Underwater mechanical arm dragging control method and mechanical arm system

Abstract

The invention relates to an underwater mechanical arm dragging control method and a mechanical arm system, and is suitable for the fields of ocean exploration, deep sea operation and the like. According to the method, dragging control input of an operator is received through a force feedback handle or virtual reality equipment, and input signals are converted into motion instructions of all joints of the mechanical arm through an inverse kinematics formula. The system is provided with a force sensor and an attitude sensor, feedback data of the underwater environment is collected in real time, the motion trail of the mechanical arm is dynamically optimized based on a PID control algorithm, and high precision and flexibility of the mechanical arm are kept in the complex underwater environment. The system has a multi-degree-of-freedom design and can execute diversified fine operation tasks, a force feedback mechanism ensures that an operator perceives force changes in real time, and the safety and accuracy of operation are improved. The wireless communication module ensures stable transmission of underwater signals, realizes remote operation and real-time feedback, and is suitable for complex underwater operation scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater robotic arms, and in particular to an underwater robotic arm dragging control method and a robotic arm system. Background Art

[0002] With the rapid development of marine resources and deep-sea scientific exploration, underwater robots, especially underwater manipulators, play an increasingly important role in marine engineering, oil and gas extraction, marine biological research, archaeological exploration, and maintenance of submarine cables and pipelines. As the key actuator of underwater operation robots, underwater manipulators can replace humans in performing delicate operations in harsh environments, such as grasping objects, installing equipment, cutting or welding, etc.

[0003] The control methods of traditional underwater robotic arms are mainly divided into two categories:

[0004] Manual control: The operator manually controls each joint of the robot arm through a remote control system. This method requires the operator to control the movement of the robot arm one by one. The operation process is complicated and requires the operator to have high professional skills. In addition, the complexity of the underwater environment makes the manual control response delayed and the error large, especially under external disturbances such as water flow, the operation accuracy of the robot arm is difficult to guarantee.

[0005] Pre-programmed control: In some relatively fixed operation scenarios, the robot arm performs fixed trajectory tasks through pre-programming. This method relies on precise planning before the task and cannot dynamically adapt to changes in the underwater environment. Especially when facing complex and changeable water flows or irregular operation objects, it lacks flexibility and the ability to respond to emergencies in real time.

[0006] In addition, the physical conditions of the underwater environment, such as water pressure, buoyancy, flow rate, etc., pose severe challenges to the precise control of the robotic arm. The real-time feedback of underwater operations is limited by the accuracy of sensors and the response speed of control systems. It is difficult for operators to obtain the same real-time information as above-water operations, which greatly reduces the efficiency and safety of operations.

[0007] In response to the above problems, some control technologies based on force feedback and human-computer interaction have emerged in recent years. For example, force feedback technology allows operators to sense the force of the robotic arm through touch and adjust the operation in time. However, traditional force feedback systems are mostly used in the air. In the complex underwater environment, the accuracy and response speed of the sensor still face huge challenges. In addition, the underwater communication environment is relatively harsh, and the signal transmission speed and stability are low, which further limits the flexibility and real-time performance of remote operation.

[0008] Current problems include:

[0009] Insufficient operation accuracy and flexibility: Traditional remote control methods have high requirements on operators, and due to the complexity of the underwater environment, the operation accuracy of the robotic arm is difficult to guarantee. At the same time, the pre-programmed method is difficult to adapt to the dynamic underwater environment.

[0010] Imperfect real-time feedback mechanism: The existing underwater robotic arms lack an effective real-time feedback mechanism. Operators cannot quickly perceive changes in the underwater environment during remote control, especially the lack of force feedback, which increases the difficulty of operation and affects the efficiency of task completion.

[0011] Poor adaptability to complex environments: The underwater environment is changeable, including ocean currents, waves, etc. Traditional control methods are difficult to adapt to these complex physical environments in real time, resulting in uncoordinated movements and low efficiency in the process of the robotic arm performing tasks.

