Hydraulic mechanical arm solving method and system

Abstract

The application provides a kind of water mechanical arm solving method and system, it is related to water conservancy engineering intelligent equipment technical field, including the following specific steps: through multi-sensor fusion obtains environmental data and the initial state of mechanical arm;Kinematics model coupled with dynamic water power is established;Solving is carried out using hybrid inverse kinematics solving architecture;Through pre-compensation and real-time error correction, fluctuation disturbance is inhibited.The application establishes a motion model for the bearing platform by collecting data, introduces the motion trend output by the model into the D-H parameter model and makes corrections;Using the corrected model, the control command is obtained by inverse kinematics solving;PID control is performed during the operation of the mechanical arm to adjust the motion state of the mechanical arm.The deviation of the pose of the end of the mechanical arm and the three-dimensional position of the target object is collected, and the current water flow speed and the position of the mechanical arm are input, and a new solution is output to control the mechanical arm to move steadily towards the target object and complete the specified action.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent equipment for water conservancy projects, and more specifically, to a method and system for solving a water conservancy mechanical arm. BACKGROUND

[0002] Water conservancy projects are projects built to control and distribute surface water and groundwater in nature to achieve the purpose of eliminating harm and benefiting. It is also known as water project. Water is an indispensable and precious resource for human production and life, but its natural state does not fully meet human needs. Only by building water conservancy projects can water flow be controlled to prevent flood disasters and water can be regulated and distributed to meet the needs of people's life and production for water resources. Water conservancy projects need to build different types of hydraulic structures such as dams, dikes, spillways, sluices, intake structures, channels, waterways, raftways, and fishways to achieve their goals.

[0003] River dredging is a type of water conservancy project, which usually removes silt deposited at the river bottom by mechanical equipment to dredge. There are several common methods for river dredging: 1. Dry dredging;

[0004] Advantages: complete dredging, easy to control dredging depth, high sludge concentration, low transportation cost, and relatively low engineering cost. Disadvantages: need to build cofferdams for drainage, have some impact on the safety of the two banks' revetments, may cause damage to existing engineering facilities on both banks during construction, prone to secondary pollution, not suitable for construction during the rainy season and for rivers that should not be interrupted; 2. Semi-dry dredging; Advantages: complete dredging, easy to operate, easy to pass through bridges and other river obstacles, using pipeline to transport slurry can avoid secondary pollution during transportation and reduce interference with residents on both sides of the river. Disadvantages: high power consumption and high labor costs, also not suitable for construction during the rainy season and for rivers that should not be interrupted; 3. Small-scale dredging machine; Advantages: can complete the dredging, transportation, discharge, and treatment of slurry in one operation, continuous operation, high production efficiency, low cost, smooth excavation working surface, easy to control the depth of the excavation slope, and good construction quality. Disadvantages: need to lay sludge pipelines, have some impact on river navigation, poor self-propulsion, limited dredging depth, sensitive to water flow and waves, prone to bottom mud dispersion, and need to set up a protective cover for control.

[0005] The above several dredging methods have various shortcomings; dry and semi-dry dredging is not suitable for river channels that are not suitable for flow interruption; the cutter suction dredger has poor stability and is sensitive to waves; and regardless of which method is used, manual operation of mechanical equipment is required, and when operating mechanical equipment on the water surface, dredging workers have to work on a muddy and slippery riverbed, facing multiple threats such as drowning and inhaling harmful substances; with the development of artificial intelligence and the robotics industry, it has become possible to use a mechanical arm to replace manual operation for dredging. However, in the prior art, the mechanical arm cannot work autonomously, and it is greatly affected by environmental factors, for example, during the process of the mechanical arm dredging on the carrying platform, the center of gravity of the platform changes, causing the entire platform to fluctuate periodically; and since the mechanical arm is fixed on the carrying platform, the position of the end of the mechanical arm fluctuates greatly at this time, resulting in insufficient accuracy. Therefore, how to kinematically solve the water conservancy mechanical arm in a fluctuating environment to improve the accuracy of the mechanical arm has become a technical problem to be solved. SUMMARY

[0006] In order to solve the above technical problems, the present application is proposed. The present application provides a water conservancy mechanical arm solving method and system.

