Research On Modeling And Control Of Flexible Manipulator Based On Pneumatic Muscle

The traditional rigid manipulator has the disadvantages of self-important mechanism and poor safety,and it is difficult to achieve light weight and flexibility.Researchers have proposed flexible manipulators with the advantages of light weight,good environmental adaptability,simple driving,small size,etc.,which has become a research focus of manipulator technology.However,the flexible manipulator has the disadvantages of low rigidity,low control accuracy and difficult control.Therefore,improving the rigidity and control accuracy of flexible manipulators,and researching the control methods of flexible manipulators have become the current research focus of flexible manipulator technology.In this paper,the flexible manipulator with adjustable stiffness is designed by combining the flexible drive and granular blocking mechanism;the stiffness adjustment characteristics of the flexible manipulator are studied through theoretical analysis and experimental research;the working principle of the flexible manipulator system is analyzed,and the mathematical model of the flexible manipulator pneumatic system is established;PID feedback control is used the control model of the flexible manipulator is established,and the numerical simulation analysis is carried out by using the Simulink tool,and the experimental platform is used for the experimental verification.The main contents and conclusions of this paper are as follows:1.The variable stiffness rod of the main component of the flexible manipulator is studied through the static theory analysis and experimental verification.A variable stiffness rod based on blocking mechanism is made by using POM particles as granular materials and silica gel materials as outer membrane.The blocking process of granular materials is analyzed.The static equation of the relationship between vacuum degree,type of outer membrane and stiffness of variable stiffness rod is obtained through static analysis.The accuracy of static equation of variable stiffness rod is verified by static experiment of variable stiffness rod.By changing the vacuum degree,the compression stiffness of the variable stiffness bar can be increased by 90.9%,the bending stiffness can be increased by 46.6%,and the shear stiffness can be increased by 61.1%;the compression stiffness of the variable stiffness rod is far greater than other stiffness,so the variable stiffness rod is suitable for supporting rod;2.Study the pneumatic system and control system of the flexible manipulator.Using the Festo pneumatic muscle as the outer membrane,combined with the blocking mechanism of the granular body,a new variable stiffness drive rod is designed,and the flexible robot arm is designed based on this;the pneumatic circuit system of the flexible robot arm is designed,the working principle of the pneumatic system is analyzed,and the components of the pneumatic system are selected;the control system of the flexible manipulator is designed,the working principle of the control system is analyzed,and the other elements are completed The flexible manipulator experiment platform was built;3.Analyze the mathematical model of the flexible manipulator system.The mathematical model of each part of the pneumatic system is analyzed,including the static model of pneumatic muscle,the dynamic model of pneumatic muscle and the model of solenoid valve.The kinematics model of flexible manipulator is constructed by geometric method,which lays the foundation for the control of flexible manipulator;4.Study the control strategy of the flexible manipulator through Simulink tool.Aiming at the problems of flexible control of flexible manipulators and low control accuracy,a closed-loop PID controller was designed;through Simulink numerical simulation analysis,the steady-state error of the length control accuracy of the flexible manipulator was ±5mm,and the convergence speed was 3.5s left and right;Finally,the effectiveness of the designed controller is verified through the experimental platform.