[0012] To this end, we designed an underwater robotic arm dragging control method and a robotic arm system to solve the above problems. Summary of the invention

[0013] The purpose of the present invention is to provide an underwater robotic arm dragging control method and a robotic arm system to address the deficiencies of the prior art, so as to solve the problems raised in the background technology.

[0014] To achieve the above object, the present invention provides the following technical solution: a method for controlling the dragging of an underwater robotic arm, comprising the following steps:

[0015] Step 1: Obtain the drag control input signal. The operator inputs the drag control signal to the control system through the operation terminal, and the control system receives the signal in real time;

[0016] Step 2: Convert the drag control signal into the action command of the robot arm, and use the inverse kinematics equation to calculate the angles of each joint of the robot arm. The calculation formula is as follows:

[0017] θ i =f -1 (x, y, z)

[0018] Among them, θ i is the angle of the i-th joint of the robot, and x, y, z are the target positions of the end effector of the robot;

[0019] Step 3: Monitor underwater environmental feedback, collect force feedback and environmental data, including resistance, water flow speed and other information, through the sensor module installed on the robotic arm;

[0020] Step 4: Make dynamic adjustments based on the feedback data and use the control algorithm to process the motion trajectory of the robot arm. The adjustment formula is:

[0021] θ i(t+1)=θ i (t)+K f ·(F feedback -F set )

[0022] Among them, θ i (t+1) is the adjusted joint angle, K f is the feedback gain coefficient, F feedback is the force feedback signal, F set is the preset force value;

[0023] Step 5: The robot arm performs the action, and the operator can make real-time adjustments based on the feedback to complete the task.

[0024] As a preferred technical solution of the present invention, the control input signal is input through a force feedback handle, a virtual reality device or other control device, and the force feedback handle can provide real-time resistance feedback information to the operator.

[0025] As a preferred technical solution of the present invention, the inverse kinematics equation is calculated according to the multi-degree-of-freedom model of the manipulator, and the inverse kinematics solution formula is:

[0026] J(q)·Δq=ΔX

[0027] Among them, J(q) is the Jacobian matrix of the robot arm, Δq is the change in joint angle, and ΔX is the change in position of the end effector.

[0028] As a preferred technical solution of the present invention, the sensor module includes a force sensor, a posture sensor and a pressure sensor. The sensors can collect feedback data of the robotic arm in an underwater environment in real time, including information such as resistance, water flow pressure, and posture changes.

[0029] As a preferred technical solution of the present invention, the feedback optimization adjustment is performed based on an incremental PID control algorithm, and the PID control formula is:

[0030]

[0031] Among them, u(t) is the control output, e(t) is the error signal, K p ,K i ,K d are the proportional, integral and differential coefficients respectively.

[0032] As a preferred technical solution of the present invention, the robotic arm system adopts a multi-degree-of-freedom structure with at least 6 joints, which can achieve flexible movement in multiple directions to adapt to the complex underwater working environment.

[0033] The present invention also proposes an underwater robotic arm system, characterized in that it comprises:

[0034] A controller, used for receiving a drag control signal and generating a motion command for the robot arm;

[0035] The robot body includes joints with multiple degrees of freedom and end effectors, and waterproof sensors are installed at the joints;

[0036] The sensor module is installed at the end of the robotic arm to collect feedback data from the underwater environment;

[0037] An operating terminal through which the operator interacts with the control system, the terminal including a force feedback handle or a virtual reality device.

[0038] As a preferred technical solution of the present invention, the operating terminal transmits data with the controller via a wireless communication module. The wireless communication module has anti-interference capability and can ensure stable transmission of underwater signals.

[0039] As a preferred technical solution of the present invention, each joint of the robotic arm body is equipped with a force feedback sensor, which can sense the resistance or load applied to the joint in real time, and the sensor data is transmitted to the controller through the communication module.

