CN-122021470-A - Flow field analysis method in underwater mechanical arm movement process

CN122021470ACN 122021470 ACN122021470 ACN 122021470ACN-122021470-A

Abstract

The application provides a flow field analysis method in a motion process of an underwater mechanical arm, which comprises the steps of determining a simulation motion parameter sequence of the mechanical arm in an underwater space, wherein the simulation motion parameter sequence comprises a plurality of simulation motion parameters which are arranged according to time sequence, determining a first coordinate parameter sequence of a target part of the mechanical arm and a second coordinate parameter sequence of a dynamic plane slice corresponding to the target part of the mechanical arm based on the simulation motion parameter sequence, wherein the dynamic plane slice is matched with a section where the target part is located, the first coordinate parameter sequence comprises a plurality of first coordinate parameters which are arranged according to time sequence, the first coordinate parameter comprises position point coordinates of a plurality of position points on the outer surface of the target part, the second coordinate parameter sequence comprises a plurality of second coordinate parameters which are arranged according to time sequence, and carrying out flow field analysis on the target part of the mechanical arm based on the first coordinate parameter sequence, the second coordinate parameter sequence and flow field data of the underwater space to obtain a flow field analysis result of the target part.

Inventors

ZHANG HAIYANG
XU MING
QIN FENGHUA
CHENG WAN

Assignees

中国科学技术大学

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. A method for analyzing a flow field in the movement process of an underwater mechanical arm, which is characterized by comprising the following steps: determining a simulation motion parameter sequence of the mechanical arm in an underwater space, wherein the simulation motion parameter sequence comprises a plurality of simulation motion parameters which are arranged according to time sequence; determining a first coordinate parameter sequence of a target part of the mechanical arm and a second coordinate parameter sequence of a dynamic plane slice corresponding to the target part of the mechanical arm based on the simulation motion parameter sequence, wherein the dynamic plane slice is matched with a section where the target part is located, the first coordinate parameter sequence comprises a plurality of first coordinate parameters which are arranged according to time sequence, the first coordinate parameters comprise position point coordinates of a plurality of position points on the outer surface of the target part, the second coordinate parameter sequence comprises a plurality of second coordinate parameters which are arranged according to time sequence, and the second coordinate parameters comprise position point coordinates of a plurality of position points on the dynamic plane slice; and carrying out flow field analysis on the target part of the mechanical arm based on the first coordinate parameter sequence, the second coordinate parameter sequence and flow field data of the underwater space to obtain a flow field analysis result of the target part.
2. The method of claim 1, wherein determining a second coordinate parameter sequence of a dynamic planar slice corresponding to the target portion of the robotic arm based on the simulated motion parameter sequence comprises: Determining a control function of a pose of the dynamic planar slice over time based on the simulated motion parameter sequence, the pose comprising at least one of a position and an angle of the dynamic planar slice; determining a second coordinate parameter of the dynamic plane slice at any time step pose based on the control function; And determining a second coordinate parameter sequence based on the second coordinate parameters of the pose of the dynamic plane slice at each of a plurality of time steps.
3. The method of claim 1, wherein determining a first coordinate parameter sequence of a target portion of the robotic arm and a second coordinate parameter sequence of a dynamic planar slice corresponding to the target portion of the robotic arm based on the simulated motion parameter sequence comprises: Determining a first coordinate parameter sequence of a target part of the mechanical arm based on the simulation motion parameter sequence; Determining an initial second coordinate parameter of the dynamic planar slice under the condition that the mechanical arm is at a starting movement position, and a relative position relation between the dynamic planar slice and the target part at the starting movement position; and based on the first coordinate parameter sequence and the relative position relation, carrying out coordinate updating on the initial second coordinate parameter in a plurality of time steps to obtain the second coordinate parameter sequence.
4. The method of claim 1, wherein performing a flow field analysis on a target portion of the robotic arm based on the first coordinate parameter sequence, the second coordinate parameter sequence, and flow field data of an underwater space to obtain a flow field analysis result of the target portion, comprises: Determining flow field data of a target space from the flow field data of the underwater space based on the first coordinate parameter sequence and the second coordinate parameter sequence, wherein the target space is a space between the outer surface of the target part of the dynamic plane slice and the edge of the dynamic plane slice; and carrying out flow field analysis on the target part of the mechanical arm based on the flow field data of the target space to obtain a flow field analysis result of the target part.
5. The method of claim 4, wherein the flow field data comprises pressure field data and velocity field data; Based on the flow field data of the target space, performing flow field analysis on a target part of the mechanical arm to obtain a flow field analysis result of the target part, wherein the flow field analysis result comprises: Integrating calculation is carried out on the resultant force of the pressure and the additional mass force applied to the target part based on the pressure field data and the speed field data of the target space, so that the total resultant force of the target part is obtained; and obtaining a flow field analysis result of the target part based on the resultant force.
6. The method of claim 5, wherein the flow field data further comprises vorticity field data; based on the total force, obtaining a flow field analysis result of the target part, wherein the flow field analysis result comprises the following steps: calculating the unsteady force of the target part caused by vortex shedding generated by the underwater simulation motion of the mechanical arm based on the vortex field data of the target space to obtain the unsteady force of the target part; and obtaining a flow field analysis result of the target part based on the total force and the abnormal force.
7. The method of any one of claims 1 to 6, wherein the target site comprises a plurality of the target sites in one-to-one correspondence with a plurality of the dynamic planar slices; the method further comprises the steps of: And respectively carrying out flow field analysis on the plurality of target parts of the mechanical arm based on the first coordinate parameter sequences of the plurality of target parts, the second coordinate parameter sequences of the plurality of dynamic plane slices and the flow field data of the underwater space, so as to obtain flow field analysis results of the plurality of target parts.
8. The method of claim 7, wherein one end of the robotic arm is secured to a base about which the robotic arm is movable, the plurality of dynamic planar slices dividing the robotic arm into a plurality of robotic arm segments; the method further comprises the steps of: Determining the total force of each of a plurality of mechanical arm segments based on flow field data of the space where each of the plurality of mechanical arm segments is located; And determining the moment of each of the plurality of mechanical arm segments relative to the base based on the total force of each of the plurality of mechanical arm segments and the distance between each of the plurality of mechanical arm segments and the base.
9. The method of claim 8, wherein the robotic arm comprises a first arm coupled to a base and a second arm coupled to the first arm by a joint; the method further comprises the steps of: Determining positional information of the joint relative to the base; Based on the moment of the plurality of mechanical arm sections of the second support arm relative to the base and the position information of the joint relative to the base, respectively, the moment of the plurality of mechanical arm sections of the second support arm relative to the base is converted into the moment of the plurality of mechanical arm sections of the second support arm relative to the joint.
10. The method according to any one of claims 1 to 6, further comprising: Determining a first space which is formed by the mechanical arm in the underwater simulation movement process and used for representing a wake flow area based on the movement range of the mechanical arm; Grid division is carried out on the first space by utilizing a first grid size, so that grids with the first size are obtained; and meshing a second space by using a second mesh size to obtain a second-size mesh, wherein the second space is a space of the underwater space except the first space, the first mesh size is smaller than the second mesh size, and the mesh is used for calculating flow field data of a corresponding position of the mechanical arm in the simulation motion process of the underwater space.

