Method for establishing dynamic model of underwater operation robot

Abstract

The invention discloses a method for establishing a kinetic model of an underwater operation robot, and relates to the field of underwater robotics.The method comprises the steps that firstly, a motion model of the underwater operation robot is established and simulated, a robot model is designed through a three-dimensional tool, and a terrain model of an underwater environment is established in combination with a geographic information system (GIS); meanwhile, an inertial coordinate system and a coordinate system of the robot are further defined according to the established model, the position and the posture of the robot in the space are analyzed, and the position and the posture of the robot in the space are obtained by analyzing and calculating the translational motion coefficient Py and the rotational motion coefficient Xz of the robot and then presetting a posture threshold value Z; and performing comparison evaluation on the attitude change coefficient Jq of the robot, and if the attitude of the robot is found to be abnormal, namely the attitude change coefficient Jq of the robot exceeds a preset attitude threshold value Z, further analyzing the influence of the underwater environment on the attitude of the robot, and performing real-time regulation and control on the power output of the robot according to the underwater environment.

Description

Technical Field

[0001] The invention relates to the technical field of underwater robots, and in particular to a method for establishing a dynamics model of an underwater operating robot. Background Art

[0002] Underwater robots are robots designed specifically for underwater environments and are capable of performing a variety of tasks. These robots can be divided into two categories: remote-controlled underwater robots and autonomous underwater robots. With the increase in the development of marine resources, especially the extraction of oil and gas, underwater robot technology has developed rapidly. Early underwater robots were mainly remote-controlled, while in recent years, autonomous underwater robots have gradually emerged and are able to perform complex tasks without human operation.

[0003] In the Chinese invention application with application publication number CN112306076A, a method for establishing a dynamic model of a hybrid-driven underwater robot is disclosed. First, the motion parameters and degrees of freedom of the underwater robot are determined; all supporting legs are folded into a virtual supporting leg with mass, and the sagittal plane dynamic model of the hybrid-driven underwater robot under the action of hydrodynamic force and driving force is established by using the Lagrangian principle; on this basis, in view of the problem that the massive swinging leg is difficult to model, its influence on the dynamic model of the underwater robot is parameterized, and the sagittal plane dynamic model of the hybrid-driven underwater robot with massive swinging legs is established. The dynamic model according to the present invention can reveal the motion mechanism of the hybrid-driven underwater robot climbing on the wall, so as to analyze the influence of the virtual supporting leg and the swinging leg on the hybrid-driven underwater robot body, provide the control force required for the movement of the hybrid-driven underwater robot, and lay a good foundation for the design of the controller.

[0004] In combination with the prior art, the above application still has the following deficiencies: At present, when underwater operations are carried out underwater, the position and posture of the robot in the water are relatively unstable. The resultant force of the water environment in different waters changes in real time. The robot stabilizes its posture and position underwater without considering the loss. This method is often not easy for the underwater robot to operate in the water for a long time, and to cope with the real-time changing underwater environment, resulting in unstable posture and motion trajectory deviation of the robot when operating underwater. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for establishing a dynamic model of an underwater working robot, which solves the problems mentioned in the background technology.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for establishing a dynamic model of an underwater working robot comprises the following steps: S1. First, a robot model of the same scale is established according to the type of underwater operation robot, and a simulation model of the underwater environment is created, and the robot model is placed in the underwater environment simulation model for motion simulation; S2. Define the inertial coordinate system and the robot's own coordinate system, analyze the posture change of the underwater working robot model in the three-dimensional space, construct the translation motion equation and the rotation motion equation to analyze the position and posture change of the robot model, analyze and calculate to obtain the machine translation motion coefficient Py and the machine rotation motion coefficient Xz, and associate the machine translation motion coefficient Py and the machine rotation motion coefficient Xz to obtain the machine posture change coefficient Jq; S3, then compare and evaluate the preset attitude threshold Z with the obtained machine attitude change coefficient Jq, and the attitude change of the underwater working robot model in the three-dimensional space; S4. When the posture is abnormal, the underwater environment is further analyzed, and the comprehensive motion coefficient Hl is obtained by performing correlation calculations based on the combined force received by the robot in the underwater environment; S5. Finally, a power threshold D is preset according to the obtained comprehensive motion coefficient H1, and a comparative evaluation is performed. The power of the underwater working robot is adjusted according to the evaluation result to stabilize the posture of the robot during underwater motion.