[0040] As a preferred technical solution of the present invention, the controller has a high-performance computing chip for executing complex control algorithms and inverse kinematics solutions to ensure high-precision movement and dynamic response of the manipulator in complex underwater environments.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows: the underwater manipulator dragging control method and system of the present invention, by adopting the dragging control mode, makes the operation more intuitive and simple, and reduces the technical threshold of the operator. Through the force feedback handle and virtual reality equipment, the operator can control the manipulator in real time, and the system accurately converts the control signal into the motion command of the manipulator, combined with the multi-degree-of-freedom design, to ensure high-precision operation in complex environments, and improve the flexibility and accuracy of the operation.

[0042] The system has real-time feedback and dynamic adjustment functions. The sensor module can collect force feedback and posture data of the underwater environment. The control system uses the PID control algorithm to dynamically optimize the motion trajectory of the robot arm based on this feedback information, thereby adapting to changes in the external environment such as water flow and resistance to ensure the smooth completion of the task. In addition, the force feedback sensor can monitor the force of the robot arm in real time, enhancing the safety and stability of the operation.

[0043] The invention also supports remote operation and virtual reality interaction, and is equipped with an anti-interference wireless communication module to ensure stable transmission of underwater signals, significantly improving the real-time and smoothness of operations. Overall, the system has high precision, strong adaptability and safety, and is suitable for a variety of scenarios such as ocean exploration, deep-sea operations, and submarine facility maintenance, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of the underwater robotic arm dragging control method proposed by the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The following is combined with Figure 1 With reference to the accompanying drawings and a number of embodiments, specific embodiments of the present invention are described in detail.

[0047] Embodiment 1: Underwater manipulator dragging control method based on force feedback handle

[0048] This embodiment describes a method for controlling the dragging of an underwater manipulator arm based on a force feedback handle. The operator directly controls the movement of the underwater manipulator arm through the force feedback handle, and the force feedback handle provides real-time force feedback to help the operator perceive the external force exerted on the underwater manipulator arm.

[0049] Operation process: The operator inputs the drag command through the force feedback handle. The system calculates the motion trajectory of the underwater robotic arm in real time based on the displacement of the operator's handle and the force feedback signal.

[0050] The controller converts the operator's dragging action into the angle change of each joint of the robot arm through the inverse kinematics algorithm. The specific inverse kinematics formula is as follows:

[0051] θ i =f -1 (x, y, z)

[0052] Among them, θ i is the angle of the i-th joint, and x, y, and z are the target position coordinates of the end effector of the robot. The system dynamically adjusts the movement trajectory of the robot to ensure that it reaches the target position accurately by monitoring the posture of the robot and the changes in the underwater environment in real time through sensors.

[0053] Force feedback mechanism: The force feedback handle will generate corresponding feedback force according to the resistance encountered by the robotic arm and other force fields in the environment, providing the operator with real tactile feedback.

[0054] The calculation formula for force feedback is:

[0055] F feedback =K f ·(F environment -F set )

[0056] Among them, F feedback The feedback force provided by the handle, F environment is the environmental force detected by the sensor at the end of the robot arm, F set is the target force set for the system, K f is the feedback gain.

[0057] Dynamic adjustment: = The system dynamically adjusts the joint angle of the robot arm through the PID controller to ensure the stability and accuracy of the robot arm's movement. The PID control formula is as follows:

[0058]

[0059] Where e(t) is the error between the current position of the robot and the target position, K p , K i , K d are the proportional, integral, and differential coefficients respectively.

[0060] Ultimately, the robotic arm performs the task according to the optimized trajectory, and the operator adjusts the operation based on the force feedback of the handle to ensure the accuracy and safety of the operation.

[0061] In this embodiment, through the force feedback handle, the operator can sense the force changes in the underwater environment in real time and adjust the operation accordingly, which has high flexibility and precision.

[0062] Embodiment 2: Virtual reality assisted underwater robotic arm control method

[0063] In this embodiment, the operator uses a virtual reality device (as described in claim 2) to control the underwater manipulator: the operator wears a virtual reality (VR) helmet and operates through the underwater environment in the virtual scene. The virtual reality system can present a real underwater operation scene, including the state of the manipulator and real-time data of the underwater environment. The operator sends a drag control signal through the control device of the virtual reality system, and the control system receives the signal in real time, and converts the operation in the virtual reality into the motion parameters of each joint of the manipulator through inverse kinematics calculation.

