One-finger gripper based on the variable van der Waals force used for a single nano/micro-sized object

Abstract

This article presents the development of a one-finger gripper that uses a variable van der Waals force to grip, transport and actively release a single SiO2 spherical-like nano/micro-sized object. The diameters of the objects used (spheres) were between 800 nm to 50 μm. The van der Waals force becomes the dominant force for such objects (from 60 nN to 8 μN) if the materials are not electrically charged or have magnetic characteristics, and if the medium between the object and the one-finger gripper is a vacuum. Furthermore, the van der Waals force is several times greater than the gravitational force for such objects, so a two-finger gripper becomes unreliable when actively releasing a nano/micro object. Usually, the nano/micro object remains attached to one of the fingers at an unknown position and orientation. Our newly developed one-finger gripper does not have such problems. The van der Waals force between the gripper and the nano/micro object is increased by the deposition of H2O crystals on the gripper’s tip (gripping procedure), and decreased by sublimation of H2O crystals on the gripper’s tip (releasing procedure). This article presents both the theoretical conditions for the gripping/releasing of rigid spherical-like objects and experimental proof of these conditions. The results of our practical experimentation show that the gripping/releasing method can be applied to any shape of object and also to different materials.

Reliable and Accurate Release of Micro-Sized Objects with a Gripper that Uses the Capillary-Force Method

“…A nano-precision robotic system [ 13 , 20 ] was used to move the gripper ( Figure 1 ). The robotic workspace has a volume of approximately 1.5 cm 3 .…”

“…A more precise description of the nano-precision robotic system can be found in [ 13 , 20 ]. These include the position control system, the mechanical design, man-machine communications, and other technical details.…”

“…The reason why the proposed method is crucial is that it is useful for building 3D constructions, due to its reliable releasing and reliable “disassembling gripping”. Not all of the reviewed techniques presented in this section can be used for 3D assembling, with the exception of techniques [ 13 , 14 , 15 ] and possibly [ 11 , 12 ]. However, without exception, none of the reviewed techniques in this section can be used for 3D disassembling.…”

DenseTact: Optical Tactile Sensor for Dense Shape Reconstruction

“…Soft-robotic hand-like grippers have been proposed to pick up objects of various sizes, largely depending on the size and dimension of the gripper design [1], [2]. Some gripper designs lean on van der Waals forces for specifically picking up micro-scale objects [3], or maximizing them in a gecko-inspired fashion [4]. Such grippers are capable of gripping either tennis ballsized or micro-sized objects, but fail to grasp smaller and Manipulation of smaller objects has been extensively explored from multiple perspectives.…”

Design of a New Modular Reconfigurable Gripper

“…There are many types of grippers based on the number of fingers. For instance, in reference [2], one finger gripper is presented and developed. The gripper uses variable van der Waals force to perform the grip, move and release spherical nano/micro-sized objects.…”