[0007] Preferably, by using SolidWorks 3D modeling, a robot model of the same scale is designed and established according to the selected robot type, and the appearance, joint structure and motion characteristics of the robot model are accurately modeled. At the same time, a geographic information system GIS is used to establish a terrain model of the underwater environment. The robot model and the underwater environment model are imported into the physical simulation engine Unity, and the physical engine is used to simulate physical interactions in the underwater environment, including but not limited to water flow resistance, buoyancy and gravity.

[0008] Preferably, the earth coordinate system is set as the global fixed basic coordinate system and defined as the inertial coordinate system. The inertial coordinate system is defined as a right-handed coordinate system. The X1 axis is defined as pointing to the east, the Y1 axis is defined as pointing to the north, and the Z1 axis is defined as pointing upward. The absolute position and posture of the robot in space are analyzed. At the same time, the robot's own coordinate system is fixed to the robot's body, and the robot's position and posture relative to itself are analyzed and defined as the robot's own coordinate system. The robot's own coordinate system is defined as a right-handed coordinate system. The X2 axis is positioned to point in the direction of the robot's forward movement, the Y2 axis is defined to point to the left side of the robot, and the Z2 axis is defined to point to the top of the robot.

[0009] Preferably, the position change of the robot in three-dimensional space is analyzed by using the translation motion equation through the defined inertial coordinate system and the robot's own coordinate system, and the translation of the current underwater simulation robot is calculated by using the three-dimensional vector It means that at this time, the machine translation motion coefficient Py is calculated through the translation motion equation; The translation motion coefficient Py is obtained by the following formula: ; Where v represents the velocity vector of the robot, v x1 、v y1 and v z1 They represent the robot in three-dimensional space, x 1 Axis, y 1 Axis and z 1 The velocity component of the axis, T represents the transpose operation of the vector, Py, Xz, v, w and q, which are vectors representing position, attitude, velocity, angular velocity and quaternion, are all column vectors, and the transpose operation T represents the operation of converting these column vectors into row vectors.

[0010] Preferably, the rotational motion equation is used to analyze the posture change of the robot in three-dimensional space, and the posture of the current underwater simulation robot is expressed by quaternion. Indicates that, by combining the robot's angular velocity , to obtain the machine rotational motion coefficient Xz; The machine rotational motion coefficient Xz is obtained by the following formula: ; In the formula, represents the four-element selection matrix, q b represents the real part of the quaternion, q x2 ,q y2 and q z2 Represents the imaginary part of the quaternion, w x2 、w y2 and w z2 They represent the robot's rotation around x 2 Axis, y 2 Axis and z 2 Axis, quaternion q is used to describe the posture of the robot, including direction and rotation angle.

[0011] Preferably, the obtained translation motion coefficient Py and machine rotation motion coefficient Xz are dimensionlessly processed and then correlated to calculate and output the machine posture change coefficient Jq; The machine posture change coefficient Jq is obtained by the following formula: ; Wherein, a1 and a2 represent the preset weight values ​​of the translation motion coefficient Py and the machine rotation motion coefficient Xz respectively, and a1≠a2, 0<a1<0.66, 0<a2<0.34, and the specific values ​​are adjusted and set by the user, and A is the correction constant.

[0012] Preferably, a preset attitude threshold Z is set for the underwater working robot according to the actual water environment and the power output of the machine, and then a comparative evaluation is performed with the obtained machine attitude change coefficient Jq to analyze the current underwater working robot model in three-dimensional space. The specific evaluation method is as follows; When the machine attitude change coefficient Jq> attitude threshold Z, it means that the current robot's underwater power output causes the robot's attitude to deviate in the positive direction of motion. At this time, the underwater environment is further analyzed to adjust the power output of the robot's attitude. When the robot attitude change coefficient Jq = attitude threshold Z, it means that the current robot's power output underwater is normal and the robot's attitude is stable, and no further analysis is required at this time; When the machine posture change coefficient Jq is less than the posture threshold Z, it means that the current robot has abnormal hydrodynamic output, which causes the machine posture to deviate in the reverse motion direction. At this time, the underwater environment is further analyzed to adjust the power output of the robot posture.

