Mechanical Modeling And Experimental Verification Of Soft Biomimetic Manipulator

With the rapid development of robot technology,soft robots have gradually entered modern industrial production and human life because of their security and flexibility.As an important branch of robot research and supplement for traditional rigid robots,soft robots are mostly inspired by soft organisms derived from nature,such as starfish,jellyfish,octopus,elephant trunk,soft worms,tendrils of climbing plants,etc.whose main structure is composed of soft materials.Most of the current researches focus on material,actuator or structure design.The mechanical modeling of robots still need to draw lessons from traditional mechanical methods,and the complete modeling system for soft robots has not yet been formed.The material nonlinearity and structural nonlinearity of soft robots also increased the difficulty of modeling.The research on mechanical modeling of soft robots has great academic value and engineering guiding significance.In this dissertation,the mechanical analytical model and finite element numerical simulation analysis model of the soft bionic manipulator are established and verified by experiments.Based on the Cosserat geometric beam theory,the kinematics and static model of the soft bionic manipulator are established,and the closed-form analytical solution of the curvature,torsion and strain of the soft arm is derived.Considering the influencing factors,such as cable friction,elastic internal force and hydrodynamics,the segmented discrete dynamic model of the soft bionic robot arm is established based on the screw theory and the geometric Jacobian method.The Newton-Euler iterative algorithm is used to solve the dynamics equations in MATLAB.Based on the RecurDyn multi-body dynamics simulation software,this paper proposes a finite element modeling and simulation analysis process for the cable-driven soft bionic mechanical arm.The finite element physics simulation model of the cabledriven soft arm is constructed,and the equivalent simulation model of the flexible cable is realized.In order to confirm the properties of the simulation material,the tensile test of silicone material was carried out based on the Ogden constitutive model.The simulation of multi-modal motion of the soft bionic manipulator is realized by this finite element method,such as bending,axial shrinkage,elongation and the combined bending with torsion movement of octopus arm.Finally,two cable-driven soft bionic manipulator prototypes with different configurations and size are designed and fabricated based on the principle of octopus bionics.A characteristic test experimental platform for the cable-driven soft bionic manipulator is constructed.The motion control of the cable-driven soft arm is realized by C programming language and serial communication.The steady-state and dynamic bending experiments in different working conditions are completed.The curvature and strain model are corrected by experimental results.The mechanical analytical model and the finite element model are verified by experiment.