[0007] According to one aspect of the present application, a water conservancy mechanical arm solving method is provided, comprising the following specific steps:

[0008] S1: obtaining environmental data and the initial state of the mechanical arm through multi-sensor fusion;

[0009] S2: establishing a kinematic model coupled with dynamic water power;

[0010] S3: solving by using a hybrid inverse kinematics solving architecture;

[0011] S4: suppressing fluctuation interference through pre-compensation and real-time error correction.

[0012] Further, in step S1, sensors are used to collect water flow velocity, carrying platform fluctuation data, mechanical arm joint angle, and end pose data.

[0013] Further, in step S1, time calibration is performed to time-match the environmental data determined by the sensor parameters and the state data of the mechanical arm.

[0014] Further, in step S2, the water power disturbance is converted into an equivalent joint offset, and the standard D-H parameter model is corrected.

[0015] Further, in step S3, constraint conditions are set according to the environmental data and the pose of the mechanical arm; and an initial feasible solution is quickly generated by combining the analytical method.

[0016] Further, the feasible solution is used as a control instruction and input to a control end of the mechanical arm; and the mechanical arm is controlled to operate.

[0017] Further, in step S4, real-time error correction is performed on the operating mechanical arm to improve the accuracy of the end pose of the mechanical arm.

[0018] The second aspect of the present application provides a hydraulic mechanical arm solving system, which uses the above method to solve the mechanical arm, and comprises a data acquisition unit, a calculation processing unit and a control execution unit.

[0019] The data acquisition unit is used to acquire environmental data and initial state data of the mechanical arm.

[0020] The calculation processing unit uses the acquired environmental data and initial state data of the mechanical arm as input and uses the trained model to perform solving calculation.

[0021] The control execution unit controls the mechanical arm to perform corresponding actions according to the obtained solution, and performs real-time error correction based on PID during the movement.

[0022] Further, the data acquisition unit comprises an ultrasonic sludge level meter, a water flow sensor, a first inertial measurement unit, a second inertial measurement unit, a joint angle measurement sensor and a joint torque sensor.

[0023] The ultrasonic sludge level meter is installed at the bottom of the bearing platform below the liquid surface and emits ultrasonic signals to detect the height of the sludge layer at the water bottom.

[0024] The water flow sensor is installed at the bottom of the bearing platform to detect the water flow rate.

[0025] The first inertial measurement unit is installed on the bearing platform to detect the pose change of the bearing platform itself.

[0026] The second inertial measurement unit is installed on the mechanical arm to detect the pose change of the end of the mechanical arm.

[0027] The joint angle measurement sensor is a Hall sensor used to detect the angle of each joint of the mechanical arm.

[0028] The joint torque sensor is a sheet type torque sensor used to detect the output torque of the joint.

[0029] The third aspect of the present application provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above hydraulic mechanical arm solving method when executing the computer program.

[0030] Compared with the prior art, the present application establishes a motion model for the bearing platform by collecting data, introduces the motion trend output by the model into the D-H parameter model, and corrects it; at the same time, the constraint condition is set, and the control command is obtained by using the corrected model through inverse kinematics solution; PID control is performed in the process of controlling the operation of the mechanical arm, and the motion state of the mechanical arm is adjusted. The deviation of the pose of the end of the mechanical arm and the three-dimensional position of the target object is collected, the current water flow speed and the position of the mechanical arm are taken as inputs, and a new solution is output to control the mechanical arm to move steadily towards the target object and complete the specified action. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort. In the drawings:

[0032] Figure 1 The flow chart of the water mechanical arm solving method according to the embodiment of the present application.

[0033] Figure 2 The structural block diagram of the water mechanical arm solving system according to the embodiment of the present application.

[0034] Figure 3 The structural schematic diagram of the computer system of the electronic device of the embodiment of the present application. DETAILED DESCRIPTION

[0035] In the following, the example embodiments according to the present application will be described in detail with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described here.

[0036] Embodiment 1

[0037] As described in the above background, in the process of dredging by the mechanical arm on the bearing platform, the center of gravity of the platform changes, causing the whole platform to fluctuate periodically; and since the mechanical arm is fixed on the bearing platform, the position of the end of the mechanical arm is superimposed with its own motion and the fluctuation of the platform, resulting in a large displacement and a problem of insufficient precision. Therefore, how to kinematically solve the water mechanical arm in the fluctuating environment to improve the precision of the mechanical arm has become a technical problem to be solved.