[0013] Preferably, when the underwater robot model is in a simulated water environment and the power output causes an abnormal posture, the water force acting on the underwater working robot is comprehensively analyzed to perform a comprehensive analysis of the power output, wherein the water force includes buoyancy Sfl, the robot's gravity in water Szl and water flow resistance Slz.

[0014] Preferably, a comprehensive formula is constructed to analyze the effect of the underwater environment on the kinematics and dynamics of the robot, and the resultant force of the water body is dimensionlessly processed and then correlated with the translational motion coefficient Py of the robot and the velocity vector v of the robot to obtain the comprehensive motion coefficient Hl; The comprehensive motion coefficient H1 is obtained by the following formula: .

[0015] Preferably, the preset power threshold D and the obtained comprehensive motion coefficient H1 are used for comparative analysis, the power output of the current underwater robot is analyzed, and the power output is regulated. The specific evaluation scheme is as follows; When the comprehensive motion coefficient Hl> the power threshold D, it means that the buoyancy of the current water environment is abnormal, which affects the posture and power of the robot. At this time, the propulsion force needs to be reduced step by step, and the propulsion force needs to be reduced by 5% each level to adjust the posture of the underwater robot; When the comprehensive motion coefficient Hl ≤ the power threshold D, it means that the water flow resistance of the current water environment is abnormal, which affects the posture and power of the robot. At this time, the propulsion force needs to be increased step by step, with each level increasing by 10%, to adjust the posture of the underwater robot.

[0016] Beneficial Effects The present invention provides a method for establishing a dynamic model of an underwater working robot. It has the following beneficial effects: (1) First, this method establishes and simulates the motion model of the underwater working robot, designs the robot model using tools such as SolidWorks, and establishes the terrain model of the underwater environment in combination with the geographic information system. This provides an accurate basis for subsequent simulation analysis. After establishing the robot model and the underwater environment simulation model, this method further defines the inertial coordinate system and the robot's own coordinate system, and analyzes the position and posture of the robot in space. By analyzing and calculating the robot's translational motion coefficient Py and rotational motion coefficient Xz, the robot's position and posture changes in three-dimensional space can be accurately understood. Then, the preset posture threshold Z is compared and evaluated with the machine posture change coefficient Jq. If the robot's posture is abnormal, that is, the machine posture change coefficient Jq exceeds the preset posture threshold Z, the method will further analyze the impact of the underwater environment on the robot's posture. When an abnormal posture is found, the method will comprehensively analyze the resultant force of the water body acting on the robot, analyze the impact of the underwater environment on the robot's kinematics and dynamics by constructing a comprehensive formula, and perform dimensionless processing to obtain the comprehensive motion coefficient Hl. Finally, the method sets a preset power threshold D based on the obtained comprehensive motion coefficient Hl, performs comparative analysis, and adjusts the robot's power output in real time according to the underwater environment.

[0017] (2) This method conducts a comprehensive analysis of factors such as buoyancy, water flow resistance, and gravity that the robot is subject to in the underwater environment, and constructs a comprehensive formula for dimensionless processing. This enables the robot to analyze the complex and ever-changing underwater environment in real time, effectively respond to various physical interactions in the environment, and improve the robot's working performance and reliability under different underwater operating conditions.

[0018] By setting the attitude threshold Z and power threshold D, and comparing and evaluating with the acquired attitude change coefficient Jq and comprehensive motion coefficient Hl, the power output of the robot can be accurately adjusted. This dynamic power control method not only ensures the stable operation of the robot, but also can flexibly adjust the propulsion force according to the actual situation, thereby improving the working efficiency, reducing energy consumption, and extending the working time of the robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a schematic diagram of the steps of a method for establishing a dynamic model of an underwater working robot. DETAILED DESCRIPTION

[0020] 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.

