Research On Flexible Pneumatic Manipulator With Rubber Bellows

In recent years,with the development of robot technology,various types of robots have continuously appeared.The application of flexible continuous robots with soft and flexible characteristics has attracted great attention.Flexible continuous robots can realize movements through continuous deformation of structures or changes the volume of actuators made of soft materials.In theory,it has unlimited degrees of freedom and can play a huge role in the fields of medical treatment,search and navigation.Therefore,it is significant to explore the structure and materials of flexible continuous robots and establish the kinematic model of flexible continuous robots.This article focuses on the kinematics of a flexible manipulator designed and manufactured with elastic rubber bellows driven by compressed gas.The main contents of the work are as follows:Due to the high safety requirements of the robot when man-machine cooperation,the driving scheme of the flexible manipulator is determined to be driven by compressed gas.The structure of the flexible manipulator is an actuator with an internal tension spring assembled in parallel as an actuator group,and the actuator group in series is assembled as a flexible manipulator.The principle of action is to change the volume of the actuator and realize the movement of the flexible manipulator by inflating compressed gas with different pressure into the actuator.The D-H method of the robot and geometric method are used to establish the kinematics model of the flexible manipulator to solve the problem of how to calculate the gas pressure of each actuator required by the flexible manipulator to reach the target position.A mathematical model between the coordinates(x,y,z)of the end center position,the attitude parameter(s,?,R)of center arc,the length(s1 s2,S3)of each actuator,and the air pressure(p1,p2,p3)of the actuator in the inverse motion analysis of the single-stage actuator group is established.The control and data acquisition system of the flexible manipulator is designed and built.The control program based on the inverse kinematics model of the actuator group is compiled by Lab VIEW.The deformation results of the actuator,the mathematical model between the length variation of the actuator and the internal air pressure when the single-stage actuator group is bent,and the inverse kinematics model of the single-stage actuator group were tested by the ventilation experiment.The results show that the actuator can withstand a maximum of 0.080MPa pressure gas and the longest can be extended to 486.0mm by the inflation test of the elastomer actuator.The maximum bending angle of the single-stage actuator group is 155°.The established mathematical model of actuator length variation and internal air pressure is verified to be accurate.The inverse kinematics model of the center position of the end of the actuator and the length of each actuator when the plane of the single-stage actuator group is bent is verified to be accurate.The pneumatic output control program of the flexible manipulator is compiled by Lab VIEW.Finally,the performance of the flexible manipulator was tested by the ventilation experiment.The flexible manipulator can grab and move 400g objects in the hollow hemisphere with a radius of 0.15m to 0.45m.The maximum extension of the flexible manipulator in the axial direction is 0.22m.The arm has a large working range and is suitable for human-machine cooperative work.