[0064] The control system also obtains feedback information about the underwater environment from the sensor module, including data such as water flow resistance and posture changes of the robotic arm.

[0065] These data are fed back to the virtual reality system through sensors, and the operator can perceive the changes in the underwater environment in real time in the virtual environment.

[0066] The control system uses the optimization algorithm to dynamically adjust the motion trajectory of the robotic arm based on the feedback information to ensure that the robotic arm can adapt to the complex underwater environment. The specific optimization process is shown in the formula:

[0067] θ i (t+1)=θ i (t)+K f ·(F feedback -F set )

[0068] Among them, θ i (t+1) is the adjusted joint angle, K f is the feedback gain coefficient, F feedback The force feedback signal provided by the sensor, F set is the preset force value.

[0069] The operator can intuitively adjust the operation of the robotic arm through the virtual reality device to ensure the successful completion of the task. This embodiment enhances the operator's perception ability through virtual reality technology, especially in an invisible underwater environment, the operator can accurately control the robotic arm, significantly improving the intuitiveness and efficiency of the operation.

[0070] Example 3: Application of multi-degree-of-freedom underwater robotic arm

[0071] In this embodiment, the underwater robotic arm has up to 6 degrees of freedom and has high flexibility: the robotic arm includes 6 joints, each joint has an independent control unit, and can rotate and move freely in different directions to adapt to diverse operational requirements in underwater environments.

[0072] The end effector of the robotic arm is equipped with high-precision force sensors and attitude sensors, which can accurately sense the water flow resistance and attitude changes in the environment.

[0073] The controller of the robot arm adjusts the angle of each joint in real time according to the sensor feedback. It calculates the difference between the expected position and the actual position of the end effector of the robot arm and uses the Jacobian matrix to solve the adjustment amount of each joint:

[0074] J(q)·Δq=ΔX

[0075] Among them, J(q) is the Jacobian matrix, Δq is the change in joint angle, and ΔX is the displacement of the end effector.

[0076] Based on the characteristics of the multi-degree-of-freedom robotic arm, the system is able to perform various tasks such as grasping, cutting, and welding in complex underwater terrain.

[0077] The multi-degree-of-freedom robotic arm system in this embodiment can flexibly cope with complex underwater operating environments and is suitable for operating requirements in a variety of scenarios.

[0078] Example 4: Application of wireless communication module in underwater robotic arm

[0079] In this embodiment, the underwater manipulator system is equipped with an anti-interference wireless communication module:

[0080] The controller and the operating terminal transmit data via the wireless communication module to ensure that the control signals and sensor feedback of the robot arm can be transmitted in a timely manner.

[0081] The wireless communication module has anti-interference function and can transmit stably in complex underwater signal environments, avoiding communication interruptions caused by underwater obstacles or other signal interference.

[0082] The operator sends the drag control signal through the operation terminal, and the wireless communication module quickly transmits it to the controller to ensure the real-time operation;

[0083] At the same time, the feedback data from the underwater sensor is also transmitted back to the operation terminal through the communication module to achieve closed-loop control.

[0084] This embodiment ensures the stable communication and real-time control capabilities of the underwater robotic arm system in a deep-sea environment through the application of the wireless communication module.

[0085] Example 5: Application of force feedback sensor in underwater manipulator system

[0086] In this embodiment, each joint of the underwater manipulator is equipped with a force feedback sensor:

[0087] The force feedback sensors at each joint monitor in real time the external forces acting on the robotic arm during movement, including water flow resistance, load weight and other information.

[0088] The sensor transmits this force feedback information to the controller, which dynamically adjusts the motion trajectory of the robotic arm based on the feedback information to ensure that the robotic arm can balance external forces and maintain stability when performing tasks.

