Design And Research On An Octopus-like Flexible Manipulator

Biomimetic flexible manipulator is a new type of manipulator which is inspired by the motor function of the mollusk.It has the advantages of high flexibility,wide range of motion and the capability of working in unstructured environment,which gives it a good application prospect in the field of aerospace and deep-sea exploration.To meet the requirement of large deformation of flexible manipulator in underwater unstructured environment,based on the analysis of octopus wrist muscle structure,a biomimetic flexible manipulator driven by SMA wires was developed with a control method proposed.A series of experiments about the biomimetic flexible manipulator were also conducted.Firstly,based on the research of biological characteristics,muscular tissue and movement mechanism of the octopus tentacle,this paper developed a flexible manipulator actuated by SMA wires.After structural design,the mechanical model on flexible deformation movement was built to obtain the relationship between the strain of SMA wires and bending angles of the flexible manipulator.Afterwards,a control method of the flexible manipulator was proposed.The theory of SMA wire was analyzed with the thermodynamic model and the constitutive model of SMA wire.The control model of flexible manipulator was established and simulated by Simulink.And the control system was designed based on application requirements,including hardware designing and software designing.Finally,the flexible manipulator prototype was developed and a test platform for experiments was set up.Some experiments were conducted to test motion performance and control performance.The motion experimental results showed that the flexible manipulator could achieve continuous flexible bending motion with a maximum bending angle of 60° and an optimal driving voltage of 13 V.The relationship between PWM duty cycle and the bending angle of flexible manipulator as well as the bending angle curve agreed well with the theoretical analysis.The control performance showed that the bending angle deviation was within 3 ? and the angle of deflection was within 12 ?,which verified the feasibility of both the flexible manipulator control method based on resistance feedback and the vector control method.