[0038] As shown in Figure 1 The present embodiment provides a water mechanical arm solving method, which comprises the following specific steps:

[0039] S1: Obtain the environment data and the initial state of the robot arm through multi-sensor fusion; In step S1, the water flow velocity, the bearing platform fluctuation data, the joint angle of the robot arm and the end position data are collected by sensors; The motion model of the bearing platform is established by the collected water flow velocity and bearing platform fluctuation data; Through actual experiments, different water flow velocities and bearing platform fluctuation data are collected, the original data is processed, and the function equation of water flow velocity and bearing platform fluctuation is established; Then adjust the joint angle of the robot arm and the end position to determine the influence of the spatial position change of the robot arm on the bearing platform fluctuation, so as to reduce the error;

[0040] Specifically, the experimental robot arm is installed on the bearing platform and moved to the water surface of the experimental area; The acoustic Doppler current profiler is used to measure the water flow velocity of the experimental area; The data of water flow velocity in the range of 0.1-2m / s is collected (water flow velocity exceeding 2m / s has safety hazards), and the influence of water flow velocity on the bearing platform is determined; Then adjust the robot arm to different positions, simulate the action process of the robot arm and superimpose the influence of water flow velocity on the bearing platform, and establish the motion model of the bearing platform; By inputting the water flow velocity and the position of the robot arm, the spatial position change of the platform can be output by the motion model of the bearing platform, the change of the bearing platform relative to the starting position is determined, and the motion state of the bearing platform in three-dimensional space is determined; The measured data is learned in depth with the output data of the motion model to improve the accuracy of the output of the motion model;

[0041] Step S1 also needs to be time calibrated, and the environment data determined by the sensor parameters and the state data of the robot arm are time matched. For sensor data with different sampling frequencies, spline interpolation method is used for time alignment.

[0042] S2: Establish a kinematic model coupled with dynamic water power; In step S2, the water power disturbance is converted into equivalent joint offset, and the standard D-H parameter model is corrected. In this embodiment, the D-H parameter model is a standardized method for describing the geometric relationship between the links and joints of the serial robot arm, which uniquely determines the transformation relationship of the adjacent link coordinate system through four parameters. Each joint corresponds to four parameters: link length ai, link torsion angle αi, joint offset di, and joint angle θi. Since the D-H parameter model is well known in the art, it will not be described in detail here; In this embodiment, the output of the bearing platform motion model obtained in step S1 is superimposed into the D-H parameter model to construct a dynamic water power corrected D-H model; Specifically as follows:

[0043] In the fluctuating environment, the disturbance of the bearing platform is quantified as equivalent D-H parameter correction:

[0044] End effector offset caused by the action of the bearing platform Δp = [Δx, Δy, Δz] T Decompose to each joint by Jacobian matrix: Δq = J −1 (q) Δp;

[0045] Correct joint angle: θi ′ = θi+ Δqi

[0046] Correct transformation matrix:

[0047]

[0048] In the above formula, Δp is the end effector offset caused by the action of the bearing platform; Δq is the equivalent angle offset of each joint; J(q) is the Jacobian matrix of the robot arm, θi ′ is the corrected joint angle; Tt is the corrected transformation matrix.

[0049] In this embodiment, by modifying the existing D-H model, the end effector offset caused by the movement of the bearing platform is introduced into the D-H model; in the experiment, the laser tracking positioner can also be used to measure the end pose, and the D-H parameter error is corrected in reverse, to further improve the accuracy of the modified model.

[0050] S3: solve by using a hybrid inverse kinematics solving architecture; in step S3, set constraint conditions according to the environmental data and the pose of the robot arm; combine the analytical method to quickly generate an initial feasible solution; use the feasible solution as a control instruction and input it to the control end of the robot arm; control the robot arm to run.

[0051] Inverse kinematics solving is an important concept in kinematics, which mainly studies how to calculate the joint angle or motion parameter according to the target position and attitude of the end effector. It is the inverse process of forward kinematics; inverse kinematics is to solve the joint angle or motion parameter when the target position and attitude of the end effector are known.