[0089] When operating the robotic arm, the operator can use the handle or virtual reality device to sense the external force on the robotic arm in real time and adjust the operation in time to avoid damage to the robotic arm or mission failure.

[0090] The force feedback sensor in this embodiment can effectively improve the safety and operating accuracy of the robotic arm and is suitable for high-precision underwater operation scenarios.

[0091] Through the detailed description of the above multiple embodiments, the underwater manipulator dragging control method and system of the present invention can effectively cope with complex underwater operating environments, and has the advantages of high precision, high flexibility, intuitive operation, etc. These embodiments can achieve efficient and stable control effects in different scenarios, and are suitable for multiple fields such as marine exploration, oil extraction, and underwater rescue.

[0092] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the dragging of an underwater robotic arm, characterized in that: The following steps are involved: Step 1: Obtain the drag control input signal. The operator inputs the drag control signal to the control system through the operation terminal, and the control system receives the signal in real time; Step 2: Convert the drag control signal into the action command of the robot arm, and use the inverse kinematics equation to calculate the angles of each joint of the robot arm. The calculation formula is as follows: θ i =f -1 (x,y,z) Among them, θ i is the angle of the i-th joint of the robot, and x, y, z are the target positions of the end effector of the robot; Step 3: Monitor underwater environmental feedback, collect force feedback and environmental data, including resistance and water flow speed information, through the sensor module installed on the robotic arm; Step 4: Make dynamic adjustments based on the feedback data and use the control algorithm to process the motion trajectory of the robot arm. The adjustment formula is: i i (t+1)=θ i (t)+K f ·(F feedback -F set ) Among them, θ i (t+1) is the adjusted joint angle, K f is the feedback gain coefficient, F feedback is the force feedback signal, F set is the preset force value; Step 5: The robot arm performs the action, and the operator can make real-time adjustments based on the feedback to complete the task.

2. The dragging control method of the underwater robot arm according to claim 1, characterized in that: The control input signal is input through a force feedback handle and a virtual reality device, and the force feedback handle provides real-time resistance feedback information to the operator.

3. The dragging control method of the underwater robot arm according to claim 1, characterized in that: The inverse kinematics equation is calculated based on the multi-degree-of-freedom model of the robotic arm, and the inverse kinematics solution formula is: J(q)·Δq=ΔX Among them, J(q) is the Jacobian matrix of the robot arm, Δq is the change in joint angle, and ΔX is the change in position of the end effector.

4. The dragging control method of the underwater robot arm according to claim 1, characterized in that: The sensor module includes a force sensor, a posture sensor and a pressure sensor. The sensors can collect feedback data of the robotic arm in an underwater environment in real time, including resistance, water flow pressure, and posture change information.

5. The dragging control method of the underwater robot arm according to claim 1, characterized in that: The feedback optimization adjustment is based on an incremental PID control algorithm, and the PID control formula is: Among them, u(t) is the control output, e(t) is the error signal, K p ,K i ,K d are the proportional, integral and differential coefficients respectively.

6. The dragging control method of the underwater robot arm according to claim 1, characterized in that: The robotic arm system adopts a multi-degree-of-freedom structure and has at least 6 joints.

7. An underwater robotic arm system, characterized in that: include: Controller: used to receive the drag control signal and generate the motion command of the robot arm; The robot body: includes joints with multiple degrees of freedom and end effectors, and waterproof sensors are installed at the joints; Sensor module: installed at the end of the robotic arm to collect feedback data from the underwater environment; Operation terminal: The operator interacts with the control system through this terminal, which includes a force feedback handle or a virtual reality device.

8. The underwater robotic arm system according to claim 7, characterized in that: The operation terminal transmits data with the controller via the wireless communication module.

9. The underwater robotic arm system according to claim 7, characterized in that: Each joint of the robot body is equipped with a force feedback sensor, and the sensor data is transmitted to the controller through the communication module.

10. The underwater robotic arm system according to claim 7, characterized in that: The controller is used to execute complex control algorithms and inverse kinematics solutions.

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