[0021] Example 1 The present invention provides a method for establishing a dynamic model of an underwater operation robot. Figure 1 , including the following steps: S1. First, a robot model of the same scale is established according to the type of underwater operation robot, and a simulation model of the underwater environment is created, and the robot model is placed in the underwater environment simulation model for motion simulation; S2. Define the inertial coordinate system and the robot's own coordinate system, analyze the posture change of the underwater working robot model in the three-dimensional space, construct the translation motion equation and the rotation motion equation to analyze the position and posture change of the robot model, analyze and calculate to obtain the machine translation motion coefficient Py and the machine rotation motion coefficient Xz, and associate the machine translation motion coefficient Py and the machine rotation motion coefficient Xz to obtain the machine posture change coefficient Jq; S3, then compare and evaluate the preset attitude threshold Z with the obtained machine attitude change coefficient Jq, and the attitude change of the underwater working robot model in the three-dimensional space; S4. When the posture is abnormal, the underwater environment is further analyzed, and the comprehensive motion coefficient Hl is obtained by performing correlation calculations based on the combined force received by the robot in the underwater environment; S5. Finally, a power threshold D is preset according to the obtained comprehensive motion coefficient H1, and a comparative evaluation is performed. The power of the underwater working robot is adjusted according to the evaluation result to stabilize the posture of the robot during underwater motion.

[0022] In this embodiment, the method creates a robot model of the same scale according to the type of underwater working robot, and establishes a simulation model of the underwater environment. The robot model is embedded in the simulation environment, motion simulation is performed, the inertial coordinate system and the robot's own coordinate system are determined, and the posture change of the underwater working robot in three-dimensional space is analyzed. The translation and rotation motion equations are constructed, the translation motion coefficient Py and the rotation motion coefficient Xz of the robot are calculated, and the machine posture change coefficient Jq is obtained by association. A preset posture threshold Z is set, and it is compared and evaluated with the machine posture change coefficient Jq to analyze the posture change of the underwater working robot model in three-dimensional space. If the posture is abnormal, the underwater environment is further analyzed, and the comprehensive motion coefficient Hl is calculated and obtained in combination with the combined force received by the robot. According to the obtained comprehensive motion coefficient Hl, a preset power threshold D is set, and a comparative evaluation is performed. According to the evaluation result, the power of the underwater working robot is adjusted to stabilize the robot's motion posture underwater. Through this optimization process, effective management of the posture stability and motion control of the underwater working robot will be achieved, thereby improving the efficiency and safety of underwater operations.

[0023] Example 2 This embodiment is explained in Example 1, please refer to Figure 1 Specifically: By using SolidWorks 3D modeling, according to the selected robot type, a robot model of the same scale is designed and established, and the appearance, joint structure and motion characteristics of the robot model are accurately modeled. At the same time, the geographic information system GIS is used to establish a terrain model of the underwater environment. The robot model and the underwater environment model are imported into the physical simulation engine Unity, and the physical engine is used to simulate the physical interactions in the underwater environment, including but not limited to water flow resistance, buoyancy and gravity.

[0024] In this embodiment, the use of SolidWorks for three-dimensional modeling can ensure accurate modeling of the selected robot type, including appearance, joint structure and motion characteristics, thereby improving the authenticity and accuracy of the robot model. Through the accurate modeling of the robot model, the robot's motion characteristics and posture changes can be better understood. Using the geographic information system GIS to establish a terrain model of the underwater environment can provide a real underwater environment scene, which helps to simulate various underwater terrain conditions. Such a terrain model can provide a more realistic scene for underwater operations, making the simulation results more reliable. The robot model and the underwater environment model are imported into it using the physical simulation engine Unity, and the physical engine is used to simulate the physical interaction in the underwater environment, including water flow resistance, buoyancy and gravity, etc., which helps to better simulate the impact of the underwater environment on the robot's motion. Such simulation can help predict the movement of the robot in different underwater environments, provide important references for design and control, and improve the performance and stability of the underwater operation robot. In summary, using SolidWorks for modeling, GIS to establish a terrain model and Unity for physical simulation can improve the authenticity and accuracy of the underwater operation robot simulation, provide strong support for optimizing design and control, and thus improve the efficiency and safety of underwater operations.