Description

Flow field analysis method in underwater mechanical arm movement process Technical Field The application relates to the technical field of hydrodynamic analysis and simulation post-treatment of underwater robots, in particular to a flow field analysis method in the motion process of an underwater mechanical arm. Background The underwater robot arm is subjected to complex hydrodynamic forces including drag, additional mass forces, and abnormal forces caused by vortex shedding when performing a job. The mechanical arm consists of a plurality of connecting rods and joints, and the movement of the mechanical arm is the combination of the relative rotation and translation of the adjacent connecting rods, so that the fluid bypass phenomenon of multiple movement modes is generated. The plurality of arm bars are mutually interfered under different postures, and the postures of the underwater mechanical arm are continuously changed in actual operation, so that the instantaneous hydrodynamic coefficient of the arm bars is obviously changed along with time. When the mechanical arm moves underwater and vortex street falls off, the wake flow area becomes unstable. These factors all increase the difficulty of force analysis and control during the movement of the underwater mechanical arm. In hydrodynamic analysis of underwater mechanical arms, at present, hydrodynamic parameters of the mechanical arms in all postures are generally obtained by computer simulation. However, there are still challenges to post-processing of simulation results. On the one hand, the simulation output data size is large, and the existing post-processing tool is difficult to directly extract certain key information, on the other hand, if the mechanical arm or the blunt body is in the motion process, the reference system is continuously changed relative to the flow field, and on the other hand, the traditional post-processing is difficult to conveniently obtain the flow field characteristics relative to the moving body. The prior art does not have a perfect scheme for carrying out high-efficiency post-treatment on the flow field of the underwater multi-motion-mode mechanical arm, and the requirement for rapid analysis on the characteristics of the flow field under complex working conditions is difficult to meet. Disclosure of Invention In view of the above, the application provides a flow field analysis method in the movement process of a mechanical arm. The flow field analysis method in the underwater mechanical arm moving process comprises the steps of determining a simulation motion parameter sequence of the mechanical arm in an underwater space, wherein the simulation motion parameter sequence comprises a plurality of simulation motion parameters which are arranged according to time sequence, determining a first coordinate parameter sequence of a target part of the mechanical arm and a second coordinate parameter sequence of a dynamic plane slice corresponding to the target part of the mechanical arm based on the simulation motion parameter sequence, wherein the dynamic plane slice is matched with a section where the target part is located, the first coordinate parameter sequence comprises a plurality of first coordinate parameters which are arranged according to time sequence, the first coordinate parameters comprise position point coordinates of a plurality of position points on the outer surface of the target part, the second coordinate parameter sequence comprises a plurality of second coordinate parameters which are arranged according to time sequence, the second coordinate parameter comprises position point coordinates of a plurality of position points on the dynamic plane slice, and carrying out flow field analysis on the target part of the mechanical arm based on the first coordinate parameter sequence, the second coordinate parameter sequence and flow field data of the underwater space to obtain flow field analysis results of the target part. According to the embodiment of the application, a second coordinate parameter sequence of a dynamic plane slice corresponding to a target part of the mechanical arm is determined based on a simulation motion parameter sequence, and the method comprises the steps of determining a control function of the pose of the dynamic plane slice along with time change based on the simulation motion parameter sequence, wherein the pose comprises at least one of the position and the angle of the dynamic plane slice, determining the second coordinate parameter of the pose of the dynamic plane slice at any time step based on the control function, and determining the second coordinate parameter sequence based on the second coordinate parameter of the pose of the dynamic plane slice at each of a plurality of time steps. According to the embodiment of the application, a first coordinate parameter sequence of a target part of the mechanical arm and a second coordinate parameter sequence of a dynamic plane slice cor