Research On A Flexible Cylinder-driven Gripper

All kinds of grippers are commonly used in industrial automation production lines as grabbing and handling devices.These grippers are driven by high rigidity such as motor,hydraulic cylinder,air cylinder,and realize grasping action through different mechanical mechanisms.The grasping force is relatively large,but there is no flexibility,so it is not suitable for grabbing fragile articles.At present,the emerging soft grippers have good flexibility and safety and are suitable for grabbing fragile articles,but there are problems of small rigidity and small grasping force.The problem is that the quality of the object that can be grasped cannot be too large.Therefore,it is of practical significance and application prospect to study a new type of gripper with flexibility and large gripping force.To meet the actual demand,the following main research work has been carried out.According to the technical requirements of flexibility and large gripping force,a general structure of flexible cylinder-driven gripper is proposed.The gripper uses two pairs of flexible cylinders with driving flexibility as the driver.The lever mechanism and fingertip connecting rod mechanism are integrated to form a force transmission and grasping structure.The output force of the fingertip connecting rod flexible cylinder driver can be amplified by the force amplification of the lever mechanism,which greatly improves the grasping force of the gripper.On this basis,the theoretical modeling and simulation analysis of the characteristics of the gripper driven by the flexible cylinder is carried out,which provides the basis for the determination of the structural parameters of the whole gripper.A flexible cylinder is developed as a compliant actuator of the gripper.The flexible cylinder uses a corrugated pipe made of silicone rubber as the pneumatic driving inner pipe,and two rigid sliding pipes with clearance fit are used as the radial deformation limiting parts outside the corrugated pipe.The flexible cylinder can be extended and driven by the inflation and extension of bellows,and the return stroke of the flexible cylinder can be realized by vacuum-assisted rubber elastic potential energy.After the structure of the flexible cylinder is conceived,the basic characteristics of the flexible cylinder are simulated and analyzed,and the main structural parameters of the flexible actuator are determined;then the characteristics of the sample of the flexible actuator are tested.The test results show that: under the working pressure of 70 k Pa,the output force is about 50N;the fastest pressure response time of the flexible actuator is about 0.02s;it meets the technical requirements and lays the foundation for the realization of the flexible cylinder driven gripper.A test platform was established to test the overall grasping performance of the flexible driving gripper,and the adaptability of the gripper to different shapes of objects in different shapes was tested.Under the working pressure of 70 k Pa,the maximum weight of the object can be grasped by the gripper is 12.2kg,that is,the maximum gripping force is about 122 N,which is 2.4 times higher than the 3.5kg mass that the general flexible gripper can grasp,and the flexibility of gripping is also maintained.The whole research work has achieved the established goal and has a good research and application prospect.