[0025] Example 3 This embodiment is explained in Example 1, please refer to Figure 1 Specifically: the earth coordinate system is set as the global fixed basic coordinate system and defined as the inertial coordinate system. The inertial coordinate system is defined as a right-handed coordinate system. The X1 axis is defined as pointing to the east, the Y1 axis is pointing to the north, and the Z1 axis is pointing upward. The absolute position and posture of the robot in space are analyzed. At the same time, the robot's own coordinate system is fixed to the robot's body, and the robot's position and posture relative to itself are analyzed and defined as the robot's own coordinate system. The robot's own coordinate system is defined as a right-handed coordinate system. The X2 axis is positioned to point to the robot's forward direction, the Y2 axis is defined to point to the robot's left side, and the Z2 axis is defined to point to the top of the robot.

[0026] Through the defined inertial coordinate system and the robot's own coordinate system, the translation motion equation is used to analyze the position change of the robot in three-dimensional space, and the translation of the current underwater simulation robot is calculated using a three-dimensional vector It means that at this time, the machine translation motion coefficient Py is calculated through the translation motion equation; The translation motion coefficient Py is obtained by the following formula; ; Where v represents the velocity vector of the robot, v x1 、v y1 and v z1They represent the robot in three-dimensional space, x 1 Axis, y 1 Axis and z 1 The velocity component of the axis, T represents the transpose operation of the vector, Py, Xz, v, w and q, which are vectors representing position, attitude, velocity, angular velocity and quaternion, are all column vectors, and the transpose operation T represents the operation of converting these column vectors into row vectors.

[0027] The rotational motion equation is used to analyze the robot's posture changes in three-dimensional space, and the quaternion is used to calculate the current underwater simulation robot's posture. Indicates that, by combining the robot's angular velocity , to obtain the machine rotational motion coefficient Xz; The machine rotational motion coefficient Xz is obtained by the following formula; ; In the formula, represents the four-element selection matrix, q b represents the real part of the quaternion, q x2 ,q y2 and q z2 Represents the imaginary part of the quaternion, w x2 、w y2 and w z2 They represent the robot's rotation around x 2 Axis, y 2 Axis and z 2 Axis, quaternion q is used to describe the posture of the robot, including direction and rotation angle.

[0028] In this embodiment, the earth coordinate system is defined as the global fixed basic coordinate system, and the inertial coordinate system of the right-handed coordinate system is used to describe the absolute position and posture of the robot in space, which helps to establish a unified coordinate system, making the analysis of the robot's motion clearer and more accurate. By fixing the robot's own coordinate system to the robot's body and defining it as a right-handed coordinate system, the robot's position and posture relative to itself can be better described, which helps to understand and control the robot's motion. Using the translational motion equation and the rotational motion equation to analyze the robot's position and posture changes, and calculating the robot's translational motion coefficient Py and rotational motion coefficient Xz, it helps to accurately understand the robot's position and posture changes in three-dimensional space. Such analysis can provide an important basis for subsequent attitude stability control, thereby improving the robot's motion stability and accuracy in underwater operations.

[0029] Example 4 This embodiment is explained in Example 1, please refer to Figure 1Specifically: the obtained translation motion coefficient Py and machine rotation motion coefficient Xz are dimensionlessly processed, and then the machine posture change coefficient Jq is calculated and outputted in association; The machine posture change coefficient Jq is obtained by the following formula; ; Wherein, a1 and a2 represent the preset weight values ​​of the translation motion coefficient Py and the machine rotation motion coefficient Xz respectively, and a1≠a2, 0<a1<0.66, 0<a2<0.34, and the specific values ​​are adjusted and set by the user, and A is the correction constant.

