Study On The Design And Motion Control Method Of Tactile Sensing Snake Robot

As one of the biomimetic robots,snake robots have attracted widespread attention due to their flexible body and abundant gaits,they utilize coordinated body movements to autonomously adapt to complex or unstructured environment.Currently,snake robots are mainly controlled by the speed or position of the joint angle,which enables them to move well according to the gait trajectory generated by the body shape of specified parameters or curve fitting.However,in complex environments such as rugged or multiple obstacles,snake robots cannot rely solely on their carried camera,which cannot perceive the status information of the whole body for planning the next movement.In such cases,movements may be ineffective,or even the actual movement direction is opposite to the targeted.Introducing tactile sensors is expected to enable the snake robot to perceive the interactive information between the body and the external environment,help the robot move more clearly and efficiently,mimicking natural snake movements.This thesis focuses on the problem that snake robots cannot achieve efficient autonomous motion only based on visual recognition or human observation in environments such as multiple obstacles.A flexible tactile sensor based on the principle of photoconductivity was designed to develop the snake robot with tactile sensing capability.An obstacle-aided locomotion control method of snake robots based on tactile environment sensing was proposed and experimentally validated.The specific research contents of the research are as follows:1)The overall scheme of snake robot with tactile sensing capability was designed.Firstly,based on the characteristics of obstacle environment,the design requirements for robot structure,tactile sensing and control method were analyzed.The adaptability and advantages of flexible optical waveguide tactile sensors were compared and analyzed.Secondly,based on the characteristics of optical fibers and the principle of light loss,the principle and process of implementing pressure detection response using flexible optical waveguide tactile sensors were analyzed.Then,joint structure,sensor circuit and module were designed,and the selection of components was completed.Finally,the limit angle and support structure strength of the robot joints were verified through geometric measurement calculations and finite element analysis,verifying the feasibility of the design.2)Flexible optical waveguide tactile sensors were designed and prepared,and their working performance were tested and analyzed.A prototype of a tactile sensing snake robot was built.Firstly,the preparation process of flexible optical fiber tactile sensors was designed,and preparation molds for flexible fibers was processed based on 3D printing technology.The preparation of flexible fibers based on mixed silica gel was completed.Secondly,the response performances of the prepared tactile sensors with different contact types of point,line,surface were tested.The pressure dynamic response function of the sensor based on power function is constructed,and the working error and performance of the sensor are analyzed.Finally,The prepared tactile sensors were installed on the joints of the snake robot,and a snake robot prototype with tactile sensing capability was built.3)The motion control method of tactile sensing snake robots in multi-obstacle environments was studied.Firstly,the kinematics model of the snake robots in plane motion was established,and the relationship between friction and the motion of the snake robots was analyzed.Secondly,the serpentine curve and its motion control function of the snake robots were studied,and the relationship between motion control parameters and the amplitude,frequency,and motion direction of the serpentine curve was analyzed.Then,the robot joint collision detection and joint status recognition signal features based on tactile sensing were studied,and a method for determining obstacle contact types during the movement of snake robots was analyzed.A motion control method for snake robots in obstacle environments was proposed.Finally,optimal motion control of the snake robot was achieved by combining the segment curve connecting method.4)The control performance of snake robots in obstacle environments was tested through simulation and experiments.Firstly,a simulation testing scenario for the snake robots was built using simulation software to test the effectiveness of control method for lateral undulation locomotion and segment curve connecting.The motion performance of snake robots under different conditions was analyzed.Finally,an experimental scene simulating obstacles environment was constructed and prototype motion experiments were conducted to verify the feasibility of the tactile sensing snake robot motion control method.The thesis includes 83 figures,18 tables,and 93 references.