[0052] In this embodiment, the constraints are set for the robot arm itself to improve the solving speed; specifically: (1) set the constraint range according to the physical parameters of the robot arm itself, such as link length, number of joints, joint angle, etc., and set the boundary condition with 80% of the maximum adjustment amount as the target; (2) set the physical boundary condition according to the boundary range of the specific working scene, for example, there is a collision target in the work area, and the boundary area is drawn within 1m of the collision target to avoid collision between the robot arm and the obstacle; (3) energy consumption constraint; upper limit of joint torque square sum: where i is the number of joints, Determined by the hydraulic system pressure threshold. By setting the above three boundary conditions, solve; first with target 1 and 2 to solve, in a large number of solutions with the minimum value of target 3 as the initial solution output. Using the feasible solution as the control command, input to the control end of the robot arm; control the robot arm to run, in the process of the robot arm running, according to the pose change of the robot arm, real-time correction is carried out.

[0053] S4: suppress fluctuation disturbance by pre-compensation and real-time error correction; in step S4, real-time error correction is performed on the running robot arm to improve the accuracy of the end pose of the robot arm.

[0054] In this embodiment, according to the motion model established for the bearing platform in step 1, when the robot arm needs to be controlled to move, the current water flow speed and the initial state of the robot arm are detected and sent as inputs to the bearing platform motion model, and the pose change of the bearing platform caused by the action of the robot arm is output;

[0055] The pose change is input to the kinematics model coupled with dynamic water power in step S2, and inverse kinematics is solved by the modified D-H parameter model; the initial solution is obtained by setting the target constraints in step S3; the initial solution is input as the control quantity of the robot arm to control the running of the robot arm; in this embodiment, the purpose of pre-compensation is achieved by the modified D-H parameter model when solving, the compensation quantity is input in advance, and the error of the robot arm end is reduced to improve the accuracy; when the robot arm gets the control command to move, the motion state of the bearing platform and the robot arm is detected by the sensor, and the motion state of the bearing platform is compared with the estimated state output by the bearing platform motion model, when the amplitude of the actual motion state of the bearing platform and the estimated state exists more than 10% action error, then start PID control, adjust the motion state of the robot arm. The deviation of the pose of the robot arm end and the three-dimensional position of the target object is collected, the current water flow speed and the position of the robot arm are input, steps S1-S3 are repeated, and a new solution is output to control the robot arm to move steadily towards the target object and complete the specified action.

[0056] This embodiment improves the solving speed by pre-compensation and setting constraints based on the simulation model established by analyzing the fluctuating running data of the robot arm on the platform; and adjusts the pose of the robot arm end based on PID adaptive control to adapt to the motion state in fluctuating environment and improve the running accuracy of the robot arm. Through the automatic operation of the robot arm, the dependence on manual operation for river dredging is reduced, and the workers are avoided from working in the muddy and slippery riverbed, facing multiple threats such as drowning and inhaling harmful substances.

[0057] The following uses a specific case to introduce the scheme of this embodiment in detail

[0058] A company carries out river dredging operation in a tributary of the Yangtze River; the water flow speed in the operation area is 0.5-1.8 m / s, which is not suitable for cofferdam dry dredging or semi-dry dredging; therefore, a mechanical arm with a bucket is installed on a carrying platform to carry out dredging work on the river; the carrying platform is 10 m long and 8 m wide; the mechanical arm is installed at the middle position of the carrying platform, and the driving device and control system are installed at the rear end of the carrying platform, which is the forbidden area for the mechanical arm; the right side of the mechanical arm is hung on the sludge transport vehicle; during operation, the mechanical arm needs to be controlled to extend into the water bottom to dig up the sludge and transfer it to the sludge transport vehicle; the specific steps are as follows:

[0059] First, determine the target working area, determine the sludge depth of the target working area through the ultrasonic sludge level meter, and determine the working range and working route, and determine the depth of the sludge to be dredged;