[0030] By presetting the attitude threshold Z of the underwater working robot according to the actual water environment and the power output of the machine, and then comparing and evaluating it with the obtained machine attitude change coefficient Jq, the current underwater working robot model in the three-dimensional space is analyzed. The specific evaluation method is as follows; When the machine attitude change coefficient Jq> attitude threshold Z, it means that the current robot's underwater power output causes the robot's attitude to deviate in the positive direction of motion. At this time, the underwater environment is further analyzed to adjust the power output of the robot's attitude. When the robot attitude change coefficient Jq = attitude threshold Z, it means that the current robot's power output underwater is normal and the robot's attitude is stable, and no further analysis is required at this time; When the machine posture change coefficient Jq is less than the posture threshold Z, it means that the current robot has abnormal hydrodynamic output, which causes the machine posture to deviate in the reverse motion direction. At this time, the underwater environment is further analyzed to adjust the power output of the robot posture.

[0031] In this embodiment, by dimensionlessly processing the translation motion coefficient Py and the machine rotation motion coefficient Xz, and calculating the machine attitude change coefficient Jq according to the weight value set by the user, the position and attitude change of the robot can be unified, which is helpful for quantifying and analyzing the robot attitude change. By setting a preset attitude threshold Z and comparing and evaluating it with the calculated machine attitude change coefficient Jq, the attitude change of the robot in underwater operation can be monitored and evaluated in real time. When the machine attitude change coefficient Jq exceeds the preset attitude threshold Z, the abnormal situation of the robot attitude can be discovered in time, and further analysis can be performed. According to the results of the comparative evaluation, the power output of the underwater operation robot can be adjusted in time to stabilize the robot's motion posture underwater. When the machine attitude change coefficient Jq is greater than the attitude threshold Z, the power output of the robot can be adjusted to make the robot attitude tend to be stable; when the machine attitude change coefficient Jq is less than the attitude threshold Z, it is necessary to analyze and adjust the power output of the underwater environment to the robot attitude to ensure the stability of the robot attitude. Such an adjustment control strategy helps to improve the attitude control ability of the underwater operation robot in a complex underwater environment, thereby improving the operation efficiency and safety.

[0032] Example 5 This embodiment is explained in Example 1, please refer to Figure 1 Specifically: when the underwater robot model is in a simulated water environment and the power output causes an abnormal posture, the water force acting on the underwater working robot is comprehensively analyzed to perform a comprehensive analysis of the power output, where the water force includes the buoyancy Sfl, the robot's gravity in water Szl, and the water flow resistance Slz.

[0033] By constructing a comprehensive formula to analyze the effect of the underwater environment on the robot's kinematics and dynamics, the water force is dimensionlessly processed and then correlated with the robot's translational motion coefficient Py and the robot's velocity vector v to obtain the comprehensive motion coefficient Hl. The comprehensive motion coefficient Hl is obtained by the following formula; .

[0034] It is used to compare and analyze the preset power threshold D with the obtained comprehensive motion coefficient Hl, analyze the power output of the current underwater robot, and adjust it. The specific evaluation plan is as follows; When the comprehensive motion coefficient Hl> the power threshold D, it means that the buoyancy of the current water environment is abnormal, which affects the posture and power of the robot. At this time, the propulsion force needs to be reduced step by step, and the propulsion force needs to be reduced by 5% each level to adjust the posture of the underwater robot; When the comprehensive motion coefficient Hl ≤ the power threshold D, it means that the water flow resistance of the current water environment is abnormal, which affects the posture and power of the robot. At this time, the propulsion force needs to be increased step by step, with each level increasing by 10%, to adjust the posture of the underwater robot.

