Super-Friction Gecko Gripper Can Grasp Large Objects Without Squeezing
Most robotic grippers grasp objects with normal forces, either directly or indirectly, through friction. This method of grasping is effective for objects small enough for a given gripper to partially encompass. However, to grasp larger objects, significant grip forces and a high coefficient of friction are required. A team of Stanford University mechanical engineers have presented a new grasping method for convex objects, using almost exclusively shear forces, at ICRA 2015 in Seattle, WA. The engineers achieve shear grasping with a gripper that utilizes thin film gecko-inspired fibrillar adhesives that conform to the curvature of the object. This video shows the new conformal gecko adhesive film in action. It is very grippy yet not sticky at all. The video shows how the film can 'palm' a basketball, yet still grab and release a balloon under its own weigh.
Transcript
00:00:00 grasping without squeezing sheer adhesion gripper with fibr thin film in this work we present a gripper based on sheer adhesion provided by gecko inspired adhesives casts onto a thin flexible membrane a bable frame holds the film Tot but also allows the film to conform around curved objects when gently pressed onto the surface the gripper supports large loads
00:00:29 when pulled but releases easily when the frame is pulled straight here a robotic arm picks and places a variety of curved objects the PVC tube weighs over 2 kg the basketball has a diameter of 24 cm and a mass of 600 G the bottle has a diameter of 27 CM this version of the gripper is able to release objects by pressing them onto
00:01:19 the surface without requiring a release actuator this task is doable because the gripper does not squeeze when grasping the gripper is able to collapse and engage the adhesive fast enough to catch a ball here we grasp a large variety of curved objects with a handheld gripper this gripper is able to lift
00:02:11 over 1.5 kg it can grip textured surfaces as well as large objects is able to lift a leather wallet it can even lift soft objects like a foil wrapped burrito