[0060] Then, obtain environmental data and the initial state of the mechanical arm through multi-sensor fusion; use sensors to collect water flow speed, carrying platform fluctuation data, mechanical arm joint angle and end pose data; the water flow speed and the initial state of the mechanical arm collected on site are input into the established carrying platform motion model; the current water flow speed is 1 m / s; the pose of the mechanical arm is established according to the current angle of each joint, and the three-dimensional space coordinates of the end of the mechanical arm are input into the motion model in the form of three-dimensional coordinates; the carrying platform motion model outputs the estimated carrying platform pose change;

[0061] Then, the carrying platform pose change caused by the movement of the mechanical arm needs to be converted to make the water dynamic disturbance equivalent to the joint offset, and the standard D-H parameter model is corrected; the specific steps are as follows:

[0062] In the fluctuating environment, the disturbance of the carrying platform is quantified as the equivalent D-H parameter correction:

[0063] The end offset Δp caused by the action of the carrying platform is [Δx, Δy, Δz] T , which is decomposed into each joint through Jacobian matrix: Δq = J −1 (q)Δp;

[0064] Correct the joint angle: θi ′ = θi+Δqi

[0065] Correct the transformation matrix:

[0066]

[0067] In the above formula, Δp is the end offset caused by the action of the carrying platform; Δq is the equivalent angle offset of each joint; J(q) is the Jacobian matrix of the mechanical arm, θi ′ is the corrected joint angle; Tt is the corrected transformation matrix.

[0068] In the embodiment, the end displacement caused by the movement of the bearing platform is introduced into the D-H model by modifying the existing D-H model, and the parameter error obtained from the experimental data is supplemented into the modified model to further improve the accuracy of the modified model.

[0069] The mixed inverse kinematics solving architecture is used for solving; the constraint conditions are set according to the environmental data and the pose of the robot arm; the initial feasible solution is quickly generated in combination with the analytical method; the feasible solution is used as the control command and input to the control end of the robot arm; and the robot arm is controlled to run.

[0070] For example, in the embodiment, the lengths of the links of the robot arm are 2.0 m, 3.5 m and 5 m respectively, the joints run between -90° and 120°, and the obstacle avoidance constraint condition is set to 1 m; the rear of the bearing platform is set as a forbidden zone; and the robot arm is prevented from moving to this place.

[0071] The constraint conditions are set for the robot arm itself to improve the solving speed; first, the targets 1 and 2 are solved, and the minimum value of the target 3 is used as the initial solution output among numerous solutions; the feasible solution is used as the control command and input to the control end of the robot arm to realize the control and operation of the robot arm under the minimum energy consumption; and the real-time correction is performed according to the pose change of the robot arm during the operation of the robot arm.

[0072] The fluctuation disturbance is suppressed by pre-compensation and real-time error correction; the real-time error correction is performed on the running robot arm to improve the accuracy of the pose of the end of the robot arm.

[0073] In the embodiment, according to the movement model established by the bearing platform, when the movement of the robot arm needs to be controlled, the current water flow velocity and the initial state of the robot arm are detected and sent as inputs to the bearing platform movement model, and the pose change of the bearing platform caused by the action of the robot arm under the action is output;

[0074] The pose change is input and inverse kinematics is solved by the modified D-H parameter model; the boundary conditions and target constraints are set according to the foregoing actual limitations, and the initial solution is obtained; the initial solution is used as the control amount of the robot arm and input to the control end to control the operation of the robot arm;

[0075] In this embodiment, by using the modified D-H parameter model to solve, the purpose of pre-compensation is achieved, the compensation amount is input in advance, the error of the end of the mechanical arm is reduced to improve the precision; when the mechanical arm gets the control instruction to move, the sensor detects the motion state of the bearing platform and the mechanical arm, and compares the motion state of the bearing platform with the estimated state output by the bearing platform motion model, and when the amplitude of the actual motion state of the bearing platform and the estimated state exists more than 10% action error, the PID control is started, and the motion state of the mechanical arm is adjusted. The deviation of the pose of the end of the mechanical arm and the three-dimensional position of the target object is collected, the current water flow speed and the position of the mechanical arm are used as inputs, and a new solution is output to control the mechanical arm to move steadily towards the target object and complete the specified action.