[0035] In this embodiment, by comprehensively analyzing the combined force of the water body on the underwater working robot, including buoyancy, gravity in water and water flow resistance, the influence of the underwater environment on the robot can be more comprehensively understood, so as to adjust the power output of the robot in a targeted manner. The combined force of the water body is dimensionless, and the comprehensive motion coefficient H1 is calculated by associating it with the translational motion coefficient Py and the velocity vector v of the robot, so as to quantify the kinematic and dynamic influence of the underwater environment on the robot, and to a certain extent eliminate the influence of unit inconsistency, so that the comprehensive motion coefficient is more comparable and practical. By setting a preset power threshold D and comparing and analyzing it with the comprehensive motion coefficient H1, the abnormal situation of the water body environment can be discovered in time, and the power output of the current underwater robot can be specifically analyzed. When the comprehensive motion coefficient H1 exceeds the power threshold D, it indicates that the buoyancy is abnormal. At this time, the posture of the robot is adjusted by gradually reducing the propulsion force, which helps to reduce the posture deviation and maintain stability; when the comprehensive motion coefficient H1 is less than or equal to the power threshold D, it indicates that the water flow resistance is abnormal. By gradually increasing the propulsion force to adjust the posture of the robot, it helps to improve the stability and power output of the robot, thereby ensuring the normal operation of the underwater robot. Such an adjustment strategy helps to improve the adaptability and motion control effect of underwater robots in complex underwater environments, and through step-by-step regulation, it can reduce energy consumption by maintaining a stable state through minimum power output.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for establishing a dynamic model of an underwater working robot, characterized in that: The following steps are involved: S1. First, a robot model of the same scale is established according to the type of underwater operation robot, and a simulation model of the underwater environment is created, and the robot model is placed in the underwater environment simulation model for motion simulation; S2. Define the inertial coordinate system and the robot's own coordinate system, analyze the posture change of the underwater working robot model in the three-dimensional space, construct the translation motion equation and the rotation motion equation to analyze the position and posture change of the robot model, analyze and calculate to obtain the machine translation motion coefficient Py and the machine rotation motion coefficient Xz, and associate the machine translation motion coefficient Py and the machine rotation motion coefficient Xz to obtain the machine posture change coefficient Jq; S3, then compare and evaluate the preset attitude threshold Z with the obtained machine attitude change coefficient Jq, and the attitude change of the underwater working robot model in the three-dimensional space; S4. When the posture is abnormal, the underwater environment is further analyzed, and the comprehensive motion coefficient Hl is obtained by performing correlation calculations based on the combined force received by the robot in the underwater environment; S5. Finally, a power threshold D is preset according to the obtained comprehensive motion coefficient H1, and a comparative evaluation is performed. The power of the underwater working robot is adjusted according to the evaluation result to stabilize the posture of the robot during underwater motion.

2. The method for establishing a dynamic model of an underwater working robot according to claim 1, characterized in that: By using SolidWorks 3D modeling, a robot model of the same scale is designed and established according to the selected robot type, and the appearance, joint structure and motion characteristics of the robot model are accurately modeled. At the same time, the geographic information system GIS is used to establish a terrain model of the underwater environment. The robot model and the underwater environment model are imported into the physical simulation engine Unity, and the physical engine is used to simulate the physical interactions in the underwater environment, including but not limited to water flow resistance, buoyancy and gravity.

3. The method for establishing a dynamic model of an underwater working robot according to claim 1, characterized in that: The earth coordinate system is set as the global fixed basic coordinate system and defined as the inertial coordinate system. The inertial coordinate system is defined as a right-handed coordinate system. The X1 axis is defined to point to the east, the Y1 axis to the north, and the Z1 axis to point upward. The absolute position and posture of the robot in space are analyzed. At the same time, the robot's own coordinate system is fixed to the robot's body. The position and posture of the robot relative to itself are analyzed and defined as the robot's own coordinate system. The robot's own coordinate system is defined as a right-handed coordinate system. The X2 axis is positioned to point in the robot's forward direction, the Y2 axis is defined to point to the robot's left side, and the Z2 axis is defined to point to the top of the robot.

4. The method for establishing a dynamic model of an underwater working robot according to claim 3, characterized in that: Through the defined inertial coordinate system and the robot's own coordinate system, the translation motion equation is used to analyze the position change of the robot in three-dimensional space, and the translation of the current underwater simulation robot is calculated using a three-dimensional vector It means that at this time, the machine translation motion coefficient Py is calculated through the translation motion equation; The translation motion coefficient Py is obtained by the following formula: ； Where v represents the velocity vector of the robot, v x1 、v y1 and v z1 They represent the velocity components of the robot on the x1-axis, y1-axis, and z1-axis in three-dimensional space respectively, and T represents the transpose operation of the vector.

