5-DOF Flexure Based Passive Gripper

Assembly is an essential process in industries in which one part has to be inserted into a hole. Owing to various tolerances, the part and the hole do not align which makes it difficult to assemble. Often to overcome this issue, power consuming active robotic gripper combined with expensive sensors ( force-torque, visual servoing, etc.) and complicated control loops are adapted.

In this project, I designed a 5-degrees of freedom (DOF) flexure based passive gripper for pick and insert tasks capable of handling limited misalignment. The complete operation is divided into three processes - picking, alignment during insertion and releasing. For each process, a mechanism based on flexures is designed. Owing to its passive design, the developed gripper does not require any additional power for its operation. Moreover, use of flexures eliminates joints and revolutes, making the gripper cost efficient and easy to manufacture as well as maintain.

(January 2016 - May 2016)

The optimized design of the gripper contains three major parts- mechanism for picking, releasing and an alignment mechanism. Numerical analysis was carried out in order to formulate capabilities and limitation of each mechanism. In order to validate the analytical calculation, Finite element method (FEM) based multibody dynamics software (SPACAR) was used. Further, a gripper was realised via SLS 3-D printing using PA (polyamide) material for picking an object, cuboid in shape, of dimension 20 mm × 20 mm × 40 mm and inserting into a hole of similar dimensions with wall thickness 2mm.

For detailed working of the gripper have a look at the poster that was presented at euspen’s 17th International Conference and Exhibition.