Research On Dynamic Modeling And Control Method Of Pneumatic Soft Manipulator

Unlike traditional rigid robots,soft robots have strong environmental adaptability,flexibility and can absorb the energy by collision,interact with people or the environment safely,and simulate the continuous movement of biological systems.It has important application value in terms of military detection and medical operations.The current study is mostly focused on improving the compliance performance,but less consideration is given to its rigid-flexible controllability in tasks and trajectory control of soft robots.Although soft robots exhibit various advantages that other types of robots cannot match,it still has some technical problems,which severely restrict its practical application in important scenarios.And the most prominent of these problems are,to establish accurate kinematic and dynamic models and control.Combining the advantages of actively driven pneumatic network structure and variable stiffness structure,this paper designs a soft manipulator with stiffness structure.Through theoretical and finite element analysis,to verify the rationality of the mechanism and further establish kinematics and dynamic models of the soft robot.Further,establish a sliding mode controller to control the trajectory of the manipulator.The specific content is:Firstly,analyze the driving mode and materials of actuator,we choose the silica gel and pneumatic actuator to make the manipulator.And analyze the principle of the variable stiffness to design the structure and finite element analysis,then this paper design a soft manipulator with variable stiffness structure,which is composed of multiple unit modules,each unit module includes three parts: pneumatic drive structure,a blockage variable stiffness structure,and silicone fiber composite layer.Secondly,this paper used the piecewise constant curvature method to model the soft manipulator.On this basis,the relationship between the end-center pose and joint variables are analyzed.Further,the dynamic model of the soft manipulator is obtained by Lagrange Equtions.On the basis of understanding of the principle of sliding mode control and the dynamic model established,this paper proposed a sliding mode control and stability analysis and simulation are carried out to verify.Thirdly,the selection of materials and equipment for making pneumatic soft manipulator is addressed.By using 3D printing technology and silica gel irrigation technology,we make the pneumatic structure,variable stiffness structure and silicone fiber composite layer.And integrate the three modules to produce a soft manipulator.Finally,the pneumatic control system is designed and the test platform is built to test the bending,tensile and speed performance of the soft robot and verify the relationship between bending angle,stretch length and air pressure,and verify the stability and structure of the soft manipulator designed.At the same time,the blocking structure is coupled to adjust the stiffness.Then we apply the force-displacement test while the soft robot under different stiffness conditions to verify the bending and moving performance of the soft manipulator with variable stiffness.