Research On The Function And Kinematic Of The Pneumatic Arm With Flexible Structure

Traditional robotic arms have insufficient flexibility and low adaptability to unstructured environments,and cannot meet the development requirements of flexible and lightweight robotic arms.Therefore,it is urgent to develop a flexible manipulator with high flexibility and adaptability.According to the driving principle of the manipulator,the flexible manipulator can be divided into the following three categories: the manipulator based on the tendon drive,the integrated manipulator with the driver and the joint,and the variable stiffness manipulator.The rotational movement of the mechanical arm is usually driven by a motor,a rotary cylinder,and a hydraulic motor.Many robots have been developed based on gas-hydraulic power or electric motors at home and abroad,but both electric and hydraulic motors have the same problems,such as heavy mass,large inertia,and poor human-machine compatibility.The pneumatic forearm developed in this paper is the core component of the flexible manipulator,which is made up of self-developed antagonistic rotary joints and pneumatic flexible bending joints in series.Based on the principle of antagonistic drive,a joint antagonistic drive scheme was proposed to solve the problem of interference of the forward and reverse drive of the rotary joint.In addition,the antagonistic rotary joint was designed,the rotary joint driver was developed,the theoretical model of the rotary joint driver was established,and the statics experiment and movement of the rotary joint driver were completed.Finally learn the experiment to verify the theoretical model of the drive.The control system was built,the antagonistic rotary joint antagonism experiment was completed,the optimal installation preload of the joint was selected,and the rotary joint air pressure-torque experiment and air pressure-rotation angle experiment were carried out.The experiment showed that the joint can achieve any posture within the range of±68.5°controllable.The rotation speed response experiment of the rotary joint is completed.The time required for the joint to rotate to the maximum angle under0.3MPa is 0.85 s,and the maximum angular velocity of the joint is 100°/s.The method of maintaining the position and posture of the rotary joint was studied,the pneumatic brake was developed,the theoretical model of the pneumatic brake braking force was established,the wall thickness optimization design of the brake airbag was carried out,and the pneumatic brake braking force experiment was completed.When the pressure of the experiment surface is 0.3 MPa,the brake The braking torque is 4.21 N·m,which realizes the function of maintaining the joint position and provides an experimental basis for the later joint control.Pneumatic flexible bending joints are driven by pneumatic artificial muscles.The joint bending motion is similar to axis-free multi-hinge bending.The joint structure and movement flexibility are higher,and its motion is closer to natural biological joint motion.The statics model of the bending joint was established,the theoretical model was verified through experiments,and the statics and motion experiments of the bending joint were completed.The bending angle range of the joint was ±72.12°,and various performances of the bending joint were analyzed.Set up an experimental system and determine the experimental plan.According to the design requirements,the pneumatic forearm is installed horizontally and fixedly on the test bench,and the joint no-load and load experiment is completed in linkage with the wrist joint,the joint motion posture is analyzed,and the air pressure control strategy during the joint motion process is determined,which provides the theoretical and experimental basis for the later application of the pneumatic forearm.