[0076] Through actual test, it is found that when the target area is dredged, the precision error is less than 5cm, which meets the target requirement. Through this scheme, the error generated when the mechanical arm operates in a fluctuating environment is solved, and the precision is improved; the intelligent control mechanical arm is introduced into the river dredging operation, which reduces the labor intensity of personnel, improves the efficiency and reduces the danger.

[0077] Embodiment 2

[0078] As shown in Figure 2 , the present embodiment provides a hydraulic mechanical arm solving system, which uses the method in embodiment 1 to solve the mechanical arm, including a data acquisition unit, a calculation processing unit and a control execution unit;

[0079] The data acquisition unit is used to acquire environmental data and initial state data of the mechanical arm;

[0080] The calculation processing unit uses the collected environmental data and initial state data of the mechanical arm as inputs, and uses the trained model to solve and calculate;

[0081] The control execution unit controls the mechanical arm to perform corresponding actions according to the obtained solution; and performs error correction in real time based on PID during the movement process.

[0082] Further, the data acquisition unit includes an ultrasonic mud level meter, a water flow sensor, a first inertial measurement unit, a second inertial measurement unit, a joint angle measurement sensor and a joint torque sensor;

[0083] The ultrasonic mud level meter is installed at the bottom of the bearing platform below the liquid surface, and emits ultrasonic signals to detect the height of the water bottom sludge layer; by detecting the height of the sludge layer, the action amount and the excavation depth of the mechanical arm are determined;

[0084] The water flow sensor is arranged at the bottom of the bearing platform to detect the water flow rate; by detecting the current water flow rate, the motion trend of the bearing platform can be calculated by using the model, and the compensation amount is set according to the motion trend, so as to reduce the error caused by the water fluctuation.

[0085] The first inertial measurement unit is installed on the bearing platform to detect the pose change of the bearing platform itself; by detecting the pose change of the bearing platform, the original data are obtained, so as to analyze the influence of the water flow rate and the center of gravity change in the movement process of the mechanical arm on the pose of the bearing platform.

[0086] The second inertial measurement unit is installed on the mechanical arm to detect the pose change of the end of the mechanical arm.

[0087] The joint angle measurement sensor is a Hall sensor, which is used to detect the angle of each joint of the mechanical arm.

[0088] The joint torque sensor is a sheet type torque sensor, which is used to detect the output torque of the joint; according to the torque output data of each joint, the power consumption can be optimized subsequently, so as to meet the dredging demand with the lowest action amount and reduce the energy consumption.

[0089] The laser or visual camera is synchronously installed on the mechanical arm, so as to identify the target object in the working area and facilitate the cleaning and transfer of the target object.

[0090] Embodiment 3

[0091] Figure 3 The structural schematic diagram of the computer system of the electronic device suitable for realizing the embodiments of the present application is shown.

[0092] It should be noted that the computer system of the electronic device in the present embodiment is only an example, and should not bring any limitation to the function and use range of the embodiments of the present application.

[0093] The computer system in the present embodiment includes a central processing unit 401, which can perform various appropriate actions and processes according to the programs stored in the read-only memory 402 or the programs loaded into the random access memory 403 from the storage part 408, such as the hydraulic mechanical arm solving method and system described in the above embodiments. In the random access memory 403, various programs and data required for system operation are also stored. The central processing unit 401, the read-only memory 402 and the random access memory 403 are connected to each other through the bus 404. The input / output interface 405 is also connected to the bus 404.

[0094] The following components are connected to the input / output interface 405: an input portion 406 including a keyboard, a mouse, etc.; an output portion 407 including a display such as a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), etc., and a speaker, etc.; a storage portion 408 including a hard disk, etc.; and a communication portion 409 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication portion 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to the input / output interface 405 as necessary. A removable media 411 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is attached to the drive 410 as necessary, so that a computer program read out therefrom is installed in the storage portion 408 as necessary.

[0095] In particular, the processes described above with reference to the flowcharts can be implemented as a computer software program according to embodiments of the present application. For example, embodiments of the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing a computer program for executing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via the communication portion 409, and / or installed from the removable media 411. When the computer program is executed by the central processing unit 401, various functions defined in the system of the present application are executed.

