic actuator includes a servo valve, a second pressure sensor installed at each of the two working oil ports of the servo valve, and an electromagnetic switch valve for emergency locking. The hydraulic auxiliary unit includes an oil tank with a liquid level and temperature sensor, a forced refrigeration cycle system consisting of a fan and compressor driven by a frequency converter, and a filter installed on the main return oil line.

2. The mobile hydraulic robotic arm according to claim 1, characterized in that, The sensing and positioning system includes: The environmental perception unit consists of at least one lidar installed at the base or end of the boom assembly, used to scan and build a three-dimensional point cloud map around the robotic arm in real time. The global positioning unit consists of an RTK receiver and a receiver antenna mounted on the boom assembly, used to obtain the absolute position of the robotic arm in the world coordinate system; The attitude sensing unit consists of multiple inertial measurement units installed on the base and each boom, and is used to measure the pitch, roll and yaw angles of the base and each boom in real time. The body sensing unit consists of a joint angle sensor coaxially mounted with each rotary joint and a cylinder stroke sensor built into each hydraulic actuator, used to measure the real-time joint pose information of each rotary joint.

3. The mobile hydraulic robotic arm according to claim 2, characterized in that, Each rotary joint of the boom assembly employs an integrated structure, which includes: Hydraulic actuators are either hydraulic cylinders or hydraulic motors; An integrated valve block is installed at the oil port of the hydraulic actuator. The servo valve, the second pressure sensor, and the solenoid switch valve are all installed on the integrated valve block. One of the joint angle sensors or hydraulic cylinder stroke sensors in the body sensing unit; An inertial measurement unit within the attitude sensing unit; In addition, integrated wiring harnesses that connect all components in the integrated structure to the control system and integrated piping for hydraulic connections.

4. A control method for a mobile hydraulic robotic arm, characterized in that, The method, applied to the mobile hydraulic robotic arm according to any one of claims 1 to 3, comprises the following steps: The sensing and positioning system is used to obtain the mobile hydraulic robotic arm's own state information and the surrounding three-dimensional environment information; The control system processes its own state information and three-dimensional environment information, and plans the final motion trajectory of the mobile hydraulic robotic arm. The control system generates a hydraulic energy supply strategy based on the final motion trajectory and instructs multiple hydraulic power units in the hydraulic system to provide power to the boom assembly according to the hydraulic energy supply strategy. The main controller sends the final motion trajectory to each joint controller as the target instruction for the position control of the joint controller. For any joint controller, preliminary closed-loop control is performed on the servo valve in the hydraulic actuator unit by using the key controller and combining the target command and real-time joint pose information. During the initial closed-loop control process, the joint controller reads the second pressure value of the corresponding second pressure sensor and calculates the real-time differential pressure acting on the hydraulic actuator based on the second pressure value. The joint controller utilizes a built-in hydraulic stiffness observer to analyze the dynamic relationship between the servo valve control commands, real-time differential pressure, and real-time joint pose information, and calculates the equivalent hydraulic stiffness of the current rotary joint. When the equivalent hydraulic stiffness is lower than the preset hydraulic stiffness threshold, the joint controller adjusts the closed-loop control parameters of the initial closed-loop control according to the equivalent hydraulic stiffness, and requests the constant pressure and constant temperature controller to increase the reference pressure of the corresponding hydraulic power unit for stiffness compensation.

5. The control method for a mobile hydraulic robotic arm according to claim 4, characterized in that, The process of using the control system to process its own state information and three-dimensional environment information, and to plan the final motion trajectory of the mobile hydraulic robotic arm, includes the following steps: The main controller integrates multi-source sensor data acquired by the environmental perception unit, global positioning unit, attitude perception unit, and body perception unit, and generates an initial motion trajectory based on the preset task objective. The main controller calls a pre-stored multibody dynamics model containing the dynamic parameters of the boom assembly, takes the initial motion trajectory as input, and predicts the vibration response of each boom in the boom assembly when executing the initial motion trajectory. If the predicted vibration response exceeds the preset response threshold, the velocity and acceleration curves of the initial motion trajectory are adjusted by the main controller and an optimization algorithm to generate the final motion trajectory that actively suppresses structural vibration.

6. The control method for a mobile hydraulic robotic arm according to claim 5, characterized in that, The process of using the control system to generate a hydraulic energy supply strategy based on the final motion trajectory and instructing multiple hydraulic power units in the hydraulic system to provide power to the boom assembly according to the hydraulic energy supply strategy includes the following steps: By using the main controller and combining the final motion trajectory and multibody dynamics model, the time-varying drive torque sequence of each rotary joint during the process of realizing the final motion trajectory is calculated; The main controller parses the drive torque sequence into the power demand curve of each hydraulic power unit. The main controller generates a feedforward energy scheduling strategy for the servo motor in each hydraulic power unit based on the power demand curve. The constant pressure and temperature controller executes a feedforward energy scheduling strategy. When the output power of the rotary joint exceeds the preset first power threshold, the speed of the servo motor corresponding to the rotary joint is increased in advance, and the accumulator is pressurized by a quantitative hydraulic pump. When the output power of the rotary joint is lower than the preset second power threshold, the speed of the servo motor corresponding to the rotary joint is reduced. The first power threshold is greater than the second power threshold. During the execution of the feedforward energy scheduling strategy, the first pressure value of the first pressure sensor in each hydraulic power unit is continuously monitored by a constant pressure and temperature controller, and the speed of the servo motor is corrected in a closed loop based on the first pressure value.

7. The control method for a mobile hydraulic robotic arm according to claim 6, characterized in that, The process of parsing the drive torque sequence into the power demand curve of each hydraulic power unit via the main controller includes the following steps: The main controller acquires real-time joint pose information provided by the joint angle sensor and the cylinder stroke sensor in the body sensing unit. The real-time joint pose information includes relative rotation angle and extension length. The main controller establishes a nonlinear mapping model from the driving torque of each rotary joint to the required output force of the corresponding hydraulic actuator based on the geometric parameters of the boom assembly. The main controller converts the drive torque sequence into the target output force sequence required by each hydraulic actuator in real time through a nonlinear mapping model. The main controller converts the target output force sequence into the target differential pressure sequence required by the inlet and outlet ports of each hydraulic actuator based on the effective working area of ​​each hydraulic actuator. The main controller combines the target differential pressure sequence with the target motion speed of the hydraulic actuator to calculate the power demand curve of each hydraulic power unit over time.

8. The control method for a mobile hydraulic robotic arm according to claim 4, characterized in that, The method further includes the following steps: The safety controller monitors in real time and in parallel the readings of all sensors in the sensing and positioning system and the hydraulic system, as well as the actual movement trajectory of the mobile hydraulic robotic arm. If the value of any sensor exceeds the preset danger threshold or the deviation between the actual movement trajectory and the final movement trajectory exceeds the preset deviation threshold, the safety controller will send a locking command with the highest authority to the solenoid valves of all hydraulic actuators on the boom assembly. When the solenoid valve receives the lock-up command, it locks the oil circuits of all hydraulic actuators to freeze the current state of the boom assembly.

Images