5. The method for establishing a dynamic model of an underwater working robot according to claim 4, characterized in that: The rotational motion equation is used to analyze the robot's posture changes in three-dimensional space, and the quaternion is used to calculate the current underwater simulation robot's posture. Indicates that, by combining the robot's angular velocity , to obtain the robot's rotational motion coefficient Xz; The machine rotational motion coefficient Xz is obtained by the following formula: ； In the formula, represents the four-element selection matrix, q b represents the real part of the quaternion, q x2 ,q y2 and q z2 Represents the imaginary part of the quaternion, w x2 、w y2 and w z2 They represent the robot's rotation around the x2 axis, y2 axis, and z2 axis respectively.

6. The method for establishing a dynamic model of an underwater working robot according to claim 4, characterized in that: Then, the obtained translation motion coefficient Py and machine rotation motion coefficient Xz are dimensionlessly processed and correlated to calculate and output the machine posture change coefficient Jq; The machine posture change coefficient Jq is obtained by the following formula: ； Wherein, a1 and a2 represent the preset weight values ​​of the translation motion coefficient Py and the machine rotation motion coefficient Xz respectively, and their specific values ​​are adjusted and set by the user, and A is the correction constant.

7. The method for establishing a dynamic model of an underwater working robot according to claim 6, characterized in that: By presetting the attitude threshold Z of the underwater working robot according to the actual water environment and the power output of the machine, and then comparing and evaluating it with the obtained machine attitude change coefficient Jq, the current underwater working robot model in the three-dimensional space is analyzed. The specific evaluation method is as follows; When the machine attitude change coefficient Jq> attitude threshold Z, it means that the current robot's underwater power output causes the robot's attitude to deviate in the positive direction of motion. At this time, the underwater environment is further analyzed to adjust the power output of the robot's attitude. When the robot attitude change coefficient Jq = attitude threshold Z, it means that the current robot's power output underwater is normal and the robot's attitude is stable, and no further analysis is required at this time; When the machine posture change coefficient Jq is less than the posture threshold Z, it means that the current robot has abnormal hydrodynamic output, which causes the machine posture to deviate in the reverse motion direction. At this time, the underwater environment is further analyzed to adjust the power output of the robot posture.

8. The method for establishing a dynamic model of an underwater working robot according to claim 7, characterized in that: When the underwater robot model is in a simulated water environment and the power output causes an abnormal posture, the water force acting on the underwater working robot is comprehensively analyzed to perform a comprehensive analysis of the power output, where the water force includes the buoyancy Sfl, the robot's gravity in water Szl, and the water flow resistance Slz.

9. The method for establishing a dynamic model of an underwater working robot according to claim 8, characterized in that: By constructing a comprehensive formula to analyze the effect of the underwater environment on the robot's kinematics and dynamics, the water force is dimensionlessly processed and then correlated with the robot's translational motion coefficient Py and the robot's velocity vector v to obtain the comprehensive motion coefficient Hl. The comprehensive motion coefficient H1 is obtained by the following formula: 。 10. The method for establishing a dynamic model of an underwater working robot according to claim 9, characterized in that: It is used to compare and analyze the preset power threshold D with the obtained comprehensive motion coefficient Hl, analyze the power output of the current underwater robot, and adjust it. The specific evaluation plan is as follows; When the comprehensive motion coefficient Hl> the power threshold D, it means that the buoyancy of the current water environment is abnormal, which affects the posture and power of the robot. At this time, the propulsion force needs to be reduced step by step, and the propulsion force needs to be reduced by 5% each level to adjust the posture of the underwater robot; When the comprehensive motion coefficient Hl ≤ the power threshold D, it means that the water flow resistance of the current water environment is abnormal, which affects the posture and power of the robot. At this time, the propulsion force needs to be increased step by step, with each level increasing by 10%, to adjust the posture of the underwater robot.

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