Research Of Parallel Cable-Driven Soft Modular Manipulator

Soft robotics has many advantages compared with traditional rigid robots in flexibility,adaptability and interaction.It is an important field in robot research around the world.The design inspiration of soft robotics mainly comes from animals in nature such as octopus and elephant drunk.These animals can freely twist,bend,do other forms of movement and manipulate objects flexibly.Soft manipulator which is made of flexible material can move flexibly and work safely.It has great aspects in the fields of elderly helping,medical rehabilitation,minimally invasive surgery,space operation and so on.It has become one of the important research directions in the field of soft robot.Based on the support rod structure of parallel robot,a new parallel cable-driven soft actuator is proposed in this paper.Modular soft manipulator is designed,which can realize both torsion and bending motion.The design,fabrication,kinematics modeling of the actuator and the assembly,kinematics modeling of the soft manipulator are studied.Firstly,most of the current soft manipulators can only realize the single motion.Inspired by the modularization of robots and arrangement of support rods of parallel robots,a cable-driven soft module which can achieve torsion and bending motion simultaneously.Through different combination of driven cables,bending and torsion motion can be realized.Based on the strain energy function,describe the stress-strain relationship of flexible material.The influence of three design parameters of the soft module to its motion performance is analyzed by using ABAQUS which is a finite element analysis software.On this basis,the module is prepared.Secondly,aiming at the problem that the non-linearity makes the kinematics modeling of soft module is difficult to establish.The kinematics model of bending motion and torsion motion are established based on the principle of energy conservation and piecewise constant curvature suppose.The model is validated by experiments.Using MATLAB to optimize the geometric parameters of the module to achieve a larger bending and torsion deformation angle when the same force is applied.Thirdly,a modular connection method is proposed.Based on this,multiple modules can be connected in series to form a soft manipulator.Aiming at the couple of multidriving force in the modeling of cable-driven soft manipulator,two kinematics model of parallel cable-driven modular soft manipulator are established by geometric analysis and equivalent substitution,respectively.An experiment platform is built to test bending and torsion motion of soft manipulator manufactured by two modules in series.The experimental results are compared with two model theories respectively.The feasibility of two modeling methods are verified and their advantages and disadvantages are compared.Finally,an experimental platform is built for testing the mechanical properties of the soft module and soft manipulator respectively.A bionic soft octopus manipulator is formed based on module combination.Some experiments are carried out to grasp the common items with different sizes,shapes,qualities and roughness.The diversified grasping function of the soft manipulator is verified.