[0096] It should be noted that the computer-readable medium in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the two. The computer-readable storage medium may, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination of the above. More specific examples of the computer-readable storage medium can include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (Compact Disc Read-Only Memory, CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, device or apparatus. In the present application, the computer-readable signal medium can include a data signal carried in a baseband or as a part of a carrier wave, which carries computer-readable computer programs. Such a propagated data signal can take various forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, which can send, propagate or transmit programs for use by or in conjunction with an instruction execution system, device or apparatus. The computer programs contained on the computer-readable medium can be transmitted by any suitable medium, including but not limited to wireless, wired, or the like, or any suitable combination of the above.

[0097] The flowcharts and block diagrams in the drawings illustrate the possible implementation architectures, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In the flowcharts or block diagrams, each block can represent a module, a program segment or a part of code containing one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur in different order than that shown in the drawings. For example, two blocks that are shown in succession can actually be executed substantially in parallel, and sometimes in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams or flowcharts, and the combination of blocks in the block diagrams or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0098] The units described in the embodiments of the present application can be implemented by software, or by hardware, or by a combination of software and hardware. The units described can also be located in a processor. In some cases, the names of the units do not constitute a limitation on the units themselves.

[0099] According to an aspect of the present application, there is provided a computer program product or computer program, comprising computer instructions stored in a computer readable storage medium. A processor of a computer device reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions to cause the computer device to perform the method provided in the various optional implementation manners described above.

[0100] As another aspect, the present application also provides a computer readable medium, which can be included in the electronic device described in the above embodiments, or can exist separately without being assembled into the electronic device. The computer readable medium carries one or more programs, which, when executed by the electronic device, cause the electronic device to implement the hydraulic mechanical arm solving method and system described in the above embodiments.

[0101] It should be noted that, although several modules or units of the device for action execution are mentioned in the above detailed description, such division is not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided into several modules or units.

[0102] From the above description of the embodiments, those skilled in the art can easily understand that the example embodiments described herein can be implemented by software, or by software in combination with necessary hardware. Therefore, the technical solutions according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a U disk, a mobile hard disk, etc.) or a network, and includes several instructions to make a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) execute the methods according to the embodiments of the present application.

[0103] Here, those skilled in the art can understand that the specific operations of the various steps in the above technical solutions have been described in detail above with reference to the hydraulic mechanical arm solving method and system described in the above embodiments, and therefore, repeated descriptions will be omitted. Figures 1 to 2

[0104] ​In summary, the water mechanical arm solving method and system based on the embodiments of the application are illustrated, which establishes a motion model for the bearing platform by collecting data, introduces the motion trend output by the model into the D-H parameter model, and performs correction; uses the corrected model to solve by inverse kinematics to obtain control instructions; performs PID control in the process of controlling the operation of the mechanical arm to adjust the motion state of the mechanical arm. The deviation of the pose of the end of the mechanical arm and the three-dimensional position of the target object is collected, the current water flow speed and the position of the mechanical arm are taken as inputs, and a new solution is output to control the mechanical arm to move steadily towards the target object and complete the specified action.

