Research On Mechanism Design And Gait Of Underwater Dredging Robot Based On Bionic Turtle

There is a large amount of silt at the bottom of artificially constructed rivers,lakes and fish ponds in cities,which seriously affects water quality.The existing dredging equipment cannot be effectively cleaned due to its poor adaptability to the environment.Therefore,how to clean up the silt in the complex underwater environment is a big problem.The underwater foot robot equipped with dredging equipment can walk on rugged and uneven underwater and complete dredging work through the coordination of its multiple legs.This subject imitates the structure and movement of the tortoise's legs,and designs an underwater four-legged dredging robot that can adapt to the complex underwater environment.And the movement process of the dredging robot is designed in detail.This article first describes the skeletal structure of the tortoise body and the crawling movements of the tortoise's limbs,as well as the position and posture relationship between one leg and the center of the tortoise.Using the tortoise body structure as a prototype,the structure of the body and legs of the four-foot dredging robot was determined.Calculate the degrees of freedom in the case of different numbers of supporting legs,and explain the jumping gait of the fuselage and supporting legs alternately.Based on this structural form,the driving mode,overall structure and control system scheme of the outriggers are determined in sequence.In this paper,the forward and inverse kinematics analysis of the center of the body and the end of the foot is carried out through the motion model and conversion matrix of the dredging robot.According to the relevant parameters of the front and rear legs,the actual pose of the body center is obtained.Then the Jacobian matrix is obtained to establish the basis for the subsequent dynamic analysis,and the turning principle of the dredging robot is explained.After introducing the movement of the quadruped,the movement sequence of the legs of the dredging robot is determined according to the principle of stability,and the movement characteristics of the three gait movements are analyzed and explained.Before carrying out the dynamic analysis of the dredging robot,this article first carries out foot-end trajectory planning and solves the control function of the body center trajectory and the outrigger driving mechanism.Then,the Lagrangian method is used to obtain the dynamic equations of single-leg swing and multi-leg support,and the relevant variables are substituted into the equations to obtain the driving torque and driving force of the legs in the two cases.The dynamic simulation verifies the feasibility of the dredging robot to move in a coordinated gait.The water impulse calculated by the software is added to the simulation model to obtain the influence of the water flow on the dredging robot under water.This article simplifies the control function curve of the drive mechanism,and reduces the performance requirements of the drive mechanism and controller.Then completed the design and selection of the hardware control system of the drive mechanism,the body and the legs in turn.Design the program framework of the gait controller responsible for coordinating and controlling the movement of each leg,and use Labview to write the upper computer control interface.In order to further analyze the movement of the dredging robot in the asynchronous state,a simplified experimental prototype is established at the end of this paper.Based on the control function of the driving mechanism of the dredging robot,the required extension length of the driving mechanism of the prototype in each sub-period is obtained.Then,the outrigger motion state and body deflection angle of the experimental prototype in the asynchronous state are used to analyze the stability of the dredging robot during the walking process and verify the correctness of the theoretical analysis.