Design And Analysis Of Soft Pneumatic Gripper With Embedded Flexible Sensor

In recent years,with the development of computer science,material biomimetics,automation control and other scientific fields,soft robots and flexible actuators made of flexible materials have attracted more and more attention.As an end-actuating device,the soft manipulator has advantages over the traditional rigid claw due to its flexibility.However,there are also some problems such as complex preparation process,low output load and nonlinearity.In particular,the pneumatic soft actuator has poor air tightness,low integration and low versatility.In this paper,based on the movement principle of the three-jaw chuck,on the basis of the "fast pneumatic network" structure,a layered and step-by-step preparation method is adopted to propose a variable-pitch pneumatic gripper with embedded flexible sensors.The structure design,simulation analysis,parameter optimization,prototype preparation,control system construction and testing of the gripper were carried out.It not only improves the versatility of the gripper,but also completes the integrated preparation of the drive and sensor,and cooperates with the control system to complete the real-time monitoring and intelligent control of the gripper state.It is divided into the following parts:(1)Based on the aerodynamic "fast grid drive structure",the structure design scheme and fabrication process of a soft actuator are proposed.A flexible bending sensor based on carbon nanotubes was fabricated by using carbon nanotubes as conductive materials filled in PU sponges.The integrated fabrication of flexible bending sensor and soft driver and the design and verification of variable distance structure are completed.(2)In order to understand the bending characteristics of the soft actuator and the output force of the end,a cavity statics model of the soft actuator was established.Abaqus software was used to simulate the bending of the soft actuator,and the influence of hardness of silicone rubber material,cavity wall thickness and bottom sealing layer on the bending performance and the output force of the end were analyzed.The feasibility of bending action of soft drive is verified.(3)A real-time monitoring and multi-terminal input control system is developed based on the designed variable distance soft pneumatic gripper.The output of the brushless diaphragm pump is controlled by Bluetooth,infrared,PC software,key and other modes through the feedback of the sensor,so as to achieve the flexible grasp of the soft pneumatic claw.PID control algorithm is adopted to solve the problem of high error and low stability of sensor output.(4)Combined with the developed pneumatic control system,the bending Angle of the soft actuator and the relationship between the output force of the end and the input air pressure were tested.The performance test of flexible bending sensor is completed.The grasping diameter and grasping weight of the claw were tested.The maximum grasping diameter was 182 mm and the maximum grasping weight was about 900 g.The average measurement error of the bending sensor is 5.91%.The objects with different shapes and easily deformable and fragile objects are captured.The results show that the designed flexible pneumatic jaws with variable distance can grasp common objects.Through the structural design,simulation analysis,introduction of the preparation process,control system construction and grasping test of the variable-pitch soft pneumatic gripper,it can provide a theoretical and practical basis for the design of the soft pneumatic gripper.It provides a solution for the application of soft pneumatic grippers in industry.