Claims

1. A method for solving a watercraft robotic arm, the method comprising: Comprise the following specific steps: S1: obtain environment data and initial state of the robot arm through multi-sensor fusion; S2: establish a kinematics model coupled with dynamic water power; S3: solve using a hybrid inverse kinematics solving architecture; S4: suppress fluctuation interference through pre-compensation and real-time error correction; In step S1, the sensor is used to collect water flow velocity, bearing platform fluctuation data, robot arm joint angle and end position data; In step S2, the water power disturbance is converted into equivalent joint offset, and the standard D-H parameter model is modified. The output of the bearing platform motion model obtained in step S1 is superimposed into the D-H parameter model to construct a dynamic water power modified D-H model. Specifically as follows: In a fluctuating environment, the disturbance of the bearing platform is quantized as an equivalent D-H parameter correction: End effector displacement due to platform motion Δp = [Δx, Δy, Δz] T , decomposed to joints via Jacobian: Δq = J −1 (q)Δp; Corrected joint angle: θi ′ = θi + Δqi Correction transformation matrix: In the above equation, Δp is the end displacement caused by the action of the carrying platform; Δq is the equivalent angular displacement of each joint; J(q) is the Jacobian matrix of the robot arm; θi ′ is the corrected joint angle; Tt is the corrected transformation matrix; In step S3, the constraint conditions are set according to the environment data and the pose of the robot arm; the initial feasible solution is quickly generated by combining the analytical method; Specifically: (1) According to the physical parameters of the mechanical arm itself: link length, joint number, joint angle, set the constraint range, set the boundary condition with 80% of the maximum adjustment amount as the target; (2) According to the boundary range of the working scene, set the physical boundary condition: there are collision targets in the work area, and the boundary area is drawn within 1m of the collision target to avoid collision between the mechanical arm and the obstacle; (3) Energy consumption constraint: upper limit of joint torque square sum: Where i is the number of joints, determined by the hydraulic system pressure threshold; By setting the above three boundary conditions, the solution is obtained; First, solve targets 1 and 2, and use the minimum value of target 3 among the many solutions as the initial solution output; Use the feasible solution as the control command and input it to the control end of the mechanical arm; Control the mechanical arm to run, and modify it in real time according to the pose change of the mechanical arm during the running of the mechanical arm; In step S4, real-time error correction is performed on the running robot arm. When the robot arm needs to be controlled, the current water flow velocity and the initial state of the robot arm are detected and sent to the bearing platform motion model as inputs, and the pose change of the bearing platform caused by the robot arm action is outputted; The pose change is inputted into the kinematics model coupled with dynamic water power in step S2, and inverse kinematics is solved through the modified D-H parameter model. The target constraint is set according to the boundary condition in step S3, and the initial solution is obtained. The initial solution is inputted as the control quantity of the robot arm to control the operation of the robot arm. When the modified D-H parameter model is used for solving, the purpose of pre-compensation is achieved, the compensation quantity is inputted in advance, the error of the robot arm end is reduced to improve the precision. When the robot arm gets the control instruction, the motion state of the bearing platform and the robot arm is detected by the sensor, and the actual motion state of the bearing platform is compared with the estimated state outputted by the bearing platform motion model. When the amplitude of the actual motion state of the bearing platform and the estimated state has more than 10% action error, the PID control is started to adjust the motion state of the robot arm. The deviation between the pose of the robot arm end and the three-dimensional position of the target object is collected, and the current water flow velocity and the position of the robot arm are inputted to repeat steps S1-S3 to output a new solution, so that the robot arm can move steadily towards the target object and complete the specified action.

2. The watercraft robotic arm solving method of claim 1, wherein, Step S1 performs time calibration to match the environment data and the state data of the robot arm determined by the sensor parameters in time.

3. The watercraft robotic arm solving method of claim 1, wherein, In step S4, real-time error correction is performed on the running robot arm to improve the precision of the end pose of the robot arm.

4. A hydraulic manipulator solving system, solving a manipulator using the method of any one of claims 1 to 3, characterized by, Comprise a data acquisition unit, a calculation processing unit and a control execution unit; The data acquisition unit is used to collect environment data and initial state data of the robot arm; The calculation processing unit uses the collected environment data and initial state data of the robot arm as inputs, and uses the trained model to solve and calculate; The control execution unit controls the mechanical arm to perform corresponding actions according to the obtained solution; And in the process of movement, error correction is carried out in real time based on PID.

5. The hydraulic manipulator solving system according to claim 4, wherein, The data acquisition unit comprises an ultrasonic sludge level meter, a water flow sensor, a first inertial measurement unit, a second inertial measurement unit, a joint angle measurement sensor and a joint torque sensor; The ultrasonic sludge level meter is installed at the bottom of the bearing platform below the liquid surface and emits ultrasonic signals to detect the height of the sludge layer at the bottom of the water body; The water flow sensor is installed at the bottom of the bearing platform to detect the flow rate of the water body; The first inertial measurement unit is installed on the bearing platform to detect the pose change of the bearing platform itself; The second inertial measurement unit is installed on the mechanical arm to detect the pose change of the end of the mechanical arm; The joint angle measurement sensor is a Hall sensor for detecting the angle of each joint of the mechanical arm; The joint torque sensor is a sheet type torque sensor for detecting the output torque of the joint. 6.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is characterized in that: The processor executes the computer program to realize the steps of the water mechanical arm solving method in any one of claims 1-3.

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